Numerical study on the influence of flow direction and fluid type on heat transfer and pressure drop in a two-tube spiral heat exchanger with innovative conical turbulators

In this research, numerical analysis will be conducted on the thermal and hydraulic performance of a spiral two-tube heat exchanger. The study employs an innovative turbulator design with curved outer blades and a semi-conical section with two openings. Numerical simulations were conducted using the commercialized Finite Volume Method (FVM) program, ANSYS FLUENT 18.2. The finite volume method was employed to analyze thermal and fluid equations and parameters. A comparison was made between two distinct flow directions, namely positive and negative currents, utilizing a comprehensive range of three working fluids. The numerical findings indicate that employing counter-current flow with a Water/MOS2−Fe3O4 fluid nanohybrid results in superior endothermic performance. These results indicate that a maximum thermal efficiency improvement of roughly 17.54 % and 8 % can be achieved by using the counterflow configuration with the nanohybrid fluid Water/MOS2−Fe3O4 at a mass flow rate of m˙ = 0.008 kg/s, in comparison to alternative models. Furthermore, the results showed that the Water/MOS2−Fe3O4 fluid nanohybrid performs better than the Ag-HEG/Water nanohybrid fluid when used in counterflow and parallel flow configurations, starting at a Reynolds number of 600. With a counterflow configuration in the two tubes, the Water/MOS2−Fe3O4fluid nanohybrid achieves the highest thermal performance coefficient in the two-tube heat exchanger.