Afinned – tube, cross flow heat exchanger (both fluids unmixed)is designed to cool oilwhich enters at 100 ºc and 2 kg/s. cold water is used for this duty which enters at 20 ºc and 0.48 kg/s. determine:
a) the exit temperature of the water.
b) the exit temperature of the oil.
c) the heat transfer rate.
hint: 1) use the suitable equation to calculate the effectiveness (do not use any figure).
2) use eqn. (11.20) and eqn.(11.21) to find the fluid outlet temperatures
data
oil heat capacity, cp = 2.0 kj /kg°c
water heat capacity, cp = 4.170 kj /kg°c
overall heat transfer coefficient u = 400 w/m2.k
surface area of the heat exchanger = 12.5 m2