In this paper, a novel experimental investigation was conducted to enhance the combustion of boron-containing fuel-rich mixture by steam reforming in a supersonic flow. The ground direct-connected experiments were designed to simulate a flight condition at Mach number 5.9 and an altitude of 25 km. The operating characteristics and performance evaluation of the scramjet combustor were analyzed and discussed. The experimental results demonstrate that steam reforming can enhance the combustion of boron-containing fuel-rich mixtures in the supersonic flow. The performance of the combustor is firstly enhanced and then weakened with the increase of the steam-fuel ratio. The optimal steam-fuel ratio is approximately 0.189, which maximizes performance. At this steam-fuel ratio, combustion efficiency reaches 0.451, which is 9.9 % and 7.4 % higher than steam-fuel ratios of 0 and 0.395, respectively. The possible mechanism of steam reforming promoting boron combustion in the supersonic mainstream is explained. Steam accelerates the removal of the liquid oxide layer surrounding the boron particle, then combines with oxygen to produce hydrogen with good ignition-combustion characteristics and a new oxide layer. The cycle continues until the boron burns out. These conclusions can promote an understanding of enhancing the combustion of boron-containing fuel-rich mixture by steam reforming in the supersonic flow.

中文翻译：

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超音速流中蒸汽重整强化含硼燃料混合物的燃烧

在本文中，进行了一项新颖的实验研究，以通过超音速流中的蒸汽重整来增强含硼燃料富集混合物的燃烧。地面直连实验旨在模拟马赫数5.9、高度25公里的飞行条件。对超燃冲压发动机燃烧室的运行特性和性能评价进行了分析和讨论。实验结果表明，蒸汽重整可以增强含硼燃料富集混合物在超音速流中的燃烧。燃烧室的性能随着汽燃比的增大先增强后减弱。最佳蒸汽燃料比约为 0.189，可最大限度地提高性能。在此汽燃比下，燃烧效率达到0.451，比汽燃比0和0.395分别提高9.9%和7.4%。解释了蒸汽重整促进超音速主流中硼燃烧的可能机制。蒸汽加速去除硼颗粒周围的液态氧化层，然后与氧气结合产生具有良好点火燃烧特性的氢气和新的氧化层。这个循环一直持续到硼烧尽为止。这些结论可以促进对超音速流中蒸汽重整增强含硼燃料富混合物燃烧的理解。