液力减速器制动性能及其两相流分析方法研究

Study on Braking Performance and Analysis of Two-Phase Flow in Vehicular Hydraulic Retarder

摘要: 为对车用液力减速器在制动过程中制动性能进行准确预测,在全充液的单一液相流动到不充液的单一气相流动的整个工作过程中,对于无内环的液力元件采用混合入、出口的边界条件处理方法,对充液率分别为100%、80%、60%、40%及20%时的工况分别进行CFD液力减速器内流场数值模拟,获取不同充液率和不同转速下的制动性能曲线,并得到对应不同工况的速度和压力场分布特性. 结果表明,CFD数值模拟可以较为准确地预测制动性能,并且混合入、出口的边界条件处理方法更符合无内环叶轮机械内部的实际流动本质.

Abstract: To accurately predict brake performance of vehicular hydraulic retarder during brake process, in the working procedure from liquid phase to gas phase, the working condition with different liquid-filled ratios of 100%, 80%, 60%, 40% and 20% were numerically simulated by imposing reasonable boundary condition of mixing flow passage inlet and outlet. The brake performance curves and power loss curve of different liquid-filled ratios and rotating speeds were obtained. Result of simulation shows that the CFD numerical simulation model can accurately predict brake performance and the boundary condition of mixing flow passage inlet and outlet agrees well with the nature of practical flow in fluid mechanism without hub.