@techreport{oai:jaxa.repo.nii.ac.jp:00044904, author = {田村, 洋 and 若松, 義男 and 鈴木, 昭夫 and 豊川, 光雄 and 小野, 文衛 and TAMURA, Hiroshi and WAKAMATSU, Yoshio and SUZUKI, Akio and TOYOKAWA, Mitsuo and ONO, Fumiei}, month = {Jan}, note = {The injection and combustion characteristics of unlike-impinging triplet injector for JP4 fuel and liquid-oxygen rocket combustor were studied. The injector element types considered were the OFO type, which consists of two outer oxidizer jets and one central fuel jet, and the FOF type, which consists of two fuel jets and one oxidizer jet. The spray characteristics of typical single elements of the two types were investigated through cold flow tests. Based on these tests, three multiple-element injectors (20 and 40 elements, 10 kN thrust at 2 MPa chamber pressure) were designed and fabricated, and were evaluated by means of cold flow tests and firing tests with combustion chambers of various lengths. The results were compared with a theoretical analysis based on a vaporization model. The conclusions of the study are as follows: 1)The design correlation of orifice area ratio for maximum mixing efficiency was confirmed for both OFO and FOF type elements. 2)The OFO element showed wider spray angles and relatively more uniform mixture ratio distributions than the FOF element. The spray characteristics of the single elements were sensitive to a change in mixture ratio. However, multiple element injectors were insensitive to such a change and showed substantially similar mixing measures, suggesting a marked averaging effect due to mixing with adjacent elements. 3)Since the statistical frequency of mixture ratio for multiple element injectors is approximately expressed by the logarithmic normal distribution function, the measure of mixing can be evaluated in terms of the logarithmic standard deviation or the dispersion, and Rupe’s mixing factor, Em, can be correlated with the mixing C efficiency. 4)Initial droplet diameters of the injectors at several mixture ratios were estimated from the comparison of the experimental performance with the theoretical analysis. The estimated diameters indicate that the vaporization of fuel is the rate controlling process. 5)OFO type injectors showed higher performances than FOF types; however, the former gave higher heat flux to the chamber wall. 6)Although direct ignition by a spark plug was used in the study, an injection of a small amount of nitrogen gas into the fuel line was remarkably effective in avoiding hard starts., 資料番号: NALTR0648000, レポート番号: NAL TR-648}, title = {Injection and Combustion Characteristics of Unlike-Impinging Triplet Injector for LOX-Kerosene Rocket Combustor}, year = {1981} }