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Chemical oxygen iodine laser (COIL) is a high-power laser with potential applications in both military as well as in the industry. COIL is the only chemical laser based on electronic transition with a wavelength of 1.315 μm, which falls in the near-infrared (IR) range. Thus, COIL beam can also be transported via optical fibers for remote applications such as dismantling of nuclear reactors. The efficiency of a supersonic COIL is essentially a function of mixing specially in systems employing cross-stream injection of the secondary lasing (I2) flow in supersonic regime into the primary pumping (O21Δg) flow. Streamwise vorticity has been proven to be among the most effective manner of enhancing mixing and has been utilized in jet engines for thrust augmentation, noise reduction, supersonic combustion, etc. Therefore, a computational study of the generation of streamwise vorticity in the supersonic flow field of a COIL device employing a winglet nozzle with various delta wing angles of 5°, 10°, and 22.5° has been carried out. The study predicts a typical Mach number of approximately 1.75 for all the winglet geometries. The analysis also confirms that the winglet geometry doubles up both as a nozzle and as a vortex generator. The region of maximum turbulence and fully developed streamwise vortices is observed to occur close to the exit, at x/λ of 0.5, of the winglets making it the most suitable region for secondary flow injection for achieving efficient mixing. The predicted length scale of the scalloped mixer formed by the winglet nozzle is 4λ. Also, the winglet nozzle with 10° lobe angle is most suitable from the point of view of mixing developing cross-stream velocity of 120 m/s with acceptable pressure drop of 0.7 Torr. The winglet geometry with 5° lobe angle is associated with a low cross-stream velocity of 60 m/s, whereas the one with 22.5° lobe angle is associated with a large static and total pressure drop of 1.87 and 9.37 Torr, respectively, making both the geometries unsuitable for COIL systems. The experimental validation shows a close agreement with the computationally predicted values. The studies for the most suitable 10° lobe angle geometry show an observed Mach number of 1.72 with an improved mixing efficiency of 74% due to the occurrence of predicted streamwise vortices in the flow. 相似文献
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对应用于单重态氧发生器 (SOG)O2 (1 △ )绝对浓度测量的红外辐射 量热法从理论和实验两方面进行了改进 ,修正了过去忽略O2 (1 △ )温度变化所造成的系统误差 .此外 ,还详细介绍了在短时间工作的SOG上进行O2 (1△ )绝对浓度测量所必须的自动平衡电桥装置 ,并通过氧气热容的测量检验了它的可靠性 .最后的误差分析表明 ,O2 (1 △ )绝对浓度的相对误差为± 16% ,误差主要来源于光度池红外信号、压力和温度的测量 . 相似文献
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R. K. Tyagi R. Rajesh Gaurav Singhal Mainuddin A. L. Dawar M. Endo 《Optics & Laser Technology》2003,35(5):395-399
Supersonic Chemical Oxy-iodine Laser has been developed using a Singlet Oxygen Generator (SOG) with a novel approach. Generated singlet oxygen is taken out of the SOG at an angle of 40° to avoid the problem of carry over of droplets, which is one of the major drawbacks of horizontal system. The system has been operated up to 22 mmol/s chlorine flow rates. Chlorine utilization and singlet oxygen observed have been more than 90% and 60%, respectively. The observed maximum output power was 350 W, thus yielding a chemical efficiency of 17.5%. 相似文献
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Zongmin Hu Junming Lā Zonglin Jiang Rho-Shin Myong Tae-Hwan Cho 《Acta Mechanica Sinica》2008,24(2):133-142
Laser performance is greatly dependent on its operating conditions due to the strong coupling among multi- physics such as gas-dynamics, chemical reaction kinetics and optics in the mixing nozzle of COIL. In this paper, 3D CFD technology is used to simulate the mixing and reactive flow of subsonic cross jet scheme at different conditions. Results obtained show that the jet penetration depth plays a dominant role in the spatial distribution of small signal gains. In the case of over-penetration, unsteady flow structures are induced by impinging between the opposing jets. The optimum spatial distribution of the chemical performance cannot be obtained even if the full penetration condition is achieved through the subsonic transverse jet mixing scheme in the COIL nozzle flow. 相似文献