Paper 5: A Cycle Analysis Technique for Small Gas Turbines

Abstract

Aerothermodynamic analysis studies for open Brayton cycles are often conducted treating the component efficiencies as independent variables. However, as maximum output power is decreased and maximum cycle temperature increased, turbomachinery component sizes diminish resulting in lower component efficiencies. A meaningful small gas turbine cycle analysis should, therefore, treat the component efficiencies as dependent variables. A discussion of such a treatment, as employed during the cycle analysis phase of a small gas turbine, is presented. The particular aerodynamic configuration examined is one comprising a single-stage radial compressor and a single-stage radial turbine. Additionally, cycle performance charts for the selected configuration are presented indicating optimum cycle parameter combinations, attainable performance levels, and typical small gas turbine engine weights.