CuRAX – a new concept of a velocity-compounded radial micro-turbine for waste heat recovery

Abstract

The paper introduces and discusses the new concept of a velocity-compounded, radial entry axial outlet Curtis turbine – called CuRAX. First, the motivation for the new turbine concept is discussed and the consideration which led to the CuRAX architecture is introduced. A 5 kWel air CuRAX turbine demonstrator was designed, following the in-house design procedure, and numerically and experimentally verified. The flow field shows the expected pressure and velocity distribution of a velocitycompounded turbine. However, potential for improvements is also obvious. The experimental results show the superiority of the CuRAX turbine at its design speed of 29,000 rpm with 50% total-to-static isentropic efficiency compared to 46 % of the quasi-impulse cantilever turbine – its direct competitor.