Quantitative Study of Flow Characteristics During Ignition for High Power Arc Heater
-
摘要: 电弧等离子体是通过电极之间击穿放电，产生热电弧，实现对冷态介质加热，目前大功率的电弧等离子体发生器在航空航天领域有重要的应用，是国内外开展飞行器防热材料筛选和考核研究最重要的地面模拟试验设备.本研究基于发展的高焓气流非接触式光谱诊断方法，开展对10 MW量级大功率长分段电弧加热器起弧过程流场特性的定量、定性研究，在线测量等离子气流的辐射光谱，并获得了等离子体气流电子温度和电极烧蚀铜原子摩尔组分浓度的测量结果.研究结果表明：起弧开始阶段，纯氩气通入，等离子体辐射光谱以分立的氩原子谱线为主；过渡阶段，随着空气的通入出现了N2和N2+的连续分子谱和Ar、N、O原子谱，等离子体电子温度随之降低；正式运行阶段，纯空气介质运行，辐射光谱以N2和N2+连续分子谱和N、O原子谱为主.整个电弧加热器起弧过程伴随持续的电极烧蚀，等离子体辐射光谱中铜原子谱线一直存在.氩气起弧时，等离子体气流电子温度稳定在11 000 K±300 K，显示出电弧加热器稳定的起弧特性.同时，电弧等离子体气流中铜原子摩尔组分浓度在（1~25）×10-6之间周期性变化，显示弧根旋转过程中不规则的电极烧蚀变化.发展的发射光谱诊断方法为研究电弧加热器真空氩气起弧特性提供量化手段，可以为真空-常压氩气起弧试验技术的发展和电极优化提供直接量化依据，为大功率常压叠片电弧加热试验平台发展奠定基础.Abstract: Arc-heated plasma generates thermal arc by breakdown discharge between electrodes to heat cold test medium. The high-power arc heater is the most important ground test facility to evaluate thermal protection system for hypersonic vehicles. Based on the developed non-intrusive spectroscopic methods, a study was carried out for quantitative and qualitative research on the ignition characteristics of the arc plasma for a 10 MW high-power long-segmented arc heater in this paper. In situ measurements were conducted to obtain the spectrum of the plasma flow, and the gas temperature and copper concentration by electrode erosion were measured to analyze the flow characteristics. The results demonstrate that: at the beginning stage of arc ignition, pure argon is injected and the spectrum of the plasma flow is mainly composed of the isolated spectrum of argon atoms; at the transition stage, there exist continuous molecular spectrum of N2 and N2+ and atomic spectrum of Ar, N, O when test medium of air is added into the arc heater, with the decrease of plasma electron temperature; at the normal operation stage with pure air operation for the plasma, the spectrum consists of N2 and N2+ continuous molecular spectrum and N, O atomic spectrum. In the whole ignition process, electrode erosion is observed from obvious copper atomic lines in the measured spectrum. When the argon arc plasma is operated, the electron temperature is stabilized at 11 000 K±300 K, indicating steady ignition characteristics for the arc heater. Meanwhile, mole fraction of the copper concentration periodically changes between (1~25)×10-6 during ignition, which shows the irregular electrode erosion owing to rotation of the arc root. This diagnostic method of emission spectroscopy developed in this paper provides a quantitative means for studying the characteristics of the vacuum argon ignition process, which can provide a direct quantitative basis for the development of vacuum- atmospheric pressure ignition for argon plasma and electrode optimization, and lay the foundation for the development of atmospheric pressure ignition for high-power segmented arc-heated test facility.
-
图 3 铜原子和氩原子配分函数随温度变化趋势
Figure 3. Partition functions of copper and argon under different temperatures
图 4 长分段电弧风洞及发射光谱诊断系统示意图
Figure 4. Schematic of the experimental setup of the long-segmented arc-heated wind tunnel and OES system
图 7 空气等离子体下典型组分光谱辐射强度随时间变化
Figure 7. Time-resolved variation of spectral intensity of selected species transitions for air plasma
图 8 氩气过程等离子体气流温度和浓度结果
Figure 8. Measured temperature and copper concentration of plasma flow during argon ignition
No. λ/nm E/eV gA×10-7/(cm-1) 1 696.54 13.33 1.92 2 706.72 13.30 1.90 3 738.40 13.30 4.24 4 801.48 13.09 4.64 5 922.45 13.17 2.52 6 965.78 12.91 1.63 
下载: 导出CSV
-
[1] Fridman A. Plasma chemistry[M]. Cambridge: Cambrid-ge University Press, 2008. [2] Marren D, Lu F. Advanced hypersonic test facilities[M]. Reston, Virginia: American Institute of Aeronautics and Astronautics, Inc., 2002. [3] Driver D M, Carballo J E, Beck R, et al. Arcjet testing in shear environment for mars science laboratory thermal protection system[J]. Journal of Spacecraft and Rockets, 2014, 51(4): 1151-1166. doi: 10.2514/1.A32728 [4] Horn D D, Bruce III W E, Felderman E J. Results and predictions for the new H3 arc heater at AEDC[R]. AIAA 96-2316, 1996. [5] Auweter-Kurtz M, et al. Measurement techniques for high enthalpy and plasma flows[R]. RTO-EN-8 AC/323(AVT) TP123, 2000. [6] Hanson R K, Spearrin R M, Goldenstein C S. Spectroscopy and optical diagnostics for gases[M]. Cham: Springer, 2016. [7] Esser B, Koch U, Gülhan A, et al. Results of the experimental study in the L2K facility[R]. DLR Report, 2011. [8] Vallon R, Soutadé J, Vérant J L, et al. A compact tunable diode laser absorption spectrometer to monitor CO2 at 2.7μm wavelength in hypersonic flows[J]. Sensors, 2010, 10(6): 6081-6091. doi: 10.3390/s100606081 [9] Johansen C T, Lincoln D A, Bathel B F, et al. Simultaneous nitric oxide/atomic oxygen laser-induced fluorescence in an arcjet facility[J]. Journal of Thermophysics and Heat Transfer, 2016, 30(4): 912-918. doi: 10.2514/1.T4691 [10] Kidd III F G, Narayanaswamy V, Danehy P M, et al. Characterization of the NASA langley arc heated scramjet test facility using NO PLIF[R]. AIAA 2014-2652, 2014. [11] Kim S, Jeffries J, Hanson R. Measurements of gas temperature in the arc-heater of a large scale arcjet facility using tunable diode laser absorption[R]. AIAA 2005-900, 2005. [12] Martin M N, Chang L S, Jeffries J B, et al. Monitoring temperature in high enthalpy arc-heated plasma flows using tunable diode laser absorption spectroscopy[R]. AIAA 2013-2761, 2013. [13] Kramida A, Ralchenko Y, Reader J, et al. NIST atomic spectra database(ver. 5.6.1)[EB/OL]. https://physics.nist.gov./asd. [14] Gordon S, McBride B J. Computer program for calcula-tion of complex chemical equilibrium compositions and applications[R]. NASA Reference Publication 1311, 1994. [15] 曾徽, 陈智铭, 闫宪翔, 等. 电弧加热器铜污染组分效应发射光谱定量研究[J]. 航空学报, 2020, 41(4): 123521. https://www.cnki.com.cn/Article/CJFDTOTAL-HKXB202004004.htmZeng H, Chen Z M, Yan X X, et al. Quantitative measurements of copper contamination in arc heater by using emission spectroscopy[J]. Acta Aeronautica et Astronau-tica Sinica, 2020, 41(4): 123521(in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-HKXB202004004.htm -
点击查看大图
图(8) / 表(2)
计量
- 文章访问数: 649
- HTML全文浏览量: 106
- PDF下载量: 19
- 被引次数: 0
邮件订阅
RSS