超声速气液两相流动中斜爆震的起爆与燃烧稳定性的数值模拟研究

Oblique detonation combustion chamber with liquid fuel has the advantages of pressure-gain combustion and high thermal cycling efficiency. The gas-liquid two-phase oblique detonation inside the combustion chamber involves complicated physicochemical processes, such as spray, turbulence, shock wave and chemical reaction. The physical mechanisms behind them are complicated, and the influence regularities for the detonation initiation, self-sustaining propagation and combustion stability are not clear. Studying the triggering mechanism and combustion stability of oblique detonation is of great importance to the development of accurate numerical model as well as further optimization design and performance analysis for oblique detonation combustion chamber. Based on the Eulerian-Lagrangian framework, the present project is intended to develop high-order accuracy numerical methods for high-speed compressible two-phase flow and detonation, and to realize the numerical simulation for gas-liquid two-phase oblique detonation with high-resolution behavior. The physical mechanisms of the initiation, self-sustaining structure and combustion stability of gas-liquid two-phase oblique detonation will be studied based on the paramount simulation data. The combustion mechanisms and influence regularities will be summarized for different inflow conditions and spray parameters within the working envelope of oblique detonation combustion chamber. Theoretical guidance will be provided for the engineering application of gas-liquid two-phase oblique detonation combustion.

采用液体燃料的斜爆震燃烧室具有燃烧自增压和热效率高等优点。气液两相斜爆震涉及液雾、湍流、激波、化学反应等多个物理化学过程的相互作用，物理机理复杂，起爆、自持传播以及燃烧稳定性等规律尚未清晰。研究两相斜爆震的触发机制以及燃烧稳定性，对于斜爆震燃烧室的优化设计与性能分析具有重要意义。本项目将基于连续相流体欧拉-离散相液滴拉格朗日的混合模型，发展适用于高速可压缩两相流动与爆震燃烧的高精度数值方法，实现气液两相斜爆震燃烧过程的精细化数值模拟；基于所得数据，研究气液两相斜爆震燃烧的起爆、自持结构与燃烧稳定性的物理机理，总结斜爆震燃烧室工作包线内不同来流与喷雾参数下气液两相斜爆震燃烧机理与影响规律，为气液两相斜爆震燃烧的工程应用提供理论依据。

采用液体燃料的斜爆震燃烧室具有燃烧自增压和热效率高等优点。超声速气流中斜爆震的形成与斜爆震稳定性均关系着燃烧室乃至发动机的正常运转。然而，采用液体燃料的气液两相斜爆震燃烧，其起爆机制仍然不清晰，两相斜爆震稳定性机理尚不明确。本项目以斜爆震燃烧室内气液两相斜爆震为应用背景，对起爆过程以及燃烧稳定性机理开展研究。面向发动机实际来流条件，本项目针对不同来流参数以及燃料雾化参数下斜爆震的起爆、波系结构特性与变化规律开展数值模拟研究。研究发现了气液两相斜爆震波在非稳态来流参数下可以实现动态自持稳定的特性，揭示了来流气动热力学参数如压力、马赫数以及燃料雾化参数如预蒸发度、当量比、液滴尺寸影响下的起爆距离以及波系特性的变化规律。由于液滴蒸发吸热和化学反应释热的竞争关系，研究结论与以往的气相斜爆震结果有很大差异。研究得到的相关物理规律与影响因素，为发展合理的流动与稳定燃烧控制手段以及气液两相斜爆震燃烧的工程应用打下基础。