Device for gas-liquid separation

Abstract

The utility model relates to a device for gas-liquid separation belongs to hydrogen fuel cell engine hydrogen supply circulation system's gas-liquid separation technical field, aiming at the problem that separation efficiency and system resistance are difficult to balance in prior art, cannot give consideration to different particle size droplet separation and impurity gas discharge, the device includes upper casing and lower casing, the upper casing is divided into rough filter cavity and fine filter cavity through vertical partition, is equipped with radial guide component and I -shaped impact separation component in rough filter cavity, is equipped with cyclone separator with inner cylinder in fine filter cavity, and lower casing forms water collecting cavity, gas-liquid mixture is guided to impact separation component and separates big droplet after being guided to guide component, enters cyclone separator and separates small droplet through centrifugal force, and separated liquid converges into water collecting cavity, and the outlet cavity passes through hydrogen concentration sensor control impurity gas discharge, the utility model realizes different particle size droplet high -efficient separation, reduces system resistance, guarantees that hydrogen purity meets the requirement, promotes hydrogen recycling rate, is applicable to hydrogen fuel cell engine hydrogen supply circulation system.

Description

Technical Field

[0001] This utility model relates to the field of gas-liquid separation technology in the hydrogen supply circulation system of a hydrogen fuel cell engine. Background Technology

[0002] Hydrogen fuel cells are power generation devices that directly convert chemical energy into electrical energy by reacting hydrogen fuel with oxygen in the air. They have advantages such as high energy density, high conversion efficiency, and zero pollution emissions, and therefore have broad application prospects in aerospace, military power supply, transportation, stationary power stations, and portable power supplies.

[0003] In the hydrogen supply cycle system of a hydrogen fuel cell engine, in order to improve the reaction efficiency of the stack, an excess coefficient needs to be set when hydrogen enters the stack to participate in the electrochemical reaction, which causes some unreacted hydrogen to be discharged with the reaction products (such as liquid water, water vapor, etc.).

[0004] If unreacted hydrogen is directly released into the atmosphere, it will not only waste hydrogen but may also cause environmental pollution. Therefore, it is necessary to use a hydrogen supply and circulation system to return the unreacted hydrogen to the anode inlet of the fuel cell stack to achieve efficient recycling of hydrogen.

[0005] In this process, the gas-liquid separation device is a key component. Its function is to separate liquid water in the circulating gas flow to prevent liquid water from entering the fuel cell stack or circulating pump (ejector), which would lead to a decrease in system efficiency or equipment damage.

[0006] However, current hydrogen-water separation devices in the industry have the following significant shortcomings in practical applications:

[0007] First, the separation efficiency is low, which cannot meet the high-efficiency separation requirements of humidifier-free systems.

[0008] Existing gas-liquid separation devices mostly rely on a single separation principle (such as inertial sedimentation or centrifugal separation). For example, inertial separation is achieved by simply using baffle impact, or centrifugal separation is achieved by using a single hydrocyclone.

[0009] A single separation principle is insufficient to meet the separation requirements of droplets of different sizes: inertial separation is effective for large droplets (such as those above 50 μm), but it is not effective for capturing small droplets (such as those below 50 μm); centrifugal separation can separate small droplets, but it is easy for large droplets to be entrained due to excessive flow rate.

[0010] Secondly, the high resistance during operation places high demands on the power consumption of the downstream circulating pump (ejector).

[0011] To improve separation efficiency, existing devices often enhance the separation effect by narrowing the flow channel and increasing the number of impacts, but these designs lead to increased airflow pressure drop and increased system resistance.

[0012] The industry has long prioritized "separation efficiency" as the primary optimization goal, while neglecting the synergistic balance between "separation efficiency and resistance." Technical approaches have been limited to local structural optimization (such as increasing filter density and reducing hydrocyclone diameter), without reducing resistance from the perspective of overall flow field design. This results in the circulating pump consuming more energy to overcome resistance, increasing the overall power consumption of the system.

[0013] Third, it lacks an exhaust port for impurity gases, making it unable to effectively remove impurity gases.

[0014] Existing device designs focus on the gas-liquid separation function itself, without considering the accumulation of system-level impurity gases (such as nitrogen, unreacted air, etc.). Impurity gases need to be connected to the exhaust device through external pipelines, which increases the complexity of the system.

[0015] The shortcomings of the aforementioned existing technologies directly restrict the performance of the hydrogen supply cycle system of hydrogen fuel cell engines:

[0016] Insufficient separation efficiency leads to excessively high liquid water content in the circulating hydrogen, affecting the stack reaction efficiency;

[0017] Excessive resistance increases system energy consumption and reduces engine economy;

[0018] The accumulation of impurity gases affects gas purity and system safety, ultimately making it difficult to improve hydrogen utilization.

[0019] Therefore, developing a gas-liquid separation device that can efficiently separate gas-liquid mixtures, reduce system resistance, and integrate exhaust and pressure detection functions is of great significance for promoting the technological advancement of hydrogen fuel cell engines. Utility Model Content

[0020] The purpose of this invention is to provide a technical solution that can achieve efficient and coordinated separation of droplets of different sizes in a gas-liquid mixture. Through specific structural design, the separation efficiency is improved, overcoming the shortcomings of low separation efficiency and high system resistance in the prior art.

[0021] To achieve the above objectives, the gas-liquid separation device of this invention is used in the hydrogen supply circulation system of a hydrogen fuel cell engine. It includes an upper housing, to which a lower housing is sealed downwards. The lower housing is wider at the top and narrower at the bottom, and its side walls are inclined. A water collection chamber is formed inside the lower housing, and a water outlet is provided at the bottom end of the lower housing.

[0022] The upper shell has a vertically arranged longitudinal partition in the middle, and the longitudinal partition is connected downward to a transverse partition for water permeability and air blocking. The transverse partition closes the top of the lower shell on one side of the longitudinal partition, and the transverse partition has a drain hole that is permeable from top to bottom.

[0023] Above the transverse diaphragm, along the direction of airflow from upstream to downstream, there is a flow guiding component and an impact separation component. The upper housing adjacent to the flow guiding component is connected to an air inlet. The impact separation component is located between the flow guiding component and the longitudinal diaphragm.

[0024] The longitudinal partition plate and the upper shell together form a fine filtration chamber on the other side of the air inlet, and a cyclone separator is provided in the fine filtration chamber; an air outlet chamber is provided between the cyclone separator and the top of the upper shell, and the air outlet end of the cyclone separator is connected to the air outlet chamber; an air outlet that is connected to the air outlet chamber is connected to the top wall of the upper shell in the middle of the air outlet chamber.

[0025] The longitudinal diaphragm above the transverse diaphragm is connected to the inclined diaphragm. The inclined diaphragm, together with the longitudinal diaphragm above it and the upper shell, forms a coarse filtration chamber. The flow guiding assembly and the impact separation assembly are located in the coarse filtration chamber. The inclined diaphragm, together with the longitudinal diaphragm below it, the upper shell, and the transverse diaphragm, forms a water collection chamber. The longitudinal diaphragm is provided with a communication port that connects the inlet of the cyclone separator to the coarse filtration chamber.

[0026] Taking the upstream and downstream direction of the airflow as a reference, the connection between the inclined baffle and the longitudinal baffle is the downstream end of the inclined baffle. The downstream end of the inclined baffle is lower than its upstream end. The downstream end of the inclined baffle is provided with water permeable holes that allow water to pass through from top to bottom. The inclined structure of the inclined baffle is used for the water that gathers on it to flow to the water permeable holes and enter the water collection chamber downwards. The water in the water collection chamber falls into the water collection chamber through the water drop holes.

[0027] The air guide components are set one-to-one with the air inlets. The air guide components include several vertically arranged air guide plates. On the horizontal cross section, each air guide plate is evenly distributed in an arc shape with the intersection of the air inlet and the upper shell as the center, thus forming a radially evenly spaced structure.

[0028] The impact separation assembly includes several impact separation units arranged at intervals. The horizontal cross-section of each impact separation unit is I-shaped, and the adjacent impact separation units form an impact separation channel with multiple bends. The upstream inlet of each impact separation channel is inclined towards the flow direction of the guide assembly. The downstream outlet of each impact separation channel is towards the longitudinal partition plate.

[0029] Two cyclone separators are arranged side by side with a gap between them. The top of each cyclone separator is connected to the same partition plate. The circumferential edge of the partition plate is connected to the upper shell and the longitudinal partition plate. The partition plate, the upper shell and the longitudinal partition plate above it form the air outlet chamber.

[0030] The upper part of the hydrocyclone separator is a cylindrical section, which is integrally connected to a conical section that is larger at the top and smaller at the bottom. The bottom end of the conical section is provided with a drain outlet that extends downward into the water collection chamber inside the lower shell.

[0031] Each of the connecting ports corresponds to a hydrocyclone separator; each connecting port is connected to a tangential channel, and each tangential channel is connected to the cylindrical section of the corresponding hydrocyclone separator along the tangential direction.

[0032] The cylindrical section of the cyclone separator has an inner cylinder coaxially arranged inside. The upper end of the inner cylinder is connected to the opening on the partition plate and serves as the outlet of the cyclone separator. The lower end of the inner cylinder is used for the airflow to enter the inner cylinder from bottom to top through the rotating flow and then flow to the outlet chamber. The inner cylinder is used to extend the path of the tangential airflow in the cyclone separator, thereby improving the efficiency of gas-liquid cyclone separation.

[0033] The ratio of the diameter of the inner cylinder to the diameter of the cylindrical section of the cyclone separator is 1:2 to 1:4, so that the gas outlet velocity matches the cyclone intensity inside the cyclone separator.

[0034] The outlet is connected to the downstream circulation pump or ejector inlet flange via an external outlet pipeline, and an outlet solenoid valve is installed on the outlet pipeline; a hydrogen concentration sensor is installed in the middle of the outlet chamber in the height direction; the pressure in the outlet chamber is higher than atmospheric pressure.

[0035] The upper housing is also equipped with a miscellaneous gas outlet connected to the exhaust chamber. The miscellaneous gas outlet is used to install the exhaust solenoid valve, which is open to the atmosphere. The hydrogen concentration sensor, exhaust solenoid valve, and exhaust solenoid valve are all connected to the vehicle ECU via wiring. The vehicle ECU has a built-in lower limit of hydrogen concentration threshold MIN, where MIN = 99.97%. When the detection value of the hydrogen concentration sensor is less than MIN, the vehicle ECU opens the exhaust solenoid valve and closes the exhaust solenoid valve at the same time, using the pressure difference between the exhaust chamber and atmospheric pressure to discharge the impurity gas. When the detection value of the hydrogen concentration sensor is greater than or equal to MIN, the vehicle ECU closes the exhaust solenoid valve and opens the exhaust solenoid valve at the same time, allowing hydrogen to be output normally for use by the fuel cell system.

[0036] Two air inlets are arranged side by side at intervals. Both air inlets are used to introduce unreacted hydrogen gas discharged from the anode outlet of the fuel cell stack. The two air inlets are used to reduce the hydrogen gas flow rate to keep the inertial impaction within the optimal Reynolds number range.

[0037] The taper of the cone section of the cyclone separator is 1:3 to 1:5.

[0038] A drain solenoid valve is installed at the water outlet, and a water level sensor is installed in the water collection chamber. Both the water level sensor and the drain solenoid valve are connected to the vehicle ECU via wiring.

[0039] This utility model has the following advantages:

[0040] This invention utilizes a two-stage cascade structure of "impact separation + vortex separation" to first separate large droplets using inertia and gravity sedimentation, and then separate small droplets using centrifugal force, thereby achieving efficient separation of droplets of different sizes and improving separation efficiency. The sealed connection between the upper and lower shells ensures that gas and liquid do not leak out, and the water collection chamber collects the separated liquid uniformly, improving the system integration.

[0041] The inclined baffle separates the airflow in the coarse filter chamber from the horizontal baffle. Water can only enter the collection chamber through the perforations at the downstream end (lowest point) of the inclined baffle. The inclined baffle acts as a "threshold," allowing water to pass through only small holes, while the rest of the area is completely sealed off by the horizontal baffle, achieving "air-to-liquid flow" in the vertical direction. This prevents the high-speed airflow from creating a suction effect above the horizontal baffle, which would otherwise draw the separated water back into the airflow, thus avoiding a reduction in air-water separation efficiency. The inclined design of the baffle promotes liquid flow along the baffle surface to the perforations, improving liquid discharge efficiency.

[0042] In summary, the inclined baffle can isolate the gas path and liquid path through the height difference, implement the design logic of "collect first and then slowly discharge", avoid the separated water being drawn back into the airflow, and improve the separation efficiency.

[0043] Each deflector is arranged radially and evenly with the air inlet as the center, which can evenly disperse the incoming airflow downstream, thus providing good airflow distribution and stabilization.

[0044] The impact separation channel has multiple bends, which allows water-containing hydrogen gas to collide with the impact separation unit more frequently as it flows through the channel, thus improving the efficiency of gas-liquid impact separation.

[0045] After the gas-liquid mixture impacts the I-shaped impact separation unit, the large droplets adhere to the surface of the impact separation unit due to inertia. Under the action of gravity, they flow along the inclined transverse baffle, enter the water collection chamber through the water permeable holes, and finally fall into the water collection chamber through the water drop holes, thus achieving continuous separation of "drainage-impact-convergence".

[0046] The upstream inlet of each impact separation channel is inclined toward the direction of the flow guide component, so that most of the airflow is pre-impacted on the side wall of the impact separation unit before entering the impact separation channel, and only enters the impact separation channel after the impact occurs, which further improves the efficiency of gas-liquid (hydrogen and water) impact separation.

[0047] The bottom end of the conical section extends into the water collection chamber, allowing the water separated by the hydrocyclone separator to flow directly into the collection chamber. This compact structure prevents water separated during the fine filtration stage from flowing into the upper casing outside the hydrocyclone separator. The inner cylinder design prevents gas entering through the tangential channel from quickly entering the outlet chamber upwards through the opening on the partition plate, effectively extending the path of the incoming gas as it rotates within the hydrocyclone separator, thereby improving the efficiency of gas-liquid hydrocyclone separation.

[0048] Without an inner cylinder, the gas would have to be discharged entirely from the top of the upper cylindrical section of the cyclone separator, which would easily create an upward airflow along the inner wall, re-entraining the separated liquid (secondary entrainment). The inner cylinder, through "central flow guidance," physically isolates the gas and liquid flow paths, fundamentally eliminating the disturbance of the airflow to the liquid and further improving the efficiency of gas-liquid cyclone separation.

[0049] In cyclone separation, the gas velocity varies with axial position (high velocity at the inlet, gradually decreasing downwards), easily generating local vortices due to uneven velocity distribution. Matching the diameter of the inner cylinder to the diameter of the cylindrical section of the cyclone separator (diameter ratio 1:2~1:4) allows for tailoring the gas outlet velocity to the cyclone intensity by adjusting the cross-sectional area of ​​the central channel, thus ensuring rapid gas discharge to reduce disturbance while avoiding disruption of the cyclone field required for centrifugal separation due to excessively high outlet velocity. This balance reduces flow field fluctuations and further decreases the probability of liquid being secondary entrained by the gas flow.

[0050] This invention relates to a hydrogen-water separation device, which returns unreacted hydrogen to the anode inlet of the fuel cell stack in hydrogen-powered vehicles, achieving efficient recycling of hydrogen. Hydrogen may contain small amounts of impurities such as air. Existing technologies lack an outlet for these impurities, causing them to enter the anode inlet of the fuel cell stack along with the hydrogen, negatively impacting the hydrogen fuel cell.

[0051] These impurities are significantly denser than hydrogen (the least dense gas). In the exhaust chamber, hydrogen preferentially flows upwards through the outlet, while impurities gradually accumulate, resulting in a phenomenon where hydrogen accumulates in the upper middle section and impurities gradually accumulate in the lower middle section during long-term use. This invention places the hydrogen concentration sensor in the middle of the exhaust chamber's height. When the detected hydrogen concentration is below a preset threshold, the vehicle ECU activates the exhaust system to expel impurities from the chamber, ensuring that the hydrogen discharged through the outlet meets the purity requirements of the hydrogen fuel cell stack and preventing performance degradation or damage due to impurities.

[0052] Given the current state of hydrogen fuel cell stacks, introducing unreacted hydrogen through a single inlet can lead to excessively high flow rates and reduced impact separation efficiency. By installing two inlets side-by-side at intervals, the flow rate can be reduced, preventing excessive flow rates from lowering impact separation efficiency.

[0053] The specific principle is: impact separation relies on the "velocity difference → inertia difference" to throw the droplets onto the wall. When the flow velocity is too high, the drag force of the airflow on the droplets increases, and the droplets "follow" the airflow more closely. The centrifugal / inertial distance required to deviate from the streamline becomes shorter, and the probability of impact decreases.

[0054] Excessive velocity creates localized turbulence before impacting the separation unit, causing droplets to be re-entrained and broken up, and even the already attached liquid film is torn apart and re-introduced into the mainstream. At excessively high velocities, the stagnation time (the point in the flow field where the local velocity is zero) is shortened, and droplets do not have enough time to "fail to change direction" before bypassing the impact separation unit, naturally reducing separation efficiency. Specifically, the faster the airflow velocity, the more the high-pressure zone at the stagnation point is compressed spatially, reducing the time (Δt) required for droplets to pass through this zone. Inertial separation requires sufficient Δt for droplets to complete the process of "shifting towards the wall → attaching"; a shorter Δt means droplets leave with the airflow before fully adhering to the wall, leading to a decrease in capture rate.

[0055] Therefore, splitting the same flow rate into two inlets halves the speed of a single pipe, which helps to keep the inertial impaction within the optimal Reynolds number range and maintain efficiency.

[0056] The centrifugal force generated by the swirling flow is positively correlated with the airflow velocity. By optimizing the taper and diameter ratio of the conical tube, the separation efficiency and resistance can be balanced.

[0057] During use, once the water level in the water collection chamber reaches the threshold preset in the vehicle ECU, the vehicle ECU opens the drain solenoid valve to drain the accumulated water, ensuring timely drainage while utilizing the volume of the water collection chamber to avoid frequent drainage operations. Attached Figure Description

[0058] Figure 1 This is a three-dimensional structural schematic diagram of the device for gas-liquid separation according to this utility model, viewed from an obliquely upward angle.

[0059] Figure 2 This is a three-dimensional structural schematic diagram of the gas-liquid separation device of this utility model from another angle, with the viewpoint being diagonally downward.

[0060] Figure 3 This is a three-dimensional structural diagram of the present invention after the upper shell has been removed, with the viewpoint from the coarse filter side.

[0061] Figure 4 This is a three-dimensional structural diagram of the present invention from another angle after the upper shell is removed, with the viewing angle being from the fine filter side.

[0062] Figure 5 This is a schematic diagram of the main structure of this utility model.

[0063] Figure 6 yes Figure 5 AA sectional view.

[0064] Figure 7 yes Figure 5 BB cross-sectional view.

[0065] Figure 8 yes Figure 5 EE sectional view.

[0066] Figure 9 yes Figure 5 GG cross-sectional view.

[0067] Figure 10 This is a schematic diagram of the main structure of this utility model after removing the upper shell.

[0068] Figure 11 yes Figure 5 FF sectional view. Detailed Implementation

[0069] like Figures 1 to 11 As shown, this utility model provides a device for gas-liquid separation for hydrogen supply circulation system of hydrogen fuel cell engine, including upper shell 1, upper shell 1 is sealed to lower shell 2 through flange structure 3, lower shell 2 is shaped like a truncated pyramid with larger upper part and smaller lower part and its side wall is inclined surface; the inner cavity of lower shell 2 forms water collection cavity 4, and the bottom end of lower shell 2 is provided with water outlet 5.

[0070] The upper shell 1 has a vertically arranged longitudinal partition 6 in the middle. The longitudinal partition 6 is connected downward to a transverse partition 7 for water permeability and air blocking. The transverse partition 7 closes the top of the lower shell 2 on one side of the longitudinal partition 6. The transverse partition 7 has a number of vertically permeable drainage holes 8 evenly spaced on it.

[0071] Above the transverse partition 7, a flow guiding component and an impact separation component are provided along the direction of airflow from upstream to downstream. The upper housing 1 adjacent to the flow guiding component is connected to an air inlet 9. The impact separation component is located between the flow guiding component and the longitudinal partition 6.

[0072] The longitudinal partition 6, on the other side of the air inlet 9, and the upper housing 1 form a fine filtration chamber 10, which contains a cyclone separator. An air outlet chamber 11 is provided between the cyclone separator and the top of the upper housing 1, with the air outlet end of the cyclone separator communicating with the air outlet chamber 11. An air outlet 12, communicating with the air outlet chamber 11, is connected to the top wall of the upper housing 1 in the middle of the air outlet chamber 11. The water collection chamber 4 has a volume greater than or equal to 200 ml to ensure sufficient water capacity.

[0073] This invention utilizes a two-stage cascade structure of "impact separation + vortex separation" to first separate large droplets using inertia and gravity sedimentation, and then separate small droplets using centrifugal force, thereby achieving efficient separation of droplets of different sizes and improving separation efficiency. The sealed connection between the upper shell 1 and the lower shell 2 ensures that gas and liquid do not leak out, and the water collection chamber 4 collects the separated liquid uniformly, improving the system integration.

[0074] A longitudinal partition 6 above the transverse partition 7 is connected to an inclined partition 13. The inclined partition 13, the longitudinal partition 6 above it, and the upper housing 1 on one side of the air inlet 9 form a coarse filter chamber 14. The flow guiding assembly and the impact separation assembly are located in the coarse filter chamber 14. The inclined partition 13, the longitudinal partition 6 below it, the upper housing 1, and the transverse partition 7 form a water collection chamber 15. The longitudinal partition 6 is provided with a communication port 16 that connects the inlet of the cyclone separator to the coarse filter chamber 14.

[0075] Taking the upstream and downstream direction of the airflow as a reference, the connection between the inclined baffle 13 and the longitudinal baffle 6 is the downstream end of the inclined baffle 13. The downstream end of the inclined baffle 13 is lower than its upstream end. The downstream end of the inclined baffle 13 is provided with a water-permeable hole 17 that is open from top to bottom. The inclined structure of the inclined baffle 13 is used for the water that gathers on it to flow to the water-permeable hole 17 and enter the water collection chamber 15 downwards. The water in the water collection chamber 15 falls into the water collection chamber 4 through the water drop hole 8.

[0076] The inclined baffle 13 has an angle of 5° or greater and 10° or less with respect to the horizontal plane. This ensures efficient liquid flow while preventing liquid residue or secondary entrainment, thus improving the stability and efficiency of gas-liquid separation. Specifically, it promotes rapid liquid flow and eliminates liquid residue: the inclined angle allows the separated liquid to flow downwards along the plate surface under gravity, preventing slow liquid flow and residue on the baffle surface due to an angle that is too small (e.g., <5°) (especially since low-viscosity liquid water is prone to retention due to surface tension). This ensures that the liquid flows downwards into the water collection chamber 15 through the water permeable hole 17 at the connection between the longitudinal baffle 6 and the inclined baffle 13. Limiting the angle to ≤10° also prevents excessively fast liquid flow due to an angle that is too large (e.g., >10°), which could cause splashing when impacting the lower shell 2 or small holes, and re-entraining by the airflow (secondary entrainment), ensuring stable liquid separation.

[0077] The inclined baffle 13 separates the airflow in the coarse filter chamber 14 from the transverse baffle 7. Water can only enter the water collection chamber 15 through the water permeable hole 17 at the downstream end (lowest point) of the inclined baffle 13. The inclined baffle 13 acts as a "threshold," allowing water to pass through only small holes, while the rest of the area is completely sealed off by the transverse baffle 7, achieving "air-liquid separation" in the vertical direction. This prevents the high-speed airflow from creating a suction effect above the transverse baffle 7, which would otherwise draw the separated water back into the airflow, thus avoiding a reduction in the efficiency of air-water separation. The inclined design of the inclined baffle 13 promotes the convergence of liquid along the plate surface towards the water permeable hole 17, improving the liquid discharge efficiency.

[0078] In summary, the inclined baffle 13 can achieve the separation of the gas path and the liquid path through the height difference, implement the design logic of "collect first and then slowly discharge", avoid the separated water being drawn back into the airflow, and improve the separation efficiency.

[0079] The flow guiding components are set one-to-one with the air inlet 9. The flow guiding components include several vertically arranged flow guiding plates 18. On the horizontal cross section, each flow guiding plate 18 is evenly distributed in an arc shape with the intersection of the air inlet 9 and the upper shell 1 as the center, thus forming a radially evenly spaced structure.

[0080] The impact separation assembly includes several impact separation units 19 arranged at intervals. The horizontal cross-section of each impact separation unit 19 is I-shaped. The adjacent impact separation units 19 form an impact separation channel 20 with multiple bends. The upstream inlet of each impact separation channel 20 is inclined towards the flow direction of the flow guide assembly. The downstream outlet of each impact separation channel 20 is towards the longitudinal partition plate 6.

[0081] Each guide vane 18 is arranged radially and evenly with the air inlet 9 as the center, which can evenly disperse the incoming airflow downstream, and has the effect of uniformly distributing and stabilizing the airflow.

[0082] The impact separation channel 20 has multiple bends, which allows water-containing hydrogen gas to collide with the impact separation unit 19 more times when it flows through the impact separation channel 20, thereby improving the efficiency of gas-liquid impact separation.

[0083] After the gas-liquid mixture impacts the I-shaped impact separation unit 19, the large droplets adhere to the surface of the impact separation unit 19 due to inertia. Under the action of gravity, they flow along the inclined transverse partition 13, enter the water collection chamber 15 through the water permeable hole 17, and finally fall into the water collection chamber 4 through the water drop hole 8, realizing the continuous separation of "drainage-impact-convergence".

[0084] The upstream inlet of each impact separation channel 20 is inclined toward the flow direction of the flow guide component, so that most of the airflow is pre-impacted on the side wall of the impact separation unit 19 before entering the impact separation channel 20, and only enters the impact separation channel 20 after the impact occurs, which further improves the efficiency of gas-liquid (hydrogen and water) impact separation.

[0085] Two cyclone separators are arranged side by side with a gap between them. The top of the two cyclone separators are connected to the same partition plate 21. The circumferential edge of the partition plate 21 is connected to the upper shell 1 and the longitudinal partition plate 6. The partition plate 21, the upper shell 1 and the longitudinal partition plate 6 above it form the air outlet chamber 11.

[0086] The upper part of the hydrocyclone separator is a cylindrical section 22, and the cylindrical section 22 is integrally connected to a conical section 23 that is larger at the top and smaller at the bottom. The bottom end of the conical section 23 is provided with a drain outlet 24 and extends downward into the water collection chamber 4 inside the lower shell 2.

[0087] Each of the connecting ports 16 corresponds to a hydrocyclone separator; each connecting port 16 is connected to a tangential channel 25, and each tangential channel 25 is connected to the cylindrical section 22 of the corresponding hydrocyclone separator along the tangential direction.

[0088] An inner cylinder 26 is coaxially arranged inside the cylindrical section 22 of the cyclone separator. The upper end of the inner cylinder 26 communicates with the opening on the partition plate 21 and serves as the outlet end of the cyclone separator. The lower end of the inner cylinder 26 is used for the rotating airflow to enter the inner cylinder 26 from bottom to top and then flow to the outlet chamber 11. The inner cylinder 26 is used to extend the path of the tangential airflow rotating in the cyclone separator, thereby improving the efficiency of gas-liquid cyclone separation and making the airflow more stable.

[0089] The bottom end of the conical section 23 extends into the water collection chamber 4, allowing the water separated by the hydrocyclone separator to flow directly into the water collection chamber 4. This compact structure prevents water separated during the fine filtration stage from flowing into the upper housing 1 outside the hydrocyclone separator. The inner cylinder 26 prevents the gas entering through the tangential channel 25 from quickly entering the outlet chamber 11 through the opening on the partition plate 21, effectively extending the path of the incoming gas as it rotates within the hydrocyclone separator, thereby improving the efficiency of gas-liquid hydrocyclone separation.

[0090] Without the inner cylinder 26, the gas would need to be discharged entirely from the top of the upper cylindrical section 22 of the cyclone separator, which would easily form an upward airflow along the inner wall, re-entraining the separated liquid (secondary entrainment). The inner cylinder 26, through "central flow guidance," physically isolates the gas and liquid flow paths, fundamentally eliminating the disturbance of the airflow to the liquid and further improving the efficiency of gas-liquid cyclone separation.

[0091] The diameter ratio of the inner cylinder 26 to the diameter of the cylindrical section 22 of the cyclone separator is 1:2 to 1:4, so that the gas outlet velocity matches the cyclone intensity inside the cyclone separator.

[0092] In cyclone separation, the gas velocity varies with axial position (high velocity at the inlet, gradually decreasing downwards), easily generating local vortices due to uneven velocity distribution. Matching the diameter of the inner cylinder 26 to the diameter of the cylindrical section 22 of the cyclone separator (diameter ratio 1:2~1:4) allows for adjustments to the cross-sectional area of ​​the central channel to match the gas discharge velocity with the cyclone intensity, tailored to the specific characteristics of a hydrogen fuel cell. This ensures rapid gas discharge to reduce disturbance while preventing excessively high discharge velocity from disrupting the cyclone field required for centrifugal separation. This balance reduces flow field fluctuations, further decreasing the probability of liquid being secondary entrained by the gas flow.

[0093] The outlet 12 is connected to the downstream circulation pump or ejector inlet flange via an external outlet pipeline, and an outlet solenoid valve is provided on the outlet pipeline; a hydrogen concentration sensor is provided in the middle of the outlet chamber 11 in the height direction; the pressure in the outlet chamber 11 is higher than atmospheric pressure; the outlet solenoid valve and the hydrogen concentration sensor are conventional parts and are not shown in the figure.

[0094] The upper housing 1 is also equipped with a miscellaneous gas outlet 27 connected to the gas outlet chamber 11. The miscellaneous gas outlet 27 is used to install the exhaust solenoid valve, which is open to the atmosphere. The hydrogen concentration sensor, exhaust solenoid valve, and gas outlet solenoid valve are all connected to the vehicle ECU via wiring. The vehicle ECU has a built-in lower limit hydrogen concentration threshold MIN, where MIN = 99.97% (volume ratio). When the detection value of the hydrogen concentration sensor is less than MIN, the vehicle ECU opens the exhaust solenoid valve and closes the gas outlet solenoid valve simultaneously, using the pressure difference between the gas outlet chamber 11 and atmospheric pressure to expel the impurity gas. When the detection value of the hydrogen concentration sensor is greater than or equal to MIN, the vehicle ECU closes the exhaust solenoid valve and opens the gas outlet solenoid valve simultaneously, allowing hydrogen to be output normally for use by the fuel cell system. The exhaust solenoid valve, gas outlet solenoid valve, and hydrogen concentration sensor are all conventional parts and are not shown in the figure.

[0095] This invention relates to a hydrogen-water separation device, which returns unreacted hydrogen to the anode inlet of the fuel cell stack in hydrogen-powered vehicles, achieving efficient recycling of hydrogen. Hydrogen may contain small amounts of impurities such as air. Existing technologies lack an impurity outlet 27, causing these impurities to enter the anode inlet of the fuel cell stack along with the hydrogen, negatively impacting the hydrogen fuel cell.

[0096] These impurities are significantly heavier than hydrogen (the least dense gas). In the outlet chamber 11, hydrogen preferentially flows upward through the outlet 12 downstream, while impurities gradually accumulate in the outlet chamber 11. This results in a phenomenon where hydrogen accumulates in the upper middle part and impurities gradually accumulate in the lower middle part during long-term use. This invention places the hydrogen concentration sensor in the middle of the outlet chamber 11 in the height direction. When the detected hydrogen concentration is below a preset threshold, the vehicle ECU activates the exhaust device to expel the impurities from the chamber, ensuring that the purity of the hydrogen discharged through the outlet 12 meets the requirements for use in the hydrogen fuel cell stack and preventing performance degradation or damage to the stack due to the entry of impurities.

[0097] Two air inlets 9 are arranged side by side at intervals. Both air inlets 9 are used to introduce unreacted hydrogen gas discharged from the anode outlet of the fuel cell stack. The two air inlets 9 are used to reduce the hydrogen gas flow rate to keep the inertial impaction within the optimal Reynolds number range.

[0098] Given the current state of hydrogen fuel cell stacks, introducing unreacted hydrogen through a single inlet 9 may result in excessively high flow rates, reducing impact separation efficiency. By placing two inlets 9 side-by-side at intervals, the flow rate can be reduced, preventing excessive flow rates from lowering impact separation efficiency.

[0099] The specific principle is: impact separation relies on the "velocity difference → inertia difference" to throw the droplets onto the wall. When the flow velocity is too high, the drag force of the airflow on the droplets increases, and the droplets "follow" the airflow more closely. The centrifugal / inertial distance required to deviate from the streamline becomes shorter, and the probability of impact decreases.

[0100] Excessive velocity creates local turbulence before impact separation unit 19, causing droplets to be re-entrained and broken up, and the already attached liquid film is also torn apart and carried back into the mainstream. When the velocity is too high, the stagnation time (the point in the flow field where the local velocity is zero) is shortened, and the droplets do not have time to "fail to turn" before bypassing impact separation unit 19, naturally reducing the separation efficiency. Specifically, the faster the airflow velocity, the more the high-pressure zone at the stagnation point is compressed in space, and the time (Δt) required for the droplet to pass through this zone is reduced; inertial separation requires sufficient Δt for the droplet to complete the process of "shifting towards the wall → attaching"; when Δt is shortened, the droplet leaves with the airflow before it has fully adhered to the wall, resulting in a decrease in the capture rate.

[0101] Therefore, by splitting the same flow rate into two inlets, the speed of a single pipe is halved, which helps to keep the inertial impaction in the optimal Reynolds number range and maintain efficiency.

[0102] The cone section 23 of the cyclone separator has a taper of 1:3 to 1:5. The centrifugal force generated by the cyclone is positively correlated with the airflow velocity. By optimizing the taper and diameter ratio of the cone tube, the separation efficiency and resistance can be balanced.

[0103] Drain solenoid valves are installed at the five water outlets, and a water level sensor is installed in the water collection chamber 4. Both the water level sensor and the drain solenoid valves are connected to the vehicle's ECU via wiring. The drain solenoid valves and water level sensors are conventional technologies and are not shown in the figure.

[0104] During use, once the water level in the water collection chamber 4 reaches the threshold preset in the vehicle ECU, the vehicle ECU opens the drain solenoid valve to drain the accumulated water, ensuring timely drainage while utilizing the volume of the water collection chamber 4 to avoid frequent drainage operations.

[0105] This utility model also provides a corresponding gas-liquid separation method, which uses the above-mentioned gas-liquid separation device (and its usage method), and includes the following steps:

[0106] S1. Pre-separation stage: The gas-liquid mixture enters the coarse filter chamber 14 through the air inlet 9, and is guided to the I-shaped impact separation component through the radial flow guide component. Large droplets larger than 50μm are separated by inertial impact. The separated large droplets converge along the inclined baffle 13 at an angle of 5°~10°, enter the water collection chamber 15 through the water permeable hole 17, and then fall into the water collection chamber 4 through the water drop hole 8 of the transverse baffle 7.

[0107] S2. Fine separation stage: The gas pre-separated in S1 enters the hydrocyclone separator through the longitudinal partition plate 6 and the connecting port 16. It enters the cylindrical section 22 of the hydrocyclone separator along the tangential direction through the tangential channel 25, forming a vortex and using centrifugal force to separate small droplets smaller than 50μm. The separated small droplets flow downward along the inner wall of the cylindrical section 22 and the conical section 23, and directly flow into the water collection chamber 4 through the drain port 24. The gas enters the gas outlet chamber 11 upward through the inner cylinder 26.

[0108] S3. Gas purity control stage: The hydrogen concentration sensor in the middle of the exhaust chamber 11 detects the hydrogen concentration. When the concentration is lower than 99.97% (volume ratio), the vehicle ECU opens the exhaust solenoid valve of the impurity outlet 27 and closes the exhaust solenoid valve, using the pressure difference between the exhaust chamber 11 and atmospheric pressure to discharge the impurity gas; when the concentration is greater than or equal to 99.97%, the exhaust solenoid valve is closed and the exhaust solenoid valve is opened, so that the hydrogen resumes its normal path of being output to the downstream system through the exhaust port 12.

[0109] S4. Liquid discharge stage: The water level sensor in the water collection chamber 4 detects the water level. When the water level reaches the preset threshold, the vehicle ECU controls the drain solenoid valve to open and discharge the liquid in the water collection chamber 4. After completion, the drain solenoid valve is closed.

[0110] S1 and S2 are steps that are performed continuously during operation, while S3 and S4 are steps triggered by the vehicle ECU when the conditions are met during operation.

[0111] The I-shaped impact separation unit 19 and the radial guide plate 18 of the impact separation assembly are made of hydrogen corrosion resistant plastic material (such as polypropylene PP or polyvinylidene fluoride PVDF) with a thickness of 2-3 mm; the inclined baffle 13 and the transverse baffle 7 are made of modified PP material and the surface is hydrophobically treated (contact angle ≥100°) to reduce liquid adhesion.

[0112] The conical section 23 and inner cylinder 26 of the hydrocyclone separator are made of 316L stainless steel, with an inner wall roughness Ra≤1.6μm to reduce liquid residue.

[0113] This utility model also has the following advantages:

[0114] The pre-separation (i.e., coarse filtration, impact separation) stage efficiently separates large droplets: the radial guide plate 18 uniformly guides the gas-liquid mixture to the I-shaped impact separation unit 19, and the multiple bends of the impact separation channel 20 cause the droplets to collide with the side wall of the unit multiple times. Utilizing the principle of "velocity difference → inertia difference" (with the Reynolds number controlled in the optimal range of 2000~4000), the large droplets are thrown towards the wall surface; the inclined baffle 13 at an angle of 5°~10° promotes droplet confluence under the action of the component of gravity (flow velocity 0.5~1m / s), avoids low-angle liquid accumulation or high-angle secondary entrainment, and improves the separation efficiency of large droplets.

[0115] In the fine separation stage, small droplets are separated with low resistance: the tangential channel 25 causes the gas to form a strong swirling flow (tangential velocity 10-15 m / s) in the cylindrical section 22 and the conical section 23 (taper 1:3~1:5). The centrifugal force (F=mv² / r) throws the small droplets toward the inner wall. The inner cylinder 26 (diameter ratio 1:2~1:4) isolates the gas and liquid flow paths through "central drainage", avoiding the airflow from washing away the separated liquid, improving the separation efficiency of small droplets and reducing the secondary entrainment rate.

[0116] Precise control of gas purity: The concentration stratification phenomenon of "hydrogen accumulation in the upper middle and impurity gas accumulation in the lower middle" in the outlet chamber 11 enables the hydrogen concentration sensor in the middle to accurately capture purity changes. When the concentration is lower than 99.97%, it indicates that heavy gas (impurity gas) has accumulated at the hydrogen concentration sensor (located in the middle or upper part of the outlet chamber 11). At this time, the impurity gas is quickly discharged by utilizing the pressure difference (pressure in outlet chamber 11 > atmospheric pressure) (discharge time 2-3 seconds), ensuring that the purity of the output hydrogen meets the requirements of the fuel cell stack (≥99.97%) and avoiding the degradation of fuel cell stack performance caused by impurities.

[0117] Stable liquid discharge: The water level sensor in the water collection chamber 4 triggers drainage (water level threshold 150-200mL), with a single drainage time of 3-5s. Combined with the water collection chamber 4 volume of >200mL, the opening and closing frequency of the drainage solenoid valve is reduced (cycle 5-10min), reducing system power consumption and avoiding the risk of bacterial growth or freezing caused by liquid residue.

[0118] The inlet flow rate of the gas-liquid mixture is controlled at 8-12 m / s through dual inlets 9 to ensure that the inertial impaction is in the optimal Reynolds number range (Re=2000~4000), avoiding droplet breakage due to excessively high flow rate (>15 m / s) or reduced separation efficiency due to excessively low flow rate (<5 m / s).

[0119] The above embodiments are only used to illustrate and not limit the technical solutions of this utility model. Although the utility model has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the utility model without departing from the spirit and scope of the utility model. Any modifications or partial substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A device for gas-liquid separation, used in a hydrogen supply cycle system for a hydrogen fuel cell engine, characterized in that: The system includes an upper shell, to which a lower shell is sealed downwards. The lower shell is wider at the top and narrower at the bottom, and its side walls are inclined. The inner cavity of the lower shell forms a water collection chamber, and a water outlet is provided at the bottom end of the lower shell. The upper shell has a vertically arranged longitudinal partition in the middle, and the longitudinal partition is connected downward to a transverse partition for water permeability and air blocking. The transverse partition closes the top of the lower shell on one side of the longitudinal partition, and the transverse partition has a drain hole that is permeable from top to bottom. Above the transverse diaphragm, along the direction of airflow from upstream to downstream, there is a flow guiding component and an impact separation component. The upper housing adjacent to the flow guiding component is connected to an air inlet. The impact separation component is located between the flow guiding component and the longitudinal diaphragm. The longitudinal partition plate and the upper shell together form a fine filtration chamber on the other side of the air inlet, and a cyclone separator is provided in the fine filtration chamber; an air outlet chamber is provided between the cyclone separator and the top of the upper shell, and the air outlet end of the cyclone separator is connected to the air outlet chamber; an air outlet that is connected to the air outlet chamber is connected to the top wall of the upper shell in the middle of the air outlet chamber.

2. The apparatus for gas-liquid separation according to claim 1, characterized in that: The longitudinal diaphragm above the transverse diaphragm is connected to the inclined diaphragm. The inclined diaphragm, together with the longitudinal diaphragm above it and the upper shell, forms a coarse filtration chamber. The flow guiding assembly and the impact separation assembly are located in the coarse filtration chamber. The inclined diaphragm, together with the longitudinal diaphragm below it, the upper shell, and the transverse diaphragm, forms a water collection chamber. The longitudinal diaphragm is provided with a communication port that connects the inlet of the cyclone separator to the coarse filtration chamber. Taking the upstream and downstream direction of the airflow as a reference, the connection between the inclined baffle and the longitudinal baffle is the downstream end of the inclined baffle. The downstream end of the inclined baffle is lower than its upstream end. The downstream end of the inclined baffle is provided with water permeable holes that allow water to pass through from top to bottom. The inclined structure of the inclined baffle is used for the water that gathers on it to flow to the water permeable holes and enter the water collection chamber downwards. The water in the water collection chamber falls into the water collection chamber through the water drop holes.

3. The apparatus for gas-liquid separation according to claim 2, characterized in that: The air guide components are set one-to-one with the air inlets. The air guide components include several vertically arranged air guide plates. On the horizontal cross section, each air guide plate is evenly distributed in an arc shape with the intersection of the air inlet and the upper shell as the center, thus forming a radially evenly spaced structure. The impact separation assembly includes several impact separation units arranged at intervals. The horizontal cross-section of each impact separation unit is I-shaped, and the adjacent impact separation units form an impact separation channel with multiple bends. The upstream inlet of each impact separation channel is inclined towards the flow direction of the guide assembly. The downstream outlet of each impact separation channel is towards the longitudinal partition plate.

4. The apparatus for gas-liquid separation according to claim 2, characterized in that: Two cyclone separators are arranged side by side with a gap between them. The top of each cyclone separator is connected to the same partition plate. The circumferential edge of the partition plate is connected to the upper shell and the longitudinal partition plate. The partition plate, the upper shell and the longitudinal partition plate above it form the air outlet chamber. The upper part of the hydrocyclone separator is a cylindrical section, which is integrally connected to a conical section that is larger at the top and smaller at the bottom. The bottom end of the conical section is provided with a drain outlet that extends downward into the water collection chamber inside the lower shell. Each of the connecting ports corresponds to a hydrocyclone separator; each connecting port is connected to a tangential channel, and each tangential channel is connected to the cylindrical section of the corresponding hydrocyclone separator along the tangential direction. The cylindrical section of the cyclone separator has an inner cylinder coaxially arranged inside. The upper end of the inner cylinder is connected to the opening on the partition plate and serves as the outlet of the cyclone separator. The lower end of the inner cylinder is used for the airflow to enter the inner cylinder from bottom to top through the rotating flow and then flow to the outlet chamber. The inner cylinder is used to extend the path of the tangential airflow in the cyclone separator, thereby improving the efficiency of gas-liquid cyclone separation.

5. The apparatus for gas-liquid separation according to claim 4, characterized in that: The ratio of the diameter of the inner cylinder to the diameter of the cylindrical section of the cyclone separator is 1:2 to 1:4, so that the gas outlet velocity matches the cyclone intensity inside the cyclone separator.

6. The apparatus for gas-liquid separation according to claim 4, characterized in that: The outlet is connected to the downstream circulation pump or ejector inlet flange via an external outlet pipeline, and an outlet solenoid valve is installed on the outlet pipeline; a hydrogen concentration sensor is installed in the middle of the outlet chamber in the height direction; the pressure in the outlet chamber is higher than atmospheric pressure. The upper housing is also equipped with a miscellaneous gas outlet connected to the exhaust chamber. The miscellaneous gas outlet is used to install the exhaust solenoid valve, which is open to the atmosphere. The hydrogen concentration sensor, exhaust solenoid valve, and exhaust solenoid valve are all connected to the vehicle ECU via wiring. The vehicle ECU has a built-in lower limit of hydrogen concentration threshold MIN, where MIN = 99.97%. When the detection value of the hydrogen concentration sensor is less than MIN, the vehicle ECU opens the exhaust solenoid valve and closes the exhaust solenoid valve at the same time, using the pressure difference between the exhaust chamber and atmospheric pressure to discharge the impurity gas. When the detection value of the hydrogen concentration sensor is greater than or equal to MIN, the vehicle ECU closes the exhaust solenoid valve and opens the exhaust solenoid valve at the same time, allowing hydrogen to be output normally for use by the fuel cell system.

7. The apparatus for gas-liquid separation according to claim 3, characterized in that: Two air inlets are arranged side by side at intervals. Both air inlets are used to introduce unreacted hydrogen gas discharged from the anode outlet of the fuel cell stack. The two air inlets are used to reduce the hydrogen gas flow rate to keep the inertial impaction within the optimal Reynolds number range.

8. The apparatus for gas-liquid separation according to claim 6, characterized in that: The taper of the cone section of the cyclone separator is 1:3 to 1:

5.

9. The apparatus for gas-liquid separation according to any one of claims 1 to 8, characterized in that: A drain solenoid valve is installed at the water outlet, and a water level sensor is installed in the water collection chamber. Both the water level sensor and the drain solenoid valve are connected to the vehicle ECU via wiring.

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