Files

• Input Data File (.dat)
• Grid File (.cgd)
• Flow File (.cfl)
• Boundary Data File (.tda)
• Time History File (.cth)
• List Output File (.lis)
• Time Data File (.cft)
• Edge Data File (.cge)
• Wind-US Control File (WINDCTRL)
• Wind-US Stop File (NDSTOP)
• Temperature and Transition Specification Files
• Chemistry Files (.chm)
• Turbomachinery Data Files
• Memory Log File (memdebug.lis)
• Reserved Files

A number of files are used by Wind-US in the course of a solution. The script file you run to submit Wind-US jobs will assign all the necessary files to their appropriate Fortran unit numbers, so you should not need to do any of that yourself. Each of the support files is described briefly below.

Input Data File (.dat)

The input data file is the primary control file for Wind-US and must be created for each case you want to run with the code. Input data and code options are entered in this file through the use of descriptive keywords. You should observe the following formatting rules in creating the input data file:

1. The first three lines of the file are reserved for geometry, flow condition, and arbitrary titles, respectively. Each of these titles may be up to 64 characters long. None of these first three lines may start with the (case-insensitive) word "Include".
   
   
2. Blank lines and comments, beginning with a "/" or "!" character, may be placed anywhere in the file after the first three lines. Both dedicated comment lines and trailing comments are supported. Data file readability may be improved dramatically through the liberal use of comments - for example, separating logical sections of the data file: numerical algorithm, force integrations, test options, etc.
   
   
3. Block data, such as that specified in arbitrary inflow or chemistry cases, must be contiguous. Only keywords corresponding to the block may reside between the beginning and ending block indicators (e.g., CHEMISTRY and ENDCHEMISTRY).
   
   
4. Keywords may be entered in upper or lower case.
   
   
5. Abbreviations for keywords may be used, as long as they are unique. If they are not, you may not get the results you expect. For example, it's not a good idea to use single-letter abbreviations for keywords.
   
   
6. The input data file may include content from other files through the use of the INCLUDE keyword.

The following is an example of a simple input data file:

   Geometric Title
   Flowfield Condition Title
   Optional Title

   !-- Freestream "static" conditions:  Mach, p(psi), T(R), alpha(deg), beta(deg)
   Freestream static 0.9 14.7 530. 4. 0.

   !-- Specify turbulence model
   Turbulence Model Inviscid

   !-- Specify how long to run
   Cycles 15

   End

A copy of the input data file will be written as character data in the root node of the flow file (.cfl). This data can be read with the cflinfo utility.

Grid File (.cgd)

The computational grid used by Wind-US for a particular case is stored in the grid file. In this file are stored the (x, y, z) coordinates of all computational grid points, zone coupling interpolation factors, and grid reference and scaling data.

This file was originally referred to as the common grid file, so named because the file was formatted according to Boeing's Common File Format (CFF). Wind-US also supports grid files in CGNS (CFD General Notation System)format. [Detailed information on the CGNS standard may be found at the CGNS web site .] Both common files and CGNS files are binary, and portable to virtually every hardware platform, except Cray, with no need for explicit data conversions.

Grid files for Wind-US may be created by several mesh-generation codes in either common file or CGNS format. If necessary, the cfcnvt utility may be used to convert a variety of other formats, including PLOT3D xyz format, to common file format.

Zone coupling, reference, and scaling data are added to common grid files using the GMAN program. Common grid files are also used in the CFPOST post-processing package. Neither GMAN nor CFPOST currently support CGNS files, however.

Even when third-party mesh-generation codes are used to create the grid file, GMAN or MADCAP should still be used to perform grid quality checks and confirm that no boundary surface condition remains undefined. Often zone coupling information, particularly for non-point-matched boundaries, is missing from the file.

Keywords: CGNSBASE

Flow File (.cfl)

The flow file contains the computed flow field. For Navier-Stokes and Euler solutions, the file contains density, momentum, and energy data, and, for viscous solutions, turbulence data. The flow file also records the current solution cycle number to allow the file to be used for solution restarts.

Like the grid file, the flow file was originally referred to as the common flow file, but may now be written in either common file or CGNS format. Several graphical post-processing programs are able to read both common files and CGNS files.

The CFPOST post-processing package may be used with common flow files to produce other files for post-processing and/or to create flowfield plots directly. CFPOST does not currently support CGNS files, however.

Keywords: CGNSBASE

Boundary Data File (.tda)

Wind-US's boundary data file is used during solution restarts, and results in smoother restarts, especially with higher-order boundary coupling. The file acts as a buffer for the transfer of zone coupling information and a holding bin for data needed throughout a Wind-US run but not stored in the grid or solution file.

Time History File (.cth)

The time history file is a common file which stores data resulting from the use of Wind-US's history tracking capability. The file contains a lookup table corresponding to the range of computational indices tracked during the run, time stamp data, and flowfield data for each time stamp. Upon completion of a time history run, the auxiliary program thplt may be used to view the contents of the time history file.

Keywords: HISTORY

List Output File (.lis)

The purpose of Wind-US's list output file is to echo the input from the input data file, track convergence and integration results, record CPU/job statistics, and log code error messages. The auxiliary program resplt may be used to extract convergence and integration data from the list output file and create a GENPLOT-style data file, which may be plotted with the plot command in the CFPOST post-processing package. For parallel-processing runs, this file also contains messages relating to the PVM system and to the allocation and operation of slave processors. Convergence data is written to this file for each of the equation sets solved during the run, including the Euler, Navier-Stokes, and non-algebraic turbulence model sets.

Time Data File (.cft)

The time data file may be used for storing the computed flow field at the extra time levels required for second-order time differencing, Newton iteration, and/or dual time stepping. Currently by default, the extra time levels for second-order time differencing are stored in the .cfl file, and those for Newton iteration and dual time stepping are stored in the .cft file and linked to the .cfl file. Keywords in the TEMPORAL keyword block may be used to specify where the extra time levels should be stored.

Keywords: IMPLICIT ORDER, NEWTON, TEMPORAL

Edge Data File (.cge)

The edge data file is used with unstructured grids to store grid-related information about each cell that's required during the solution procedure. The file is created during the initial run, and by default is saved for use in subsequent restart runs, but will be recreated if it's missing. When the file is opened, if necessary it is automatically split into multiple files to keep the size of each file below two gigabytes, with the main file transparently linked to the separate files.

Keywords: DEBUG 8, DEBUG 9

Wind-US Control File (WINDCTRL)

The control file can be used to modify certain program inputs while the code is running. This is particularly useful on large cluster machines, since small changes can be made without having to stop the job, edit the input (.dat) file, resubmit it, and wait in the queue to run again.

At the beginning of every cycle, the program checks for the WINDCTRL control file. If it exists, the file is opened, checked for recognized commands, and then deleted. Note that the control file must be placed in the directory where the code is running, and that this directory may be different from the one where the wind command was issued. If the -runinplace option to the wind script is not used, the job will be run in a remote directory. The root name of the remote run directory may be specified using the -runroot option, or in response to a command line prompt. The default for the root name of the remote directory is /tmp. The full name of the remote directory will be rootname/userid/basename.scr, where rootname is the root name described above, userid is your userid, and basename is the base name of your .dat file.

Below are the keywords that the control file supports:

Wind-US Stop File (NDSTOP)

The stop file is used to stop Wind-US execution cleanly in the middle of a CFD solution. Although a solution may be stopped simply by killing the Wind-US process from the system queue, doing so will not ensure a clean update of all zonal flowfield data to the flowfield file. The stop file - named NDSTOP - provides a means to cleanly shut down a running solution, completing the current cycle or zone, performing zone coupling, updating the flowfield file, and removing all symbolic links to Fortran file unit numbers.

To stop the code, you must place one of two words in the stop file in the directory in which the Wind-US job is running. The word STOP in the stop file signals Wind-US to complete the current cycle (at the end of the last zone) and exit. In single-processing mode, you may also use the word STOPZONE in the stop file to stop Wind-US after completing the zone currently in memory. [In multi-processing mode, STOPZONE does the same thing as STOP.] You may then restart the code in your next run, starting at the next zone or back at zone one. Regardless of the existence of this file, Wind-US will stop if the requested number of cycles has been computed, or if your solution has converged.

During the clean-up procedure at the end of the job, the NDSTOP file is automatically removed.

Note that the directory in which the Wind-US job is running, where the NDSTOP file must be, is not necessarily the one you were in when the wind command was issued. If you don't use the -runinplace option to the wind script, the job will be run in a remote directory. The root name of the remote run directory may be specified using the -runroot option, or in response to a command line prompt. The default for the root name of the remote directory is /tmp. The full name of the remote directory will be rootname/userid/basename.scr, where rootname is the root name described above, userid is your userid, and basename is the base name of your .dat file.

On a Unix system, you might submit a simple "at" job for a later time as follows:

   at 0530 monday
   echo STOP > NDSTOP
   ^D

At 5:30 AM on the next Monday, the system would create the NDSTOP file with the word "STOP" in it. Note that this will not stop the run exactly at 5:30 AM; Wind-US must still complete the current cycle, which may take an hour or more for large cases.

Keywords: RESTART

Temperature and Transition Specification Files

Wind-US can read temperature and transition files, specifying the temperature or transition to turbulence on any boundary surface, that were created with the older tmptrn utility. This option is included for backward compatibility with WIND 2.0, and is only needed for an initial (i.e., non-restart) run. The wind script copies the files to the run directory, and Wind-US opens the files directly (unit 45) using the file names specified with the TTSPEC keyword. New applications should use the latest tmptrn utility to write the temperature/transition data into the flow (.cfl) file directly.

Keywords: TTSPEC

Chemistry Files (.chm)

The generalized chemistry files contain all the information Wind-US requires to compute a general chemistry mixture. A chemistry file has a header line, followed by three sections containing data defining the thermodynamic properties, reaction rates, and transport properties.

Header

The first line in the file must contain a single value, ispec, specifying the type of reaction and the format for the finite-rate data. The format for the line is:

   ispec     ISPEC

(The value ispec is read using a list-directed read statement. The ISPEC label following the value is thus optional, but present in the standard chemistry files supplied with Wind-US. The labels following the values ns, nreq, ndeq, and tfrmin, described in the next two sections, are also optional.)

It should be noted that ispec values of 1, 3, and 4 were used in earlier versions of Wind-US. Values of 1 and 4 are now equivalent to ispec = 100, and 3 is now equivalent to ispec = 130.

Thermodynamic Properties

This section of the chemistry data file contains the information necessary to compute the thermodynamic properties for each species. The general format for this section is:

   THERMODYNAMIC COEFFICIENTS
   Title, line 1
   Title, line 2
   ns     NS
   Curve type
   Information defining species 1
   ...
   Information defining species ns

The information defining each species, and the specific format used, depends on the curve type, as described below.

SPARKCRV

[Note - Because the SPARKCRV format lacks information needed to correctly calculate entropy, it is now considered obsolete and may not be supported in the future. Test 19 must be active to use this format. Users are encouraged to use the NASA3287 format instead.]

This is the original file format used for Wind-US chemistry files. The specific heat at constant pressure C_p for each species is defined by a series of fourth-order polynomials, each valid within a defined temperature range. I.e.,

where R is the universal gas constant, and T is in K.

Given the above, polynomials may be derived for the enthalpy, entropy, and Gibbs free energy.

For the SPARKCRV curve type, the enthalpy reference state is at T = 0 K. I.e., the curve fit for H/RT actually computes

where Δ_fH₍₀₎ is the heat of formation at 0 K, and ΔH_(0→T) is the change in enthalpy between 0 K and T.

For each species, the information defining the species and for computing C_p / R, etc., is stored in the .chm file as described in the following table. Note that records 2-3 are repeated for each temperature range.

Example

THERMODYNAMIC COEFFICIENTS
 FROM NASA-RFL-TR-70-3, NASA-CR-111989, MAC LIB FISH NO. N71-38747

    5      NS
SPARKCRV
O2                 3    O  2.   0.   0.   0.             3.5         32.000
        300.000       1000.000    0.37190E+01   -0.25170E-02    0.85840E-05
   -0.83000E-08    0.27080E-11  -0.104419E+04    0.00000E+00
       1000.000       6000.000    0.33160E+01    0.11510E-02   -0.37260E-06
    0.61860E-10   -0.36660E-14  -0.104419E+04    0.00000E+00
       6000.000      15000.000    0.37210E+01    0.42540E-03   -0.28350E-07
    0.60500E-12   -0.51860E-17  -0.104419E+04    0.00000E+00
NO                 3    O  1.N  1.   0.   0.             3.5         30.008
        300.000       1000.000    0.41470E+01   -0.41200E-02    0.96920E-05
   -0.78630E-08    0.22310E-11   0.979001E+04    0.00000E+00
       1000.000       6000.000    0.32210E+01    0.12210E-02   -0.42970E-06
    0.65590E-10   -0.34510E-14   0.979001E+04    0.00000E+00
       6000.000      15000.000    0.38450E+01    0.25210E-03   -0.26580E-07
    0.21620E-11   -0.63810E-16   0.979001E+04    0.00000E+00
... etc.

WINDNASA

[Note - Because the WINDNASA format lacks information needed to correctly calculate entropy, it is now considered obsolete and may not be supported in the future. Test 19 must be active to use this format. Users are encouraged to use the NASA3287 format instead.]

This is the same as the SPARKCRV curve fits described above, except for the addition of a single final record for each species that specifies the heat of formation at 0 K. The same equations are used for C_p/R, etc. However, with the WINDNASA curve fits, the enthalpy (and Gibbs free energy, since G/RT = H/RT − S/R) use an enthalpy reference state of 298.15 K instead of 0 K. I.e., the curve fit for enthalpy actually computes

where Δ_fH₍₂₉₈₎ is the heat of formation at 298.15 K, and ΔH_(298→T) is the change in enthalpy between 298.15 K and T.

In Wind-US, when ADJUST is specified in the CHEMISTRY keyword block, the values of enthalpy and Gibbs free energy returned by the WINDNASA curve fits are shifted to change the reference state to 0 K. I.e.,

When ADJUST is specified, Δ_fH₍₀₎, the heat of formation at 0 K in the above equation, is read from the .chm file. If ADJUST is not specified, the enthalpy reference state is left as 298.15 K, and the line in the .chm file containing the heat of formation at 0 K, if present, is ignored.

For each species, the information defining the species and for computing C_p / R, etc., is stored in the .chm file as described in the following table. Note that records 2-3 are repeated for each temperature range. Except for the last record specifying the heat of formation at 0 K, this is the same as for the SPARKCRV format.

Example

THERMODYNAMIC COEFFICIENTS
 CURVE FITS FROM NASA LEWIS CET86 HIGH TEMPERATURE THERMO DATA BASE

    7      NS
WINDNASA
O2                 2    O  2.   0.   0.   0.             3.5         31.998
        300.000       5000.000  3.1162949E+00  1.5886094E-03 -6.7904360E-07
  1.4714899E-10 -1.1729212E-14 -9.9401794E+02  6.4600671E+00
       5000.000      15000.000  2.5782323E+00  8.5796324E-04 -7.6397647E-08
  1.3412616E-12  3.2564804E-17  1.1504711E+03  1.1400551E+01
Heat of Formation at 0 deg K    0.0
H                  2    H  1.   0.   0.   0.             2.5          1.008
        300.000       5000.000  2.5000000E+00  0.0000000E+00  0.0000000E+00
  0.0000000E+00  0.0000000E+00  2.5474038E+04 -4.5991986E-01
       5000.000      15000.000  2.5000000E+00  0.0000000E+00  0.0000000E+00
  0.0000000E+00  0.0000000E+00  2.5474038E+04 -4.5991986E-01
Heat of Formation at 0 deg K    216024.1
... etc.

NASA3287

This format for the curve fits defining the thermodynamic properties is derived from the one defined in NASA TP-3287. [McBride, B. J., Gordon, S., and Reno, M. A. (2001) "Thermodynamic Data for Fifty Reference Elements," NASA TP-3287/REV1.] A series of curves is again used to define the specific heat at constant pressure, enthalpy, entropy, and Gibbs free energy, with each curve valid within a defined temperature range. I.e.,

where R is the universal gas constant, and T is in K.

Like the WINDNASA curve fits, the enthalpy reference state for the NASA3287 curve fits is 298.15 K. When ADJUST is specified in the CHEMISTRY keyword block, the values of enthalpy and Gibbs free energy are shifted to change the reference state to 0 K, as described above for the WINDNASA curve fits.

For each species, the information defining the species and for computing C_p / R, etc., is stored in the .chm file as described in the following table. Note that records 3-5 are repeated for each temperature range.

Example

THERMODYNAMIC COEFFICIENTS
 CURVE FIT JANAF 6000K DATA EXTRAP. TO 15000K & NASA LEWIS DATA RE-FITTED

    5      NS
NASA3287
CO2               Props & Hf298: TPIS v2,pt1,1991,p27.
 3 l 7/88 C   1.00O   2.00    0.00    0.00    0.00 0     44.00980    -393510.000
    200.000  1000.000 7 -2.0 -1.0  0.0  1.0  2.0  3.0  4.0  0.0         9365.469
  4.94378364D+04 -6.26429208D+02  5.30181336D+00  2.50360057D-03 -2.12470010D-07
 -7.69148680D-10  2.84997991D-13  0.00000000D+00 -4.52818986D+04 -7.04876965D+00
   1000.000  6000.000 7 -2.0 -1.0  0.0  1.0  2.0  3.0  4.0  0.0         9365.469
  1.17696943D+05 -1.78880147D+03  8.29154353D+00 -9.22477831D-05  4.86963541D-09
 -1.89206384D-12  6.33067509D-16  0.00000000D+00 -3.90834501D+04 -2.65268192D+01
   6000.000 20000.000 7 -2.0 -1.0  0.0  1.0  2.0  3.0  4.0  0.0         9365.469
 -1.54440594D+09  1.01683595D+06 -2.56137666D+02  3.36936340D-02 -2.18115756D-06
  6.99132366D-11 -8.84221052D-16  0.00000000D+00 -8.04312703D+06  2.25415288D+03
Heat of Formation at 0 deg K    -393149.56
H2O               CODATA,1989. JRNBS v92,1987,p35. TRC tuv-25,10/88.
 2 l 8/89 H   2.00O   1.00    0.00    0.00    0.00 0     18.01528    -241826.000
    200.000  1000.000 7 -2.0 -1.0  0.0  1.0  2.0  3.0  4.0  0.0         9904.092
 -3.94795999D+04  5.75572977D+02  9.31783351D-01  7.22271091D-03 -7.34255448D-06
  4.95504134D-09 -1.33693261D-12  0.00000000D+00 -3.30397425D+04  1.72420539D+01
   1000.000  6000.000 7 -2.0 -1.0  0.0  1.0  2.0  3.0  4.0  0.0         9904.092
  1.03497224D+06 -2.41269895D+03  4.64611114D+00  2.29199814D-03 -6.83683007D-07
  9.42646842D-11 -4.82238028D-15  0.00000000D+00 -1.38428625D+04 -7.97815119D+00
Heat of Formation at 0 deg K    -238918.95
... etc.

Reaction Rates

This section of the .chm file contains the reaction rate information. The first five lines are:

   FINITE RATE COEFFICIENTS
   Title, line 1
   Title, line 2
   nreq ndeq     NREQ, NDEQ
   tfrmin        TFRMIN

There are three possible formats for the remainder of this section, depending on the value of ispec.

Format 1; ispec = 100, 110, 115

This option may be used for any chemically reacting flow with dissociation and exchange reactions of the form

where S₁, etc., represent chemical species.

Rate Equations

For dissociation reactions, the forward and backward reaction rate equations are of the form

where [S₁] represents the concentration of species S₁, etc.

For exchange reactions, the forward and backward reaction rate equations are of the form

Rate Coefficients

The forward and backward reaction rate coefficients k_f and k_b are computed using the equations

For ispec = 100 or 110, the equilibrium constant K is computed using

For ispec = 115 the equilibrium constant K is computed from the change in Gibbs free energy for the reaction. I.e.,

where ΔG^o is the change in Gibbs free energy, R is the gas constant, and T is the temperature. The Gibbs free energy for each species is determined from the information specified in the Thermodynamic Properties section.

Third Body Reaction Rates

For the dissociation reactions the specification of the third body reaction rates depends on the ispec value used.

File Format

The information needed for each reaction is stored in the chemistry data (.chm) file, with the dissociation reactions listed first. I.e., reaction data is specified in the following order:

   Information defining dissociation reaction 1
   ...
   Information defining dissociation reaction ndeq
   Information defining exchange reaction 1
   ...
   Information defining exchange reaction nreq - ndeq

The data to be specified in the .chm file is described in detail in the following table.

   THIRD [BODY] [EFFICIENCY] nnot1

   species(1)  efficiency(1)
   ...
   species(nnot1)  efficiency(nnot1)

   THIRD [BODY] [EFFICIENCY] nnot1

With Format 1, the data is read in subroutine frtin1, and the rates are computed in rates (for ispec = 100), ratesa (ispec = 110), or ratesadl (ispec = 115).

Example

FINITE RATE COEFFICIENTS
 FROM AIAA 88-0513

    5,3      NREQ,NDEQ
  2000.      TFRMIN
O2              O       O         -1.0       5.9500E+04
   1.335      -4.127      -0.616       0.093      -0.005       5
                O2       2.75E+19
                NO       2.75E+19
                O        8.25E+19
                N        8.25E+19
                N2       2.75E+19
N2              N       N         -1.6       1.1320E+05
   3.898     -12.611       0.683      -0.118       0.006       5
                O2       3.70E+21
                NO       3.70E+21
                O        1.11E+22
                N        1.11E+22
                N2       3.70E+21
NO              N       O         -0.5       7.5500E+04
   1.549      -7.784       0.228      -0.043       0.002       5
                O2       2.30E+17
                NO       2.30E+17
                O        4.60E+17
                N        4.60E+17
                N2       2.30E+17
NO      O       O2      N          1.29      1.9220E+04
   0.215      -3.652       0.843      -0.136       0.007       0
                         2.16E+08
O       N2      NO      N          0.1       3.7700E+04
   2.349      -4.828       0.455      -0.075       0.004       0
                         3.18E+13

Format 2; ispec = 130, 135, 136, 137

This format is the most flexible one in Wind-US, with a variety of options for specifying the necessary information. "Elementary" dissociation and exchange reactions may be specified using ispec = 130, 135, and 136, the same as with Format 1. In addition, for ispec = 137, "general" and "global" exchange reactions may be specified with up to three reactants and products.

Rate Equations

General exchange reactions are of the form

Global exchange reactions are forward only, of the form

Rate Coefficients

For all the ispec values, the forward and backward reaction rate coefficients k_f and k_b are computed using the equations

Note that unlike Format 1, with Format 2 the backward reaction rate coefficient k_b may be specified independently of the forward reaction rate coefficient. However, if the specified input value of either the forward or backward coefficient C_f or C_b is zero, the corresponding reaction rate coefficient k_f or k_b is computed from the non-zero reaction rate coefficient and an equilibrium constant that's computed using Gibbs function, just as in Format 1 with ispec = 115. E.g., if the specified C_b = 0, the backward reaction rate coefficient is computed as

Eddy Dissipation Concept

For ispec = 137, the eddy dissipation concept may be used, specified using the EDC keyword in the CHEMISTRY keyword block. Note that although three reactants and products are allowed with ispec = 137, the eddy dissipation concept should only be used with two reactants and forward reactions only, and is only applicable to non-premixed combustion. It's intended for rapid combustion reactions with the fuel as species S₁ and the oxidizer as species S₂.

With the eddy dissipation concept, a second forward reaction rate is computed in addition to the one described above. The two reaction rates are compared, and the lower rate is used.

The reaction rate equation using the eddy dissipation concept is of the form

where C_edc is the eddy dissipation coefficient, specified using the EDC keyword in the CHEMISTRY keyword block; ρ is the fluid density; M₁ and M₂ are the molecular weights of species 1 (fuel) and species 2 (oxidizer); C_μ is a constant equal to 0.09; ω is the specific dissipation rate from the SST turbulence model; [S₁] and [S₂] are the concentrations of species 1 (fuel) and species 2 (oxidizer); and c₁ and c₂ are the number of molecules in the reaction for species 1 (fuel) and species 2 (oxidizer).

Note that the eddy dissipation concept may currently be used only with the SST turbulence model.

Damkohler Rate Limiter

Also for ispec = 137, the Damkohler rate limiter may be used, specified using the DAMKOHLER keyword in the CHEMISTRY keyword block.

With the Damkohler limiter, both forward and backward reaction rates are limited such that the ratio Da = τ_FD / τ_CH is less than some user-specified maximum Da_max. The fluid dynamic time scale τ_FD is taken as the local time step Δt. The chemical reaction time scale τ_CH is the value that would allow the concentration of the specie with the smallest negative defect (i.e., the one that will first reach zero concentration) to drop by a ratio of 1/e.

Third Body Reaction Rates

Like in Format 1, for the dissociation reactions the specification of the third body reaction rates depends on the ispec value used.

File Format

The information needed for each reaction is stored in the chemistry data (.chm) file, with the dissociation reactions listed first. I.e., reaction data is specified in the following order:

   Information defining dissociation reaction 1
   ...
   Information defining dissociation reaction ndeq
   Information defining exchange reaction 1
   ...
   Information defining exchange reaction nreq - ndeq

First, for each of the dissociation reactions, the .chm file contains the following:

   THIRD [BODY] [EFFICIENCY] nnot1

   species(1)  efficiency(1)
   ...
   species(nnot1)  efficiency(nnot1)

Following the data for the dissociation reactions, the .chm file contains the data for each of the exchange reactions. If ispec = 137, this section begins with an optional line containing either the word GENERAL or GLOBAL. I.e.,

   [GENERAL | GLOBAL]

If ispec = 137, and GENERAL or GLOBAL is specified, general or global exchange reactions with up to three reactants and three products are used, and the data for each reaction is specified as follows:

   {STOICHIOMETRIC | EXPONENTS}

   a  b  c  d  e  f

With Format 2, the data is read in subroutine frtin3, and the rates are computed in ratesbe.

Example

FINITE RATE COEFFICIENTS
 FROM EVAN & SCHEXNAYDER - CONVERTED TO EQUILIBRIUM CONSTANT FORM

    8,4      NREQ,NDEQ
   300.      TFRMIN
O2   1.         O    1. O    1.   -1.0       5.9340E+04   7.20E+18
                                  -1.0       0.0          4.00E+17
H2   1.         H    1. H    1.   -1.0       5.1987E+04   5.50E+18
                                  -1.0       0.0          1.80E+18
H2O  1.         OH   1. H    1.   -1.5       5.9386E+04   5.20E+21
                                  -1.5       0.0          4.40E+20
OH   1.         O    1. H    1.   -1.0       5.0830E+04   8.50E+18
                                  -1.0       0.0          7.10E+18
O2   1. H    1. OH   1. O    1.    0.0       8.4550E+03   2.20E+14
                                   0.0       0.0          1.50E+13
H2   1. O    1. OH   1. H    1.    0.0       5.5860E+03   7.50E+13
                                   0.0       4.4290E+03   3.00E+13
H2O  1. O    1. OH   1. OH   1.    0.0       9.0590E+03   5.80E+13
                                   0.0       5.0300E+02   5.30E+12
H2O  1. H    1. OH   1. H2   1.    0.0       1.0116E+04   8.40E+13
                                   0.0       2.6000E+03   2.00E+13

Format 3; ispec = 120, 121

[Note - This format is considered obsolete, and may be removed in the future. The same capability is available using Format 2 with ispec = 137.]

This option is only for global 1- or 2-reaction chemistry, and only for forward reactions. It is a quick method for simulating detonation problems, for example, in which reactions proceed only forward to completion. It allows dissociation and exchange reactions of the form

Rate Equations

For dissociation reactions, the reaction rate equation is of the form

Rate Coefficient

The reaction rate coefficient k is computed using the equation

where T is the temperature in K, the ratio D/K_B is in K, and K_B is the Boltzmann constant. The reaction rate coefficient for the j'th reaction, C_j, has units (cm³/g-mol)^O_j−1 (sec-K^S)⁻¹, where O_j is the order of the reaction (i.e., the total number of moles of reactants).

Eddy Dissipation Concept

For ispec = 121, the eddy dissipation concept may be used, as described above for Format 2 with ispec = 137.

File Format

The information needed for each reaction is stored in the chemistry data (.chm) file in the following order:

   Information defining reaction 1
   ...
   Information defining reaction nreq

The data to be specified in the .chm file is described in detail in the following table.

With Format 3, the data is read in subroutine frtin2, and the rates are computed in ratesf (for ispec = 120) or ratesg (for ispec = 121).

Example

FINITE RATE COEFFICIENTS
WESTBROOK-DREYER GLOBAL REACTION MODEL 

    1,0      NREQ,NDEQ
   250.      TFRMIN
C2H4 1. O2   3. CO2  2. H2O  2.    0.0       1.5098E+04
   0.0         0.0         0.0         0.0         0.0         0
0.10    1.65             2.00E+12

Transport Properties

This section of the chemistry data file contains the information used to compute the laminar viscosity and thermal conductivity. The formulation is based on Wilke's law, with either Sutherland's law or a NASA four-coefficient formula used individually for each species. Different constants or coefficients may be specified for different temperature ranges.

For Sutherland's law, the equations are of the following form:

For the NASA formula, the equations are [Svehla, R. A. (1995) "Transport Coefficients for the NASA Lewis Chemical Equilibrium Program," NASA TM-4647]:

The data is read from the chemistry data file, in the following form:

   TRANSPORT COEFFICIENTS [NASA]
   Title, line 1
   Title, line 2
   Information for species 1
   ...
   Information for species ns

When Sutherland's law is used, the information for each species is stored in the .chm file as described in the following table. The reference viscosity μ₀ is in millipoise; the reference conductivity k₀ is in BTU/(hour-ft-°R); the reference temperatures and temperature offsets are in °R; and the beginning and ending temperatures for each curve are in K. Note that records 3 and 4 are repeated, in pairs, for each temperature range after the first. I.e., the Sutherland's law constants for both μ and k are listed for the first curve, followed by the constants for both μ and k for the second curve, etc.

When the NASA formula is used, the format for the information in the .chm file is as described in the following table. With the NASA formula, the viscosity μ is in micropoise, the thermal conductivity k is in microwatts/(cm-K), and the beginning and ending temperatures for each curve are in K. Note that record 2 is repeated for each viscosity temperature range, followed by record 3 repeated for each thermal conductivity temperature range. I.e., the coefficients for all the μ curves are listed first, followed by the coefficients for all the k curves.

If the effective binary diffusion model is being used (specified by the the DIFFUSION EFFECTIVE-BINARY keyword in the CHEMISTRY keyword block), the Lennard-Jones parameters [Lennard-Jones, J. E. (1924) "On the Determination of Molecular Fields. I. From the Variation of the Viscosity of a Gas with Temperature," Proc. of the Royal Society, A106, pp. 441-462; Lennard-Jones, J. E. (1924) "On the Determination of Molecular Fields. II. From the Equation of State of a Gas,'' Proc. of the Royal Society, A106, pp. 463-477] used to compute the effective binary diffusivity for each species must also be included in the .chm file, following the TRANSPORT COEFFICIENTS data described above. Values for these parameters for a variety of species may be found in the literature (e.g., Bird, R. B., Stewart, W. E., and Lightfoot, E. N. (1960) Transport Phenomena, John Wiley & Sons, New York.)

The data is read in the following form:

   LENNARD-JONES PARAMETERS
   Title, line 1
   Title, line 2
   Parameters for species 1
   ...
   Parameters for species ns

For each species, the data is read using the format described below. The parameter σ is in angstroms, and ε/K_B is in degrees Kelvin.

Example

TRANSPORT COEFFICIENTS


O2            1   300.000 15000.000   1.9190E-01  4.9160E+02  2.5000E+02
                                      1.4190E-02  4.9160E+02  4.0000E+02
NO            1   300.000 15000.000   1.3700E-01  4.9160E+02  4.0000E+02
                                      8.4070E-03  4.9160E+02  4.0000E+03
O             1   300.000 15000.000   1.7030E-01  7.5000E+02  1.5500E+03
                                      1.0360E-02  4.9160E+02  2.3000E+03
N             1   300.000 15000.000   1.7890E-01  4.9160E+02  2.3000E+02
                                      6.8900E-02  4.9160E+02  2.3030E+02
N2            1   300.000 15000.000   1.6630E-01  4.9160E+02  1.9200E+02
                                      1.4000E-02  4.9160E+02  3.0000E+02

Keywords: CHEMISTRY

Turbomachinery Data Files

The effects of turbomachinery in a duct may be simulated using an actuator duct model, originally developed at MIT. [Gong, Y., "A Computational Model for Rotating Stall and Inlet Distortion in Multistage Compressors," Ph. D. Dissertation, Dept. of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, Massachusetts, 1999.] The user input needed to define the characteristics of the turbomachinery being modeled is read from a set of turbomachinery data files. These are formatted files, with a separate file required for each blade row. Currently each blade row must be in a separate zone. The names of the files, and the zone each file corresponds to, is specified using the TURBOSPEC keyword block. Unless specified otherwise, all input data is non-dimensional.

The first three lines in the file are as follows:

   IROW
   RPM
   IBLADE

The format for the rest of the file depends on the value of the flag IBLADE.

IBLADE = 0

   NBLADE  NANG   NBODY
   RBLE    BLE    RBTE   BTE   (This line occurs NANG times.)
   ...
   RBODY   CKVIN  CKNIN        (This line occurs NBODY times.)
   ...

IBLADE = 2

For IBLADE = 2, only one line is needed after IBLADE:

   BODYF  RLXFM  RLXFE

IBLADE = 3

For IBLADE = 3, again only one line is needed after IBLADE:

   BODYF  RLXFE

Memory Log File (memdebug.lis)

A memory log file, always named memdebug.lis, may be created using DEBUG option 65 to track memory allocation/deallocation requests.

Keywords: DEBUG 65

Reserved Files

Unit numbers 15, 32, and 55 are reserved for proprietary features, and should not be used by Wind-US developers.