Strategies for Performance Enhancement of Tesla Turbines for Combined Heat and Power Applications

Abstract

A small, efficient, and robust turbine is essential to the development of a small-scale (∼10 kWe) Combined Heat and Power (CHP) Rankine cycle system. While the Tesla turbine design offers a versatile solution with a low manufacturing and maintenance cost, its successful use in systems of this type hinges on development of a design that also offers high energy conversion efficiency. The investigation summarized here explored the parametric trends in Tesla turbine efficiency using model analysis of the turbine performance in tandem with experimental testing of a small scale Tesla turbine. The experimental data were used to evaluate the accuracy of trends predicted by the model analysis. Results of this evaluation show agreement between calculated and experiential efficiency. To further test the model, several non-dimensional parameters that arise from the model analysis were used to predict design modifications to the existing turbine that would improve turbine performance. Several of these modifications were fabricated and tested. Results show that the model is able to accurately predict efficiency variations that result from changes in turbine design. The model is then used to project new turbine designs that will maximize the efficiency of the turbine and recommendations are made for further improving Tesla turbine efficiency. Lastly, improved Tesla turbine designs are discussed in terms of their appropriateness for use in CHP Rankine cycle systems.