User defined specific heat capacity

lost.identity · November 8, 2012, 09:59

Hi,

I'm doing a reacting flow simulation with tabulated chemistry (i.e. using a flamelet model). I use a progress variable, c, to represent the mixture thermo-chemistry. The look-up tables and the transport equations are of my own and not the the Star-CD's built-in ones.

The Cp values are tabulated as well and I use the subroutine SPECHT to obtain Cp. I use static enthalpy conservation equation with thermal enthalpy. I'm not sure if this method will give me the correct temperature as I seem to have ignored the chemical enthalpy whilst doing so.

Or does this mean I have to define the enthalpy in a user subroutine as well?

Thanks!

lost.identity · November 13, 2012, 10:34

I haven't been able to set this reacting flow case yet. In pro-STAR setup I set Reacting Flow to None since I will be setting up my own equations.

I define additional scalars required and their source terms as user defined subroutines. I do turn on the temperature calculation using static-enthalpy conservation equation.

I obtain $\overline{C_p}$ from my flamelet table. At the moment I have two problems,

1. I used SPECHT to obtain $\overline{C_p}$ from my look-up table, however this is only done at the start of the simulation and hence does not update after each time step.

2. There doesn't seem to be any link between the progress variable and temperature in my code, therefore my progress variable just diffuses with time.

How does one couple the progress variable and temperature? Any references will be helpful.

Thanks!

hatef · May 17, 2013, 00:42

To put it into simple words, are you trying to get temperature dependent Cp from tabulated data?

November 8, 2012, 09:59	User defined specific heat capacity	#1
lost.identity Senior Member Join Date: Apr 2009 Posts: 118 Rep Power: 17	Hi, I'm doing a reacting flow simulation with tabulated chemistry (i.e. using a flamelet model). I use a progress variable, c, to represent the mixture thermo-chemistry. The look-up tables and the transport equations are of my own and not the the Star-CD's built-in ones. The Cp values are tabulated as well and I use the subroutine SPECHT to obtain Cp. I use static enthalpy conservation equation with thermal enthalpy. I'm not sure if this method will give me the correct temperature as I seem to have ignored the chemical enthalpy whilst doing so. Or does this mean I have to define the enthalpy in a user subroutine as well? Thanks! Last edited by lost.identity; November 8, 2012 at 10:24.

May 17, 2013, 00:42	Reading Cp from table	#3
hatef New Member Hatef Khadivinassab Join Date: Jan 2013 Posts: 6 Rep Power: 13	To put it into simple words, are you trying to get temperature dependent Cp from tabulated data?

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November 13, 2012, 10:34		#2
lost.identity Senior Member Join Date: Apr 2009 Posts: 118 Rep Power: 17	I haven't been able to set this reacting flow case yet. In pro-STAR setup I set Reacting Flow to None since I will be setting up my own equations. I define additional scalars required and their source terms as user defined subroutines. I do turn on the temperature calculation using static-enthalpy conservation equation. I obtain $\overline{C_p}$ from my flamelet table. At the moment I have two problems, 1. I used SPECHT to obtain $\overline{C_p}$ from my look-up table, however this is only done at the start of the simulation and hence does not update after each time step. 2. There doesn't seem to be any link between the progress variable and temperature in my code, therefore my progress variable just diffuses with time. How does one couple the progress variable and temperature? Any references will be helpful. Thanks!