A de-coupled approach to component high-fidelity analysis using computational fluid dynamics

Abstract

This study focuses on a simulation strategy that will allow the performance characteristics of an isolated gas turbine engine component, resolved from a detailed, high-fidelity analysis, to be transferred to an engine system analysis carried out at a lower level of resolution. The technique described in this paper is called ‘de-coupled’ high-fidelity analysis and utilizes an object-oriented, zero-dimensional gas turbine modelling and performance simulation system and a three-dimensional computational fluid dynamics (CFD) component model. The technique involves the generation of a component characteristic map without the parallel or iterative execution of the non-dimensional cycle and the three-dimensional CFD model. Therefore, a faster high-fidelity engine performance simulation can be achieved at run time. This paper demonstrates the ‘de-coupled’ approach to component high-fidelity analysis by using a three-dimensional CFD intake model of a high by-pass ratio turbofan as a case study. The CFD model is based on the geometry of the intake of the CFM56-5B2 engine. The CFD-generated performance map can fully define the characteristics of the intake at several operating conditions and power settings, and is subsequently used to provide a more accurate, physics-based estimate of intake performance (i.e. pressure recovery) and hence, engine performance, replacing the default, empirical values within the non-dimensional cycle model. A detailed comparison between the baseline engine performance (empirical pressure recovery) and the engine performance obtained after using the CFD-generated map is presented in this paper. The analysis carried out by this study demonstrates relative changes in the simulated engine performance > 1 per cent.