Demonstrator for aircraft heat exchanger life prediction
DALI aims at validating a virtual testing approach so that design and test loop can be shortened and tests can be partly replaced, applied on the development of future generation of compact heat exchangers, for the engine innovative bleed system; with higher requirements and thus damage probability. DALI proposes a fully integrated modelling platform where damage laws will be integrated relying on a multiphysics and multilevel modelling approach. A robust and reliable solution will be implemented based on an improved understanding of specific phenomena occurring during thermo mechanical ageing of heat exchanger in aircraft. The mainstream will enable to reproduce the thermal cycling ageing and its statistical probability by multiphysics simulations, and a set of master datasheets of fatigue curves and damage laws Manufacturing variability (local deformations, initial stress state), and other design variables will be included. The proposed validation scheme includes a set of details of increasing complexity where the simulation approach and the instrumented physical testing will be compared, and iteratively improved, so that real observations of cracking coming from Aircraft exploitation can be predicted. A representative coupon test plan and an innovative measurement to detect cracks initiation in non visible areas will be included. The prediction capacity will allow mastering the heat exchanger behaviour and the mean-time-between-failures, MTBF, to tailor the heat exchanger design, including sensitivity analysis for potential optimization. DALI stands on members’ skills and their cross advanced FEM knowledge capacities to enable a seamless technical coordination through the combination of customized experimental validation and advanced simulation so that a) an accelerated test approach can be implemented for in service life assurance, b) a degradation law that could be used in combination with a simplified and accurate simulations for future CHX precooler sizing.