This study examines the performance and heat transfer of helical tube heat exchangers using both experiments and simulations. Four tube configurations were tested: fixed diameter, variable diameter, variable pitch, and a combined configuration. A 2D model was used for the simulations, and the results were analyzed in ANSYS Fluent to determine factors like the coefficient of performance (COP), velocity, and temperature distribution for each configuration. These results were compared with experimental data from a conventional helical coil of fixed diameter. The numerical results were found to be reliable, with small differences from the experiments. The study shows that the new helical coil designs improve heat transfer, with the best performance coming from a helical coil with a conical shape and variable pitch. Overall, this work provides useful insights for improving helical tube designs in engineering applications.
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