关键词: 航空发动机;对转涡轮+;效率;出功比+;速功比+

Abstract: Using Stewart’s method for reference and on the basis of analysis of velocity triangle,performance and range of application of a vaneless counter-rotating turbines(VCRT) which consists of a high pressure stage,two low pressure stages without guiole vane in one of them are studied through comparison with other VCRT in terms of work speed ratio.In all ranges of shaft speed ratio,range of total work speed ratio at high efficiency region of this VCRT is narrower than that of other VCRT which consists of a high pressure stage and low one without guide vane;however,the high efficiency region of this VCRT is always located in range of lower work speed ratio.In addition,this VCRT has a lower shaft work ratio,and can provide much more work.Shaft speed ratio(high pressure shaft and low pressure shaft) also exerts great influences on the efficiency and the application range of these two types of VCRT.As the absolute value of shaft speed ratio increases,high efficiency region always moves to the region with a higher total work speed ratio,and the shaft work ratio will also increase.

Key words: Aircraft engine;Counter-rotating turbine+;Efficiency;Specific work ratio+;Work speed ratio+