CN116858001B - Evaporator and waste heat recovery system thereof - Google Patents

Abstract

The invention provides an evaporator, which comprises a cover plate and a bottom plate, wherein the bottom plate comprises a guide plate, a liquid storage tank, a gas-liquid outlet, a side slope, a micro-channel, a liquid inlet and a slope V-shaped groove, the liquid storage tank is arranged in the middle of the bottom plate, the micro-channel is arranged at two sides of the liquid storage tank, the guide plate is arranged at the upper part of the micro-channel, one side of the liquid storage tank is connected with an inlet of the evaporator, the outlet is arranged at the other side opposite to the inlet, the outlet is connected with an outflow channel, the outflow channel comprises a first part which is arranged at the outer side of the upper part of the micro-channel and is communicated with the micro-channel, a second part is arranged at one end of the outlet of the bottom plate and extends along one end of the outlet, the ends of the two sides of the second part are communicated with the first part, and the middle of the second part is communicated with the outlet. The invention designs the novel structure evaporator, the manifold arrangement structure and the micro-channel design in the evaporator prolong the working medium flowing time and the heat exchange area, improve the heat transfer efficiency, optimize the fluid flowing path and reduce the flowing resistance by adding the manifold plate structure and the liquid storage groove, reduce the pump power consumption, ensure the uniform distribution of the working medium and realize the efficient heat dissipation.

Description

Evaporator and waste heat recovery system thereof

Technical Field

The invention relates to a heat pipe technology, in particular to a loop heat pipe for waste heat recovery, and belongs to the field of F28d15/02 heat pipes.

Background

The heat pipe technology is a heat transfer element called a heat pipe invented by George Grover Luo Fo (Los Alamos) national laboratory in the United states of Amersham (1963), which fully utilizes the heat conduction principle and the rapid heat transfer property of a phase change medium, and rapidly transfers the heat of a heating object to the outside of a heat source through the heat pipe, and the heat conduction capacity of the heat pipe exceeds the heat conduction capacity of any known metal.

The heat pipe technology is widely applied to the industries of aerospace, military industry and the like before, since the heat pipe technology is introduced into the radiator manufacturing industry, the design thought of the traditional radiator is changed, a single radiating mode of obtaining a better radiating effect by simply relying on a high-air-volume motor is eliminated, the heat pipe technology is adopted to enable the radiator to obtain a satisfactory heat exchanging effect, and a new world of the radiating industry is opened up. At present, the heat pipe is widely applied to various heat exchange equipment, including the nuclear power field and the computer field, such as the waste heat utilization of nuclear power, and the like.

The loop heat pipe refers to a loop closed loop heat pipe. Typically consisting of an evaporator, a condenser, a liquid reservoir, and vapor and liquid lines. The working principle is as follows: the heat load is applied to the evaporator, the fluid evaporates on the outer surface of the evaporator capillary core, the generated vapor flows out of the vapor channel into the vapor pipeline, then enters the condenser to be condensed into liquid and supercooled, the reflux liquid enters the liquid trunk through the liquid pipeline to supply the evaporator capillary core for circulation, and the circulation of the fluid is driven by the capillary pressure generated by the evaporator capillary core without external power. Because the condensing section and the evaporating section are separated, the loop heat pipe is widely applied to comprehensive application of energy and recovery of waste heat.

With the increasing demand of server heat dissipation, the most common air cooling heat dissipation scheme of domestic data centers is difficult to reach the standard, and the cost of the liquid cooling heat dissipation scheme is extremely high. Aiming at the defects, the invention improves the existing loop heat pipe, and provides a novel waste heat recovery type pump driven two-phase loop heat pipe, which is based on a mechanical pump driven two-phase fluid loop technology and a waste heat recovery technology, meets the high heat flux heat dissipation requirement of a server, can recycle waste heat, and has the advantages of high heat dissipation capacity, low PUE value, high flexibility, capability of waste heat recovery and the like.

The heat absorption capacity of the evaporator is also an important factor in the heat absorption process, and the invention develops a novel structure evaporator aiming at the problem of low heat absorption efficiency of the existing evaporator.

Disclosure of Invention

The invention provides a waste heat recovery type pump driven two-phase loop heat pipe, which solves the technical problem of low heat exchange capacity of a heat dissipation loop heat pipe.

In order to achieve the above object, the technical scheme of the present invention is as follows:

The utility model provides an evaporator, the evaporator includes apron and bottom plate, and the bottom plate includes guide plate, reservoir, gas-liquid outlet, side slope, microchannel, inlet and slope V type groove, and the reservoir setting is in the bottom plate middle part, and the reservoir both sides set up the microchannel, at microchannel upper portion guide plate, reservoir one side and evaporator entry linkage, set up the export at the opposite side of entry, exit linkage outflow passageway, the outflow passageway is including setting up in the outside on microchannel upper portion and the first part that communicates with the microchannel, and the second part sets up in the export one end of bottom plate and extends along export one end tip, and the tip and the first part intercommunication of second part both sides, the middle part and the export intercommunication of second part.

Preferably, the microchannel is disposed in communication with the first portion at a location at an end of the first portion remote from the second portion.

Preferably, the baffle is disposed adjacent to the first portion, and a portion of the microchannels, which are not covered by the baffle, are reserved between the first portion and the baffle, the portion of the microchannels forming an exhaust passage for the vapor to escape.

Preferably, the second portion is not in communication with the microchannel and the reservoir.

Preferably, the first portion is disposed between the inlet and the outlet at a position near the outlet, the length being 1/3-1/4 of the distance between the inlet and the outlet.

Preferably, the first portion is an inclined structure, and gradually gets deeper from the outside to the inside; the second part is a slope V-shaped groove; gradually deepening from two ends to the center, and the lowest point is arranged at the outlet position.

Preferably, the bottom wall of the first portion is inclined downwardly in the direction of the second portion to ensure that liquid can enter the second portion.

Preferably, the V-groove configuration is 145-155.

Preferably, the liquid ammonia flows into the evaporator liquid storage tank through a pipeline, the liquid level is gathered in the liquid storage tank to rise, after the liquid level rises to a certain height, the liquid ammonia diffuses to two sides and flows into the micro-channel, the bottom of the micro-channel 2-5 is a heat source, at the moment, the fluid starts to absorb heat, when the temperature of the fluid reaches the boiling point, vaporization is started, the fluid is converted into a gaseous state from the liquid state, the gaseous fluid is heated to rise, a gas transmission path is changed under the action of a guide plate, the guide plate plays the role of changing a gas phase working medium flow path, the liquid working medium is heated to evaporate and then becomes a gaseous state, and the gas phase working medium is heated to rise, but due to the blocking action of the guide plate, the gaseous wages can not be discharged from the top layer in the evaporator and can only be discharged from a micro-channel below the guide plate; when the liquid fluid continuously absorbs heat and the vaporization process is continuously carried out, more and more gas is accumulated in the evaporator cavity, the gas moves downwards under the action of the guide plate 2-1, passes through the guide plate and upwards to enter the exhaust channel, then steam enters the outflow channel and finally is discharged from the outlet.

The utility model provides a waste heat recovery loop heat pipe system, includes pre-heater, evaporimeter, condenser, reservoir, pump and regenerator, and pre-heater, evaporimeter, regenerator, condenser, reservoir pass through the pipeline and connect gradually, and the reservoir passes through the pipeline and connects the regenerator, sets up the pump on the pipeline between reservoir and the regenerator, and the regenerator passes through the pipeline and is connected with the pre-heater.

Preferably, the evaporator comprises a cover plate and a bottom plate, the bottom plate is arranged in an evaporator liquid storage tank in the middle of the bottom plate, micro-channels are arranged on two sides of the liquid storage tank, a guide plate is arranged on the upper portion of the micro-channels, one side of the liquid storage tank is connected with an inlet of the evaporator, an outlet is arranged on the other side of the liquid storage tank opposite to the inlet, the outlet is connected with an outflow channel, the outflow channel comprises a first part which is arranged on the outer side of the upper portion of the micro-channels and communicated with the micro-channels, and a second part is arranged on the upper side of the micro-channels perpendicular to the first part and communicated with the outlet.

Preferably, the first portion is a slope structure gradually sloping downward from the outside to the inside. The second part is a slope V-shaped groove which gradually slopes downwards from the outer side to the inner side, and the lowest point is arranged at the outlet position.

Preferably, the liquid storage device comprises a large liquid storage tank and a small liquid storage tank, the top of the small liquid storage tank is communicated with the top of the large liquid storage tank through a top pipeline, the bottom of the small liquid storage tank is communicated with the bottom of the large liquid storage tank through a bottom pipeline, and the top pipeline and the bottom pipeline are respectively provided with an electromagnetic valve. Heating plates and solenoid structures in the small liquid storage tanks. And a porous baffle is arranged at the outlet of the large liquid storage tank. A temperature sensor and a pressure sensor are arranged on the small liquid storage tank to feed back the temperature and the pressure in the tank in real time so as to adjust the heating efficiency of the heating plate and the cooling efficiency of the solenoid. In addition, in order to detect the change of the liquid level in the liquid storage tank in real time, liquid level meters are respectively arranged at the lower parts of the large liquid storage tank and the small liquid storage tank.

Preferably, the condenser comprises a spray tank (left) and a water storage tank (right). The top of the two boxes is provided with an inlet, and the bottom is provided with an outlet. During spraying, gaseous hot fluid is injected into the spray header from the top pipe orifice, is diffused into the box body, is changed into liquid state after exchanging heat with the heat pipe, flows out from the bottom pipe orifice, and enters the next pump driving two-phase circulation. Cold water in the water storage tank body is injected from a top pipe orifice, and hot water is discharged from a bottom pipe orifice. The heat pipe in the spraying box body is obliquely inserted into the water storage tank body at a certain angle, and correspondingly, the spraying direction of the spraying head is also inclined at a certain angle, so that the large end of the heat pipe is fully contacted with sprayed hot fluid during spraying, the purpose of high-efficiency heat exchange is achieved, and meanwhile, the cooling liquid in the heat pipe can flow back to the large end for next circulation under the action of gravity after the small end releases heat and is liquefied. In addition, the heat pipes in the spraying box body are distributed in a staggered mode so as to increase the contact area between the large ends of the heat pipes and sprayed hot fluid.

Compared with the prior art, the invention has the following advantages:

1) The invention designs the novel structure evaporator, the manifold arrangement structure and the micro-channel design in the evaporator prolong the working medium flowing time and the heat exchange area, improve the heat transfer efficiency, optimize the fluid flowing path and reduce the flowing resistance by adding the manifold plate structure and the liquid storage groove, reduce the pump power consumption, ensure the uniform distribution of the working medium and realize the efficient heat dissipation.

2) The invention provides a novel waste heat recovery type pump driving two-phase loop heat pipe, which is based on a mechanical pump driving two-phase fluid loop technology and a phase change heat transfer technology, meets the heat dissipation requirement of high heat flux density, recycles waste heat, and has the advantages of large heat dissipation capacity, low PUE value, wide application, green emission reduction and the like.

3) The supercooled fluid is preheated by the heat regenerator and the preheater before entering the evaporator, so that the supercooled fluid reaches a saturated state. Because the heat absorption capacity of the phase change latent heat is far greater than that of the non-latent heat exchange, the supercooling fluid is heated to the critical temperature of the gasification latent heat, so that the supercooling fluid absorbs the latent heat immediately after entering the evaporator, the rapid heat absorption of the evaporator is realized, and the rapid heat absorption efficiency is improved.

4) The invention designs a novel structure liquid storage device, and innovatively adopts a separated structure. The large liquid storage is responsible for storing working media and has a buffer effect on the fluctuation of the liquid level of fluid in the MPTL loop; the small liquid storage tank is responsible for controlling the pressure, compared with a traditional single liquid storage device, the control part of the separation type liquid storage device is changed from large to small, and the sensing sensitivity and the control accuracy of the system are improved. Compared with the traditional liquid storage device which uses PTC refrigerating sheets for refrigerating, the heat exchange spiral pipe is added in the small liquid storage tank, the spiral pipe passive cooling method can reduce refrigerating electric energy consumption, and can preheat fluid entering the next circulation.

5) The invention designs a novel structure condenser, wherein the condensation waste heat is used as a heat source, circulating water is used as a cold source, the heat absorbing end of a heat pipe is welded with annular fins, the high-efficiency condensation heat release can be realized by combining an atomization spraying device, the heat releasing section of the heat pipe is immersed in a heat storage water tank, and the cold water is heated through heat exchange, so that the waste heat recovery is realized.

6) The invention designs the heat regenerator, adopts a double-way cross countercurrent heat exchange scheme, uses brass as a heat transfer medium, can greatly improve the heat exchange efficiency of a hot working medium and a cold working medium in the heat regenerator while avoiding corrosion phenomena of working medium ammonia and materials, realizes heat exchange of a hot fluid flowing out of an evaporator and a cold fluid flowing out of a pump, and fully utilizes temperature difference to realize heat exchange in advance and primary preheating.

7) The invention designs a novel heat pipe, and the filled microporous capillary core structure can rapidly suck heat transfer working medium in the heat pipe, so that the vaporization and heat exchange rate of the phase change working medium in the heat pipe is higher, and compared with the traditional gravity heat pipe, the heat pipe has higher heat conductivity and stronger reliability.

Drawings

FIG. 1 is a schematic diagram of the overall structure of a loop heat pipe of the present invention.

Fig. 2 is a schematic view of the structure of the evaporator base plate of the present invention.

Fig. 3 is a schematic view of the evaporator of the present invention.

Fig. 4 is a schematic view of the upper plate structure of the evaporator of the invention.

Fig. 5 is a schematic diagram of the reservoir structure of the present invention.

Fig. 6 is a schematic view of the heat pipe structure in the condenser.

Fig. 7 is a schematic view of the heat pipe structure in the condenser.

Fig. 8 is a schematic view of the overall structure of the condenser of the present invention.

Fig. 9 is a schematic diagram of a heat pipe arrangement.

Detailed Description

The following describes the embodiments of the present invention in detail with reference to the drawings.

Herein, "/" refers to division, "×", "x" refers to multiplication, unless otherwise specified.

Fig. 1 illustrates a loop heat pipe system of the present invention. The Loop heat pipe system is a waste heat recovery type pump driving two-phase energy saving system, meets the high heat flux heat dissipation requirement of a server based on a mechanical pump driving two-phase fluid Loop technology (MECHANICALLY PUMPED TWO-phase Loop, MPTL) and a waste heat recovery technology, can recycle waste heat, and has the advantages of high heat dissipation capacity, low PUE value, high flexibility, capability of waste heat recovery and the like.

As shown in fig. 1, a heat pipe system of a waste heat recovery loop comprises a preheater 1, an evaporator 2, a condenser 3, a liquid reservoir 4, a pump 5 and a heat regenerator 6, wherein the preheater 1, the evaporator 2, the condenser 3 and the liquid reservoir 4 are sequentially connected through pipelines, the liquid reservoir 4 is connected with the heat regenerator 6 through pipelines, the pump 5 is arranged on a pipeline between the liquid reservoir 4 and the heat regenerator 6, and the heat regenerator 6 is connected with the preheater 1 through a pipeline. The pump 5 is preferably a mechanical pump.

Referring to fig. 1, when the loop heat pipe system starts to operate, a single-phase cold fluid is driven and controlled by a mechanical pump 5. In operation, the supercooled liquid phase fluid (preferably ammonia) flows into the regenerator 6 under the drive of the mechanical pump 5, the supercooled liquid phase fluid and the two-phase hot fluid flowing out of the evaporator 2 exchange heat in the regenerator 5 once, the single-phase liquid fluid after heat exchange flows into the preheater 1 for secondary heating, the temperature of the single-phase liquid fluid is raised to the saturation temperature, and the liquid fluid is not subjected to phase change.

The fluid reaching the saturation temperature through the preheater 1 flows into the evaporator 2, the fluid changes from a liquid single phase into a vapor-liquid two-phase state after absorbing heat in the evaporator 2, and the fluid absorbs a large amount of heat due to vaporization and increases in dryness. The fluid evaporates and absorbs heat in the evaporator 2, and the absorption and transportation of the target heat are realized through the circulating flow process in the pipeline.

Preferably, the evaporator 2 is in direct coupling contact with a heat source to facilitate further heat absorption.

The fluid absorbed in the evaporator 2 enters the regenerator 7, exchanges heat with the supercooled liquid fluid from the reservoir, then enters the condenser to exchange heat, releases heat and enters the reservoir, thereby completing a cycle.

The invention provides a novel waste heat recovery type pump-driven two-phase flow system, which is based on a mechanical pump-driven two-phase fluid loop technology and a waste heat recovery technology, meets the heat dissipation requirement of high heat flux density, can recycle waste heat, and has the advantages of large heat dissipation capacity, low PUE value, high flexibility, capability of waste heat recovery and the like.

Because the heat absorption time of the fluid in the evaporator is short, the heat absorption speed is slow. The supercooled fluid is preheated by the heat regenerator and the preheater before entering the evaporator, so that the supercooled fluid reaches a saturated state. Because the heat absorption capacity of the phase change latent heat is far greater than the heat exchange capacity of the sensible heat, the supercooling fluid is heated to the critical temperature of the vaporization latent heat, so that the supercooling fluid absorbs heat immediately after entering the evaporator, the rapid heat absorption of the evaporator is realized, and the heat absorption efficiency of the evaporator is improved.

Considering that the preheater consumes a certain amount of electric energy when heating cold fluid, and the two-phase hot fluid flowing out of the evaporator (the fluid with the coexistence of gas and liquid phases flowing out of the evaporator because the liquid ammonia is not necessarily completely vaporized in the evaporator) has larger heat, the team skillfully makes the pipeline of the two-phase hot fluid contact with the pipeline of cold fluid to exchange heat, and the cold fluid is heated by the heat of the hot fluid in advance, so that the electricity consumption of the preheater is reduced, the effect of condensing the hot fluid in advance is also realized, the process is called as backheating, and the corresponding device is called as backheating.

The two-phase fluid from the regenerator 6 enters the condenser 3 for heat exchange. When the condenser 3 works, the two-phase fluid is changed from a gas-liquid two-phase state to a liquid single-phase state, and the dryness is reduced. Meanwhile, most of the heat released by the condensation of the thermal fluid is transferred to the energy storage water tank 3-3 by the heat pipe fin array 3-1 and is stored by circulating water, so that the waste heat can be recycled, and the waste heat pollution and secondary carbon emission can be effectively reduced.

The condensed fluid flows into the liquid storage device 4, the liquid storage device 4 regulates and controls the flow and the pressure, the pressure in the device is kept constant, and the cold fluid is provided with working medium circulation driving force by the mechanical pump 5 so as to enter the heat regenerator 6 for the next working cycle, so that the heat dissipation function with high heat flux density is realized in a reciprocating manner.

Preferably, a part of the fluid from the condenser is directly driven by the pump 5 into the regenerator 6 for the next cycle, and a part is stored in the reservoir 4, so that the circulating fluid is driven by the pump into the cycle when it is reduced.

Preferably, the evaporator adopts a manifold type micro-channel heat sink structure.

As shown in fig. 2-4, the evaporator 2 comprises a cover plate and a bottom plate, and as shown in fig. 3, the bottom plate is provided with a guide plate 2-1, a liquid storage tank 2-2, a gas-liquid outlet 2-3, a side slope 2-4, a micro-channel 2-5, a liquid inlet 2-6, a slope V-shaped groove 2-7 and an exhaust channel 2-8. The bottom plate comprises an evaporator liquid storage tank 2-2 arranged in the middle of the bottom plate, micro-channels 2-5 are arranged on two sides of the liquid storage tank 2-2, and a guide plate 2-1 is arranged on the upper part of the micro-channels 2-5. The guide plate plays a role in changing the flow path of the gas-phase working medium, the liquid working medium becomes a gaseous state after being heated and evaporated, and the gas-phase working medium rises after being heated, but due to the blocking effect of the guide plate, the gas-phase working medium cannot be discharged from the top layer in the evaporator and can only be discharged from the micro-channel below the guide plate. Preferably, the baffle is welded directly to the upper portion of the microchannel. One side of the liquid storage tank is connected with an inlet 2-6 of the evaporator, an outlet 2-3 is arranged on the other side opposite to the inlet, the outlet 2-3 is connected with an outflow channel, the outflow channel comprises a first part 2-4 which is arranged on the outer side of the upper part of the micro-channel and communicated with the micro-channel, a second part is arranged at one end of an outlet of the bottom plate and extends along the end part of one end of the outlet, the end parts on two sides of the second part are communicated with the first part, and the middle part of the second part is communicated with the outlet 2-3.

The location where the microchannels communicate with the first section 2-4 is provided at the end of the first section remote from the second section. Through this setting, avoid the excessive entering second part of overflow liquid, avoid the excessive water of the vapour-water mixture of output.

The baffle 2-1 is arranged close to the first part, and a part of the micro-channel which is not covered by the baffle is reserved between the first part and the baffle, and the part of the micro-channel forms an exhaust channel 2-8 for discharging steam.

In the evaporator structure, fluid flows into the liquid storage tank 2-2 vertical to the micro-channel direction, is split to two sides, and flows into the micro-channel to be converged near the outlet. The flow channel design makes the flow channel in the heat sink have strong cycle repeatability, and the original long straight micro channel is segmented into short and small bent micro channel units. The heat-exchanging device has the characteristics of small heat resistance, small inlet and outlet pressure loss, uniform heat exchange, compact structure, suitability for heat dissipation of electronic elements and the like.

The second portion is not in communication with the microchannel and the reservoir. The gas flows out from the micro channel at the other side through the diversion trench and enters the second part, the effect of non-communication is to prevent the liquid working medium from directly entering the second part to block the gas channel, and prevent the liquid working medium from being discharged without absorbing heat, the liquid is accumulated in the first part after overflowing the micro channel and then flows to the outlet 2-3 through the second part, the liquid volume is not much, and most of the liquid is gasified, so the length of the first part is not required to be long.

The first portion is disposed between the inlet and the outlet at a position near the outlet and has a length of 1/3 to 1/4 of the distance between the inlet and the outlet. By setting the distance, the vapor can be generated as much as possible after more liquid absorbs heat sufficiently, and a large amount of liquid is prevented from entering the first part.

Preferably, the first portion is an inclined structure, and gradually becomes deeper from the outside to the inside. The second part is a slope V-shaped groove 2-7, which is gradually deeper and deeper from two ends to the center, and the lowest point is arranged at the outlet position. Preferably, the bottom wall of the first portion is inclined downwardly in the direction of the second portion to ensure that liquid can enter the second portion.

Preferably, the V-groove configuration is 145-155.

The slope type V-shaped groove 2-7 shown in the figure 3 is adopted to realize automatic flow guiding of liquid and discharge of residual liquid with maximum efficiency, a V-shaped angle design of about 150 degrees is matched with an outlet with the diameter of 7mm, so that a better liquid discharge rate can be achieved, the outlet is in tangential relation with the bottom end of the V-shaped groove 2-7 shown in the figure 3, the smooth transition reduces the flowing resistance of the liquid to the minimum, the residual liquid of the device is ensured to be discharged in time, the internal blockage caused by excessive accumulation of the liquid is prevented, and the unique V-shaped groove 2-7 shown in the figure 3 is beneficial to the stable operation of the protection device.

The liquid ammonia flows into the evaporator liquid storage tank 2-2 through the pipeline, the liquid level is gathered in the liquid storage tank 22 in fig. 2 and rises, after the liquid level rises to a certain height, the liquid ammonia diffuses to two sides and flows into the micro-channels 2-5 in fig. 2 (in this case, the flow quantity of the liquid flowing into each micro-channel in unit time is equal, the uniform flow distribution is beneficial to improving the heat absorption efficiency of the evaporator), as the bottom of the micro-channels 2-5 in fig. 2 is a heat source, the heat can be timely transmitted to the liquid heat absorption fluid through the evaporator, at this time, the fluid begins to absorb heat, when the temperature of the fluid reaches the boiling point, vaporization begins, the fluid is converted from the liquid state to the gaseous state, the gaseous state fluid is heated and rises, the gas transmission path is changed under the action of the flow guide plate 2-1 in fig. 2, the flow guide plate plays the role of changing the gas phase working medium flow path, the liquid state is heated and evaporated, but the gaseous state working medium is heated and rises, but can not be discharged from the top layer inside the evaporator due to the blocking effect of the guide plate, and can only be discharged from the micro-channel below the guide plate. When the liquid fluid absorbs heat continuously and the vaporization process is carried out continuously, more and more gas is accumulated in the cavity of the manifold type evaporator, the gas moves downwards under the action of the guide plate 2-1 in fig. 2, passes through the guide plate 2-1 and moves upwards to enter the exhaust channel 2-8, then steam enters the outflow channel and finally is discharged from the outlet. The gas transmission path of the evaporator is different from the traditional micro-channel bottom plate, and can effectively reduce the gas flow resistance and simultaneously take away more heat in unit time. The liquid, which has overflowed the microchannels, accumulates in the first part and then flows through the second part to the outlets 2-3, the liquid volume is not very large and most has evaporated, so that the length of the first part does not need to be very long. The microchannel communicates with the first portion such that liquid spilled over after heat exchange enters the first portion.

The fluid ammonia is changed into a two-phase state after passing through the micro-channel 2-5 in the figure 3, and the fluid ammonia is gathered and poured into the slope V-shaped channel 2-7 in the figure 3, and the V-shaped channel with the slope has a guiding function, so that the two-phase fluid ammonia automatically flows along the channel towards the outlet direction, is gathered and stored at the outlet; meanwhile, the liquid level can reach the highest through the V-shaped channel, liquid fluid can smoothly flow into the outlet pipeline under the minimum driving force, the discharge efficiency of redundant liquid fluid is maximized, the redundant liquid fluid is discharged out of the evaporator through the outlet and flows into the outlet pipeline.

The slope V-shaped groove 2-7 of the design figure 3 has the significance of reducing the driving force required by liquid converging to the outlet and reducing the energy consumption required by the operation of the device; meanwhile, the V-shaped grooves 2-7 in the figure 3 can automatically collect and store the liquid in the middle area, so that the maximum liquid discharge efficiency is achieved, the liquid is prevented from flowing back due to excessive collection, and the stable operation of the protection device is facilitated.

Preferably, the cover plate is carved with a channel, which is beneficial to matching with the bottom plate and ensures good sealing performance.

Preferably, the heat source to which the evaporator is thermally connected is an electronic device. And the heat dissipation requirement of the integrated electronic device with high heat flux density is met.

The liquid storage device plays roles of fluid storage, supply, precise temperature control and gas-liquid separation. In a pump-driven two-phase fluid circuit, fluid flows in an evaporator and a reservoir are in a two-phase saturated state, and the saturated pressure and the saturated temperature of the fluid flows are in a linear relation. The liquid storage device maintains the constant saturation pressure in the whole liquid storage device by controlling the temperature in the small liquid storage tank, thereby ensuring that the fluid in the evaporator is stabilized at the corresponding saturation temperature. The liquid storage device is in a two-phase state, the liquid storage device plays a role in gas-liquid separation, the phase change of working media exists in a loop, the phase change can affect the volume of the working media, the gasification volume is increased, the liquefaction volume is reduced, the liquid storage device is required to buffer, when too much working media are not needed in the loop, redundant working media are stored in the liquid storage tank, and when the working media come out of the condenser, if the working media are in the two-phase state, the liquid storage device can perform gas-liquid separation through the porous partition plate.

Preferably, as shown in fig. 5, the liquid storage tank 4 is divided into a large liquid storage tank 4-3 and a small liquid storage tank 4-7, the top of the small liquid storage tank 4-7 is communicated with the top of the large liquid storage tank 4-3 through a top pipeline, the bottom of the small liquid storage tank 4-7 is communicated with the bottom of the large liquid storage tank 4-7 through a bottom pipeline, and the top pipeline and the bottom pipeline are respectively provided with an electromagnetic valve 4-1.

The large liquid storage tank stores a large amount of liquid fluid, so that fluid exchange with the main loop can be realized. When the liquid fluid is filled from the outside, the liquid fluid is continuously filled into the large reservoir from the filling port 4-2 (of fig. 5) at the upper end of the large reservoir, and thus the whole circuit is filled. In a pump-driven two-phase fluid circuit, the saturation pressure in the reservoir determines the saturation temperature at which the fluid changes phase, and in order to maintain the saturation temperature, the temperature of the reservoir needs to be controlled to maintain the saturation pressure therein. In consideration of the relative difficulty in directly changing the temperature of the liquid in the large liquid storage tank, a team introduces the small liquid storage tank outside the large liquid storage tank, and the two tanks are communicated, and the pressure in the large liquid storage tank is indirectly controlled by controlling the temperature and the pressure in the small liquid storage tank, so that the saturation pressure is kept constant. The top and bottom of the big liquid storage tank and the small liquid storage tank are respectively connected by pipelines, and an electromagnetic valve (shown in figure 5) 4-1 is arranged between the two pipelines. Before the system starts to work, the lower electromagnetic valve is opened, and the upper electromagnetic valve is closed; after the system starts to work, the upper electromagnetic valve is opened to ensure that the internal pressure of the two liquid storage tanks is equal, and the lower electromagnetic valve is closed to separate the liquid phases in the two tanks.

Heating plate and solenoid structure in the little liquid storage pot: to control the temperature within the small reservoir (of fig. 5) 4-7, a heating rod (of fig. 5) 4-6 and a solenoid (of fig. 5) 4-8 are mounted inside the small reservoir to achieve heating and cooling, respectively. Because the active cooling of the liquid in the small liquid storage tank needs a certain energy consumption, and the existing supercooled fluid in the loop can meet the cooling requirement of the small liquid storage tank, a team decides to introduce a part of supercooled fluid condensed by the condenser 3 into the solenoid, the part of supercooled fluid flows through the solenoid and returns to the main loop, and the liquid in the tank is cooled by utilizing the temperature difference of the supercooled fluid and the liquid in the small liquid storage tank, so that the extra energy consumption required by refrigeration is saved. The adjustment of the cooling efficiency is achieved by controlling the flow of subcooled fluid through a valve at the solenoid inlet.

Porous partition plate of large reservoir outlet: the space (of figure 5) in the large liquid storage tank (4-3) except for the liquid fluid is filled with the gas phase working medium, so as to realize gas-liquid separation and prevent the gas phase working medium in the liquid storage tank from entering the main loop to cause cavitation of the mechanical pump, a sintered porous partition board (of figure 5) 4-11 is arranged at the outlet of the large liquid storage tank, and capillary holes on the porous partition board can effectively block the gas phase working medium while flowing the liquid fluid and prevent the gas phase working medium from entering the main loop.

Sensor arrangement: a temperature sensor (of fig. 5) 4-9 and a pressure sensor (of fig. 5) 4-4 are installed on the small reservoir (of fig. 5) 4-3 to feed back the in-tank temperature and pressure in real time in order to adjust the heating efficiency of the heating rod (of fig. 5) 4-6 and the cooling efficiency of the solenoid (of fig. 5) 4-8. Furthermore, in order to detect the change of the liquid level in the liquid storage tank in real time, liquid level gauges (of fig. 5) 4-5 and heating bars 4-6 are installed at the lower parts of the large liquid storage tank (of fig. 5) 1-3 and the small liquid storage tank (of fig. 5) 4-7, respectively.

When the fluid comes out of the condenser, the reservoir can be vapor-liquid separated by the porous partition, if in a two-phase state. Preferably, the cooled liquid ammonia first enters the reservoir and is driven by the mechanical pump to perform the next cycle.

Preferably, as shown in fig. 8, the condenser includes a shower tank (left) and a water storage tank (right). The top of the two boxes is provided with an inlet, and the bottom is provided with an outlet. During spraying, gaseous hot fluid is injected into the spray header from the top pipe orifice, is diffused into the box body, is changed into liquid state after exchanging heat with the heat pipe, flows out from the bottom pipe orifice, and enters the next pump driving two-phase circulation. Cold water in the water storage tank body is injected from a top pipe orifice, and hot water is discharged from a bottom pipe orifice. The heat pipe in the spraying box body is obliquely inserted into the water storage tank body at a certain angle, and correspondingly, the spraying direction of the spraying head is also inclined at a certain angle, so that the large end of the heat pipe is fully contacted with sprayed hot fluid during spraying, the purpose of high-efficiency heat exchange is achieved, and meanwhile, the cooling liquid in the heat pipe can flow back to the large end for next circulation under the action of gravity after the small end releases heat and is liquefied. In addition, the heat pipes in the spraying box body are distributed in a staggered mode so as to increase the contact area between the large ends of the heat pipes and sprayed hot fluid.

When the heating value of the heat source is increased, more liquid-phase fluid in the evaporator 2 is converted into gas phase, the volume of the gas phase is increased, the pressure in the loop is higher than the saturation pressure, at the moment, redundant liquid-phase fluid in the loop flows into the large liquid storage tank (4-3 in fig. 5) for storage, meanwhile, supercooled fluid in the solenoid (4-8 in fig. 5) cools liquid in the small liquid storage tank (4-7 in fig. 5), so that the integral pressure of the two liquid storage tanks is reduced, and the pressure in the loop is immediately reduced to the saturation pressure; conversely, when the heating value of the heat source is reduced, the heating value is reduced, a small amount of liquid phase fluid in the evaporator is converted into gas phase, the volume of the gas phase is reduced, the pressure in the loop is lower than the saturation pressure, at the moment, insufficient fluid in the loop can be supplemented by the large liquid storage tank, meanwhile, the heating sheets (shown in figure 5) 4-10 heat the liquid in the small liquid storage tank, so that the integral pressure of the two liquid storage tanks is increased, and the pressure in the loop is immediately increased to the saturation pressure. When the reservoir supplements the fluid in the main circuit, the porous partition plates (4-11 of fig. 5) at the outlet of the reservoir can block the gas-phase working medium in the tank to prevent the gas-phase working medium from entering the main circuit to cause cavitation of the mechanical pump.

Preferably, flat tubes are provided in the regenerator 6, and fluid from the evaporator flows through the flat tubes. The flat tube is provided with a fin array with a fusiform structure. The pin-fin array is described in the prior application numbers (CN 202210267306.8, CN202210267339.2, CN202210267340.5, CN 202210267351.3), all features of which are incorporated herein by reference. The novel fusiform structure fin is arranged, so that fluid can flow along the fin, and the heat exchange efficiency is improved.

The fin arrays are a plurality of, and two adjacent fin arrays are connected end to end. Each fin array is divided into multiple layers, each array including a central fin and multiple layers of peripheral fins surrounding the central fin, each layer of fins being a fusiform structure. By providing multiple layers, the fluid is allowed to flow sufficiently therein for heat exchange.

The plurality of fin arrays form a group, the head of the first shuttle of each group being opposite to the fluid direction of the liquid (facing the fluid flow direction), the tail of the first shuttle being connected to the head of the second shuttle, and so on, thereby forming a group. Through setting up the multilayer for the fluid can fully flow heat transfer therein, and the flow path of fluid carries out frequent flow and volume change along the shuttle shape along with flowing constantly moreover, further improves heat transfer efficiency.

Both the leading and trailing portions of the shuttle are the tips. The tip angle of the head part of the fusiform structure is smaller than the tip angle of the tail part. By adopting the structure, the fluid can be slowly diffused along the shape of the shuttle, the characteristic of low heat exchange effect caused by rapid diffusion is avoided, the heat exchange is promoted, meanwhile, the guiding of the fluid is promoted, the fluid is further matched with the capillary structure in the front, and the evaporation efficiency is improved.

Preferably, the line connecting the center fins of each group is the same as the fluid flow direction.

Preferably, the plurality of sets of fin arrays are arranged in parallel.

Preferably, the fin is an elastic component, the elastic component can enable the heat conductor to be washed when fluid flows, the fin can pulsate and swing, and therefore scale removal is promoted, turbulent flow effect is caused by vibration, and heat transfer can be enhanced.

Preferably, the elasticity of the fins decreases and increases in the direction of fluid flow in the flat tube. Because along with the research, along with the fluid gets into the flat tube, because the sudden increase of volume, pressure diminishes for the partial liquid that partly carries also constantly forms the vapor, thereby makes the impact increase, be difficult for the scale formation, consequently set up elasticity and begin to reduce gradually, along with follow-up heat transfer condensation, the fluid is easier to scale deposit, moreover along the scale formation degree of fluid flow direction is more serious more and more, consequently through setting up elasticity degree constantly increasing, has reached further scale removal strengthening heat transfer purpose, reduces the heat conductor of great elasticity, reduce cost. Through the arrangement, heat exchange and descaling can be further and rapidly realized, and meanwhile, the cost can be saved, so that the best effect and the lowest cost are achieved.

It is further preferred that the thermal conductor has a smaller and smaller amplitude of elasticity and a larger amplitude of subsequent increase in the direction of fluid flow within the flat tube. The change is found according to the research, accords with the scaling rule, and can further reduce the cost, improve the heat exchange efficiency and reduce the scaling. So that the best effect and the lowest cost are achieved.

The condenser in FIG. 8 consists of a spray tank body 3-2 and a heat storage tank body 3-4, the water in the heat storage tank body 3-4 on the right side of FIG. 8 absorbs heat and warms up to achieve the purpose of storing heat, meanwhile, the original gas phase in the two-phase fluid in the spray tank body 3-2 on the left side of FIG. 8 is liquefied by heat release and condensed into a liquid phase, and the liquid phase fluid downwards enters the liquid storage tank 4 and the filter return pipeline in FIG. 1 based on the principle that the liquid phase of a substance is higher than the gas phase density, so that the purpose of recovering low-grade waste heat is achieved. The circulating flow of fluid between the evaporator 2 and the condenser 3 in fig. 1 is mainly powered by the pump 5, and the reciprocating circulation realizes efficient heat exchange.

The condensing unit comprises a spraying box body and a water storage box body. The top of the two boxes is provided with an inlet, and the bottom is provided with an outlet. During spraying, gaseous hot fluid is injected into the spray header from the top pipe orifice, is diffused into the box body, is changed into liquid state after exchanging heat with the heat pipe, flows out from the bottom pipe orifice, and enters the next pump driving two-phase circulation. Cold water in the water storage tank body is injected from a top pipe orifice, and hot water is discharged from a bottom pipe orifice. The heat pipe in the spraying box body is obliquely inserted into the water storage tank body at a certain angle, and correspondingly, the spraying direction of the spraying head is also inclined at a certain angle, so that the large end of the heat pipe is fully contacted with sprayed hot fluid during spraying, the purpose of high-efficiency heat exchange is achieved, and meanwhile, the cooling liquid in the heat pipe can flow back to the large end for next circulation under the action of gravity after the small end releases heat and is liquefied. In addition, the heat pipes in the spraying box body are distributed in a staggered mode so as to increase the contact area between the large ends of the heat pipes and sprayed hot fluid.

The heat pipe unit comprises an evaporation end, a condensation end 3-1-1, a silica gel gasket 3-1-2, a fastening plate 3-1-3, a heat conduction fin 3-1-4, a heat pipe plug 3-1-5, a capillary core 3-1-6 and a heat pipe shell 3-1-7. Wherein the heat pipe shell between the evaporation end and the condensation end is provided with a fastening plate, the upper side of the fastening plate is provided with a silica gel gasket, and the silica gel gasket is tightly pressed by the fastening plate to perform sealing action.

The heat pipe comprises a large end and a small end, the pipe diameter and the length of the large end are larger than those of the small end, the large end of the heat pipe is inserted into the spraying box body, and the small end of the heat pipe is inserted into the water storage tank body. Preferably, the large end is externally provided with fins. Through setting up the fin, can satisfy the equilibrium of heat absorption exothermic better. Through setting up big end and tip, can make both sides heat absorption and exothermic even balance, avoid one side heat absorption too slow, the opposite side is exothermic too fast, avoids the dry and damage of heat pipe.

After the gas-phase hot fluid flows into the spray header, the spray header uniformly diffuses the hot gas to the heat pipe fins, and after the heat conduction fins at the large end are in contact with the hot gas, the heat of the hot gas is conducted to the heat conduction fins, so that the heat is conducted to the inside of the heat pipe body. The two-phase fluorinated coolant is contained in the heat pipe, so that the coolant absorbs heat and is vaporized, gas is heated and is conveyed to the small end of the heat pipe, the small end of the heat pipe is surrounded by external cold water at the moment, the temperature difference is large, gas heat is conducted on the outer side wall surface, the water absorbs heat and is heated, the hot gas releases heat and is cooled to be condensed, and the condensed liquid fluorinated coolant flows back to the large end of the heat pipe along the pipe wall, so that reciprocating circulation heat dissipation is realized.

In order to improve the heat absorption efficiency of two-phase fluid in the heat pipe, long capillary cores 3-1-6 are arranged in the large end in a staggered mode, when the fluid is guided to flow to the evaporation end, the effective heat exchange area is utilized to the maximum extent, the capillary cores are manufactured by adopting a metal sintering method, and metal powder and pore-forming agent with the ratio of 1:1 are filled in a special die. The capillary core provides a large number of micropores, can absorb two-phase fluid in a shorter time and rapidly make the two-phase fluid absorb heat and change phase, and greatly improves the heat exchange efficiency of the heat pipe.

The external thread and the internal thread at the position (close to the silica gel gasket) of the small end of the part a and the position (close to the silica gel gasket) of the part b are convenient to detach, and the external thread at the small end of the heat pipe at the part a is screwed with the side wall of the water tank and is matched with the fastening plate and the silica gel gasket to realize good tightness; b is arranged on the inner thread at the tail part of the large end of the heat pipe and the outer thread at the outer wall of the heat pipe plug, so that the two-phase coolant in the heat pipe can be conveniently supplemented or replaced, and the capillary core can be conveniently replaced and repaired.

While the invention has been described in terms of preferred embodiments, the invention is not so limited. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention, and the scope of the invention should be assessed accordingly to that of the appended claims.

Claims (6)

1. The evaporator comprises a cover plate and a bottom plate, wherein the bottom plate comprises a guide plate, a liquid storage tank, a gas-liquid outlet, a side slope, a micro-channel, a liquid inlet and a slope V-shaped groove, the liquid storage tank is arranged in the middle of the bottom plate, the micro-channel is arranged on two sides of the liquid storage tank, the guide plate is arranged at the upper part of the micro-channel, one side of the liquid storage tank is connected with the inlet of the evaporator, the outlet is arranged on the other side opposite to the inlet, the outlet is connected with an outflow channel, the outflow channel comprises a first part which is arranged at the outer side of the upper part of the micro-channel and is communicated with the micro-channel, a second part is arranged at one end of the outlet of the bottom plate and extends along the end part of one end of the outlet, the end parts on two sides of the second part are communicated with the first part, and the middle part of the second part is communicated with the outlet; the first part is a side slope, and the first part is gradually deeper and deeper from the outer side to the inner side; the second part is a slope V-shaped groove; gradually deepening from two ends to the center, wherein the lowest point is arranged at the outlet position; the micro channel is arranged at the end position of the first part far away from the second part; the guide plate is arranged at a position close to the first part, and a part of micro-channel which is not covered by the guide plate is reserved between the first part and the guide plate, and the micro-channel forms an exhaust channel for discharging steam; the second portion is not in communication with the microchannel and the reservoir.

2. The evaporator of claim 1, wherein the first portion is disposed between the inlet and the outlet at a position near the outlet and has a length of 1/3 to 1/4 of the distance between the inlet and the outlet.

3. The evaporator of claim 2, wherein the bottom wall of the first portion is sloped downwardly toward the second portion to ensure that liquid can enter the second portion.

4. The evaporator of claim 2, wherein the V-groove configuration is 145-155 °.

5. The evaporator of claim 1, wherein the liquid ammonia flows into the evaporator liquid storage tank through a pipeline, the liquid level is gathered in the liquid storage tank to rise, when the liquid level rises to a certain height, the liquid ammonia diffuses to two sides and flows into the micro-channel, the bottom of the micro-channel is a heat source, at the moment, the fluid starts absorbing heat, when the temperature of the fluid reaches a boiling point, the fluid starts vaporizing, the fluid is converted from a liquid state to a gaseous state, the gaseous fluid is heated to rise, a gas transmission path is changed under the action of a guide plate, the guide plate plays the role of changing a gas phase working medium flow path, the liquid working medium is heated to be vaporized and then becomes a gaseous state, and the gas phase working medium is heated to rise, but due to the blocking action of the guide plate, the gaseous wages can not be discharged from the top layer in the evaporator, and can only be discharged from a micro-channel below the guide plate; when the liquid fluid continuously absorbs heat and the vaporization process is continuously carried out, more and more gas is accumulated in the evaporator cavity, the gas moves downwards under the action of the guide plate, passes through the guide plate and then moves upwards to enter the exhaust channel, then steam enters the outflow channel and finally is discharged from the outlet.

6. The heat pipe system of the waste heat recovery loop comprises a preheater, an evaporator, a condenser, a liquid reservoir, a pump and a heat regenerator, wherein the preheater, the evaporator, the condenser and the liquid reservoir are sequentially connected through pipelines, the liquid reservoir is connected with the heat regenerator through a pipeline, the pump is arranged on the pipeline between the liquid reservoir and the heat regenerator, and the heat regenerator is connected with the preheater through a pipeline; the evaporator is an evaporator according to any one of claims 1 to 5.