The inner pipe of a double-pipe heat exchanger has an OD of 1.9 in. and contains 36 rectangular fins of the type shown in the sketch below. The fins are made of steel (k=34.9 Btu/h ? ft ? ?F) and are 0.5 in. high and 0.035-in. thick. The pipe wall temperature is 250F and the fluid in the annulus surrounding the fins is at 150?F with a heat-transfer coefficient of 30 Btu/h · ft2 F. Calculate:
A) Calculate the fin parameter (n)
B) The fin effectiveness
C) The fin efficiency
D) The heat transfer rate from one fin per foot of pipe length
E) The temperature on the tip (x=L)
F) The heat duty for the exchanger is 390,000 Btu/h. What length of pipe is required to satisfy this duty?
G) The total rate of heat transfer (from fins and no-fin surface)