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为了给后续优化陷窝设计提供参考,本文采用RANS数值模拟了底板布置典型深宽比为0.2的陷窝的两组光滑平板间充分发展对流换热流动的情况,分析了陷窝强化对流换热的机理。为验证数值模拟方法的可靠性,建立了与已有文献中的实验一致的模型,与实验结果对比,数值结果误差小于6%,验证了本文数值模拟方法的可靠性。本文通过此数值模拟方法研究表明:陷窝背风面动量输入小、流速低、对流换热弱、类龙卷风涡对壁面螺旋型焦点处对流换热最多减弱50%;陷窝尖后缘的高速绕流、冲击、边界层不连续发展和湍流强度增强等强化了对流换热;陷窝后缘处对流换热最大增强25%;尾流诱导达两倍陷窝表面直径距离的纵向涡对,由于纵向涡对在对称面上诱导向上的速度,对流换热减弱;由于纵向涡对两侧诱导向下的速度,对流换热较强;尾流区换热增强5%~25%。从整体来看,陷窝强化了对流换热。
In order to provide references for the subsequent optimization of lacustrine design, this paper uses RANS numerical simulation to fully develop the convective heat transfer flow between two smooth plates with a typical depth-to-width ratio of 0.2 in the bottom plate. The effects of convective heat transfer The mechanism. In order to verify the reliability of the numerical simulation method, a model consistent with the existing experiments was established. Compared with the experimental results, the error of the numerical results is less than 6%, which verifies the reliability of the numerical simulation method. The results of numerical simulation show that the momentum input of the leeward of the dimples is small, the flow velocity is low and the convective heat transfer is weak. The convective heat transfer of the tornado-like vortex at the focal point of the wall helix decreases by up to 50% Convective heat transfer is intensified by flow, shock, discontinuous development of the boundary layer and enhancement of turbulence intensity. Convection heat transfer increases up to 25% at the trailing edge of the dimple. Longitudinal vortex pairs that up to twice the diameter of the dimple surface are induced by the wake, Longitudinal vortex pairs induce upward velocity on the symmetry plane, and the convective heat transfer is weakened. Because the longitudinal vortex induces downward velocity on both sides, the convective heat transfer is stronger; the heat exchange in the wake area is enhanced by 5% -25%. On the whole, the dimples strengthen the convective heat transfer.