Heat Transfer Characteristics of Inclined Helical Coil Tube by Forced and Free Convection : A Review

Aim of this review work is to examine the relative advantage of using an inclined helical coil tube heat exchanger for high-pressure syngas under various industries application. It observed that the heat transfer in the helical coil tube is higher as compared to the straight tube due to their shape. Inclined helical coil tube heat exchanger offers advantageous over straight tubes due to their compactness and increased heat transfer coefficient. The increased heat transfer coefficients are a consequence of the curvature of the coil, which induces centrifugal forces to act on the moving syngas. Due to the curvature effect, the fluid streams in the outer side of the pipe moves faster than the syngas streams on the inner side of the tube. Heat transfer augmentation techniques refer to various methods used to increase the heat transfer rate without changing much the overall performance of the system. The arrangements are useful in a variety of applications where more heat transfer rates desired. Some of the claims involved in heat exchanger used in Thermal Power plants, process industries, air-conditioning equipment, heating and cooling in evaporators, radiators for space vehicles, automobiles, refrigerators. These techniques broadly of three types viz. passive, active, compound heat transfer augmentation techniques. The present paper reviews the experimental investigation of free and forced convection heat transfer from different helical coiled tubes.