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

了解超声速混合层内的混合过程对超燃冲压发动机的研究具有重要意义。为了阐明超声速混合层内的混合过程，已经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。混合层等效比分布数据较少，测量难度较大。提出了一种新的评价氢-气超声速流动中H_2混合条件的方法。本文报道了用恒高温铂丝催化反应评价湍流超音速混合层的新技术。该技术已被开发并应用于测量超声速流中斜注氢产生的超声速混合流中的H_2浓度。为研究超燃冲压发动机燃烧室内的混合流场，采用后向台阶向1.8马赫冷气流正常注入氢气。在恒温铂丝上进行催化反应，测定了H_2和O_2的混合条件。研究H_2混合条件是一项新技术。通过在空间上测量催化剂表面H_2和/或O_2的浓度，从而清除H_2和O_2的局部混合条件，从而得到催化反应的放热量。结果表明，该区存在两个核心区。为超声速燃烧提供了良好的混合条件。阐明了核心区沿流动方向的发展规律，说明了本研究提出的新方法对超声速混合流场中氢浓度的评价是非常有用的。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