Evaluation of nozzle configuration impact on flow structures and performance in Tesla turbine

Abstract

Momentum diffusion and kinetic energy transfer play crucial roles in turbomachinery. The Tesla turbine is a radial turbine that operates based on energy transfer between the operating flow and corotating disks. It has applications in various energy systems, such as the Organic Rankine Cycle and combined heat and power systems. Design parameters, particularly the nozzle configuration, significantly impact turbine performance. This study investigates two nozzle supply designs: one-to-many, where the nozzle provides fluid to all gaps, and one-to-one, with the individual nozzle for each gap. To minimize computational costs, only a portion of the entire domain is examined, and flow structures and their effects on Tesla turbine performance are analyzed. Large Eddy Simulation (LES) employing the Smagorinsky subgrid-scale model is used for flow simulation, enabling a comparison of flow structures, fluctuations, parameters, and their impact on system performance. The one-to-many configuration demonstrates lower efficiency with considerably higher fluctuations. The main source of these fluctuations is found to be the interaction of the inlet jet with the disk tips. In the one-to-one configuration, the source of the fluctuations is the rotating disks, with a different trend of distribution along the gap compared to the one-to-many configuration.