Surface heat exchanger technology for tomorrow's fuel-efficient aero engines
Air-to-oil heat exchangers are an integral feature of advanced turbofan engine designs. By maintaining oil and fuel temperatures within defined limits, the surface cooler contributes to achieving optimal engine performance. The passage of cool bypass flow over the air-washed surface of the heat exchanger cools oil and fuel. However, current surface coolers are parasitic to the engine and also occupy surfaces that serve for abating engine noise. As such, their weight, volume and efficiency become critical issues. The EU-funded SHEFAE (Surface heat exchangers for aero-engines) project aimed at designing and manufacturing a metallic surface cooler that will replace a part of the core fairing structure. Project partners developed and demonstrated an advanced structural surface cooler attached on a mount composite structure (MCS). They defined specifications for both, and are in line with the requirements for modern gas turbine engines. The MCS' material capability, manufacturability and mechanical design challenges were addressed. This led to a better understanding overall, resulting in a competitive design that offers weight savings of 20 % over current state of the art. The design manufacture was successful with good quality parts being produced without delay thanks to computational process modelling of the manufacturing method. Scientists investigated the failure mechanisms for composite bolted joints under different operating conditions, and developed analysis models to predict such failures for wide-ranging circumstances. They evaluated the performance of various material resins under fire conditions and determined which one is best suited. The SHEFAE team also devised models to assess the performance of surface coolers. By introducing technology for civil aerospace applications in Europe and Japan, SHEFAE contributed to the highly ambitious goals of the European Vision for Aviation 2050. The project also strengthened the link between European and Japanese research and technology partners and industries.
Keywords
Surface heat exchanger, aero engines, surface coolers, SHEFAE, mount composite structure