Catalytic Combustion in Low Temperature Supersonic Mixing Layer on Scramjet Engine Model

了解超音速混合层中的混合过程对超燃冲压发动机的研究具有重要意义。到目前为止，人们对超音速混合层中的混合过程进行了大量的实验和数值研究。大多数实验研究都集中在与混合层有关的速度分布上，并对流动显示结果进行了评价。同时，随着CPD的发展，数值结果已经能够给出H_2当量比(H_2浓度分布)的空间数据。由于混合层中当量比分布的数据较少，给测量带来了困难。本研究提出了一种新的氢气-空气超音速流动中氢气混合状况的评价方法。报道了用恒温铂丝催化反应评价湍流超音速混合层的新技术。该技术已成功地应用于…中氢气浓度的测量通过在超音速气流中倾斜喷氢产生更多的超音速混合流，在马赫数为1.8的冷空气中采用后向台阶喷射氢气，以研究超燃冲压发动机燃烧室内的混合流场。用恒温铂丝催化反应测定了H_2和O_2的混合情况，这是研究H_2混合条件的一种新技术。通过测量催化剂表面H_2和O_2浓度对应的催化反应放热量，明确了H_2和O_2的局部混合条件。结果表明，存在两个核心区。对于超音速燃烧，在混合层内具有良好的混合条件。文中还阐明了核心区沿流动方向的发展规律，并阐明了本文提出的新技术对超音速混合流场中氢气浓度的计算是非常有用和容易的。较少

It is important for scramjet engine study to understand the mixing process in supersonic mixing layer. So far, many experimental and numerical studies have been conducted to clarify the mixing process in supersonic mixing layer. Most of experimental studies have focused in the velocity distributions concerned with mixing layer, and also evaluated the flow visualization results. Meanwhile, with CPD developing, numerical results have been able to give the spatial data of equivalence ratio of H_2 (distribution of H_2 concentration). There is less data of distribution of equivalence ratio in mixing layer as reason for the difficulty of measuring it. This study proposes a new evaluation technique for the mixing condition of H_2 in hydrogen-air supersonic flow. We have reported the new technique for the evaluation of turbulent supersonic mixing layer using catalytic reaction on constant high temperature Pt wire. This technique has been developed and is applied to measure H_2 concentration in … More supersonic mixing flow produced by inclined hydrogen injection into a Supersonic flow.Hydrogen was injected normally to a Mach 1.8 cold air stream with a backward-facing step to investigate mixing flow field in a scramjet combustor. Catalytic reaction on constant temperature Pt wire was used to measure the mixing condition of H_2 and O_2. It was new technique to investigate H_2 mixing condition. The amount of heat release due to the catalytic reaction, which corresponds to the concentration of H_2 and/or O_2 on the surface of the catalyst, was measured spatially so that the local mixing condition of H_2 and O_2 was cleared. The results showed that there were two core regions. which would have good mixing condition for supersonic combustion, in the mixing layer. The development of core regions along flow direction was also clarified It was also clarified that the new teclmique proposed in the present study was very useful and easy to evaluate the hydrogen concentration in supersonic mixing flow field. Less