HEAT TRANSFER ENHANCEMENT AND FRICTION FACTOR ANALYSIS IN TUBE USING CONICAL SPRING INSERT

Abstract

Role of the conical spring array for the heat transfer enhancement and pressure drop change in a pipe with constant heat flux boundary condition was investigated. Three different arrangements of conical spring array inserts were used in the experimental setup. Conical spring inserts with diverging conical spring, converging-diverging conical spring and converging conical spring array inserts arrangements were used. Water was used as a working fluid in the experimental setup. It was found that use of conical spring array inserts arrangement leads to enhancement in heat transfer. Higher heat transfer rate was achieved in the divergent spring array arrangement than the converging-diverging and converging arrangement. However, maximum friction factor is achieved in the diverging spring array insert arrangement. By increasing the Reynolds Number for different turbulator arrangement, the significant increase in Nusselt number was obtained. The enhancement in Nusselt Number for the diverging, converging-diverging, converging conical spring array arrangement was 645% ,431% and 259% respectively. The heat transfer enhancement efficiency can be evaluated based on the power consumption per unit mass of fluid. Heat transfer enhancement efficiencies were found for the divergent spring array arrangement up to 277% and for the convergent-divergent spring arrangement up to 212% and for the convergent spring array arrangement up to 153%.