Fuel cell atomizing and humidifying mixing device based on wind field particle size screening

Abstract

The application discloses a fuel cell atomization humidification mixing device based on wind field particle size screening, which comprises an outer shell, an inner core pipe and an atomizer. The outer shell is a hollow cavity structure, and an air inlet and an air outlet are arranged at the bottom and the top of the outer shell respectively and communicate with the inner cavity of the outer shell. The inner core pipe is coaxially arranged in the outer shell, and an annular air duct is formed between the outer wall of the inner core pipe and the inner wall of the outer shell. A mixing cavity is formed between the upper end of the inner core pipe and the air outlet of the outer shell. The inner core pipe has an atomization cavity arranged at the lower part of the inner core pipe and a wind field particle size screening cavity extending upward from the atomization cavity and communicating with the mixing cavity. A low-speed air inlet guide port is arranged on the pipe wall of the inner core pipe at the junction of the atomization cavity and the wind field particle size screening cavity. The atomizer is installed in the atomization cavity. The application realizes non-contact precise grading screening of atomized droplets through controllable laminar flow wind field, and solves the problem of water flooding of the electric pile caused by large droplet entrainment and agglomeration through the design of an anti-agglomeration structure in the whole process.

Description

Technical Field

[0001] This invention relates to the field of proton exchange membrane fuel cell technology, and specifically to a fuel cell atomization humidification and mixing device based on wind field particle size screening. Background Technology

[0002] The power generation efficiency, operational stability, and lifespan of a proton exchange membrane fuel cell are highly dependent on the precise control of the humidity, temperature, and pressure parameters of the cathode intake air. Too low intake humidity will cause the proton exchange membrane to dry out, internal resistance to increase, and output power to decrease. Too high humidity or the presence of large-diameter liquid droplets will cause water flooding in the stack flow channels and catalytic layer, resulting in voltage fluctuations in a single cell and, in severe cases, damage to the core components of the stack.

[0003] Currently, air-side humidification in fuel cells mainly falls into two technical routes: membrane humidification and atomization humidification. Existing technologies have the following core drawbacks:

[0004] 1. Membrane humidification solution: This solution relies on the infiltration of humidified air from the tail of the fuel cell stack to achieve passive humidification. However, it suffers from adjustment lag and cannot quickly respond to the humidity requirements under varying load conditions of the fuel cell stack. Furthermore, the controllability of the humidification amount is poor, making it difficult to achieve precise closed-loop control of humidity.

[0005] 2. Conventional atomization humidification solutions: While possessing advantages such as active adjustment and fast response speed, they have fatal shortcomings: First, the atomized droplets have a wide original particle size distribution, inevitably producing large droplets with a diameter of over 10μm. During the mixing process, these droplets are prone to collision and coalescence, forming even larger droplets that can cause flooding after entering the fuel cell stack. Second, existing mixing chambers only have basic gas-liquid mixing functions and lack effective particle classification and screening structures, making it impossible to intercept / separate large droplets. A few solutions that use filter screens for interception are prone to problems such as filter screen clogging, sudden increase in system pressure drop, and high maintenance costs, failing to meet the long-term continuous operation requirements of fuel cells.

[0006] The existing fuel cell atomizing humidification mixing device has design flaws: (1) It mostly adopts counter-current and cross-flow structure, with high relative velocity between droplets and airflow, resulting in a high probability of collision and aggregation; at the same time, there are dead zones and low-speed stagnation zones in the flow field, which easily cause droplet wall adhesion, stagnation and aggregation, resulting in uneven gas-liquid mixing. (2) When the high-frequency ultrasonic atomizing plate is working, it will generate a central water column of more than 15cm. Large droplets directly splash into the main flow channel, further aggravating the risk of droplet aggregation and flooding. The existing structure does not have an effective solution for water jet guidance and pre-separation. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a fuel cell atomization humidification and mixing device based on wind field particle size screening. It achieves non-contact and precise classification and screening of atomized droplets through a controllable laminar flow wind field. Combined with a full-process anti-agglomeration structure design, it fundamentally solves the problem of fuel cell stack flooding caused by large droplet entrainment and agglomeration.

[0008] This invention provides a fuel cell atomization humidification and mixing device based on wind field particle size screening, comprising:

[0009] The outer shell is a hollow cavity structure, with an air inlet and an air outlet communicating with its inner cavity at the bottom and top of the outer shell, respectively.

[0010] The inner core tube is coaxially disposed within the outer shell. An annular air duct is formed between the outer wall of the inner core tube and the inner wall of the outer shell. A mixing chamber is formed between the upper end of the inner core tube and the air outlet of the outer shell. The inner core tube has an atomizing chamber located at its lower part and an air field particle size screening chamber extending upward from the atomizing chamber and connecting to the mixing chamber. A low-speed air inlet guide is provided on the tube wall of the inner core tube at the junction of the atomizing chamber and the air field particle size screening chamber.

[0011] Atomizer, which is installed inside the atomizing chamber, is used to atomize the water introduced into the atomizing chamber;

[0012] A small amount of airflow outside the inner core tube can enter the wind field particle size screening chamber through the low-speed air inlet guide port and form an upward-flowing low-speed airflow. The low-speed airflow can blow the fine droplets generated by atomization upward, but cannot prevent the large droplets generated by atomization from settling downward.

[0013] Furthermore, a rectifier screen is provided inside the air inlet of the outer casing.

[0014] Furthermore, the mixing chamber is provided with guide vanes for generating swirling flow in the passing airflow.

[0015] Furthermore, the guide vane has a guide angle of 15-20°.

[0016] Furthermore, the low-speed air intake guide ports are evenly distributed around the inner core tube.

[0017] Furthermore, the particle size of the fine droplets is <10μm, and the particle size of the large droplets is ≥10μm.

[0018] Furthermore, the inner peripheral wall of the lower end of the air field particle size screening chamber of the inner core tube is connected to a tapered water guide ring that gradually decreases in size from top to bottom.

[0019] Furthermore, the atomizer is an ultrasonic atomizer.

[0020] Furthermore, the inner cavity of the outer shell has a straight section, a lower constriction section that gradually narrows downward from the lower end of the straight section and is connected to the air inlet, and an upper constriction section that gradually narrows upward from the upper end of the straight section and is connected to the air outlet. The lower end of the inner core tube is provided with a conical head placed in the lower constriction section.

[0021] Furthermore, multiple circumferentially spaced support plates are provided between the straight cylindrical section and the lower constricted section of the outer shell and the inner core tube.

[0022] The beneficial effects of this invention are reflected in:

[0023] The atomizing humidification mixing device of the present invention is used in the humidification system of a fuel cell. The air inlet is connected to the output end of the compressor of the fuel cell humidification system, and the air outlet is connected to the air supply port of the fuel cell stack. During operation, the high-temperature, high-pressure dry air generated by the compressor enters the inner cavity of the outer shell through the air inlet at the lower end of the device. Most of the airflow flows upward along the annular air duct between the outer shell and the inner core tube. A small amount of airflow enters the internal airflow particle size screening chamber through the low-speed air inlet on the inner core tube wall, forming a stable upward low-speed airflow within the airflow particle size screening chamber. Simultaneously, the ultrasonic atomizer in the atomization chamber atomizes the water, producing atomized droplets of different sizes. These droplets, mixed with the airflow, enter the airflow particle size screening chamber upward together. The fine droplets produced by atomization are relatively light and are carried out of the airflow particle size screening chamber by the low-speed airflow. The central water column and large-diameter droplets produced by atomization are heavier and settle back into the atomization chamber before flying out of the airflow particle size screening chamber, achieving non-contact, precise grading and screening of atomized droplets. The qualified fine droplets after screening enter the mixing chamber and are fully mixed with the high-temperature, high-pressure dry air rising through the annular air duct. Finally, humidified air with uniform humidity and no large droplets is output from the top air outlet to supply the fuel cell stack.

[0024] Compared to existing technologies, this invention relies on a low-speed airflow to achieve precise droplet size sieving, actively intercepting large droplets of 10μm and above. This prevents large droplets from entering the fuel cell stack at the source, completely solving the problems of flow channel blockage and flooding of the catalyst layer and proton exchange membrane caused by large droplet entrainment and droplet aggregation, ensuring stable stack operation. It uses airflow sorting instead of traditional filter interception, eliminating problems of filter blockage and increased pressure drop, requiring no frequent maintenance, and adapting to the long-term continuous operation requirements of fuel cells. The overall layered flow channel design ensures smooth airflow with fewer dead zones and low-speed stagnation areas, significantly reducing the probability of droplet adhesion to the wall and collision agglomeration, ensuring stable atomized droplet size, and thus ensuring uniform gas-liquid mixing and improving humidification control accuracy. Addressing the industry pain point of ultrasonic atomized water column splashing, this invention isolates the atomization channel from the main airflow channel by setting an inner core tube, achieving pre-separation and backflow of the atomized water column from large droplets, preventing large droplets from directly entering the main channel, further reducing the risk of droplet aggregation, and improving the operational stability of the atomization system. Attached Figure Description

[0025] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0026] Figure 1 This is an external perspective view of an embodiment of the present invention;

[0027] Figure 2 This is a vertical axonometric sectional view of an embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of the airflow direction according to an embodiment of the present invention.

[0029] In the attached diagram, 100-outer shell; 110-air inlet; 120-air outlet; 130-annular air duct; 140-mixing chamber; 150-straight section; 160-lower constriction section; 170-upper constriction section; 180-support plate; 200-inner core tube; 210-atomizing chamber; 220-airflow particle size screening chamber; 230-low-speed air inlet guide; 240-conical water guide ring; 250-conical head; 300-atomizer; 400-rectifier screen; 500-guide blades. Detailed Implementation

[0030] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0031] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0032] like Figures 1-3 As shown, this embodiment of the invention provides a fuel cell atomization humidification and mixing device based on wind field particle size screening, including an outer shell 100, an inner core tube 200 and an atomizer 300.

[0033] The outer shell 100 is a hollow cavity structure, and the bottom and top of the outer shell 100 are respectively provided with an air inlet 110 and an air outlet 120 communicating with its inner cavity.

[0034] In this embodiment, the air inlet 110 at the bottom of the outer casing 100 is used to connect to the compressor output of the fuel cell humidification system. The compressor can compress external air into high-temperature and high-pressure dry air and introduce it into the air inlet 110. The air inlet 110 of the outer casing 100 is equipped with a rectifier mesh 400 to eliminate vortices and deflection of the input high-pressure airflow, providing a uniform and stable straight laminar flow for subsequent wind field screening. At the same time, the outer wall is wrapped with a heat insulation layer to reduce the impact of temperature drop on the humidification and screening effect. The air inlet 110 of the outer casing 100 is equipped with a pressure sensor and a temperature sensor to collect airflow parameters in real time and adapt to the closed-loop control of the system.

[0035] The inner core tube 200 is coaxially disposed inside the outer shell 100. An annular air duct 130 is formed between the outer wall of the inner core tube 200 and the inner wall of the outer shell 100. A mixing chamber 140 is formed between the upper end of the inner core tube 200 and the air outlet 120 of the outer shell 100. The inner core tube 200 has an atomizing chamber 210 located at its lower part and an air field particle size screening chamber 220 extending upward from the atomizing chamber 210 and connecting to the mixing chamber 140. The inner wall of the air field particle size screening chamber 220 is mirror polished and superhydrophobic. A low-speed air inlet guide port 230 is provided on the tube wall of the inner core tube 200 at the junction of the atomizing chamber 210 and the air field particle size screening chamber 220.

[0036] The atomizer 300 is installed inside the atomizing chamber 210 to atomize the water entering the atomizing chamber 210. Specifically, the atomizer 300 is a 2.4MHz high-frequency ultrasonic atomizer.

[0037] It should be noted that a water level sensor is installed inside the atomizing chamber 210 in this embodiment. The water level in the atomizing chamber 210 needs to be monitored in real time by the water level sensor, so as to control the replenishment system to replenish water to the atomizing chamber 210 in real time. The outer shell 100 and the inner core tube 200 are provided with holes through which the wires of the atomizer 300 and the water level sensor, as well as the water pipes of the water replenishment system, pass.

[0038] In this embodiment, the low-speed air inlet guide ports 230 are evenly distributed around the inner core tube 200 to ensure that the airflow can enter the wind field particle size screening chamber 220 evenly through the low-speed air inlet guide ports 230.

[0039] A small amount of airflow outside the inner core tube 200 can enter the wind field particle size screening chamber 220 through the low-speed air inlet guide port 230 and form an upward-flowing low-speed airflow. The low-speed airflow can blow the fine droplets generated by atomization upward, but cannot prevent the large droplets generated by atomization from settling downward. Here, the particle size of the fine droplets is <10μm, and the particle size of the large droplets is ≥10μm.

[0040] The principle of screening atomized droplet size in this embodiment is based on Stokes' sedimentation law: 10μm is set as the critical screening particle size. At 20℃ and normal pressure, the terminal settling velocity of a 10μm pure water droplet is about 0.003m / s. By matching the height H of the wind field particle size screening chamber 220 with the critical wind speed, large droplets ≥10μm settle to the bottom atomization chamber 210 before flying out of the wind field particle size screening chamber 220. Fine droplets <10μm are completely carried through by the low-speed airflow, achieving non-contact precise classification and screening.

[0041] When the high-temperature, high-pressure dry air introduced by the compressor flows upward along the outer casing 100, it creates a pressure difference: the pressure is lower near the upper end of the inner core tube 200 and higher near the lower end of the annular air duct 130. This causes a small portion of the airflow passing through the annular air duct 130 to enter the inner core tube 200 through the low-speed air inlet guide port 230, thus forming an upward-flowing low-speed airflow within the particle size screening chamber 220. The velocity of this low-speed airflow is controlled by the area of ​​the low-speed air inlet guide port 230. Generally, the actual design velocity of the low-speed airflow is taken as 80% of the calculated critical velocity, leaving a safety margin to avoid screening failure due to environmental disturbances.

[0042] The fine mist droplets carried by the low-speed airflow are mixed with the high-temperature, high-pressure dry air passing through the annular air duct 130 and then enter the mixing chamber 140. In some embodiments, the mixing chamber 140 is provided with guide vanes 500 for generating swirling flow in the airflow. The guide vanes 500 are arc-shaped guide vanes without sharp corners, and 3-4 vanes are evenly arranged along the circumference of the inner wall of the mixing chamber 140. The guide angle of the guide vanes 500 is 15-20°, which can generate weak swirling flow in the airflow, which is beneficial to enhance the thorough mixing of high-temperature, high-pressure dry air and fine mist droplets, and utilize the residual heat of the high-temperature, high-pressure air to achieve rapid vaporization of the mist droplets.

[0043] When large droplets settle in the particle size screening chamber 220, they will adhere to the inner wall of the inner core tube 200 and flow back. In order to prevent the water flowing back along the inner wall of the inner core tube 200 from flowing out of the inner core tube 200 through the low-speed air inlet guide port 230, a tapered water guide ring 240 that gradually decreases in size from top to bottom is connected to the inner peripheral wall of the particle size screening chamber 220 of the inner core tube 200.

[0044] In some embodiments, the inner cavity of the outer casing 100 has a straight section 150, a lower constriction section 160 that gradually narrows downward from the lower end of the straight section 150 and is connected to the air inlet 110, and an upper constriction section 170 that gradually narrows upward from the upper end of the straight section 150 and is connected to the air outlet 120. The lower end of the inner core tube 200 is provided with a conical head 250 placed in the lower constriction section 160.

[0045] In this embodiment, the straight section 150 of the outer shell 100 is connected to the air inlet 110 through the lower constriction section 160. The air inlet 110 matches the standard pipe diameter of the fuel cell humidification system and can be directly connected to the air supply line of the compressor. At the same time, the lower end of the inner core tube 200 is provided with a conical head 250 that extends into the lower constriction section 160, which can evenly distribute the high-temperature, high-pressure dry air introduced from the air inlet 110 to the annular air duct 130.

[0046] Meanwhile, the straight section 150 of the outer casing 100 is connected to the outlet 120 via the upper constriction section 170, which smoothly transitions the gas-liquid two-phase flow to weakly turbulent / laminar flow, eliminating parameter fluctuations caused by abrupt changes in the flow field. The constriction ratio of the upper constriction section 170 is 2:1-3:1, and the outlet 120 matches the standard pipe diameter of the fuel cell humidification system, allowing direct connection to subsequent membrane humidifiers and fuel cell stack inlet pipes. Humidity sensors, temperature sensors, and pressure sensors are installed at the outlet 120 to provide real-time feedback signals for the system's closed-loop control.

[0047] In order to support and fix the inner core tube 200 inside the outer shell 100, and to form an annular air duct 130 between the outer wall of the inner core tube 200 and the inner wall of the outer shell 100, a plurality of circumferentially spaced support plates 180 are provided between the straight section 150 and the lower constricted section 160 of the outer shell 100 and the inner core tube 200.

[0048] The atomizing humidification mixing device of this invention is used in the humidification system of a fuel cell. The inlet 110 of the device is connected to the output of the compressor in the fuel cell humidification system, and the outlet 120 is connected to the air supply port of the fuel cell stack. During operation, the high-temperature, high-pressure dry air generated by the compressor enters the inner cavity of the outer casing 100 through the inlet 110. Most of the airflow flows upward along the annular air duct 130 between the outer casing 100 and the inner core tube 200. A small amount of airflow enters the internal airflow particle size screening chamber 220 through the low-speed air intake guide port 230 on the wall of the inner core tube 200, forming a stable upward low-speed airflow within the airflow particle size screening chamber 220. Simultaneously, the atomizer 300 in the atomizing chamber 210 atomizes the water, producing atomized droplets of different sizes, which mix with the airflow and enter the airflow particle size screening chamber 220. In the particle size screening chamber 220, the light fine droplets generated by atomization are enveloped and carried out of the wind field particle size screening chamber 220 by a low-speed airflow. The central water column and large-diameter droplets generated by atomization are heavier and settle back into the atomization chamber 210 before flying out of the wind field particle size screening chamber 220, realizing non-contact precise classification and screening of atomized droplets. The qualified fine droplets after screening enter the mixing chamber 140 and are fully mixed with the high-temperature and high-pressure dry air rising from the annular air duct 130. Finally, humidified air with uniform humidity and no large droplets is output from the top air outlet 120 to supply fuel cell stacks.

[0049] Compared to existing technologies, this invention relies on a low-speed wind field to achieve precise droplet size sieving, actively intercepting large droplets of 10μm and above. This prevents large droplets from entering the fuel cell stack at the source, completely solving the problems of flow channel blockage and flooding of the catalyst layer and proton exchange membrane caused by large droplet entrainment and droplet aggregation, ensuring stable operation of the stack. It uses airflow sorting instead of traditional filter interception, eliminating the problems of filter blockage and increased pressure drop, requiring no frequent maintenance, and adapting to the long-term continuous operation requirements of fuel cells. The overall design employs a layered flow channel system. The design ensures smooth airflow with fewer dead zones and low-speed stagnation areas, significantly reducing the probability of droplet adhesion to the wall, collision, and agglomeration. This guarantees stable droplet size and ensures uniform gas-liquid mixing, improving humidification control accuracy. Addressing the industry pain point of splashing in ultrasonic atomized water columns, this invention isolates the atomization channel from the main airflow channel by setting an inner core tube 200. This achieves pre-separation and backflow of the atomized water column and large droplets, preventing large droplets from directly entering the main channel, further reducing the risk of droplet aggregation, and improving the operational stability of the atomization system.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A fuel cell atomization humidification and mixing device based on wind field particle size screening, characterized in that, include: The outer shell is a hollow cavity structure, with an air inlet and an air outlet communicating with its inner cavity at the bottom and top of the outer shell, respectively. The inner core tube is coaxially disposed within the outer shell. An annular air duct is formed between the outer wall of the inner core tube and the inner wall of the outer shell. A mixing chamber is formed between the upper end of the inner core tube and the air outlet of the outer shell. The inner core tube has an atomizing chamber located at its lower part and an air field particle size screening chamber extending upward from the atomizing chamber and connecting to the mixing chamber. A low-speed air inlet guide is provided on the tube wall of the inner core tube at the junction of the atomizing chamber and the air field particle size screening chamber. Atomizer, which is installed inside the atomizing chamber, is used to atomize the water introduced into the atomizing chamber; A small amount of airflow outside the inner core tube can enter the wind field particle size screening chamber through the low-speed air inlet guide port and form an upward-flowing low-speed airflow. The low-speed airflow can blow the fine droplets generated by atomization upward, but cannot prevent the large droplets generated by atomization from settling downward.

2. The fuel cell atomization humidification and mixing device based on wind field particle size screening according to claim 1, characterized in that, The air inlet of the outer casing is equipped with a rectifier mesh.

3. The fuel cell atomization humidification and mixing device based on wind field particle size screening according to claim 1, characterized in that, The mixing chamber is equipped with guide vanes for generating swirling flow in the passing airflow.

4. The fuel cell atomization humidification and mixing device based on wind field particle size screening according to claim 3, characterized in that, The guide vane has a guide angle of 15-20°.

5. The fuel cell atomization humidification and mixing device based on wind field particle size screening according to claim 1, characterized in that, The low-speed air intake inlets are evenly distributed around the inner core tube.

6. The fuel cell atomization humidification and mixing device based on wind field particle size screening according to claim 1, characterized in that, The micro-droplets have a particle size of <10μm, and the large droplets have a particle size of ≥10μm.

7. The fuel cell atomization humidification and mixing device based on wind field particle size screening according to claim 1, characterized in that, The inner wall of the lower end of the particle size screening chamber of the inner core tube is connected to a tapered water guide ring that gradually decreases in size from top to bottom.

8. The fuel cell atomization humidification and mixing device based on wind field particle size screening according to claim 1, characterized in that, The atomizer is an ultrasonic atomizer.

9. The fuel cell atomization humidification and mixing device based on wind field particle size screening according to claim 1, characterized in that, The inner cavity of the outer shell has a straight section, a lower constriction section that gradually narrows downward from the lower end of the straight section and is connected to the air inlet, and an upper constriction section that gradually narrows upward from the upper end of the straight section and is connected to the air outlet. The lower end of the inner core tube is provided with a conical head placed in the lower constriction section.

10. The fuel cell atomization humidification and mixing device based on wind field particle size screening according to claim 9, characterized in that, Multiple circumferentially spaced support plates are provided between the straight cylindrical section and the lower constricted section of the outer shell and the inner core tube.

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