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Numerical Study on Regenerative Cooling Characteristics of Kerosene Scramjets
International Journal of Aerospace Engineering ( IF 1.4 ) Pub Date : 2020-10-28 , DOI: 10.1155/2020/8813929 Xuan Jin 1 , Chibing Shen 1 , Xianyu Wu 1
International Journal of Aerospace Engineering ( IF 1.4 ) Pub Date : 2020-10-28 , DOI: 10.1155/2020/8813929 Xuan Jin 1 , Chibing Shen 1 , Xianyu Wu 1
Affiliation
The use of kerosene-based regenerative cooling for scramjet has been found widespread attention due to its inherent nature of high energy utilization efficiency and good thermal protection performance. In order to provide a reference for the later design and experiments, three-dimensional turbulence simulations and sensitivity analysis were performed to determine the effects of three operating mode parameters, heat flux, mass flow rate, and outlet pressure, on the regenerative cooling characteristics of kerosene scramjets. A single rectangular-shaped channel for regenerative cooling was assumed. The RNG k-ε turbulence model and kerosene cracking mechanism with single-step global reaction were applied for the supercritical-pressure heat transfer of kerosene flows in the channel. Conclusions can be drawn that as the kerosene temperature rises along the channel, the decrease of fluid density and viscosity contributes to increasing the fluid velocity and heat transfer. When the kerosene temperature is close to the pseudocritical temperature, the pyrolysis reaction results into the rapid increase of fluid velocity. However, the heat transfer deterioration occurs as the specific heat and thermal conductivity experience their turning points. The higher heat flux leads to lower heat transfer coefficient, and the latter stops rising when the wall temperature reaches the pseudocritical temperature. The same rising trend of the heat transfer coefficient is observed under different outlet pressures, but the heat transfer deterioration occurs earlier at smaller outlet pressure for the reason that the corresponding pseudocritical temperature decreases. The heat transfer coefficient increases significantly along with the rise of the mass flow rate, which is mainly attributable to the increase of Reynolds number. Quantitative results indicate that as the main influence factors, the heat flux and mass flow rate are respectively negatively and positively relative to the intensification of heat transfer, but outlet pressure always has little effects on cooling performance.
中文翻译:
煤油超燃器蓄冷特性的数值研究
由于其高能量利用效率和良好的热保护性能的内在本质,将煤油基蓄冷冷却技术用于超燃冲压发动机已引起广泛关注。为了给以后的设计和实验提供参考,进行了三维湍流模拟和灵敏度分析,以确定三个工作模式参数(热通量,质量流量和出口压力)对冷却塔的再生冷却特性的影响。煤油超燃冲压发动机。假设有一个用于再生冷却的矩形通道。RNG k- ε采用湍流模型和单步全局反应煤油裂解机理对通道内煤油流的超临界压力传热进行了研究。可以得出结论,随着煤油温度沿通道的升高,流体密度和粘度的降低有助于增加流体速度和传热。当煤油温度接近假临界温度时,热解反应导致流体速度快速增加。然而,当比热和导热率经历其转折点时,传热恶化发生。较高的热通量导致较低的传热系数,并且当壁温达到伪临界温度时,后者不再上升。在不同的出口压力下观察到相同的传热系数上升趋势,但是由于相应的伪临界温度降低,所以在较小的出口压力下较早发生传热恶化。传热系数随着质量流量的增加而显着增加,这主要归因于雷诺数的增加。定量结果表明,作为主要影响因素,热通量和质量流率相对于传热的增强分别为负和正,但出口压力始终对冷却性能几乎没有影响。但是由于相应的假临界温度降低,在较小的出口压力下传热恶化较早发生。传热系数随着质量流量的增加而显着增加,这主要归因于雷诺数的增加。定量结果表明,作为主要影响因素,热通量和质量流率相对于传热的增强分别为负和正,但出口压力始终对冷却性能几乎没有影响。但是由于相应的假临界温度降低,在较小的出口压力下传热恶化较早发生。传热系数随着质量流量的增加而显着增加,这主要归因于雷诺数的增加。定量结果表明,作为主要影响因素,热通量和质量流率相对于传热的增强分别为负和正,但出口压力始终对冷却性能几乎没有影响。
更新日期:2020-10-30
中文翻译:
煤油超燃器蓄冷特性的数值研究
由于其高能量利用效率和良好的热保护性能的内在本质,将煤油基蓄冷冷却技术用于超燃冲压发动机已引起广泛关注。为了给以后的设计和实验提供参考,进行了三维湍流模拟和灵敏度分析,以确定三个工作模式参数(热通量,质量流量和出口压力)对冷却塔的再生冷却特性的影响。煤油超燃冲压发动机。假设有一个用于再生冷却的矩形通道。RNG k- ε采用湍流模型和单步全局反应煤油裂解机理对通道内煤油流的超临界压力传热进行了研究。可以得出结论,随着煤油温度沿通道的升高,流体密度和粘度的降低有助于增加流体速度和传热。当煤油温度接近假临界温度时,热解反应导致流体速度快速增加。然而,当比热和导热率经历其转折点时,传热恶化发生。较高的热通量导致较低的传热系数,并且当壁温达到伪临界温度时,后者不再上升。在不同的出口压力下观察到相同的传热系数上升趋势,但是由于相应的伪临界温度降低,所以在较小的出口压力下较早发生传热恶化。传热系数随着质量流量的增加而显着增加,这主要归因于雷诺数的增加。定量结果表明,作为主要影响因素,热通量和质量流率相对于传热的增强分别为负和正,但出口压力始终对冷却性能几乎没有影响。但是由于相应的假临界温度降低,在较小的出口压力下传热恶化较早发生。传热系数随着质量流量的增加而显着增加,这主要归因于雷诺数的增加。定量结果表明,作为主要影响因素,热通量和质量流率相对于传热的增强分别为负和正,但出口压力始终对冷却性能几乎没有影响。但是由于相应的假临界温度降低,在较小的出口压力下传热恶化较早发生。传热系数随着质量流量的增加而显着增加,这主要归因于雷诺数的增加。定量结果表明,作为主要影响因素,热通量和质量流率相对于传热的增强分别为负和正,但出口压力始终对冷却性能几乎没有影响。