Lee evaporation model gives unrealistic wall superheating

marcusaurelius · February 28, 2024, 03:53

I am using Lee evaporation model to simulate saturated pool boiling case for dielectric fluid. I am using constant wall heat flux boundary condition.

When, I am plotting Heat flux vs Wall superheating, I am getting unrealistic too high wall superheating compared to the experimental value.

For example, at heat flux of 200 kW/m2, the wall superheating should be 14 °C, But I am getting around 145°C of superheating.

I know the lee coefficient is sensitive here. I did trial and error with different values ranging from 0.1 to 1000 but, the wall superheating never goes near to 14°C, it is always above 100° (which is unrealistic).

How do I deal with this issue?

Jonathan · March 20, 2024, 12:44

I guess there could be quite a few more parameter apart from simply the Lee coefficient which might be important ...

How are you modelling the bubbles, interfacial area, lift and drag / buoyancy forces?

marcusaurelius · March 21, 2024, 07:20

Thank you for the reply. But, I have been able to manage the wall superheating near to realistic values by adding solid wall (conduction).

February 28, 2024, 03:53	Lee evaporation model gives unrealistic wall superheating	#1
marcusaurelius New Member marcus aurelius Join Date: Sep 2023 Posts: 18 Rep Power: 3	I am using Lee evaporation model to simulate saturated pool boiling case for dielectric fluid. I am using constant wall heat flux boundary condition. When, I am plotting Heat flux vs Wall superheating, I am getting unrealistic too high wall superheating compared to the experimental value. For example, at heat flux of 200 kW/m2, the wall superheating should be 14 °C, But I am getting around 145°C of superheating. I know the lee coefficient is sensitive here. I did trial and error with different values ranging from 0.1 to 1000 but, the wall superheating never goes near to 14°C, it is always above 100° (which is unrealistic). How do I deal with this issue?

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March 20, 2024, 12:44		#2
Jonathan Senior Member Join Date: Mar 2010 Posts: 181 Rep Power: 17	I guess there could be quite a few more parameter apart from simply the Lee coefficient which might be important ... How are you modelling the bubbles, interfacial area, lift and drag / buoyancy forces?

March 21, 2024, 07:20		#3
marcusaurelius New Member marcus aurelius Join Date: Sep 2023 Posts: 18 Rep Power: 3	Thank you for the reply. But, I have been able to manage the wall superheating near to realistic values by adding solid wall (conduction).