发动机加力外涵供油周期性摆动故障研究

Study on Engine Bypass Augmented-fuel Swing Periodically Fault

加力燃油控制品质对航空发动机的推力稳定和整机可靠性均有较大影响。某型发动机在地面台架试车过程中出现了加力外涵供油周期性摆动问题,对发动机安全和试车进度产生严重影响。采用故障树的方法对外涵控制回路中的控制参数、电液转换元件、计量活门、LVDT传感器等各个环节进行了逐一分析和验证,确认故障原因为计量活门LVDT传感器动、静子之间在运动过程摩擦力异常增大。改进加工工艺并对计量活门LVDT传感器进行了结构优化设计,新设计的传感器可在运动过程中减小摩擦力,在一定程度避免故障的重复发生。该LVDT传感器结构优化设计方案具有推广使用价值。

The quality of augmented-fuel control is very important to the stability of thrust and reliability of aeroengine. During a ground test of an aeroengine, the bypass augmented-fuel swung periodically, which had badly influence on test security and schedule. Failure tree analysis was used to solve the problem. Every factor in the control loop including control parameters, electro-hydraulic conversion element, fuel metering valve and line displacement sensor was analyzed and validated. The factor which caused the problem was finally found. The friction between fixed part and moving part of the line displacement sensor increased abnormity. As an improved design, the structure and manufacture technique were optimized. The new design can reduce friction and avoid similar problems. The design method deserves to be generalized.