How to define a specific heat function using usr_properties?

MFiX How to
#1

Hi
I want to use the usr_properties to difine a Cp of solid particle:
i.e.

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%E5%9B%BE%E7%89%871248×27 10 KB

I copied the source code of usr_properties.f to my directory, and I found this line:
C_PS(IJK,M) =
But how to represent the Temperature in the formula?

The variable, which I only know, to represent solid temperature is des_T_s(NP), however there is no NP(the particle index).

Thank you

#2

USR_PROP_CPs(ijk,M) is used to define the CPs for each solid phase. If you want to include the temperature effect in CPs, just:

USE fldvar, only: T_S
USE physprop, only: C_PS
…
! sand
IF(M=1) C_PS(ijk,M)= …
! wood
IF(M=2) C_PS(ijk,M)=1112.0+4.85(T_S-273)

If you want to simulate the chemical reaction of wood particles using DEM model (wood–>char+ash+unreacted wood+gas), the CPs of a particle is also a function of species, thus I suggest you try an easier way as follows:

  1. select a solid (e.g. C) from the BURCAT database to mimic wood, ash, char, respectively.
  2. Modify the Cp (eg. wood: 1112.0+4.85(T_S-273)) in the following format.
    Cp/R=a1+a2T+a3T^2+a4T^3+a5T^4
2 Likes
#3

Hi @chunlei @gaoxi
I am also meeting this problem. What does R in format Cp/R=a1+a2T+a3T^2+a4*T^3+a5* T^4 refer to? Gas constant, 8314 J/kmol/k？

#4

R is the gas constant, 8.3145J