Modeling Heat Flux using FLUENT

ankurgahlot · May 20, 2009, 08:43

I am trying to model a solar collector (using air as fluid) in FLUENT. Right now I am giving a constant temperature to the collector plate and using that to get the air flow pattern.

I want to make it a bit more realistic and use heat flux in place of the constant temperature. The energy at the earth's surface from the sun is available in solar data. So, I am giving it a heat flux of around 700 w/m2.

But the temperature reached in this case is around 400 - 500 kelvin which is unrealistic.

Currently I am using boussinesq approximation and laminar flow.

What else do I need to include in this ?
Could anybody please help me with this.
Thanks

laura_c · April 18, 2013, 03:46

i am experienceing the same problem... but i m using ideal-gas modelling... how did you manage to solve it? thanks

dklastiwka · April 20, 2013, 10:17

We would need more information to solve the problem. Can you send the model and give the reference for the heat flux of 700 W/m^2?

miguel.soto · September 25, 2013, 15:14

I´m dealing with a similar issue as ankurgahlot and laura_c.

My case is a forced convection heat transfer, for an alternator cooling. The alternator heat flux to the surrounding air is 1050 W/m^2, and the upstream air velocity is set as 15m/s. The alternator boundary thermal conditions are set as heat flux (I also considered to set thermal conditions as temperature, but alternator´s temperature is what i´m trying to know).The solution convergence is acceptable, but the alternators temperature solution is too high, it reaches 5000 K, this value is out of context. The experimental test data shows that the maximum alternator temperature is around 373 K.

does anybody knows what we are doing wrong?

Thanks in advance

May 20, 2009, 08:43	Modeling Heat Flux using FLUENT	#1
ankurgahlot New Member Ankur Gahlot Join Date: May 2009 Posts: 1 Rep Power: 0	I am trying to model a solar collector (using air as fluid) in FLUENT. Right now I am giving a constant temperature to the collector plate and using that to get the air flow pattern. I want to make it a bit more realistic and use heat flux in place of the constant temperature. The energy at the earth's surface from the sun is available in solar data. So, I am giving it a heat flux of around 700 w/m2. But the temperature reached in this case is around 400 - 500 kelvin which is unrealistic. Currently I am using boussinesq approximation and laminar flow. What else do I need to include in this ? Could anybody please help me with this. Thanks

April 20, 2013, 10:17		#3
dklastiwka New Member Derek Lastiwka Join Date: Feb 2010 Location: Calgary, Alberta, Canada Posts: 26 Rep Power: 16	We would need more information to solve the problem. Can you send the model and give the reference for the heat flux of 700 W/m^2? __________________ Derek Lastiwka Mechanical & Fluids Engineer dlastiwka@graymattereng.com Gray Matter Engineering Inc.

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April 18, 2013, 03:46		#2
laura_c New Member Laura Join Date: Apr 2013 Posts: 15 Rep Power: 13	i am experienceing the same problem... but i m using ideal-gas modelling... how did you manage to solve it? thanks

September 25, 2013, 15:14		#4
miguel.soto New Member miguel Join Date: Jan 2010 Posts: 11 Rep Power: 16	I´m dealing with a similar issue as ankurgahlot and laura_c. My case is a forced convection heat transfer, for an alternator cooling. The alternator heat flux to the surrounding air is 1050 W/m^2, and the upstream air velocity is set as 15m/s. The alternator boundary thermal conditions are set as heat flux (I also considered to set thermal conditions as temperature, but alternator´s temperature is what i´m trying to know).The solution convergence is acceptable, but the alternators temperature solution is too high, it reaches 5000 K, this value is out of context. The experimental test data shows that the maximum alternator temperature is around 373 K. does anybody knows what we are doing wrong? Thanks in advance