Effects of wake-blade interaction upon aerodynamic performance of a turbine linear cascade Part 1: time-averaged aerodynamic performance

摘要

Detailed investigations are conducted on aerodynamic loss of a linear turbine cascade which is subjected to periodic wakes shed from moving bars of the wake generator. Parameters related to the wake, such as wake passing frequency (wake Strouhalnumber) or wake turbulence characteristics, are varied to see how these wake-related parameters affect the local loss distribution or mass-averaged loss coefficient of the turbine cascade. Effects of free-stream turbulence intensity are also examined. Inthe 1 st report of the present study a focus is placed on the measurements by use of a pneumatic five-hole yawmeter, which provides time-averaged stagnation pressure distributions and spanwise exit flow angle distributions downstream of the moving bars as well as of the turbine cascade. Experimental evidences obtained in this atudy reveal that the wake passage greatly affects not only the profile loss but secondary loss of the linear cascade. Noticeable change in the exit flow angle is also identified.