Spatially distributed ventilation boundary using electrohydrodynamic fluid accelerators

Abstract

In thermal management systems that employ EHD devices to motivate flow of air through an enclosure, spatial distribution of a ventilation boundary may facilitate reductions in flow resistance by reducing average transit distance for cooling air from an inlet portion of the ventilation boundary to an outlet portion. Some thermal management systems described herein distribute a ventilation boundary over opposing surfaces, adjacent surfaces or even a single surface of an enclosure while providing a short, “U” shaped, “L” shaped or generally straight through flow path. In some cases, spatial distributions of the ventilation boundary facilitate or enable enclosure geometries for which conventional fan or blower ventilation would be impractical. In some cases, provision of multiple portions of the ventilation boundary may allow the thermal management system to tolerate blockage or occlusion of a subset of the inlet and / or outlet portions and, when at least some of such portions are non-contiguous spatially-distributed, tolerance to a single cause of blockage or occlusion is enhanced.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S)[0001]The present application claims the benefit of U.S. Provisional Application No. 61 / 113,225, filed Nov. 10, 2008. The present application is also related to commonly-owned, co-pending U.S. patent application Ser. No. ______, entitled “ELECTROHYDRODYNAMIC FLUID ACCELERATOR WITH HEAT TRANSFER SURFACES OPERABLE AS COLLECTOR ELECTRODE,” naming Jewell-Larsen, Honer, Schwiebert, Ran, Savalia and Zhang as inventors, and to commonly-owned, co-pending U.S. patent application Ser. No. ______, entitled “REVERSIBLE FLOW ELECTROHYDRODYNAMIC FLUID ACCELERATOR,” naming Jewell-Larsen, Honer, Schwiebert, Ran, Savalia and Zhang as inventors, each filed on even date herewith.BACKGROUND[0002]1. Field[0003]The present application relates to thermal management, and more particularly, to micro-scale cooling devices that use electrohydrodynamic (EHD, also known as electro-fluid-dynamic, EFD) technology to generate ions and electrical fields to control the moveme...

AI Technical Summary

Benefits of technology

[0009]EHD devices may be employed to motivate flow of air in a thermal management system, such as employed to exhaust heat dissipated by integrated circuits in computing devices and electronics. For example, in devices such as laptop computers, compact scale, flexible form factor and absence of moving parts can provide design and user advantages over conventional forced air cooling technologies that rely exclusively on fans or blowers. EHD device solutions can operate silently (or at least comparatively so) with reduced volume and mass. In some cases, products incorporating EHD device solutions may be thinner and lighter than those employing conventional forced air cooling technologies. Flexible form factors of EHD devices can facilitate compelling product designs and, in some cases, may provide functional benefits.

[0010]It has been discovered that in thermal management systems that employ EHD devices to motivate flow of air through an enclosure, spatial distribution of a ventilation boundary may facilitate reductions in flow resistance by reducing average transit distance for cooling air from an inlet portion of the ventilation boundary to an outlet portion. In some cases, spatial distributions of the ventilation boundary facilitate or enable enclosure geometries for which conventional fan or blower ventilation would be impractical. In some cases, the provision of multiple portions of the ventilation boundary may allow the thermal management system to tolerate blockage or occlusion of a subset of the inlet and / or outlet portions and, when at least some of such portions are non-contiguous spatially-distributed, tolerance to a single cause of blockage or occlusion is enhanced.

[0011]In some embodiments in accordance with the present invention, an apparatus includes an enclosure, plural flow paths for conveyance of air between ventilated boundary portions of the enclosure, and a first electrohydrodynamic fluid accelerator disposed in at least a respective one of the flow paths for ventilating the enclosure and thereby cooling one or more devices disposed therein. The ventilated boundary portions of the enclosure include a first outlet portion and at least two inlet portions. The at least two inlet portions are non-contiguous and spatially-distributed on the enclosure. The first electrohydrodynamic fluid accelerator is operable to motivate flow between respective portions of the ventilated boundary.

[0019]In some embodiments in accordance with the present invention, an apparatus includes an enclosure, plural flow paths, and plural electrohydrodynamic fluid accelerator instances. The plural flow paths are configured for conveyance of air between ventilated boundary portions of the enclosure, including plural outlet portions and plural inlet portions, wherein respective ones of the inlet and outlet portions are interspersed and spatially-distributed over a single boundary surface. The electrohydrodynamic fluid accelerator instances are each disposed in at least a respective one of the flow paths for ventilating the enclosure and thereby cooling one or more devices disposed therein, and are each operable to motivate flow between respective portions of the ventilated boundary.

Problems solved by technology

In some cases, spatial distributions of the ventilation boundary facilitate or enable enclosure geometries for which conventional fan or blower ventilation would be impractical.

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