One-dimensional model analysis and performance assessment of Tesla turbine

Tesla turbine is characterized by the bladeless design that makes it easy to be manufactured and operated. It offers an attractive option for power output in small and micro scale systems if an efficient design can be achieved. One-dimensional model is useful as it can adequately represent the flow characteristics in the Tesla turbine and allow parametric exploration for early design analysis. This paper improves the one-dimensional model for Tesla turbine. The limit expansion ratio of the nozzle is introduced, which is related to the geometry angle and the working fluid properties. The flow loss in the nozzle is evaluated instead of assuming an empirical velocity coefficient. The flow is regarded as turbulence rather than laminar, and friction factor is determined by the Reynolds number based on Moody Figure. In the rotor, the governing equations for compressible flow between adjacent discs are used. In addition, the radial pressure gradient effect in the rotor gap spacing is considered. The improved model show better agreement with the experimental data than the original model. The flow characteristics in the Tesla turbine is analyzed and the streamline of the bulk flow in the rotor is derived based on the one-dimensional model. Tesla turbine can yield considerable efficiency and it can be regarded as a potential choice to be applied in small and micro scale systems.