Gas Turbine Transient Performance Simulation With Simplified Heat Soakage Model

Abstract

Abstract Reliable transient performance is crucial in handling an aircraft gas turbine engine from one steady state to another. The assessment of transient performance stability is normally done during the detailed design stage when component design details become available. Consequently, design iterations may be necessary and costly if engine transient handling and stability are not satisfactory. To make engine design more cost and time effective, it has become important to assess the transient performance stability at conceptual and preliminary design stage with the inclusion of key impact factors such as fuel control schedule, rotor dynamics and heat soakage. However, due to lack of detailed engine structural and geometrical information at the initial design stage, such transient performance simulation and assessment may have to ignore heat soakage effect. In this paper, a novel generically simplified heat soakage model for three major gas path components of gas turbine engines including compressors, turbines and combustors has been introduced to support more realistic transient performance simulation of gas turbine engines at conceptual and preliminary design stage. Such heat soakage model only requires thermodynamic design parameters as input, which is normally available during such design stages. The model has been implemented into in-house transient performance simulation software and applied to a model twin-spool turbojet engine to test its effectiveness. A comparison between transient performance simulated with and without the heat soakage effects demonstrate that the results are promising. Although the introduced heat soakage model is less accurate than that using detailed component geometrical information, it is able to include the major heat soakage effect in transient performance simulation and provide engine transient stability analysis to support conceptual and preliminary engine designs.