The Effect of Geometrical Parameters on Heat Transfer and Hydro Dynamical Characteristics of Helical Exchanger

Abstract

Compact size and high heat transfer coefficient of helical coil heat exchangers causes them to have an important role in various industrial applications. This paper investigate numerically on the influence of different parameters such as coil radius, coil pitch and diameter of tube on the hydrodynamic and heat transfer characteristics of helical double tube heat exchangers using the CFD software which is based on the principles of heat transfer, fluid mechanics and thermodynamics. The results indicated that heat transfer augmentation occurs by increasing of the inner Dean Number, inner tube diameter, curvature ratio and by the reduction of the pitch of heat exchanger coil. By increasing the radius of coils, the secondary flow effects due to centrifugal forces diminishes and flow of fluid through the coils tends to flow in a straight path and as a result, the friction coefficient decreases consequently.