CHEMISTRY
   FILE {filename [LOCAL]}
   {FROZEN | FINITE RATE}
   [FUEL AIR RATIO value]
   [LIU-VINOKUR]
   MASS [FRACTIONS] {AIR | sp1 sp2 ... spn}
   OMIT [THIRD-BODY] S1 S2 ... Sm ZONE range1[,range2[, ... rangen]]
   [VISCOSITY {SUTHERLAND | WILKE | KEYE | CONSTANT}]
ENDCHEMISTRY

This option allows the user to specify the real gas chemistry mode and input data for the desired species and reactions.

Note: The ARBITRARY INFLOW keyword block, if used, must come after the CHEMISTRY keyword block in the input data (.dat) file.

The various elements of the CHEMISTRY input block are defined as follows:

CHEMISTRY

Defines the beginning of the CHEMISTRY block

FILE {filename [LOCAL]}

Specifies the chemistry data file containing the thermodynamic data, finite rate coefficients, and transport property data for Wilkes' law. If the chemistry data file is located in the directory that WIND files (.cfl, .cgd, etc.) are running the keyword LOCAL must be specified.

{FROZEN | FINITE RATE}

	FROZEN		Selects frozen chemistry
	FINITE RATE		Selects finite rate chemistry

FUEL AIR RATIO value

value specifies the fuel-air ratio for H₂-air combustion (two-reaction global model).

LIU-VINOKUR

Selects the Liu and Vinokur equilibrium air curve fits. Valid to 50000 K, does not output species.

MASS [FRACTIONS] {AIR | sp1 sp2 ... spn}

Specifies the freestream (reference) mass fractions of the species. The keyword AIR indicates use of air mass fractions.

OMIT [THIRD-BODY] S1 S2 ... Sm ZONE range1[,range2[, ... rangen]]

This keyword allows control of the reacting species in a finite-rate chemistry solution on a zonal basis. Reactions leading to the production or destruction of the species given by S₁ through S_m will be eliminated in the selected zones. In addition, if the THIRD-BODY keyword parameter is used, any reaction involving the named species will be eliminated. The species will still be convected and diffused, maintaining conservation at zone boundaries.

Eliminating reactions in zones where they aren't relevant improves the overall efficiency of the calculation in two ways. First, the time required to perform the unnecessary computations is eliminated. And second, the stiffness of the system of equations is reduced, leading to faster convergence and greater stability.

In the zone specification, the range parameter(s) may be

	zonenum		Selects zone zonenum
	begzone:endzone		Selects all zones from begzone to endzone
	ALL		Selects all zones

Multiple OMIT keywords are allowed, with conflicting input resolved by using the latter of the conflicting entries.

VISCOSITY {SUTHERLAND | WILKE | KEYE | CONSTANT}

Selects the transport property equations. See the VISCOSITY keyword for details.

ENDCHEMISTRY

Defines the end of the CHEMISTRY block.

See Also: TEST 71

General and Standard Chemistry Packages

The chemistry data files supplied with the WIND code are summarized in the table below. [In the table, the symbol e^- is electron density, and NO⁺ is ionized nitrogen oxide. Also, T_max is the maximum temperature at which the curve fits are valid, Nc is the number of thermodynamic curve fit segments, Nr is the number of reaction equations, and 3d denotes Variable or Average 3rd-body efficiency.}

General and Standard Chemistry Packages

Species	File(s)	Tmax	Nc	Nr	3d
O2, NO, O, N, N2	air-5sp-std-06k.chm air-5sp-gen-06k.chm	6000 K	1	5	V
O2, NO, O, N, N2	air-5sp-std-15k.chm air-5sp-gen-15k.chm	15000 K	3	5	V
O2, NO, O, N, N2	air-5sp-std-30k.chm air-5sp-gen-30k.chm	30000 K	5	5	V
O2, NO, O, N, NO+, e-, N2	air-7sp-std-06k.chm	6000 K	1	6	V
O2, NO, O, N, NO+, e-, N2	air-7sp-std-15k.chm air-7sp-gen-15k.chm	15000 K	3	6	V
O2, NO, O, N, NO+, e-, N2	air-7sp-std-30k.chm air-7sp-gen-30k.chm	30000 K	5	6	V
O2, OH, H2, H2O, N2	h2air-5sp-std-06k.chm	6000 K	1	2
O2, OH, H2, H2O, N2	h2air-5sp-std-15k.chm	15000 K	3	2
O2, H, H2, H2O, N2	Not yet available
O2, H, H2, H2O, OH, O, N2	h2air-7sp-std-15k.chm h2air-7sp-gen-15k.chm h2air-7sp-bak-15k.chm	15000 K	3	8
O2, CO2, H2O, NO2, N2	Not yet available