车辆通风式制动盘内部通道对流换热研究综述

总结了通风式制动盘内部通道对流换热的研究成果，从内部通道的质量流量、对流换热系数和有效散热表面积三方面，分析了不同结构设计对制动盘内部通道换热的影响；从解析法、数值分析法和试验测试法三方面，综述了国内外在对流换热分析和检测方法的研究概况。研究结果表明:在径向叶片制动盘通道内，主要存在2种流动方式，由紧邻叶片吸力侧气流分离引起的回流和在径向通道内部旋转的二次流，抑制回流区的形成可以提高泵送空气质量流量，使通道内的温度分布更加均匀，二次流将促进通道间的空气混合流动和湍流的发展，加强局部剪切应力，改善制动盘散热性能；综合应用射流冲击强化方式(多束流、旋流和多方向射流等)、高孔隙率和类柱状结构优化设计也能够改变流体在通道中的流动状态，这些措施都会使得通道内流体扰动增大，热边界层变薄，壁面附近的速度梯度增大，有效提高了制动盘的对流换热系数，增强了散热能力；采用解析法和数值分析法得到的结果具有很强的理论参考价值，而采用试验测试法所获得的结果更加接近制动盘实际内部温度和气体流速的变化，因此，若能将三者无缝结合，实现优势互补，则最具有科学研究价值；在对高速车辆制动盘结构进行优化设计时，为了获得最大的散热效率，往往忽略了通道内摩擦压降和流动阻力，因此，如何平衡散热与摩擦压降、流动阻力之间的关系，还需进一步深入探索与研究。 

Review on convective heat transfer in internal channel of ventilated brake disc of vehicle

The research results of convective heat transfer in the internal channel of ventilated brake disc were summarized, and the influences of different structural designs on the heat transfer were analyzed from three aspects: mass flow, convective heat transfer coefficient and effective heat dissipation surface area. The analysis and detection methods of the convective heat transfer were reviewed at home and abroad from three aspects: analytical method, numerical analysis method and experimental test method. Research results show that there are two main flow modes in the channel of radial blade brake disc: the backflow caused by the airflow separation adjacent to the suction side of the blade and the secondary flow rotating in the radial channel. Restraining the formation of the backflow zone can increase the mass flow rate of the pumping air and make the temperature distribution in the channel more uniform. The secondary flow promotes the development of air mixed flow and turbulence between the channels, strengthens the local shear stress and improves the heat dissipation performance of the brake disc. In addition, the comprehensive application of jet impingement strengthening methods (multi-beam, swirl and multi-directional jets, etc.), high porosity and columnar-like structure optimization design can also change the flow state of the fluid in the channel. These measures increase the fluid disturbance in the channel, thin the thermal boundary layer and increase the velocity gradient near the wall, which effectively improve the convective heat transfer coefficient of the brake disc and enhance the heat dissipation capacity. The results obtained by the analytical method and numerical analysis method have strong theoretical reference, but the results obtained by the experimental test method are closer to the changes of the actual internal temperature and air flow rate of the brake disc. Therefore, if the three methods can be seamlessly combined to achieve complementary advantages, it will have the most scientific research value. Besides, in order to obtain the maximum heat dissipation efficiency, the friction pressure drop and flow resistance in the channel are often ignored in optimizing the brake disc structure of high-speed vehicle. Therefore, how to balance the relationship among heat dissipation, frictional pressure-drop and flow resistance needs further exploration and research. 3 tabs, 12 figs, 116 refs.