A numerical model for transport in flat heat pipes considering wick microstructure effects

Ram Ranjan, Purdue University - Main Campus
Jayathi Y. Murthy, Network for Computational Nanotechnology, School of Mechanical Engineering, Purdue University
Suresh V. Garimella, Purdue University
Unnikrishnan Vadakkan, Intel Corporation

Date of this Version



International Journal of Heat and Mass Transfer Volume 54, Issues 1–3, 15 January 2011, Pages 153–168


A transient, three-dimensional model for thermal transport in heat pipes and vapor chambers is developed. The Navier-Stokes equations along with the energy equation are solved numerically for the liquid and vapor flows. A porous medium formulation is used for the wick region. Evaporation and condensation at the liquid-vapor interface are modeled using kinetic theory. The influence of the wick microstructure on evaporation and condensation mass fluxes at the liquid-vapor interface is accounted for by integrating a microstructure-level evaporation model (micromodel) with the device-level model (macromodel). Meniscus curvature at every location along the wick is calculated as a result of this coupling. The model accounts for the change in interfacial area in the wick pore, thin-film evaporation, and Marangoni convection effects during phase change at the liquid-vapor interface. The coupled model is used to predict the performance of a heat pipe with a screen-mesh wick, and the implications of the coupling employed are discussed. (C) 2010 Elsevier Ltd. All rights reserved.


Nanoscience and Nanotechnology