Is there a bug in externalWallHeatFluxTemperature boundary condition ?

Pavithra · September 19, 2021, 19:06

Hi Everyone,

I am simulating evaporation/condensation using icoReactingMultiphaseInterFoam. I need to apply a uniform heat flux boundary condition over a wall. Hence, I chose to use externalWallHeatFluxTemperature boundary condition. But, my temperatures were very high and unphysical. Then, I plotted the wall heat flux and found that they are very high than the values I set. Is it a bug in externalWallHeatFluxTemperature boundary condition ?

I am aware that I could use fixedGradient = heat flux/kappa. But, as I am working on a multiphase flow getting the right value of kappa is a bit complex. However, I am working on groovyBC to use a gradient Expression with the expression of kappa.

But, still externalWallHeatFluxTemperature boundary condition would be a straight forward solution for me.

Kindly please advice me on this.

Thank You.

With Thanks,
Pavithra.

JulioPieri · January 12, 2022, 15:35

I've been using this BC for long time without bug. However it is hard get proper variables, as you have many influencing parameters. I'd recommend going back to paper and pen and see if the heat balance of you walls make sense.

If you are using qr, then it's very important to use qrRelaxation

September 19, 2021, 19:06	Is there a bug in externalWallHeatFluxTemperature boundary condition ?	#1
Pavithra Member Join Date: Apr 2019 Location: India Posts: 81 Rep Power: 7	Hi Everyone, I am simulating evaporation/condensation using icoReactingMultiphaseInterFoam. I need to apply a uniform heat flux boundary condition over a wall. Hence, I chose to use externalWallHeatFluxTemperature boundary condition. But, my temperatures were very high and unphysical. Then, I plotted the wall heat flux and found that they are very high than the values I set. Is it a bug in externalWallHeatFluxTemperature boundary condition ? I am aware that I could use fixedGradient = heat flux/kappa. But, as I am working on a multiphase flow getting the right value of kappa is a bit complex. However, I am working on groovyBC to use a gradient Expression with the expression of kappa. But, still externalWallHeatFluxTemperature boundary condition would be a straight forward solution for me. Kindly please advice me on this. Thank You. With Thanks, Pavithra.

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January 12, 2022, 15:35		#2
JulioPieri Member Julio Pieri Join Date: Sep 2017 Posts: 96 Rep Power: 8	I've been using this BC for long time without bug. However it is hard get proper variables, as you have many influencing parameters. I'd recommend going back to paper and pen and see if the heat balance of you walls make sense. If you are using qr, then it's very important to use qrRelaxation