Preliminary Design Concepts for High Solidity Nozzle-Less Radial Inflow Gas Turbine for Small Capacity Gas Turbine Engine

The present work for the design of nozzle-less radial inflow turbine begins with power requirement of 20 kW. Based on the available parameters like temperature, pressure and mass flow rate required for the design are obtained from cycle analysis initially preliminary design of rotor was developed and from the available loss models the efficiency of the turbine was found. After completion of the preliminary design of turbine, it was felt necessary to optimized the result for best efficiency accordingly an analytical study was undertaken to study the influence of different parameters like inlet absolute Mach number, relative exit Mach number, solidity, relative velocity ratio, hub to shroud radius ratio and rotational speed on efficiency. VISUAL BASIC program is developed to study the effect of different parameters on efficiency, for different speed conditions it can be observed that for same solidity and higher speed gives the compact size with less variation in losses and efficiency. The results obtained from analysis also suggest the value of higher solidity but in practical situation that will restrict the flow through runner that by increasing the losses and reducing the efficiency.Copyright © 2006 by ASME