微小发动机甩油盘最小适用直径研究

Research on Minimum Applicable Diameter of Slinger Used in Micro Turbojet

航空发动机对尺寸有严格限制,甩油盘直径越大,雾化效果越好。针对甩油盘在发动机启动、慢车及高海拔地区工作时雾化性能不足,对甩油盘的最小适用直径Dmin进行了理论研究。甩油盘在液柱破碎模式时雾化性能最好,研究得到了各转速下甩油盘处于液柱破碎模式时燃油流量的计算方法。不同流量对应的液雾索特尔平均直径(Sauter Mean Diameter, SMD)不同,根据燃油流量计算得到甩油盘液雾SMD的范围,并由此推导出满足发动机启动、慢车状态要求的甩油盘最小适用直径Dmin的计算公式。高海拔对甩油盘雾化有不利影响,研究得到了海拔H处,甩油盘最小适用直径DHmin的计算公式。某型发动机启动转速为6000r/min,慢车转速为20000r/min,当燃油为航空煤油RP-3时,经理论分析,得到地面甩油盘直径应大于7.77cm;高海拔4000m处,甩油盘直径应大于9.49cm。

Aircraft engines have a strict limit on size,and the atomization performance of the slinger is better with the greater diameter.The minimum applicable diameter of the slinger is studied for that the atomization performance of the slinger is inadequate when the engine is starting-up,idle running or working at high altitude.The atomization performance of the slinger is the best when the fuel leaves the slinger in ligament formation,and the calculation method of the fuel flow range is obtained when the slinger is in ligament formation at different rotational speed.The spray SMD is calculated according to the fuel flow rate,and the calculation formula of the minimum applicable diameter which meets the engine starting-up and idle running requirements is deduced.The high altitude has a negative effect on the slinger atomization,and the calculation formula of the minimum applicable diameter at the altitude H is deduced.A certain engine rotational speed is 6000r/min when starting-up and 20000r/min when idle running.If the fuel is RP-3,the diameter of the slinger which used on ground should be greater than 7.77cm through theoretical analysis.When works at an altitude of 4000m,the slinger diameter should be greater than 9.49cm.