Models for the Prediction of Transients in Closed Regenerative Gas Turbine Cycles With Centrifugal Impellers

Abstract

This paper presents transient-flow component models for the prediction of the transient response of gas turbine cycles. The application is to predict the transient response of a small solar-powered regenerative gas-turbine engine with centrifugal impellers. The component sizes are similar to those under consideration for the solar-powered Space Station, but the models can easily be generalized for other applications with axial or mixed-flow turbomachinery. New component models for the prediction of the propagation of arbitrary transients in centrifugal impellers are developed. These are coupled with component models for the heat exchangers, receiver and radiator. The models are based on transient applications of the principles of conservation of mass, energy, and momentum. System transients driven by sinusoidal and double-step inputs in receiver salt temperature are presented and discussed. The new turbomachinery models and their coupling to the heat-exchanger models simulates disturbance-propagation in the components both upstream and downstream from the point of generation. This permits the study of the physical mechanisms of generation and propagation of higher-frequency contents in the response of the cycle.