液黏离合器摩擦副对流换热系数数值模拟研究

为了预测液黏离合器的温度场分布及热负荷特性，通过数值模拟研究求得摩擦副散热面的对流换热系数。应用计算流体动力学软件CFX建立了摩擦副流固耦合有限元模型，获得了摩擦副的温度场分布，综合考虑换热表面形状、摩擦片转速、油液流速和入口压力、流体物理性质等因素，揭示了各因素与对流换热系数之间的内在联系。结果表明：摩擦副温度从内径到外径逐渐升高，菱形区域中心温度比四周高。摩擦片转速越大对流换热系数越大；油液黏度越小，入口压力越大，对流换热系数越大。可见，油液流速对换热系数的影响最为显著；摩擦片转速、油液的入口压力和黏度会改变流速及流体的运动状态，从而影响对流换热系数。

Numerical Simulation on Convective Heat Transfer Coefficients of Friction Pairs of Hydro-viscous Clutch

In order to predict the temperature field distribution and thermal load characteristics of the hydro-viscous clutch, the convective heat transfer coefficient of the heat dissipation surface of the friction pairs was obtained by numerical simulation. The fluid-solid coupling finite element model of the friction pairs was established by using CFX, then the temperature field distribution of the friction pairs was obtained. The internal relationship between the factors and the convective heat transfer coefficient was revealed by taking the shape of the heat exchange surface, the speed of the friction disk, the velocity of oil and inlet pressure, and the physical properties of the fluid into consideration. The results showed that the temperature of friction pairs increased gradually from the inner diameter to the outer diameter, and the center temperature of rhombus area was higher than that of the surrounding area. The greater the rotating speed of the friction disk, the greater the convective heat transfer coefficient; the smaller the oil viscosity, the greater the inlet pressure and the greater the convective heat transfer coefficient. It can be seen that the effect of oil velocity on the heat transfer coefficient was most significant. The rotating speed of friction disk, inlet pressure and viscosity of oil could change the flow velocity and condition, thus affecting the convection heat transfer coefficient.