多循环脉冲爆震载荷作用下爆震室强度分析与结构优化

利用数值模拟获取的完整爆震循环载荷,以及爆震室有限元模型,计算分析了爆震室多循环工作时的等效应力,依据热平衡状态实测温度数据计算了温度场的影响,并对爆震室进行了壁厚优化.发现多循环工作时,爆震室最大等效应力比单次爆震时略大,但同一位置处差值不超过4%;同一位置处等效应力呈周期性变化,不同循环的最大等效应力基本不变;沿爆震波传播方向,等效应力的最大值逐渐增大.频率在10~50Hz变化时,同一位置处最大等效应力值基本不变.当假设爆震室径向温度相同且轴向可自由膨胀时,温度对应力几乎没有影响,但相同应力所产生的应变增加. 

Strength analysis and structural optimization of detonation combustor to multi-cycle pulse detonation loading

The equivalent stress of the detonation combustor was computed and researched using the axisymmetric finite element modal and whole cycle pressure obtained by numerical simulation.The effect of the temperature was calculated using the measured thermal equilibrium temperature data,and the primary optimization of the thickness was completed for given fatigue life.It is found that the equivalent stress of the detonation combustor to multi-cycle detonation loading is a little bigger than that to single cycle detonation loading,and the difference of the same position is less than 4%.The equivalent stress of the detonation combustor at the same position is periodic when the PDE(pulse detonation engine) works circularly,and the maximal equivalent stress in every cycle is nearly equal.The maximal equivalent stress has an increscent trend along with the spread of detonation wave.The maximal equivalent stress at the same position is nearly equal when the frequency changes among 10~50Hz.The equivalent stress with temperature is nearly equal to that without temperature when it is assumed that the detonation combustor has the same temperature in the radial direction and can expand freely in the axial direction,but the equivalent strain increases.