Linear model of a closed three-shaft Brayton cycle

Abstract

A linear model of a closed three-shaft Brayton cycle is developed. The model is intended to give an understanding of the dominant dynamic behavior in a nuclear power system that utilizes a closed three-shaft Brayton cycle. The insights gained from the model can be used for system design as well as for the design of control algorithms [S.T. Glad et al. (2001)] [B.Hendrisson et al., (2001)]. Linear models of the turbines and compressors are developed, followed by models of the shafts and the volumes inside the circuit. Thereafter, the system equations are derived from the component models and put into state space format. Finally, a time domain comparison is made between the linear system model and the responses predicted by the thermal-fluid analysis software program, Flownex