The Development of Polymer-Based Flat Heat Pipes

Author

Oshman, Christopher ; Shi, Bo ; Li, Chen ; Yang, Ronggui ; Lee, Y.C. ; Peterson, G.P. ; Bright, Victor M.

Author_Institution

Dept. of Mech. Eng., Univ. of Colorado at Boulder, Boulder, CO, USA

Volume

20

Issue

2

fYear

2011

fDate

4/1/2011 12:00:00 AM

Firstpage

410

Lastpage

417

Abstract

In this paper, polymer-based flat heat pipes (PFHPs) with a thickness on the order of 1 mm have been successfully developed and tested. Liquid-crystal polymer (LCP) films with copper-filled thermal vias are employed as the case material. A copper micropillar/woven mesh hybrid wicking structure was designed and fabricated to promote evaporation/condensation heat transfer and the liquid supply to the evaporator of the PFHP. Water was selected as the working fluid because of its superior thermophysical properties. An experimental study was conducted to examine the PFHP performance. The test data demonstrated that the PFHP can operate with a heat flux of 11.94 W/cm² and results in effective thermal conductivity ranging from 650 to 830 W/m · K, with the value varying with the input heat flux and the tilt angle. With the employment of flexible LCP as casing material, the PFHP could potentially be directly integrated into a printed circuit board or flexible circuits for thermal management of heat-generating components.

Keywords

copper; heat pipes; heat transfer; liquid crystal polymers; materials testing; microfabrication; polymer films; thermal conductivity; thermal management (packaging); Cu; PFHP; condensation heat transfer; copper micropillar; copper-filled thermal vias; effective thermal conductivity; evaporation; flexible LCP; flexible circuits; heat flux; heat-generating components; liquid-crystal polymer films; polymer-based flat heat pipes; printed circuit board; size 1 mm; thermal management; thermophysical property; tilt angle; working fluid; woven mesh hybrid wicking structure; Conductivity; Copper; Heat transfer; Heating; Polymers; Cooling; flat heat pipe (FHP); hybrid wick; polymer;

fLanguage

English

Journal_Title

Microelectromechanical Systems, Journal of

Publisher

ieee

ISSN

1057-7157

Type

jour

DOI

10.1109/JMEMS.2011.2107885

Filename

5713207