GeorgeEllwood
Mechanical
Hello,
I'm trying to create a thermal transient model using a material that has non linear specific heat capacity which also changes dramatically, i.e. at 4k the specific heat capacity is .34 J/kg.k at 100k it is 104 J/kg.k. I've been advised that it might be easier and help convergence if I used enthalpy instead of heat capacity. I believe ANSYS requires specific enthalpy J/m^3. I've tried to convert my specific heat capacity to specific enthalpy by multiplying by the density and then integrating with respect to temperature to give me a set of values of enthalpy versus temperature.
I've tried running a simple model with these enthalpy values but it isn't converging, when I look at the unconverged solution the temperature is higher than earlier results using specific heat capacity.
Would any body be able to advise on what I'm doing wrong? Or give some general guidance on using ANSYS and enthalpy?
Many thanks
George
I'm trying to create a thermal transient model using a material that has non linear specific heat capacity which also changes dramatically, i.e. at 4k the specific heat capacity is .34 J/kg.k at 100k it is 104 J/kg.k. I've been advised that it might be easier and help convergence if I used enthalpy instead of heat capacity. I believe ANSYS requires specific enthalpy J/m^3. I've tried to convert my specific heat capacity to specific enthalpy by multiplying by the density and then integrating with respect to temperature to give me a set of values of enthalpy versus temperature.
I've tried running a simple model with these enthalpy values but it isn't converging, when I look at the unconverged solution the temperature is higher than earlier results using specific heat capacity.
Would any body be able to advise on what I'm doing wrong? Or give some general guidance on using ANSYS and enthalpy?
Many thanks
George
