Heat Transfer Coefficient of air vs Velocity

shreesha87 · May 28, 2014, 15:20

Hello everyone

I have a question about forced convective heat transfer. I read on many websites that one of the major contributors in forced convection is the velocity of air. Higher the velocity of air, higher the heat transfer coefficient.Usually, they say that h (heat transfer coefficient) is proportional to square root of the the velocity. But, there should be a limit to the "h" value right?

Can I increase the velocity really high (sonic, supersonic) and get very high values for the heat transfer coefficient?

Thanks
Shree

ahmed_khatibs · May 29, 2014, 02:48

check this:

http://www.engineeringtoolbox.com/co...fer-d_430.html

regards,
Ahmed Khatib

shreesha87 · May 29, 2014, 14:58

Hi Ahmed

Thanks for the reply. The link that you gave me has an empirical formula for h w.r.t. velocity which is valid only for velocities in the range 0 - 20 m/s.

What is the velocity is the range 100-300 m/s?

Thanks
Shreesha

ahmed_khatibs · May 30, 2014, 02:10

You may get some more information in this paper.

http://msdssearch.dow.com/PublishedL...romPage=GetDoc

regards,
Ahmed Khatib

May 28, 2014, 15:20	Heat Transfer Coefficient of air vs Velocity	#1
shreesha87 New Member Join Date: Oct 2013 Posts: 13 Rep Power: 12	Hello everyone I have a question about forced convective heat transfer. I read on many websites that one of the major contributors in forced convection is the velocity of air. Higher the velocity of air, higher the heat transfer coefficient.Usually, they say that h (heat transfer coefficient) is proportional to square root of the the velocity. But, there should be a limit to the "h" value right? Can I increase the velocity really high (sonic, supersonic) and get very high values for the heat transfer coefficient? Thanks Shree

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May 29, 2014, 02:48		#2
ahmed_khatibs Member ahmed Join Date: Sep 2011 Location: Pune-INDIA Posts: 34 Rep Power: 14	check this: http://www.engineeringtoolbox.com/co...fer-d_430.html regards, Ahmed Khatib

May 29, 2014, 14:58		#3
shreesha87 New Member Join Date: Oct 2013 Posts: 13 Rep Power: 12	Hi Ahmed Thanks for the reply. The link that you gave me has an empirical formula for h w.r.t. velocity which is valid only for velocities in the range 0 - 20 m/s. What is the velocity is the range 100-300 m/s? Thanks Shreesha

May 30, 2014, 02:10		#4
ahmed_khatibs Member ahmed Join Date: Sep 2011 Location: Pune-INDIA Posts: 34 Rep Power: 14	You may get some more information in this paper. http://msdssearch.dow.com/PublishedL...romPage=GetDoc regards, Ahmed Khatib