组合式射流冲击冷却壁面稳态传热特性仿真分析

射流冲击是一种具有较高的局部换热效率的换热方式,具有重要的工程应用价值.以流体仿真软件Fluent为工具,设计了多个喷嘴组合式的射流冲击冷却模型,研究了组合式射流垂直和倾斜冲击壁面时的稳态传热过程,讨论了喷嘴倾角和间距对壁面传热特性的影响.发现随着斜喷嘴倾角增大,组合式射流的壁面平均努塞尔数先逐渐增大然后减小;组合式射流继承了单束直射流和斜射流的优点,在保证滞止区传热效率较高的同时,有效地提高了射流下游的传热效率并使壁温分布更加均匀;当斜喷嘴靠近直喷嘴时,组合式射流整体传热特性与单束斜射流相似;当沿横向和纵向增大斜喷嘴与直喷嘴间距时,壁面平均努塞尔数均增大.

Simulation analysis of steady-state heat transfer characteristics of combined jet impingement cooling on the wall

Jet impingement is a heat exchange method with high local heat exchange efficiency, and it is very important for engineering application. In this study, by means of fluid simulation software Fluent, a jet impingement cooling model with multiple nozzles was designed, the steady-state heat transfer characteristics of the process was studied when the combined jet impinges on the wall surface vertically and obliquely, and the influence of nozzle inclination angle and distance on the heat transfer characteristics of the wall was discussed. It is found that as the inclination angle of the oblique nozzle increases, the average Nusselt number of the combined jet gradually increases and then decreases. The combined jet inherits the advantages of the single straight jet and the oblique jet. It ensures heat transfer efficiency in the stagnation zone, improves the heat transfer efficiency downstream of the jet effectively and makes the wall temperature distribution more uniform in the meantime. When the oblique nozzle is close to the straight nozzle, the overall heat transfer characteristics of the combined jet are similar to that of the single oblique jet. When the distance between the inclined nozzle and the straight one is increased along the horizontal direction and the longitudinal direction, the average Nusselt number of the wall increases, the two high-temperature regions upstream from the nozzle area shift to the downstream, and the cooling efficiency improves significantly.