Performance adaptation of a 100 kW microturbine

Abstract

For design point and off-design performance analysis of a micro gas turbine, it is necessary to have characteristics of all components. In this paper, a method has been presented to estimate specifications of components for a 100 kWe single shaft variable speed microturbine. It has been developed two algorithms to obtain detail parameters of engine from available target parameters at design point (DP) and off-design (OD) conditions. DP adaptation algorithm contains some thermodynamic constraints. Intake mass flow rate, compressor and turbine pressure ratio and efficiency, turbine inlet temperature and electrical power are DP target parameters. To-be-adapted parameters at DP contain intake efficiency, recuperator and water heat exchanger effectiveness and pressure drop ratio, and efficiency and pressure drop ratio of combustion chamber. Some target parameters like electrical power are kept constant and some others may have changes in DP adaption algorithm. After calculating all DP operating parameters of components, characteristic equations for compressor and turbine have been presented instead of scaling method. Compressor and turbine characteristics contain generally second order algebraic equations. OD target parameter was electrical efficiency for some rotation speeds. OD adaptation algorithm was adjusted to calculate optimum coefficients of characteristic equations by genetic algorithm.