Heat Transfer coefficients

[Tkian]

Dear all,

I presently doing some investigation on a 2 flow (upper & lower)solar air collector. Can anyone tell me how to find the convection heat transfer coefficients h for the surfaces in the flow channel.

thanks in advance

regards,
tkian

 

[Biggadike]

The rate of heat transfer 'q' due to convection at a surface between a fluid and another substance is well modelled in the steady state by:

q=hA(theta1-theta2)

Where A is the area of the surface, h is a positve constant called the 'convective heat transfer coefficient' The temperature theta1 is the higher temp (surface of substance or ambient fluid temp) and the temp. theta2 is the lower of these two.

This is taken from an OU publication MST207

h takes into account the suface finish and the nature of the fluid. Now you need to establish h for your situation.

Hope that helps.