液力缓速器瞬态两相流动大涡模拟及性能预测

为了全面掌握液力缓速器各个流动单元内速度场和压力场的分布特性,提取了全流道几何模型作为计算区域,利用CFD平台的大涡模拟法和多流动区域耦合计算的滑动网格法对液力缓速器内部气液两相流动进行了三维瞬态数值模拟,将混合模型与欧拉模型交替运用在其多相流模型中,获得了不同充液率下液力缓速器内流场结构的变化及两相体积分数分布情况,分析了流场内二次流、脱流及涡旋的产生机理,并计算了缓速器的外特性.结果表明:数值计算结果与试验结果吻合很好,误差在8％以内;流场计算十分准确,运用的大涡模拟方法可以有效地模拟液力缓速器流场内的真实液流结构,其结果可以用来指导液力缓速器的设计及其结构优化.

Large eddy simulation and characteristic prediction of transient two-phase flow for hydraulic retarder

In order to obtain the velocity and pressure distribution characteristics in each flow unit field,the full-flow channel geometry model was extracted as compute domain to conduct the three-dimension transient numerical simulation of gas-liquid two-phase flow in hydraulic retarder based on the large eddy simulation method and sliding mesh theory for multi-flow regions coupled calculation in CFD software.Mixture model and Eulerian model were used alternately to achieve the structure change of internal flow field and the volume distribution of the two-phase flow under different filling rate.The generation mechanism of secondary flow,flow separation and vortex was analyzed,and the external retarder characteristic was also calculated.The results show that the numerical results are in good consistency with experimental data with the error less than 8%.The large eddy simulation method can effectively simulate the true flow structure in hydraulic retarder flow field and conduct retarder design and structural optimization.