Analysis of cross-flow jet-type singlet oxygen generator

A cross-flow jet-type singlet oxygen generator has been developed, tested and analyzed in order to characterize the dependence of output performance on major input parameters. A thermal-balance model, which can predict O/sub 2/(/sup 1//spl Delta/) yield, gas temperature, and gas residence time, is proposed, and the resultant theoretical results are compared to the experimental data. Combined with computational fluid dynamics-based gas residence-time analysis, the model provides good agreement with the measured value of the O/sub 2/(/sup 1//spl Delta/) yield and the gas temperature. The surface chemistry model was applied to the measured Cl/sub 2/ utilization data, and was found to be inconsistent in the regime of high Cl/sub 2/ loading on the basic hydrogen peroxide jet, indicating that depletion of HO/sub 2//sup -/ is taking place.     

小功率连续波放电DF/HF化学激光器的功率

将SF6、O2、He3种可调气体预混合,喷入带有8个高压放电极的放电管,解离F离子,沿气流方向以亚音速喷入喉道,H2/D2由喉道上下喷入,光轴在H2/D2喷入下游1mm处。研究了连续波DF/HF激光器的多谱线输出功率与SF6、He和H2/D2的流量关系,以及混合气体中加入O2对激光器性能的影响。实现了HF最大输出功率12W,DF最大输出功率11W,连续可调,功率稳定,持续时间20min。     

脉冲氧碘化学激光放大器的理论模型

本文提出脉冲氧碘化学激光主振荡器加功率放大器(MOPA)系统中放大器的理论模型。计算表明:氧碘放大器内采用折迭光路方案,可以获得高的放大率及化学效率。     

氧碘化学激光束特性的检测

在氧碘化学激光器上测试激光束的特性,为进一步研究该激光器的“化学问题”和“光学问题”提供了一定的依据。     

放电引发脉冲氧碘化学激光器的研究

报道首次利用放电引发方法实现脉冲氧碘化学激光器的研究结果.证实低能电子也能很有效地引发氧碘激光反应.在O_2(~1(?))-CH_3I-N_2体系下激光能量输出达130mJ,电效率比光解方法高350倍.     

Mode locking of a CW supersonic chemical oxygen-iodine laser

This paper presents the results of the first mode-locking experiments on a supersonic chemical oxygen-iodine laser (COIL). Mode locking has been achieved using an acoustooptic modulator (AOM) and lasing demonstrated on the TEM₀₀ modes with a small intracavity aperture. A dc magnetic field was used to increase the number of axial modes and a peak power of 2.5 kW has been reached with a pulse width of 2.1 ns at a repetition rate of 43.68 MHz     

Magnetic modulation of gain in a chemical oxygen-iodine laser

A magnetic modulation of gain in a continuous-wave (CW) chemical oxygen-iodine laser (COIL) is proposed for several regimes of laser generation. The principle of the method proposed is based on a direct magnetic modulation of gain in the active zone of a COIL utilizing the Zeeman effect on the laser transition ²P_1/2 -²P_3/2 of iodine atoms. The possible applications of this technique to control the laser generation in COIL for technological purposes are outlined     

High-performance chemical oxygen-iodine laser using nitrogendiluent for commercial applications

A chemical oxygen-iodine laser (COIL), the VertiCOIL device, was transferred from the Air Force Research Laboratory (AFRL) to the University of Illinois at Urbana-Champaign (UIUC) and made operational. The performance of the high-power VertiCOIL laser was measured with nitrogen diluent, New nozzle designs were investigated and implemented to optimize nitrogen performance, Nitrogen diluent chemical efficiencies of 23% were achieved; these are the highest reported chemical efficiencies with room-temperature nitrogen diluent. A long duration, high chemical efficiency test was demonstrated with nitrogen diluent; a chemical efficiency of 18.545 at 30 mmol/s of chlorine was maintained for 35 min. The highest performance was obtained with new iodine injector blocks and a larger throat height. The new iodine injector blocks moved the injectors closer to the throat by 0.7 cm and the throat height was increased from 0.897 to 1.151 cm (0.353 to 0.453 in). The performance enhancements were in qualitative agreement with the system design predictions of the Blaze II chemical laser model. Three-dimensional computational fluid dynamics calculations using the general aerodynamic simulation program code confirmed the principle design change of moving the iodine injectors closer to throat     

Parametric study of a twisted aerosol-type singlet oxygen generator

A twisted aerosol singlet oxygen generator (TA-SOG), which is a new high-pressure SOG for the supersonic chemical oxygen-iodine laser (COIL), was developed. Its operational characteristics were compared to those of a conventional liquid-jet-type singlet oxygen generator. It was shown that TA-SOG is operated at an internal gas velocity of 85 m/s, which is three times higher than that of the jet-type SOG. Cl₂ utilization of 70% and singlet oxygen O₂ (¹Δ) yield of 85% were obtained under this condition. The results of our two-dimensional model calculation suggested that there must be some enhancement of a specific surface area in the reaction zone. The mechanism of this effect is discussed     

Supersonic chemical oxygen-iodine laser with X-shaped streamwise vortex Generator

High-throughput operation of a supersonic chemical oxygen-iodine laser (COIL) is achieved with an advanced mixing nozzle. The mixing nozzle consists of a staggered arrangement of thin wedges lying across the flow duct, and looks like the letter "X" when it is viewed from the side. A 32.9% chemical efficiency is measured experimentally with this nozzle and buffer-gas precooling. Computational fluid dynamics (CFD) calculations are conducted to understand the rapid mixing capability of the nozzle. A series of streamwise vortices generated by the alternating wedges greatly enhances the mixing process in the supersonic stream and the rapid formation of the gain medium. The temperature and Mach number of the flow field are estimated from the gain-profile measurement of the I (/sup 2/P/sub 1/2/) to I (/sup 2/P/sub 3/2/) transition. Good agreement with the CFD calculations is seen.     

High-efficiency operation of chemical oxygen-iodine laser usingnitrogen as buffer gas

High-efficiency operation of supersonic chemical oxygen-iodine laser (COIL) with an advanced jet-type singlet oxygen generator using nitrogen as buffer gas was demonstrated. Laser output was remarkably increased when buffer gas was cooled with liquid nitrogen. The effects of buffer gas temperature on the characteristics of the oxygen-iodine laser medium was discussed. A net chemical efficiency of 23.4% was obtained at 405 W when the chlorine molar flow rate was 19 mmol/s     

化学法生成碘原子应用于氧碘化学激光器的理论模拟

分析了化学法生成碘原子应用于COIL的优缺点,根据化学法生成碘原子的反应体系和氧碘化学激光器的反应机理建立了一维气体流动预混理论模型,从理论上研究了ClO2与NO反应生成Cl原子的产率随反应器压力的变化,加入HI的位置对生成I原子的影响,化学法生成碘原子代替碘分子注入到COIL中的小信号增益沿气流方向的变化,并与加入碘分子时进行了对比.     

小型单重态氧发生器中氯气利用率的测量

在一台为化学氧碘激光器而研制的小型射流式单重态氧发生器上建立了一套氯气利用率测量系统;从实验和理论两方面详细研究了光源线宽、气流温度、水气含量、气流组分对紫外吸光光度法测量氯气利用率的影响;测量结果和误差分析表明,在良好设计的实验中,氯气利用率的相对测量误差约为2%,主要来源于光电倍增管(PMT)的噪音.最后,提出了减少测量误差和扩大氯气利用率测量量程的方法.我们的工作将有助于更加准确地和精确地测量化学氧碘激光系统中的单重态氧发生器的氯气利用率.     

连续波化学氧碘激光器的小信号增益和腔内损耗

本文用变耦合率方法和平行板转动最大损耗法分别测出小信号增益为1.60×10~(-3)cm~(-1)和1.75×10~(-3)cm~(-1),腔内损耗为12.0％,获得了饱和参量为3.00kw/cm~2,并将所得结果与其它报道作了比较。     

电引发脉冲氧碘化学激光器的增益

本文对脉冲氧碘化学激光器的增益性能进行了理论估算。碘原子由CH_3I电离产生。研究了各种压力条件下成份比和CH_3I离解度对增益系数的影响。     

Output power stabilization of a chemical oxygen-iodine laser withan external magnetic field

Laser power stabilization for a chemical oxygen-iodine laser (COIL) was demonstrated using a complete feedback system with an external magnetic field based on the Zeeman effect of the iodine transition. The input/output characteristics of the feedback system are theoretically analyzed and found to be consistent with the experimental results. As a result, highly stable output power of less than 0.4% rms fluctuation was successfully obtained even in the presence of disturbance associated with mechanical vibration. It was also found that the response time of the system was as short as 1 ms limited by the applied voltage of the electromagnet     

Experimental study of gain and output coupling characteristics of aCW chemical oxygen-iodine laser

Gain and output coupling characteristics of the CW chemical oxygen-iodine laser (COIL) are determined experimentally by means of varying the output coupling method. Under the conditions that the Cl₂ flow rate is 11.8 mmol/s, the I₂ molar flow rate is from 20 to 50 μmol/s, and the duct pressure is 200 Pa, the following were obtained from the experimental data: maximum values of output power of 58 W, and optimal output coupling factor of 1.50%, a resonator efficiency of 4.8%, an unsaturated small-signal gain of 1.55×10^-3 cm^-1, a threshold small-signal gain of 1.31×10^-3 cm^-1, a saturation intensity of 1150 W/cm², intraresonator losses of 9%, and an atomic iodine concentration of 2.85×10¹⁴ cm^-3. A comparison of these results to the published data of other COIL systems is presented     

Operation of a small-scale CW deuterium fluoride chemical laser

We have investigated a small-scale continuous-wave DF chemical laser. Measurements are reported which indicate a multiline output power of 11 W using SF6as the fluorine source. With NF3used as the fluorine source, a multiline output power of more than 20 W was obtained. The degree of SF6dissociation was found to be about 13 percent with O2addition.     

Measurements of peak power enhancement and power conservation inmagnetically gain-modulated chemical oxygen-iodine laser

A periodically pulsed regime of the magnetically gain-switched chemical oxygen iodine laser was investigated. The effects of different magnetic field intensity and pulse length on the laser power pulse enhancement and the mean power conservation were studied experimentally     

A simplified analytic model for gain saturation and powerextraction in the flowing chemical oxygen-iodine laser

This paper describes the development of a simplified saturation model (SSM) for predicting power extraction from a chemical oxygen-iodine laser (COIL). Using the Fabry-Perot gain saturation assumption, analytic expressions for COIL extraction efficiency are presented for both constant-density and variable-density cavity conditions. The model treats mirror scattering, nonsaturable distributed losses, and diffractive losses from the mode-limiting aperture and is shown to be in excellent agreement with experimental COIL power extraction data. A comparison of the model with the Rigrod power extraction model is presented showing that the Rigrod model accurately predicts COIL extraction efficiency only in the limit that the COIL device no longer behaves as a transfer laser