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采用9组分19步基元反应模型,不考虑黏性、热传导和扩散效应等对流动的影响,对以氢气和氧气为反应混合物的旋转爆震发动机内流场进行计算,研究轴向长度对发动机性能的影响.研究表明:在一定范围内轴向长度对发动机比冲影响很小,轴向长度过长时会降低发动机比冲.轴向长度对爆震波的压力形成影响很大,轴向长度过小时,爆震波压力不高,过大时,会导致斜激波压力衰减.随着轴向长度的增加,由于膨胀的作用,出口的压力不断降低,轴向长度为200mm时,出口的平均速度最大,此时发动机比冲也达到最大值;周向速度明显减小,降低了周向速度对发动机的不利影响;推力密度峰值逐渐下降;激波前后密度差逐渐减小,这使发动机的推力偏心矩也不断降低,从而可有效地减小角散布等不利影响.
The nine-component 19-step reaction model was used to calculate the flow field in a rotary detonation engine with hydrogen and oxygen as the reaction mixture without considering the influence of viscosity, heat conduction and diffusion on the flow. The axial length pair Engine performance.The results show that the axial length has little effect on the engine specific impulse in a certain range and the engine specific impulse decreases when the axial length is too long.The axial length has a great influence on the pressure of the detonation wave, When the length is too short, the pressure of the detonation wave is not high, and when it is too large, the pressure of the oblique shock will be attenuated. As the axial length increases, the pressure at the outlet decreases continuously due to the expansion. When the axial length is 200 mm, The average speed of the maximum, then the engine also reached the maximum specific impulse; circumferential speed was significantly reduced, reducing the adverse effects of the circumferential speed on the engine; thrust density peak gradually decreased; before and after the shock wave density difference gradually reduced, which makes the engine Of the thrust eccentric moment is also continuously reduced, which can effectively reduce the angular spread and other adverse effects.