【作者】 蔡贺；

【导师】 徐宇工；

【作者基本信息】 北京交通大学 ， 动力机械工程， 2011， 硕士

【摘要】 随着我国国民经济的发展和国防建设的需要,对轻型飞机的需求越来越大,对轻型飞机发动机的技术和性能要求也越来越高。车用发动机经过长期的发展和不断创新,其冷却系统尤其是换热器技术已经基本完善成熟,但航空发动机不同于车用发动机,其主要在高空运行,高空工况的复杂性和恶劣性是车用发动机无法比拟的。航空发动机换热器作为冷却传热的重要设备,在恶劣条件下,其散热性能的好坏直接影响发动机的散热效果及其动力性、经济性和可靠性,所以对航空发动机换热器的研究日益得到重视。目前航空发动机换热器主要有管片式和管带式两种,所采用的换热方式也是传统的风冷和水冷。在高空进行风冷换热受到气压低,换热量小的制约,水冷又会带来质量的增加。考虑到热管和热管散热技术的特点,将热管应用于航空发动机换热器进行辐射换热不失为一种有意义的探索。本文根据传热学理论,通过对热管换热器设计计算方法的归纳与总结,在增加辐射换热计算方法后,运用VB语言编制了热管辐射式换热器的设计计算程序,实现了热管辐射式换热器的程序化设计。本文针对航空发动机换热器设计要求,以及无人机的性能参数,首先分析了热管工作液体和管壳材料的选择,然后利用热管换热器设计计算程序分析了包括换热面积、肋片参数、热管间距、等效热沉温度、冷却水温度、飞行速度等在内的多种内外参数对热管式换热器性能的影响,根据飞机运行的起飞工况和续航工况以及换热肋面的换热特点,通过模拟无人机运行的极限条件,最终给出本文所探索的热管辐射式换热器在匹配发动机换热器工作要求条件下的换热面积以及不同工况下换热面积的调节策略和较为合理的肋片结构参数与布置方式。更多还原

【Abstract】 With the development of nation economy and the increasing needs of national defense, the demand for both high quantity of light aircraft and high quality of its technology and capability is increasing. The cooling system, especially the heat exchanger of engine used in vehicle has being improved and perfected, with the long time development and continuous innovation. Different from vehicle engines, aeroengine is required of ability to deal with complex and harsh situation in high altitude, which is uncomparible unparallel by engines of vehicle. As an important equipment of cooling and heat transfer, the stability of heat exchanger will directly affect the cooling capacity of aeroengine, and its mobility, efficiency and viability. As a result, research and development of aeroengine attracts increasing attention.At present, there are two catagories of heat exchanger of engine, fin-tube and strip-tube. And there are two traditional ways of heat exchanging, air-cooling and water-cooling. In high altitude, air-cooling method is constrained by low air pressure and small capacity of heat exchange, however water-cooling increases mass. Concerning the characteristic of heat pipe and its heat radiation technology, it is a significant exploration to apply heat pipe to heat exchanger of aeroengine and to use method of radiational heat exchange.In this paper, based on theory of heat transfer and the research of heat pipe exchanger design, with calculation of raidational heat exchange, by using VB language to formulate calculation procecures of design of radiational heat pipe, we realize programmed design of raidational heat exchanger.According to the design requirement of aeroengine’s heat exchanger, and performance parameter of unmanned aerial vehicle, this article analyzes the heat pipe working fluid and the choice of material, and utilizes calculation program of heat pipe exchanger to ananlyse the influence of heat transfer area, fin parameters, heat pipe spacing, space temperature, cooling water temperature, flight speed. Based on condition of takeoff and endurance of aeroplane, and heat exchanging charisteristics of fin surface, through a unmanned aerial vehicle operation in the extreme conditions, this article finally finds out area of heat exchanging, its adjust strategy under different condition, reasonable parameters of fin surface structure, and also the way of settlement.更多还原