Heat exchanger integration with an aero-engine bypass duct

Abstract

The development of aero engines with geared fans may require the use of an air/oil heat exchanger (AOHE) embedded within the bypass duct to dissipate heat from the power gearbox of the fan. It is important that the AOHE system is designed and installed to minimise any detrimental impacts on exhaust performance while meeting the heat exchanger (HEX) heat transfer requirements. This paper introduces and demonstrates the capabilities of a coupled mixed fidelity method to model a naturally ventilated AOHE embedded within the bypass duct. The method is demonstrated in this paper by using it to explore and quantify the trade-offs between the HEX design and performance and the impact on the exhaust system. Overall, for the specific example considered, the introduction of the HEX could reduce the cruise thrust by 0.7% while meeting the required heat transfer at maximum take-off. Overall, the work shows how a mixed fidelity method can be used for preliminary design assessments of the integration of the HEX with the bypass duct.