液力缓速器动态制动过程特性预测方法

Simulation method for dynamic braking process of hydrodynamic retarders

为解决传统单纯设定己知缓速器动轮转速的仿真方法不能预测在瞬态制动过程中的转速变化及其相应流动特性问题,通过将整车惯量施加到动轮上,根据当前时刻流场压力分布积分所得的转矩计算角加速度,从而确定下一时刻的转速,将其作为流场仿真的转速输入.利用这种流场-转速耦合特性预测方法,对缓速器整个动态减速制动过程的内部流动行为进行动态仿真预测.仿真结果与试验数据对比表明:该方法对于模拟转速被动变化的动态制动过程具有较好的准确性,能够预测缓速器在自身流场和整车惯量的共同相互作用下,动轮的转速及制动转矩的变化规律.

The retarder rotor speed is not only the input parameter of retarder,but also the result of braking torque and vehicle inertia,and traditional CFD method which demands a given speed can not simulate the change of rotor speed and consequent flow field accurately.Aiming at this problem,flow-rotation coupled method was applied to embody the inertia of the whole vehicle on the rotor and angular acceleration was determined by this inertia and torque generated from the flow field.In this way,the behavior of speed can be determined and used as the input for simulation of the whole dynamic braking procedure.Comparison of the simulation results and experimental data proves that the method is of good accuracy and can be used to predict the change of rotor speed and brake torque under the interaction of internal flow and inertia of the vehicle.