GRETA - An open-source generic research turbofan low-pressure compressor model

A Generic Research Turbofan (GReTa) low-pressure compressor (LPC) model is introduced and made freely available to the community. The model comprises a fan stage and a four-stage booster with a pressure ratio of ∼1.6 each. GReTa was inspired by the Energy Efficient Engine (E3), and the design work was carried out using limited data in the public domain for the E3 and similar engines. First, a thermodynamic model of the engine was created to establish the design objectives. Subsequently, a detailed compressor design was developed and extensively characterised using Computational Fluid Dynamics (CFD) analysis. The fan stage performance surpassed the original design objectives, and the integrated low-pressure compressor demonstrated acceptable performance across the design envelope. It was concluded that the model sufficiently resembles the features of a modern civil turbofan and can be used as a benchmark geometry for cross-comparison of computational codes at the tested conditions. The availability of an open turbofan compressor validation benchmark in a highly restrictive sector is paramount to further advancing computational methods used for engine design verification and validation, leading to certification by analysis. This includes several aspects pertinent to engine safety, such as operation in adverse atmospheric conditions and close to operating limits, compressor fouling and erosion, as well as virtual prototyping of feasibility studies of novel cycles and engine architectures.