Library Subscription: Guest

ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Cooling of Electronic Components by Steady/Unsteady Air Flow

Get access (open in a dialog) DOI: 10.1615/IHTC15.min.008853
pages 4853-4867

Abstract

The presented study focuses on the heat transfer and power consumption characteristics of an electronic component cooling system and the detailed analysis of the airflow through its heat sink. A PC microprocessor is cooled by a typical air-cooling system, with the goal being to optimize the cooling system operation method and save energy. The cooling system is an off-the-shelf system, consisting of a parallel plate fin heat sink and adjoined axial fan. Thermal/power characteristics are experimentally obtained at steady and unsteady fan operation conditions. Different fan operation conditions are compared based on the performance parameter, COP. The cooling system is studied experimentally and analytically. Moreover, the particle image velocimetry (PIV) optical flow measurement technique is applied to analyze the flow inside a transparent experimental model of a heat sink channel. The flow in the different heat sink channels, as measured with PIV, strongly differs from channel to channel. This is mainly due to the position of the channel relative to the fan , which is unique for each channel. A certain part of the asymmetry between the channels relates to a partial obstruction of channel inlet by the fan hub for some channels. In addition, the lengthwise symmetry is broken between different sides of a given heat sink channel, due to fan induced swirl. These observations allow gaining some regarding the discrepancies of the thermal characteristics of the cooling systems in various heat sink flow-thermal numerical models, which rather assume uniform symmetrical and parallel airflow at the inlet to a channel and symmetrical distribution of heat transfer properties across the channels. The thermal and flow characteristics obtained in this study are being utilized to design a closed-loop control system, that adjusts fan speed and incorporates a combination of forced and natural convection phases in order to improve the cooling system performance (COP) for a variety of practically relevant (steady and unsteady) heat input conditions.