Heat Transfer from airflow to concrete

Mary2788 · June 22, 2011, 06:19

Hi there,

I'm a relative novice to using Fluent and I wondered if somebody could give me some advice about a problem that I'm modelling.

I have a 2d setup with a channel of airflow beneath a block of concrete. Above the block of concrete is a second channel of air to represent a service floor, although there is currently no airflow in this space. I have defined the zones as fluids and a solid in gambit and I have set the airflow in the bottom channel to 0.1m/s and temp of 307K.

I was hoping to see the heat from the airflow move into the concrete and be stored, so the temperature should increase in the concreteover time. However, when I run the simulation the temperature across the whole space (including the concrete and service floor) stays at 307K and there is only variation of around 0.001K.

Please could somebody advise me as to where I am going wrong? Thanks for your help.

madhuvc · June 22, 2011, 11:43

is there significant temp. difference across inlet and outlet of the channels. what is the temperature of the channel wall( assuming you are modeling it as a wall). you can also verify your material assignment for different boundaries.

if you can do a rough hand calculation with respect to heat generated by the channel and heat required to heat the concrete, i guess you should be able to figure out.

hope i made some sense...

June 22, 2011, 06:19	Heat Transfer from airflow to concrete	#1
Mary2788 New Member Join Date: Jun 2011 Posts: 2 Rep Power: 0	Hi there, I'm a relative novice to using Fluent and I wondered if somebody could give me some advice about a problem that I'm modelling. I have a 2d setup with a channel of airflow beneath a block of concrete. Above the block of concrete is a second channel of air to represent a service floor, although there is currently no airflow in this space. I have defined the zones as fluids and a solid in gambit and I have set the airflow in the bottom channel to 0.1m/s and temp of 307K. I was hoping to see the heat from the airflow move into the concrete and be stored, so the temperature should increase in the concreteover time. However, when I run the simulation the temperature across the whole space (including the concrete and service floor) stays at 307K and there is only variation of around 0.001K. Please could somebody advise me as to where I am going wrong? Thanks for your help.

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June 22, 2011, 11:43		#2
madhuvc New Member MadhuVC Join Date: Feb 2011 Posts: 28 Rep Power: 15	is there significant temp. difference across inlet and outlet of the channels. what is the temperature of the channel wall( assuming you are modeling it as a wall). you can also verify your material assignment for different boundaries. if you can do a rough hand calculation with respect to heat generated by the channel and heat required to heat the concrete, i guess you should be able to figure out. hope i made some sense...