CONJUGATE HEAT TRANSFER OF A DISK-SHAPED MINIATURE HEAT PIPE Ya-Wei Lee and Chih-Wei Chang Department of Mechanical Engineering, National Taiwan University, Taiwan Jr-Ming Miao Department of Mechanical Engineering, Chung Cheng Institute of Technology, National Defense University, Taiwan Ping-Hei Chen Department of Mechanical Engineering, National Taiwan University, Taiwan This study employs a computational fluid dynamics (CFD) software package to obtain a two-phase three-dimensional flow field and conjugate heat transfer results for a disk-shape miniature heat pipe (DMHP) that is used to dissipate heat from a laser diode. A mixture model is introduced into the governing equations for calculating the quality of mixture in the two-phase flow field. Predicted thermal resistances are presented at three different fluid charge volumes of 18%, 55%, and 92% at different heating powers of the laser diode. The predicted thermal resistance of the DMHP agrees well with measured results given in our previous study [1]. INTRODUCTION A laser diode has been popularly used as a light source in many applications for providing stable coherent light beam at specific wavelength. It is usually pack- aged in a very compact form for use in consumer electronic devices. However, it can generate large heat flux in such a compact volume when it emits light. Without proper dissipation of the heat generated, the temperature rise of the laser diode can affect not only the light duration of the diode but also the emitted wavelength. Vari- ous cooling devices such as heat spreaders and micro heat sinks have been proposed to control the laser diode temperature. Among many cooling devices, a miniature heat pipe (MHP) is one of the better choices for heat dissipation for its merits of low cost, compact size, passive operation, packaging flexibility, large thermal con- ductance, and high operational reliability. The application of MHPs in improving heat dissipation rate in electric devices is of great interest and is studied widely [2–5]. In practical operation, the cooling device should be of similar shapes as the Received 28 January 2005; accepted 22 June 2005. The authors deeply appreciate the National Science Council (NSC-94-2212-E-002-017) for provid- ing the funding for this work. The work in this study could not be achieved without their support. Address correspondence to Ping-Hei Chen, Mechanical Engineering Department, National Taiwan University, No. 1, Roosevelt Road Sec. 4, Taipei 10617, Taiwan. E-mail: phchen@ntu.edu.tw 25 Numerical Heat Transfer, Part A, 49: 25–45, 2006 Copyright # Taylor & Francis Inc. ISSN: 1040-7782 print=1521-0634 online DOI: 10.1080/10407780500301960