A Numerical Study on Natural Convection Heat Transfer of Handheld Projectors with a Fin Array

Jin-Cherng Shyu,Tsuni Chang,Shun-Ching Lee

doi:10.3390/en10030266

Abstract

This study numerically investigates the effects of the number of bottom openings and the fin spacing on both the natural convection heat transfer and airflow field of the handheld projector with various orientations. The horizontally-oriented 120 mm × 53 mm × 19 mm handheld projector, which had 11 bottom openings and was installed with either 7 plate fins or 13 rows of square pin, was considered as the primary case. The fin number varied from 6 plates to 13 plates or from 7 pin rows to 16 pin rows, while the bottom openings varied from 11 to 15 in this study with handheld projector held at a specified inclination ranging from −90° to 90°. The results showed that the heat transfer coefficient of a specific surface of the plate-fin array installed in the primary handheld projector increased from 6 to 7 W/m2·K as the heating power increased from 2 W to 7 W. The optimal fin spacing in the handheld projector possessing 11 bottom openings was 2.875 mm and 3.375 mm for the plate-fin and pin-fin, respectively, at a heating power of 7 W. Although the velocity magnitude of the airflow between fins increased as the bottom opening increased, it was not able to offset the reduction of the airflow velocity resulting from the fin spacing reduction.

Highlights

Cooling hot electronic chips in an enclosure under natural convection condition is sometimes favorable because of numerous advantages that active cooling technique using blowers cannot achieve, such as noiseless, energy-saving and cost reduction
This study numerically investigates the effects of the number of bottom openings and the fin spacing on the natural convection heat transfer and airflow field of the handheld projector with spacing on the natural convection heat transfer and airflow field of the handheld projector with various various orientations
The fin number varied from 6 plates to 13 plates or from 7 rows of pin to 16 rows of pin, while the number of the bottom openings varied from 11 to 15 in this study with handheld projector held at a specified inclination ranged from −90◦ to 90◦

Summary

Introduction

Cooling hot electronic chips in an enclosure under natural convection condition is sometimes favorable because of numerous advantages that active cooling technique using blowers cannot achieve, such as noiseless, energy-saving and cost reduction. Numerous heat transfer correlations on the natural convection of an isolated surface with various inclinations in form of Nu = CRan have been proposed [3,4,5,6,7,8] To some degree, those heat transfer studies on an isolated surface formed the foundation of numerous following studies which investigated various effects on the natural convection heat transfer of a fin array in an infinite, still medium [9,10,11,12,13,14,15,16,17,18]. Because the airflow of free convection is induced by buoyancy, the orientation of the fin array plays an important role in heat transfer

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