Operating conditions and geometry of a counter flow double p

Operating conditions and geometry of a counter flow double pipe heat exchanger is as follows: Tube material is copper (400 W/m-K) with wall thickness of 1 mm. Calculate the following: a) What is the total heat transfer resistance? b) What is the overall heat transfer coefficient - U? c) Which side (tube or shell) has a higher resistance? d) What is the NTU? e) What is the effectiveness? f) What is the heat transfer rate, q? g) What are the outlet temperatures? h) What is the LMTD?

Solution

A. THE TOTAL HEAT TRANSFER RESISTANCE can be done by usinng the basic heat exchanger equation Q = UA*DELTA T ln

where q = the rate of heat exchanger betweeen the two fluids in the heat exchanger

u = the overallheat transfer surface area

del t = the log mean temperature difference

B. The overall heat transfer is the proportionallly coefficient betweeen the heat flux and the thermodynamic driving force for the heat flow of heat

h = q / (Ts - K)

where Ts = solid surface temperature

K = surrounding fluid area temperature