固体超燃冲压发动机燃烧模态转换研究

Investigation of combustion mode transition on solid rocket scramjet

对固体超燃冲压发动机的模态转换现象和燃烧室工作特性开展了地面直连试验和数值模拟研究。试验在Ma=6,25 km的条件下实现燃烧模态由超燃转换为亚燃,再转换为超燃的动态变化。数值模拟获得了对应燃烧模态下发动机燃烧室的流场参数变化及工作特性。将隔离段出口马赫数作为燃烧模态判别准则,基于隔离段绝热假设计算出隔离段出口马赫数,实现发动机燃烧模态的实时判别,并通过数值模拟结果验证了该方法的可行性。试验结果表明,改变燃料喷注方式能够实现燃烧模态的变化,亚燃模态下的性能明显高于超燃模态。数值结果表明,发动机隔离段及燃烧室内激波强度和位置受到横向射流与燃烧释热的共同影响,且不同燃烧模态下影响激波的主要因素不同。发动机燃烧室工作在亚燃模态下的性能最佳,总压恢复系数为0.44,总燃烧效率为0.79。其中,亚燃模态下硼颗粒和碳颗粒的燃烧效率分别为0.78和0.65。

The mode transition and combustor operation characteristics of a dual-mode solid rocket scramjet were studied by means of experimental and numerical approaches.Transition of combustion mode was experimentally captured to be consistent with the simulated conditions of Mach number of 6 and altitude of 25 km.Operation characteristics of the dual-mode solid rocket scramjet under different combustion modes were examined.The numerical method was validated by the experimental data.According to experimental results,various phenomena can be observed under different combustion modes.Additionally,numerical results show that the intensity and position of shock wave are affected by transverse jet and heat release.Furthermore,the combustor performance is superior when it operates in ram-mode,the total pressure recovery coefficient is 0.44 and the total combustion efficiency is 0.79.The combustion efficiency of boron particles and carbon particles is 0.78 and 0.65,respectively.