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Legislative requirements to reduce CO2 emissions by 2020 have resulted in significant efforts by car manufacturers to explore various methods of pollution abatement. One of the most effective ways found so far is by shortening the cylinder stroke and downsizing the engine. This new engine then needs to be boosted, or turbocharged, to create the full and original load torque. Turbocharging has been and will continue to be a key component to the new technologies that will make a positive difference in the next-generation engines of years to come. Concepts in Turbocharging for Improved Efficiency and Emissions Reduction explores the many ways that turbocharging will deliver concrete results in meeting the new realities of sustainable, green transportation.

In many automotive highway/off-highway engine cooling applications the fan has to provide a fairly large pressure rise and operate with a large gap between the tip of the blade and the shroud surface (tip clearance). This can pose difficult design challenges. This paper presents a design process coupling 3D inverse design with a Multi Objective Genetic Algorithm (MOGA) for an axial cooling fan. The aim is to reduce the leakage loss and profile losses to improve performance. The inverse design method parameterizes the 3D shape of the axial fan with a reduced number of design parameters allowing a larger exploration of the design space in the optimization process. The methodology is applied to the design of a highway truck engine cooling fan with a tip gap of 8% of blade height. Two designs from the optimization are analyzed in detail using 3D Computational Fluid Dynamic (CFD) simulations, confirming that the design optimized for minimizing leakage losses meets the design specification.