Development of exhaust gas pressure recovery system for supersonic-flow chemical oxygen-iodine lasers

超音速流化学氧碘激光器（S-COIL）在工业应用中的障碍之一是排气压力低，这就需要一个巨大的压力恢复系统来实现废工作混合物的排放。为了减小系统的尺寸，应在较高的总压下通过使用活性氧碘增益介质来提高废气的滞止压力。然而，由于目前可用的单态氧发生器在低压下操作，因此不能提高引入混合室的氧气流的停滞压力。另一方面，碘流可以被提升到更高的压力。通过将高压碘流与低压氧流混合，可以提高增益介质的总压。为了做到这一点，而不引起冲击波或其他不良影响，碘流应充分扩大，使两股流的压力匹配， ...更多信息 n他们加入。换句话说，具有较高马赫数的碘流应该与具有较低马赫数的氧流混合。因此，在这项研究中，具有不同的马赫数的两个流动之间的混合特性进行了数值研究。本文采用了一个带斜板喷管阵列的超音速平行混合系统，研究了三种喷管，即（a）斜板喷管、（B）对称斜板喷管和（c）对称后掠斜板喷管。每个喷嘴阵列具有不均匀堆积的形状，目的是引起涡流并增强混合。氧和碘在喷管中分别膨胀：在低的滞止压力下，单重态δ氧流加速到单位马赫数，而在高的滞止压力下，碘流被氮稀释后加速到较高的马赫数（= 4.8）。通过对等效一维流动的分析，确定了喷嘴尺寸和压力室条件，并对不同马赫数的氧碘混合特性进行了数值研究，旨在提高超音速流氧碘激光器排气的压力恢复。计算了斜板喷管、对称斜板喷管和对称后掠斜板喷管的流场。结果表明，对称后掠斜坡喷管比其他两种喷管具有更高的增益和可忽略的低排气压力。少

One of the hindrances in industrial applications of supersonic-flow chemical oxygen-iodine laser (S-COIL) is the lowness of the exhaust gas pressure, due to which a massive pressure-recovery system is required to implement the discharge of the spent working mixture. In order to downsize the system, the stagnation pressure of the exhaust gas should be improved by means of utilizing an active oxygen-iodine gain medium at a higher total-pressure. However, the stagnation pressure of the oxygen flow, which is introduced to the mixing chamber, cannot be raised since singlet oxygen generators available today operate at a low pressure. The iodine flow, on the other hand, can be boosted to higher pressure. By mixing this high-pressured iodine flow with the low-pressured oxygen flow, we can raise the total pressure of the gain medium. In order to do this without causing shockwave or other undesirable effects, the iodine flow should be expanded enough so that the pressures of both flows match whe … More n they join. In other words, the iodine flow having higher Mach number should be mixed with the oxygen flow having lower Mach number. Thus, in this study, the mixing characteristics between two flows having different Mach numbers are numerically examined. A supersonic, parallel mixing system with ramp nozzle array is adopted.Three types of nozzles, namely, (a) ramp nozzle, (b) symmetric ramp nozzle, and (c) symmetric swept-ramp nozzle are examined. Each of the nozzle arrays has an unevenly-piled shape with the intention of causing vortex and enhancing mixing. The two flows of oxygen and iodine expand separately in the nozzle : The flow of singlet-delta oxygen at a low stagnation pressure accelerates to unit Mach number, while the flow of iodine, which is diluted with nitrogen, at high stagnation pressure does to a higher Mach number (= 4.8). The nozzle dimensions and plenum conditions of the flows are determined based on the examination of an equivalent one-dimensional flow.The characteristics of mixing between two flows of oxygen and iodine, having different Mach numbers, are numerically examined with the intention of improving the pressure recovery of the exhaust gas of supersonic-flow COIL. The flow fields are calculated for three types of nozzles, namely, ramp nozzle, symmetric ramp nozzle, and symmetric swept-ramp nozzle. The results indicate that the symmetric swept-ramp nozzle has significantly higher gain and negligibly lower exhaust gas pressure than other two. Less