Bubble generator

• US 20050279491A1
• Filed: 09/14/2004
• Published: 12/22/2005
• Est. Priority Date: 06/18/2004
• Status: Active Grant

• Current Assignee: Ecole polytechnique fãdãrale de lausanne epfl (Schweizerische Eidgenossenschaft)
• Original Assignee: Ecole polytechnique fãdãrale de lausanne epfl (Schweizerische Eidgenossenschaft)
• Inventors: Thome, John R., Dupont, Vincent
• Granted Patent: US 7,261,144 B2
• Time in Patent Office: Days
• US Class Current: 165/272
• CPC Class Codes: F28D 15/0266 with separate evaporating and condensing chambers connected by at least one conduit; Loop-type heat pipes; with multiple or common evaporating or condensing chambers F28D15/043 takes precedence
• CPC Class Codes: F28D 15/06 Control arrangements therefor
• CPC Class Codes: F28F 2250/08 Fluid driving means, e.g. pumps, fans
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A heat transfer assembly for transferring heat from a heat generating device to a circulating fluid, said heat transfer assembly comprising an evaporator device having at least one microchannel formed therein, in thermally conductive contact with said heat generating device, a condenser device, actuating means and manifold means for circulating said fluid between said evaporator device and said condenser device, wherein said heat transfer assembly further comprises a bubble generator capable to create bubbles in said at least one microchannel at a controlled frequency.

Claims

1. A bubble generator for generating bubbles within a tubular liquid flow, comprising

means for generating one bubble at a pre-determined location within said tubular liquid flow,

means for repeating periodically said bubble generating step at said location, and

means for controlling the frequency of said periodical bubble generating step,

wherein said tubular liquid flow is carried out within a microchannel, and wherein said bubbles consist of vapor of said liquid.

2. A bubble generator as claimed in claim 1, wherein said frequency is a pre-determined fixed frequency of between 5 Hz and 500 Hz.

3. A bubble generator as claimed in claim 1, wherein said frequency is a pre-determined fixed frequency, of between 20 Hz and 60 Hz.

4. A bubble generator as claimed in claim 1, wherein said frequency is adjustable between 5 Hz and 500 Hz.

5. A bubble as claimed in claim 4, wherein said frequency is adjustable upon a temperature measurement.

6. A bubble generator as claimed in claim 1, wherein it comprises wire means for connecting said bubble generating means to a control circuit providing periodically varying electric energy and transducer means connected to said wire means, capable to transfer said electric energy to said liquid in a form selected from thermal and mechanical energy.

7. A bubble generator as claimed in claim 6, wherein said transducer means comprise an electrically resistive part.

8. A bubble generator as claimed in claim 6, wherein said transducer means comprise a capacitor.

9. A bubble generator as claimed in claim 6, wherein said transducer is an electrohydrodynamic transducer.

10. A bubble generator as claimed in claim 6, wherein said transducer is selected from sonic and ultrasonic transducers.

11. A bubble generator as claimed in claim 6, wherein said transducer is a piezo electric transducer.

12. A bubble generator as claimed in claim 1, comprising a laser impacting said location, and a shutter cutting off the beam of said laser at said frequency.

13. A bubble generator as claimed in claim 1, comprising a reservoir containing said vapor of said liquid and port means alternatively cutting off and communicating with said microchannel at said frequency.

14. A bubble generator as claimed in claim 1, wherein said location is located in the flow path within said microchannel.

15. A bubble generator as claimed in claim 1, wherein said location is a nucleation chamber in fluid communication with the flow in said microchannel.

16. A bubble generator as claimed in claim 15, wherein said nucleation chamber is located in the wall of said microchannel.

17. A heat transfer assembly for transferring heat from a heat generating device to a circulating fluid, said heat transfer assembly comprising

an evaporator device having at least one microchannel formed therein, in thermally conductive contact with said heat generating device,

a condenser device,

actuating means and manifold means for circulating said fluid between said evaporator device and said condenser device,

wherein said heat transfer assembly further comprises a bubble generator as claimed in claim 1.

18. A heat transfer assembly as claimed in claim 17, comprising at least one temperature sensor sensing a temperature of a wall of said evaporator device, wherein the frequency of said bubble generator is adjustable in function of said sensed temperature.

19. A process for cooling a heat generating electronic device by means of a cooling liquid, implementing a heat transfer assembly as claimed in claim 17.

20. A process as claimed in claim 19, wherein said cooling liquid is set in a saturated condition at the inlet of said bubble generator.

21. A process as claimed in claim 19, wherein the frequency of bubble generation is continuously adjusted in function of a temperature measurement.