液力减速器充液过程瞬态特性三维数值模拟

Numerical Investigation on Transient Oil-filling Process of Hydraulic Retarder

为得到紧急充液过程中的液力减速器瞬态内流场特性及制动外特性,基于瞬态流场计算方法建立了某型液力减速器相应的仿真模型。结合实际车用工况确定了入、出油口的流速,设置了精确的初始流场作为边界和初始条件,运用CFD技术对液力减速器紧急制动工况的充液过程进行流场分析及制动外特性仿真计算。以动轮初始转速2 640 r/min紧急充液过程为例分析了液力减速器流道内腔速度、总压、湍流动能分布特点,并对制动外特性仿真结果与试验数据进行了对比,仿真误差为12.7%。表明仿真模型和方法较为合理、准确,瞬态流场仿真方法能更全面地反映液力减速器充液过程中随时间变化的流场内特性及制动外特性。

With the aim to obtain the time-varying braking performance of emergency oil-filling process of hydraulic retarder,a numerical simulation model of flow channel was established based on transient CFD method.The inlet velocity,outlet velocity and a steady flow field result were calculated and applied as the boundary condition and initial condition.Then the transient simulation of emergency oil-filling process was calculated when the initial rotor rotating speed was 2 640 r/min.The pressure,the velocity and the turbulence kinetic energy distribution of internal flow field under different braking time were studied,and the time-varying braking torque was calculated by CFD post-processing analysis.Comparison of the experimental data and simulation results showed that the calculation tolerance of the braking torque was 12.7%.It is indicated that the simulation method and model are accurate and reliable,and the transient simulation method is more appropriate to predict the time-varying braking performance of hydraulic retarder.