Pengujian Karakteristik Perpindahan Panas Danpenurunan Tekanan Sirip-Sirip Pin Ellips Susunan Selang-Seling Dalam Saluran Segiempat

Abstract

Abstract : This research was conducted to investigate the characteristics of heat transfer and pressure drop as well as the thermal performance of elliptical pin fin array in the rectangular channel which air was passed through it as coolant fluid. The pin fins were arranged in staggered manner. Dimension of base plate in which pin fins were attached was 150 mm x 200 mm x 6.5 mm. The average temperature of base plate surface was kept constant at 60oC. Pin fins were made of duralumin having the dimension of 75 mm of height, the major and minor axis length of the elliptical pin fin 15 mm and 6 mm respectively, and the distance inter-fin picth in the spanwise direction was kept constant at Sx/Dπ,= 3.57. The parameters of this research were Reynolds number (Re) 3,152 – 37,879 based on averaged inlet air velocity and hydraulic diameter of rectangular channel, and the distance between the inter-fin pitch in the streamwise direction (Sy/Dπ =2.38 – 4.76) The research result shown that increasing Reynolds number and decreasing the distance Sy/Dp increased Nusselt number (Nu), that means increased heat transfer rate where it reach maximum at Sy/Dπ =2.38. The values of pressure drop (DP) and friction factor (f) decreased with increasing Sy/Dp. Thermal performance decreased with increasing Reynolds number. The thermal performances (h) varied between 0.84 – 1.52. For Sy/Dp = 3.57 at Re > 37,965 and Sy/Dp = 4.76 at Re > 25,240, the thermal performance value is less than 1 and varied between 0.76 - 0.97. At Sy/Dp = 2.38 produced the highest of thermal performances for the whole of Re. A net energy gain can be achieved up to 52% for the value of Sy/Dp = 2.38 and Re =3,132.

Keywords : Elliptical Pin Fin, Friction Factor, Nusselt Number, Reynolds Number, Thermal Performance