Fully-coupled modeling and analysis of the influence of anti-icing bleed air system of engine inlet duct on compressor performance

A fully-coupled method that integrates the compressor, inlet duct and anti-icing bleed air system (AI-BAS) was established to offer a quick prediction of the effects of anti-icing bleeding on compressor performance, facilitating the development of a fully-coupled AI-BAS model and a thermodynamic cycle model for gas turbine engines. While the flow within the inlet duct was solved by 3-D numerical simulation, the AI-BAS was simulated by a reduced-order model and the thermodynamic performance of the compressor was estimated by a parallel-compressor method. Comparison with the results by the full-annular CFD simulation suggested that the proposed fully coupled method can adeptly predict the effects of inflow distortion on compressor performance. In this study, as the increase of anti-icing bleed air ratio, the distortion on AIP and the resulted performance degradation of compressor becomes obvious, especially the surge margin. In the fully coupled modeling with AI-BAS, both the bleed air ratio and temperature of discharged bleed air increase with the compressor pressure ratio. The variation of bleed air ratio reaches nearly 1 %. The compressor's operating point is observed to traverse among lines representing constant bleed air flow ratio, which cannot be captured by the classical bleed air model.