Title: Technical note: Optimisation of the defroster ducts and windshield electric resistances of a city bus with CFD analysis

Authors: Salih Ozen Unverdi, Hayri Eren, Vadi Erdem, Nilgun Sonmez, Alper Emre, Volkan Bayraktar

Addresses: TEMSA Global Research, Development and Technology Company, TUBITAK MAM Technology Free Zone, 41470 Gebze, Kocaeli, Turkey. ' TEMSA Global Research, Development and Technology Company, TUBITAK MAM Technology Free Zone, 41470 Gebze, Kocaeli, Turkey. ' TEMSA Global Research, Development and Technology Company, TUBITAK MAM Technology Free Zone, 41470 Gebze, Kocaeli, Turkey. ' TEMSA Global Research, Development and Technology Company, TUBITAK MAM Technology Free Zone, 41470 Gebze, Kocaeli, Turkey. ' TEMSA Global Research, Development and Technology Company, TUBITAK MAM Technology Free Zone, 41470 Gebze, Kocaeli, Turkey. ' TEMSA Global Research, Development and Technology Company, TUBITAK MAM Technology Free Zone, 41470 Gebze, Kocaeli, Turkey

Abstract: The windshield and side windows defrosting system performance of a city bus is improved with CFD analysis. The air flow rate is increased by reducing the pressure drop in the air inlet and outlet ducts. The air flow is evenly distributed among the vents by optimising the shape of the outlet duct. The heat transfer rate to the windshield is increased by adjusting the width of the vents and defrosting time is decreased by orienting the vents. The air speeds measured near the windshield increased by 350%. Defrosting 95% of the Area A on the windshield within 40 minutes, at Q-80 thermal conditions, is accomplished. But de-icing 80% of the Area B, in front of the driver, within 20 minutes cannot be fulfilled, because the defrost-box heat power is insufficient. To speed up de-icing, electric resistance wires are used as additional heat source. Air flow inside a defrost-box is analysed.

Keywords: CFD; computational fluid dynamics; HVAC; defroster ducts; electrical resistance; de-icing; air ducts; shape optimisation; jet; phase change; windshield; vehicle design; windshields; city buses; window defrosting; air flow rate; heat transfer; air speeds.

DOI: 10.1504/IJVD.2010.029644

International Journal of Vehicle Design, 2010 Vol.52 No.1/2/3/4, pp.199 - 221

Published online: 30 Nov 2009 *

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