Cooling Electric Equipment
20 Feb 2015-pp 1-47
About: The article was published on 2015-02-20. It has received 2 citations till now. The article focuses on the topics: Thermoelectric cooling & Electronic component.
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TL;DR: In this paper, the authors proposed a novel step or trapezoid surface design applicable to air-cooled heat sink under cross flow condition, which can provide a higher heat transfer conductance and a lower pressure drop at a specified frontal velocity.
Abstract: The present study proposed a novel step or trapezoid surface design applicable to air-cooled heat sink under cross flow condition. A total of five heat sinks were made and tested, and the corresponding fin patterns are (a) plate fin; (b) step fin (step 1/3, 3 steps); (c) 2-step fin (step 1/2, 2 steps); (d) trapezoid fin (trap 1/3, cutting 1/3 length from the rear end) and (e) trapezoid fin (trap 1/2, cutting 1/2 length from the rear end). The design is based on the heat transfer augmentation via (1) longer perimeter of entrance region and (2) larger effective temperature difference at the rear part of the heat sink. From the test results, it is found that either step or trapezoid design can provide a higher heat transfer conductance and a lower pressure drop at a specified frontal velocity. The effective conductance of trap 1/3 design exceeds that of plate surface by approximately 38 % at a frontal velocity of 5 m s−1 while retains a lower pressure drop of 20 % with its surface area being reduced by 20.6 %. For comparisons exploiting the overall thermal resistance versus pumping power, the resultant thermal resistance of the proposed trapezoid design 1/3, still reveals a 10 % lower thermal resistance than the plate fin surface at a specified pumping power.
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TL;DR: The development of free convection in a viscous fluid between heated vertical plates is investigated in this paper, where the basic governing continuity, momentums and energy equations are expressed in finite difference form and solved numerically on a digital computer.
Abstract: The development of free convection in a viscous fluid between heated vertical plates is investigated. The basic governing continuity, momentums and energy equations are expressed in finite difference form and solved numerically on a digital computer. Results are obtained for the variations of velocity, temperature, and pressure throughout the flow field assuming the fluid to enter the channel with ambient temperature and a flat velocity profile. The flow and heat-transfer characteristics of the channel are studied and a development height established. A comparison is made between the results of this theoretical investigation and the experimental work of Elenbaas.
320 citations
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242 citations
TL;DR: In this article, the authors characterized local heat transfer coefficients for round, single-phase free liquid jets impinging normally against a flat uniform heat flux surface, and found that the local Nusselt number characteristics were dependent on nozzle diameter.
Abstract: The purpose of this investigation was to characterize local heat transfer coefficients for round, single-phase free liquid jets impinging normally against a flat uniform heat flux surface. The problems parameters investigated were jet Reynolds number Re, nozzle-to-plate spacing z, and jet diameter d. A region of near-constant Nusselt number was observed for the region bounded by 0 {le} r/d {le} 0.75, where is the radical distance from the impingement point. The local Nusselt number profiles exhibited a sharp drop for r/d > 0.75, followed by an inflection and a shower decrease thereafter. Increasing the nozzle-to-plate spacing generally decreased the heat transfer slightly. The local Nusselt number characteristics were found to be dependent on nozzle diameter. This was explained by the influence of the free-stream velocity gradient on local heat transfer, as predicted in the classical analysis of infinite jet stagnation flow and heat transfer. Correlations for local and average Nusselt numbers reveal an approximate Nusselt number dependence on Re{sup 1,3}.
219 citations
TL;DR: In this article, a multi-faceted experimental investigation has been carried out to study heat transfer and pressure drop for airflow in arrays of heat generating rectangular modules deployed along one wall of a flat rectangular duct.
213 citations