ノズルスロート部上流におけるアークプラズマ気流の分光計測

Abstract

Flow near the sonic throat is spectroscopically measured to obtain the vibrational and rotational temperature in arc heated flow of pure Nitrogen. Arc heater experiments were conducted by using the Huels type arc heater. The B^2Σ2Σ^+_g transition of Δυ=0 of the N^2+ molecule, is referred in the region of 383 to 392 nm of the N^+_2+ 1st negative band system, and the C^3П_u-C^3П_g transition of Δυ=1 of the N_2 molecule, is referred in the region of 309 to 316 nm of the N_2 2nd positive band system. Spectra profiles in arc heated flow are obtained to estimate the vibrational temperature from the both bands at upstream of the nearly sonic throat. The vibrational temperatures T_υ are estimated to be about 2900～3200K from average inclination line close to (0, 0)-(2, 2) from the N^+_2(lst neg.), and about 3600～4300K from inclination line close to (1, 0)-(4, 3) from the N_2(2nd pos.). The average rotational temperatures in an arc heated flow are obtained from the N^+_2(lst neg.) bands, (0, 0) and (1, 1) of Δυ=0, and from the N_2(2nd pos.) bands, (1, 0) and (2, 1) of Δυ=1. The rotational temperatures T_r are estimated to be about 1600～1800K from 2<J'<26, and about 5900～7400K from 6<J'<42 of the rotational quantum number. While the ID stagnation temperature T_0 of the arc heated N_2 estimated by using 1D nozzle flow calculation, is about 2300～2500K.