Nozzle effects on performance of pulse detonation engines
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摘要: 采用热力学循环分析方法, 从理论上推导了脉冲爆轰发动机(pulse detonationengine, PDE)不完全膨胀条件下的热效率公式, 并定量考察了不同燃烧室初始温度下热循环效率随出口压力比的变化, 研究表明气体膨胀越完全, 工质的热循环效率越高. 应用数值模拟方法分别研究了收缩-扩张喷管和扩张喷管, 比较了它们对PDE推力和比冲的影响, 考察了它们在PDE各个循环阶段的作用. 此外, 还分析了收缩-扩张喷管收缩段引起的反射激波的影响, 理论上反射激波会降低PDE热循环效率和比冲, 但当反射激波马赫数小于1.5时, 对PDE热循环效率的影响很小, 其正面作用占优.
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关键词:
- 计算流体动力学
Abstract: Thermal efficiency of pulse detonation engines (PDEs) wasformulated with thermodynamic cycle analysis when the exhaust flow is notperfectly expanded, the quantitative relation of PDEs thermal efficiency andnozzle exit pressure ratio was examined under different initial combustortemperature, the closer the exhaust pressure gets to ambient pressure, thehigher efficiency PDE could achieve. Effects of the CD-nozzle and theD-nozzle on PDE performance are investigated by numerical simulations; theobtained thrust and impulse of PDE are compared with each other fordifferent cases, and nozzle effects on each period of the PDE cycle are alsoinvestigated. In addition, the influence of reflected shock waves from theconvergent section of a CD-nozzle is also studied to show that the reflectedshock waves actually affect the thermodynamic cycle efficiency more or less,but when the shock Mach number is less than 1.5, PDE thermal efficiencyreduction is quite slight and the positive effects of nozzle are dominated.-
Key words:
- computational fluid dynamics
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