A Test Facility for the Investigation of Steady and Unsteady Transonic Flows in Annular Cascades

Abstract

A unique non-rotating aerodynamic test facility is presented. It is designed for steady and unsteady transonic flow investigations in annular cascades. The fundamental advantage of this vehicle design, compared to a linear cascade facility, is the absence of boundary disturbances in the cascade and the self-adjustment of the flow periodicity. The downstream flow conditions can therefore be adjusted by the backpressure. The nozzle consists of a radial-axial section, in which spiral axisymetric flow is generated. With the adjustment of the total pressure and swirl angles in two separate distributors, a continuous variation of Mach number between 0<M<1,4 and flow angles between 12°<β<70° (from tangential) can be obtained. Further regulation of the flow quantities in the two separate distributors and boundary layer suction permits a continuous spanwise variation of the velocity and flow angle in the test section.