Thermo-Mechanical Simulation of a Skin Heat Exchanger Considering Phase-Change Thermal Boundary Conditions

The progressive electrification of the regional aviation sector has put the focus on new thermal management systems that must be capable of evacuating around an order of magnitude more heat than current systems. The generated electrical power and the additional excess heat are estimated to be in the range of 300 to 1000 kW for short and medium range regional aircraft with hybrid propulsion systems. Typical values on current non-hybrid platforms are around 35 and 50 kW. In this context, TheMa4HERA project was launched to study different alternatives for thermal management of non-propulsive thermal sources. One of these new approaches makes use of Skin Heat Exchangers (SHX) where the ram air above the fuselage is used as a heat sink. After validating the thermal modelling in a simplified geometry with the inclusion of a condensation process in a previous work by the same authors, a complete thermo-mechanical simulation of a more detailed geometry is presented here. An analytical model is also provided which justifies the parallel-flow configuration selection. The temperature field obtained from the thermal simulation is imposed as a source of excitation to the mechanical model together with other realistic boundary conditions. Mechanical results have been compared with those obtained using the commercial code Ansys. The good matching obtained between codes (difference less than 10% in the maximum displacement and less than 5% for the worst stress) allows the validation of the thermal and mechanical solver interaction as well as generate new models that will be useful in later phases of the project when experimental measurements are available.