Heat Transfer Coefficients and Pressure Drops Analyses for Helical Coil Heat Exchanger at Various Velocities and Concentrations of Al2O3: by CFD

Abstract

Helical coil heat exchangers (HCHExs) are one of the most universal equipments found in various industrial applications which are used as heat recovery systems. Improving the heat transfer (HT) characteristic by helical coils has been studied in this work because the fluid dynamics inside the pipes of HCHEx offer definite advantages over the straight tubes. Various coil structure configurations are possible and series of vertically stacked helically coiled tubes is the most common type. In this paper, analytical studies were conducted for counter flow HCHEx with eight helical coils. Two different analyses were conducted, one where water is used as HT fluid on the coil and shell sides; second where different volume fractions of Al2O3 and water are used on the coil and shell sides respectively. Reynolds numbers (Re), heat transfer coefficients (HTCs) and pressure drops (PDs) were found at
different velocities of nano fluids. From outcomes, it was observed that maximum PD found with pure water and as percentage of Al2O3 increases then PD increases at the same velocity of fluid. This work is also concluded as when velocity increases then HTC increases with PD.