heat exchanger

S K Prasad

Hi, I'm looking for a formulation to find the overall heat transfer coefftts for heat exchangers. As far as i know, the experssion is analogous to electrical resistance in series and is given by,

1/Uavg*A = 1/(hA)hot + 1/(hA)cold + 1/(UA)metal.

I'm looking for an experssion for convective heat transfer coefficient, h as a function of local fluid properties like velocity, temperature etc. I hope the expression should be unique for the type of heat exchanger like cross flow unmixed, parallel flow etc. I'm not sure. Can anybody help me with this. thanks in advance.