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ISSN Online: 2377-424X

International Heat Transfer Conference 12
August, 18-23, 2002, Grenoble, France

Thermal performance of SEMOS heat pipes

Get access (open in a dialog) DOI: 10.1615/IHTC12.2750
6 pages

Abstract

The present paper aims at the development of a high-performance heat spreader (HPHS) for air cooling of LSI chips. A candidate of HPHSs is a thin plate containing micro heat pipes. The so-called wicked heat pipe is a typical heat pipe, but its maximum heat-transport rate decreases rapidly for decreasing its diameter. In the present paper, we focused on the SEMOS heat pipes (self-exciting-mode oscillating-flow heat pipes) as a candidate of micro heat pipes. In the SEMOS heat pipes, the cold and the hot sections are connected with each other by a closed loop meandering between them and the loop is filled to a certain volume fraction with a working liquid. The SEMOS heat pipe has such a simple construction and so it is suitable for a micro heat pipe. The SEMOS heat pipes tested in the present experiments were twin-turn types which consisted of four straight tubes connected with each other by U-shaped tubes, and the experimental parameters tested were the inner diameter of the tube (D=0.8 and 2.4mm), the total temperature difference of heating and cooling water (ΔT=10 to 60K), and the liquid volume fraction (α=20 to 90%). Results obtained for the SEMOS heat pipes are summarized as follows: A twin-turn micro heat pipe of 0.8mm in diameter transports as large as 15W. The apparent thermal conductivity is not sensitive to the wall material and the initial vacuum level. The contribution of latent heat to the total heat transport is as small as 15% and it is conceivable that phase change is important to induce circulating or pulsating flows but the heat transport rate closely relates to sensible heat transport.