【作者】 焦兵锋；

【导师】 李德胜；

【作者基本信息】 北京工业大学 ， 机械工程， 2014， 博士

【摘要】 随着公路的快速发展和公路质量的提高，使汽车运输在交通运输中所占的比例不断提高。近年来制动失效和制动不良所导致的事故仍在所有交通事故中占有很大比例。对此，国外已强制将缓速器作为汽车的标准配置，而国内目前只在大型客车上普及了电涡流缓速器的安装。由于目前电涡流缓速器和新一代的永磁缓速器均采用风冷散热，其散热效果差，制动力矩热衰退问题严重，结构相对复杂，且永磁缓速器制动力矩小、性价比低，难以满足大型货车对连续制动和大制动力矩的要求。因此研发具有长时间制动能力、制动力矩大、结构简单和成本低廉的新型汽车缓速器对打破国外对汽车缓速器的技术垄断，普及缓速器在重型汽车上的安装，从而提高重型车辆的行车安全，防止因制动失灵产生的交通事故等都具有重要意义。电涡流缓速器和永磁缓速器均通过电场和磁场产生制动力矩，因此统称为电磁缓速器。电磁缓速器的物理现象涉及电场、磁场、热场、流场和应力场等多物理场耦合，目前对电磁缓速器的研究集中于对传统风冷散热的缓速器中各单物理场的研究，很少考虑多场耦合的情况。对电磁缓速器优化设计的研究也相对较少。本论文针对电磁缓速器制动力矩热衰退严重、结构复杂和性价比低等问题，提出了多种新型缓速器。然后进行了大量的多物理场及其耦合分析研究、优化设计研究和试验。论文主要章节和内容包括：第一章综述了汽车缓速器的功能、相关法规、分类和研究意义等。比较了电涡流缓速器和永磁缓速器的特点。详细阐述了两类缓速器的研究现状。最后针对目前存在的问题提出了论文的研究内容和方法。第二章提出了新型双凸极电涡流液冷缓速器制动力矩的多场耦合分析方法。首先提出了其基本结构和工作原理。然后提出了一种计算电涡流缓速器制动力矩的方法。其次建立了缓速器的静磁场分析模型及定子流场-热场耦合分析模型。并说明了将流场-热场-磁场分析和制动力矩计算相耦合的分析过程。最后描述了缓速器的实验方法和过程，并比较了实验结果与计算结果。为新型缓速器的制动力矩计算提供了一种方法，为缓速器的设计和优化提供了理论基础。第三章基于响应面方法优化了新型永磁液冷缓速器的结构。首先提出了新型缓速器的基本结构和工作原理。随后建立了缓速器的瞬态磁场分析模型并计算其制动力矩。然后分别以制造成本（永久磁铁用量）约束下的制动力矩最大为优化目标和制动力矩约束下的制造成本（永久磁铁用量）最少为优化目标，采用响应面方法建立了两个近似优化模型，优化了缓速器的结构参数。为缓速器的优化设计提供了一种有效的新途径。第四章全面分析了永磁液冷缓速器的多物理场特性，并计算了新型转子冷却式永磁液冷缓速器的残余力矩。首先分别建立了永磁液冷缓速器的热场、磁场和应力场等多物理场分析模型，包括：建立了定子热场分析模型，运用传热学理论合理的计算了定子水道的平均表面传热系数等边界条件。在此基础上分析了缓速器在实验条件和车载工作条件下定子的温度分布。然后建立了缓速器永久磁铁热场分析模型，在定子热场分析的基础上，合理的计算了模型的热边界条件，并计算了永久磁铁在实验条件和车载工作条件下的温度分布。接着建立了缓速器的静磁场分析模型。同时建立了缓速器定子的静力分析模型，并根据缓速器的实际工作情况，合理地计算了模型的受力边界条件，分析了定子的应力分布和变形情况。此外，运用传热学理讨论了水道几何尺寸对定子水道散热效率的影响。最后提出了新型转子冷却式永磁液冷缓速器的基本结构和工作原理。并计算了其转子在液冷腔内旋转时所受的阻力大小。为缓速器的设计和优化提供了理论基础。第五章研究了永磁液冷缓速器的流场-热场耦合特性。首先以前人文献中的实验为基础，在单面加热的弯曲管道传热性能的数值模拟中，比较了三种低雷诺数湍流模型SST、SST-CC和BSL SMC模型的特性，探索了这三种模型应用于缓速器稳态流场-热场耦合分析的可行性。然后以缓速器稳态流场-热场耦合分析为基础，了解了冷却液流量、水道入口水温、水道高度和定子热传导区高度对缓速器定子和永久磁铁温度的影响。为定子水道的强化传热研究奠定了基础。第六章分析了新型盘式永磁缓速器和新型盘式永磁液冷测功机的多物理场特性，并优化了盘式永磁缓速器的结构。在介绍了两种缓速器的基本结构和工作原理后，首先建立了盘式永磁缓速器励磁装置的瞬态热场模型，根据盘式永磁缓速器台架实验得到的温度数据，对励磁装置进行了瞬态热场分析，分析中考虑了气隙的热传导和热辐射。然后建立了缓速器的静磁场分析模型，并使用虚功法计算了转子对定子的吸力。在此基础上，采用一阶优化方法优化了缓速器的5个结构参数。最后建立了盘式永磁液冷测功机定子的稳态热场分析模型，使用传热学理论计算了测功机定子中设置的水道的平均表面传热系数。获得了定子的热场分布，并比较了计算结果与实验结果。最后为论文的结论及对未来研究内容的展望。更多还原

【Abstract】 The rapid development of roads and improvement of the quality of roads makethe percentage of vehicle transport increase in transportation. In recent years, the ac-cidents caused by braking failure and braking inefficiency are still accounted for asignificant proportion of all accidents. For that, the retarders are forced to be thestandard equipment for vehicles in abroad, whereas the eddy current retarders arepopularized only in motorbuses in China. Because the heat generated by the eddycurrent retarder (ECR) and new generation permanent magnet retarder (PMR) istransferred by air forced convection, the poor efficiency of heat transfer leads to thesevere fading of braking torque. Moreover, their structures are complicated. Besides,the braking torque of PMR is small, and its cost performance is low. All aspects aboveresult in the lack of satisfaction of the ECR and PMR for the needs of continuousbraking and large braking torque of heavy vehicles. Thus, research and developmentof new types of retarders for heavy vehicles are very important, and their characteris-tics are the ability of braking in continuous working conditions, large braking torque,simple structure and low product costs. It is significant to break the monopoly of re-tarders from abroad, popularize the installing of retarders in heavy vehicles, improvethe safety of heavy vehicles and prevent the travel accidents caused by braking fail-ures.The ECR and PMR generate braking torque by electronic field and magneticfield, so they are collectively called the “electromagnetic retarder”(EMR). There arecoupled fields including the electronic field, magnetic field, thermal field, flow fieldand stress field in the EMR, whereas most researches focus on sigle physical field andlittle on coupled fields. Besides, the researches on optimization of the retarder are lessrelatively.To solve the problems of severe fading of braking torque, complicated structureand low cost performance and so on, many new types of retarders were proposed inthis dissertation. Then a lot of analyses of multi-physical fields and their coupledfields, optimizations and experiments were reported in the dissertation. The mainchapters and contents of the dissertation are: The opening chapter summarized the functions of the retarder for vehicle, relatedlaws and regulations, classification and importance of this research, etc. The charac-teristics of ECR and PMR were compared. The present situations of these two retard-ers were described. Finally, to solve current problems, the contents and methodologiesof the dissertation were proposed.In chatper2, a coupled field analysis method was presented to obtain the brakingtorque of the new type liquid-cooled eddy current retarder with doubly salient polesstructure. Firstly, the basic structure and working principle of the new retarder wereproposed. Then a method to calculate the braking torque was presented. Thirdly, thestatic magnetic analysis model and flow-thermal coupled field analysis model werebuilt. After that, a coupled method of the flow-thermal-magnetic field analysis andbraking torque calculation was presented. Finally, the experiment method and proce-dure were introduced, and the comparision of the braking torque obtained by analysesand tests were carried out. Thus, a way was provided to compute the braking torque ofthe new retarder for further design and optimization.Chapter3was devoted to the optimization of the new type liquid-cooled perma-nent magnetic retarder (PMR-LC) based on the response surface methodology (RSM).At the beginning, the basic structure and working principle of the new retarder werepresented. Next, the transient magnetic analysis model of the retarder was establishedand the braking torque was calculated. Then, respectively, to maximize the brakingtorque (subjected to the product costs) and minimize the product costs (subjected to acertain braking torque demand), two approximating optimization models were builtby the RSM. Finally, the braking torque was increased and the product cost was de-creased under a certain braking torque demand. So, an effective way to optimize thestructure of retarder was proposed.Chapter4gave a thorough understanding of the characteristics of the mul-ti-physical fields in the PMR-LC, and the residual braking torque of a new type of re-tarder named rotor-liquid-cooled permanent magnet retarder (PMR-RLC) was calcu-lated. First of all, the thermal field, the magnetic field and the stress field analysismodels of the PMR-LC were built respectively. Firstly, the thermal field analysismodel of stator was established. The heat transfer theory was used to reasonably cal-culate the mean surface coefficient of heat transfer of the cooling duct and otherboundary conditions. The temperature distributions of the stator under the experiment conditions and working conditions in vehicle were analyzed. Secondly, the thermalfield analysis model of permanent magnet was built. Based on the results of thermalanalysis of the stator, the thermal boundary conditions were calculated reasonably,and the temperature distribution of permanent magnet under the experiment condi-tions and working conditions in vehicles were analyzed. Then, the static magneticfield analysis model of the retarder was established. Fourthly, the static structureanalysis model of the stator was built, and the boundary conditions of forces werecalculated based on the real working conditions. The stress field and displacementwere analyzed. Besides, the influence of geometry parameters of cooling duct on theefficiency of thermal transfer was discussed based on the heat transfer theory. Finally,the basic structure and working principle of the PMR-RLC were proposed. The re-sistance of the rotor in the cavity that is full of liquid was calculated. All analysesprovided the theoretical basis for further design and optimization of the new retarders.Chapter5mainly analyzed the features of the coupled field of the flow field andthermal field in the PMR-LC. Firstly, based on the experiments in a literature, thecharacteristics of three low Reynolds turbulent models named SST, SST-CC and BSLSMC were compared in the numerical simulations of heat transfer of a curved ductheated at outer curved surface. The feasibility of the application of three models in thecoupled analysis of flow-thermal field in the retarder was explored. Then, based onthe analyses of flow-thermal field in the retarder, the influence of rate of flow, thetemperature of liquid at the inlet, the height of duct and the height of conduction zonein the stator on the temperature of the stator and permanent magnet were understood.The research provided the theoretical basis for further design and optimization of heattransfer enhancement of the cooling duct in new retarders.In the final chapter, the performances of multi-physical fields of a new disk typeof permanent magnet retarder (PMR-D) and a new disk type of liquid-cooled perma-nent brake dynamometer (PBD-DLC) were analyzed, and the structure of PMR-D wasoptimized. After the basic structure and working principle of the retarder and dyna-mometer were presented, the transient thermal model of the magnetic equipment inthe retarder was built firstly. According to the thermal data in the tests of the retarder,transient thermal analyses were carried out with the boundary conditions of thermalconduction and thermal radiation. Then, the static magnetic field analysis model ofthe retarder was established，and the suction between the rotor and stator was calcu- lated by virtual work method. Based on the static magnetic field analysis, five param-eters of the retarder were optimized by the first order method. Finally, the static ther-mal analysis model of the brake dynamometer was built. The heat transfer theory wasused to reasonably calculate the mean surface coefficient of heat transfer of the cool-ing duct. The thermal field distribution was obtaioned and compared with the datafrom the experiments.The final part of the dissertation was the conclusion and the expectation of fur-ther researches in the future.更多还原