massrate calculations in reactingFoam/fireFoam

muhsinkhan · March 13, 2017, 02:25

Hi all,

I have been spending much time on the calcuation of massrate using "phi" for the tutorials of reactingFoam and fireFoam but the results show that both of them are not in equilibrium in regards of the inlet,outlet,sides, etc., at the end of the simulation.
i.e.
For reactingFoam tutorial (OpenFoam220) at t = 0.3,

phi_air = -1.7343e-05

phi_fuel = -9.64752e-06

phi_outlet = 2.72191e-05

so, the following should be achieved,

phi_air + phi_fuel = phi_out

but

1.7343e-05+9.64752e-06 < 2.72191e-05.

2.699052e-05 < 2.72191e-05 is achieved.

Thanks for any help.

muhsinkhan · March 17, 2017, 08:20

Was able to find the solution by changing the courant number to 0.1, relTol to 0.01, the simulation achieved complete equilibrium at 0.6 seconds.

phi_inlet (air + fuel) = 2.699052e-05
phi_outlet = 2.69905e-05

March 13, 2017, 02:25	massrate calculations in reactingFoam/fireFoam	#1
muhsinkhan New Member Muhsin Khan Join Date: Feb 2016 Posts: 5 Rep Power: 10	Hi all, I have been spending much time on the calcuation of massrate using "phi" for the tutorials of reactingFoam and fireFoam but the results show that both of them are not in equilibrium in regards of the inlet,outlet,sides, etc., at the end of the simulation. i.e. For reactingFoam tutorial (OpenFoam220) at t = 0.3, phi_air = -1.7343e-05 phi_fuel = -9.64752e-06 phi_outlet = 2.72191e-05 so, the following should be achieved, phi_air + phi_fuel = phi_out but 1.7343e-05+9.64752e-06 < 2.72191e-05. 2.699052e-05 < 2.72191e-05 is achieved. Thanks for any help. Last edited by muhsinkhan; March 13, 2017 at 08:24.

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March 17, 2017, 08:20		#2
muhsinkhan New Member Muhsin Khan Join Date: Feb 2016 Posts: 5 Rep Power: 10	Was able to find the solution by changing the courant number to 0.1, relTol to 0.01, the simulation achieved complete equilibrium at 0.6 seconds. phi_inlet (air + fuel) = 2.699052e-05 phi_outlet = 2.69905e-05