Patent Application
20140319239
The present disclosure relates generally to synthetic jet ejectors, and more particularly to thermal management systems which comprise a heat pipe, heat fins and a synthetic jet ejector.
A variety of thermal management devices are known to the art, including conventional fan based systems, piezoelectric systems, and synthetic jet ejectors. The latter type of system has emerged as a highly efficient and versatile thermal management solution, especially in applications where thermal management is required at the local level.
Various examples of synthetic jet ejectors are known to the art. Earlier examples are described in U.S. Pat. No. 5,758,823 (Glezer et al.), entitled “Synthetic Jet Actuator and Applications Thereof”; U.S. Pat. No. 5,894,990 (Glezer et al.), entitled “Synthetic Jet Actuator and Applications Thereof”; U.S. Pat. No. 5,988,522 (Glezer et al.), entitled Synthetic Jet Actuators for Modifying the Direction of Fluid Flows”; U.S. Pat. No. 6,056,204 (Glezer et al.), entitled “Synthetic Jet Actuators for Mixing Applications”; U.S. Pat. No. 6,123,145 (Glezer et al.), entitled Synthetic Jet Actuators for Cooling Heated Bodies and Environments”; and U.S. Pat. No. 6,588,497 (Glezer et al.), entitled “System and Method for Thermal Management by Synthetic Jet Ejector Channel Cooling Techniques”.
Further advances have been made in the art of synthetic jet ejectors, both with respect to synthetic jet ejector technology in general and with respect to the applications of this technology. Some examples of these advances are described in U.S. 20100263838 (Mahalingam et al.), entitled “Synthetic Jet Ejector for Augmentation of Pumped Liquid Loop Cooling and Enhancement of Pool and Flow Boiling”; U.S. 20100039012 (Grimm), entitled “Advanced Synjet Cooler Design For LED Light Modules”; U.S. 20100033071 (Heffington et al.), entitled “Thermal management of LED Illumination Devices”; U.S. 20090141065 (Darbin et al.), entitled “Method and Apparatus for Controlling Diaphragm Displacement in Synthetic Jet Actuators”; U.S. 20090109625 (Booth et al.), entitled Light Fixture with Multiple LEDs and Synthetic Jet Thermal Management System”; U.S. 20090084866 (Grimm et al.), entitled Vibration Balanced Synthetic Jet Ejector”; U.S. 20080295997 (Heffington et al.), entitled Synthetic Jet Ejector with Viewing Window and Temporal Aliasing”; U.S. 20080219007 (Heffington et al.), entitled “Thermal Management System for LED Array”; U.S. 20080151541 (Heffington et al.), entitled “Thermal Management System for LED Array”; U.S. 20080043061 (Glezer et al.), entitled “Methods for Reducing the Non-Linear Behavior of Actuators Used for Synthetic Jets”; U.S. 20080009187 (Grimm et al.), entitled “Moldable Housing design for Synthetic Jet Ejector”; U.S. 20080006393 (Grimm), entitled Vibration Isolation System for Synthetic Jet Devices”; U.S. 20070272393 (Reichenbach), entitled “Electronics Package for Synthetic Jet Ejectors”; U.S. 20070141453 (Mahalingam et al.), entitled “Thermal Management of Batteries using Synthetic Jets”; U.S. 20070096118 (Mahalingam et al.), entitled “Synthetic Jet Cooling System for LED Module”; U.S. 20070081027 (Beltran et al.), entitled “Acoustic Resonator for Synthetic Jet Generation for Thermal Management”; U.S. 20070023169 (Mahalingam et al.), entitled “Synthetic Jet Ejector for Augmentation of Pumped Liquid Loop Cooling and Enhancement of Pool and Flow Boiling”; U.S. 20070119573 (Mahalingam et al.), entitled “Synthetic Jet Ejector for the Thermal Management of PCI Cards”; U.S. 20070119575 (Glezer et al.), entitled “Synthetic Jet Heat Pipe Thermal Management System”; U.S. 20070127210 (Mahalingam et al.), entitled “Thermal Management System for Distributed Heat Sources”; U.S. 20070141453 (Mahalingam et al.), entitled “Thermal Management of Batteries using Synthetic Jets”; U.S. Pat. No. 7,252,140 (Glezer et al.), entitled “Apparatus and Method for Enhanced Heat Transfer”; U.S. Pat. No. 7,606,029 (Mahalingam et al.), entitled “Thermal Management System for Distributed Heat Sources”; U.S. Pat. No. 7,607,470 (Glezer et al.), entitled “Synthetic Jet Heat Pipe Thermal Management System”; U.S. Pat. No. 7,760,499 (Darbin et al.), entitled “Thermal Management System for Card Cages”; U.S. Pat. No. 7,768,779 (Heffington et al.), entitled “Synthetic Jet Ejector with Viewing Window and Temporal Aliasing”; U.S. Pat. No. 7,784,972 (Heffington et al.), entitled “Thermal Management System for LED Array”; and U.S. Pat. No. 7,819,556 (Heffington et al.), entitled “Thermal Management System for LED Array”.
In one aspect, a device is provided which comprises (a) a thermally conductive base having first and second major surfaces; (b) a die attached to said first major surface of said base; (c) a heat pipe having a first end which is attached to said second major surface of said base; (d) a plurality of heat fins attached to a second end of said heat pipe; and (e) at least one synthetic jet ejector disposed between said base and said plurality of heat fins.
The operation of a synthetic jet ejector and the formation of a synthetic jet may be appreciated with respect to
The movement of the flexible diaphragm 111 may be controlled by any suitable control system 117. For example, the diaphragm may be moved by a voice coil actuator. The diaphragm 111 may also be equipped with a metal layer, and a metal electrode may be disposed adjacent to, but spaced from, the metal layer so that the diaphragm 111 can be moved via an electrical bias imposed between the electrode and the metal layer. Moreover, the generation of the electrical bias can be controlled by any suitable device, for example but not limited to, a computer, logic processor, or signal generator. The control system 117 can cause the diaphragm 111 to move periodically or to modulate in time-harmonic motion, thus forcing fluid in and out of the orifice 113.
Alternatively, a piezoelectric actuator could be attached to the diaphragm 111. The control system would, in that case, cause the piezoelectric actuator to vibrate and thereby move the diaphragm 111 in time-harmonic motion. The method of causing the diaphragm 111 to modulate is not particularly limited to any particular means or structure.
The operation of the synthetic jet ejector 101 will now be described with reference to
c depicts the synthetic jet ejector 101 as the diaphragm 111 is controlled to move outward with respect to the chamber 105, as depicted by arrow 127. The chamber 105 has its volume increased and ambient fluid 115 rushes into the chamber 105 as depicted by the set of arrows 129. The diaphragm 111 is controlled by the control system 117 so that, when the diaphragm 111 moves away from the chamber 105, the vortices 123 are already removed from the edges of the orifice 113 and thus are not affected by the ambient fluid 115 being drawn into the chamber 105. Meanwhile, a jet of ambient fluid 115 is synthesized by the vortices 123, thus creating strong entrainment of ambient fluid drawn from large distances away from the orifice 109.
Many improvements have been made to the design of synthetic jet ejectors since their initial introduction. However, the need exists for even further improvements in the design of these devices. In particular, some applications require thermal management solutions which are highly compact, and which can accommodate certain geometrical constraints, such as cylindrical spaces. Some of these applications also additionally require the locus at which heat is dissipated into the atmosphere to be removed from the heat source. Some of these applications further require the ability for an end user or manufacturer to be able to adjust the thermal management capacity of a host device after the synthetic jet ejector (or its spatial footprint) has already been incorporated into the device. These design constraints cannot be met with many of the thermal management designs proposed to date.
It has now been found that the foregoing needs may be addressed with the devices and methodologies disclosed herein. These devices and methodologies may be utilized to provide thermal management solutions which are highly compact, which can accommodate certain geometrical constraints (such as cylindrical spaces), and which permit the locus at which heat is dissipated into the atmosphere to be removed from the heat source. Moreover, these devices may be produced as modular units, and/or as units which provide manufacturers or end users with the ability to increase the thermal capacity of the thermal management system through the addition of further synthetic jet ejectors or synthetic jet actuators to the existing structure or footprint of the thermal management system. These devices and methodologies are described in greater detail below.
The base 203 has first 211 and second 213 major surfaces and preferably comprises a thermally conductive material. Various materials may be used in the construction of the base including, for example, copper, aluminum, thermally conductive polymeric materials, and various metals and metal alloys.
In a typically implementation, a die (not shown) is attached to the first major surface 211 of the base 203, and a first end of the heat pipe 205 is attached to the second major surface 213 of the base 203. The attachment of the die or the first end of the heat pipe 205 may be accomplished mechanically, through the use of a suitable adhesive, or by other suitable means. If an adhesive is used for this purpose, the use of a thermally conductive adhesive is preferred.
A second end of the heat pipe 205 is in thermal communication with, and is preferably attached to, the heat sink 207. The attachment of the heat pipe 205 to the heat sink 207 may be accomplished mechanically, through the use of a suitable adhesive, or by other suitable means. If an adhesive is used for this purpose, the use of a thermally conductive adhesive is preferred. The heat sink 207 may have various configurations, but preferably comprises a plurality of heat fins 215 which are disposed radially about the center of the heat sink 207 and the heat pipe 205.
The base 203 is preferably spaced apart from the heat sink 207. At least one, and preferably a plurality, of synthetic jet ejectors 209 are disposed in the space between the base 203 and the heat sink 207. Each synthetic jet ejector 209 preferably emits a plurality of synthetic jets, and each synthetic jet is directed into the channel defined by adjacent heat fins 215 in the heat sink 207.
The manner in which the synthetic jet ejectors 209 may be attached to the heat sink 207 may be understood with reference to FIGS. 6 and 9-13. As best seen in
The above description of the present invention is illustrative, and is not intended to be limiting. It will thus be appreciated that various additions, substitutions and modifications may be made to the above described embodiments without departing from the scope of the present invention. Accordingly, the scope of the present invention should be construed in reference to the appended claims.
This application claims the benefit of priority to U.S. Provisional Application No. 61/768,189, filed Feb. 22, 2013, having the same title, and the same inventors, and which is incorporated by reference herein in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61768189 | Feb 2013 | US |
