Developing a Computational Fluid Dynamics Model for Characterizing the Heat Transfer for a Cross-Flow Plate Heat Exchanger in a Boosted Diesel Engine

Abstract

<div class="section abstract"><div class="htmlview paragraph">In addition to the low cost and weight, the advantage of aluminum alloy heat exchangers over their counterparts is thanks to their anticorrosion, nonmagnetic, non-sparking, resilience, ductility at low temperature, high strength-to-weight ratio, high heat transfer coefficient, and easy fabrication. The advantages explain the currently popular utilization of aluminum alloy intercoolers in turbocharged engines. This study develops a finite volume simulation model using the computational fluid dynamics (CFD) available in the Fluent package to investigate the cooling efficiency for a cross-flow plate-fin intercooler system fabricated in this research. This is a cost-effective air-water heat exchanger made of thin aluminum alloy plates. The cross-flow plate-fin intercooler system was set up in this study using a perpendicular air-water configuration to cool down the hot air outlet from a turbocharger compressor equipped in a diesel engine. The engine with an intercooled turbocharger was tested in an AVL dynamometer testbed. The experiment results were used to validate the CFD model. An analysis was done for the heat transfer characteristic length, and 270 × 270 × 10 mm plates were selected to fit with the engine construction. The experiment was carried out for an eight-channel intercooler (four pairs of air and water channels) while the simulation model was developed only for two channels to reduce the computational cost. Numerical conversions were conducted to establish a model equivalent to the experimental one. The distributions of the inlet and outlet temperature, pressure, and velocity of intake air and coolant under various inlet water velocities and engine operating conditions were examined. This aims to optimize the heat transfer rate from water to air under engine-relevant operating conditions. The results show that the optimal cooling water velocity is 1.0 m/s corresponding with a flow rate of 1780 liter/hr. This approach could be useful to develop and/or optimize multichannel cross-flow plate heat exchangers for different applications including heat engines.</div></div>