Influences of nozzle aspect ratio and inlet Reynolds number on flow and heat transfer characteristics for middle double swirl cooling

In this paper, the middle double swirl cooling (M-DSC) models for diverse nozzle aspect ratios (Car) are estab-lished for flow and heat transfer behavior research. The k-omega turbulence model and the 3D viscous steady RANS equations are utilized for numerical calculation. The finite volume method and coupled implicit solver are chosen for simulation calculation. Influences of Car values, namely 0.375, 0.67, 1.5, 2.67, 4.17 and 6 on the flow characteristics and thermal performance for the M-DSC are investigated when keeping vortex nozzle inlet area constant. Moreover, the cooling performance for diverse inlet Reynolds numbers 12,500, 22,500, 32,500 and 42,500 is studied with the model owning the optimal Car. Results show that the velocity of the crossflow will increase along in the outlet direction. As Car decreases, the velocity where the jet coolant scours the target will decay more significantly toward the outlet. There are four typical shapes of high heat transfer regions on the target. The uniformity of heat transfer will increase with the growth of Car. When the Car is 4.17, the thermal performance factor is the highest. The flow and heat transfer regulations are almost constant when the inlet Reynolds number is altered.