【作者】 陈卫军；

【导师】 徐宗俊； 张力；

【作者基本信息】 重庆大学 ， 机械制造及其自动化， 2008， 硕士

【摘要】 Power MEMS（MEMS-based power sources）即基于MEMS的微能源动力系统,在航空航天、通信、生物医学、国防等领域具有广阔的应用前景,将给现代社会带来重大而深远的影响。国内外已经相继开展了对它的研究,不少概念样机也已经问世,不过究其实质大多都是将现有宏观尺度的热机进行比例微缩（Scale Down）所形成的中介尺度热机概念。虽然其工作过程与宏观尺度相同,但是在结构的微型化过程中形成的几何相似,却难以确保机械相似和热力相似的成立,这直接导致了到目前为止尚没有出现成功的超高能量密度Power MEMS实例样机,也极大地限制了国际上Power MEMS研究的发展。本论文在此基础上探索性地提出了超高能量密度Power MEMS准气体动力循环（Quasi Gas Power Cycle）的理论观点,并对采用该循环的Power MEMS微型发动机进行了原理性设计及分析,同时以管道式和环形微燃烧器为例,利用化学动力学软件CHEMKIN模拟了微空间氢氧燃烧过程,最后还进行了实验样机、实验台架的研制以及相关实验研究。首先,本文详细介绍了Power MEMS准气体动力循环（Quasi Gas Power Cycle）的原理,并在此基础上对Power MEMS准气体动力循环微型发动机进行了原理性设计,包括概念设计和相应结构设计。与此同时,还对所设计的发动机进行了简单的动力学分析和热力学分析。分析发现,在转速为5000rpm的情况下,所设计的外径为43mm的样机强度是满足要求的;而且随着进气压力的升高,发动机的热效率和输出功率也随之增大。其次,本文通过对H₂/air及H₂/O₂混合燃气在微管道型及Power MEMS环形燃烧室中燃烧的情况进行数值模拟,关注反应压力、当量比以及催化介质等对燃烧室内温度的分布及变化、各组分在燃烧室内的分布及其变化、化学反应的速率的影响。模拟结果表明:在微管道燃烧器中,较高的反应压力有利于提高微燃烧器氢氧燃烧效率,但过高的反应压力却会限制微燃烧器的燃烧负荷率;选择合适的当量比（1～1.5）有利于微燃烧器氢氧混合物的充分燃烧;催化燃烧需要一个最低的热通量或温度来完成点火。而在环形燃烧室中,反应压力的影响与微管道燃烧室类似,且由于尺度效应的影响,其点火也需要催化媒介或外界热量的传递才能完成。最后,本文介绍了Power MEMS准气体动力循环发动机样机的试制及其实验研究,着重对样机的制造过程、微型化实验台架的设计和原理以及所进行的测功实验进行了阐述。实验样机倒拖实验中的试运转成功证明了其机械结构的可行性;由于各方面原因,样机最高转速只停留在2000r/min左右,但在所测转速范围内样机的输出功率随着其转速的增大而增大,最大功率为16W左右。更多还原

【Abstract】 Power MEMS is micro electromechanical system based power sources, which has extensive prospect in fields of airspace, communication, biomedicine, national defense and so on, and which will bring profound significance to the society. At present, there are many investigates into Power MEMS and many conceptual model machines have been manufactured. However, most of them were essentially generated by scaling the corresponding macro heat engines down to meso scale. The thermodynamic processes of these micro-scaled heat engines are totally the same as that of those corresponding macro engines but the geometrical similarity generated in the process of scaling down can hardly ensure the accuracy of the mechanical similarity and the thermal similarity, which results in no appearance of successful Power MEMS model machine with ultra-high power density and extremely restricts the development of international Power MEMS research.Based on this, the theory of quasi gas power cycle with ultra-high power density for Power MEMS is proposed exploringly in this paper. The theoretical design and analyze of Power MEMS micro engine, which adopts this cycle, are also carried out. Meanwhile, taking micro pipeline and annular combustor as example, the chemical reaction dynamic soft CHEMKIN is applied to simulate the micro-combustion of hydrogen-oxygen mixture. Finally, the design and manufacturing of a prototype and its test-rig is performed, together with corresponding experimental research.Firstly, the principle of quasi gas power cycle for Power MEMS is detailedly presented in this paper. And based on this, the theoretical design of micro engine with quasi gas power cycle for Power MEMS is discussed, including conceptual design and corresponding structural design. Meanwhile, simple dynamic analysis and thermodynamic analysis of the engine designed are also performed. The results indicate that the strength of the prototype whose outer diameter is 43mm meets the challenge with a speed of 5000rpm and the thermal efficiency and the engine output tend upwards as the increase of premix gas pressure.Secondly, the micro-combustion of H₂/air and H₂/O₂ mixture in the line type and the Power MEMS annular micro-scaled combustor is simulated and the impact of pressure, equivalence ratio and catalytic agent on chemical reaction rate, the distribution and variation of gas temperature and component in the combustion chamber is emphasized. The result indicates that in the micro pipeline combustor, higher pressure is good for increasing the combustion efficiency of micro combustor while too high pressure will limit the specific combustion intensity; the burning of H2/O2 will be more sufficient if a proper equivalence ratio is chosen; the catalytic combustion needs a smaller heat flux or temperature to complete ignition. However, the impact of pressure on annular combustor is similar to that on pipeline combustor. And its ignition also needs catalysis or outside heat because of the scale effect.Finally, the trial manufacture and experimental research of the prototype of quasi gas power cycle for Power MEMS is performed, which focuses on the manufacturing process of the prototype, the designing of the micro test-rig and the dynamometric test. The successful test-running of the prototype in reverse-drag test proves the feasibility of the mechanical structure but for some reasons, the max speed of the prototype stays only around 2000r/min. However, within the range of speed tested, the output power of the prototype increases along with its speed and the max output power is 16W.更多还原