CN106654818A - High-power solid laser thermal management system - Google Patents

Abstract

The invention discloses a high-power solid-state laser thermal management system. The system includes: a first cooling chamber, a first liquid-filled chamber, a second liquid-filled chamber and a second cooling chamber connected in sequence; wherein, the first refrigeration unit, the first cooling chamber, the first liquid-filled chamber and the second refrigeration unit The unit, the second cooling cavity, and the second liquid-filled cavity are symmetrical structures with the laser gain medium as the central axis. The liquid-filled cavity on either side of the symmetrical structure is filled with liquid metal, and the heat of the laser gain medium is transferred to the liquid metal through heat conduction. ;The cooling chamber is filled with refrigerant, and the refrigerant undergoes a phase change in the cooling chamber to absorb the heat transferred to the cooling chamber through the liquid metal; the refrigeration unit cools the phase-changed refrigerant to below the boiling point and enters again in the cooling chamber. The invention eliminates the problem of thermal expansion coefficient mismatch between the solder and the gain medium in the traditional welding process, and can dissipate the heat of the laser gain medium to the external environment to the greatest extent.

Description

A high power solid-state laser thermal management system

technical field

The invention relates to the field of electronic devices, in particular to a high-power solid-state laser thermal management system.

Background technique

In a high-power solid-state laser system, most of the pump light absorbed by the laser gain medium is converted into waste heat and deposited inside the gain medium, resulting in an increase in the temperature of the gain medium. Due to the external cooling and the characteristics of the Gaussian distribution of the pump light, there is a large temperature gradient inside the gain medium, and the corresponding thermal stress and strain, as well as the change in the refractive index of the gain medium, will eventually lead to a decrease in laser output power and a decrease in beam quality. . In the development of lasers, thermal effects have always been a major obstacle restricting the development of lasers in the direction of ultra-high power and high-quality beam quality.

Worldwide, the cooling method widely used in solid-state lasers is to weld the gain medium and the heat sink together by welding, and then provide deionized water with a lower temperature through refrigeration equipment to take away the heat generated by the laser by forced convection. The problem that has always been insurmountable in this method is that a specific solder is required for soldering, and the thermal expansion coefficient of the solder cannot exactly match the gain medium, and the contact thermal resistance of the soldering is far beyond the acceptable range, so new thermal interface materials and thermal Packaging technology and more efficient heat dissipation methods to meet the needs of laser cooling.

Contents of the invention

In order to meet the cooling requirements of the laser, the invention provides a high-power solid-state laser thermal management system.

A high-power solid-state laser thermal management system provided by the present invention includes: a first cooling cavity, a first liquid-filled cavity, a second liquid-filled cavity, and a second cooling cavity connected in sequence;

The first cooling chamber shares chamber wall A with the first liquid-filled chamber, the first liquid-filled chamber shares chamber wall B with the second liquid-filled chamber, and the second liquid-filled chamber shares chamber wall B with the first liquid-filled chamber. The two cooling chambers share the chamber wall C, wherein the first refrigeration unit, the first cooling chamber, the first liquid-filled chamber and the second refrigeration unit, the second cooling chamber, and the second liquid-filled chamber are based on the chamber wall B is a symmetrical structure with a central axis, and the cavity wall B is a laser gain medium;

The liquid-filled cavity on either side of the symmetrical structure is filled with liquid metal, and the heat of the laser gain medium is transferred to the liquid metal through heat conduction; the heat absorbed by the liquid metal passes through the liquid-filled cavity and the The contact surface of the cooling chamber is transferred to the cooling chamber; the cooling chamber is filled with refrigerant, and the refrigerant undergoes a phase change in the cooling chamber to absorb and transfer to the cooling chamber through the liquid metal internal heat; the refrigeration unit cools the phase-changed refrigerant to below the boiling point and enters the cooling cavity again, so that the refrigerant is in a stable flow state and can be recycled.

The beneficial effects of the present invention are as follows:

In the embodiment of the present invention, liquid metal is used as the thermal interface between the laser gain medium and the heat sink, which increases the thermal conductivity of the thermal interface, and at the same time eliminates the problem of the thermal expansion coefficient mismatch between the solder and the gain medium in the traditional welding process, and can maximize the Dissipate the heat of the laser gain medium to the external environment, effectively reduce the temperature of the laser gain medium, reduce the thermal stress deformation caused by the uneven temperature of the laser gain medium, and improve the quality of the laser beam and output power.

Description of drawings

Fig. 1 is a cross-sectional view of a high-power solid-state laser thermal management system according to an embodiment of the present invention;

Fig. 2 is the top view of the laser gain medium in the embodiment of the present invention;

Among them, 1. The first refrigeration unit; 2. The first cooling chamber; 3. The first liquid-filled chamber; 4. The second liquid-filled chamber; 5. The second cooling chamber; 6. The second refrigeration unit; 7. Metal porous Medium; 8. Wire spring; 9. Laser gain medium.

detailed description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided for more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

In order to meet the cooling requirements of lasers, the present invention provides a thermal management system for high-power solid-state lasers. The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

According to an embodiment of the present invention, a high-power solid-state laser thermal management system is provided. FIG. 1 is a cross-sectional view of a high-power solid-state laser thermal management system according to an embodiment of the present invention. As shown in FIG. 1 , the high-power solid-state laser thermal management system according to an embodiment of the present invention The power solid-state laser thermal management system includes: the first refrigeration unit 1, the first cooling chamber 2, the first liquid-filled chamber 3, the second liquid-filled chamber 4, the second cooling chamber 5 and the second refrigeration unit 6 connected in sequence, as follows Each module of the embodiment of the present invention is described in detail.

Specifically, the first cooling cavity 2 shares cavity wall A with the first liquid-filled cavity 3, the first liquid-filled cavity 3 shares cavity wall B with the second liquid-filled cavity 4, and the second The liquid-filled cavity 5 shares the cavity wall C with the second cooling cavity 5, wherein the first refrigeration unit 1, the first cooling cavity 2, the first liquid-filled cavity 3 and the second refrigeration unit 6, the second The cooling cavity 5 and the second liquid-filled cavity 4 are symmetrical structures with the cavity wall B as the central axis, and the cavity wall B is a laser gain medium;

The liquid-filled cavity on either side of the symmetrical structure is filled with liquid metal, and the heat on one side of the laser gain medium is transferred to the liquid metal through heat conduction; the heat absorbed by the liquid metal passes through the liquid-filled cavity and the The contact surface of the cooling chamber is transferred to the cooling chamber; the cooling chamber is filled with refrigerant, and the refrigerant undergoes a phase change in the cooling chamber to absorb and transfer to the cooling chamber through the liquid metal. The heat in the chamber; the refrigeration unit cools the phase-changed refrigerant to below the boiling point and enters the cooling chamber again, so that the refrigerant is in a stable flow state and can be recycled.

The laser gain medium is located between two identical cooling structures to ensure uniform heat dissipation on both sides of the laser gain medium. Liquid metal fills the liquid-filled cavity to act as a thermal interface between the laser gain medium and the copper heat sink. In the present invention, the structure composed of the first cooling chamber 2, the first liquid-filled chamber 3, the second liquid-filled chamber 4, and the second cooling chamber 5 is called a heat sink. Specifically, the heat sink can be copper Heat sink.

That is, the first liquid-filled cavity 3 is filled with liquid metal, and the heat on one side of the laser gain medium is transferred to the liquid metal through heat conduction; the liquid metal transfers the absorbed heat to the The first cooling chamber 2; the first cooling chamber 2 is filled with refrigerant, and the refrigerant undergoes a phase change in the first cooling chamber 2 to absorb and transmit to the first cooling chamber through the liquid metal. The heat in the cooling chamber 2; the first refrigeration unit 1 cools the phase-changed refrigerant below the boiling point and enters the first cooling chamber 2 again, so that the refrigerant is in a stable flow state and can be circulated use;

The second liquid-filled chamber 4 is filled with the liquid metal, and the heat on the other side of the laser gain medium is transferred to the liquid metal through heat conduction; the liquid metal transfers the absorbed heat to the liquid metal through the chamber wall C. The second cooling chamber 5; the second cooling chamber 5 is filled with the refrigerant, and the refrigerant undergoes a phase change in the second cooling chamber 5 to absorb and transmit to the liquid metal through the liquid metal. The heat in the second cooling chamber 5; the second refrigeration unit 6 cools the phase-changed refrigerant below the boiling point and enters the second cooling chamber 5 again, so that the refrigerant is in a stable flow status and can be recycled.

The liquid metal is a special material that is in a liquid state at normal temperature and has high thermal conductivity and good electrical conductivity. Specifically, in the present invention, the melting point of the liquid metal (such as gallium, gallium-indium alloy, etc.) is 20-30° C., and will not chemically react with the liquid-filled cavity.

Specifically, vacuum holes and liquid metal filling holes are provided on the walls of the liquid-filled chambers (including the first liquid-filled chamber and the second liquid-filled chamber) on either side of the symmetrical structure; The cavity is evacuated into a low vacuum, and then the liquid metal is filled into the liquid-filled cavity through the liquid metal filling hole.

Specifically, the liquid-filled cavity on either side of the symmetrical structure further includes a metal porous medium suspended in the liquid-filled cavity and not in contact with the wall of the liquid-filled cavity.

More specifically, the porous metal medium is connected to the cavity wall of the liquid-filled chamber through several wire springs, that is, one end of the wire spring is welded on the porous metal medium, and the other end is welded on the porous metal medium. on the wall of the liquid-filled chamber, so that the metal porous medium is suspended in the liquid-filled chamber without contacting the side wall and bottom surface of the liquid-filled chamber.

More specifically, the metal porous medium can be a whole piece of porous material, or multiple pieces of small-volume porous material, which are connected to each other by metal wires to form a whole.

Specifically, the porous metal medium may be a porous medium with high thermal conductivity and large porosity, such as metal foam, metal fiber, and metal braid.

More specifically, the diameter of the wire spring is nanoscale or micronscale (less than 10 microns).

Specifically, the design evaporation temperature of the refrigerant (for example, R152a, R134a, etc.) in the refrigeration unit is 15-20°C.

Specifically, the geometric configuration of the laser gain medium is strip-shaped or disk-shaped.

Fig. 2 is a top view of the laser gain medium in an embodiment of the present invention. As shown in Fig. 2, the laser gain medium includes a crystal portion doped with rare earth elements and undoped rare earth elements located around the crystal portion doped with rare earth elements The crystal part of the laser gain medium, the contact surface of the first liquid-filled cavity and the second flushing cavity is the crystal part of the undoped rare earth element. The rare earth elements include Nd, Er, Yb and the like.

Wherein, in the crystal portion doped with rare earth elements, the doping concentration of rare earth elements is uniform in the crystal width and thickness directions, and increases first and then decreases in the crystal length direction, and the central plane in the length direction is The plane of symmetry is distributed symmetrically.

In the embodiment of the present invention, the liquid-filled cavity on either side of the liquid metal symmetrical structure is in a static state when it is not heated. Preferably, the liquid metal filled in the liquid-filled chamber on any side of the symmetrical structure contains nano-magnetic particles wrapped by surfactant; the cooling chamber on any side of the symmetrical structure also includes a cooling chamber connected to the liquid-filled chamber A communication pipeline and an electromagnetic pump; the electromagnetic pump drives the liquid metal containing nano-magnetic particles to circulate in the liquid-filled cavity and the cooling cavity through the communication pipeline.

That is, the first cooling chamber 2 also includes a first communication pipeline connected to the first liquid-filled chamber 3 and a first electromagnetic pump, and the first electromagnetic pump drives the liquid metal containing nano-magnetic particles in the Flow in the first communication pipeline; the second cooling chamber 5 also includes a second communication pipeline connected with the second liquid-filled chamber 4 and a second electromagnetic pump, and the second electromagnetic pump drives the The liquid metal of nano magnetic particles flows in the second communication pipeline.

Specifically, the cavity wall of the cooling cavity on either side of the symmetrical structure is porous, pin-fin-shaped, cylindrical, or corrugated microstructure; or the cavity wall of the cooling cavity on either side of the symmetrical structure is attached with carbon nanotube cilia array. That is, the walls of the first cooling cavity 2 and the second cooling cavity 5 are porous, pin-finned, cylindrical, or corrugated microstructures; or the first cooling cavity 2 and the second cooling cavity The cavity wall of the cavity 5 is attached with a carbon nanotube cilia array.

Specifically, the cooling cavity on any side of the symmetrical structure is provided with inlets and outlets for refrigerant fluid to flow in and out.

The refrigerating unit on either side of the symmetrical structure may be a mechanical compression refrigerating unit, or an absorption refrigerating unit, or any other device that can ensure the circulation of the refrigerating medium and undergo phase change in the cooling cavity to absorb heat. refrigeration unit.

The working principle of a thermal management system for a high-power solid-state laser provided by an embodiment of the present invention is as follows: When the solid-state laser is working, the heat in the gain medium is transferred to the liquid metal in contact with it through heat conduction, and the liquid metal is unevenly heated Weak flow will occur, which will cause the wire spring to vibrate, and then drive the metal porous medium to vibrate, thereby accelerating the heat conduction inside the liquid metal. When the heat is transferred from the liquid metal to the cooling cavity, the refrigerant in the cooling cavity will undergo evaporation or boiling phase transition to achieve efficient heat transfer. The refrigeration unit will cool the phase-changed refrigerant to below the boiling point and send it back into the cooling chamber to provide continuous and efficient cooling.

Preferably, surfactant-wrapped nano-magnetic particles (such as Fe/Co/Ni and its alloy particles, Fe-N compound particles, etc.) can be added to the liquid metal, the inlet and outlet are set on the wall of the liquid-filled chamber, and the connected The pipeline and the electromagnetic pump drive the liquid metal to flow. On the one hand, it can increase the heat transfer between the liquid metal and the surface of the gain medium, so that the heat of the gain medium can be transferred to the liquid metal as soon as possible. On the other hand, the connecting pipeline can be set inside the cooling chamber , part of the heat absorbed by the liquid metal can be directly transferred to the refrigerant, increasing the heat transfer path from the liquid metal to the refrigerant, thereby accelerating the heat transfer rate.

A thermal management system for a high-power solid-state laser provided by an embodiment of the present invention has the following advantages: 1. Liquid metal is used as the thermal interface between the gain medium and the copper heat sink, which increases the thermal conductivity of the thermal interface and eliminates the need for traditional welding The thermal expansion coefficient mismatch between the solder and the gain medium in the process; 2. The metal porous medium with high thermal conductivity in the closed cavity of the copper heat sink can accelerate the heat conduction inside the liquid metal, and promote the heat in the gain medium to be transferred to the cooling cavity through the liquid metal as soon as possible 3. When the liquid metal in the closed cavity of the copper heat sink flows weakly due to uneven temperature, it will cause the wire springs that hang the metal porous medium to vibrate slightly, and then drive the vibration of the metal porous medium. Speed up the mixing of liquid metals at different temperatures in the closed chamber; 4. The refrigerant in the cooling chamber of the copper heat sink absorbs heat and evaporates or boils directly, with high heat transfer efficiency; 5. The refrigeration unit can ensure that the refrigerant is always in a flowing state , and the temperature is lower than its boiling point when entering the cooling chamber, ensuring the stable and safe start-up of the entire heat dissipation system without start-up failure; 6. The refrigerant in the heat management system can be recycled and will not cause environmental harm.

The above description is only an embodiment of the present invention, and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of the claims of the present invention.

Claims (10)

1. a kind of high power solid state laser heat management system, it is characterised in that include：The first refrigeration unit for being sequentially connected, First cooling chamber, the first topping up chamber, the second topping up chamber, the second cooling chamber and the second refrigeration unit；

First cooling chamber shares cavity wall A with the first topping up chamber, and the first topping up chamber is common with the second topping up chamber Use cavity wall B, the second topping up chamber and second cooling chamber share cavity wall C, wherein, it is first refrigeration unit, first cold But chamber, the first topping up chamber and second refrigeration unit, the second cooling chamber, the second topping up chamber are the right of the axle centered on cavity wall B Claim structure, cavity wall B is gain medium；

Liquid metal is filled with the topping up chamber of any side of the symmetrical structure, the heat of the gain medium is by warm Pass to the liquid metal；The liquid metal connecing by the topping up chamber and the cooling chamber by the heat of absorption Contacting surface passes to the cooling chamber；Refrigeration working medium is filled with the cooling chamber, the refrigeration working medium is sent out in the cooling chamber Give birth to phase transformation to absorb the heat conducted by the liquid metal to the cooling chamber；The refrigeration unit will undergo phase transition Refrigeration working medium is cooled to below boiling point and is again introduced into cooling chamber so that the refrigeration working medium in steady flow condition and Can be recycled.

2. high power solid state laser heat management system as claimed in claim 1, it is characterised in that

Also include being suspended in the topping up chamber in the topping up chamber of any side of the symmetrical structure, not with the cavity wall phase in topping up chamber The metal porous medium of contact.

3. high power solid state laser heat management system as claimed in claim 2, it is characterised in that the metal porous medium It is connected with the cavity wall in the topping up chamber by some one metal wire springs.

4. high power solid state laser heat management system as claimed in claim 3, it is characterised in that the wire spring A diameter of nanoscale or micron order.

5. high power solid state laser heat management system as claimed in claim 1, it is characterised in that the liquid metal it is molten Point is 20～30 DEG C, and chemical reaction will not occur with the topping up chamber；The design evaporation of refrigeration working medium in the refrigeration unit Temperature is 15～20 DEG C.

6. high power solid state laser heat management system as claimed in claim 1, it is characterised in that the gain medium Geometric configuration be lath-shaped or video disc shape.

7. high power solid state laser heat management system as claimed in claim 1, it is characterised in that the gain medium Crystal block section and the undoped p rare earth element positioned at the rare earth doped element crystal block section surrounding including rare earth doped element Crystal block section, the contact surface in the gain medium and the topping up chamber of any side of the symmetrical structure is the undoped p The crystal block section of rare earth element.

8. high power solid state laser heat management system as claimed in claim 7, it is characterised in that the rare earth doped element Crystal block section in, the doping content of the rare earth element uniformity on crystal width and thickness direction, in crystal length direction Upper first increase reduces again, and is symmetric as the plane of symmetry with the median plane on length direction.

9. high power solid state laser heat management system as claimed in claim 1, it is characterised in that the symmetrical structure is any Nano magnetic particle containing surfactant parcel in the liquid metal of the topping up chamber filling of side；

Also include connecting pipeline and the electromagnetic pump being connected with the topping up chamber in the cooling chamber of any side of the symmetrical structure；Institute State electromagnetic pump and order about the liquid metal containing nano magnetic particle by the connecting pipeline in the topping up chamber and cooling Circulate in chamber.

10. high power solid state laser heat management system as claimed in claim 1, it is characterised in that

The cavity wall of any side cooling chamber of the symmetrical structure is cellular, pin ribbed, cylindric or corrugated micro-structural；Or The cavity wall attachment CNT cilium array of any side cooling chamber of symmetrical structure described in person.