high Temperature shoot up and high mach flow.

skdubey · February 16, 2022, 21:32

Dear Friend,

I was solving the airflow through the Tangle, in order to solve the problem, I choose the flowing fluid as "air" as compressible fluid. I am doing this as a control experiment. Pinlet (Gauge Pressure) :3 atm and Pout(Gauge Pressure) is 1atm. The temperature of the fluid is 300K (constant for inlet and outlet) .

Solver: Explicit, ROE and Grad: Node-based and Flow: Second upwind scheme.

Initialization: Hybrid

Steady-state problem:

Gravity: Y-axis :-9.81

Mach flow: Vel/Sqrt(1.4*287*Totat Temp) and Courant Number:1 and

I am not sure, why I am getting such a high temperature and Impossible Mach number through the T-channel. This result in the CFD post doesn't make any sense. I am not sure where I am making mistakes in defining the BC or meshing issue., solver, or anything else. Do I need to put any operating pressure, if I am just simulating for the flow at atmospheric conditions? any suggestion will be helpful.

Error shown by TUI for every iteration: Solver: " time step reduced in 707 cells due to excessive temperature change

temperature limited to 1.000000e+00 in 729 cells on zone 3

temperature limited to 5.000000e+03 in 961 cells on zone 3

200 1.8851e+00 5.7939e-01 8.1209e-01 7.1154e-01 8.3318e-01 0:00:00 0 "

For Picture please look into : https://forum.ansys.com/discussion/3...ch-flow#latest

Indra · February 19, 2022, 06:35

Looks like your problem has been solved in ANSYS forum.

But here's a tip, you can control the relaxation for your temperature as well with positivity rate limit under solution controls>limits. It's only available for density-based solver. But as mentioned in the forum, Pressure based will work just fine for transonic and low supersonic flows.

February 16, 2022, 21:32	high Temperature shoot up and high mach flow.	#1
skdubey New Member Sanjay Join Date: Mar 2020 Posts: 17 Rep Power: 6	Dear Friend, I was solving the airflow through the Tangle, in order to solve the problem, I choose the flowing fluid as "air" as compressible fluid. I am doing this as a control experiment. Pinlet (Gauge Pressure) :3 atm and Pout(Gauge Pressure) is 1atm. The temperature of the fluid is 300K (constant for inlet and outlet) . Solver: Explicit, ROE and Grad: Node-based and Flow: Second upwind scheme. Initialization: Hybrid Steady-state problem: Gravity: Y-axis :-9.81 Mach flow: Vel/Sqrt(1.4287Totat Temp) and Courant Number:1 and I am not sure, why I am getting such a high temperature and Impossible Mach number through the T-channel. This result in the CFD post doesn't make any sense. I am not sure where I am making mistakes in defining the BC or meshing issue., solver, or anything else. Do I need to put any operating pressure, if I am just simulating for the flow at atmospheric conditions? any suggestion will be helpful. Error shown by TUI for every iteration: Solver: " time step reduced in 707 cells due to excessive temperature change temperature limited to 1.000000e+00 in 729 cells on zone 3 temperature limited to 5.000000e+03 in 961 cells on zone 3 200 1.8851e+00 5.7939e-01 8.1209e-01 7.1154e-01 8.3318e-01 0:00:00 0 " For Picture please look into : https://forum.ansys.com/discussion/3...ch-flow#latest

February 19, 2022, 06:35		#2
Indra Member Void_CFD-user Join Date: Feb 2022 Posts: 67 Rep Power: 4	Looks like your problem has been solved in ANSYS forum. But here's a tip, you can control the relaxation for your temperature as well with positivity rate limit under solution controls>limits. It's only available for density-based solver. But as mentioned in the forum, Pressure based will work just fine for transonic and low supersonic flows.