Innovative Heat Exchanger Concepts
Targeting at a constant improvement of the efficiency of aero engines and a reduction of the gas pollutants and fuel consumption, alternative concepts in the overall design and operation of aero engines are constantly investigated. In the last 15 years, the Laboratory of Fluid Mechanics and Turbomachinery of Aristotle University of Thessaloniki, in close collaboration with MTU Aero Engines AG, has performed significant research activities focused on the optimization of aero engine recuperative technologies. Under this concept, a system of heat exchangers is integrated in the exhaust nozzle of the aero engine in order to exploit part of the thermal energy of the exhaust hot-gas and preheat the compressor discharge air before the latter enters the combustion chamber. This promising technology can significantly contribute to the reduction of specific fuel consumption, fuel burn and pollutant emissions leading to more efficient and environmentally friendly aero engines.
LFMT research activities were performed within the framework of major European Research projects (FP4-AEROHEX, FP5-NEWAC, FP6-LEMCOTEC, HORIZON 2020-ULTIMATE) and were primarily focused on the flow field and heat transfer investigation of the heat exchangers together with the thermodynamic analysis of the aero engine performance. These activities were supported by experimental measurements in dedicated test-rig facilities and detailed CFD computations for both the heat exchanger core geometry and the aero engine exhaust nozzle, and 0-D thermodynamic cycle analysis. Significant efforts were provided in order to optimize the design and integration of the heat exchangers system inside the aero engine nozzle installation together with the design of new heat exchanger concepts focusing primarily on the reduction of pressure losses and weight together with the optimization of the heat exchanger effectiveness.