Three-dimensional simulation of impingement jet flow and heat transfer with various working fluids

The working fluid plays an important role in the flow and heat transfer performance of impingement jet. Though a lot of fluids such as air, water and oil, have been widely used in jet applications, there lack research works focus on the impacts of fluid properties on the overall heat transfer performance. This paper made comprehensive comparisons of five jet fluids (air, helium, water, FC-77 and MIL-7808) with different thermal properties. The Prandtl number in the present investigation covered a range of 0.67∼342.5. The thermal performance of these fluids were tested by using a three-dimensional impingement jet model. Firstly, this computational fluid dynamics (CFD) model was validated by comparing the simulation results with previous experimental data. The variation of local Nusselt number was interpreted based on the numerical results. Then Nusselt number obtained from different jet fluids were presented in detail. Results indicated that the Nusselt number is strongly dependent on the fluid Prandtl number. Finally, the cooling performance of these fluids was evaluated basing on the present jet configuration. The advantages and disadvantages of these working fluids were discussed from the practical application viewpoint. In particular, we suggest that the helium-jet scheme with the merits of high heat transfer efficiency and high practicality is worth spreading.