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在考虑发动机冷却通道固壁内耦合导热影响的情况下,开展了低温甲烷在矩形冷却通道中的超临界压力湍流换热数值模拟研究;仔细分析了热流密度及管道几何形状对低温甲烷超临界压力下的流动和传热的影响;得到了流体速度、壁面温度、壁面热流密度等参数的详细变化情况以及Nusselt数的变化规律。计算结果表明:在考虑流固耦合作用时,上壁面施加的热流有一部分会通过固体壁面内的热传导,经由侧壁面传入超临界压力流体,并且随着热流密度的增加,经侧壁面传导的热流所占的比例也会随之增大;减小冷却通道内截面的高宽比,可以提高超临界压力下的换热效果,但流动压降会大大增加,因此冷却通道高宽比的选择需综合考虑传热与压力损失的影响,可以引入热性能参数作为参考;修正的Jackson&Hall对流换热关系式基本可以适用于本文中的各种工况。
The numerical simulation of the supercritical pressure turbulent heat transfer in a rectangular cooling channel was carried out under the influence of the coupling thermal conductivity in the solid wall of the engine cooling channel. The effects of heat flux density and pipe geometry on the supercritical pressure Under the influence of the flow and heat transfer, the detailed changes of fluid velocity, wall temperature, wall heat flux and other parameters and the variation regularity of Nusselt number were obtained. The calculation results show that when the fluid-structure interaction is considered, some of the heat flux applied by the upper wall passes into the supercritical pressure fluid through the side wall through the heat conduction in the solid wall, and as the heat flux increases, the heat conduction through the side wall The proportion of heat flow will also increase; reducing the aspect ratio of the cross-section of the cooling channel can improve the heat transfer effect under supercritical pressure, but the flow pressure drop will greatly increase, so the choice of aspect ratio Considering the effects of heat transfer and pressure loss, the thermal performance parameters can be used as a reference. The modified Jackson & Hall convective heat transfer equation can basically be applied to the various working conditions in this paper.