中心锥对液态燃料旋转爆轰发动机工作过程与性能的影响

为分析中心锥对液态燃料旋转爆轰发动机(RDE)工作特性的影响，在环形阵列式RDE上，以汽油/富氧空气为工质，开展了液态燃料RDE实验研究。测量发动机在不同中心锥位置l/L（l为燃烧室内壁面等直段末端与燃烧室外壁面末端的距离，L为燃烧室外壁面长度）和中心锥锥角θ时的一维推力，分析了推力和燃料比冲的变化趋势。实验结果表明：改变l/L和θ未对旋转爆轰波传播模态产生影响，各工况下旋转爆轰波均为双波对撞模态；受预爆轰管切向喷注孔的影响，双波对撞点无法稳定于预爆轰管出口附近；爆轰波传播速度和频率随中心锥位置的前移呈下降趋势，当l/L=0%、θ=20°时，推力和燃料比冲分别为951.6 N和1 151.8 s， 为所有实验工况中最大值；随着l/L或θ增大，爆轰产物轴向膨胀距离变短，中心锥头部突扩位置处膨胀波影响增强，外流场中心锥型面约束作用减弱且高温燃气径向膨胀增强，发动机出口高温燃气轴向分速度逐渐减小，发动机推力和燃料比冲逐渐减小；当l/L>25.5%或θ>40°时，受熄爆再起爆和膨胀波增强影响，发动机推力和燃料比冲下降速率增大。

Effect of Central Cone on Working Process and Performance of Liquid-fueled Rotating Detonation Engine

The gasoline/oxygen-enriched air is used as working medium in ring-array rotating detonation engine (RDE) to study the effect of the central cone position on working process and performance of liquid-fueled RDE. The liquid-fueled RDE was studied through experiment. The one-dimensional thrusts of rotating detonation engine at different positions of central cone and its angles were measured，and the variation tendencies of thrust and fuel specific impulse were analyzed. The experimental results show that the position and angle of central cone have little effect on the propagation mode of rotating detonation wave, and the rotating detonation waves are always in double-wave collision modes. Since the double-wave collision point is affected by the tangential injection hole of the pre-detonator, it cannot be stabilized near the outlet of pre-detonator. The velocity and frequency of detonation wave decrease as the central cone moves forward. For l/L=0% where l is the distance from the equal straight segment end of internal wall surface to the end of external wall surface in combustion chamber, L is the length of external wall surface of combustion chamber and θ=20°, the thrust and fuel specific impulse are 951.6 N and 1 151.8 s, respectively, which are the maximum values under all experimental conditions. As the position l/L or angle θ central cone increases, the axial expansion distance of detonation products becomes shorter, the effect of expansion wave is enhanced at the sudden expansion position of central cone, the constraint effect of central cone surface in external flow field is weakened, and the radial expansion of high temperature gas is enhanced. The axial partial velocity of high temperature gas at outlet decreases gradually, and the thrust and fuel specific impulse decrease gradually. For l/L>25.5% or θ>40°, the lowering speeds of thrust and fuel specific impulse increase due to the re-initiation and expansion wave enhancement.