高速列车关键热物理基础问题研究

The fundamental thermal physical problems related to the high-speed trains determine the capacity of heat exchangers used in the trains, the friction loss of the trains, the brake power and the brake reliability of the trains, the life-span of the wheel and the track, and the trains' dynamics behaves connected with condition of the wheel and the truck. After carefully analyzing, this project firstly screens out the fundamental thermal physical problems for the high-speed trains especially. These fundamental problems include: the fluid flow and heat transfer characteristics of week jets and suctions through array of the slots moving at high speed; the characteristics of the main flow when it passes over and moves downstream the array; the fluid flow and heat transfer characteristics of the high-speed rolling wheel or pads and their heat transfer mechanism; the transport mechanism of the heat produced by wearing of the wheel and the track. These fundamental problems are interdisciplinary problems interacted with air dynamics, solid mechanics, material science, and tribology. Equipped with theoretical analysis, numerical and experimental methods, from the view point of interdisciplinary of many related fields, this project starts from investigation of heat transfer phenomenon, also focuses the phenomenon related to other fields, and tries to study the fundamental thermal physical problems systematically and thoroughly. The main contents of this study are: (1) fluid flow and heat transfer characteristics of week jets and suctions through the array of the slots moving at high speed, the interaction characteristics of such flow with the outer flow field, it is expected that the results will be very useful for designing heat transfer equipments and ventilating equipments used in high-speed trains, and getting insights of air dynamics produced by the array of moving slots; (2) fluid flow and heat transfer characteristics in the boundary layer formed by the high-speed rolling wheel or pads, and their heat transfer mechanism, the results will be useful for designing the efficient breaking system, to make sure the safety of the high-speed trains; (3) using the interdisciplinary model, the transport mechanism of the heat produced by wearing of the wheel and the track will be studied, the results will be used to develop the very efficient technologies to improve the life span of the wheel and the track, which is the key issue to decrease the running cost of high-speed trains. The results of this project are very important not only to enrich the knowledge of traditional engineering thermal sciences, but also to form a new research field interacted with related fields. The results will form the theoretical base to design key parts of high-speed trains, to improve the life-span of the wheel and the track, to decrease running cost of high-speed trains, and to increase the safety of the trains.

高速列车由于高速所引起的流动传热问题直接决定着列车的热端部件散热特性、制动能力、安全可靠性、轮轨寿命及与之相关的动力特性，是提升列车运行安全可靠性及降低能耗和成本的关键，成为自主设计核心部件的基础理论问题，涉及外掠阵列缝隙弱抽吸/弱射流流动及阵列内部流动与传热、移动面限制滚动类部件所引起的流动传热、轮轨摩擦热传递等热物理现象，与空气动力学、固体力学、摩擦学和材料学形成复杂交叉。在常规传热学对这些现象很少研究的现状下，项目从学科交叉角度出发，以揭示传热现象为切入点，关注学科交叉现象，采用实验、数值模拟和理论分析研究方法，拟开展：（1）高速移动阵列缝隙弱抽吸/弱射流流动传热及外部流场特性；（2）高速滚动部件边界层结构及对流传热机理；（3）基于流/固体力学、材料学、传热学和摩擦学耦合模型的摩擦热传输机理等研究。项目结果将丰富和发展传热学的研究领域，并为高速列车核心部件的设计提供坚实的理论基础。

高速列车由于高速所引起的热物理问题直接决定着列车关键部件散热特性、制动能力、安全可靠性、轮轨寿命及与之相关的动力特性，是提升列车运行安全可靠性及降低能耗和成本的关键，成为设计核心部件的基础理论问题。涉及高速列车与大气的热质交换、摩擦热传递、外掠阵列缝隙弱抽吸/弱射流流动等热物理现象，与流体学、固体力学、摩擦学和材料学形成复杂学科交叉。在这些问题鲜见报道的背景下，项目从学科交叉角度出发，以揭示传热现象为切入点，关注学科交叉热物理现象，采用实验、数值模拟和理论分析研究方法，开展了：高速滚动部件对流传热机理；基于流/固体力学、材料学、传热学和摩擦学耦合模型的摩擦热传输机理；高速移动阵列缝隙弱抽吸/弱射流流动流场特性等研究。. 研究获得了：滚动车轮表面传热特性关联式；列车通过时钢轨表面传热特性关联式；制动盘表面传热特性关联式；一典型制动盘内部通道传热特性关联式；测量轮/轨瞬间非稳态对流传热特性测试方法及瞬态传热特性；轮轨摩擦副摩擦系数与温度关系；单一金相组织组摩擦副摩擦系数；影响摩擦热大小及传输的关键参数；摩擦系数、摩擦热对轮轨关系、摩擦学、固体力学特性的影响规律；阵列缝隙弱射流、弱抽吸流动特性和主流速度的关系；外掠阵列缝隙弱抽吸、弱射流的流动特性；建成了测量阵列缝隙弱射流、弱抽吸流动特性实验平台；建立阵列缝隙弱射流、弱抽吸流动模型及计算程序；建立摩擦副摩擦热传输的流/固体力学、传热学、摩擦学耦合模型。. 研究结果揭示了：移动面限制滚动类部件表面、轮轨接触斑附近表面流动结构及对流换热特性；制动摩擦副、轮轨摩擦副摩擦热传输机理；摩擦热对摩擦副摩擦系数、磨损、强度、疲劳的作用机制；外掠有限阵列缝隙弱抽吸、弱射流流动结构及边界层特征；高速移动有限阵列缝隙弱抽吸、弱射流本身的流动结构。研究结果丰富和发展了相关学科知识，并为高速列车核心部件的设计奠定了坚实的理论基础。