Rotational temperatures in nonequilibrium free jet expansion of nitrogen
Rotational temperatures in nonequilibrium free jet expansion of nitrogen
复制标题
氮气非平衡自由射流膨胀中的旋转温度
DOI：
10.1063/1.863041
复制
发表时间：
1980
影响因子：
4.6
通讯作者：
R. Cattolica
中科院分区：
文献类型：
--
作者：
D. Coe;F. Robben;L. Talbot;R. Cattolica
利用电子束荧光技术研究了氮气高超声速自由射流膨胀过程中的旋转不平衡现象。结果证实了先前研究的结论，即假设玻尔兹曼能量分布的偶极激发模型与实测线强度不一致。对这种差异进行了定量检验，发现与密度和源克努森数无关（除了密度大于1016 cm−3的数）。该效应归因于与喷射（电离）电子的相互作用，并且开发了一个新的激发模型，并显示与整个流动条件下的测量结果一致。将得到的旋转温度与简化的射流松弛模型进行比较，表明旋转碰撞次数为1.9。
Rotational nonequilibrium was investigated in hypersonic free jet expansions of nitrogen using the electron beam fluorescence technique. The results confirm the conclusion of previous investigations that a dipole excitation model, with an assumed Boltzmann energy distribution, is not consistent with the measured line intensities. This discrepancy was examined quantitatively and found to be independent of density and source Knudsen number (except at number densities greater than 1016 cm−3). The effect was attributed to interactions with the ejected (ionized) electron and a new excitation model was developed and shown to be consistent with the measurements throughout the flow conditions explored. The resulting rotational temperatures were compared to a simplified relaxation model of the jet and indicate a rotational collision number of 1.9.