The property data of all liquid species must be defined in the LIQPROPERTIES ALL section of the surface mechanism file. The keyword ALL must be included on the LIQPROPERTIES line because Ansys Chemkin does not utilize an external data file to store additional liquid species data. The LIQPROPERTIES section must be provided before the REACTION section (and preferably after the THERM section if there is one).

The property data of each liquid species starts with its definition (symbol and atomic compositions) on the first line, which is followed by the properties. The properties of the liquid species can appear in any order; however, each property must be given over one single, unbroken line. The liquid species symbol is limited to 16 characters and is case-sensitive. The species symbol must be unique even for the same compound in different phases. For example, if H2O is used to represent the water vapor in the gas-phase mechanism, H2O cannot be used again for the liquid water; alternative choices would be H2O(L) or simply WATER. The elemental compositions of the species are provided after the species symbol on the same line. The elemental composition data are format-free and space delimited. Figure 2.5: Example of the liquid species property data in the Ansys Chemkin format shows an example of the liquid species property block in the surface mechanism file.

LIQPROPERTIES ALL
c2h5oh(l)       c  2  h  6 o  1             ! Ethanol
! From "The Properties of Gases and Liquids"
CriticalProperties=513.90 61.4 167.1        ! Tc(K) Pc(bar) Vc(cm3) *Required 
AcentricFac=0.644                           ! acentric factor *Required 
! From NIST webbook
RefLiqEnthalpy=2.76E5       ! Liquid enthalpy of formation at 298.15K (J/mol) *Optional 
RefLiqEntropy=159.86        ! Liquid entropy at 298.15K (J/mol-K) *Optional
! From DIPPR database
Density=(DIPPR105)1.6288 0.27469 0.23178                      !DIPPR EQ #105 *Required
SpecificHeat=(DIPPR100)102640 -139.63 -0.030341 0.0020386 0   !DIPPR EQ #100 *Required
HeatVaporization=(DIPPR106)55789000 0.31245 0 0 0             !DIPPR EQ #106 *Required
VaporPressure=(DIPPR101)73.304 -7122.3 -7.1424 0.0000028853 2 !DIPPR EQ #101 *Required
! liquid water
h2o(l)            h 2 o 1                    
CriticalProperties = 647.37 221.2 57.1       ! Tc(K) Pc(bar) Vc(cm3)
AcentricFac = 0.3852 
RefLiqEnthalpy = -2.8583E5  ! Liquid water enthalpy of formation at 298.15K (J/mol)
RefLiqEntropy = 69.95       ! Liquid water entropy at 298.15K (J/mol-K)
! From DIPPR database
Density = (DIPPR105) 3.557 0.2338 647.1 0.18721    
SpecificHeat = (DIPPR100) 2.7637e5 -2090.1 8.125 -0.014116 9.3701e-6    
HeatVaporization = (DIPPR106) 5.1546e7 0.28402 -0.15843 0.2375 0.0
VaporPressure = (DIPPR101) 73.649 -7258.2 -7.3037 4.1653e-6 2.0

Table 2.5: List of required properties for each liquid species lists the properties that must be provided for each liquid species. Detailed descriptions of the properties can be found in the corresponding sections in the Chemkin Theory Manual and the references therein. The liquid property keywords are case-insensitive.

The liquid properties are given as a function of temperature. Because the liquid state for most compounds of interest exists within a narrow temperature range, the liquid property data are usually fitted by one set of parameters. Ansys Chemkin will use the property method specified to calculate the property values for temperatures below the critical temperature.