Session: 01-04 Engine Performance and Cycle Design II

Paper Number: 151647

Dynamic Response of Turbofan Engine in the Event of Shaft Failure: Fan and Compressor Operating Points and Turbine Overspeed Analysis 

A physics-based model has been developed to investigate the dynamic response of aero-engine in the event of low-pressure shaft (LPS) and high-pressure shaft (HPS) failure. The mechanism of the dynamic response of aero-engine before any compressor stall in the event of shaft failure is first discussed and analysed. The results show that the shaft failure essentially has a great impact on the functional integrity of aero-engines, therefore, the working points of the fan and compressors all deviate from the steady-state lines, the speed of turbine which loses load increase rapidly. Meanwhile, the fan/compressor, which is affected by the shaft failure but itself still connected to the turbine via the shaft, attempts to achieve a new power balance with the turbine. After HPS failure, the rapid decrease in core mass flow causes the working point of LPC to move rapidly to the left and traverse the surge boundary. In order to investigate and analyze the dynamic response of an aero-engine after LPC stall, the CLM is endowed with the volume dynamic effect, full-flow characteristics and flameout characteristics. The results show that the stalled LPC, where severe blockage occurs, together with the HPC losing drive, exacerbates the degradation of the aero-engine performance, causing the total mass flow and pressure ratio decreases rapidly. However, the HPC does not stall for a long time, although the core mass flow decreases rapidly due to the LPC stall, which is mainly due to the rapidly decreasing speed somehow coordinating with the reduced core mass flow. The combustor flameout caused by the high fuel-air ratio makes the HPT inlet temperature slightly lower. In summary, the LPC stall and combustor flameout, which affects the average angular acceleration of HPT by affecting the power of HPT, is actually beneficial to prevent HPT from overspeed or even disc burst resulted by HPS failure.

Presenting Author: Yuxi Guan Civil Aviation University of China

Presenting Author Biography: A phd student of Civil Aviation University of China

Authors:

Yuxi Guan Civil Aviation University of China
Shuai Liu Civil Aviation University of China
Jie Bai Civil Aviation University of China