| Summary: | 碩士 === 華梵大學 === 機電工程研究所 === 89 === Impinging jets have numerous industrial applications including, among others, the annealing of impellers, glass or metals and the cooling of electronic components. In this thesis, the thermal-fluid characteristics of a three-dimensional impinging jet array are simulated numerically by using CFX 4.2. The low Reynolds number turbulent model is adopted, and the finite volume method is used to solve the Navier-Stodes equations. The distributions of velocity, temperature, pressure, wall heat flux, shear stress and Nusselt number are figured out. The effects of the inlet flow velocity, the distance between the impinging holes and the confining surface, and the direction of exit fluid on the distributions of these physical quantities are investigated.
In this study, it is found that the heat transfer is higher if the flow enters and exits in the same direction than that if the flow enters and exits in the opposite direction. If the distance between the impinging holes and the confining surface is smaller, then the shift in impingement location on the confining surface is smaller and the pressure on the confining surface is higher. The effects of the crossflow are most significant for the impinging holes on the symmetric plane. The effects of the crossflow are less significant when the inlet flow velocity increases.
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