Title: A computational and experimental investigation of the metallisation effects on the thermal characteristics of an automotive exterior lighting lamp

Authors: Sercan Boduroglu; A. Alper Ozalp

Addresses: FARBA Automotive Lighting and Plastic Factory, Organize Sanayi Bolgesi, Sari Cad. No. 21 Nilufer, Bursa, Turkey ' Department of Mechanical Engineering, Uludag University, 16059 Gorukle, Bursa, Turkey

Abstract: This study was performed to describe the reflector metallisation effects considering the heat transfer characteristics and hot spot formation on an automotive exterior lamp. To form an accurate comparison, three reflectors were studied with emissivities of ε1 = 0.04, ε2 = 0.42 and ε3 = 0.95, which indicated the aluminium-coated, uncoated white and uncoated black reflectors, respectively. The discussion section is organised to address the numerical evaluations using computational fluid dynamics (CFD) and the experimental evaluations. The computational results indicated that, despite the variations in hconv and hrad with ε, the total heat transfer coefficients on the bulb's surface result in a constant value. Additionally, it is observed that the hot spot location on the lens moves to the centre area for a lower reflector emissivity (ε3→ ε1) as the radiation approaching the lens becomes more effective on the lens's temperature distribution. The numerical and experimental results are compared, and a good agreement is found between them.

Keywords: automotive lights; exterior lighting lamps; emissivity; reflector metallisation; convection; radiation; CFD; computational fluid dynamics; thermal characteristics; automobile industry; heat transfer; hot spot formation; bulb surfaces.

DOI: 10.1504/IJVD.2016.078784

International Journal of Vehicle Design, 2016 Vol.71 No.1/2/3/4, pp.279 - 299

Received: 08 Nov 2014
Accepted: 28 Nov 2015

Published online: 02 Sep 2016 *

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