The paper describes the effects of heat transfer enhancement and gas-flow\ncharacteristics by wing-type-vortex-generators inside a rectangular gas-flow\nduct of a plate-fin structure exhaust gas recirculation (EGR) cooler used in a\ncooled-EGR system. The analyses are conducted using computational fluid\ndynamics (CFD). The numerical modelling is designed as a gas-flow rectangular\nduct of an EGR cooler using two fluids with high temperature gas and\ncoolant water whose flow directions are opposite. The gas-flow duct used to\nseparate two fluids is assembled with a stainless steel material. The inlet temperature\nand velocity of gas flowed inside gas-flow duct are 400 deg C and 30\nm/s, respectively. Coolant water is flowed into two ducts on both a top and a\nbottom surface of the gas-flow duct, and the inlet temperature and velocity is\n80 deg C and 0.6 m/s, respectively. Wing-type-vortex-generators are designed to\nachieve good cooling performance and low pressure drop and positioned at\nthe center of the gas-flow duct with angle of inclination from 30 to 150 degrees\nat every 15 degrees. The temperature distributions and velocity vectors\ngained from numerical results were compared, and discussed. As a result, it is\nfound that the vortices guided in the proximity of heat transfer surfaces play\nan important role in the heat transfer enhancement and low pressure drop.\nThe collapse of the vortices is caused by complicated flow induced in the\ncorner constituted by two surfaces inside gas-flow duct.
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