Studies on spray characteristics of barbotaged atomizer

为了研究静止空气中气泡雾化喷嘴的液雾特性，利用粒子多普勒分析仪（PDA）和Mie散射显示法，对气泡雾化喷嘴在水压2.5 MPa和3.4 MPa条件下，较宽气液比范围内的液雾的张角、粒度及速度分布进行了测量，分析了水压、气液比、两股射流相互作用对液雾的影响。结果表明，气泡对液体射流的雾化具有较大的增强作用，同时发现在一临界气液比（介于3% ～ 4%之间），当气液比达到临界值后，射流的雾化突然增强，且运行稳定

Research on three-dimensional scramiet inlet

The three-dimensional compression scramjet inlet has been investigated by using surface oil dot visualization and numerical simulation. The research has revealed the details of the internal flow pattern, which included the structure of the shock waves, the spillage, the spatial vortical structures, and the boundary layer separations etc.. These features determined the performance of the inlet, which gave the mass flow capture ratio of 0.86, total pressure recovery of 0.41. The results showed that the arrangement of the shocks is critical for such kind of inlet. More researches have been carried out to investigate the effect of the cowl shape, and the results showed the flow field would be changed little for the cowls with different shapes but the same internal contraction ratios

Thermochemical non-equilibrium flow characteristics of high Mach number inlet in a wide operation range

The high-temperature non-equilibrium effect is a novel and significant issue in the flows over a high Mach number (above Mach 8) air-breathing vehicle. Thus, this study attempts to inves-tigate the high-temperature non-equilibrium flows of a curved compression two-dimensional scram -jet inlet at Mach 8 to 12 utilizing the two-dimensional non-equilibrium RANS calculations. Notably, the thermochemical non-equilibrium gas model can predict the actual high-temperature flows, and the numerical results of the other four thermochemical gas models are only used for com-parative analysis. Firstly, the thermochemical non-equilibrium flow fields and work performance of the inlet at Mach 8 to 12 are analyzed. Then, the influences of high-temperature non-equilibrium effects on the starting characteristics of the inlet are investigated. The results reveal that a large sep-aration bubble caused by the cowl shock/lower wall boundary layer interaction appears upstream of the shoulder, at Mach 8. The separation zone size is smaller, and its location is closer to the down-stream area while the thermal process changes from frozen to non-equilibrium and then to equilib-rium. With the increase of inflow Mach number, the thermochemical non-equilibrium effects in the whole inlet flow field gradually strengthen, so their influences on the overall work performance of the high Mach number inlet are more obvious. The vibrational relaxation or thermal non -equilibrium effects can yield more visible influences on the inlet performance than the chemical non-equilibrium reactions. The inlet in the thermochemical non-equilibrium flow can restart more easily than that in the thermochemical frozen flow. This work should provide a basis for the design and starting ability prediction of the high Mach number inlet in the wide operation range. (c) 2023 Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/)

GJF超声速管风洞/激波风洞

主要开展与高温气体效应、高温热化学反应机理、高温辐射、以及气动光学有关的基础研究，主要技术指标: 试验马赫数M20-25，总温11000K，可以产生7-10km/s超高速气流，试验时间500微秒，喷管出口直径Ф350mm？

液体碳氢燃料超然的数值模拟

液体碳氢燃料，特别是煤油，由于便于贮存、携带，安全性好，对马赫数小于8的飞行器的推进系统有很大的实用价值。截止目前，液体碳氢燃料超燃问题的研究主要依靠实验手段，由于液滴在超声速气流中的运动及碳氢燃料化学反应机理的复杂性，关于液体碳氢燃料超声速燃烧的数值模拟一直没有很好地发展。本文利用KIVA-3较完善的液雾模型，在其基础上，对其网格生成程序、湍流模型及部分液雾模型等进行了改进，考虑了气相可压缩性、流场不均匀性及液滴变形对液滴运动的影响，采用随机轨道模型全面考察了液滴的二次破碎、湍流扩散、蒸发、液滴间碰撞及气液相间棍合作用，同时引入了CHEMKIN II软件包，以完善化学反应的数值模拟，完成了对液体碳氢燃料超声速燃烧问题的应用程序的开发。通过对超声速气流中凹腔流和横向空气射流流场的模拟对该程序在流场计算上的可靠性进行了校验，计算结果反映了这两个典型流动问题的流场特征，与实验结果取得基本一致。对超声速气流中液体横向射流的数值模拟发现，液体射流与气流之间存在着强烈的相互作用，在液体射流喷口上游出现一道三维弓形激波，气流速度、温度受液雾的影响不断下降，而液滴在进入气流中不久就破碎成很小的子液滴，并迅速吸热蒸发。与液雾结构的纹影图像和液雾穿透的实验结果对比显示，数值计算结果基本合理。在冷态两相流动计算的基础上，进一步对氢引导火焰与凹腔相结合的液体碳氢燃料的超声速燃烧过程进行了数值模拟，结果表明数值模拟定性反映了煤油超燃现象，体现了引导氢和凹腔在煤油超燃过程中所起到的点火和稳焰的重要作用

Numerical Research on Liquid Spray in Supersonic Cross Flow

Numerical simulation was conducted to characterize the kerosene spray injecting into supersonic cross flow, especially focusing on the aerodynamic secondary breakup effect of the supersonic cross flow on the initial droplets. It was revealed that the initial parent drops were broken up into small drops whose diameter is about O(10) micrometers soon after they entered into the supersonic cross flow. During the appropriate range of initial drop size, the parent droplets would be broken up into small drops with the same magnitude diameter no matter how large the initial drops SMD was

气泡雾化喷嘴液雾特性

为了研究静止空气中气泡雾化喷嘴的液雾特性，利用粒子多普勒分析仪(PDA)和Mie散射显示法，对气泡雾化喷嘴在水压2．5MPa和3．4MPa条件下，较宽气液比范围内的液雾的张角、粒度及速度分布进行了测量，分析了水压、气液比、两股射流相互作用对液雾的影响。结果表明，气泡对液体射流的雾化具有较大的增强作用，同时发现存在-临界气液比(介于3％～4％之间)，当气液比达到临界值后，射流的雾化突然增强，且运行稳定

Numerical Study on Kerosene Spray in Supersonic Flow

Numerical simulation was conducted to study the kerosene spray characteristics injecting into supersonic cross flow. The verification of the simulation was carried out by experimental Schlieren image, and the agreement was obtained by compared the spray plume pictures. Furthermore, the aerodynamic secondary breakup effect of the supersonic cross flow on the initial droplets was investigated. It was revealed that the initial parent drops were broken up into small drops whose diameter is about O(10) micrometers soon after they entered into the supersonic cross flow. During the appropriate range of initial drop size, the parent droplets would be broken up into small drops with the same magnitude diameter no matter how large the initial drops SMD was

斜爆轰波黏性流场和起爆演化的数值研究

为探究黏性效应对斜爆轰波波阵面的影响，认识斜爆轰波起爆过程的特性，基于高分辨率求解器，开展斜劈诱导斜爆轰波的无黏/有黏数值计算。发现有黏计算条件下惰性斜激波波角值明显大于无黏计算，同时耦合下游分离泡的影响，使得斜激波后诱导点火长度减小。由于有黏计算中壁面上分离泡的分离/再附激波自身具有不稳定性，分离/再附激波与斜爆轰波波阵面作用更易促使类胞格结构形成。斜爆轰波的起爆可认为是由斜激波诱导的燃烧波与斜激波碰撞引发的，形成的斜爆轰波继而在三波点牵引下向外膨胀；特别地，燃烧波强度对最终准稳态流场中强过驱斜爆轰波区域尺度有明显影响

Numerical simulation of kerosene spray in supersonic cross flow

为了对超声速气流中液体横向射流进行数值模拟，采用Eulerian-Lagmngian方法描述气液两相流动现象，用随机轨道模型追踪液滴的运动历程，并考虑气流可压缩性、流场不均匀性及液滴变形对液滴运动的影响，开发了相应的计算程序。计算结果发现，液体射流与气流之间存在着强烈的相互作用，液滴在进入气流中不久就破碎成很小的子液滴，受煤油液雾的影响气流速度、温度急剧下降，同时在喷孔上游出现～道弓形激波。与液雾结构的纹影图像和液雾穿透的实验结果对比显示，数值计算结果基本合理