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Old   February 1, 2016, 08:44
Default Ansys CFX problem: unexpected very high temperatures in premix laminar combustion
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Faizan
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Hello everybody,

I am new to the field of combustion CFD. I have used Ansys CFX before but only for non-reacting flows. I am trying to simulate a premix laminar combustion model using Ansys CFX. The model is a simple tube, which I am analyzing as a 2D symmetric part. Inlet velocity is 1 m/s. Inlet Temperature is 298 K. Outlet condition is 1 atm. Mass fractions for methane and oxygen at the inlet are 0.2 and 0.8 respectively. I am using a temperature condition at the walls such that for first few iterations a 2200 K temperature is applied there and then it is switched to 298 K. Also I am using no turbulence model (Laminar) and thermal energy model. For chemistry, I am using Finite rate chemistry (one step).

The problem I am having is that after the solution converges, temperatures in the domain are very unexpectedly high. Maximum temperature is 6138 K. This is wrong as Adiabatic flame temperature for methane combustion is around 2200 K. Can you please help me in this matter? I have attached the image of high temperature contour. and below is the ccl file :
Attached Images
File Type: jpg high temp.jpg (84.5 KB, 30 views)
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Old   February 1, 2016, 08:46
Default .CCL file part 1
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Faizan
Join Date: Feb 2016
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# State file created: 2016/02/01 13:40:57
# Build 16.2 2015.06.30-00.06-134402

LIBRARY:
CEL:
EXPRESSIONS:
temp cond = if(aitern<50,2200[K],298[K])
END
END
MATERIAL GROUP: Air Data
Group Description = Ideal gas and constant property air. Constant \
properties are for dry air at STP (0 C, 1 atm) and 25 C, 1 atm.
END
MATERIAL GROUP: CHT Solids
Group Description = Pure solid substances that can be used for conjugate \
heat transfer.
END
MATERIAL GROUP: Calorically Perfect Ideal Gases
Group Description = Ideal gases with constant specific heat capacity. \
Specific heat is evaluated at STP.
END
MATERIAL GROUP: Constant Property Gases
Group Description = Gaseous substances with constant properties. \
Properties are calculated at STP (0C and 1 atm). Can be combined with \
NASA SP-273 materials for combustion modelling.
END
MATERIAL GROUP: Constant Property Liquids
Group Description = Liquid substances with constant properties.
END
MATERIAL GROUP: Dry Peng Robinson
Group Description = Materials with properties specified using the built \
in Peng Robinson equation of state. Suitable for dry real gas modelling.
END
MATERIAL GROUP: Dry Redlich Kwong
Group Description = Materials with properties specified using the built \
in Redlich Kwong equation of state. Suitable for dry real gas modelling.
END
MATERIAL GROUP: Dry Soave Redlich Kwong
Group Description = Materials with properties specified using the built \
in Soave Redlich Kwong equation of state. Suitable for dry real gas \
modelling.
END
MATERIAL GROUP: Dry Steam
Group Description = Materials with properties specified using the IAPWS \
equation of state. Suitable for dry steam modelling.
END
MATERIAL GROUP: Gas Phase Combustion
Group Description = Ideal gas materials which can be use for gas phase \
combustion. Ideal gas specific heat coefficients are specified using \
the NASA SP-273 format.
END
MATERIAL GROUP: IAPWS IF97
Group Description = Liquid, vapour and binary mixture materials which use \
the IAPWS IF-97 equation of state. Materials are suitable for \
compressible liquids, phase change calculations and dry steam flows.
END
MATERIAL GROUP: Interphase Mass Transfer
Group Description = Materials with reference properties suitable for \
performing either Eulerian or Lagrangian multiphase mass transfer \
problems. Examples include cavitation, evaporation or condensation.
END
MATERIAL GROUP: Liquid Phase Combustion
Group Description = Liquid and homogenous binary mixture materials which \
can be included with Gas Phase Combustion materials if combustion \
modelling also requires phase change (eg: evaporation) for certain \
components.
END
MATERIAL GROUP: Particle Solids
Group Description = Pure solid substances that can be used for particle \
tracking
END
MATERIAL GROUP: Peng Robinson Dry Hydrocarbons
Group Description = Common hydrocarbons which use the Peng Robinson \
equation of state. Suitable for dry real gas models.
END
MATERIAL GROUP: Peng Robinson Dry Refrigerants
Group Description = Common refrigerants which use the Peng Robinson \
equation of state. Suitable for dry real gas models.
END
MATERIAL GROUP: Peng Robinson Dry Steam
Group Description = Water materials which use the Peng Robinson equation \
of state. Suitable for dry steam modelling.
END
MATERIAL GROUP: Peng Robinson Wet Hydrocarbons
Group Description = Common hydrocarbons which use the Peng Robinson \
equation of state. Suitable for condensing real gas models.
END
MATERIAL GROUP: Peng Robinson Wet Refrigerants
Group Description = Common refrigerants which use the Peng Robinson \
equation of state. Suitable for condensing real gas models.
END
MATERIAL GROUP: Peng Robinson Wet Steam
Group Description = Water materials which use the Peng Robinson equation \
of state. Suitable for condensing steam modelling.
END
MATERIAL GROUP: Real Gas Combustion
Group Description = Real gas materials which can be use for gas phase \
combustion. Ideal gas specific heat coefficients are specified using \
the NASA SP-273 format.
END
MATERIAL GROUP: Redlich Kwong Dry Hydrocarbons
Group Description = Common hydrocarbons which use the Redlich Kwong \
equation of state. Suitable for dry real gas models.
END
MATERIAL GROUP: Redlich Kwong Dry Refrigerants
Group Description = Common refrigerants which use the Redlich Kwong \
equation of state. Suitable for dry real gas models.
END
MATERIAL GROUP: Redlich Kwong Dry Steam
Group Description = Water materials which use the Redlich Kwong equation \
of state. Suitable for dry steam modelling.
END
MATERIAL GROUP: Redlich Kwong Wet Hydrocarbons
Group Description = Common hydrocarbons which use the Redlich Kwong \
equation of state. Suitable for condensing real gas models.
END
MATERIAL GROUP: Redlich Kwong Wet Refrigerants
Group Description = Common refrigerants which use the Redlich Kwong \
equation of state. Suitable for condensing real gas models.
END
MATERIAL GROUP: Redlich Kwong Wet Steam
Group Description = Water materials which use the Redlich Kwong equation \
of state. Suitable for condensing steam modelling.
END
MATERIAL GROUP: Soave Redlich Kwong Dry Hydrocarbons
Group Description = Common hydrocarbons which use the Soave Redlich Kwong \
equation of state. Suitable for dry real gas models.
END
MATERIAL GROUP: Soave Redlich Kwong Dry Refrigerants
Group Description = Common refrigerants which use the Soave Redlich Kwong \
equation of state. Suitable for dry real gas models.
END
MATERIAL GROUP: Soave Redlich Kwong Dry Steam
Group Description = Water materials which use the Soave Redlich Kwong \
equation of state. Suitable for dry steam modelling.
END
MATERIAL GROUP: Soave Redlich Kwong Wet Hydrocarbons
Group Description = Common hydrocarbons which use the Soave Redlich Kwong \
equation of state. Suitable for condensing real gas models.
END
MATERIAL GROUP: Soave Redlich Kwong Wet Refrigerants
Group Description = Common refrigerants which use the Soave Redlich Kwong \
equation of state. Suitable for condensing real gas models.
END
MATERIAL GROUP: Soave Redlich Kwong Wet Steam
Group Description = Water materials which use the Soave Redlich Kwong \
equation of state. Suitable for condensing steam modelling.
END
MATERIAL GROUP: Soot
Group Description = Solid substances that can be used when performing \
soot modelling
END
MATERIAL GROUP: User
Group Description = Materials that are defined by the user
END
MATERIAL GROUP: Water Data
Group Description = Liquid and vapour water materials with constant \
properties. Can be combined with NASA SP-273 materials for combustion \
modelling.
END
MATERIAL GROUP: Wet Peng Robinson
Group Description = Materials with properties specified using the built \
in Peng Robinson equation of state. Suitable for wet real gas modelling.
END
MATERIAL GROUP: Wet Redlich Kwong
Group Description = Materials with properties specified using the built \
in Redlich Kwong equation of state. Suitable for wet real gas modelling.
END
MATERIAL GROUP: Wet Soave Redlich Kwong
Group Description = Materials with properties specified using the built \
in Soave Redlich Kwong equation of state. Suitable for wet real gas \
modelling.
END
MATERIAL GROUP: Wet Steam
Group Description = Materials with properties specified using the IAPWS \
equation of state. Suitable for wet steam modelling.
END
MATERIAL: Air Ideal Gas
Material Description = Air Ideal Gas (constant Cp)
Material Group = Air Data, Calorically Perfect Ideal Gases
Option = Pure Substance
Thermodynamic State = Gas
PROPERTIES:
Option = General Material
EQUATION OF STATE:
Molar Mass = 28.96 [kg kmol^-1]
Option = Ideal Gas
END
SPECIFIC HEAT CAPACITY:
Option = Value
Specific Heat Capacity = 1.0044E+03 [J kg^-1 K^-1]
Specific Heat Type = Constant Pressure
END
REFERENCE STATE:
Option = Specified Point
Reference Pressure = 1 [atm]
Reference Specific Enthalpy = 0. [J/kg]
Reference Specific Entropy = 0. [J/kg/K]
Reference Temperature = 25 [C]
END
DYNAMIC VISCOSITY:
Dynamic Viscosity = 1.831E-05 [kg m^-1 s^-1]
Option = Value
END
THERMAL CONDUCTIVITY:
Option = Value
Thermal Conductivity = 2.61E-2 [W m^-1 K^-1]
END
ABSORPTION COEFFICIENT:
Absorption Coefficient = 0.01 [m^-1]
Option = Value
END
SCATTERING COEFFICIENT:
Option = Value
Scattering Coefficient = 0.0 [m^-1]
END
REFRACTIVE INDEX:
Option = Value
Refractive Index = 1.0 [m m^-1]
END
END
END
MATERIAL: Air at 25 C
Material Description = Air at 25 C and 1 atm (dry)
Material Group = Air Data, Constant Property Gases
Option = Pure Substance
Thermodynamic State = Gas
PROPERTIES:
Option = General Material
EQUATION OF STATE:
Density = 1.185 [kg m^-3]
Molar Mass = 28.96 [kg kmol^-1]
Option = Value
END
SPECIFIC HEAT CAPACITY:
Option = Value
Specific Heat Capacity = 1.0044E+03 [J kg^-1 K^-1]
Specific Heat Type = Constant Pressure
END
REFERENCE STATE:
Option = Specified Point
Reference Pressure = 1 [atm]
Reference Specific Enthalpy = 0. [J/kg]
Reference Specific Entropy = 0. [J/kg/K]
Reference Temperature = 25 [C]
END
DYNAMIC VISCOSITY:
Dynamic Viscosity = 1.831E-05 [kg m^-1 s^-1]
Option = Value
END
THERMAL CONDUCTIVITY:
Option = Value
Thermal Conductivity = 2.61E-02 [W m^-1 K^-1]
END
ABSORPTION COEFFICIENT:
Absorption Coefficient = 0.01 [m^-1]
Option = Value
END
SCATTERING COEFFICIENT:
Option = Value
Scattering Coefficient = 0.0 [m^-1]
END
REFRACTIVE INDEX:
Option = Value
Refractive Index = 1.0 [m m^-1]
END
THERMAL EXPANSIVITY:
Option = Value
Thermal Expansivity = 0.003356 [K^-1]
END
END
END
MATERIAL: Aluminium
Material Group = CHT Solids, Particle Solids
Option = Pure Substance
Thermodynamic State = Solid
PROPERTIES:
Option = General Material
EQUATION OF STATE:
Density = 2702 [kg m^-3]
Molar Mass = 26.98 [kg kmol^-1]
Option = Value
END
SPECIFIC HEAT CAPACITY:
Option = Value
Specific Heat Capacity = 9.03E+02 [J kg^-1 K^-1]
END
REFERENCE STATE:
Option = Specified Point
Reference Specific Enthalpy = 0 [J/kg]
Reference Specific Entropy = 0 [J/kg/K]
Reference Temperature = 25 [C]
END
THERMAL CONDUCTIVITY:
Option = Value
Thermal Conductivity = 237 [W m^-1 K^-1]
END
END
END
MATERIAL: CH4
Material Description = Methane CH4
Material Group = Gas Phase Combustion
Option = Pure Substance
Thermodynamic State = Gas
PROPERTIES:
Option = General Material
EQUATION OF STATE:
Molar Mass = 16.04 [kg kmol^-1]
Option = Ideal Gas
END
SPECIFIC HEAT CAPACITY:
Option = NASA Format
LOWER INTERVAL COEFFICIENTS:
NASA a1 = 0.07787415E+01 []
NASA a2 = 0.01747668E+00 [K^-1]
NASA a3 = -0.02783409E-03 [K^-2]
NASA a4 = 0.03049708E-06 [K^-3]
NASA a5 = -0.01223931E-09 [K^-4]
NASA a6 = -0.09825229E+05 [K]
NASA a7 = 0.01372219E+03 []
END
TEMPERATURE LIMITS:
Lower Temperature = 300 [K]
Midpoint Temperature = 1000 [K]
Upper Temperature = 5000 [K]
END
UPPER INTERVAL COEFFICIENTS:
NASA a1 = 0.01683479E+02 []
NASA a2 = 0.01023724E+00 [K^-1]
NASA a3 = -0.03875129E-04 [K^-2]
NASA a4 = 0.06785585E-08 [K^-3]
NASA a5 = -0.04503423E-12 [K^-4]
NASA a6 = -0.01008079E+06 [K]
NASA a7 = 0.09623395E+02 []
END
END
REFERENCE STATE:
Option = NASA Format
Reference Pressure = 1 [atm]
Reference Temperature = 25 [C]
END
DYNAMIC VISCOSITY:
Dynamic Viscosity = 11.1E-06 [kg m^-1 s^-1]
Option = Value
END
THERMAL CONDUCTIVITY:
Option = Value
Thermal Conductivity = 343E-04 [W m^-1 K^-1]
END
ABSORPTION COEFFICIENT:
Absorption Coefficient = 1.0 [m^-1]
Option = Value
END
SCATTERING COEFFICIENT:
Option = Value
Scattering Coefficient = 0.0 [m^-1]
END
REFRACTIVE INDEX:
Option = Value
Refractive Index = 1.0 [m m^-1]
END
END
END
MATERIAL: CO
Material Description = Carbon Monoxide CO
Material Group = Gas Phase Combustion
Option = Pure Substance
Thermodynamic State = Gas
PROPERTIES:
Option = General Material
EQUATION OF STATE:
Molar Mass = 28.01 [kg kmol^-1]
Option = Ideal Gas
END
SPECIFIC HEAT CAPACITY:
Option = NASA Format
LOWER INTERVAL COEFFICIENTS:
NASA a1 = 0.03262452E+02 []
NASA a2 = 0.01511941E-01 [K^-1]
NASA a3 = -0.03881755E-04 [K^-2]
NASA a4 = 0.05581944E-07 [K^-3]
NASA a5 = -0.02474951E-10 [K^-4]
NASA a6 = -0.01431054E+06 [K]
NASA a7 = 0.04848897E+02 []
END
TEMPERATURE LIMITS:
Lower Temperature = 300 [K]
Midpoint Temperature = 1000 [K]
Upper Temperature = 5000 [K]
END
UPPER INTERVAL COEFFICIENTS:
NASA a1 = 0.03025078E+02 []
NASA a2 = 0.01442689E-01 [K^-1]
NASA a3 = -0.05630828E-05 [K^-2]
NASA a4 = 0.01018581E-08 [K^-3]
NASA a5 = -0.06910952E-13 [K^-4]
NASA a6 = -0.01426835E+06 [K]
NASA a7 = 0.06108218E+02 []
END
END
REFERENCE STATE:
Option = NASA Format
Reference Pressure = 1 [atm]
Reference Temperature = 25 [C]
END
DYNAMIC VISCOSITY:
Dynamic Viscosity = 16.6E-06 [kg m^-1 s^-1]
Option = Value
END
THERMAL CONDUCTIVITY:
Option = Value
Thermal Conductivity = 251E-04 [W m^-1 K^-1]
END
ABSORPTION COEFFICIENT:
Absorption Coefficient = 1.0 [m^-1]
Option = Value
END
SCATTERING COEFFICIENT:
Option = Value
Scattering Coefficient = 0.0 [m^-1]
END
REFRACTIVE INDEX:
Option = Value
Refractive Index = 1.0 [m m^-1]
END
END
END
MATERIAL: CO2
Material Description = Carbon Dioxide CO2
Material Group = Gas Phase Combustion
Option = Pure Substance
Thermodynamic State = Gas
PROPERTIES:
Option = General Material
EQUATION OF STATE:
Molar Mass = 44.01 [kg kmol^-1]
Option = Ideal Gas
END
SPECIFIC HEAT CAPACITY:
Option = NASA Format
LOWER INTERVAL COEFFICIENTS:
NASA a1 = 0.02275725E+02 []
NASA a2 = 0.09922072E-01 [K^-1]
NASA a3 = -0.01040911E-03 [K^-2]
NASA a4 = 0.06866687E-07 [K^-3]
NASA a5 = -0.02117280E-10 [K^-4]
NASA a6 = -0.04837314E+06 [K]
NASA a7 = 0.01018849E+03 []
END
TEMPERATURE LIMITS:
Lower Temperature = 300 [K]
Midpoint Temperature = 1000 [K]
Upper Temperature = 5000 [K]
END
UPPER INTERVAL COEFFICIENTS:
NASA a1 = 0.04453623E+02 []
NASA a2 = 0.03140169E-01 [K^-1]
NASA a3 = -0.01278411E-04 [K^-2]
NASA a4 = 0.02393997E-08 [K^-3]
NASA a5 = -0.01669033E-12 [K^-4]
NASA a6 = -0.04896696E+06 [K]
NASA a7 = -0.09553959E+01 []
END
END
REFERENCE STATE:
Option = NASA Format
Reference Pressure = 1 [atm]
Reference Temperature = 25 [C]
END
DYNAMIC VISCOSITY:
Dynamic Viscosity = 14.9E-06 [kg m^-1 s^-1]
Option = Value
END
THERMAL CONDUCTIVITY:
Option = Value
Thermal Conductivity = 145E-04 [W m^-1 K^-1]
END
ABSORPTION COEFFICIENT:
Absorption Coefficient = 1.0 [m^-1]
Option = Value
END
SCATTERING COEFFICIENT:
Option = Value
Scattering Coefficient = 0.0 [m^-1]
END
REFRACTIVE INDEX:
Option = Value
Refractive Index = 1.0 [m m^-1]
END
END
END
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Old   February 1, 2016, 08:47
Default .ccl part 2
  #3
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Faizan
Join Date: Feb 2016
Posts: 4
Rep Power: 6
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MATERIAL: Copper
Material Group = CHT Solids, Particle Solids
Option = Pure Substance
Thermodynamic State = Solid
PROPERTIES:
Option = General Material
EQUATION OF STATE:
Density = 8933 [kg m^-3]
Molar Mass = 63.55 [kg kmol^-1]
Option = Value
END
SPECIFIC HEAT CAPACITY:
Option = Value
Specific Heat Capacity = 3.85E+02 [J kg^-1 K^-1]
END
REFERENCE STATE:
Option = Specified Point
Reference Specific Enthalpy = 0 [J/kg]
Reference Specific Entropy = 0 [J/kg/K]
Reference Temperature = 25 [C]
END
THERMAL CONDUCTIVITY:
Option = Value
Thermal Conductivity = 401.0 [W m^-1 K^-1]
END
END
END
MATERIAL: H2
Material Description = Hydrogen H2
Material Group = Gas Phase Combustion
Option = Pure Substance
Thermodynamic State = Gas
PROPERTIES:
Option = General Material
EQUATION OF STATE:
Molar Mass = 2.016 [kg kmol^-1]
Option = Ideal Gas
END
SPECIFIC HEAT CAPACITY:
Option = NASA Format
LOWER INTERVAL COEFFICIENTS:
NASA a1 = 0.03298124E+02 []
NASA a2 = 0.08249442E-02 [K^-1]
NASA a3 = -0.08143015E-05 [K^-2]
NASA a4 = -0.09475434E-09 [K^-3]
NASA a5 = 0.04134872E-11 [K^-4]
NASA a6 = -0.01012521E+05 [K]
NASA a7 = -0.03294094E+02 []
END
TEMPERATURE LIMITS:
Lower Temperature = 300 [K]
Midpoint Temperature = 1000 [K]
Upper Temperature = 5000 [K]
END
UPPER INTERVAL COEFFICIENTS:
NASA a1 = 0.02991423E+02 []
NASA a2 = 0.07000644E-02 [K^-1]
NASA a3 = -0.05633829E-06 [K^-2]
NASA a4 = -0.09231578E-10 [K^-3]
NASA a5 = 0.01582752E-13 [K^-4]
NASA a6 = -0.08350340E+04 [K]
NASA a7 = -0.01355110E+02 []
END
END
REFERENCE STATE:
Option = NASA Format
Reference Pressure = 1 [atm]
Reference Temperature = 25 [C]
END
DYNAMIC VISCOSITY:
Dynamic Viscosity = 8.8E-06 [kg m^-1 s^-1]
Option = Value
END
THERMAL CONDUCTIVITY:
Option = Value
Thermal Conductivity = 1.809E-01 [W m^-1 K^-1]
END
ABSORPTION COEFFICIENT:
Absorption Coefficient = 1.0 [m^-1]
Option = Value
END
SCATTERING COEFFICIENT:
Option = Value
Scattering Coefficient = 0.0 [m^-1]
END
REFRACTIVE INDEX:
Option = Value
Refractive Index = 1.0 [m m^-1]
END
END
END
MATERIAL: H2O
Material Description = Water Vapour
Material Group = Gas Phase Combustion, Interphase Mass Transfer, Water Data
Option = Pure Substance
Thermodynamic State = Gas
PROPERTIES:
Option = General Material
EQUATION OF STATE:
Molar Mass = 18.02 [kg kmol^-1]
Option = Ideal Gas
END
SPECIFIC HEAT CAPACITY:
Option = NASA Format
LOWER INTERVAL COEFFICIENTS:
NASA a1 = 0.03386842E+02 []
NASA a2 = 0.03474982E-01 [K^-1]
NASA a3 = -0.06354696E-04 [K^-2]
NASA a4 = 0.06968581E-07 [K^-3]
NASA a5 = -0.02506588E-10 [K^-4]
NASA a6 = -0.03020811E+06 [K]
NASA a7 = 0.02590233E+02 []
END
TEMPERATURE LIMITS:
Lower Temperature = 300 [K]
Midpoint Temperature = 1000 [K]
Upper Temperature = 5000 [K]
END
UPPER INTERVAL COEFFICIENTS:
NASA a1 = 0.02672146E+02 []
NASA a2 = 0.03056293E-01 [K^-1]
NASA a3 = -0.08730260E-05 [K^-2]
NASA a4 = 0.01200996E-08 [K^-3]
NASA a5 = -0.06391618E-13 [K^-4]
NASA a6 = -0.02989921E+06 [K]
NASA a7 = 0.06862817E+02 []
END
END
REFERENCE STATE:
Option = NASA Format
Reference Pressure = 1 [atm]
Reference Temperature = 25 [C]
END
DYNAMIC VISCOSITY:
Dynamic Viscosity = 9.4E-06 [kg m^-1 s^-1]
Option = Value
END
THERMAL CONDUCTIVITY:
Option = Value
Thermal Conductivity = 193E-04 [W m^-1 K^-1]
END
ABSORPTION COEFFICIENT:
Absorption Coefficient = 1.0 [m^-1]
Option = Value
END
SCATTERING COEFFICIENT:
Option = Value
Scattering Coefficient = 0.0 [m^-1]
END
REFRACTIVE INDEX:
Option = Value
Refractive Index = 1.0 [m m^-1]
END
END
END
MATERIAL: N2
Material Description = Nitrogen N2
Material Group = Gas Phase Combustion
Option = Pure Substance
Thermodynamic State = Gas
PROPERTIES:
Option = General Material
EQUATION OF STATE:
Molar Mass = 28.01 [kg kmol^-1]
Option = Ideal Gas
END
SPECIFIC HEAT CAPACITY:
Option = NASA Format
LOWER INTERVAL COEFFICIENTS:
NASA a1 = 0.03298677E+02 []
NASA a2 = 0.01408240E-01 [K^-1]
NASA a3 = -0.03963222E-04 [K^-2]
NASA a4 = 0.05641515E-07 [K^-3]
NASA a5 = -0.02444855E-10 [K^-4]
NASA a6 = -0.01020900E+05 [K]
NASA a7 = 0.03950372E+02 []
END
TEMPERATURE LIMITS:
Lower Temperature = 300 [K]
Midpoint Temperature = 1000 [K]
Upper Temperature = 5000 [K]
END
UPPER INTERVAL COEFFICIENTS:
NASA a1 = 0.02926640E+02 []
NASA a2 = 0.01487977E-01 [K^-1]
NASA a3 = -0.05684761E-05 [K^-2]
NASA a4 = 0.01009704E-08 [K^-3]
NASA a5 = -0.06753351E-13 [K^-4]
NASA a6 = -0.09227977E+04 [K]
NASA a7 = 0.05980528E+02 []
END
END
REFERENCE STATE:
Option = NASA Format
Reference Pressure = 1 [atm]
Reference Temperature = 25 [C]
END
DYNAMIC VISCOSITY:
Dynamic Viscosity = 17.7E-06 [kg m^-1 s^-1]
Option = Value
END
THERMAL CONDUCTIVITY:
Option = Value
Thermal Conductivity = 259E-04 [W m^-1 K^-1]
END
ABSORPTION COEFFICIENT:
Absorption Coefficient = 1.0 [m^-1]
Option = Value
END
SCATTERING COEFFICIENT:
Option = Value
Scattering Coefficient = 0.0 [m^-1]
END
REFRACTIVE INDEX:
Option = Value
Refractive Index = 1.0 [m m^-1]
END
END
END
MATERIAL: O2
Material Description = Oxygen O2
Material Group = Gas Phase Combustion
Option = Pure Substance
Thermodynamic State = Gas
PROPERTIES:
Option = General Material
EQUATION OF STATE:
Molar Mass = 31.99 [kg kmol^-1]
Option = Ideal Gas
END
SPECIFIC HEAT CAPACITY:
Option = NASA Format
LOWER INTERVAL COEFFICIENTS:
NASA a1 = 0.03212936E+02 []
NASA a2 = 0.01127486E-01 [K^-1]
NASA a3 = -0.05756150E-05 [K^-2]
NASA a4 = 0.01313877E-07 [K^-3]
NASA a5 = -0.08768554E-11 [K^-4]
NASA a6 = -0.01005249E+05 [K]
NASA a7 = 0.06034738E+02 []
END
TEMPERATURE LIMITS:
Lower Temperature = 300 [K]
Midpoint Temperature = 1000 [K]
Upper Temperature = 5000 [K]
END
UPPER INTERVAL COEFFICIENTS:
NASA a1 = 0.03697578E+02 []
NASA a2 = 0.06135197E-02 [K^-1]
NASA a3 = -0.01258842E-05 [K^-2]
NASA a4 = 0.01775281E-09 [K^-3]
NASA a5 = -0.01136435E-13 [K^-4]
NASA a6 = -0.01233930E+05 [K]
NASA a7 = 0.03189166E+02 []
END
END
REFERENCE STATE:
Option = NASA Format
Reference Pressure = 1 [atm]
Reference Temperature = 25 [C]
END
DYNAMIC VISCOSITY:
Dynamic Viscosity = 19.2E-06 [kg m^-1 s^-1]
Option = Value
END
THERMAL CONDUCTIVITY:
Option = Value
Thermal Conductivity = 266E-04 [W m^-1 K^-1]
END
ABSORPTION COEFFICIENT:
Absorption Coefficient = 1.0 [m^-1]
Option = Value
END
SCATTERING COEFFICIENT:
Option = Value
Scattering Coefficient = 0.0 [m^-1]
END
REFRACTIVE INDEX:
Option = Value
Refractive Index = 1.0 [m m^-1]
END
END
END
MATERIAL: Soot
Material Group = Soot
Option = Pure Substance
Thermodynamic State = Solid
PROPERTIES:
Option = General Material
EQUATION OF STATE:
Density = 2000 [kg m^-3]
Molar Mass = 12 [kg kmol^-1]
Option = Value
END
REFERENCE STATE:
Option = Automatic
END
ABSORPTION COEFFICIENT:
Absorption Coefficient = 0 [m^-1]
Option = Value
END
END
END
MATERIAL: Steel
Material Group = CHT Solids, Particle Solids
Option = Pure Substance
Thermodynamic State = Solid
PROPERTIES:
Option = General Material
EQUATION OF STATE:
Density = 7854 [kg m^-3]
Molar Mass = 55.85 [kg kmol^-1]
Option = Value
END
SPECIFIC HEAT CAPACITY:
Option = Value
Specific Heat Capacity = 4.34E+02 [J kg^-1 K^-1]
END
REFERENCE STATE:
Option = Specified Point
Reference Specific Enthalpy = 0 [J/kg]
Reference Specific Entropy = 0 [J/kg/K]
Reference Temperature = 25 [C]
END
THERMAL CONDUCTIVITY:
Option = Value
Thermal Conductivity = 60.5 [W m^-1 K^-1]
END
END
END
MATERIAL: Water
Material Description = Water (liquid)
Material Group = Water Data, Constant Property Liquids
Option = Pure Substance
Thermodynamic State = Liquid
PROPERTIES:
Option = General Material
EQUATION OF STATE:
Density = 997.0 [kg m^-3]
Molar Mass = 18.02 [kg kmol^-1]
Option = Value
END
SPECIFIC HEAT CAPACITY:
Option = Value
Specific Heat Capacity = 4181.7 [J kg^-1 K^-1]
Specific Heat Type = Constant Pressure
END
REFERENCE STATE:
Option = Specified Point
Reference Pressure = 1 [atm]
Reference Specific Enthalpy = 0.0 [J/kg]
Reference Specific Entropy = 0.0 [J/kg/K]
Reference Temperature = 25 [C]
END
DYNAMIC VISCOSITY:
Dynamic Viscosity = 8.899E-4 [kg m^-1 s^-1]
Option = Value
END
THERMAL CONDUCTIVITY:
Option = Value
Thermal Conductivity = 0.6069 [W m^-1 K^-1]
END
ABSORPTION COEFFICIENT:
Absorption Coefficient = 1.0 [m^-1]
Option = Value
END
SCATTERING COEFFICIENT:
Option = Value
Scattering Coefficient = 0.0 [m^-1]
END
REFRACTIVE INDEX:
Option = Value
Refractive Index = 1.0 [m m^-1]
END
THERMAL EXPANSIVITY:
Option = Value
Thermal Expansivity = 2.57E-04 [K^-1]
END
END
END
MATERIAL: Water Ideal Gas
Material Description = Water Vapour Ideal Gas (100 C and 1 atm)
Material Group = Calorically Perfect Ideal Gases, Water Data
Option = Pure Substance
Thermodynamic State = Gas
PROPERTIES:
Option = General Material
EQUATION OF STATE:
Molar Mass = 18.02 [kg kmol^-1]
Option = Ideal Gas
END
SPECIFIC HEAT CAPACITY:
Option = Value
Specific Heat Capacity = 2080.1 [J kg^-1 K^-1]
Specific Heat Type = Constant Pressure
END
REFERENCE STATE:
Option = Specified Point
Reference Pressure = 1.014 [bar]
Reference Specific Enthalpy = 0. [J/kg]
Reference Specific Entropy = 0. [J/kg/K]
Reference Temperature = 100 [C]
END
DYNAMIC VISCOSITY:
Dynamic Viscosity = 9.4E-06 [kg m^-1 s^-1]
Option = Value
END
THERMAL CONDUCTIVITY:
Option = Value
Thermal Conductivity = 193E-04 [W m^-1 K^-1]
END
ABSORPTION COEFFICIENT:
Absorption Coefficient = 1.0 [m^-1]
Option = Value
END
SCATTERING COEFFICIENT:
Option = Value
Scattering Coefficient = 0.0 [m^-1]
END
REFRACTIVE INDEX:
Option = Value
Refractive Index = 1.0 [m m^-1]
END
END
END
REACTION: Methane Air WD1
Additional Materials List = CH4,O2,CO2,H2O
Option = Multi Step
Reaction Description = Methane Air Single Step
Reactions List = Methane Oxygen WD1
END
REACTION: Methane Oxygen WD1
Option = Single Step
FORWARD REACTION RATE:
Option = Arrhenius
Pre Exponential Factor = 8.3E6 [s^-1]
Temperature Exponent = 0.
REACTION ACTIVATION:
Activation Energy = 30. [kcal mol^-1]
Option = Activation Energy
END
END
PRODUCTS:
Materials List = CO2,H2O
Option = Child Materials
CHILD MATERIAL: CO2
Option = Stoichiometric
Stoichiometric Coefficient = 1.0
END
CHILD MATERIAL: H2O
Option = Stoichiometric
Stoichiometric Coefficient = 2.0
END
END
REACTANTS:
Materials List = CH4,O2
Option = Child Materials
CHILD MATERIAL: CH4
Option = Stoichiometric
Reaction Order = -0.3
Stoichiometric Coefficient = 1.0
END
CHILD MATERIAL: O2
Option = Stoichiometric
Reaction Order = 1.3
Stoichiometric Coefficient = 2.0
END
END
END
END
FLOW: Flow Analysis 1
SOLUTION UNITS:
Angle Units = [rad]
Length Units = [m]
Mass Units = [kg]
Solid Angle Units = [sr]
Temperature Units = [K]
Time Units = [s]
END
ANALYSIS TYPE:
Option = Steady State
EXTERNAL SOLVER COUPLING:
Option = None
END
END
DOMAIN: Default Domain
Coord Frame = Coord 0
Domain Type = Fluid
Location = B16
BOUNDARY: Boundary 1
Boundary Type = SYMMETRY
Location = F17.16,F18.16
END
BOUNDARY: inlet
Boundary Type = INLET
Location = F22.16
BOUNDARY CONDITIONS:
COMPONENT: CH4
Mass Fraction = 0.2
Option = Mass Fraction
END
COMPONENT: CO2
Mass Fraction = 0.0
Option = Mass Fraction
END
COMPONENT: O2
Mass Fraction = 0.8
Option = Mass Fraction
END
FLOW REGIME:
Option = Subsonic
END
HEAT TRANSFER:
Option = Static Temperature
Static Temperature = 298 [K]
END
MASS AND MOMENTUM:
Normal Speed = 1 [m s^-1]
Option = Normal Speed
END
END
END
BOUNDARY: outlet
Boundary Type = OUTLET
Location = F20.16
BOUNDARY CONDITIONS:
FLOW REGIME:
Option = Subsonic
END
MASS AND MOMENTUM:
Option = Static Pressure
Relative Pressure = 1 [atm]
END
END
END
BOUNDARY: top wall
Boundary Type = WALL
Location = F19.16,F21.16
BOUNDARY CONDITIONS:
HEAT TRANSFER:
Fixed Temperature = temp cond
Option = Fixed Temperature
END
MASS AND MOMENTUM:
Option = No Slip Wall
END
END
END
DOMAIN MODELS:
BUOYANCY MODEL:
Option = Non Buoyant
END
DOMAIN MOTION:
Option = Stationary
END
MESH DEFORMATION:
Option = None
END
REFERENCE PRESSURE:
Reference Pressure = 0 [atm]
END
END
FLUID DEFINITION: mix
Option = Material Definition
MATERIAL DEFINITION:
Option = Reacting Mixture
END
MORPHOLOGY:
Option = Continuous Fluid
END
END
FLUID MODELS:
COMBUSTION MODEL:
Option = Finite Rate Chemistry
Reactions List = Methane Air WD1
END
COMPONENT: CH4
Option = Transport Equation
END
COMPONENT: CO2
Option = Transport Equation
END
COMPONENT: H2O
Option = Constraint
END
COMPONENT: O2
Option = Transport Equation
END
HEAT TRANSFER MODEL:
Include Viscous Dissipation Term = Off
Option = Thermal Energy
END
THERMAL RADIATION MODEL:
Option = None
END
TURBULENCE MODEL:
Option = Laminar
END
END
END
INITIALISATION:
Option = Automatic
INITIAL CONDITIONS:
Velocity Type = Cartesian
CARTESIAN VELOCITY COMPONENTS:
Option = Automatic
END
COMPONENT: CH4
Option = Automatic
END
COMPONENT: CO2
Option = Automatic
END
COMPONENT: O2
Option = Automatic
END
STATIC PRESSURE:
Option = Automatic
END
TEMPERATURE:
Option = Automatic with Value
Temperature = 1500 [K]
END
END
END
OUTPUT CONTROL:
MONITOR OBJECTS:
MONITOR BALANCES:
Option = Full
END
MONITOR FORCES:
Option = Full
END
MONITOR PARTICLES:
Option = Full
END
MONITOR POINT: recirculation zone temp
Cartesian Coordinates = 0.005 [m], 0.0005 [m], 0 [m]
Coord Frame = Coord 0
Option = Cartesian Coordinates
Output Variables List = Temperature
MONITOR LOCATION CONTROL:
Interpolation Type = Nearest Vertex
END
POSITION UPDATE FREQUENCY:
Option = Initial Mesh Only
END
END
MONITOR RESIDUALS:
Option = Full
END
MONITOR TOTALS:
Option = Full
END
END
RESULTS:
File Compression Level = Default
Option = Standard
END
END
SOLVER CONTROL:
ADVECTION SCHEME:
Option = High Resolution
END
CONVERGENCE CONTROL:
Length Scale Option = Conservative
Maximum Number of Iterations = 100
Minimum Number of Iterations = 1
Timescale Control = Auto Timescale
Timescale Factor = 1.0
END
CONVERGENCE CRITERIA:
Conservation Target = 0.001
Residual Target = 1e-06
Residual Type = RMS
END
DYNAMIC MODEL CONTROL:
Global Dynamic Model Control = Yes
END
MCF ENERGY DIFFUSION:
Option = Unity Lewis Number
END
END
END
COMMAND FILE:
Version = 16.2
END
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Old   February 1, 2016, 17:02
Default
  #4
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Glenn Horrocks
Join Date: Mar 2009
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Have you seen this FAQ? http://www.cfd-online.com/Wiki/Ansys...hemistry_model

Also: You do not appear to have a radiation model. Isn't this important at these temperatures?
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Old   February 1, 2016, 18:00
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Opaque will become famous soon enough
May I ask how you computed the adiabatic flame temperature for the specific case you are solving ?

The adiabatic flame temperature is not a universal value though many engineers take it as such because it refers to a standard condition in their minds. If by any chance you are referring to results computed by some chemical equilibrium codes, there is the first problem. Those codes usually refer to air-methane (while you are doing oxygen-methane only); therefore, the presence of N2 drops the adiabatic temperature considerably. I think 6000+ [K] is still high, but if the solution converged, the adiabatic flame temperature is determined by pure thermodynamics, i.e. enthalpy balances and not CFD.

What are the conditions for the adiabatic flame temperature value you are reporting ? Are there other species for such conditions ?

Hope the above helps,
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