A methodology for enhanced heat transport and storage that uses a new two-component fluid mixture consisting of a microencapsulated phase change material (microPCM) for enhanced latent heat transport is outlined. SBIR investigations for NASA, USAF, SDIO, and NSF since 1983 have demonstrated the ability of the two-component microPCM coolants to provide enhancements in heat transport up to 40 times over that of the carrier fluid alone, enhancements of 50 to 100 percent in the heat transfer coefficient, practically isothermal operation when the coolant flow is circulated in an optimal manner, and significant reductions in pump work.

Enhanced heat transport in environmental systems using microencapsulated phase change materials

The purpose of this paper is to present a review of the recent heat pipe research and development efforts in the Americas. After discussing the research and development of high performance monogroove, tapered artery, trapezoidally grooved, dual-slot, double wall artery, ceramic and other specially designed heat pipes, the transient modeling and testing efforts are reviewed for a variety of heat pipes that also includes variable conductance heat pipes and thermosyphons. The application of heat pipes to terrestrial systems is discussed for the heat recovery systems, Rankine and solar systems, fusion reactor core cooling and the thermal control of electronic equipment. The application of heat pipes to space systems includes the thermal control of space station and satellites, and the radiator design of large space power systems. Although many advances have been made in the past few years in the development of high heat transfer performance heat pipes, the heat pipe modeling efforts are not in step with the technological requirements.

Heat pipe research and development in the Americas

Two-phase flow and dryout in a screen wick saturated with a fluid mixture

According to one embodiment, a thermal management system is provided that includes at least one chassis frame configured to minimize a thermal spreading resistance of the thermal management system. The chassis frame included at least one chassis body, at least one thermal skeleton embedded into the chassis body, and a working fluid contained within the thermal skeleton and used to dissipate heat from the chassis body.

Thermal management systems and methods for heat generating electronics

The application of heat pipes for the thermal management of conduction-cooled avionic packages using VHSIC technology (l-W to 3-W chips) is addressed. Test results are used to show the increase in the allowable power of the conduction-cooled avionic package obtained with heat pipes. Thermal performance was satisfactory for both horizontal and vertical attitudes. Performance predictions with a finite-element model are used to provide an understanding of the constraints that limit thermal performance and package power. Two Hughes prototype heat pipes using methanol as the working fluid are evaluated for two package configurations: one for a pluggable 64-mm multichip module (MCM) dissipating 50 W and the other for single-chip modules (SCMs) surface-mounted on a printed wiring board (PWB). Both heat pipe designs are characterized relative to transport capacity, liquid blockage, and heat flux.

G. W. Scott

Papers

Evaluation of Heat Pipes for Conduction-Cooled Level II Avionic Packages