Multi-stage ejector for hydrogen fuel cell power system and hydrogen fuel cell power system
By designing a multi-stage ejector, including structures such as a jet tube, a return tube, a capillary airflow channel and a mesh partition, the problem of low hydrogen and oxygen mixing efficiency in the hydrogen fuel cell power system was solved, and efficient gas mixing and fuel cell performance improvement were achieved.
Patent Information
- Application Number
- CN202422805782.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-18
- Publication Date
- 2025-09-26
- Estimated Expiration
- 2034-11-18
AI Technical Summary
The ejector mixing efficiency in existing hydrogen fuel cell power systems is low, resulting in insufficient contact between hydrogen and oxygen, affecting the chemical reaction rate and the output power of the fuel cell.
A multi-stage ejector is designed, including first-stage, second-stage and third-stage ejectors. Through structures such as ejector tubes, return tubes, capillary airflow channels, mesh partitions and splitters, multi-stage mixing of ejector gas and return gas is achieved to improve mixing efficiency.
It significantly improves the mixing effect of hydrogen and oxygen, improves the power performance and working efficiency of hydrogen fuel cells, and ensures the stability and safety of the system.
Smart Images
Figure CN223387647U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of fuel cells, in particular to a multi-stage ejector for a hydrogen fuel cell power system and a hydrogen fuel cell power system. Background Art
[0002] In today's society, with the increasing demand for clean energy and growing concerns about environmental impact, hydrogen fuel cells have attracted widespread attention as efficient and clean energy conversion devices. They generate electricity through a chemical reaction between hydrogen and oxygen, with water as the only byproduct. Therefore, they are considered an ideal alternative to traditional fossil fuels. However, despite their many advantages, hydrogen fuel cells still face several challenges in their practical application, particularly in optimizing the power system.
[0003] The ejector, a key component in hydrogen fuel cell power systems, plays a crucial role in improving overall system performance. The ejector facilitates the mixing of hydrogen and oxygen (typically from air), which is crucial for ensuring the efficient chemical reactions within the fuel cell. Ideal mixing maximizes the utilization of the input hydrogen and oxygen, thereby improving energy conversion efficiency and overall system performance. However, the ejector in existing hydrogen fuel cell power systems suffers from low mixing efficiency, which directly limits the fuel cell's power output.
[0004] Specifically, poor mixing efficiency means that hydrogen and oxygen don't fully come into contact, resulting in excess hydrogen or oxygen in some areas and insufficient reactants in others. This uneven distribution reduces the rate and efficiency of the chemical reaction, ultimately affecting the fuel cell's output power. Therefore, designing an ejector that effectively improves hydrogen and oxygen mixing efficiency has become a key technical challenge in improving the performance of hydrogen fuel cell power systems. Utility Model Content
[0005] In response to the problem of low mixing efficiency of the ejector, the utility model provides a multi-stage ejector and a hydrogen fuel cell power system for a hydrogen fuel cell power system. By setting a first-stage ejector, a second-stage ejector and a third-stage ejector, the jet gas and the return gas are mixed in multiple stages, thereby improving the mixing efficiency of the ejector.
[0006] The utility model achieves the above technical objectives through the following technical means.
[0007] A multi-stage ejector for a hydrogen fuel cell power system, comprising a first-stage ejector, a second-stage ejector, and a third-stage ejector connected in sequence along an airflow direction;
[0008] The first-stage ejector has a first-stage mixing cavity with one end open, and a housing of the first-stage ejector is provided with a jet pipe and a return pipe communicating with the first-stage mixing cavity;
[0009] The secondary ejector has a secondary mixing cavity with an open end. The left side of the secondary ejector is docked with the right side of the primary ejector and blocks the right opening of the primary mixing cavity. A capillary airflow channel for connecting the primary mixing cavity and the secondary mixing cavity is provided on the secondary ejector housing in contact with the primary mixing cavity. A plurality of mesh partitions are provided in the secondary mixing cavity along the airflow direction, and the mesh partitions divide the secondary mixing cavity into a plurality of small chambers.
[0010] The three-stage ejector has a three-stage mixing cavity with an open end, and the open end of the three-stage mixing cavity of the three-stage ejector is connected to the secondary mixing cavity of the secondary ejector; a diverter is provided in the three-stage mixing cavity, and an outlet pipe for drawing out the mixed gas is provided on the three-stage ejector housing on the right side of the three-stage mixing cavity;
[0011] After the first-stage ejector is docked with the second-stage ejector and the second-stage ejector is docked with the third-stage ejector, the jet tube, the first-stage mixing cavity, the second-stage mixing cavity and the third-stage mixing cavity are in a coaxial communication state from left to right.
[0012] Furthermore, the secondary ejector shell in contact with the primary mixing cavity has a coaxially arranged first curved surface, a second curved surface and a third curved surface; the first curved surface is trumpet-shaped, the outer diameter of the first curved surface is greater than its inner diameter, and diverges toward the side of the secondary mixing cavity; the second curved surface is trumpet-shaped, the outer diameter of the second curved surface is greater than its inner diameter, and diverges toward the side of the primary mixing cavity; the outer circle edge of the second curved surface is connected with the inner circle edge of the first curved surface; the third curved surface is a conical surface and faces the side of the primary mixing cavity, and the outer circle edge of the third curved surface is connected with the inner circle edge of the second curved surface; the capillary airflow channel is a branched parallel pipe structure, having multiple air inlets and the same air outlet, and the multiple air inlets are evenly distributed circumferentially on the first curved surface and the third curved surface.
[0013] Furthermore, the cross section of the branch pipe of the capillary airflow channel is circular, and its diameter is 10-20 mm; or the cross section of the branch pipe of the capillary airflow channel is elliptical, and its major axis is 10-20 mm.
[0014] Furthermore, the branch pipes of the capillary airflow channel are spiral or wavy pipe structures, and the inner diameter of the pipes near the air outlet gradually decreases along the airflow direction.
[0015] Furthermore, the thickness of the mesh separator is 0.1-0.5 mm, the spacing between adjacent mesh separators is 1-5 mm, and the diameter of the micropores on the mesh separator is 50-200 μm.
[0016] Furthermore, the mesh separator is made of polytetrafluoroethylene or polyimide; the mesh separator is provided with a hydrophobic coating with a thickness of 20 to 30 μm, and the material of the hydrophobic coating is polydimethylsiloxane.
[0017] Furthermore, the inner diameter of the three-stage mixing cavity between the splitter and the air outlet pipe gradually decreases along the air flow direction, and the inner diameter of the air outlet pipe is 3-5 mm.
[0018] Furthermore, a pore network is provided in the primary mixing cavity, and the pore network is composed of a plurality of nickel alloy wires arranged in an alternating manner; the diameter of the nickel alloy wire is 0.1~0.9mm, and the arrangement manner is random arrangement or matrix arrangement, and a plurality of protrusions are provided on the nickel alloy wire.
[0019] Furthermore, the connection between the first-stage ejector and the second-stage ejector is a threaded connection, and the connection between the second-stage ejector and the third-stage ejector is a flange connection, and sealing gaskets are provided at the connection positions.
[0020] A hydrogen fuel cell power system comprising a multi-stage ejector as described above.
[0021] This utility model significantly improves the mixing efficiency of the jet and return gas by designing a three-stage ejector. First, the jet and return gas are introduced into the primary mixing chamber through the jet and return pipes, respectively, for initial mixing. This stage of mixing relies primarily on the suction effect created by the high-speed flow of the jet gas, drawing the return gas into the primary mixing chamber and achieving initial mixing.
[0022] The mixed gases then enter the capillary flow channel, where they undergo secondary mixing through the diversion and confluence of the capillary flow channel. The unique design of the capillary flow channel, including the branched parallel pipe structure, the spiral or wavy structure of the branch pipes, and the gradual reduction of the pipe inner diameter along the airflow direction, further refines the airflow and increases the contact area between gas molecules, thereby significantly improving the mixing effect.
[0023] Next, after fine mixing in the capillary flow channel, the airflow flows into the secondary mixing chamber. During this process, the airflow passes through the micropores in the mesh partitions within the secondary mixing chamber, forming tiny vortices. These tiny vortices not only further break up large particles in the airflow but also promote deeper mixing between gas molecules, achieving a more uniform mixing effect.
[0024] Finally, after deep mixing in the secondary mixing chamber, the airflow enters the tertiary mixing chamber. Within the tertiary mixing chamber, the airflow is rectified by a flow divider to ensure even distribution. The rectified airflow is mixed again in the outlet pipe before exiting the ejector, ultimately forming a highly uniform gas mixture. This provides high-quality fuel for the hydrogen fuel cell, significantly improving its power performance and efficiency.
[0025] The beneficial effects of the utility model are as follows:
[0026] The utility model realizes effective mixing of the jet gas and the return gas through the design of the multi-stage ejector, improves the mixing efficiency, and helps to improve the working performance of the hydrogen fuel cell.
[0027] The utility model improves the secondary ejector shell by changing the common plane structure into a multi-layer curved surface structure. The design of these curved surfaces makes the gas flow path smoother, reduces the pressure loss caused by sudden changes, and can guide the gas to form a certain pre-mixing effect before entering the capillary flow channel.
[0028] The use of the mesh partition in the present invention not only increases the turbulence effect in the secondary mixing cavity and promotes sufficient mixing between gases, but also can effectively adjust the gas flow state by controlling the thickness, spacing and pore size of the mesh partition, thereby enhancing the stability and reliability of the system.
[0029] The utility model selects polytetrafluoroethylene or polyimide with good corrosion resistance as the mesh partition material, and applies a hydrophobic coating on its surface, which not only extends the service life of the equipment, but also reduces the impact of moisture on the mixed gas, ensuring the safety and stability of the hydrogen fuel cell operation.
[0030] The pore network within the primary mixing chamber of this invention significantly enhances the turbulent flow of the gas, and the raised structures on the fiber bundles further increase the irregularity of the gas flow, generating more turbulence and eddies. These turbulence and eddies allow the jet gas and the return gas to fully contact and disperse within the primary mixing chamber, accelerating the mixing process and improving mixing efficiency.
[0031] The utility model adopts threaded connection and flange connection to connect the ejectors of each level, which is not only convenient for assembly and maintenance, but also ensures the sealing of the connection parts through the sealing gasket, prevents leakage, and ensures the safe operation of the system. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] Figure 1 This is a cross-sectional view of the multi-stage ejector for the hydrogen fuel cell power system described in the present invention.
[0033] Figure 2It is a three-dimensional diagram of the secondary ejector described in the utility model.
[0034] Figure 3 This is an assembly diagram of the mesh partition described in the utility model in the secondary mixing cavity.
[0035] Figure 4 This is a schematic structural diagram of the pore network described in the present invention.
[0036] The reference numerals are as follows:
[0037] 1-first-stage ejector; 2-second-stage ejector; 3-third-stage ejector; 4-jet tube; 5-return tube; 6-capillary flow channel; 7-mesh partition; 8-diverter; 9-outlet pipe. DETAILED DESCRIPTION
[0038] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.
[0039] Example 1
[0040] The multi-stage ejector for the hydrogen fuel cell power system described in this embodiment includes a first-stage ejector 1, a second-stage ejector 2, and a third-stage ejector 3 connected in sequence from left to right along the airflow direction. Figure 1 This is a cross-sectional view of the multi-stage ejector for the hydrogen fuel cell power system described in this embodiment.
[0041] The primary ejector 1 has a primary mixing cavity. A jet tube 4 for introducing jet gas is provided on the housing of the primary ejector 1 on the left side of the primary mixing cavity. A return tube 5 for introducing return gas is provided on the housing of the primary ejector 1 at the top / bottom of the primary mixing cavity. The right side of the primary mixing cavity is open.
[0042] The secondary ejector 2 has a secondary mixing cavity, and the left side of the secondary ejector 2 is docked with the right side of the primary ejector 1 and blocks the right opening of the primary mixing cavity. Specifically, the shell of the secondary ejector 2 in contact with the primary mixing cavity has a coaxially arranged first curved surface, a second curved surface and a third curved surface. The first curved surface is trumpet-shaped, the outer diameter of the first curved surface is greater than its inner diameter, and diverges toward the side of the secondary mixing cavity. The second curved surface is trumpet-shaped, the outer diameter of the second curved surface is greater than its inner diameter, and diverges toward the side of the primary mixing cavity. The outer circle edge of the second curved surface is connected with the inner circle edge of the first curved surface. The third curved surface is a conical surface and faces the side of the primary mixing cavity. The outer circle edge of the third curved surface is connected with the inner circle edge of the second curved surface. Figure 2This is a three-dimensional view of the secondary ejector 2 described in this embodiment. The secondary ejector 2 housing, which contacts the primary mixing cavity, is provided with a capillary flow channel 6 for connecting the primary and secondary mixing cavities. The capillary flow channel 6 is a branched parallel pipe structure with multiple air inlets and a common air outlet. The multiple air inlets are evenly distributed circumferentially on the first and third curved surfaces. The branch pipes of the capillary flow channel 6 are circular in cross-section with a diameter of 10-20 mm. The branch pipes of the capillary flow channel 6 have a wavy pipe structure, with the inner diameter of the pipe gradually decreasing near the air outlet along the direction of airflow. Several mesh partitions 7 are provided in the secondary mixing cavity along the direction of airflow. These mesh partitions 7 divide the secondary mixing cavity into several small chambers. The thickness of the mesh partitions 7 is 0.1-0.5 mm, the spacing between adjacent mesh partitions 7 is 1-5 mm, and the pore size of the micropores on the mesh partitions 7 is 50-200 μm. The mesh separator 7 is made of polytetrafluoroethylene or polyimide, and has a polydimethylsiloxane coating with a thickness of 20-30 μm. Figure 3 This is an assembly diagram of the mesh partition plate 7 in the secondary mixing cavity of this embodiment. The right side of the secondary mixing cavity is in an open state.
[0043] The tertiary ejector 3 has a tertiary mixing cavity. The left side of the tertiary ejector 3 is docked with the right side of the secondary ejector 2. The left side of the tertiary mixing cavity is open, allowing the secondary mixing cavity and the tertiary mixing cavity to communicate after the tertiary ejector 3 and the secondary ejector 2 are docked. A diverter 8 is provided in the tertiary mixing cavity. An outlet pipe 9 for discharging the mixed gas is provided on the housing of the tertiary ejector 3 on the right side of the tertiary mixing cavity. The inner diameter of the tertiary mixing cavity between the diverter 8 and the outlet pipe 9 gradually decreases along the direction of airflow, and the inner diameter of the outlet pipe 9 is 3-5 mm.
[0044] After the primary ejector 1 and the secondary ejector 2, and the secondary ejector 2 and the tertiary ejector 3, are docked, the ejector tube 4, the primary mixing cavity, the secondary mixing cavity, and the tertiary mixing cavity are coaxially connected from left to right. In this embodiment, the primary ejector 1 and the secondary ejector 2 are connected by a threaded connection, while the secondary ejector 2 and the tertiary ejector 3 are connected by a flange connection, and sealing gaskets are provided at the connection points.
[0045] Furthermore, this embodiment also relates to a hydrogen fuel cell power system including the above-mentioned multi-stage ejector.
[0046] Example 2
[0047] The difference between this embodiment and embodiment 1 is that a pore network is provided in the first-stage mixing cavity of the multi-stage ejector, and the pore network is composed of a plurality of nickel alloy wires arranged in a staggered manner; the diameter of the nickel alloy wires is 0.1 to 0.9 mm, and the arrangement is random, and a plurality of protrusions are provided on the nickel alloy wires. The rest of the structure is the same as that of embodiment 1. Figure 4 This is a schematic diagram of the pore network structure described in this embodiment. This pore network significantly enhances gas turbulence, and the raised structures (not shown) on the nickel alloy wire further increase the irregularity of the gas flow, generating more turbulence and eddies. These turbulence and eddies ensure that the jet gas and the return gas fully contact and disperse in the primary mixing chamber, accelerating the mixing process and improving mixing efficiency.
[0048] The embodiments described are preferred implementations of the present invention, but the present invention is not limited to the above-mentioned implementations. Any obvious improvements, replacements or modifications that can be made by those skilled in the art without departing from the essential content of the present invention are within the scope of protection of the present invention.
Claims
1. A multi-stage ejector for a hydrogen fuel cell power system, characterized in that: It comprises a first-stage ejector (1), a second-stage ejector (2) and a third-stage ejector (3) connected in sequence along the airflow direction; The first-stage ejector (1) has a first-stage mixing inner cavity with one end open, and a jet tube (4) and a return tube (5) communicating with the first-stage mixing inner cavity are provided on the shell of the first-stage ejector (1); The secondary ejector (2) has a secondary mixing cavity with an opening at one end, and the left side of the secondary ejector (2) is docked with the right side of the primary ejector (1) and blocks the right opening of the primary mixing cavity; a capillary airflow channel (6) for connecting the primary mixing cavity and the secondary mixing cavity is provided on the shell of the secondary ejector (2) in contact with the primary mixing cavity; a plurality of mesh partitions (7) are provided in the secondary mixing cavity along the airflow direction, and the mesh partitions (7) divide the secondary mixing cavity into a plurality of small chambers; The three-stage ejector (3) has a three-stage mixing cavity with an open end, and the open end of the three-stage mixing cavity of the three-stage ejector (3) is connected to the secondary mixing cavity of the secondary ejector (2); a diverter (8) is provided in the three-stage mixing cavity, and an outlet pipe (9) for drawing out the mixed gas is provided on the shell of the three-stage ejector (3) on the right side of the three-stage mixing cavity; After the first-stage ejector (1) and the second-stage ejector (2), and the second-stage ejector (2) and the third-stage ejector (3) are docked, the jet tube (4), the first-stage mixing cavity, the second-stage mixing cavity, and the third-stage mixing cavity are in a coaxially connected state from left to right.
2. The multi-stage ejector according to claim 1, characterized in that: The shell of the secondary ejector (2) in contact with the primary mixing cavity has a first curved surface, a second curved surface and a third curved surface arranged coaxially; the first curved surface is trumpet-shaped, the outer diameter of the first curved surface is larger than its inner diameter, and diverges toward the side of the secondary mixing cavity; the second curved surface is trumpet-shaped, the outer diameter of the second curved surface is larger than its inner diameter, and diverges toward the side of the primary mixing cavity; the outer edge of the second curved surface is connected to the inner edge of the first curved surface; the third curved surface is a conical surface and faces the side of the primary mixing cavity, and the outer edge of the third curved surface is connected to the inner edge of the second curved surface; the capillary airflow channel (6) is a branched parallel pipe structure, having multiple air inlets and the same air outlet, and the multiple air inlets are evenly distributed circumferentially on the first curved surface and the third curved surface.
3. The multi-stage ejector according to claim 2, characterized in that: The cross section of the branch pipe of the capillary air flow channel (6) is circular, and its diameter is 10-20 mm; or the cross section of the branch pipe of the capillary air flow channel (6) is elliptical, and its major axis is 10-20 mm.
4. The multi-stage ejector according to claim 2, characterized in that: The branch pipe of the capillary airflow channel (6) is a spiral or wavy pipe structure, and the inner diameter of the pipe near the air outlet gradually decreases along the airflow direction.
5. The multi-stage ejector according to claim 1, characterized in that: The thickness of the mesh separator (7) is 0.1-0.5 mm, the spacing between adjacent mesh separators (7) is 1-5 mm, and the diameter of the micropores on the mesh separator (7) is 50-200 μm.
6. The multi-stage ejector according to claim 1, characterized in that: The mesh separator (7) is made of polytetrafluoroethylene or polyimide; the mesh separator (7) is provided with a hydrophobic coating having a thickness of 20 to 30 μm, and the material of the hydrophobic coating is polydimethylsiloxane.
7. The multi-stage ejector according to claim 1, characterized in that: The inner diameter of the three-stage mixing cavity between the flow splitter (8) and the air outlet pipe (9) gradually decreases along the air flow direction, and the inner diameter of the air outlet pipe (9) is 3-5 mm.
8. The multi-stage ejector according to claim 1, characterized in that: A pore network is provided in the primary mixing cavity, and the pore network is composed of a plurality of nickel alloy wires arranged in an interlaced manner; the diameter of the nickel alloy wire is 0.1-0.9 mm, and the arrangement manner is random arrangement or matrix arrangement, and a plurality of protrusions are provided on the nickel alloy wire.
9. The multi-stage ejector according to claim 1, characterized in that: The connection mode between the first-stage ejector (1) and the second-stage ejector (2) is threaded connection, and the connection mode between the second-stage ejector (2) and the third-stage ejector (3) is flange connection, and sealing gaskets are provided at the connection positions.
10. A hydrogen fuel cell power system, characterized in that: A multi-stage ejector comprising the multi-stage ejector according to any one of claims 1 to 9.