Search **web-archive-uk.com**:

Find domain in archive system:

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". |

- PHOENICS-CVD

reactors this involves the modeling of fluid flow and heat transfer in a multi component gas including both gas phase homogeneous and surface heterogeneous chemical reactions and incorporating plasma effects Implementation is by means of a graphical menu driven object orientated interface coupled with a library of generic reactor designs providing an easy route to problem set up and modification PHOENICS CVD offers Simulation of steady state or transient process start up and shut down behavior in Cartesian polar or BFC grids Multi component diffusion and gas properties with a choice of models Thermal diffusion with a choice of options Gas and surface chemical reactions with built in options and the provision for user coding if required Surface to surface radiation Plasma modelling using an effective drift diffusion model Data files for transport thermodynamic material optical and chemical reaction parameters Platform independence ability to run on PCs MS Windows LINUX workstations UNIX and VAX and supercomputers Application examples PHOENICS CVD has been used to simulate Silicon nitride formation in a hot wall batch reactor Tungsten deposition in a single wafer cold wall reactor Polysilicon growth in an RTP reactor Plasma enhanced deposition of amorphous silicon Polysilicon single wafer reactor processes

Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_phoen/cvd.htm (2016-02-15)

Open archived version from archive - CHEMKIN.HTM

fraction of the species xx eg STORE MH2 for the SOLVEd hydrogen species H2 The mole fractions Xi are calculated from Xi Yi W Wi where W is the mixture molecular mass and Wi is the molecular mass of species i 7 Model Setup In order to ease the setup of models employing the CHEMKIN interface a SATLIT code CHEMST and two PIL fragments have been supplied Prior to calling CHEMST the user should where appropriate set the value of CSG4 to identify LINK files with non default names set the value of CHSOB the index of the 1st CHEMKIN variable set the value of CHSOA to determine the solution algorithm issue the commands STORE TEM1 or SOLVE TEM1 set the variable CHSOA GRND9 to use the implicit PBP solver set any CHEMK source PATCHes needed When called the routine CHEMST does the following it reads the CHEMKIN appropriate CHEMKIN link file CKLINK or xxxxckln it sets up dependent variables for the CHEMKIN species it sets COVALs for any CHEMK source PATCHes it sets VARMIN and VARMAX values for species and if appropriate for the temperature if the implicit PBP solver is selected it makes settings of RESREF and ENDIT values that are roughly appropriate it returns the number of species in the CHEMKIN scheme in the variable CHSOD it returns the finallised location of the first CHEMKIN variable in the variable CHSOB 9 Developments and modifications CONTENTS 9 1 Developments 9 2 Modifications Made to CHEMKIN Routines 9 1 Developments There are a number of areas in which work remains to be done and these are Turbulent combustion nothing has been done because the modelling of turbulent combustion is still poorly understood and so it is not clear which model should be adopted or how useful such a model

Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_enc/chemkin.htm (2016-02-15)

Open archived version from archive - CONSERVATIVE LOW-DISPERSION ALGORITHM

greater than can be achieved by the equivalent conventional refinement which in three dimensions would multiply by eight the number of rectangular cells The superiority results from the way in which the convection fluxes across the sub cells are computed c The convection fluxes The computation of the convection fluxes will be explained by reference to a two dimensional grid in the north south east west i e plane Let the west east mass fluxes be FW and FE Let the south north mass fluxes be FS and FN Then the continuity satisfying CLDA assumption is that the flux from We to w is FW the flux from Sn to s is FS the flux from s to w is FS FW 2 the flux from s to e is FS FE 2 the flux from w to n is FW FN 2 the flux from w to s is FW FS 2 and so on The fluxes across the diagonal faces are therefore deduced from those across the vertical and horizontal ones by simple formulae These fluxes like those across the horizontal and vertical cell walls are assumed to carry the values of the scalar which prevail on their upwind sides d Consequences When the fluxes FS and FW are equal which implies that the direction of fluid flow is along the south west to north east diagonal the above formulae imply no transfer of either mass or convected scalar across that diagonal There is therefore no numerical diffusion On a conventional rectangular grid as is well known the upwind scalar value assumption results in substantial numerical diffusion in such an along diagonal flow The CLDA will exhibit its worst numerical diffusion for flows directed along lines bisecting the angles between the diagonals and the rectangular sides but its

Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_enc/conserv.htm (2016-02-15)

Open archived version from archive - CO-LOC.HTM

use the discretised momentum equations for the two neighbouringnodes as the interpolation formulae but replace the terms representing pressure gradient across the cell face by one which is centered about it An example below will clarify this procedure On the non staggered grid nodal velocity say U are represented as sum ai Ui p Pw Pe Su p Up Ap u 2 12 aP p aP p aP p In the method considered the linear interpolation is still used to obtain the interface cell face velocities Substituting the last equations in arithmetic mean formulae we have sum ai Ui p Su p sum ai Ui E Su E Ue 0 5 aP p aP E Pw Pe Pe PeE 0 5 Ap u AE u aP p aP E 2 13 The key idea is to replace the last two terms in RHS of this equation by one which contain the pressure at the node P in an explicit manner namely 1 1 0 5 Pp PE Ae u 2 14 aP p aP E This modification provides the required pressure velocity coupling Pp PE Ue He Ae u 2 15 aP e where sum ai Ui p Su p sum ai Ui E Su E He 0 5 aP p aP E and 1 1 1 0 5 aP e aP p aP E 2 16 Similar equations can be derived for other cell face velocities Then they can be used to calculate mass fluxes for finite difference coefficients Now by adding linear pressure interpolation for calculation of pressure force differences the set of momentum equations is closed and can be solved to get nodal velocities 2 5 3 Summary of the Rhie and Chow algorithm The technique just described divides the calculations of the cell face velocities in the stages as follows Calculate the pressure gradient coefficient distribution as a reciprocal of left hand side coefficient of 2 4 i e PGCp 1 sum ai SP 2 17 Calculate the pressure free velocities Hp sum Ui ai SU PGCp 2 18 In 2 17 2 18 SP and SU contain the contributions of all sources except pressure differences Calculate the cell face velocities by difference equations assembling linearly interpolated pressure gradient coefficients and pressure free velocities together with actual pressure force differences on both sides of the face in question i e for uniform grid spacing Ue Hp HE 2 PGCp PGCE 2 Pp PE Au e 2 19 Vn Hp HN 2 PGCp PGCN 2 Pp PN Av n 2 20 Wh Hp HH 2 PGCp PGCH 2 Pp PH Aw h 2 21 Then the mass fluxes needed for Up Vp and Wp calculations are easily followed by linear interpolation of pressures for their differences as for uniform grid 2 10 2 6 Solution procedure The co located velocity component conservation equations are solved using the standard PHOENICS solver as normal scalar variables at the cell centres As outlined above additional sources are added To solve

Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_enc/co-loc.htm (2016-02-15)

Open archived version from archive - COMMAND.HTM

of command file Test command file first read some data DATA 1 1 DATA 1 2 DATA 1 3 Now plot each curve separately PLOT 1 PAUSE DOT 2 PAUSE DOT2 3 PAUSE END In this file the first three commands read data elements from a PLOT file The program then draws each curve in a different line style with a pause between each curve so that the picture can be viewed When Return is pressed the program plots the next curve and then PAUSEs again The END in a command file causes an exit from AUTOPLOT if END is omitted control is returned to the interactive mode and the prompt Command appears Only one USE file may be in use at a time therefore a USE command cannot be issued from within a USE file Command session recording A macro making facility is now available by means of a new command that records the interactive command session in a file The file can subsequently be read as a USE file to reproduce automatically the command sequence For further information see the entry LOG in the PHOTON help dictionary COMMANDS in the PHOENICS Input Language PIL see the entry COMMANDS hlp1 The following commands were added to PIL or modified with PHOENICS version 1 5 INLET NAME TYPE IXF IXL IYF IYL IZF IZL ITF ITL OUTLET NAME TYPE IXF IXL IYF IYL IZF IZL ITF ITL WALL NAME TYPE IXF IXL IYF IYL IZF IZL ITF ITL VALUE NAME PHI VALUE SUBGRD DIR L1 L2 DIST POW LIBLIST keyword1 keyword2 keywordn DUMP ARRAY d1 d2 lt d3 LOCATE ARRAY VALUE IP SORT ARRAY FUNC IMAX GETPTC NAME TYPE IXF IXL IYF IYL IZF IZL ITF ITL GETCOV NAME PHI CO VAL GETSOL PHI CT1 CT2 CT3 CT4 CT5 CT6

Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_enc/command.htm (2016-02-15)

Open archived version from archive - CONJUG.HTM

harmonic averaging of the exchange coefficients specify the locations of the solids by the use of CONPOR with a negative blockage factor and create the thermal link between solid and fluid by activating the automatic wall functions on the solid surfaces see CONPOR specify the material in each cell by store prps followed by appropriate initialisation of PRPS with FIINIT and patch statements Convergence of the TEm1 equation may be accelerated by specifying whole field solution for TEM1 see SOLUTN and by using the block correction technique described in the entry on BLOK An example of conjugate heat transfer may be found in Library case 460 As compared with the conjugate heat transfer capability of PHOENICS 1 5 the current PHOENICS is improved several respects An ASCII file houses now the library of materials which can therefore be easily customised expanded by the user Material properties can now be constant or dependent on other properties They can also be read from Q1 directly by EARTH Boundary conditions including thermal links at the fluid solid interface are set up automatically Heat transfer coefficients can be optionally calculated and printed out by Earth Conjugate heat transfer in the general menu A new

Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_enc/conjug.htm (2016-02-15)

Open archived version from archive - CONTOUR.HTM

OF f element range switches off the specified contour element s It will not appear in subsequent plots until switched on again See also CONTOUR ON CONTOUR ON Photon Help CON tour ON element range switches on the specified contour element s It will then appear in subsequent plots See also CONTOUR OFF Contour options You can use the DASH and COLOUR options for CONTOUR plots Other options for CONTOUR include SHADE and FILL Contour range specification of After you issue a CONTOUR command you need to specify to PHOTON the range of values to be plotted and the number of intervals you require in this range There are four ways in which you can provide this information by specifying the upper and lower bounds of the range and the number of intervals into which the range is to be subdivided eg 1 0 2 0 10 the numbers being separated by spaces by INT n which specifies the use of n contour intervals equally spaced over either the field range or the plane range and so generates n 1 contours The SET CONTOUR SCALE command enables you to select which range is used by VAL n which prompts for n individual contour values or by OLD which signifies that the previous contour range and intervals are to be used An example of a complete contour command is Command con p1 Ix 1 IY 1 7 Whole field range of values is 0 1 to 10 44 Plane range of values is 0 1 to 10 44 Range and number of intervals INT 12 which plots over part of the IX 1 plane 12 equally spaced contour levels of P1 over the whole range of pressures The following alternative response to the second prompt Range and number of Intervals VAL

Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_enc/contour.htm (2016-02-15)

Open archived version from archive - CONVEC.HTM

sixth character of the patch name is the letter D then it signifies the choise of the one of the local oscillation damping algorithms i e SOLD or CDLD depending on the GRNDn number in the value argument of the COVAL command as will be explained in the next section The letter C in the sixth character of the patch name determines the CSOB scheme to be used In the latter case two different PATCH es with the names ending with C0 and C4 followed by corresponding COVAL commands must be specified for each variable ii Patch type The patch type must be CELL iii Extent The extent of the patch does not need to be the whole computational domain but will determine the region over which the scheme is applied Note that convection terms are modified only over the cell surfaces internal to the patch The COVAL command has the general format COVAL CONM phi FIXFLU GRNDn where i phi is a scalar variable ii The GRNDn number in the value argument determines the scheme to be used according to the following table Value PATCH name Scheme GRND CONM Implicit SOUD GRND4 CONM Implicit CDS GRND4 CONM D Implicit

Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_enc/convec.htm (2016-02-15)

Open archived version from archive

web-archive-uk.com, 2017-12-16