滚动轮表面对流换热实验研究-热能工程专业论文.docxVIP

兰州交通 兰州交通大学硕士学位论文 滚动轮表 滚动轮表面对流换热实验研究 万方数据 万方数据 万方数据 万方数据 摘 要 近年来，高速列车与重载列车在我国的发展如火如荼，列车在运行以及频繁制动的 过程中摩擦热凸显，摩擦热的作用效果不断延伸到影响列车的运行安全性及运行成本。 作为考虑摩擦热在车轮中传输的关键基础数据，车轮表面传热系数，决定着摩擦热传输 的规律，进而影响着对提高列车运行安全性及降低成本措施的决策。鉴于此理由，本文 将列车车轮抽象为滚动轮，在特殊设计的实验系统中对滚动轮表面的对流传热特性进行 实验研究。 论文的研究内容包括：各种直径滚轮设计；用萘升华传热传质比拟技术获得滚动轮 表面的局部及平均对流传质特性，根据传质/传热比拟关系获得局部及平均传热特性；研 究决定滚动轮传热特性的特征尺寸确定方法。 研究结果表明：(1) 滚动轮、滚动轮表面以及滚动轮踏面的局部努赛尔数与平均努 赛尔数均随着旋转雷诺数的增大而增大；(2) 滚动轮转速相同的情况下，滚动轮以及滚 动轮表面的局部努赛尔数沿着半径增大的方向呈递减的趋势；(3) 滚轮转速相同的情况 下，滚动轮踏面的局部努赛尔数沿着厚度方向的变化趋势为：先降低，随后基本保持不 变，最后又增大；(4) 与旋转圆盘的对流传热特性相比，滚动轮的传热特性明显要低； (5) 获得了决定滚动轮传热特性的特征长度，并得到了此特征长度下的实验无量纲关联 式，为实验数据的扩展应用提供了依据。 关键词：滚动轮；萘升华；对流换热；特征长度 论文类型：应用基础研究 I - Abstract In recent years, the development of high-speed train and heavy-duty train in our country is fast. Friction heat produced when trains move and in train braking process. The effect of friction heat is extended to the safety and cost of train running. As the base data of friction heat transfer in the wheel, heat transfer coefficient decides the friction heat transfer process. The coefficient directly affects the reliability and safety of the train. Due to the influence of heat transfer, the present study the train wheels are modeled by the rolling wheels. The convection heat transfer characteristics of the rolling wheels are studied in special experimental system. The contents of present experimental study include: design rolling wheel with different diameter; obtain the local and average convection mass transfer characteristics on the rolling wheel surface by using naphthalene sublimation technology; get local and average heat transfer characteristics according to the mass/heat transfer analogy relationship; find a method to obtain characteristic length which determine the heat/mass transfer of the rolling wheel. The following conclusions can be drawn: (1) the local and average Nusselt number of the rolling wheel (surface and tread) increases with increasing rotating Reynolds number; (2) under the same rotating Rey