Axial Bladeless Turbine Suitable for High Supersonic Flows

Abstract

The development of future propulsion systems may rely on the extraction of power from high supersonic flows. In conventional supersonic turbines operating under such extreme flow conditions, the presence of blades induces important flow perturbations that result in severe aerodynamic losses and restrictions in the operating range, seriously affected by starting issues. These limitations present design opportunities for a bladeless turbine configuration. The present paper documents, for the first time in literature, an axial bladeless turbine concept, which is able to extract mechanical power from high supersonic flows through an annular channel. The tangential drag force exerted on the rotating inner and outer end-walls produces power, together with enhanced simplicity, coolability, and maintainability. Reynolds-averaged Navier–Stokes simulations allowed the detailed evaluation of the aerodynamic performance of the bladeless configuration. This unconventional axial turbine concept becomes a design choice for extracting power from supersonic flows, with minimum pressure losses.