民航大涵道比涡扇发动机三大特性分析

摘要

The accurate steady-state model is the basis for the study of the three major characteristics of aero-engine.By the component characteristic modeling method,establish the steady-state model of civil aviation high Bypass-Ratio turbofan engine.The study found that When the flight altitude and Ma number remains constant,the thrust increases as the engine rotating speed increases,but at a high rotating speed,the thrust increases slowly.In the range of low rotating speed to middle rotating speed,the Specific Fuel Consumption (SFC) decreases with the increase of rotating speed;in the middle rotating speed to high rotating speed range,SFC increases with the increase of rotating speed.When the flight altitude and engine rotating speed is constant,the total thrust of the engine tends to decrease when the Ma number is increased,and the SFC increases sharply with the increase of the flight speed.When Ma number and the engine rotating speed remains constant,the thrust decreases as the height increases.At height range of 0-11Km,the SFC drops as the height increases,and the SFC remains the same after the height exceeds 11Km,but this is obtained without considering the Reynolds number correction;The low Reynolds number effect will cause the SFC of the engine to rise after 11Km.%准确的稳态模型是进行航空发动机三大特性研究的基础,采用部件特性建模方法,建立了民航大涵道比涡扇发动机的稳态模型;研究发现,保持飞行高度,马赫数不变时,增加发动机转速时,推力一直增加,但到了高转速阶段,推力的增加速度变缓;在低转速到中转速的区间内,燃油消耗率(SFC)随转速增加而降低;在中转速到高转速区间内,SFC随转速增加而增加;保持飞行高度,发动机转速不变时,增加马赫数时,发动机的总推力呈下降趋势,燃油消耗率随飞行速度增加而急剧增加.保持飞行马赫数,发动机转速不变时,推力随着高度的增加而降低;在0～11 km时,随着高度增加SFC一直下降,高度超过11 km后,SFC也保持不变,但这是不考虑雷诺数修正的情况下得到的;低雷诺数效应会导致11 km以后发动机的SFC会有所上升.