簧片阀式脉冲爆震发动机研究

发布时间：2017-12-27 01:28

本文关键词：簧片阀式脉冲爆震发动机研究　出处：《南京理工大学》2015年博士论文　论文类型：学位论文

【摘要】：脉冲爆震发动机(Pulse Detonation Engine,简称PDE)具有热循环效率高、结构简单、飞行马赫数宽、自增压等优点,在未来推进领域具有广阔应用前景,近年来得到了世界各国的广泛关注。鉴于目前PDE研究存在的问题,通过实验和数值模拟,开展了簧片阀式脉冲爆震发动机研究。以汽油为介质,采用PIV和Shadowgraph技术研究不同喷射压力下旋流喷嘴的雾化特征。结果表明：喷雾场核心区的索太尔平均直径明显小于喷雾场外侧区域；当喷射压力增加时,喷雾核心区速度增加,外侧速度减小,喷雾速度场的锥形特征逐渐消失,喷雾场的平均涡量增加；提出了基于速度加权的涡量判定准则,获得了不同喷射压力下喷雾诱导涡结构的运动规律以及无量纲涡平移速度随无量纲时间的变化规律；提出了燃料-氧化剂掺混度和PDE循环工作稳定性的评价指标；分析了燃料雾化、混合对PDE工作稳定性的影响,研究表明：簧片阀对改善燃料分布和掺混度具有积极作用,簧片阀式PDE获得了较好的工作稳定性；当掺混度低于0.72时,PDE循环工作稳定性随掺混度的降低而迅速降低；当掺混度大于0.72时,提高掺混度对改善PDE工作稳定性的影响较小；与掺混度相比,液滴平均粒径对PDEI作稳定性的影响较小,但对爆震波速度影响较大。采用离子探针和压力传感器对火焰和压力信号进行同步测量,分析爆燃向爆震转变(Deflagration to Detonation Transition,简称DDT)过程。结果表明：推力壁反向堵塞比不影响DDT过程的本质规律,但影响DDT距离；由于簧片阀具有较好的反向密封性,簧片阀式PDE获得了较短的DDT距离；随着索太尔平均直径的增大,喷雾爆震的诱导时间和诱导区长度均增加,其中诱导时间的增加幅度大于诱导区长度的增加幅度。基于比热比和气体常数的合理假设,建立了变比热比和变气体常数的单步反应模型；明确了化学反应和热力学相关参数的确定方法,验证了该单步反应模型的正确性；采用该单步反应模型,实现了反应物胞格尺寸的定量预测,模拟了障碍物管中的火焰加速和DDT过程,发现障碍物管中存在的两种爆震波起爆方式以及从火焰加速到爆震波形成过程中的4个主要阶段,揭示了火焰面积、火焰传播速度、总能量释放率在4个阶段中的发展规律；活化能和指前因子的改变均不影响火焰加速和DDT过程的本质规律,但活化能对DDT距离、DDT时间以及火焰面积峰值的影响明显高于指前因子的影响。通过测量簧片阀上、下游压力,分析了簧片阀总压恢复系数、阻力系数、阀门开启、关闭响应时间、阀门反向密封性以及工作寿命等性能参数的主要影响因素,如阀片厚度,限位挡板倾角以及空气质量流率等,揭示了这些因素对簧片阀性能参数的影响规律；通过对簧片阀式PDE循环时间尺度分析,探讨了簧片阀式PDE极限工作频率随填充速度和燃烧室长度的变化关系；当燃烧室长度为1.3m,填充速度为当地声速340m/s时,对应的簧片阀式PDE极限工作频率为99.7Hz。
[Abstract]:Pulse Detonation Engine (PDE) has the advantages of high thermal cycling efficiency, simple structure, wide flight Maher number and self pressurization. It has broad application prospects in the field of propulsion in the future. It has attracted worldwide attention in recent years. In view of the existing problems in PDE research, the research of reed valve type pulse detonation engine is carried out through experiments and numerical simulation. The atomization characteristics of the swirling nozzles under different injection pressure were studied by PIV and Shadowgraph technology. The results show that the spray Sauter mean diameter was significantly less than the area outside the core area of the spray field; when the injection pressure increases, the core area of the spray speed increases, lateral velocity decreases and the characteristics of conical spray velocity field gradually disappeared, the average increase in the amount of spray field vortex; vortex velocity detection criterion is proposed based on weighted gain the movement of the vortex structure induced by different injection pressure spray and dimensionless vortex translational velocity variation with dimensionless time; put forward the evaluation index of the fuel oxidant mixing degree and PDE cycle stability; analysis of fuel atomization and mixture effects on PDE stability studies show that with reed valve positive effects on improving the fuel distribution and mixing, reed valve type PDE has good working stability; when the mixing degree is lower than 0.72, the PDE cycle stability with mixing When the mixing degree is greater than 0.72, increasing the mixing degree has little effect on improving the working stability of PDE. Compared with the mixing degree, the droplet average particle size has little effect on the stability of PDEI, but has a great influence on detonation velocity. The flame and pressure signals were synchronized measured by ion probe and pressure sensor, and the Deflagration to Detonation Transition (DDT) process was analyzed. The results show that the reverse thrust wall blockage ratio does not influence the nature of the DDT process, but the influence of DDT distance; because the reed valve has good reverse sealing, reed valve type PDE has shorter DDT distance; with the increase of Sauter mean diameter, induction time and induction spray detonation zone length was increased, which the induction time is larger than the increase induced zone length. Reasonable assumptions based on constant specific heat ratio and gas, a single step reaction model of variable specific heat ratio and variable gas constant; method of defining the chemical reaction and thermodynamic parameters, verifies the correctness of the single step reaction model; the single step reaction model, the quantitative prediction of reactant cell size, simulation the obstacle in the tube flame acceleration and DDT process, find the obstacles existing in the two tube detonation initiation way and from flame acceleration to detonation wave formation of 4 main stages in the process of revealing the flame area and the flame propagation speed, the total energy release rate of development in 4 stages; activation energy and the pre exponential factor changes do not affect the nature of the flame acceleration and DDT process, but the activation energy of DDT DDT distance, time and peak flame area was significantly higher than that of the pre exponential factor. Ring. By measuring the reed valve, the downstream pressure, analyzed the main influencing factors of reed valve, the total pressure recovery coefficient, drag coefficient, valve opening, the valve response time, reverse sealing and lifetime performance parameters such as closure, such as valve plate thickness, the limit plate angle and air mass flow rate, the influences of these factors on the performance parameters of the reed valve; the reed valve type PDE cycle time scale analysis, discusses the reed valve type PDE working frequency limit change with the filling speed and the length of the combustion chamber; when the combustion chamber length is 1.3m, filling speed for the local sound speed 340m/s, reed valve type PDE working frequency limit corresponding to the 99.7Hz.
【学位授予单位】：南京理工大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：V23

【参考文献】