Encyclopaedia Index

3 Physical Properties

contents

  1. Density
  2. Specific Heat Capacity
  3. Viscosity
  4. Thermal Conductivity
  5. Diffusivities
  6. Use With the PRPS Variable

3.1 Density

A call is made to the CHEMKIN routine CKRHOY to calculate the density.

This option is activated by setting

in the Q1 file, or, if the PRPS variable is used, by putting GRND9 into the PROPS data for RHO.

3.2 Specific Heat Capacity

In group 1 of GXCHKI, a call is made to calculate the species enthalpies at the reference temperature; the reference enthalpies are then stored for future use.
For the first species in the CHEMKIN system, a call is made to the CHEMKIN routine CKHMS to calculate the species enthalpies from which the effective specific heat capacities are calculated using the formula for given above.
The specific heats are stored away to be referenced on future entries to GXCHKI to obtain the specific heats for other species.

This option is activated by setting

in the Q1 file, or, if the PRPS variable is used, by putting GRND9 into the PROPS data for CP.

3.3 Viscosity

A call is made to the TRANLIB routine MCAVIS to calculate the mixture averaged dynamic viscosity from which the kinematic viscosity, required by PHOENICS, is calculated by division by density.

This option is activated by setting

in the Q1 file, or, if the PRPS variable is used, by putting GRND9 into the PROPS data for ENUL.

3.4 Thermal Conductivity

A call is made to the TRANLIB routine MCACON in order to calculate the mixture thermal conductivity.

This option is activated by setting

PRNDTL(TEM1)=-GRND9

in the Q1 file, or, if the PRPS variable is used, by putting -GRND9 into the PROPS data for thermal-conductivity.

3.5 Diffusivities

A call is made to the TRANLIB routine MCADIF when GXCHKI is entered for the first CHEMKIN species in order to calculate the mixture-averaged diffusivities for all species. The diffusivities are stored in F-array storage so that they may be retrieved in future calls to supply the diffusivities for the other species.

This option is activated by setting, for the variable numbered KSPEC,

in the Q1 file. (Activation through the PRPS variable is not possible.)

If the improved transport model is activated, then the diffusivity is divided by the mean molecular weight in order that the correct mean value is calculated for later use in group 8.

3.6 Use With the PRPS Variable

Some information has already been given on the use of the CHEMKIN properties with the PRPS variable, and now a summary will be given. If the PRPS variable is used then the user should insert into the Q1 file, or a PROPS file, a fragment of the form;

nGRND9GRND9GRND9GRND90.
0.0
0.0
0.0
0.0
where n can be any previously unused property number smaller than 100. In the Q1 file the full coding would be;

MATFLG=TNMAT=1
nGRND9GRND9GRND9GRND90.
0.0
0.0
0.0
0.0
where n has the same meaning as above.

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