RESEARCH PROGRESS ON LOW PRESSURE TURBINE INTERNAL FLOWS AND RELATED AERODYNAMIC DESIGN

With increasing interests on high altitude Unmanned Aerial Vehicles(UAVs),more and more atten- tions have been paid to the research of nero-engines under high altitude,low Reynolds number conditions.This paper reviews the research progress on complex internal flow in low Reynolds number and low pressure turbine (LPT)in recent years.The main topics include unsteady flow characteristics of LPT,mechanisms of separation and transition phenomena of boundary layer,mechanisms of periodic wake/boundary layer interactions.Based on flow mechanisms,an aerodynamic design method for low Reynolds number LPT is proposed.The interac- tions of wake/boundary layer can inhibit separations and diminish profile losses.Taking unsteady effects into account in the aerodynamic design,one can effectively improve blade loading or reduce aerodynamic losses, and finally improve the performance of LPT.The numerical and experimental results validate this aerodynamic design method.