一种对转涡轮性能基本分析

Basic analysis of a counter-rotating turbine

关键词:  航空发动机  对转涡轮+  效率  出功比+  速功比+

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

摘要:

借鉴Stewart关于对转涡轮的效率分析方法,从速度三角形基本分析入手,以速功比为主要变量,通过与一级高压一级无导叶低压涡轮对转涡轮的比较,考察一级高压两级低压第一级无导叶对转涡轮性能特点。研究表明:各转速比下,后者对转涡轮高效率对应的总速功比范围都比前者对转涡轮窄,但其高效区发生在更小的总速功比区域;随转速比绝对值增加,两种涡轮高效率区都增加,且其位置均偏向更大的总速功比区域;相比于前者对转涡轮,后者对转涡轮具有较低出功比,且偏向于低速功比区域;随转速比绝对值增加,两种对转涡轮出功比范围均拓展。

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.