Studi Eksperimental Pengaruh Bilangan Reynolds pada Koeffisien Perpindahan Panas Lokal Berkas Tabung Eliptik

The distribution of local heat transfer coefficient of a staggered elliptical tube bank is experimentally studied. The bank consists of 11 elliptical tube of 0,75 " equivalent diameter in 4-4-4 tubes arrangement. The major and minor sub axis are 24,70 mm and 12.35mm respectively, and therefore the Aspect ratio (AR) of the tube is 2.0. The geometry parameters of the bank are ST = 24.70 mm, SL = 37 mm and minimum frontal area B = 12.35 mm. Seven tubes are internally heated by electrical heater of 69.6 Watt each. Experiment is conducted in a sub sonic wind tunnel and run with the wind velocity of 1 m/s - 10 m/s. Results show that the first row tubes produce the lowest heat transfer coefficient, meanwhile the second row tubes posses the highest coefficient. The maximum value of local heat transfer coefficient is at the stagnation point of the second row tubes and the second highest is at the 'backward' stagnation point of the third row tubes.