Design of Nozzle-Less Radial Inflow Gas Turbine for Small Capacity (20 kW) Gas Turbine Engine

Abstract

In recent years, looking to the advantages of radial inflow gas turbine much research is focused in this area. The various applications like auxiliary drives in aircraft engine and automobile application where very high speed, compact size and greater specific power are the prime requirements, radial inflow is there by choice. The present work for the design of nozzle-less radial inflow turbine begins with power requirement of 20 kW, the parameters like temperature; pressure and mass flow rate required for the design are obtained from the detailed gas turbine cycle analysis. Based on the available data from cycle analysis initially preliminary design of rotor was developed, from the available loss models the efficiency of the turbine was found. The preliminary design provides the leading dimensions of the rotor with inlet and exit conditions. The objective of most designs will be to maximize the efficiency and/or to develop the compact size. 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 and hub to shroud radius ratio on efficiency. VISUAL BASIC program is developed to study the effect of different parameters on efficiency. From the detailed loss analysis the selection of these parameters can be made to achieve optimum performance. It is believed that present work will provide necessary guidelines for the optimal design of radial inflow gas turbine.