Performance improvement of a shell and helically coiled tube heat exchanger using spiral fins

This thesis study presents an innovative, low cost, and easily applicable design to enhance the thermal performance of conventional shell and helically coiled tube heat exchangers. In the developed design, spiral fins have been added around the helical tube through which the hot fluid flows, and cold fluid's flow over this tube is provided to increase heat transfer efficiency. This arrangement ensures a more uniform flow distribution and more effective use of the heat transfer surface. In this context, numerical simulations of the spiral fin integrated shell and helically coiled tube heat exchanger with a new flow channel design has been conducted using the computational fluid dynamics method in ANSYS Fluent software. Numerical analyses showed that the inner tube improves heat transfer by regulating the flow, while the spiral fins distribute the cold fluid homogeneously over the helical tube surface and create turbulence, which significantly enhance heat transfer. To validate these findings, a prototype of the desgined shell and helically coiled tube heat exchanger with a new flow channel design and spiral fins was manufactured and experimented using pure water at various volumetric flow rates. Comparing the experimental findings with the numerical simulation results showed an average difference of 3.9% in the cold fluid outlet temperatures. Overall findings of the study indicated that simultaneous utilization of the inner tube and spiral fins importantly enhanced the thermal efficiency of the shell and helically coiled tube heat exchanger.