web-archive-uk.com


Web directory, archive
Search web-archive-uk.com:


Find domain in archive system:
web-archive-uk.com » UK » C » CHAM.CO.UK

Total: 682

Choose link from "Titles, links and description words view":

Or switch to "Titles and links view".
  • ROSA
    comprises the following modules linked by a menu system The river current sub models The oil spill sub models The data entry module The visualisation module Oil pollutants within the river are considered as consisting of A surface slick floating on the water surface A mixed layer containing suspended oil fragments There is continuous exchange between the two layers and mass losses to the atmosphere The surface layer thickness is much less than that of the suspended layer which is equal to the flow depth ROSA Validation ROSA has been validated against a number of reliable laboratory and field measurements of velocity field and free surface elevations in two and three dimensions for open channels and river courses Free surface flows in open channels A number of free surface flows have been simulated and validated against experimental data including flow in open turnaround channel abrupt open channel expansion flow impingement on bluff body merging of streams flows in channels with complex bed shapes and meandering open channel flows Good agreement has been achieved both for free surface elevation and velocity distributions Other capabilities ROSA is a modelling tool capable of simulating movement of oil and other pollutants on the surface

    Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_phoen/rosa.htm (2016-02-15)
    Open archived version from archive


  • Finding out more about ...
    getting operated VR Environment VR Editor VR Editor hand set VR Editor object dialogs copying and deleting objects or groups treatment of solid fluid boundaries PARSOL default geometries VR Editor

    Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_docs/help/topics.htm (2016-02-15)
    Open archived version from archive

  • TR314: CVD User Guide Appendix 1
    Binary diffusion coefficients for the gas pairs are also obtained from kinetic theory although a correction factor suggested by Wilke and Lee is also included the result is 14 where is the average collision diameter for the pair and Dij T is a tabulated function of the Lennard Jones parameters and temperature 2 1 8 Thermal diffusion coefficients Thermal diffusion modelling requires the use of multicomponent diffusion coefficients that are dependent on mixture composition Derivation from kinetic theory is computationally expensive and increases as the cube of the number of gas species present the problem lies in the evaluation of large determinants having elements which are themselves complicated functions of gas composition and temperature As an alternative to this a simpler model proposed by Clark Jones has also been inc luded in PHOENICS CVD use of this method results in 15 where the thermal diffusion factors a ij are functions of molecular masses and Lennard Jones parameters The user can select either the exact or the Clark Jones approach as a further computational economy each formulation can be simplified by the use of the rigid elastic spheres approximation instead of the Lennard Jones potential 2 1 8 Data input PHOENICS CVD is equipped with two data files for transport and thermodynamic parameters The user is able to add new species with complete freedom following a standard format 2 2 Chemistry Modelling The fundamental process in Chemical Vapour Deposition is the chemistry that brings about the creation of the required film on the solid surface inevitably this involves surface chemistry but generally there are also gas phase reactions Many simulation studies have relied on very simple models for the chemistry with rate constants estimated from experimental data while this approach might yield accurate predictions for the process conditions under which th e data were collected it is of limited value in the main field of predictive modelling A deeper understanding of chemistry is also essential for studying conformality dopant incorporation and the important effects that intermediates can have on process characteristics such as selectivity and deposit morphology More detailed chemistry models have appeared recently but they have typically only been applied in conjunction with idealised reactor configurations PHOENICS CVD has been designed to facilitate the handling and solution of more sophisticated chemistry formulations in addition to the simpler models for both gas phase and surface reactions Numerical modelling can then be used to gain fundamental insight into the underlying phenomena 2 2 1 Gas phase chemistry Although not contributing directly to the deposition process itself gas phase chemistry plays an important role particularly in atmospheric pressure reactors the consumption of reactants and the formation of intermediaries may easily influence film quality The k th reversible gas phase reaction is written as 16 where n ik 0 5 n ik n ik In modelling terms the gas phase chemistry contributes the final terms to the species and energy equations 2 and 3 The net reaction rate is obtained from 17 where k k and k k are the forward and reverse reaction rate constants respectively These constants are strongly dependent on temperature and independent of pressure at sufficiently high pressures At lower pressures though there is pressure dependence A number of alternative formulations for the forward reaction rate constant have been included in PHOENICS CVD The simplest is the extended Arrhenius expression k k A Tb exp E A RT p c 18 More complicated alternatives are the Lindemann form which blends two Arrhenius expressions one for low and one for high pressure Further complexity is also available in the Troe form based on nine or ten parameters For reversible reactions the reverse reaction rate constant is calculated from equilibrium thermochemistry utilising the equilibrium constant for the reaction this is derived from polynomial fits for standard heat of formation standard entropy and specific heat 2 2 2 Surface chemistry Surface chemistry can be written in the same way as the gas phase reactions described above 19 where the A i i 1 N are the gaseous reactants and products and the B j j 1 M are the bulk or adsorbed reactants and products s il and c jl are the stoichiometric coefficients for the l th surface reaction The growth rate is simply calculated from the reactions that deposit the bulk species 20 where m s is the molar mass of the bulk species and r s is its density Surface reactions did not appear explicitly in the species and energy equations 2 and 3 earlier This is because they are included as boundary conditions rather than source terms 2 2 2 1 Semi empirical surface chemistry models In many chemistry models the surface chemistry is simplified into one or more irreversible reactions with only gaseous reactants and apart from the deposited species only gaseous products Equation 19 then simplifies to 21 Semi empirical methods have been developed for the definition of the surface reaction rates and two of these have been included as built in options The first involves the reactive sticking coefficient defined as the fraction of gas molecules colliding with the surface that contribute to the deposited film The reaction rate then becomes 22 where p A is the partial pressure of the reactant and T s the temperature at the surface the sticking coefficient is g A 1 and the remainder of the expression comes from kinetic theory Arrhenius expressions can be used for the sticking coefficient specified via the chemistry data file A second built in formulation is that by Langmuir Hinshelwood here the reaction rate is in the general form 23 Again the coefficients are specified in the data file 2 2 2 2 Detailed surface chemistry models The simplified surface chemistry models described above take no account of the adsorption of reactants and intermediaries at the surface their decomposition and the desorption of reaction products Although several more sophisticated models have been suggested in recent years there is still no standard form for them In general therefore the inclusion of new models requires user coding to be added to PHOENICS CVD this facility is provided and a number of specific models have been incl uded in the code to help users The solution strategy for detailed surface chemistry models is rather different from that usually employed At the surface the fractional coverages of the adsorbed species are calculated using a separate solver for the simultaneous calculation of stiff surface chemistry the resultant fluxes of reactants intermediaries and products are then imposed in the normal way as boundary conditions to the transport equations for the gas species 2 2 3 Numerical complications The solution of the transport equations for CVD processes is often hampered by numerical difficulties These result from the chemistry source terms which lead to strong coupling between the mass fractions of different species at a single location transport equations are usually solved on the basis that the strongest links are given by the convection and diffusion terms which link concentrations throughout the solution domain Additionally a single chemistry model is likely to contai n reactions with vastly differing time scales this stiffness can impose unacceptable limitations on the convergence that can be achieved Various techniques have been suggested to alleviate these problems but they cannot usually be applied to two and three dimensional elliptic problems In PHOENICS CVD convergence is improved by the linearisation of the chemistry source terms which increases the stability of the solution method The stiffness is addressed by the provision of an automatic under relaxation based on local creation and destruction rates In extreme cases this may still not be sufficient and an alternative solver has been provided this solves the species equations on a point by point basis using a Newton Raphson solver for the simultaneous solution of all the species in a single computational cell Such a technique is well suited for handling large sets of chemical reactions with widely varying time scales however because it is a local method convergence may still be slow because the convective and diffusive contributions are less well dealt with In some cases the use of both solvers in turn may be beneficial 2 2 4 Data input Specification of the chemistry to be adopted is made easy by the use of a data file For each of the numbered reactions the user is able to specify the chemical reaction in terms of species and stoichiometric coefficients the nature of the model to be adopted e g kinetic limited diffusion limited Langmuir Hinshelwood and the appropriate values of the parameters in the model 2 3 Radiation Modelling Radiation is a major element in heat transfer within CVD reactors in addition to convection conduction and diffusion The nature of radiation is such that it does not fit easily into the framework of computational fluid dynamics because of the links it introduces between remote parts of the solution domain Radiation terms therefore appear as source terms calculated in a totally different manner from the other mechanisms of heat transfer CVD gases are typ ically transparent to radiation and a surface to surface model is therefore sufficient There are two basic formulations viewfactor based or Monte Carlo Both approaches were successfully adopted within the ACCESS CVD Project although the Monte Carlo coding was restricted to axisymmetric geometries Time constraints made it impossible for the Monte Carlo coding to be included in the first commercial release of PHOENICS CVD it is intended to add it to a later code update In each approach the surfaces in the reactor are divided into zones within which the temperature and surface optical properties are assumed to be constant The radiative heat source to the i th zone is given by 24 where T j is the surface temperature of the j th zone s is the Stefan Boltzmann constant and R is the radiative exchange matrix This heat source is used together with the other fluxes to calculate the zone surface temperature iteratively as the general solution proceeds It is the radiative exchange matrix that is calculated by the viewfactor or Monte Carlo approach 2 3 1 Viewfactor model The viewfactor from the j th to the i th thermal zone is given by 25 where r is the distance between the points in each zone n i and n j are the two surface normals and A j is the surface area of the j th zone is the transmittance from j to i in the l th spectral band If all surfaces are opaque the viewfactors are purely geometrical properties of the reactor the introduction of semitransparent solids means that the viewfa ctors must be recalculated if the degree of transparency changes e g as a result of a changing surface temperature Calculation of the energy flux from j to i in the l th spectral band is calculated using the Gebhard factors 26 which take account of direct and multiply reflected radiation r l m and a l m are the reflectivity and absorptivity of the m th zone in the l th band The net flux in the l th band is then given by 27 where is the fraction of black body radiation in the l th band The total radiative heat source as given above includes the full radiation exchange matrix which is the sum of the matrices for each spectral band The surface temperature of each zone is calculated iteratively as the solution proceeds and the surface temperature used for the viewfactors should take account of this For simplicity a user specified value for each zone is used to avoid frequent recalculation of the radiation exchange matrix Greater accuracy can be achieved if the specified surface temperatures are modified manually and the solution restarted typically a single iteration of this type is sufficient The calculation of the viewfactors between zones is carried out by means of a ray tracing algorithm which detects obstructions opaque or semitransparent The geometrical viewfactors are then derived using a modified double integral method which takes account of singular integrals when zones are in contact For computational efficiency the spectral variation of surface properties is implemented in a banded manner this is sufficient for most purposes 2 3 2 Monte Carlo model The Monte Carlo method is the same in principle as before a radiative exchange matrix is generated from which heat sources can be determined However in this case the calculation is based directly on rays traced from each zone in turn until after reacting with other surfaces they reach their final destinations A large number of rays are used sampled from the appropriate angular and spectral distributions for the emitting and any intermediate reflecting and transmitting surface s so that a statistically significant picture can be built up showing how much energy from a surface will be received at each other zone An advantage of the Monte Carlo approach is that it permits specular reflection to be simulated this can be particularly useful for the highly reflective surfaces in reactor lamphouses Furthermore the spectral variation of properties can be exact rather than in discrete bands 2 3 3 Data input A data file is used to specify the optical properties of any materials that are used in the simulation The file contains for each numbered material a set of coefficients used in the calculation of the real and imaginary parts of the refractive index for each of sixty spectral bands these cover the wavelength range from 10 7 m to 10 4 m representing temperatures from 250K to 6000K Simplified non spectral modelling is also permitted and for this the data file c ontains constant values of emissivity and reflectivity Additional materials can easily be added by users 2 4 Plasma Modelling In recent years the use of plasma enhanced chemical vapour deposition PECVD has become more common the ability to provide the energy required for CVD chemistry without the undesirable side effects of high thermal stress and poor controllability that are often a problem in conventional thermally energised systems makes it an attractive option for a range of processes The modelling of plasma based chemistry is inherently more complex than the modelling of comparable neutral gas processes Apart from the need to model additional variables associated with the electrons ions and electric field there is the notably non equilibrium state of the plasma the energy is taken up much more readily by the light electrons than the heavier ions and neutrals which typically remain close to the ambient temperature Various methods for plasma modelling exist usually based either on fundamental laws of physics or engineering approaches containing mainly empirical information The first category are typically very computer intensive while the second yield only qualitative results The perceived need within the ACCESS CVD Project was for a model that was simple enough to be compatible with the computational times for the rest of the simulation but still able to produce valuable quantitative results Th e outcome was the Eddy Drift Diffusion Model EDDM which has been implemented in PHOENICS CVD This model is explicitly geared towards capacitively coupled discharges in the PECVD regime within those limits it is equivalent to the more fundamental fluid dynamical approach from which it is derived but without such demanding computational requirements 2 4 1 Fluid dynamical plasma modelling Unlike general kinetic models which describe a plasma in terms of distribution functions fluid dynamical plasma models use macroscopic variables such as densities bulk velocities and pressures Such a model for an RF discharge would require equations for electron density and energy or temperature density and velocity for each type of ion and also electrical potential With appropriate boundary conditions these partial differential equations would describe the evolution of a low p ressure discharge under an applied electric field For periodic RF excitation it would be necessary to solve the transient equations until the asymptotic limit cycle was reached the transient effects typically lasting only a few milliseconds are of little interest for CVD plasma processes This approach has been shown to be very reasonable but extremely slow One reason for this is that stability and accuracy require time steps in the transient calculation which are small compared with the driving RF frequency as a large number of cycles are required before the limit cycle is reached this leads to unreasonable run times This is another example of numerical stiffness see chemistry section above the electrons and the ions are described within the same framework yet the dynamical phenomena act on vastly different time scales 2 4 2 The Effective Drift Diffusion Model The Effective Drift Diffusion Model overcomes the stiffness problem by making use of additional simplifications to the fluid dynamical equations further the limit cycle is calculated directly with no attempt to model the transient evolution The simplifications are based on the very circumstances which have caused the numerical stiffness in the first place the pronounced scale separation of the dynamics Specifically the following assumptions are introduced the characteristic length scales of the plasma Debye length mean free path are small compared with the scale of the reactor the discharge can then be separated into the bulk which is numerically resolved and the thin boundary sheaths at electrodes and walls which are represented by boundary conditions the characteristic frequencies of the electrons particularly the dielectric relaxation frequency are high compared with the applied frequency the electrons are then quasi static or in Boltzmann equilibrium the dynamic frequencies of the ions ion plasma frequency ionization rate are small compared with the RF frequency the ions can then be regarded as stationary reacting only to average field values With these assumptions the plasma can be modelled in three parts plasma transport RF modulation and energy balance Plasma transport The quasi neutrality of the plasma resulting from the speed of the dielectric relaxation means that the electron charge density equals the net ion charge density 28 where e and n are

    Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_docs/tr314/tr314-a1.htm (2016-02-15)
    Open archived version from archive


  • TR314: CVD User Guide Appendix 2
    2 900000E 02 OBJ NAME RI003 OBJ POSITION 0 000000E 00 1 000000E 01 9 999999E 02 OBJ SIZE 1 000000E 02 0 000000E 00 4 000001E 02 OBJ GEOMETRY polcusrf OBJ ROTATION24 1 OBJ TYPE RAD SURF OBJ OBJECT SIDE HIGH OBJ SETTING AUTO OBJ TEMP COEF GRND1 OBJ OPTIC INDX 1 110000E 02 OBJ OPTIC TEMP 3 000000E 02 OBJ NAME RI004 OBJ POSITION 0 000000E 00 1 000000E 01 1 400000E 01 OBJ SIZE 1 000000E 02 5 000003E 03 0 000000E 00 OBJ GEOMETRY polcusrf OBJ ROTATION24 1 OBJ TYPE RAD SURF OBJ SETTING AUTO OBJ TEMP COEF GRND1 OBJ OPTIC INDX 1 110000E 02 OBJ OPTIC TEMP 3 000000E 02 OBJ NAME RI005 OBJ POSITION 0 000000E 00 1 050000E 01 9 999999E 02 OBJ SIZE 1 000000E 02 0 000000E 00 4 000001E 02 OBJ GEOMETRY polcusrf OBJ ROTATION24 1 OBJ TYPE RAD SURF OBJ SETTING AUTO OBJ TEMP COEF GRND1 OBJ OPTIC INDX 1 110000E 02 OBJ OPTIC TEMP 3 000000E 02 OBJ NAME RI006 OBJ POSITION 0 000000E 00 1 050000E 01 9 999999E 02 OBJ SIZE 1 000000E 02 1 050000E 01 0 000000E 00 OBJ GEOMETRY polcusrf OBJ ROTATION24 1 OBJ TYPE RAD SURF OBJ OBJECT SIDE HIGH OBJ SETTING AUTO OBJ SURF TEMP 2 900000E 02 OBJ OPTIC INDX 1 110000E 02 OBJ OPTIC TEMP 2 900000E 02 OBJ NAME RI007 OBJ POSITION 0 000000E 00 2 100000E 01 9 999999E 02 OBJ SIZE 1 000000E 02 0 000000E 00 2 400000E 01 OBJ GEOMETRY polcusrf OBJ ROTATION24 1 OBJ TYPE RAD SURF OBJ SETTING AUTO OBJ SURF TEMP 2 900000E 02 OBJ OPTIC INDX 1 110000E 02 OBJ OPTIC TEMP 2 900000E 02 OBJ NAME RI008 OBJ POSITION 0 000000E 00 1 550000E 01 3 400000E 01 OBJ SIZE 1 000000E 02 5 500001E 02 0 000000E 00 OBJ GEOMETRY polcusrf OBJ ROTATION24 1 OBJ TYPE RAD SURF OBJ SETTING AUTO OBJ SURF TEMP 2 900000E 02 OBJ OPTIC INDX 1 110000E 02 OBJ OPTIC TEMP 2 900000E 02 OBJ NAME RI009 OBJ POSITION 0 000000E 00 1 550000E 01 2 400000E 01 OBJ SIZE 1 000000E 02 0 000000E 00 9 999996E 02 OBJ GEOMETRY polcusrf OBJ ROTATION24 1 OBJ TYPE RAD SURF OBJ OBJECT SIDE HIGH OBJ SETTING AUTO OBJ SURF TEMP 2 900000E 02 OBJ OPTIC INDX 1 110000E 02 OBJ OPTIC TEMP 2 900000E 02 OBJ NAME RI010 OBJ POSITION 0 000000E 00 1 200000E 01 2 400000E 01 OBJ SIZE 1 000000E 02 3 499999E 02 0 000000E 00 OBJ GEOMETRY polcusrf OBJ ROTATION24 1 OBJ TYPE RAD SURF OBJ SETTING AUTO OBJ SURF TEMP 2 900000E 02 OBJ OPTIC INDX 1 110000E 02 OBJ OPTIC TEMP 2 900000E 02 OBJ NAME RI011 OBJ POSITION 0 000000E 00 1 200000E 01 2 350000E 01 OBJ SIZE 1 000000E 02 0 000000E 00 5 000010E 03 OBJ GEOMETRY polcusrf OBJ ROTATION24 1 OBJ TYPE RAD SURF OBJ SETTING AUTO OBJ TEMP COEF GRND1 OBJ OPTIC INDX 1 110000E 02 OBJ OPTIC TEMP 9 000000E 02 OBJ NAME RI012 OBJ POSITION 0 000000E 00 0 000000E 00 2 350000E 01 OBJ SIZE 1 000000E 02 1 200000E 01 0 000000E 00 OBJ GEOMETRY polcusrf OBJ ROTATION24 1 OBJ TYPE RAD SURF OBJ OBJECT SIDE HIGH OBJ SETTING AUTO OBJ TEMP COEF GRND1 OBJ OPTIC INDX 1 110000E 02 OBJ OPTIC TEMP 9 000000E 02 STOP strong pre body html Tungsten Reactor The tungsten reactor has a showerhead inlet the details of which are not modelled instead a uniform inlet is specified The inlet flow is 6 hydrogen and 94 tungsten hexafluoride by mass corresponding to approximately 90 hydrogen by volume Gas phase chemistry is less important in this case and only a single surface reaction is used in the simulation The showerhead structure is a very significant part of the problem because of its thermal effect it is heated radiatively by the hot tungsten susceptor 733K and in turn passes heat to the gas by convection and to the outer wall by radiation html head title Q1 title link rel stylesheet type text css href phoenics d polis polstyle css head body pre strong TALK T RUN 1 1 Q1 created by VDI menu Version 2006 Date 21 09 06 CPVNAM VDI SPPNAM CVD Echo DISPLAY USE settings DISPLAY This file simulates a simple chemical vapour deposition reactor for depositing tungsten the reactor is axisymmetric and the geometry was provided by Siemens Laminar steady state flow is assumed The susceptor temperature is 733K ENDDIS IRUNN 1 LIBREF 304 Group 1 Run Title TEXT Tungsten Reactor normal inlet D304 Group 2 Transience STEADY T Groups 3 4 5 Grid Information Overall number of cells RSET M NX NY NZ tolerance RSET M 1 37 35 7 347740E 05 Cylindrical polar grid CARTES F Group 6 Body Fitted coordinates Group 7 Variables STOREd SOLVEd NAMEd ONEPHS T Non default variable names NAME 16 S177 NAME 17 S80 NAME 18 S97 NAME 139 SPH1 NAME 140 KOND NAME 141 ENUL NAME 142 BLOK NAME 143 PRPS NAME 144 DEPO NAME 147 EMIS NAME 148 VPOR NAME 149 RHO1 NAME 150 TEM1 Solved variables list SOLVE P1 V1 W1 S80 S97 TEM1 Stored variables list STORE RHO1 VPOR EMIS DEPO PRPS BLOK ENUL KOND STORE SPH1 S177 Additional solver options SOLUTN P1 Y Y Y N N N SOLUTN S80 Y Y Y N N Y SOLUTN S97 Y Y Y N N Y SOLUTN TEM1 Y Y Y N N Y IVARBK 1 ISOLBK 1 Group 8 Terms Devices DIFCUT 0 000000E 00 NEWRH1 T NEWENL T UDIFF T UDIFNE T USOURC T ISOLX 0 ISOLY 0 ISOLZ 0 Group 9 Properties PRESS0 1 330000E 02 Domain material index is 70 signifying CVD GAS SETPRPS 1 70 Q1 ENUT 0 000000E 00 DVO1DT 1 000000E 00 PRNDTL S80 GRND8 PRNDTL S97 GRND8 PRNDTL TEM1 GRND8 PRLH1A 0 000000E 00 PRLH1B 0 000000E 00 PRLH1C 0 000000E 00 List of user defined materials to be read by EARTH MATFLG T IMAT 2 Name Ind Dens Viscos Spec heat Conduct Expans Compr CVD GAS 70 GRND8 GRND8 GRND8 GRND8 1 000 0 000 constants for GRND option no 1 0 0 constants for GRND option no 2 0 0 constants for GRND option no 3 0 0 constants for GRND option no 4 0 0 USRM2 154 1 926E4 1 0 134 0 178 0 0 0 0 0 Group 10 Inter Phase Transfer Processes Group 11 Initialise Var Porosity Fields FIINIT P1 0 000000E 00 FIINIT V1 0 000000E 00 FIINIT W1 0 000000E 00 FIINIT S177 9 400000E 01 FIINIT S80 6 000000E 02 FIINIT S97 1 001000E 10 FIINIT ENUL 1 001000E 10 FIINIT BLOK 1 000000E 00 FIINIT PRPS 1 000000E 00 FIINIT DEPO 1 001000E 10 FIINIT EMIS 0 000000E 00 FIINIT VPOR 1 000000E 00 FIINIT RHO1 1 001000E 10 FIINIT TEM1 2 930000E 02 No PATCHes used for this Group INIADD F Group 12 Convection and diffusion adjustments No PATCHes used for this Group Group 13 Boundary Special Sources PATCH RELT PHASEM 1 1 1 21 1 23 1 1 COVAL RELT S177 GRND1 SAME COVAL RELT S80 GRND1 SAME COVAL RELT S97 GRND1 SAME EGWF F Group 14 Downstream Pressure For PARAB Group 15 Terminate Sweeps LSWEEP 200 RESFAC 1 000000E 06 Group 16 Terminate Iterations Group 17 Relaxation RELAX P1 LINRLX 1 000000E 00 RELAX V1 FALSDT 1 000000E 03 RELAX W1 FALSDT 1 000000E 03 RELAX S80 FALSDT 1 000000E 02 RELAX S97 FALSDT 1 000000E 02 RELAX TEM1 LINRLX 7 000000E 01 Group 18 Limits VARMAX P1 1 000000E 10 VARMIN P1 1 064000E 02 VARMAX V1 1 000000E 06 VARMIN V1 1 000000E 06 VARMAX W1 1 000000E 06 VARMIN W1 1 000000E 06 VARMAX S177 1 000000E 00 VARMIN S177 1 000000E 20 VARMAX S80 1 000000E 00 VARMIN S80 1 000000E 20 VARMAX S97 1 000000E 00 VARMIN S97 1 000000E 20 VARMAX TEM1 3 000000E 03 VARMIN TEM1 2 600000E 02 Group 19 EARTH Calls To GROUND Station USEGRD T USEGRX T NAMGRD CVD S2SR T ASAP T PARSOL T CSG10 q1 SPEDAT SET CVD VOLIN L F SPEDAT SET CVD MCDOPT I 2 SPEDAT SET CVD BINOPT I 4 SPEDAT SET CVD MCPROP I 3 SPEDAT SET CVD CHMRLX R 5 00000E 01 SPEDAT SET CVD NSREAC I 1 SPEDAT SET CVD SREAC 1 I 17 SPEDAT SET CVD XMIR L F SPEDAT SET CVD YMIR L F SPEDAT SET CVD ZMIR L F SPEDAT SET CVD AXIBFC L F SPEDAT SET CVD NOSPCT L F SPEDAT SET CVD FINE3D L F SPEDAT SET CVD VFNORM L T SPEDAT SET CVD NUMRAY I 1 SPEDAT SET CVD RADCVD L T SPEDAT SET CVD OPTTEM R 3 28000E 02 SPEDAT SET CVD OPTMAT R 1 11000E 02 SPEDAT SET CVD EXTBOU C TEMPERATURE SPEDAT SET CVD EXTTEM R 3 28000E 02 Group 20 Preliminary Printout ECHO T Group 21 Print out of Variables Group 22 Monitor Print Out IXMON 1 IYMON 19 IZMON 29 NPRMON 100000 NPRMNT 1 TSTSWP 1 Group 23 Field Print Out Plot Control NPRINT 100000 ISWPRF 1 ISWPRL 100000 No PATCHes used for this Group Group 24 Dumps For Restarts GVIEW P 9 819036E 01 1 200022E 01 1 465084E 01 GVIEW UP 1 195696E 01 9 927558E 01 1 178796E 02 DOM SIZE 1 000000E 01 1 570000E 01 1 689980E 01 DOM MONIT 5 000000E 02 1 052967E 01 1 535078E 01 DOM SCALE 1 000000E 00 1 000000E 00 1 000000E 00 DOM SNAPSIZE 1 000000E 02 GRID AUTO T T T GRID MINCELL 5 000000E 03 1 000000E 01 1 000000E 01 GRID RSET X 1 1 1 000000E 00 GRID RSET Y 1 13 1 200000E 00 G GRID RSET Y 2 4 1 200000E 00 G GRID RSET Y 3 6 1 200000E 00 G GRID RSET Y 4 4 1 200000E 00 G GRID RSET Y 5 6 1 200000E 00 G GRID RSET Y 6 4 1 200000E 00 G GRID RSET Z 1 8 1 200000E 00 G GRID RSET Z 2 8 1 200000E 00 G GRID RSET Z 3 5 1 200000E 00 G GRID RSET Z 4 8 1 200000E 00 G GRID RSET Z 5 2 1 200000E 00 G GRID RSET Z 6 4 1 200000E 00 G OBJ NAME BLK1 OBJ POSITION 0 000000E 00 0 000000E 00 1 549980E 01 OBJ SIZE 1 000000E 01 1 020000E 01 1 400001E 02 OBJ GEOMETRY polcu7 OBJ ROTATION24 1 OBJ TYPE BLOCKAGE OBJ MATERIAL 154 USRM2 OBJ FIXED TMP 0 000000E 00 7 330000E 02 OBJ INI BLOK 2 000000E 00 OBJ SUF REAC L YES OBJ BATCH F L 1 000000E 00 OBJ NAME BLK1A OBJ POSITION 0 000000E 00 1 020000E 01 1 549980E 01 OBJ SIZE 1 000000E 01 1 500000E 02 1 400001E 02 OBJ GEOMETRY polcu8 OBJ ROTATION24 1 OBJ TYPE BLOCKAGE OBJ MATERIAL 154 USRM2 OBJ INI BLOK 3 000000E 00 OBJ SUF REAC L YES OBJ BATCH F L 1 000000E 00 OBJ NAME BLK2 OBJ POSITION 0 000000E 00 9 500000E 02 0 000000E 00 OBJ SIZE 1 000000E 01 6 199999E 02 4 999999E 02 OBJ GEOMETRY polcu7 OBJ ROTATION24 1 OBJ TYPE BLOCKAGE OBJ MATERIAL 198 Solid with smooth wall friction OBJ SURF TEMP S 0 000000E 00 3 280000E 02 OBJ SURF TEMP H 0 000000E 00 3 280000E 02 OBJ NAME BLK3 OBJ POSITION 0 000000E 00 0 000000E 00 9 700000E 02 OBJ SIZE 1 000000E 01 1 470000E 01 2 599999E 02 OBJ GEOMETRY polcu8 OBJ ROTATION24 1 OBJ TYPE BLOCKAGE OBJ MATERIAL 111 STEEL at 27 deg c C 1 OBJ INI BLOK 4 000000E 00 OBJ NAME BLK4 OBJ POSITION 0 000000E 00 1 290000E 01 1 230000E 01 OBJ SIZE 1 000000E 01 1 799999E 02 3 599799E 02 OBJ GEOMETRY polcu8 OBJ ROTATION24 1 OBJ TYPE BLOCKAGE OBJ MATERIAL 111 STEEL at 27 deg c C 1 OBJ INI BLOK 5 000000E 00 OBJ NAME INLET OBJ POSITION 0 000000E 00 0 000000E 00 1 230000E 01 OBJ SIZE 1 000000E 01 1 020000E 01 0 000000E 00 OBJ GEOMETRY polcu5t OBJ ROTATION24 1 OBJ TYPE INLET OBJ DENSITY 1 700000E 03 OBJ VELOCITY 0 000000E 00 0 000000E 00 4 035000E 00 OBJ TEMPERATURE 2 930000E 02 OBJ INLET S80 6 000000E 02 OBJ OBJECT SIDE HIGH OBJ NAME OUT OBJ POSITION 0 000000E 00 0 000000E 00 0 000000E 00 OBJ SIZE 1 000000E 01 9 500000E 02 0 000000E 00 OBJ GEOMETRY polcubet OBJ ROTATION24 1 OBJ TYPE OUTLET OBJ PRESSURE 0 000000E 00 OBJ TEMPERATURE SAME OBJ COEFFICIENT 1 000000E 03 OBJ VELOCITY 0 000000E 00 SAME SAME OBJ OUTLET S80 SAME OBJ OUTLET S97 SAME OBJ NAME FLOOR OBJ POSITION 0 000000E 00 1 170000E 01 1 689980E 01 OBJ SIZE 1 000000E 01 3 999999E 02 0 000000E 00 OBJ GEOMETRY polcu2 OBJ ROTATION24 1 OBJ TYPE PLATE OBJ SURF TEMP 0 000000E 00 3 280000E 02 OBJ NAME WALL OBJ POSITION 0 000000E 00 1 570000E 01 4 999999E 02 OBJ SIZE 1 000000E 01 0 000000E 00 1 189980E 01 OBJ GEOMETRY polcu2 OBJ ROTATION24 1 OBJ TYPE PLATE OBJ SURF TEMP 0 000000E 00 3 280000E 02 OBJ NAME B15 OBJ POSITION 0 000000E 00 0 000000E 00 1 549980E 01 OBJ SIZE 1 000000E 01 1 020000E 01 0 000000E 00 OBJ GEOMETRY polcusrf OBJ ROTATION24 1 OBJ TYPE RAD SURF OBJ OBJECT SIDE HIGH OBJ SETTING AUTO OBJ TEMP COEF GRND1 OBJ OPTIC INDX 1 540000E 02 OBJ OPTIC TEMP 7 330000E 02 OBJ NAME B16 OBJ POSITION 0 000000E 00 1 170000E 01 1 549980E 01 OBJ SIZE 1 000000E 01 0 000000E 00 1 400000E 02 OBJ GEOMETRY polcusrf OBJ ROTATION24 1 OBJ TYPE RAD SURF OBJ SETTING AUTO OBJ TEMP COEF GRND1 OBJ OPTIC INDX 1 540000E 02 OBJ OPTIC TEMP 7 330000E 02 OBJ NAME B17 OBJ POSITION 0 000000E 00 1 020000E 01 1 549980E 01 OBJ SIZE 1 000000E 01 1 500001E 02 0 000000E 00 OBJ GEOMETRY polcusrf OBJ ROTATION24 1 OBJ TYPE RAD SURF OBJ OBJECT SIDE HIGH OBJ SETTING AUTO OBJ TEMP COEF GRND1 OBJ OPTIC INDX 1 540000E 02 OBJ OPTIC TEMP 7 330000E 02 OBJ NAME B18 OBJ POSITION 0 000000E 00 9 500000E 02 0 000000E 00 OBJ SIZE 1 000000E 01 0 000000E 00 4 999999E 02 OBJ GEOMETRY polcusrf OBJ ROTATION24 1 OBJ TYPE RAD SURF OBJ SETTING AUTO OBJ SURF TEMP 3 280000E 02 OBJ OPTIC INDX 1 110000E 02 OBJ OPTIC TEMP 3 280000E 02 OBJ NAME B19 OBJ POSITION 0 000000E 00 9 500000E 02 4 999999E 02 OBJ SIZE 1 000000E 01 6 200001E 02 0 000000E 00 OBJ GEOMETRY polcusrf OBJ ROTATION24 1 OBJ TYPE RAD SURF OBJ OBJECT SIDE HIGH OBJ SETTING AUTO OBJ SURF TEMP 3 280000E 02 OBJ OPTIC INDX 1 110000E 02 OBJ OPTIC TEMP 3 280000E 02 OBJ NAME B20 OBJ POSITION 0 000000E 00 1 470000E 01 9 700000E 02 OBJ SIZE 1 000000E 01 0 000000E 00 2 599999E 02 OBJ GEOMETRY polcusrf OBJ ROTATION24 1 OBJ TYPE RAD SURF OBJ SETTING AUTO OBJ TEMP COEF GRND1 OBJ OPTIC INDX 1 110000E 02 OBJ OPTIC TEMP 4 400000E 02 OBJ NAME B21 OBJ POSITION 0 000000E 00 0 000000E 00 9 700000E 02 OBJ SIZE 1 000000E 01 1 470000E 01 0 000000E 00 OBJ GEOMETRY polcusrf OBJ ROTATION24 1 OBJ TYPE RAD SURF OBJ OBJECT SIDE HIGH OBJ SETTING AUTO OBJ TEMP COEF GRND1 OBJ OPTIC INDX 1 110000E 02 OBJ OPTIC TEMP 4 400000E 02 OBJ NAME B22 OBJ POSITION 0 000000E 00 1 290000E 01 1 230000E 01 OBJ SIZE 1 000000E 01 0 000000E 00 3 599801E 02 OBJ GEOMETRY polcusrf OBJ ROTATION24 1 OBJ TYPE RAD SURF OBJ OBJECT SIDE HIGH OBJ SETTING AUTO OBJ TEMP COEF GRND1 OBJ OPTIC INDX 1 110000E 02 OBJ OPTIC TEMP 4 400000E 02 OBJ NAME B23 OBJ POSITION 0 000000E 00 1 470000E 01 1 230000E 01 OBJ SIZE 1 000000E 01 0 000000E 00 3 599801E 02 OBJ GEOMETRY polcusrf OBJ ROTATION24 1 OBJ TYPE RAD SURF OBJ SETTING AUTO OBJ TEMP COEF GRND1 OBJ OPTIC INDX 1 110000E 02 OBJ OPTIC TEMP 4 400000E 02 OBJ NAME B24 OBJ POSITION 0 000000E 00 1 290000E 01 1 589980E 01 OBJ SIZE 1 000000E 01 1 800001E 02 0 000000E 00 OBJ GEOMETRY polcusrf OBJ ROTATION24 1 OBJ TYPE RAD SURF OBJ SETTING AUTO OBJ TEMP COEF GRND1 OBJ OPTIC INDX 1 110000E 02 OBJ OPTIC TEMP 4 400000E 02 OBJ NAME B25 OBJ POSITION 0 000000E 00 1 170000E 01 1 689980E 01 OBJ SIZE 1 000000E 01 4 000000E 02 0 000000E 00 OBJ GEOMETRY polcusrf OBJ ROTATION24 1 OBJ TYPE RAD SURF OBJ SETTING AUTO OBJ SURF TEMP 3 280000E 02 OBJ OPTIC INDX 1 110000E 02 OBJ OPTIC TEMP 3 280000E 02 OBJ NAME B26 OBJ POSITION 0 000000E 00 1 570000E 01 4 999999E 02 OBJ SIZE 1 000000E 01 0 000000E 00 1 189980E 01 OBJ GEOMETRY polcusrf OBJ ROTATION24 1 OBJ TYPE RAD SURF OBJ SETTING AUTO OBJ SURF TEMP 3 280000E 02 OBJ OPTIC INDX 1 110000E 02 OBJ OPTIC TEMP 3 280000E 02 OBJ NAME B27 OBJ POSITION 0 000000E 00 0 000000E 00 0 000000E 00 OBJ SIZE 1 000000E 01 9 500000E 02 0 000000E 00 OBJ GEOMETRY polcusrf OBJ ROTATION24 1 OBJ TYPE RAD SURF OBJ SETTING AUTO OBJ SURF TEMP 3 280000E 02 OBJ OPTIC INDX 1 110000E 02 OBJ OPTIC TEMP 3 280000E 02 OBJ NAME B28 OBJ POSITION 0 000000E 00 0 000000E 00 1 230000E 01 OBJ SIZE 1 000000E 01 1 290000E 01 0 000000E 00 OBJ GEOMETRY polcusrf OBJ ROTATION24 1

    Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_docs/tr314/tr314-a2.htm (2016-02-15)
    Open archived version from archive

  • TR211: GENTRA User Guide Chapter 1
    the continuous phase e Melting solidifying particles f Vaporising droplets GENTRA will automatically detect internal walls and obstacles and provides options for a Particle bouncing with a user specified restitution coefficient b Particle adhesion to the wall c Withdrawal of the particle d Flash vaporisation of the particle if the particle is a droplet c In respect of post processing GENTRA can generate input files for the PHOENICS post processors VR Viewer PHOTON and Autoplot For VR Viewer and PHOTON it generates trajectory files which record the trajectory of the particle as it moves through the domain For Autoplot it generates history files which record the evolution of the particle properties with time Limitations of GENTRA As well as capabilities GENTRA has also limitations Appendix A of this guide provides a list of the main limitations known to the GENTRA Development Team at CHAM The contents of the list changes as known limitations are removed and new ones found An updated list of the limitations affecting your version of GENTRA if different from the one described in this manual is available through the GENTRA Input Menu Help and information panel See Section 2 4 of this Guide for details How GENTRA fits in Section 1 1 above classified GENTRA as a PHOENICS add on The present section describes in more detail how GENTRA is related to the rest of PHOENICS GENTRA has a pre processing and a processing part which are dealt with in the following sub sections Pre processing The pre processing part involves the preparation of the GENTRA input which consists of particle data solution control data and output control data It can be accomplished in several alternative ways a By using the GENTRA Input Menu b By using a set of special PIL commands the GENTRA PIL c By loading a case from the GENTRA Input Library The pre processing side of GENTRA uses the general PHOENICS VR environment For the benefit of experienced PHOENICS users it will be pointed out here that all the GENTRA information is sent from the Q1 file to EARTH through the transfer arrays RG IG LG and CG Processing The processing part of GENTRA takes the form of a collection of FORTRAN subroutines which are attached to the PHOENICS flow computing program EARTH GENTRA which solves the equations for the disperse phase is called by PHOENICS between the sweeps of the computational domain that PHOENICS performs to solve the continuous phase GENTRA then tracks the particles as they move through the computed flow field calculating in the process the interphase interactions i e the transfer of momentum mass enthalpy etc between the phases These interaction terms are after leaving GENTRA incorporated as sources in the continuous phase equations for the next PHOENICS sweep Since the newly introduced sources are likely to alter the flow field used by GENTRA to track the particles in the first instance several iterations of the processes PHOENICS sweep GENTRA tracking will normally be needed to obtain

    Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_docs/tr211/chap1.htm (2016-02-15)
    Open archived version from archive

  • TR211: GENTRA User Guide Chapter 2
    and pressure gradient effects The option brings up the menu panel displayed in figure 2 8 Figure 2 8 Gravity buoyancy X Y Z component of gravity vector Use these options to specify the three components of the gravitational acceleration acting on the particles The components of the gravitational acceleration must be supplied in the GENTRA Cartesian System regardless of the co ordinate system being employed for the continuous phase See entry in the GENTRA glossary for a description of the GENTRA Cartesian System Enter 9 8 for Z component of gravity vector to specify an acceleration of 9 8 m s 2 acting along the z axis Force on particle due to buoyancy This option activates deactivates the buoyancy formulation When active it introduces a multiplicative factor 1 r c r p in the gravity term of the particle momentum equation See Section 6 3 2 for details Force on particle due to pressure gradient This option activates deactivates the pressure gradient term in the particle momentum equation see Section 6 3 2 for details If P1 includes the hydrostatic pressure then the user selects pressure gradient term to active and buoyancy term to not active to include all the fluid forces on the particle or pressure gradient term to not active and the buoyancy term to active to include only buoyancy If P1 excludes the hydrostatic pressure reduced pressure formulation then the user should select pressure gradient term to active and buoyancy term to active to include all fluid forces on the particle pressure gradient term to not active and buoyancy term to active to include only buoyancy Data for heat exchanging particles Figure 2 9 Data for heat exchanging particles The selection of drag coefficient is identical to that for the case of isothermal particles see subsection c above for a complete explanation Thermal conductivity of continuous phase This option must be selected A value of 0 0263 W m k is given as the default corresponding to air at STP If the user wishes to include his own temperature dependent function for the thermal conductivity of the continuous phase he should do the following 1 Replace the constant value in the menu with a GRND number i e GRND1 2 Modify function routine GPROPS in the file GENTRA FTN by adding coding in the relevant section For this case the coding should be added in the section commencing GROUND1 and in the subsection commencing 3 Thermal Conductivity of the continuous phase Coding relating the thermal conductivity GPROPS to the continuous phase temperature PARAMT should then be inserted 3 Before running EARTH the GENTRA file will have to be recompiled and the EARTH executable relinked The Nusselt number is defaulted to GRND1 This implies that the Nusselt number will be calculated from the correlation of equation 6 8 other correlations may be included in GPROPS following a procedure similar to that outlined above for the setting of the continuous phase thermal conductivity Alternatively the Nusselt number may immediately be specified as a constant during this menu session The specific heat capacity of the particle is defaulted to 4131 8 J kg k which is representative of liquid water Other constant values can be substituted for this or it can be replaced by a particle temperature dependent function in GPROPS A constant value of 1007 J kg k is provided as the default value for the specific heat capacity of the continuous phase this being the value for air at STP The constant value can be altered during the menu session or a temperature dependent function can be implemented using the techniques mentioned above Gravity and buoyancy pressure gradient effects and turbulent dispersion can be included the reader is referred to the entries in sub sections c and a above for an explanation Data for melting solidifying particles Figure 2 10 Data for melting solidifying particles The data required for melting solidifying particles is as follows Drag coefficient see Subsection c for explanation Thermal conductivity of continuous phase The default value of 0 0263 is for air at STP Nusselt number see Subsection d for explanation Cp of liquid phase of the melting solidifying particle The value of 4131 8 is representative of water Cp of solid phase of the melting solidifying particle Cp of continuous phase Latent heat of solidification The default value of 3 335E 05 is for the formation of water ice If the specific heat capacities of the liquid and solid phases were not identical and if the change of phase was not isothermal the latent heat of solidification would be temperature dependent and a function would be required for it in GPROPS Further explanation of this is provided in Section 6 3 4 Index for solid fraction formula equation 6 15 For the case of isothermal phase change this variable is not employed Solidus temperature of particle The maximum temperature at which the particle is completely in the solid phase The default value is for water Liquidus temperature of particle The minimum temperature at which the particle is completely in the liquid phase The default value is for water Gravity buoyancy pressure forces See Subsection c above for this option Stochastic turbulence model See Subsection a above for details on this option The constant values which appear in this menu can be replaced with functions set in function routine GPROPS according to the method described in Subsection c above Data for vaporising droplets Figure 2 11 Data for vaporising droplets Drag coefficient See Subsection c for explanation Nusselt number See Subsection d for explanation Cp of Continuous phase The default value of 1007 is for air at STP Cp of Vapour The value of CV is defaulted to GRND1 which directs control to GPROPS where a temperature dependent property is specified Cp of Particle The default value of 4131 8 is for water Latent heat of evaporation A saturation temperature dependent function for the latent heat of evaporation is provided as the default value GRND1 The function is for water vapour and is derived from curve fits on steam tables Particle liquid saturation enthalpy The default value of GRND1 produces a temperature dependent function for the liquid saturation enthalpy of water based on curve fits from steam tables Saturation temperature of vapour The default value of GRND1 provides a function for the saturation temperature of water vapour as a function of pressure Saturation pressure of vapour The default value of GRND1 provides the temperature dependent vapour pressure correlation of Bain 1964 Thermal conductivity of continuous phase The default value of 0 0263 is for air at STP Thermal conductivity of vapour The default value of GRND1 provides a temperature dependent function for water vapour based on curve fits to steam tables Molecular weight of continuous phase defaulted to air 28 9 Molecular weight of particle phase defaulted to water 18 0 Minimum particle diameter The minimum size of particle below which the particle is assumed to have completely evaporated Gravity buoyancy pressure forces See Subsection c above for details on this option Stochastic turbulence model See Subsection a above for details on this option This option appears on the next panel reached by clicking Page down or Line down The constant values which appear in this menu can be replaced with functions set in function routine GPROPS according to the method described in Subsection c above Boundary conditions for particles The Boundary conditions button in the Main Menu panel figure 2 2 is used to specify the boundary conditions for the particles Boundary conditions fall into the following categories Inlets The injection position and the particle properties eg velocities diameter temperature etc at the inlet must be given Exits The boundary regions at which the particles can leave the domain must be specified Symmetry surfaces The location of the symmetry surfaces at which particles must be reflected must be supplied Wall obstacles The behaviour of the particle following the collision with a wall or obstacle is selected from a range of choices such as bouncing sticking or flash vaporisation Click on Boundary conditions to bring up the Boundary conditions panel Figure 2 12 Boundary conditions for particles The options in the Boundary conditions panel shown in figure 2 12 are dealt with in subsequent subsections Inlet conditions The Inlet conditions option of the Boundary conditions panel produces the panel in figure 2 13 Figure 2 13 Particle inlet conditions Inlet data file name The inlet data in GENTRA is specified in a table located in an inlet data file The user can select the name of the inlet data file through this option the maximum length of the file name is 4 characters Further information on the contents and format of the inlet data can be found at the end of this sub section The default file name Q1 will be used for the worked example Coordinate system for Positions Option not available in the present version of GENTRA This option allows the specification of inlet co ordinates in the inlet file in either the GENTRA Cartesian system see glossary entry for a definition or in the grid system The distinction is only relevant to cylindrical polar grids since in Cartesian and BFC the GENTRA Cartesian system and the grid system coincide At present the particle positions must be specified in the grid co ordinate system Thus for cylindrical polar grids the co ordinates are specified as r z The alignment between the Cartesian and polar grid systems is explained in Appendix H Coordinate system for Velocities Option not available in the present version of GENTRA This option allows the specification of inlet velocities in the inlet file in either the GENTRA Cartesian system see glossary entry for a definition or in the grid system The distinction is only relevant to cylindrical polar and BFC grids since in Cartesian grids the velocity components in the GENTRA Cartesian system and in the grid system are the same At present all inlet velocities must be specified in the Cartesian co ordinate system in the order Ucrt Vcrt Wcrt where these represent the velocity components in the Cartesian X y and Z directions respectively For cylindrical polar grids the order of specification is Vcrt Ucrt and Wcrt Format and contents of the inlet data table Inlet data In the inlet data table each parcel of particles has a data line the data required is case dependent For the user s guidance the GENTRA menu will generate as a comment in the resulting Q1 file a suitable heading for the inlet table The contents of the inlet table are also provided below for the different particle types Particle Properties required Lazy POSTN Stubborn POSTN VELOC Isothermal POSTN VELOC DIAM DENSTY FRATE NUMB Heat exchanging POSTN VELOC DIAM DENSTY FRATE TEMP NUMB Melt solidifying POSTN VELOC DIAM LIQDEN FRATE TEMP SOLDEN NUMB Vaporising POSTN VELOC DIAM DENSTY FRATE TEMP NUMB In the table above POSTN is the parcel inlet position in the co ordinate system selected by the user for one or two dimensional cases no co ordinates are needed for the dimensions for which the number of cells are one VELOC is the parcel inlet velocity components in the co ordinate system selected by the user for one or two dimensional cases no components are needed for the dimensions in which the number of cells are one DIAM is the particle diameter DENSTY is the density of the particle LIQDEN is the density of the liquid phase in solidifying particles Units kg m3 FRATE is the mass flow rate of particles Units kg s TEMP is the particle temperature in K SOLDEN is for melting solidifying particles the solid phase density NUMB is an optional parameter indicating the number of parcels of the given characteristics to be released from that position When the stochastic turbulence model is active GENTRA will track every parcel separately When the stochastic turbulence model is inactive GENTRA will simply multiply the mass flow rate by the number of parcels and track a single parcel When the NUMB data item is missing one parcel is assumed Comments Those lines in the inlet table containing in any position an asterisk are treated as comments The table heading can be inserted in this way in the data file Blank lines are also ignored Line length The maximum length of an inlet table line is 132 characters Number formatting The formatting of the numbers in the inlet table is free but items of data must be separated with spaces commas or semi colons Error trapping GENTRA will skip those data lines that contain invalid characters such as letter O instead of number zero or that have a different number of data items to that which is required Q1 file as input file By setting the inlet data file name to Q1 the default GENTRA will expect the inlet data table to be in the Q1 file All of the format rules for the inlet data table listed above apply to the Q1 file In addition when the inlet data table is in the Q1 file the following practices must be observed Inlet data lines must be PIL comments i e they must not start in the first or second column of the Q1 file since they would be treated as commands by the SATELLITE The inlet data table must be preceded and terminated by two special marks also inserted as PIL comments These marks are GENTRA INLET DATA and END GENTRA INLET respectively WARNING The maximum length of the inlet data line is 132 characters However users are advised that the maximum length of a Q1 file line for the SATELLITE is 68 characters if the SATELLITE is run after the inlet data has been inserted and following instructions from the user the Q1 file is re written all the data items in columns 68 onwards will be lost The inlet data table can be located anywhere in the Q1 file and is normally written using a system file editor after the menu session Note GENTRA can generally cope with inlets lying exactly on the boundaries of the domain or on the grid pole it is nevertheless a good practice to offset the inlet position by a small distance e g 10 4 m In this worked example we will write the data table after finishing the menu session Editing the File Containing the Input Data Table In the VR Environment the file containing the inlet data table can be opened for editing by clicking on File Open file for editing If the inlet data table is in Q1 select Q1 and then click Yes to save the current settings to Q1 After editing the inlet data table save the file and exit the editor Click Yes to reload the Q1 into VR Editor otherwise the new data will be lost To open any other file select Any file then open it from within the editor The editor used can be selected from Options Text file editor Exits Particle exits in GENTRA are represented through PATCH commands Particle exit PATCHes must have names beginning with GX and be of an area type ie EAST WEST NORTH SOUTH HIGH LOW In the VR Environment all Inlet and Outlet objects act as GENTRA exits by default the PATCHes they create all have names starting with GX This behaviour can be altered by the Acts as GENTRA exit buttons at the foot of the Inlet and Outlet object attribute dialogs Note that these buttons only appear once GENTRA is active The buttons can be seen in Figure 2 14 Figure 2 14 Inlet and Outlet attribute dialogs To create an exit where only particles can leave the domain set the coefficient for the pressure to zero in the Outlet attributes dialog This will prevent the continuous phase from passing through Symmetry surfaces The treatment for particles at an axis surface of symmetry is always reflection i e bouncing with a restitution coefficient of 1 regardless of the wall treatment selected for the problem GENTRA will automatically detect symmetry axes in the following two circumstances In 2D cylindrical polar cases and 3D cylindrical polar cases in which the domain covers less than 2 p radians in the circumferential direction the grid pole is treated as an axis of symmetry In wedge like 2D BFC domains in which one of the domain sides collapses to a line the edge of the wedge is treated as a symmetry axis In all other cases axes surfaces of symmetry must be declared by the user so that GENTRA can act appropriately when a particle hits the axis surface Symmetry surfaces in GENTRA are represented through PATCH commands whose PATCH name starts with GS Each symmetry PATCH has also an associated PATCH type This indicates on which face of the cells covered by the PATCH the symmetry surface is The PATCH type can be EAST WEST NORTH SOUTH HIGH or LOW In the VR Environment GENTRA symmetry surfaces are created by making a new object with type GENTRA SYMMETRY This object type is only available when GENTRA is active The PATCH created by such an object will have a name starting with GS and will be of the correct type The grid in the worked example is of the wedge like kind the axis will therefore be automatically detected by GENTRA Wall obstacle treatment The option Wall obstacle treatment in the Boundary conditions panel figure 2 12 specifies how the particle interacts with walls and obstacles e g bouncing sticking removal See the GENTRA Glossary for a definition of wall obstacle The options available depend on the type of particle the user is therefore advised to set the particle type before visiting this menu The panel in figure 2 15 shows all of the possible treatments Figure 2 15 Wall obstacle treatment The menu Wall obstacle treatment has in the general case the following options

    Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_docs/tr211/chap2.htm (2016-02-15)
    Open archived version from archive

  • TR211: GENTRA User Guide Chapter 3
    line GENTR T It is this setting which tells EARTH that GENTRA is active GENTRA Groups 1 to 4 GENTRA data This part of the Q1 file see Appendix E for an example carries the problem definition settings It comprises four groups which are the same as those appearing in the main panel of the GENTRA menu see figure 2 2 namely Group 1 Particle physics Group 2 Particle boundary conditions Group 3 Numerical controls Group 4 Input Output controls Settings in these groups are effected by assigning values to the GENTRA PIL variables A list of these variables and where appropriate the acceptable range of values can be found in Appendix B GENTRA Group 2 can also carry optionally the inlet data table See Section 2 7 1 for details Provisions for the EARTH run In addition to performing the data specification for the disperse phase the GENTRA Menu will also make a number of provisions for GENTRA EARTH such as the allocation of auxiliary storage space or the set up of interphase sources The provisions made by the GENTRA Menu depend on the dimensionality of the problem the grid type the continuous phase variables that are being solved for and the particle type The settings will be found in Groups 7 13 and 17 of the Q1 file A complete list of the actions undertaken by the GENTRA Menu can be found below for the user s reference a If the grid is a BFC one and the continuous phase Cartesian velocity components UCRT VCRT WCRT have not been STOREd a STORE command will be issued GENTRA uses the Cartesian velocity component for the integration of the particle momentum equations b For BFC grids NCRT ie the sweep frequency for the calculation of the Cartesian components in a is set to 1 c 3D storage space is allocated through STORE commands for the following quantities MOMX MOMY MOMZ the interphase sources of momentum Not stored for lazy and stubborn particles HEAT the interphase source of heat stored if the particle is exchanging heat with the continuous phase MASS the interphase source of mass stored if the particle is exchanging mass with the continuous phase d The variable VAPO representing the vapour mass fraction in the continuous phase for vaporising droplets is SOLVEd for if appropriate and its PRANDTL numbers PRNDTL VAPO laminar and PRT VAP0 turbulent are assigned according to the menu settings e If the calculation of cell residence time for a particle has been requested 3D storage is allocated for the variable REST through a STORE command f PATCHes and COVALs are generated for the interphase sources as follows PATCH GENPAT CELL 0 0 0 0 0 0 1 LSTEP COVAL GENPAT U1 FIXFLU GRND COVAL GENPAT V1 FIXFLU GRND COVAL GENPAT W1 FIXFLU GRND COVAL GENPAT H1 FIXFLU GRND COVAL GENPAT VAPO FIXFLU GRND g For vaporising droplets PATCHes and COVALs are generated for the interphase source of mass as follows PATCH GENMAS CELL 0

    Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_docs/tr211/chap3.htm (2016-02-15)
    Open archived version from archive

  • TR211: GENTRA User Guide Chapter 4
    transient problem has been reached h The tracking of the particle was aborted by GENTRA Results produced by GENTRA The information provided by GENTRA falls into the following categories a Progress and error information printed on the screen b Information in the RESULT file and c Information in special data files These three categories are dealt with in the next subsections Screen information During the GENTRA EARTH run a message will be written to the screen when the track for a particle starts and another message will flag the end of the tracking and inform of the particle fate Between the beginning and end of track flags the following information is provided on the screen Number of time steps for the particle Average number of time steps per cell and Minimum maximum and average size of the time step Error and warning messages are also routed by GENTRA to the screen All the output described in this section can be re directed to a file see Chapter 5 and Section C 3 for details The RESULT file GENTRA itself does not print any information in the RESULT file but the following PHOENICS quantities provided by EARTH are related to GENTRA calculations a The values of MOMX MOMY MOMZ are the interphase sources of momentum for each cell b the values of HEAT are the cell values of the interphase source of heat for heat exchanging particles c the values of MASS are the cell values of the interphase source of mass for mass exchanging particles and d if the computation of particle cell residence times is requested by the user these will be found for each cell under the variable REST Special data files Two special sets of files can be generated by GENTRA one for the particle trajectories and

    Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_docs/tr211/chap4.htm (2016-02-15)
    Open archived version from archive



  •  


web-archive-uk.com, 2017-12-17