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RECENT ADVANCES IN TWO-PHASE THERMAL GROUND PLANES

DOI: 10.1615/AnnualRevHeatTransfer.2015011163
pages 101-153

Scott M. Thompson
Department of Mechanical Engineering, Mississippi State University, Mississippi State, MS 39762

Hongbin Ma
Department of Mechanical and Aerospace Engineering, University of Missouri, Columbia, Missouri, 65211, USA


KEY WORDS: Heat Pipes, Heat Spreader, Vapor Chamber, Thermal Ground Plane, Flat-Plate Heat Pipe, Oscillating or Pulsating Heat Pipes, Thermal Spreading, High Heat Flux

Abstract

The continual miniaturization and sophistication of power electronics has resulted in higher heat fluxes−driving thermal management away from single-phase, metallic heat spreaders/sinks toward two-phase heat spreaders or thermal ground planes (TGPs). TGPs are capable of achieving ultra-high effective thermal conductivities and mitigating concentrated heat fluxes upward of 1 kW/cm2. Their advancement, however, will require further research and development, especially with regard to novel wicking structures, surface preparations, flow path configurations, and ultrathin form factors. In so doing, the TGP will continue to be an effective surface-to-sink (noninvasive) thermal management device capable of meeting stringent application constraints such as size, weight, and power. This chapter focuses on the recent advances in TGPs−specifically vapor chambers and flat-plate oscillating heat pipes−for achieving the next generation of high heat flux transport. An emphasis on novel wicking structures, surface engineering, overall geometry/shapes, and thermal performance will be provided. The ongoing challenges for achieving the next-generation TGP for highly efficient thermal spreading will be discussed in detail.

ARHT Digital Library

Illustration of composite TIMs with a percolation of spherical nanoparticles, and high aspect ratio nanowires. NANOSTRUCTURED THERMAL INTERFACES
Photograph of copper/diamond sintered wick structure. RECENT ADVANCES IN TWO-PHASE THERMAL GROUND PLANES
The microchannel with a single pillar used by Jung et al., and an SEM image of the pillar with a flow control slit at 180 deg (facing downstream). ADVANCED CHIP-LEVEL LIQUID HEAT EXCHANGERS
Schematics of thermal boundary conductance calculations. NONEQUILIRIUM MOLECULAR DYNAMICS METHODS FOR LATTICE HEAT CONDUCTION CALCULATIONS