Efficiency based optimization of a Tesla turbine

Abstract

Tesla turbine is a bladeless, radial turbine which might be suitable for the applications in various energy systems, e.g. in Organic Rankine Cycle or combined heat and power systems if its efficiency improves. The investigations presented in the paper concern efficiency based numerical optimization of a Tesla turbine. Parameters subjected to the optimization process are inlet nozzle height, inter-disc gap, nozzle angle, pressure and rotational velocity. The optimization was conducted using response surface methodology. The first stage of the optimization excluded pressure ratio as neutral to efficiency. The second stage of the optimization allowed determination of the most important parameters: tangential velocity ratio, partial admission coefficient, reaction degree and aspect ratio required for maximization of the turbine's efficiency. Efficiency was improved almost twice with the respect to the nominal model (from 9% to 17%) and validated experimentally. Performance characteristics of the optimized turbine model were calculated using computational fluid dynamics software.