蒸気エゼクタの性能特性について 植田 辰洋 一般社団法人日本機械学会 日本機械学會論文集 00290270 26 165 737 744 1960-05-25 Steam ejectors have several kinds of performance characteristics according to the outside conditions of ejectors-steam pressure at nozzle inlet, back pressure of diffuser and flow rate of entrained fluid. By the experimental studies on the flow state in ejectors, the following have been concluded. (1) The performance characteristics of ejector can be classified to basic three types-high vacuum, middle vacuum and low vacuum characteristics, or which the states at diffuser throat inlet are supersonic fulfilled flow, supersonic unfulfilled flow and subsonic flow, respective1y. (2) On the high vacuum characteristics, the pressure at mixing chamber takes the lowest value independently of the back pressure of diffuser, though the pressure is a variable of the back pressure in case of the middle vacuum and low vacuum characteristics. (3) Using the rectangular coordinates with respect to the back pressure of diffuser and the pressure at nozzle inlet, the existing ranges of these characteristics are divided by the straight lines through the point-the back pressure=0 and the pressure at nozzle inlet=0 abs. (4) On the high vacuum characteristics, the pressure at mixing chamber, the pressure at diffuser throat inlet and the highest back pressure of diffuser abtainable are respectively expressed by straight lines through the point-these pressures are 0 and the pressure at nozzle inlet is also 0 abs.-against the pressure at nozzle inlet. (5) The middle vacuum characteristics can not exist when the exit area of nozzle is made too large. The high vacuum characteristics disappear when the distance between nozzle and diffuser is increased. 1960-05-25 110002351186 AN00187419 9150575 JPN NDL NII-ELS Journal@rchive 3 On the Performance Characteristics of Steam Ejectors UEDA Tatuhiro The Japan Society of Mechanical Engineers Transactions of the Japan Society of Mechanical Engineers Steam ejectors have several kinds of performance characteristics according to the outside conditions of ejectors-steam pressure at nozzle inlet, back pressure of diffuser and flow rate of entrained fluid. By the experimental studies on the flow state in ejectors, the following have been concluded. (1) The performance characteristics of ejector can be classified to basic three types-high vacuum, middle vacuum and low vacuum characteristics, or which the states at diffuser throat inlet are supersonic fulfilled flow, supersonic unfulfilled flow and subsonic flow, respective1y. (2) On the high vacuum characteristics, the pressure at mixing chamber takes the lowest value independently of the back pressure of diffuser, though the pressure is a variable of the back pressure in case of the middle vacuum and low vacuum characteristics. (3) Using the rectangular coordinates with respect to the back pressure of diffuser and the pressure at nozzle inlet, the existing ranges of these characteristics are divided by the straight lines through the point-the back pressure=0 and the pressure at nozzle inlet=0 abs. (4) On the high vacuum characteristics, the pressure at mixing chamber, the pressure at diffuser throat inlet and the highest back pressure of diffuser abtainable are respectively expressed by straight lines through the point-these pressures are 0 and the pressure at nozzle inlet is also 0 abs.-against the pressure at nozzle inlet. (5) The middle vacuum characteristics can not exist when the exit area of nozzle is made too large. The high vacuum characteristics disappear when the distance between nozzle and diffuser is increased. 植田 辰洋 UEDA Tatuhiro 東京大学工学部