August 30, 2022 at 11:51 ammardottSubscriber
I want to assign a temperature dependent heat capacity to my DPM particles.
I've therefore been trying with the following UDF:
DEFINE_DPM_PROPERTY(DPMaterial_Cp, c, t, tp, T)
real Cp; /* Heat Capacity - Cp J/(kgK) */
if (NULLP(tp->pp) || NULLP(TP_CELL_THREAD(tp)))
Cp = 320; /* J/(kgK) initial value for T = 1100 */
Cp = 450.60 - 116.10*pow(10.,-3.)*T - 166.79*pow(10.,5.)*pow(T,-2.);
tp->enthalpy = Cp * (T - T_REF);
THe UDF compiles, and the DPM iterates for a few times, but then the simulation crashes (only when this UDF is implemented).
What am I doing wrong?
August 30, 2022 at 3:55 pmRobAnsys Employee
Check the value of cp that's being returned for the temperature range in your model. Plot cp with T using the above relationship, how does it look?
August 30, 2022 at 4:15 pmmardottSubscriber
This happens even if the flow temperature makes sense
Leading to what it probably is the cause of the crash: a negative Cp (but for the range of T that I should have it would surely be positve)
The question now is: how is it possible that my particles get such a low temperature in some sparse points?
August 31, 2022 at 2:34 pmRobAnsys Employee
Depending on the mass of the parcel and cell size if you evaporate quickly the DPM source terms can become high, and that can cause problems with the flow (cell) values. How many parcels are you releasing, and how does the mass (and volume) fraction look?
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