CN114217294A

CN114217294A - Laser wind finding radar heat transfer method and device based on closed servo cavity

Info

Publication number: CN114217294A
Application number: CN202111520147.XA
Authority: CN
Inventors: 赵世军; 张虞; 单雨龙; 倪荣萍; 田树银; 尹志军
Original assignee: National University of Defense Technology
Current assignee: National University of Defense Technology
Priority date: 2021-12-13
Filing date: 2021-12-13
Publication date: 2022-03-22

Abstract

The heat transfer method of the laser wind-measuring radar based on the closed servo cavity is characterized in that the heat generated when a laser light source and an amplifier, a linear power supply, a high-speed acquisition card and heating electronic elements in a detector circuit in a laser wind-measuring radar servo system work is designed by adopting a triple heat dissipation structure, and the heat dissipation function is realized by combining; the back wall of a servo system shell of the heating electronic element is provided with a radiator, the radiator is tightly attached to the back wall of the shell and has a surrounding fin structure, the contact area with air is increased, the radiating efficiency is increased, and the back wall of the shell is made of aluminum alloy; the soaking plate is closely attached to the rear wall (cover) of the shell, and each heating source in the shell is closely attached to the soaking plate in a connecting way, so that the internal heat can be transmitted out through the rear wall cover of the shell in time; the shell of the clothes system is an integrated aluminum alloy casting, all component supports in a casting cavity and a rear shell with a heat dissipation structure are integrally formed, and heating components are embedded in the components.

Description

Laser wind finding radar heat transfer method and device based on closed servo cavity

Technical Field

The invention relates to a heat transfer method design of a laser wind-measuring radar, which can effectively conduct the temperature of a small-closed-cavity high-power laser radar and enable components such as a seed light source, an amplifier and the like to have a temperature environment suitable for the components to work. The heat transfer method and the heat transfer device designed by the time can meet the heat dissipation requirements of a laser with the maximum power of 150W and the heat dissipation requirements of the size of about 200mm multiplied by 58mm and 240mm multiplied by 170mm multiplied by 40 mm. Making the lidar detection range longer, but smaller in size.

Background

The laser wind-finding radar is a detection system which uses laser as a detection medium, coherent detection as a frequency discrimination means, optical fibers as optical channels among devices, and aerosol particles or aerosol particles in the atmosphere as a detection target to remotely sense atmospheric wind field information. The laser wind measuring radar needs to perform one-dimensional or two-dimensional scanning to obtain the radial wind speed in the designated direction or invert the three-dimensional wind profile, and implement meteorological monitoring, aviation service and the like.

The lidar itself is designed for outdoor scenes, and may encounter the conditions of humid air, sand dust, salt mist and the like, so the design generally requires the design of a closed chamber.

The laser wind-finding radar can integrate a seed light source, an amplifier, a linear power supply, a high-speed acquisition card, a detector, a telescope and the like into a case, the case is kept fixed, the telescope points to the zenith direction vertically, a two-dimensional servo mechanism is designed above a lens, the sky is scanned through the rotation of the lens, and then a three-dimensional wind profile, a head-on wind profile of a lower runway of an airport and the like are inverted.

Two-dimensional servo mechanism has two kinds of solutions, firstly adopt 2 45 speculum to reflect the laser light path, servo slewing mechanism makes two speculums pivot respectively, and then realizes modes such as continuous scanning, full hemisphere scanning, user-defined scanning. Wherein, high-precision positioning control and surface type adjustment are key technologies. An alternating current servo motor provided with a precise encoder can be adopted, the high-precision positioning precision of the rotary table is guaranteed, and meanwhile, the angle information of the rotary table is obtained through feedback. In addition, on one hand, a precise machining process is adopted to reduce the transmission error of the transmission device, and on the other hand, the transmission error can be corrected through motor control, so that the final high-precision positioning and control of the rotary table are realized. In order to avoid water condensation on the inner reflector and the inner wall of the emergent window, a heating device is designed on the glass; in order to avoid the water condensation outside the exit window, a blowing device is designed. The two-dimensional servo mechanism has high design difficulty and high installation and adjustment requirements, and is not beneficial to being used in scenes such as high-speed maneuvering, shipborne and the like because the precision is reduced after the two-dimensional servo mechanism works for a period of time.

The second mode is to adopt a two-dimensional scanning servo system with mature technology sold in the market, integrate a seed light source, an amplifier, a linear power supply, a high-speed acquisition card, a detector, a telescope and the like in the scanning servo system and directly drive the telescope to scan the sky. The mode has low installation requirement, extremely high system integration level, good stability, excellent environmental adaptability of the servo system and small volume and strong maneuverability. However, this method needs to seal the scanning servo mechanism to meet the requirements of the use environment of the optical-electromechanical components. Meanwhile, a large amount of heat generated by the optical electromechanical device needs to be transmitted to the outer wall of the servo system in time, the temperature is reduced through heat exchange with the outside atmosphere, and the heat transmission design is one of key technologies. And a high-temperature-resistant resin layer or glass-sealed inert gas is adopted as an encapsulating layer in the radar. The inert gas isolates the influence of water vapor, floating dust, impurities and the like on the optical-mechanical-electrical device.

In a second two-dimensional scanning servo system, a heat dissipation method adopted by a laser radar which is currently used more commonly is as follows:

the radar of short distance low-power consumption has previously adopted and has set up components such as transmitting light source, photosensitive element on the PCB board, and PCB connects the heat dissipation part again and connects. The heat generated by the emitting light source and the photosensitive element is dissipated through the PCB and the heat dissipation component. The components are conducted to the heat dissipation part through the PCB, so that the heat dissipation efficiency is low, and the requirements of high power and small closed space cannot be met. When the temperature in the laser radar cavity is higher than 65 ℃, the laser seed source cannot start to work.

The heat dissipation requirement of the high-power small closed space does not exist before, and the traditional air cooling and water cooling can not meet the requirement: because the chamber is a closed space, conventional air cooling cannot be used. The fan can help the internal air flow to circulate, but the heat of the fan cannot be dissipated, so that the temperature in the closed cavity is higher. If water is used for conducting heat, if a water channel is broken, the safety of the radar is difficult to ensure, and damage which is difficult to recover can be caused.

Disclosure of Invention

The invention aims to provide a laser wind finding radar heat transfer method and device based on a closed servo cavity, and mainly relates to the design of the heat transfer method and device in the closed cavity of the laser wind finding radar, so that a seed light source, an amplifier, a linear power supply, a high-speed acquisition card, a detector and other components can still be in an appropriate working temperature range after the laser radar works for a long time, and the problem of heat transfer of a large amount of heat generated by an optical electromechanical device is solved.

The invention has the technical scheme that the heat transfer method of the laser wind-finding radar based on the closed servo cavity is characterized in that the heat generated when a laser light source and an amplifier in a servo system, a linear power supply, a high-speed acquisition card and a heating electronic element in a detector circuit work is designed by adopting a triple heat dissipation structure, and the heat dissipation function is realized by combining; the servo system shell rear wall of the heating electronic element is provided with the radiator, the radiator is tightly attached to the shell rear wall and is of a surrounding fin structure, the contact area between the radiator and air is increased, the radiating efficiency is improved, the shell rear wall is made of aluminum alloy, and the heat conductivity coefficient is 3-4 times larger than that of structural steel. The back lid wall design 3mm does benefit to heat-conduction to the external world. As shown in figure 1.

Secondly, the soaking plate is tightly attached to the back wall (cover) of the shell, and the connection is used for tightly attaching internal heating sources such as the seed light source, the amplifier, the heat dissipation end of the linear power supply and the like to the soaking plate and tightly attached to the back wall (cover) of the shell, so that the internal heat can be timely transmitted out through the back wall (cover) of the shell, as shown in the attached figure 2.

And thirdly, the aluminum alloy casting with the integrated servo system shell is formed by integrally molding all component supports and a rear shell with a heat dissipation structure in a casting cavity, and the heating components are embedded in the aluminum alloy casting. The heat collecting and exchanging system comprises a concentrated heat exchange plate 2, a heating component cover 1 and a heat conducting system (a heat pipe/a vapor chamber) 3.

The laser light source and the linear amplifier of the intracavity heating source are arranged in the heating component housing in the figure, the housing material of the heating component is red copper material with the thickness of 0.5mm-1mm, the heating component is completely embedded in the housing, the contact surface adopts silver-containing silicone grease with high heat conductivity coefficient or liquid metal to fill the gap, and the way of completely wrapping for 4 weeks is adopted, so that the whole heat of the heat source can be concentrated on the housing, and the heat is difficult to radiate to the air in the cavity. The outer surface of the heating component housing is welded with heat-conducting copper pipe heat pipes or aluminum soaking plates on the periphery (the upper surface, the lower surface, the left surface and the right surface), the contact surface can be well contacted by a welding mode, the heat dissipation efficiency is increased, in the complex motion, the good mechanical connection performance can be ensured by the welding mode, the heat conductivity of a heat conduction system is about 1000 times that of pure aluminum, the heat accumulated on the heating component housing in the steps can be quickly conducted away, the other end of the heat conduction system is connected with a sheet type concentrated heat exchange plate, the material is cast aluminum or aluminum-magnesium alloy with the thickness of 3-5mm, the cast aluminum or the aluminum-magnesium alloy has larger heat capacity in metal, and the material with the larger heat capacity can increase the passive heat dissipation redundancy. The concentrated heat exchange plate is fixed on the rear shell by threaded connection, and the contact surface is also made of silver-containing silicone grease or liquid metal with high thermal conductivity.

The triple heat dissipation structure comprises a heating component housing, a heat conduction system and a concentrated heat exchange plate, and firstly, how to transfer heat in the servo system as fast as possible is solved. A radiator is arranged on the rear wall of a shell of the servo system (a main heating electronic element or the rear wall of the shell is attached with a radiating fin), and the radiator is tightly attached to the rear wall of the shell and has a surrounding fin structure; the surrounding fin structure mainly exchanges heat by enlarging the heat exchange area.

The heat pipe and the heat pipe (vapor chamber) are arranged for heat dissipation, and are connected to tightly attach each internal heating source, such as a seed light source, an amplifier, a heat dissipation end of a linear power supply and the like, to the middle heat dissipation pipe and to the rear wall (cover) of the shell.

The integral aluminum alloy casting (shown in figures 1-2) is used for ensuring the high heat dissipation efficiency and the stable structure of the whole chamber by utilizing the high heat conductivity and the supporting strength of the aluminum alloy.

In order to ensure the stable operation of the laser radar, the heating module is integrated inside the laser radar, and meanwhile, the intelligent control and self-diagnosis functions are achieved by combining the temperature and humidity sensor, so that the internal temperature of the laser radar cavity can be effectively adjusted, and the stable operation of the laser radar is ensured.

The invention has the beneficial technical effects that: the invention uses the limited space to combine the heat generated when the light source in the servo system works with the amplifier, the linear power supply, the high-speed acquisition card and the heating electronic element in the detector circuit to realize the heat dissipation function by adopting the triple heat dissipation structure design. The combination of the middle radiating pipe and the heat pipe (vapor chamber) ensures that the heating source and the rear wall of the radiating shell form a temperature difference, and the heat flows from a high-temperature position to a low-temperature position through the radiating copper pipe to achieve balance of the internal temperature and the external temperature. The invention can effectively conduct the temperature in the closed cavity, timely reduces the overhigh temperature caused by the operation of the electric device in the closed cavity, ensures that the components in the closed cavity can be in a temperature environment suitable for the components to work, and has better application prospect in the field of heat conduction in the closed cavity.

Drawings

The radiator shown in the figure 1 is tightly attached to the rear wall of the shell, the surrounding fin structure is adopted, the fan fin structures are made in the small-consumption area as much as possible, the heat dissipation surface area is increased, the contact area between the heat dissipation surface area and air is effectively increased, the heat dissipation efficiency is improved, the manufacturing material of the rear wall of the shell is aluminum alloy, and the heat conductivity coefficient is 3-4 times larger than that of structural steel.

Fig. 2 is a schematic view showing the mounting of the vapor chamber of the present invention, the heat generating component casing of fig. 2 is provided with a vapor chamber,

fig. 3 and 4 are schematic diagrams of a servo system rear cover, and fig. 4 is a partial close-up exploded view of fig. 3.

Detailed Description

As shown in the figure, the heat transfer method of the laser wind-finding radar based on the closed servo cavity adopts a triple heat dissipation structure design for heat generated when a light source and an amplifier in a servo system, a linear power supply, a high-speed acquisition card and a heating electronic element in a detector circuit work, and the heat dissipation function is realized through combination.

The triple heat dissipation structure includes one problem to solve how to transfer heat inside the servo system as fast as possible. The servo system shell rear wall (main heating electronic component or the shell rear wall attached with the radiating fin) of the heating electronic component is provided with a radiator, the radiator is attached to the shell rear wall, the fan fin structure is made in a small-consumption area to increase the radiating surface area for surrounding the fin structure, the contact area with air is effectively increased, the radiating efficiency is increased, the shell rear wall is made of aluminum alloy, and the heat conductivity coefficient is 3-4 times larger than that of structural steel. The back lid wall design 3mm does benefit to heat-conduction to the external world. As shown in figure 1. The surface of the heat conducting copper pipe or the aluminum soaking plate is provided with a heat radiation fan.

The vapor chamber is a vacuum chamber (a block heat pipe) with a fine structure on the inner wall, and is usually made of copper. When heat is conducted to the evaporation zone from the heat source, the cooling liquid in the cavity starts to generate the gasification phenomenon of the cooling liquid after being heated in the environment with low vacuum degree, at the moment, heat energy is absorbed, the volume rapidly expands, the whole cavity is rapidly filled with gaseous cooling medium, and the condensation phenomenon can be generated when the gaseous working medium contacts a relatively cold zone. The heat accumulated during evaporation is released by the condensation phenomenon, and the condensed cooling liquid returns to the evaporation heat source through the capillary tube of the microstructure, and the operation is repeated in the cavity.

The heat dissipation of the heat-dissipating device is the same as the working principle: the operation principle of the vapor chamber is similar to that of a heat pipe, and the vapor chamber comprises four main steps of conduction, evaporation, convection and solidification. The vapor chamber is a two-phase fluid device formed by injecting pure water into a container filled with microstructures. The heat enters the plate from the external high-temperature area through heat conduction, and the water around the point heat source can quickly absorb the heat and gasify into steam to take away a large amount of heat energy. By utilizing the latent heat of the water vapor, when the steam in the plate is diffused from the high-pressure area to the low-pressure area (namely, the low-temperature area), the steam contacts the inner wall with lower temperature, the water vapor is rapidly condensed into liquid and releases heat energy. The convection and solidification are that the condensed water flows back to the heat source point by the capillary action of the microstructure to complete a heat transfer circulation and form a two-phase circulation system with the coexistence of water and water vapor.

The working principle of the soaking plate is as follows: the soaking plate does not need a power supply and any moving component, and is a completely closed passive device.

The principle of the soaking plate and the heat pipe is the same as the theoretical framework, and only the heat conduction mode is different, the heat conduction mode of the heat pipe is one-dimensional and is a linear heat conduction mode, and the heat conduction mode of the soaking plate is two-dimensional and is a surface heat conduction mode. The method is more suitable for the mode of needing rapid heat dissipation.

The heat dissipation plate needs an electronic product that dissipates high heat quickly.

Because the laser amplifier is the most main internal heat generating device of laser radar, when heat can not be spread out in time, can make sealed chamber temperature too high, when exceeding the highest working set point of components and parts, can lead to laser radar stop work. The soaking plate is connected to the laser amplifier in a clamping mode. In order to ensure the maximum effect, the four sides are connected in a clamping or screwing mode.

The laser radar has the advantages that the radiation is too good, the radiation is also possibly too good, the temperature in the cavity is lower than the minimum preset value of the temperature and humidity detector when the laser radar is in a low-temperature state, and the laser radar cannot be started, so that a heating device is arranged on the opposite side close to the seed source, and the seed source can be heated to a proper temperature to be quickly started when the seed source is relatively low and stable. A large amount of heat generated by the amplifier after a fast start can be soaked by the vapor chamber.

And thirdly, the aluminum alloy casting is integrated, and the high heat dissipation efficiency and the stable structure of the whole cavity are ensured by utilizing the high heat conductivity and the high supporting strength of the aluminum alloy. Utilize 3D to print rapid prototyping and 5 axle finishing impressions technique, with all components and parts supports of intracavity and the backshell integrated into one piece that has heat radiation structure, forming material is the aluminum alloy, and the components and parts that generate heat are embedded wherein, such mode can utilize all support frames of all intracavitys as heat conduction system, can be even concentrate on the backshell with the heat is whole, utilizes the great heat radiating area of backshell to carry out the heat exchange, has eliminated because of connecing the problem that contact failure leads to the radiating efficiency to reduce. Example (c): no. 7075 aluminum alloy is adopted as a material of an integral aluminum alloy casting, and 7075 aluminum alloy is cold-processed forging alloy which has high strength and is far better than mild steel. 7075 is one of the most powerful alloys in commerce. The 7075 aluminum alloy has compact structure and strong corrosion resistance effect, and is optimal for aviation and marine plates. Ordinary corrosion resistance, good mechanical property and anode reaction. The fine grains make the deep drilling performance better and the wear resistance of the tool is enhanced. The heat conductivity coefficient thereof was 173W/(m.multidot.K), and the specific heat thereof was 0.96J/(g.multidot.K). The heat conductivity is strong.

The connection mode between the radar heat dissipation devices is as follows: clamping or screwing; the whole heat dissipation device realizes high space utilization rate of the small sealed cavity and ensures stable work of the high-power small sealed cavity laser radar.

The other is that a middle radiating pipe and a heat pipe (and a soaking plate) are arranged for radiating, and are connected to tightly attach each internal heating source, such as a seed light source, an amplifier, a radiating end of a linear power supply and the like, to the middle radiating pipe and to the rear wall (cover) of the shell. Thirdly, an integrated aluminum alloy casting (shown in figures 3 and 4) is adopted, and high heat dissipation efficiency and a stable structure of the whole chamber are ensured by utilizing high heat conductivity and supporting strength of the aluminum alloy.

Claims

1. A laser wind-measuring radar heat transfer method based on a closed servo cavity is characterized in that the heat generated when a laser light source and an amplifier, a linear power supply, a high-speed acquisition card and a heating electronic element in a detector circuit in a laser wind-measuring radar servo system work is designed by adopting a triple heat dissipation structure, and the heat dissipation function is realized by combination; the back wall of a servo system shell of the heating electronic element is provided with a radiator, the radiator is tightly attached to the back wall of the shell and has a surrounding fin structure, the contact area with air is increased, the radiating efficiency is increased, and the back wall of the shell is made of aluminum alloy; the vapor chamber is closely attached to the rear wall cover of the shell, and each internal heating source is closely attached to the vapor chamber in a connected manner, so that internal heat can be transmitted out through the rear wall cover of the shell in time; the shell of the clothes system is an integrated aluminum alloy casting, all component supports in a casting cavity and a rear shell with a heat dissipation structure are integrally formed, and heating components are embedded in the components.

2. The heat transfer method of the laser wind-finding radar based on the closed servo cavity as claimed in claim 1, wherein the material of the housing of the heating device is red copper with the thickness of 0.5mm-1mm, the heating device is completely embedded in the housing, and the contact surface is filled with silver-containing silicone grease with high thermal conductivity or liquid metal.

3. The heat transfer method of the laser wind-finding radar based on the closed servo cavity as claimed in claim 2, wherein the heat source is totally concentrated on the housing by completely wrapping the periphery, and heat-conducting copper pipe heat pipes or aluminum vapor chambers are welded on the periphery of the outer surface of the housing of the heating component, namely the upper surface, the lower surface, the left surface and the right surface.

4. The laser wind-measuring radar heat transfer method based on the closed servo cavity as claimed in claim 2, wherein a heat dissipation fan is arranged on the surface of the heat conducting copper pipe or the aluminum soaking plate.

5. The heat transfer device of the laser wind-measuring radar based on the closed servo cavity in any one of the methods of claims 1 to 4 is characterized in that the heat generated when a laser light source and an amplifier in a servo system of the laser wind-measuring radar, a linear power supply, a high-speed acquisition card and a heating electronic element in a detector circuit work is designed by adopting a triple heat dissipation structure, and the heat dissipation function is realized by combination; the back wall of a servo system shell of the heating electronic element is provided with a radiator, the radiator is tightly attached to the back wall of the shell and has a surrounding fin structure, the contact area with air is increased, the radiating efficiency is increased, and the back wall of the shell is made of aluminum alloy; the vapor chamber is closely attached to the rear wall cover of the shell, and each internal heating source is closely attached to the vapor chamber in a connected manner, so that internal heat can be transmitted out through the rear wall cover of the shell in time; the shell of the clothes system is an integrated aluminum alloy casting, all component supports in a casting cavity and a rear shell with a heat dissipation structure are integrally formed, and heating components are embedded in the components; the heating device housing is made of red copper with the thickness of 0.5mm-1mm, the heating device is completely embedded in the housing, and the contact surface is filled with silver-containing silicone grease with high heat conductivity coefficient or liquid metal.