A loss analysis based on experimental data for a 99.0 mm radial inflow nozzled turbine with different stator throat areas

Abstract

The results of experimental performance tests on a 99.0 mm radial inflow turbine with seven different nozzle throat areas were reported by the same authors in a previous publication (1). In order to perform a loss analysis, dividing the turbine losses between the stator and the rotor, a theoretical model of the stator loss was required. Several stator loss models were evaluated and the model described by Rohlik (9) was used as the basis for a loss analysis. Plots are given for the breakdown of losses at two operating speeds for each nozzle size. Both the stator and the rotor losses decreased markedly as the stator throat area increased towards a stator-rotor throat area ratio of 0.5. A significant step change in the magnitude of the rotor loss was evident at every stator size and appeared to correlate with the volumetric flowrate in the turbine exducer. Therefore a transition to a more efficient flow pattern in the exducer seemed to occur at higher flow-rates.