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Micro-scale Analysis of Non-equilibrium Phenomena in Highly Rarefied Gas Flows

高度稀薄气流中非平衡现象的微观分析

基本信息

批准号：
13450072
负责人：
NIIMI Tomohide
金额：
$ 10.11万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

In this study, we develop the experimental system for 2R+2 N_2-REMPI and apply it to measurement of rotational temperature in a supersonic free molecular nitrogen flow. In the 2R+2 N_2-REMPI technique, nitrogen molecules are ionized, the nitrogen ions are detected as a signal and its spectra depending on the wavelength of an irradiated laser beam are analyzed to measure the rotational temperature through the Boltzmann plot. However, it is found from the experimental results that the number of molecules in the rotational states is not given by the Boltzmann distribution at the measurement point, showing the so-called non-Boltzmann distribution. Now, we are carrying out experiments changing the source pressure and the measurement point as parameters, to clarify the transition from the equilibrium to non-equilibrium in the rotational mode and to obtain the functional form of the non-Boltzmann distribution.The pressure range of Pressure sensitive paints (PSP) has been limited above 1 Torr (133.3 Pa) and there is no application to lower pressure range because the pressure sensitivity seems to be not so high in that range. In this study, we apply three types of PSP to the rarefied gas flow mainly lower than 1 Torr and examine those fundamental property, such as pressure/temperature sensitivity and time decay of luminescence and so on. Both PtTFPP/poly(TMSP) and Bath-Ru/AA have high sensitivity in the range of pressure lower than 1 Torr. Since the absolute luminescence intensity of PtTFPP/poly(TMSP) is higher than that of Bath-Ru/AA, however, it may better to use the former, judging from a point of S/N.Using laser induced fluorescence (LIF) of NO seeded in the carrier gas N_2 and a pressure sensitive paint [PtTFPP/poly(TMSP)], we visualize and analyze the flow field structures around the linear-type aerospike nozzle and the complicated pressure distribution on the spike surface successfully.

本研究发展了2 R +2N_2-REMPI实验系统，并将其应用于超声速自由氮分子流中旋转温度的测量。在2 R +2N_2-REMPI技术中，氮分子被电离，氮离子作为信号被探测，通过分析其随激光波长变化的光谱，利用玻尔兹曼曲线测量转动温度。然而，从实验结果中发现，在测量点处，处于转动状态的分子的数量不是由玻尔兹曼分布给出的，显示出所谓的非玻尔兹曼分布。现在，我们正在进行改变源压力和测量点作为参数的实验，阐明了转动模从平衡态到非平衡态的转变，并得到了非玻尔兹曼分布的函数形式。压敏漆（PSP）的压力范围被限制在1 Torr以上（133.3 Pa），并且不适用于较低的压力范围，因为在该范围内压力灵敏度似乎不那么高。本研究中，我们将三种类型的PSP应用到主要低于1 Torr的稀薄气体流中，并研究了它们的基本特性，如压力/温度灵敏度和发光的时间衰减等，PtTFPP/poly（TMSP）和Pt-Ru/AA在低于1 Torr的压力范围内都具有很高的灵敏度。由于PtTFPP/poly（TMSP）的绝对发光强度比PtTFPP/poly（TMSP）高，但从S/N的角度来看，PtTFPP/poly（TMSP）的绝对发光强度比PtTFPP/Ru/AA的绝对发光强度高。成功地可视化和分析了线型塞式喷管的流场结构和塞体表面复杂的压力分布。