Influence of operational parameters on the performance of Tesla turbines: Experimental investigation of a small-scale turbine

Tesla turbines can be employed as small-scale turbines to recover waste energy in several industrial applications. However, there is no consensus on the turbine efficiency as experimental studies show significantly lower values than those obtained by analytical and CFD approaches. The present work addresses that question by performing a systematic literature review (SLR) on Tesla turbines, comparing the efficiency values reported by experimental and simulation works. To validate the SLR findings an experimental small-scale air driven Tesla turbine was built. The Design of Experiments (DoE) methodology was applied to understand the effects of selected independent variables on the turbine output power and mechanical efficiency. Inlet air pressure, temperature, and rotational speed were chosen as controllable factors of a Central Composite Design applied to the prototype of < 1 kW output power. The results indicate a 5% efficiency increase when inlet pressure increases 1 bar, on average. In the SLR, the average efficiency of 40%–60% was reported by simulation works, while experimental articles reported maximum efficiencies of 20%, on average. The experimental turbine analyzed in this paper presented a maximum efficiency of 14.2% ± 0.4% at 3 barg and 4,000 rpm, agreeing with other experimental studies.