Residuals aren't converging

aerok_25 · April 8, 2024, 10:15

Hi ,
I am currently trying to run simulations on a fin and streamline tube heat exchanger with 2 million cells and I am facing an issue with the residuals not converging.

Boundary Conditions
1. K-Epsilon Model
2. Air and Hydrogen-liquid
3. Mass Flow Inlet
4. SIMPLE
5. 1e-08
6. Hybrid Initialization
7. 2000 iterations

If anyone can let me know what can I do for better residuals would be really helpful

Gert-Jan · April 11, 2024, 09:34

1. I would ask the Fluent Forum
2. What is your Re-number? K-epsilon is for high Re numbers. Better use SST.
3. Your flow problem will have transient features. You'll never be able to obtain a steady state solution.
4. If you want a steady state solution, limit you geometry to a very thin gap that slices the obstacles in half.

aerok_25 · April 11, 2024, 09:55

I used a mass flow inlet with the following variables..

Air
1. Mass Flow = 11.25
2. Gauge Pressure = 105700
3. Temperature = 344K

Hydrogen
1. Mass Flow = 0.1022
2. Gauge Pressure = 1571000
3. Temperature = 24K

Gert-Jan · April 17, 2024, 03:45

What do you want to say with this reply?

April 11, 2024, 09:55	Boundary Condition	#3
aerok_25 New Member Brendan Join Date: Apr 2024 Posts: 2 Rep Power: 0	I used a mass flow inlet with the following variables.. Air 1. Mass Flow = 11.25 2. Gauge Pressure = 105700 3. Temperature = 344K Hydrogen 1. Mass Flow = 0.1022 2. Gauge Pressure = 1571000 3. Temperature = 24K

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April 11, 2024, 09:34		#2
Gert-Jan Senior Member Gert-Jan Join Date: Oct 2012 Location: Europe Posts: 1,827 Rep Power: 27	1. I would ask the Fluent Forum 2. What is your Re-number? K-epsilon is for high Re numbers. Better use SST. 3. Your flow problem will have transient features. You'll never be able to obtain a steady state solution. 4. If you want a steady state solution, limit you geometry to a very thin gap that slices the obstacles in half.

April 17, 2024, 03:45		#4
Gert-Jan Senior Member Gert-Jan Join Date: Oct 2012 Location: Europe Posts: 1,827 Rep Power: 27	What do you want to say with this reply?