Laser Thermal Management Systems And Methods

• US 20080198883A1
• Filed: 02/20/2007
• Published: 08/21/2008
• Est. Priority Date: 02/20/2007
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Vetrovec, Jan
• Granted Patent: US 7,532,652 B2
• Time in Patent Office: Days
• US Class Current: 372/35
• CPC Class Codes: F25B 9/02 using Joule-Thompson effect; using vortex effect
• CPC Class Codes: F25D 19/006 Thermal coupling structure or interface
• CPC Class Codes: F41H 13/005 the high-energy beam being a laser beam
• CPC Class Codes: H01S 3/0404 Air- or gas cooling, e.g. by dry nitrogen
• CPC Class Codes: H01S 3/0407 Liquid cooling, e.g. by water
• CPC Class Codes: H01S 3/042 for solid state lasers H01S3/0401 takes precedence
• CPC Class Codes: H01S 3/2308 Amplifier arrangements, e.g. MOPA

Abstract

A laser system thermal management system includes a laser gain assembly and a thermal management assembly. The laser gain assembly includes a laser gain medium and may include laser pump diodes. The thermal management system includes a high pressure gas tank connected to an open-cycle Joule-Thompson refrigerator. Cooled and partially liquefied gas is introduced into a reservoir. The reservoir may be in good direct thermal contact with the laser gain assembly or via a closed loop recirculating fluid heat exchanger. The heat generated by the laser gain assembly is removed by heat exchange with the cooled gas and condensate in the reservoir either by direct thermal contact or via the recirculating heat exchanger loop. Gas evaporating in the reservoir is vented.

Claims

1. A laser thermal management system comprising:

a thermal management assembly comprising;

an open cycle Joule-Thompson refrigerator adapted for receiving high pressure gas and cooling the gas;

a reservoir fluidly connected to the Joule-Thompson refrigerator, the reservoir adapted to receive at least partially condensed gas from the Joule-Thompson refrigerator;

a laser gain assembly in good thermal contact with the thermal management assembly; and

wherein the reservoir is adapted to vent gases evaporating as a result of heat exchanged between the laser gain assembly and the thermal management assembly.

2. The system of claim 1, further comprising a high pressure gas tank fluidly connected to the Joule-Thompson refrigerator.

3. The system of claim 1, wherein the laser gain assembly further comprises a laser gain medium.

4. The system of claim 3, wherein the laser gain assembly further comprises one or more laser pump diodes.

5. The system of claim 1, wherein the laser gain medium is in good thermal contact with the thermal management assembly.

6. The system of claim 1, wherein the one or more pump diodes are in good thermal contact with the thermal management assembly.

7. The system of claim 1, further comprising the laser gain medium in good thermal contact with the reservoir.

8. The system of claim 1, further comprising the one or more pump diodes in good thermal contact with the reservoir.

9. The system of claim 1, wherein the thermal assembly further comprises:

a first heat exchanger in good thermal contact with the reservoir;

a second heat exchanger; and

a pump fluidly connected to the first heat exchanger and the second heat exchanger, wherein the pump, first and second heat exchanger are connected in a closed fluid circulating loop.

10. The system of claim 9, wherein the laser gain medium is in good thermal contact with the second heat exchanger.

11. The system of claim 9, wherein the one or more pump diodes are in good thermal contact with the second heat exchanger.

12. The system of claim 2, wherein the high pressure gas tank contains gas at a pressure of at least 1,000 psi.

13. The system of claim 2, wherein the high-pressure gas tank contains gas selected from a group consisting of nitrogen, argon, ethane, penthane, and Halon™

.

14. The system of claim 2, wherein said high-pressure gas tank contains a gas mixture consisting essentially of nitrogen, ethane, and pentane.

15. The system of claim 3, wherein the laser gain medium contains lasant ions selected from the group consisting of Nd3+, Yb3+, Ho3+, Tm3++, Er3+, and Ti3+.

16. The system of claim 3, wherein the laser gain medium may be formed in the shape selected from the group consisting of a rod, a disk, and a slab.

17. A method of removing heat from a laser system, the method comprising:

receiving high pressure gas, cooling and partially condensing the gas;

receiving at least partially condensed gas into a reservoir of a thermal management system;

venting gases from the reservoir evaporating as a result of heat exchanged between a laser gain assembly and the thermal management assembly; and

wherein the laser gain assembly is in good thermal contact with the thermal management assembly.

18. The method of claim 17, further comprising:

feeding a high-pressure gas through a filter and a dryer to remove moisture and particulates before cooling and partially condensing the gas.

19. The method of claim 17, further comprising:

exchanging heat generated by the laser gain assembly with the reservoir of the thermal management assembly, wherein the laser gain assembly is in good thermal contact with the reservoir.

20. The method of claim 17, further comprising:

cooling a fluid in a first heat exchanger in good thermal contact with the reservoir of the thermal management assembly;

pumping the cooled fluid to a second heat exchanger with a pump via a closed loop;

cooling the laser gain assembly in good contact with the second heat exchanger; and

returning the fluid warmed by thermal contact with the laser gain assembly to the first heat exchanger via the close loop pump.

21. A laser thermal management system comprising:

means for providing high pressure gas;

means for cooling and partially condensing the gas;

means for receiving the cooled and partially condensed gas;

means for providing good thermal contact between the cooled gas receiving means and a laser gain assembly; and

means for vent gases evaporating as a result of heat exchanged between the laser gain assembly and the cooled gas receiving means.