Validation of a combined CFD/FEM methodology for the evaluation of thermal load acting on aluminum alloy pistons through hardness measurements in internal combustion engines
This work presents the results of amultidisciplinary research project, carried outin close collaboration with Ducati MotorHolding S.p.A., for the development of anintegrated methodology to design enginecomponents in aluminum alloy under highthermal loads. The results refer to the study ofan AA2618 (Al-Cu-Mg) alloy piston for highperformance motorcycle engines. The pistonhas been selected as the pilot component forthe development and validation of anadvanced Fluid Dynamics (CFD) and FiniteElement (FE) simulation methodology for theprediction of the inner thermal diffusion. Thesubsequent validation has been achievedthrough both the mechanical andmicrostructural characterization of thecomponent. The methodology here presentedconsists of close interaction between fluiddynamics(CFD) simulations of the combustionprocess and Finite Element (FEM) simulations ofthe thermal diffusion inside the components.Combustion is the main engine heat sourceand is simulated by means of a threedimensionalCFD code for reactive flows (FIREv2008-AVL), with the use of advancedcombustion (ECFM) and wall interactionmodels. The temperature map on the surfacesis based on the results of the iteration with FEMsimulation of thermal diffusion. The FEM modelused for the diffusion analysis receives theresults of combustion analysis as input. Twodifferent methods have been tested for thetransfer of the CFD thermal load to the FEMmodels: a) imposition on the piston crown of aspatial distribution of heat flux averaged overthe mean engine cycle; b) imposition on thepiston crown of both heat flux coefficients and..
