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341.
由于旋转爆轰燃烧室具有自增压特性,可提高热力循环效率,因此将旋转爆轰燃烧室应用于燃气轮机可进一步提高系统的性能。基于非稳态雷诺时均Navier-Stokes方法,采用剪切应力输运k-ω湍流模型,建立旋转爆轰燃烧室与涡轮平面叶栅耦合计算模型,研究旋转爆轰燃烧室内的复杂波系与涡轮叶片的相互作用,分析涡轮叶栅对高频爆轰压力振荡的抑制作用。结果表明:旋转爆轰燃烧室内的燃气在涡轮叶栅内加速,并且在斜激波后的局部区域马赫数的增加更为明显。斜激波与涡轮静转子叶片的前缘、压力面、吸力面以及尾缘相互作用,由于旋转爆轰波不同的传播方向,使得斜激波与静子叶片呈相互垂直或平行,进而形成两种不同的波系结构。涡轮叶栅对高频压力振荡存在明显的抑制作用,涡轮叶栅上下游高频压力振荡幅值的衰减率达到80%以上。研究结果展示了旋转爆轰波作用下涡轮叶栅内复杂波系结构特征,并对基于爆轰燃烧推进技术的应用提供了一定的理论基础。 相似文献
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343.
《中国航空学报》2022,35(12):102-116
Mechanically pumped two-phase loop (MPTL) which is a prominent two-phase heat transfer technology presents a promising prospect in thermal control for space payload. However, transient behavior of MPTL caused by phase-change and heat sources load-on/off in simulated space environment is rarely reported. In the present study, one MPTL setup was designed and constructed, and experimentally studied. Particularly, a novel two-phase thermally-controlled accumulator integrated with passive cooling measure and three capillary structures was designed as the temperature-control device. Dynamic behavior of the start-up, temperature control, and temperature adjustment were monitored; meanwhile, thermodynamic behavior within the proposed accumulator, the operating behavior as well as the heat and mass transfer behavior between the main loop and the accumulator were revealed. The results show that the fluid management function of the capillary structures for the novel accumulator is verified. The working point of the MPTL system can be adjusted by changing the temperature control point of the accumulator and it is little influenced by external heat flux and heat sources on/off. Pressure-drop oscillations which are manifested as fluctuations of temperature and pressure can be observed after phase changing due to the compressible volume within the accumulator and the negative-slope portion of the internal pressure. 相似文献
344.
《中国航空学报》2022,35(12):89-101
The experiment is conducted to investigate the effect of expansion on the shock wave boundary layer interaction near a compression ramp. The small-angle expansion with an angle degree of 5° occurs at different positions in front of the compression ramp. The particle image velocimetry and flow visualization technology show the flow structures, velocity field, and velocity fluctuation near the compression ramp. The mean pressure distribution, pressure fluctuation, and power spectral density are measured by high-frequency response pressure transducers. The experimental results indicate that the expansion before the compression ramp position affects the shock wave boundary layer interaction to induce a large-scale separation. But the velocity fluctuation and pressure fluctuation are attenuated near the large-scale flow separation region. When the expansion occurs closer to the compression ramp, the expansion has a more significant impact on the flow. The fluctuation of velocity and pressure is significantly attenuated, and the wall pressure rise of the separation point is reduced obviously. And the characteristic low-frequency spectrum signal related to the unsteadiness of the shock wave boundary layer interaction is significantly suppressed. In addition, variation of the separation region scale at different compression angle degrees is distinctive with the effect of expansion. 相似文献
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346.
In the field of supercritical wing design, various principles and rules have been summarized through theoretical and experimental analyses. Compared with black-box relationships between geometry parameters and performances, quantitative physical laws about pressure distributions and performances are clearer and more beneficial to designers. With the advancement of computational fluid dynamics and computational intelligence, discovering new rules through statistical analysis on computers has beco... 相似文献
347.
Shining CHAN Huoxing LIU Hang SONG Fengchao LI Chongwen JIANG Zhenxun GAO 《中国航空学报》2022,35(5):247-259
A wave rotor is suitable for compact and efficient pressure-exchange between gas flows.This work measured the circumferential pressure distribution of the rotor/stator interfaces and utilized a CFD method to simulate the unsteady pressure waves. The experimental and CFD results showed some slopes in the circumferential pressure distributions, and the slopes indicated the traces of specific unsteady pressure waves. Such traces varied regularly if the rotational speed varied within a range from-11... 相似文献