Radially oscillating flow hybrid cooling system for low profile electronics applications

Abstract

The radially oscillating flow hybrid cooling system, in the following referred to as RADIOS, provides a thin form factor cold plate with radial spreading of heat to a larger area. A small liquid volume (<10 ml) is hermetically sealed within the system and does not require external hose connections. Four membrane pumps running in a phase-delayed manner induce a constant-speed, oscillating direction fluid flow at the chip source that continuously shuttles heat to an extended periphery and returns cool liquid to the chip. In the peripheral branches, heat is transferred from the liquid to solid structures and finally dissipated to the air. A micro-scale copper mesh enables low-resistance heat transfer (solid-liquid and liquid-solid) in a thin form factor (< 2 mm). Narrow channels between the discrete heat exchanger areas optimize the spreading performance and reduce the fluid volume. Numerical modeling shows an effective conductivity of 20X and 50X over bulk copper for the spreader plates and the interconnecting tubes, respectively. The technology presented here promotes modular liquid cooling units for low-profile computing systems without incurring the risk of flooding associated with conventional liquid cooling circuits. © 2008 IEEE.