Experimental and Numerical Investigation of a Small-Scale Steam Turbine

This paper focuses on a small-scale radial steam turbine which is part of a fan-turbine unit (FTU) realizing the anode off-gas recirculation of a Solid Oxide Fuel Cell (SOFC). Due to the small size of the turbine (15mm diameter), it is not possible to determine its power by directly measuring the torque. Therefore, the performance parameters are evaluated using thermodynamics. However, heat transfers within the FTU have a non-negligible impact on the evaluation of the turbine power and total-to-total isentropic efficiency. New temperature and pressure measurements were thus conducted to refine the experimental results and the numerical model. The analysis of the experimental and numerical results highlights the significant influence of heat transfers, and provides a range for the turbine power and total-to-total isentropic efficiency, which are on the order of 34W and 39%, respectively. Furthermore, a heat investigation was carried out on the FTU in order to localise and determine the heat losses to the environment by using a simplified model. Through investigation, the primary source of heat loss was located at the turbine outlet.