@techreport{oai:jaxa.repo.nii.ac.jp:00044989,
 author = {木皿, 且人 and 宮島, 博 and 阿部, 登 and 佐藤, 政裕 and 鎌田, 真 and 須藤, 孝幸 and 毛呂, 明夫 and 鳥井, 義弘 and KISARA, Katsuto and MIYAJIMA, Hiroshi and ABE, Noboru and SATO, Masahiro and KAMATA, Makoto and SUDO, Takayuki and MORO, Akio and TORII, Yoshihiro},
 month = {Aug},
 note = {The LE-5 engine, which will be installed in the second stage of Japan’s next launch vehicle, requires tank head ignition of the main thrust chamber and allows a small pressure budget to the igniter. Vacuum ignition tests of the original igniter revealed that its ignitability was marginal to the requirement. This experimental study was conducted to obtain information to improve the vacuum ignitability of the air-gap type torch igniter. Vacuum ignition tests of the modified igniters as well as the original igniter were conducted to obtain the minimum ignition pressure as a function of mixture ratio, i.e., lines of demarcation between the ignition and no-ignition regions in the preignition chamber pressure-mixture ratio plane. For the film cooled igniter, a marked reduction of the minimum ignition pressure was demonstrated by the combined effect of the following modifications:(1)locate the igniter throat just downstream of the film coolant injection ports, (2)reduce the throat diameter to half that of the original igniter, and (3)make 6 spikes on the otherwise circular cross section of the cathode, the spikes being in line with 6 fuel orifices. Of the above three modifications, the reduction of the throat diameter were shown to be the most effective in improving the vacuum ignitability. The minimun ignition pressure for different throat diameters was correlated well by the Reynolds number of oxygen flowing the annular cross section of the spark gap. Test results of a dump cooled igniter, photographic observations of the electric discharge over the annular gap, a discussion of the possible mechanism of a ignition failure, and the effect of an inadvertent solid particle contamination on the ignitability are also described., 資料番号: NALTR0732000, レポート番号: NAL TR-732},
 title = {液酸・液水ロケットエンジン用点火器の真空着火試験},
 year = {1982}
}