A stainless steel pipe (3 m in length), carries hot air in an air conditioning, system. It is proposed to use straight triangular fins as part of exchanger walls in order to transfer heat to a pool water and hence cooling the air. The heat transfer coefficient is equal to 2271.3 W/ (m2.K) and the pool temperature is 15°C. The base wall temperature of the heat exchanger is maintained at 88°C. Determine the number of fins and dimensions of each fin in order to achieve a total heat transfer rate of 6374 W.

Note#1: we can’t assume that the entire circumference of pipe is coverd with fins So there will be q( unfin)

Note#2: we can’t assume that( t ) is very small compared with (w ) ( so we can’t use the efficiency of rectangular

Note#3: we will use this chart to find the value of the efficiency.

100 80 A 2wL+ 60 A DL+D) 20 0.5 1.0 1.5 2.0 25 Fia efficieney e percent