Gas Turbine Transient Performance Simulation With Simplified Heat Soakage Model

Reliable transient performance is crucial in handling an aircraft gas turbine engine from one steady state to another, especially during its acceleration and deceleration processes. The assessment of transient performance stability is normally done during 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 more and more 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, rotordynamics and heat soakage. However, due to lack of detailed engine structural and geometrical information at initial design stage, such transient performance simulation and assessment have been difficult. 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 transient performance simulation of gas turbine engines. Such heat soakage model only requires thermodynamic design parameters as input, which are normally available during conceptual and preliminary design stages of the engines. 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 those using detailed component geometrical information, it is able to initially assess the impact of heat soakage effect and provide engine transient stability analysis to support conceptual and preliminary engine designs.