Experimental equipment for homogeneous and non-equilibrium condensation and liquefaction of hydrogen

Abstract

The utility model discloses experimental equipment for homogeneous and unbalanced condensation and liquefaction of hydrogen, and solves the technical problem that the hydrogen liquefaction yield cannot be improved as expansion parameters of hydrogen and the structure of a hydrogen supersonic liquefaction expansion machine cannot be explored in the prior art. The experimental equipment comprises a hydrogen supply unit, a pre-cooling unit and a spray pipe for simulating a hydrogen supersonic liquefaction expansion machine which are connected in sequence, the gas inlet side of the spray pipe is intermittently connected with the pre-cooling unit, the gas outlet side of the spray pipe is connected with a circulating unit, and the liquid outlet side of the spray pipe is connected with a measuring unit and a collecting unit. The non-equilibrium condensation liquefaction phenomenon of hydrogen is simulated by using the spray pipe, and the humidity in the spray pipe is measured through the optical measurement module, so that the hydrogen liquefaction efficiency is measured; the relationship among the hydrogen temperature, the hydrogen pressure, the longitudinal section of the spray pipe and the hydrogen liquefaction efficiency is obtained by combining simulation verification, so that the structural improvement of the hydrogen supersonic liquefaction expansion machine under different hydrogen flow working conditions can be guided, and the liquid hydrogen yield is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of hydrogen liquefaction, in particular to experimental equipment for hydrogen homogeneous non-equilibrium condensation and liquefaction. Background Art

[0002] Hydrogen energy is one of the important bridges for the transition from fossil energy to renewable energy. The density of liquid hydrogen is much higher than that of gaseous hydrogen, so liquid hydrogen can provide higher energy density under the same volume. The current hydrogen liquefaction system uses a high-speed rotating turbine expander as an expansion refrigeration device. Its mechanical moving parts have hidden dangers of unsafe and unstable operation. In addition, the turbine expander has a complex structure, is difficult to process, and has high maintenance costs. In addition, the turbine expander cannot work with liquid during operation, otherwise it will cause serious problems such as blade damage.

[0003] Therefore, the Chinese invention patent with an application announcement date of 2021.11.26 and an application announcement number of CN 113701450 A discloses a hydrogen supersonic two-phase direct expansion liquefaction system and a hydrogen liquefaction device, including a liquefaction pipeline and a precooling pipeline. The gaseous hydrogen in the liquefaction pipeline flows through the hydrogen compressor, the first heat exchanger to the first supersonic liquefaction expander in sequence. The liquid outlet side of the first supersonic liquefaction expander is connected to a liquid hydrogen storage tank, and the gas outlet side of the first supersonic liquefaction expander flows to the first heat exchanger to reach the inlet side of the hydrogen compressor. The precooling pipeline of the above technical solution is divided into a first precooling pipeline and a second precooling pipeline to precool the hydrogen in sequence, and the gaseous hydrogen in the liquefaction pipeline is quickly cooled by precooling, and then a supersonic liquefaction expander is used as an expansion refrigeration device to realize the expansion of hydrogen in the two-phase region. However, the technology of supersonic liquefaction expander as an expansion refrigeration device is not yet mature, and the expansion parameters of hydrogen and the structure of the supersonic liquefaction expander directly affect the liquefaction efficiency of hydrogen. In order to further improve the yield of liquid hydrogen, further research is needed on the expansion parameters of hydrogen and the structural design of hydrogen supersonic liquefaction expander. Utility Model Content

[0004] In view of the deficiencies in the above-mentioned background technology, the utility model proposes an experimental device for the homogeneous non-equilibrium condensation and liquefaction of hydrogen. The technical problem to be solved is that the existing technology is unable to explore the expansion parameters of hydrogen and the structure of the hydrogen supersonic liquefaction expander, and thus is unable to improve the technical problem of hydrogen liquefaction yield.

[0005] The technical solution of this application is:

[0006] The experimental equipment for hydrogen homogeneous non-equilibrium condensation and liquefaction comprises a hydrogen supply unit, a precooling unit and a nozzle simulating a hydrogen supersonic liquefaction expander which are connected in sequence, the air inlet side of the nozzle is intermittently connected to the precooling unit, the air outlet side of the nozzle is connected to the circulation unit, the liquid outlet side of the nozzle is connected to the measuring unit and the collecting unit, the cross section of the nozzle is rectangular, and the left and right sides of the nozzle are provided with light-transmitting panels connected to the measuring unit along the hydrogen flow direction, the precooling unit comprises a hydrogen pipeline, a first cooling medium pipeline and a second cooling medium pipeline, the hydrogen pipeline comprises a first hydrogen compressor, a second heat exchanger, a third heat exchanger, a second hydrogen compressor and a temperature and pressure sensor, the first cooling medium pipeline comprises a first cooling medium compressor, a second heat exchanger and a supersonic liquefaction expander, a third heat exchanger, and the second cooling medium pipeline comprises a second heat exchanger.

[0007] The hydrogen supply unit of the technical solution can provide hydrogen, the precooling unit can compress and cool the hydrogen, a valve 1 is arranged between the hydrogen supply unit and the precooling unit, a nozzle is used to simulate a hydrogen supersonic liquefaction expander, and hydrogen reaching a target temperature and a target pressure is expanded and liquefied to obtain liquid hydrogen. The air intake method, liquid discharge method, and air discharge method of the nozzle are the same as those of the hydrogen supersonic liquefaction expander. A valve 2 is arranged between the air intake side of the nozzle and the precooling unit. The test unit and the collection unit are arranged along the flow direction of the hydrogen, the test unit is connected to both sides of the nozzle, and the collection unit is connected to the end of the nozzle. The measuring unit can perform a humidity test on the liquid hydrogen in the nozzle. The higher the humidity, the higher the hydrogen liquefaction efficiency and the higher the liquid hydrogen yield. The nozzle includes a contraction section and an expansion section. The expansion section to the outlet is the liquid outlet side. A vortex generator that is the same as the hydrogen supersonic liquefaction expander is arranged on the air inlet side of the nozzle. Hydrogen and liquid hydrogen are separated by centrifugal force and collected separately. Liquid hydrogen flows to the end of the liquid outlet side of the nozzle under the action of centrifugal force. The collecting unit collects the liquid hydrogen at the end of the liquid outlet side. The unliquefied hydrogen is discharged from the air outlet side of the nozzle and is recovered by the circulation unit and flows back into the precooling unit.

[0008] Specifically, the nozzle should be cylindrical with a smooth and frictionless interior. The upper and lower sides of the nozzle are arc panels that first contract and then expand. The upper and lower arc panels of the nozzle and the left and right light-transmitting panels together form a sealed tube, leaving only the inlet and outlet for hydrogen to flow inside. The shape of the nozzle first contracts and then expands along the flow direction of hydrogen, which makes it easier for hydrogen to reach a transcritical state and then a non-equilibrium condensation process occurs. The rectangular cross-section makes it easy for the nozzle to connect to the measurement unit. The light-transmitting panel can be applied to a variety of optical measurement modules. The light-transmitting panels are arranged on the left and right to facilitate the connection of the measurement unit.

[0009] Specifically, the second cooling medium is introduced into the second cooling medium pipeline, the first cooling medium is introduced into the first cooling medium pipeline, the first cooling medium flows through the first cooling medium compressor and the second heat exchanger, the second cooling medium cools down the first cooling medium in the second heat exchanger, the first cooling medium after once cooling continues to flow through the supersonic liquefaction expander for expansion and liquefaction, hydrogen is introduced into the hydrogen pipeline, the hydrogen is compressed by the first hydrogen compressor in sequence, heat exchanged and cooled with the second cooling medium in the second heat exchanger, heat exchanged and cooled with the liquefied first cooling medium in the third heat exchanger, and then compressed for the second time by the second hydrogen compressor, and the temperature and pressure sensor is used to monitor whether the hydrogen reaches the target temperature and target pressure. If the target temperature and target pressure are reached, valve two is opened to allow the hydrogen to enter the nozzle through the air intake side. If the target temperature and target pressure are not reached, the hydrogen is compressed and cooled to the target temperature and target pressure by adjusting the parameters of the first hydrogen compressor and the second hydrogen compressor and replacing the first cooling medium and the second cooling medium.

[0010] Preferably, the liquid outlet side of the nozzle includes overflow holes evenly spaced along the upper and lower side walls of the nozzle, and each overflow hole is connected to a collection unit. The liquid outlet side of the nozzle includes a nozzle and overflow holes located on the upper and lower side walls of the nozzle. After hydrogen flows through the air inlet side, it flows along the nozzle. Due to the shape of the nozzle that first contracts and then expands, the volume of hydrogen is first compressed and then expanded. In this process, hydrogen is liquefied. The overflow hole is set at the end of the hydrogen flow direction, and the outlet direction of the overflow hole matches the centrifugal force direction. The sizes of the overflow holes are the same, and the outlet direction of the overflow hole simulates the liquid outlet side direction of the hydrogen supersonic liquefaction expander. The liquid hydrogen obtained by expansion and liquefaction in the nozzle flows to the collection unit through the overflow hole.

[0011] Preferably, the measuring unit includes a humidity measuring module, which is arranged on a sliding mechanism, and the sliding direction of the sliding mechanism is parallel to the nozzle. The humidity measuring module measures the diameter and number of condensed droplets by the extinction method. The humidity measuring module includes an optical fiber and a laser emission box connected by electrical signals, and the optical fiber is slidably connected to the light-transmitting panels on the left and right sides of the nozzle through a sliding mechanism. The humidity measurement measures the diameter and number of condensed droplets by the extinction method, and then converts them to obtain the humidity. The hydrogen temperature and hydrogen pressure on the air inlet side of the nozzle are changed in turn. In each test, the optical fiber is fixed at different positions of the nozzle for multiple measurements to obtain the hydrogen expansion conditions when the liquefaction efficiency is the highest.

[0012] Preferably, the measuring unit includes a density measuring module, the measuring direction of which is perpendicular to the light-transmitting panel of the nozzle. The density measuring module adopts optical measurement, and the density measuring module records the change process of the refractive index in the nozzle in real time through the shearing interference method, obtains the density through conversion, and outputs clear patterns at each moment for analyzing the starting position of condensation.

[0013] Preferably, the sliding mechanism includes a movable bracket slidably connected to the light-transmitting panel, and the humidity measuring module is fixedly connected to the movable bracket. The sliding mechanism includes a movable bracket and a transmission rod that are threaded together. The optical fiber of the humidity measuring module is connected to the movable bracket of the sliding mechanism. The transmission rod is fixedly connected to the top of the nozzle through a fixed frame. One end of the transmission rod is connected to a driving motor. One end of the movable bracket is provided with an internal thread that cooperates with the transmission rod, and the other end is provided with a connection hole that is symmetrical with respect to the nozzle and is plugged in with the optical fiber. The movable bracket can also be plugged in with the transmission rod, and the position of the movable bracket can be directly adjusted manually.

[0014] Preferably, the density measurement module includes a laser transmitter, a laser attenuator, a beam expander, and a collimating lens connected in sequence to one side of the nozzle; a 50% beam splitter, a reflector, and a camera are connected in sequence to the other side of the nozzle, and the 50% beam splitter and the reflector are arranged in pairs. The laser emission direction is perpendicular to the flow direction of hydrogen in the nozzle. The module on the left side of the nozzle can emit a laser beam in a specific direction, and the module on the right side of the nozzle can record the laser imaging after the laser is reflected or refracted, record the change process of the refractive index in the nozzle, and output clear patterns at each moment for analyzing the starting position of condensation.

[0015] Preferably, the humidity measurement module is arranged between the density measurement module and the overflow hole of the nozzle. The optical fiber of the humidity measurement module should avoid interference with the laser optical path of the density measurement module. After the density measurement module detects that the hydrogen is liquefied, the humidity measurement measures the diameter and number of condensed droplets by the extinction method, and then converts the humidity. The optical fiber slides between the density measurement module and the overflow hole of the nozzle, and the position of the optical fiber fixed on the nozzle is changed in turn. Multiple humidity measurements are performed to obtain the hydrogen expansion condition when the liquefaction efficiency is the highest.

[0016] Preferably, the outlet of the second hydrogen compressor is provided with a pressure control valve, which can control the pressure of the hydrogen after secondary compression to ensure that the hydrogen flows out after reaching the target pressure.

[0017] Preferably, the second cooling medium pipeline includes a second heat exchanger and a first heat exchanger, and the hydrogen pipeline also includes a first heat exchanger connected between the first hydrogen compressor and the second heat exchanger. The first heat exchanger is added before the second heat exchanger, and the hydrogen is cooled by heat exchange three times through the first heat exchanger, the second heat exchanger, and the third heat exchanger in sequence, thereby enhancing the cooling effect of the hydrogen.

[0018] Preferably, the circulation unit includes a hydrogen circulation pipeline and valve 3, one end of the hydrogen circulation pipeline is connected to the outlet side of the nozzle, and the other end is connected to the first hydrogen compressor. A part of the precooled hydrogen expands and liquefies in the nozzle to become liquid hydrogen, and the unliquefied hydrogen flows into the hydrogen circulation pipeline through the outlet side of the nozzle, re-enters the precooling unit and the nozzle, and is re-precooled and liquefied.

[0019] Compared with the prior art, the technical solution disclosed in the utility model has the following beneficial effects:

[0020] The nozzle is used to simulate the hydrogen supersonic liquefaction expander, the non-equilibrium condensation and liquefaction phenomenon of hydrogen is simulated, and the humidity in the nozzle is measured by the optical measurement module, so as to realize the test of hydrogen liquefaction phenomenon and the judgment of hydrogen liquefaction efficiency, filling the gap of the prior art in the lack of hydrogen supersonic liquefaction expander experimental equipment for hydrogen liquefaction;

[0021] By adjusting the operating parameters of the hydrogen compressor and heat exchanger, replacing the first cooling medium and the second cooling medium, adjusting the hydrogen temperature and hydrogen pressure, and verifying the relationship between the flow conditions of hydrogen and the hydrogen liquefaction efficiency through simulation analysis, it is possible to guide the structural improvement of the hydrogen supersonic liquefaction expander under different hydrogen flow conditions to increase the liquid hydrogen yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present utility model, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is the working principle diagram of the test equipment of the utility model;

[0024] Figure 2 This is a working principle diagram of the precooling module of the utility model;

[0025] Figure 3 This is a working principle diagram of the liquid hydrogen density measuring unit of the utility model;

[0026] Figure 4 This is a working principle diagram of the liquid hydrogen yield measurement of the utility model;

[0027] Figure 5 It is a structural schematic diagram of the nozzle of the utility model;

[0028] Figure 6 is a schematic diagram of the longitudinal section structure of a nozzle embodiment;

[0029] Figure 7 This is a graph showing the relationship between the liquid hydrogen yield and the longitudinal section of the nozzle when the hydrogen temperature at the nozzle inlet is 41K and 42K.

[0030] Description of Figure Numbers:

[0031] 1 hydrogen supply unit, 2 valve one, 3 precooling unit, 301 first cooling medium compressor, 302 first hydrogen compressor, 303 supersonic liquefaction expander, 304 second hydrogen compressor, 305 first heat exchanger, 306 second heat exchanger, 307 third heat exchanger, 308 temperature and pressure sensor, 4 valve two, 5 nozzle, 501 light-transmitting panel, 6 measuring unit, 601 laser transmitter, 602 laser attenuator, 603 beam expander, 604 collimating lens, 605 50% beam splitter, 606 reflector, 607 camera, 608 fixing frame, 609 transmission rod, 610 movable bracket, 611 optical fiber, 7 valve three, 8 collecting unit. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the core concept of the utility model and the following embodiments, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0033] Example 1, experimental equipment for the homogeneous non-equilibrium condensation and liquefaction of hydrogen, such as Figure 1 , Figure 2 , Figure 5 As shown, it includes a hydrogen supply unit 1, a precooling unit 3 and a nozzle 5 simulating a hydrogen supersonic liquefaction expander connected in sequence, the air inlet side of the nozzle 5 is intermittently connected to the precooling unit 3, the air outlet side of the nozzle 5 is connected to the circulation unit, and the liquid outlet side of the nozzle 5 is connected to the measuring unit 6 and the collecting unit 8. The cross-section of the nozzle 5 is rectangular, and the left and right sides of the nozzle 5 are provided with a light-transmitting panel 501 connected to the measuring unit 6 along the hydrogen flow direction. The precooling unit 3 includes a hydrogen pipeline, a first cooling medium pipeline and a second cooling medium pipeline. The hydrogen pipeline includes a first hydrogen compressor 302, a second heat exchanger 306, a third heat exchanger 307, a second hydrogen compressor 304 and a temperature and pressure sensor 308. The first cooling medium pipeline includes a first cooling medium compressor 301, a second heat exchanger 306 and a supersonic liquefaction expander 303, a third heat exchanger 307, and the second cooling medium pipeline includes a second heat exchanger 306.

[0034] Specifically, the hydrogen supply unit 1 can provide hydrogen, the precooling unit 3 can compress and cool the hydrogen, a valve 2 is provided between the hydrogen supply unit 1 and the precooling unit 3, and the nozzle 5 is used to simulate the hydrogen supersonic liquefaction expander, and the hydrogen reaching the target temperature and target pressure is expanded and liquefied to obtain liquid hydrogen. The air intake method, liquid discharge method and air discharge method of the nozzle 5 are the same as those of the hydrogen supersonic liquefaction expander. A valve 2 4 is provided between the air intake side of the nozzle 5 and the precooling unit 3. The test unit 6 and the collection unit 8 are arranged along the flow direction of the hydrogen, the test unit 6 is connected to both sides of the nozzle 5, and the collection unit 8 is connected to the end of the nozzle 5. The measuring unit 6 can perform a humidity test on the liquid hydrogen in the nozzle 5. The higher the humidity, the higher the hydrogen liquefaction efficiency and the higher the liquid hydrogen yield. The nozzle 5 includes a contraction section and an expansion section, and the expansion section to the outlet is the liquid outlet side. The nozzle 5 is provided with a vortex generator that is the same as the hydrogen supersonic liquefaction expander on the air inlet side. The hydrogen and liquid hydrogen are separated by centrifugal force and collected separately. The liquid hydrogen flows to the end of the liquid outlet side of the nozzle 5 under the action of centrifugal force. The collecting unit 8 collects the liquid hydrogen at the end of the liquid outlet side. The unliquefied hydrogen is led out from the air outlet side of the nozzle 5 and is recovered by the circulation unit and flows back into the precooling unit 3. To facilitate experimental operation, preferably, the hydrogen supply unit 1 is a hydrogen storage tank, precooling is achieved by heat exchange of a cooling medium, the nozzle 5 is made of transparent material, the measuring unit 6 is an optical measuring module, and the collecting unit 8 is a liquid hydrogen storage tank.

[0035] like Figure 5 As shown, the nozzle 5 includes a contraction section and an expansion section. In order to facilitate the display of the contraction and expansion structure, the expansion area at both ends of the nozzle 5 is specially enlarged and displayed. The nozzle 5 should be cylindrical with a smooth and frictionless interior. The upper and lower sides of the nozzle 5 are arc panels that first contract and then expand. The upper and lower arc panels of the nozzle 5 and the left and right light-transmitting panels 501 together form a sealed tube, leaving only the inlet and outlet for hydrogen to flow therein. The shape of the nozzle 5 first contracts and then expands along the flow direction of hydrogen, which facilitates hydrogen to reach a transcritical state, and then a non-equilibrium condensation process occurs. The rectangular cross-section facilitates the connection of the nozzle 5 to the measurement unit 6, and the light-transmitting panel 501 can be applied to a variety of optical measurement modules. The left and right settings of the light-transmitting panel 501 facilitate the connection to the measurement unit 6. Preferably, the light-transmitting panel 501 is made of colorless and transparent tempered glass, and the upper and lower sides of the nozzle 5 can be colorless and transparent tempered glass, or smooth and frictionless metal.

[0036] like Figure 2As shown, the second cooling medium is introduced into the second cooling medium pipeline, the first cooling medium is introduced into the first cooling medium pipeline, the first cooling medium flows through the first cooling medium compressor 301 and the second heat exchanger 306, the second cooling medium cools the first cooling medium in the second heat exchanger 306, the first cooling medium after once cooling continues to flow through the supersonic liquefaction expander 303 for expansion and liquefaction, hydrogen is introduced into the hydrogen pipeline, the hydrogen is compressed by the first hydrogen compressor 302 in sequence, and is cooled by heat exchange with the second cooling medium in the second heat exchanger 306 , heat exchange and cooling with the liquefied first cooling medium in the third heat exchanger 307, and then secondary compression by the second hydrogen compressor 304, and monitoring whether the hydrogen reaches the target temperature and target pressure through the temperature and pressure sensor 308, if the target temperature and target pressure are reached, open the valve 24, so that the hydrogen enters the nozzle 5 through the air intake side, if the target temperature and target pressure are not reached, by adjusting the parameters of the first hydrogen compressor 302 and the second hydrogen compressor 304, replacing the first cooling medium and the second cooling medium, the hydrogen is compressed and cooled to the target temperature and target pressure. Preferably, the first cooling medium and the second cooling medium are both inert gases, the first cooling medium is helium, and the second cooling medium is nitrogen; it can also be that the first cooling medium is nitrogen and the second cooling medium is liquefied natural gas, as long as the liquefaction temperature of the first cooling medium is lower than the liquefaction temperature of the second cooling medium.

[0037] Embodiment 2, based on Embodiment 1, an experimental device for the homogeneous non-equilibrium condensation and liquefaction of hydrogen, the liquid outlet side of the nozzle 5 includes overflow holes evenly spaced along the upper and lower side walls of the nozzle 5, and each overflow hole is connected to the collection unit 8. The liquid outlet side of the nozzle 5 includes the nozzle 5 and the overflow holes located on the upper and lower side walls of the nozzle 5. After the hydrogen flows through the air inlet side, it flows along the nozzle 5. Due to the shape of the nozzle 5 that first contracts and then expands, the volume of the hydrogen is first compressed and then expanded. In this process, the hydrogen is liquefied. Under the action of flow velocity and centrifugal force, the liquid hydrogen flows out along the overflow holes on the upper and lower side walls of the nozzle 5. The overflow holes are arranged at the end of the hydrogen flow direction, and the outlet direction of the overflow holes matches the centrifugal flow direction of the liquid hydrogen. The liquid hydrogen in the nozzle 5 flows to the collection unit 8 through the overflow holes. Preferably, the collection unit 8 is a liquid hydrogen storage tank, and the sizes of the overflow holes are the same. The outlet direction of the overflow holes simulates the liquid outlet side direction of the hydrogen supersonic liquefaction expander.

[0038] Example 3, based on Example 2, an experimental device for the homogeneous non-equilibrium condensation and liquefaction of hydrogen is provided, such as Figure 4As shown, the measuring unit 6 includes a humidity measuring module, which is arranged on a sliding mechanism, and the sliding direction of the sliding mechanism is parallel to the nozzle 5. The humidity measuring module measures the diameter and number of condensed liquid droplets by the extinction method. The humidity measuring module includes an optical fiber 611 and a laser emission box connected by electrical signals, and the optical fiber 611 is slidably connected to the light-transmitting panels 501 on the left and right sides of the nozzle 5 by the sliding mechanism. Humidity measurement measures the diameter and number of condensed liquid droplets by the extinction method, and then converts them to obtain humidity. The hydrogen temperature and hydrogen pressure on the air inlet side of the nozzle 5 are changed in turn. In each test, the optical fiber 611 is fixed at different positions of the nozzle 5 for multiple measurements to obtain the hydrogen expansion conditions when the liquefaction efficiency is the highest.

[0039] Example 4, based on Example 3, an experimental device for the homogeneous non-equilibrium condensation and liquefaction of hydrogen, such as Figure 3 As shown, the measuring unit 6 includes a density measuring module, and the measuring direction of the density measuring module is perpendicular to the light-transmitting panel 501 of the nozzle 5. The density measuring module measures the position, size and growth data of the condensed droplets by shearing interference method. The laser of the density measuring module vertically passes through the light-transmitting panel 501, which is convenient for measuring and recording the hydrogen in the entire nozzle 5. When condensed droplets appear in the hydrogen, the optical signal of the laser passing through the condensed droplets will change.

[0040] Example 5, based on Example 3, an experimental device for the homogeneous non-equilibrium condensation and liquefaction of hydrogen is provided, such as Figure 4 As shown, the sliding mechanism includes a movable bracket 610 slidably connected to the light-transmitting panel 501, and the humidity measurement module is fixedly connected to the movable bracket 610. The sliding mechanism includes a threaded movable bracket 610 and a transmission rod 609, and the optical fiber 611 of the humidity measurement module is connected to the movable bracket 610 of the sliding mechanism. The transmission rod 609 is fixedly connected to the top of the nozzle 5 through a fixed frame 608. One end of the transmission rod 609 is connected to a driving motor. One end of the movable bracket 610 is provided with an internal thread that matches the transmission rod 609, and the other end is provided with a connection hole that is symmetrical with respect to the nozzle 5 and is plugged and matched with the optical fiber 611. The movable bracket 610 can also be plugged with the transmission rod 609, and the position of the movable bracket 610 can be directly adjusted manually.

[0041] Example 6, based on Example 4, an experimental device for the homogeneous non-equilibrium condensation and liquefaction of hydrogen is provided, such as Figure 3As shown, the density measurement module includes a laser emitter 601, a laser attenuator 602, a beam expander 603, and a collimating lens 604 connected in sequence to one side of the nozzle 5; a 50% beam splitter 605, a reflector 606, and a camera 607 are connected in sequence to the other side of the nozzle 5, and the 50% beam splitter 605 and the reflector 606 are arranged in pairs. The module on the left side of the nozzle 5 can emit a laser beam in a specific direction, and the module on the right side of the nozzle 5 can record the laser imaging after the laser is reflected or refracted. The density measurement module records the change process of the refractive index in the nozzle 5 in real time through the shearing interferometer method, obtains the density through conversion, and outputs a clear pattern at each moment for analyzing the starting position of condensation.

[0042] Example 7, based on Example 4, an experimental device for the homogeneous non-equilibrium condensation and liquefaction of hydrogen, wherein the humidity measurement module is arranged between the density measurement module and the overflow hole of the nozzle 5. The optical fiber 611 of the humidity measurement module should avoid interference with the laser optical path of the density measurement module. After the density measurement module detects that the hydrogen is liquefied, the humidity measurement measures the diameter and number of condensed droplets by the extinction method, and then converts the humidity. The optical fiber 611 slides between the density measurement module and the overflow hole of the nozzle 5, and the position of the optical fiber 611 fixed on the nozzle 5 is changed in turn. Multiple humidity measurements are performed to obtain the hydrogen expansion condition when the liquefaction efficiency is the highest.

[0043] Embodiment 8, based on Embodiment 1, in the experimental equipment for hydrogen homogeneous non-equilibrium condensation and liquefaction, a pressure control valve is provided at the outlet of the second hydrogen compressor 304. The pressure control valve can control the pressure of the hydrogen after secondary compression, ensure that the hydrogen flows out after reaching the target pressure, ensure the compression and pre-cooling effect of the hydrogen, and avoid the reduction of liquefaction efficiency due to the failure to reach the hydrogen pressure.

[0044] Example 9, based on Example 1, an experimental device for hydrogen homogeneous non-equilibrium condensation and liquefaction, such as Figure 2 As shown, the second cooling medium pipeline includes a second heat exchanger 306 and a first heat exchanger 305, and the hydrogen pipeline also includes a first heat exchanger 305 connected between the first hydrogen compressor 302 and the second heat exchanger 306. The first heat exchanger 305 is added before the second heat exchanger 306, and the hydrogen is cooled three times by heat exchange through the first heat exchanger 305, the second heat exchanger 306, and the third heat exchanger 307 in sequence. The first heat exchanger 305 and the second heat exchanger 306 are both auxiliary cooling, and the third heat exchanger 307 is the main cooling process. The three coolings enhance the cooling effect of the hydrogen.

[0045] Example 10, based on Example 1, an experimental device for hydrogen homogeneous non-equilibrium condensation and liquefaction, such as Figure 1As shown, the circulation unit includes a hydrogen circulation pipeline and a valve 307, one end of the hydrogen circulation pipeline is connected to the outlet side of the nozzle 5, and the other end is connected to the first hydrogen compressor 302. A part of the precooled hydrogen expands and liquefies in the nozzle 5 to become liquid hydrogen, and the unliquefied hydrogen flows into the hydrogen circulation pipeline through the outlet side of the nozzle 5, re-enters the precooling unit 3 and the nozzle 5, and is re-compressed, precooled and liquefied. Based on the upward flow of hydrogen, the hydrogen circulation pipeline is arranged above the outlet side of the nozzle 5.

[0046] When implementing Example 10, the hydrogen liquefaction efficiency is measured by using experimental equipment and combined with simulation analysis and verification. The experimental and verification methods are as follows:

[0047] Step 1: close the valve 2 4 controlling the connection between the precooling module 3 and the hydrogen liquefaction pipeline, open the valve 2 controlling the switch of the hydrogen supply unit 1, so that hydrogen enters the hydrogen pipeline of the precooling module 3, the second cooling medium is passed into the second cooling medium pipeline, the first cooling medium is passed into the first cooling medium pipeline, and the first cooling medium and the second cooling medium exchange heat in the second heat exchanger 306;

[0048] Step 2: After being cooled, the first cooling medium flows through the supersonic liquefaction expander 303 and the third heat exchanger 307, the second cooling medium assists in precooling the hydrogen in the second heat exchanger 306, and the first cooling medium precools the hydrogen in the third heat exchanger 307, so that the temperature of the hydrogen reaches the target temperature required for expansion and liquefaction;

[0049] Step 3: The low-temperature hydrogen after compression and precooling flows into the second hydrogen compressor 304 for secondary compression, and the temperature and pressure sensor 308 is used to determine whether the temperature and pressure of the hydrogen after secondary compression have reached the required target critical conditions;

[0050] Step 4: Open the second valve 4 to allow the hydrogen reaching the target pressure and target temperature to flow into the nozzle 5, change the hydrogen pressure by adjusting the parameters of the second hydrogen compressor 304, change the hydrogen temperature by replacing the first cooling medium and the second cooling medium, use the single variable method to change the hydrogen temperature and hydrogen pressure in turn, and use the measurement module 6 to measure the liquid hydrogen density and liquid hydrogen yield in turn;

[0051] Step 5: Construct a simulation model based on the hydrogen temperature, hydrogen pressure and nozzle structural parameters set each time, such as Figure 6 to Figure 7 As shown, according to the hydrogen temperature and hydrogen pressure controlled by the experimental equipment, the liquid hydrogen yield of each area in the nozzle 5 is simulated and verified, and the relationship between the hydrogen temperature, hydrogen pressure, nozzle 5 structure and liquid hydrogen yield is obtained to guide the hydrogen supersonic liquefaction expander to improve its liquid hydrogen yield.

[0052] like Figure 6-Figure 7 As shown, Figure 6The simulation model is constructed based on the nozzle 5. The nozzle 5 uses the front section l1 to compress the hydrogen and the rear section l2 to expand the hydrogen. Figure 7 It is a simulation diagram of liquid hydrogen yield. It can be seen that under the condition that nozzle 5 and hydrogen pressure are not changed and only the hydrogen temperature is changed, the liquid hydrogen yield in nozzle 5 changes with the hydrogen flow direction. It can be seen that the liquid hydrogen yield when the hydrogen temperature is 41K is greater than the liquid hydrogen yield when the hydrogen temperature is 42K. The liquid hydrogen yield of nozzle 5 at x=0.06m is the highest. Therefore, the liquid hydrogen yield can be improved by adjusting the hydrogen temperature and hydrogen pressure to guide the hydrogen supersonic liquefaction expander.

[0053] The parts not described in detail in the present invention are all conventional technical means known to those skilled in the art.

[0054] The above content shows and describes the basic principle, main features and beneficial effects of the utility model. The above description is only a preferred embodiment of the utility model and is not intended to limit the utility model. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. Experimental equipment for the homogeneous non-equilibrium condensation and liquefaction of hydrogen, characterized by: The invention comprises a hydrogen supply unit (1), a precooling unit (3) and a nozzle (5) simulating a hydrogen supersonic liquefaction expander connected in sequence, the air inlet side of the nozzle (5) being intermittently connected to the precooling unit (3), the air outlet side of the nozzle (5) being connected to a circulation unit, and the liquid outlet side of the nozzle (5) being connected to a measuring unit (6) and a collecting unit (8), the cross section of the nozzle (5) being rectangular, and light-transmitting panels (501) connected to the measuring unit (6) being arranged on the left and right sides of the nozzle (5) along the hydrogen flow direction, the precooling unit ( 3) comprising a hydrogen pipeline, a first cooling medium pipeline and a second cooling medium pipeline, the hydrogen pipeline comprising a first hydrogen compressor (302), a second heat exchanger (306), a third heat exchanger (307), a second hydrogen compressor (304) and a temperature and pressure sensor (308), the first cooling medium pipeline comprising a first cooling medium compressor (301), a second heat exchanger (306) and a supersonic liquefaction expander (303), a third heat exchanger (307), and the second cooling medium pipeline comprising a second heat exchanger (306).

2. The experimental equipment for homogeneous non-equilibrium condensation and liquefaction of hydrogen according to claim 1, characterized in that: The liquid outlet side of the nozzle (5) comprises overflow holes evenly spaced apart along the upper and lower side walls of the nozzle (5), each overflow hole being connected to a collection unit (8).

3. The experimental equipment for homogeneous non-equilibrium condensation and liquefaction of hydrogen according to claim 2, characterized in that: The measuring unit (6) comprises a humidity measuring module, which is arranged on a sliding mechanism, and the sliding direction of the sliding mechanism is parallel to the nozzle (5).

4. The experimental equipment for homogeneous non-equilibrium condensation and liquefaction of hydrogen according to claim 3, characterized in that: The measuring unit (6) comprises a density measuring module, wherein a measuring direction of the density measuring module is perpendicular to the light-transmitting panel (501) of the nozzle (5).

5. The experimental equipment for homogeneous non-equilibrium condensation and liquefaction of hydrogen according to claim 3, characterized in that: The sliding mechanism comprises a movable bracket (610) slidably connected to the light-transmitting panel (501), and the humidity measurement module is fixedly connected to the movable bracket (610).

6. The experimental equipment for homogeneous non-equilibrium condensation and liquefaction of hydrogen according to claim 4, characterized in that: The density measurement module comprises a laser emitter (601), a laser attenuator (602), a beam expander (603), and a collimating lens (604) which are sequentially connected to one side of the nozzle (5); a 50% beam splitter (605), a reflector (606), and a camera (607) are sequentially connected to the other side of the nozzle (5), and the 50% beam splitter (605) and the reflector (606) are arranged in pairs.

7. The experimental equipment for homogeneous non-equilibrium condensation and liquefaction of hydrogen according to claim 4, characterized in that: The humidity measuring module is arranged between the density measuring module and the overflow hole of the nozzle (5).

8. The experimental equipment for homogeneous non-equilibrium condensation and liquefaction of hydrogen according to claim 1, characterized in that: The outlet of the second hydrogen compressor (304) is provided with a pressure control valve.

9. The experimental equipment for homogeneous non-equilibrium condensation and liquefaction of hydrogen according to claim 1, characterized in that: The second cooling medium pipeline includes a second heat exchanger (306) and a first heat exchanger (305), and the hydrogen pipeline also includes a first heat exchanger (305) connected between the first hydrogen compressor (302) and the second heat exchanger (306).

10. The experimental equipment for hydrogen homogeneous non-equilibrium condensation and liquefaction according to claim 1, characterized in that: The circulation unit comprises a hydrogen circulation pipeline and a valve three (7), one end of the hydrogen circulation pipeline is connected to the gas outlet side of the nozzle (5), and the other end is connected to the first hydrogen compressor (302).

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