Numerical studies on heat transfer characteristics of double pipe and helical coil heat exchangers

Abstract The heat transfer properties of Helical Coil Heat Exchangers and Double Pipe Heat Exchangers are compared in this study utilizing both water and nanofluids. A three-dimensional numerical simulation assessed the heat transfer performance of both designs under equivalent heat transfer areas and fluid flow circumstances. The present study employed CFD to compare helical-coil and double-pipe heat exchangers under conditions of area-normalized, equal-Reynolds-number, and counter-current flow. The two types of exchangers are tested under the same boundary conditions in an industrially relevant hot-side temperature range. In the present study it may be observed that, the differences in performances caused by geometry while maintaining the total heat-transfer area (0.77 m 2 ) and flow parameters the same. The incorporation of 1% Al 2 O 3 nanofluid in the tube side significantly enhanced heat transmission rates. The results demonstrate that the helical coil configuration exhibited a significantly enhanced overall heat transfer coefficient, improving by as much as 60% relative to the double pipe configuration. The tube side is compatible with or without 1 vol% Al 2 O 3 –H 2 O nanofluid. The study emphasizes the influence of differing operating temperatures and fluid velocities, with Helical Coil Heat Exchanger consistently surpassing Double Pipe Heat Exchangers under all evaluated situations. In comparison the overall heat-transfer coefficient (U) has been found to be higher up to 60% for helical-coil heat exchanger than that of the double-pipe heat exchanger. The improved heat transmission in Helical Coil Heat Exchanger is due to its coiled design, which facilitates secondary flow and turbulence and hence optimizes thermal efficiency. As a result, the results show that Helical Coil Heat Exchanger using nanofluids works well for tasks that need better heat transfer efficiency, offering many advantages over standard double pipe arrangements.