Porous ejector, use method thereof and fuel cell system

Abstract

The invention discloses a porous ejector, a use method thereof and a fuel cell system, and belongs to the technical field of fuel cells. Comprising a shell, a cavity is formed in the shell, and the cavity comprises a suction cavity, a mixing chamber, a second flow stabilizing chamber and a diffusion section which are sequentially arranged; a nozzle body is mounted in the suction cavity and is used for accelerating and depressurizing the driving fluid and spraying the accelerated and depressurized driving fluid into the suction cavity to form a negative pressure area; an ejection opening is formed in the side wall, corresponding to the suction cavity, of the shell and used for introducing an ejection fluid, and the ejection fluid and the driving fluid subjected to acceleration and pressure reduction are mixed in the mixing chamber; a nozzle assembly is arranged at the end, close to the mixing chamber, of the nozzle body and comprises at least one nozzle, and driving fluid is accelerated through a hole channel of the nozzle. The invention provides a porous ejector, a use method thereof and a fuel cell system, and solves the technical problems of low fuel injection efficiency and insufficient energy utilization of a single-hole ejector used in a traditional hydrogen supply system.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and more specifically, to a porous ejector, its usage method, and a fuel cell system. Background Art

[0002] A fuel cell hydrogen supply system is a key energy conversion device that generates electrical energy by reacting hydrogen with oxygen. However, in traditional hydrogen supply systems, there are some problems with fuel injection technology. Conventional ejectors cannot achieve refined and uniform fuel injection, resulting in low fuel mixing efficiency and insufficient energy utilization.

[0003] Specifically, an ejector is a fluid device that accelerates a driving fluid (such as hydrogen) to a high speed to form a low-pressure zone, attracts and mixes the driving fluid with an inhaled fluid, and converts kinetic energy into pressure energy during the diffusion process to transport the mixed fluid. In a fuel cell, hydrogen is the main fuel source, and its efficient and uniform distribution is a key factor in battery performance.

[0004] However, existing single-hole ejectors cannot meet such requirements, and they have obvious limitations in fuel mixing, flow control, and fuel cell efficiency: 1. Fuel mixing: Single-hole ejectors cannot achieve sufficient mixing of fuel gas and hydrogen. This is because when the fluid flows out of a single orifice, it is prone to form an air flow beam rather than extensive diffusion, which leads to uneven fuel mixing and affects the energy conversion efficiency.

[0005] 2. Flow control: Conventional single-hole ejectors operate under a fixed gas supply pressure. They usually cannot meet the full range of operating conditions of fuel cells from low load (such as standard air cooling) to high load (such as full electric load). This means that in high-flow operating conditions, it is necessary to increase the hydrogen pump or use two ejectors.

[0006] 3. Fuel cell efficiency: Due to the above reasons, the overall efficiency of the fuel cell is affected. Uneven hydrogen distribution may cause higher reaction activity in some parts of the fuel cell stack, which in turn forms non-uniformities in pressure recovery, gas flow dynamics distribution, and temperature distribution. This may reduce the average efficiency of the system and increase component wear and degradation.

[0007] In summary, traditional ejector nozzles usually consist of a single injection hole. By using the pressure difference, the entrained fluid is inhaled, remixed with the supplied hydrogen, and then resupplied to the fuel cell stack to ensure sufficient flow. Traditional single-hole ejectors usually consist of a nozzle, a mixing chamber, and a diffuser chamber. The fuel forms a high-speed and low-pressure area through the nozzle, inhales the entrained fluid through the pressure difference for mixing, and then resupplies it to the fuel cell stack through the diffuser chamber. However, the traditional ejector design has certain limitations and cannot achieve uniform mixing and efficient transportation of hydrogen and fuel, resulting in low injection efficiency. During the operation of traditional single-hole ejectors, when the large-angle jet flow generated by a single nozzle mixes with the entrained fluid, significant energy losses will occur, which will affect the performance and efficiency of fuel cells. In addition, single-hole ejectors cannot cover the entire range from the idle point to the large-flow condition, and it is necessary to increase the hydrogen pump or use two ejectors. Therefore, single-hole ejectors have technical problems and defects such as low injection efficiency, uneven fuel mixing, and insufficient energy utilization in fuel cell systems.

[0008] Therefore, a new type of efficient multi-hole ejector is needed to solve these problems and improve the performance and efficiency of fuel cell systems. Summary of the Invention

[0009] The present invention provides a multi-hole ejector, a method for using the same, and a fuel cell system to overcome the technical problems of low fuel injection efficiency and insufficient energy utilization existing in the use of single-hole ejectors in traditional hydrogen supply systems.

[0010] To solve the above technical problems, the technical solutions of the present invention are as follows: According to the first aspect of the present invention, the present invention provides a multi-hole ejector, including a housing. A cavity is provided inside the housing, and the cavity includes an inhalation chamber, a mixing chamber, a second steady flow chamber, and a diffuser section arranged in sequence; A nozzle body is installed in the inhalation chamber. The nozzle body is used to accelerate and depressurize the driving fluid, and inject the accelerated and depressurized driving fluid into the inhalation chamber to form a negative pressure area; An ejection port is provided on the side wall of the housing corresponding to the inhalation chamber. The ejection port is used to introduce the entrained fluid, and the entrained fluid is mixed with the accelerated and depressurized driving fluid in the mixing chamber; The second steady flow chamber is used to enable the entrained fluid to be fully mixed with the accelerated and depressurized driving fluid, and transfer the kinetic energy of the accelerated and depressurized driving fluid to the entrained fluid during the mixing process, thereby driving the entrained fluid to accelerate; The diffuser section is used to receive the mixed gas of the driving fluid and the entrained fluid that has been steady-flowed in the second steady flow chamber, and discharge the mixed gas; One end of the nozzle body close to the mixing chamber is provided with a nozzle assembly, the nozzle assembly includes at least one nozzle, and the driving fluid is accelerated through the channel of the nozzle.

[0011] Furthermore, one end of the nozzle body away from the mixing chamber is provided with a jet port for inputting the driving fluid. The nozzle body is provided with a first steady flow chamber for the driving fluid to pass through between the jet port and the nozzle, which is used to stabilize the flow of the driving fluid.

[0012] Furthermore, the flow area of the nozzle on the nozzle assembly is smaller than that of the first steady flow chamber.

[0013] Furthermore, both the first steady flow chamber and the second steady flow chamber are cylindrical channels with a constant flow area.

[0014] Furthermore, one end of the mixing chamber for inputting the driving fluid and the entrained fluid is the first input end, the other end of the mixing chamber is the first output end, and the flow area of the mixing chamber gradually decreases from the first input end to the first output end.

[0015] Furthermore, one end of the diffuser section for inputting the mixed gas of the driving fluid and the entrained fluid is the second input end, the other end of the diffuser section is the second output end, and the flow area of the diffuser section gradually increases from the second input end to the second output end.

[0016] Furthermore, the number of the nozzles is 2 - 16.

[0017] Furthermore, the driving fluid is hydrogen.

[0018] According to the second aspect of the present invention, the present invention provides a method for using a porous ejector. Based on the foregoing porous ejector, the method for using includes the following steps: The driving fluid is introduced through the jet port, and the entrained fluid is introduced through the entrainment port. The driving fluid is accelerated and depressurized through the nozzle body and then preliminarily mixed with the entrained fluid in the mixing chamber. After the driving fluid and the entrained fluid are preliminarily mixed in the mixing chamber, they are input into the second steady flow chamber, and the kinetic energy of the driving fluid is transferred to the entrained fluid during the mixing process, thereby driving the entrained fluid to accelerate. The mixed gas of the driving fluid and the entrained fluid enters the diffuser section after being stabilized by the second steady flow chamber and is discharged through the diffuser section.

[0019] According to the third aspect of the present invention, the present invention provides a fuel cell system, and the foregoing porous ejector is installed in the fuel cell system.

[0020] Compared with the prior art, the beneficial effects of the technical solution of the present invention are as follows: 1. Uniform and high-speed flow: The porous ejector has multiple nozzles, and hydrogen can form a uniform high-speed flow in the mixing chamber through these orifices; 2. Operational flexibility: By changing the number and shape of the nozzle groups, the fluid flow rate can be adjusted according to different requirements of the entrainment ratio; 3. Advantages of structural design: Its design reduces the gas flow resistance and can uniformly inject hydrogen into the mixing area through small holes, improving the mixing effect and efficiency; 4. Improving the performance of fuel cells: Due to the uniform mixing of hydrogen and fuel, the performance and stability of fuel cells can be effectively improved; 5. Improving fluid distribution: Through multiple small holes, the overall hydrodynamic distribution is improved, reducing the dead zone effect and enhancing the mixing effect; 6. Enhancing the mixing effect: The high Mach number ejection of the small-hole nozzles can increase the kinetic energy and promote the mutual diffusion and mixing of fluids; 7. Expanding the mixing area: The diameter of the mixing chamber is increased, increasing the mixing area of the mixed gas and enhancing the entrainment effect; 8. Achieving efficient entrainment: By generating large turbulence through high-speed injection, the entrainment effect is enhanced, and the area of the low-pressure region is increased to suck in more secondary fluid; 9. Wide applicability: The design of the porous ejector can be optimized according to actual needs and is applicable to different types and specifications of fuel cells.

[0021] Generally speaking, this porous ejector has the advantages of strong flexibility, high use efficiency, and reducing flow resistance, etc., and can effectively solve the problems existing in the traditional single-hole ejector, improving the performance and stability of fuel cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0023] Figure 1 is a schematic structural diagram of the porous ejector of the present invention; Figure 2 is a schematic structural diagram of the nozzle body in the porous ejector of the present invention; Figure 3 is a schematic diagram of the nozzle assembly, and the nozzle assembly in this figure is provided with three nozzles; Figure 4 Another schematic diagram of the nozzle assembly, in which the nozzle assembly is provided with seven nozzles; Figure 5 Schematic diagram of the experimental test bench; Figure 6 Performance MPA curve diagram of the porous ejector of the present invention; Wherein, A1 is the entrainment ratio of the porous ejector under a pressure difference of 2 kPa, A2 is the entrainment ratio of the porous ejector under a pressure difference of 4 kPa, A3 is the entrainment ratio of the porous ejector under a pressure difference of 6 kPa, A4 is the entrainment ratio of the porous ejector under a pressure difference of 10 kPa, and A5 is the entrainment ratio of the porous ejector under a pressure difference of 15 kPa; B1 is the pressure at the working fluid inlet under a pressure difference of 2 kPa, B2 is the pressure at the working fluid inlet under a pressure difference of 4 kPa, B3 is the pressure at the working fluid inlet under a pressure difference of 6 kPa, B4 is the pressure at the working fluid inlet under a pressure difference of 10 kPa, and B5 is the pressure at the working fluid inlet under a pressure difference of 15 kPa; Figure 7 Performance comparison curve diagram of the porous ejector of the present invention and the existing single-hole ejector; Wherein, A1 is the entrainment ratio of the porous ejector under a pressure difference of 2 kPa, and A5 is the entrainment ratio of the porous ejector under a pressure difference of 15 kPa; B1 is the pressure at the working fluid inlet under a pressure difference of 2 kPa, and B5 is the pressure at the working fluid inlet under a pressure difference of 15 kPa; C1 is the entrainment ratio of the single-hole ejector under a pressure difference of 2 kPa, and C5 is the entrainment ratio of the single-hole ejector under a pressure difference of 15 kPa; Explanation of the markings in the figure: 1. Entrainment port; 2. Jet port; 3. First steady flow chamber; 4. Nozzle; 5. Mixing chamber; 6. Second steady flow chamber; 7. Diffuser section; 8. Suction chamber. Detailed implementation manners

[0024] In order to better understand the purpose, structure and function of the present invention, the technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific preferred embodiments.

[0025] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by terms such as "left side", "right side", "upper part", "lower part", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. "First", "second", etc. do not represent the importance of the components, so they should not be construed as limitations on the present invention. The specific dimensions adopted in the embodiments are only for illustrating the technical solutions by way of example, and do not limit the protection scope of the present invention. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0026] Unless otherwise clearly specified and defined, terms such as "installation", "setting", "connection", "fixation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0027] Embodiment 1:

[0028] As Figure 1 shown, the present invention provides a technical solution: a porous ejector, including a housing, a cavity is provided inside the housing, and the cavity includes a suction chamber 8, a mixing chamber 5, a second steady flow chamber 6 and a diffuser section 7 arranged in sequence; A nozzle body is installed in the suction chamber 8, and the nozzle body is a porous parallel nozzle body; The nozzle body is used to accelerate and depressurize the driving fluid, and inject the accelerated and depressurized driving fluid into the suction chamber 8 to form a negative pressure area; An ejection port 1 is provided on the side wall of the housing corresponding to the suction chamber 8, and the ejection port 1 is used to introduce the ejection fluid, and the ejection fluid is mixed with the accelerated and depressurized driving fluid in the mixing chamber 5; The second steady flow chamber 6 is used to fully mix the ejection fluid with the accelerated and depressurized driving fluid, and transfer the kinetic energy of the accelerated and depressurized driving fluid to the ejection fluid during the mixing process, so as to push the ejection fluid to accelerate; The diffuser section 7 is used to receive the mixed gas of the driving fluid and the ejection fluid that has been steady-flowed from the second steady flow chamber 6, and discharge the mixed gas; A nozzle assembly is provided at one end of the nozzle body close to the mixing chamber 5, and the nozzle assembly includes at least one nozzle 4, and the driving fluid is accelerated through the orifice of the nozzle 4; Multiple small holes of the porous nozzle can make hydrogen jet out of the nozzle more uniformly. In this way, the situation of fluid flow dead zones in certain areas can be avoided, thereby improving the mixing effect.

[0029] Furthermore, a porous nozzle assembly is provided at one end of the porous parallel nozzle body close to the mixing chamber. The nozzle assembly includes at least two nozzles 4, and the driving fluid is accelerated through a constricted flow channel. The porous parallel structure enables the driving fluid to generate multiple uniform sprays after passing through the nozzle body, thereby improving the entrainment efficiency.

[0030] In addition, multiple high-speed and directional fluid jets generated by the porous parallel structure nozzle increase the working area and entrainment capacity of the ejector, thereby improving the entrainment efficiency. Increase the working area and entrainment capacity of the ejector, thereby improving the entrainment efficiency. Shorten the length of the mixing chamber, thereby reducing the size of the ejector.

[0031] Furthermore, the design of the porous nozzle can reduce the nozzle size and meet the design requirements by changing the number of nozzles 4. The smaller diameter enables the fluid to jet out at a higher Mach number, thereby increasing the kinetic energy of the fluid; this increase in kinetic energy can promote the mutual diffusion and mixing between fluids and improve the mixing effect.

[0032] Specifically, the design of the porous nozzle can increase the diameter of the suction chamber and improve the disadvantage of the small diameter of the suction chamber of the single-hole ejector; the enlarged diameter of the suction chamber can increase the mixing area of the hydrogen and secondary flow mixed gas in the diffusion chamber, thereby enhancing the entrainment effect.

[0033] Moreover, the design of the porous nozzle can make the fluid jet out at high speed through multiple small holes, generating a flow state with high turbulence intensity, generating a greater flow velocity, increasing the mixed low-pressure area, and thus sucking in more secondary fluid.

[0034] In this embodiment, the porous ejector injects hydrogen into the mixing chamber 5 through a microporous structure, generates high-speed fluid, forms a negative pressure area, and sucks in more mixed fluid, thereby enhancing the entrainment efficiency of the ejector under large flow rates. Such a porous ejector is designed with a highly permeable structure, which can effectively reduce the fluid flow resistance. Driven by a high-pressure hydrogen source, hydrogen enters through the air inlet of the porous ejector and enters the mixing area through uniformly distributed micropores, realizing the uniform mixing of hydrogen and fuel. This mixing method can reduce the dead zone effect, improve the entrainment efficiency, and thus improve the performance and stability of the fuel cell; at the same time, it can effectively reduce the lengths of the mixing section and the flow stabilization chamber and reduce the size of the ejector.

[0035] Embodiment 2:

[0036] Based on Embodiment 1, referring to Figure 1-4, a jet port 2 is provided at one end of the nozzle body away from the mixing chamber 5, and the jet port 2 is used to input the driving fluid; A first steady flow chamber 3 for the driving fluid to pass through is provided between the jet port 2 and the nozzle 4 of the nozzle body, for stabilizing the flow of the driving fluid.

[0037] In the porous ejector of the present invention, high-pressure fluid is introduced through the jet port 2, passes through the first steady flow chamber 3, and uniform high-speed and low-pressure fluid is generated by a plurality of nozzle-shaped nozzles 4, and is mixed with the secondary fluid sucked in through the mixing chamber 5 and the ejector port 1, and then comes to the diffuser section 7 through the second steady flow chamber 6, and finally outputs the mixed fluid.

[0038] Further, the flow area of the nozzle 4 on the nozzle assembly is smaller than the flow area of the first steady flow chamber 3.

[0039] Further, both the first steady flow chamber 3 and the second steady flow chamber 6 are cylindrical channels with a constant flow area.

[0040] Further, one end of the mixing chamber 5 for inputting the driving fluid and the ejecting fluid is the first input end, the other end of the mixing chamber 5 is the first output end, and the flow area of the mixing chamber 5 gradually decreases from the first input end to the first output end.

[0041] Further, one end of the diffuser section 7 for inputting the mixed gas of the driving fluid and the ejecting fluid is the second input end, the other end of the diffuser section 7 is the second output end, and the flow area of the diffuser section 7 gradually increases from the second input end to the second output end.

[0042] Further, the number of the nozzles 4 is 2 - 16; More preferably, the number of the nozzles 4 is 2 - 9; for the porous nozzle, the nozzle style can be changed according to different working conditions requirements, such as changing the number of holes, hole diameter, nozzle length and arrangement method to cover the full working conditions requirements.

[0043] Further, the driving fluid is hydrogen.

[0044] Further, the structural parameters of the porous ejector can be optimized according to actual needs to meet the requirements of different types and specifications of fuel cells.

[0045] The working principle of the porous ejector in this embodiment is as follows: The gas passes through the jet port 2 and then generates a stable flow through the steady flow channel, and then passes through the small-sized porous nozzle, so that the fluid velocity increases and high-Mach-number fluid is generated. At the same time, a negative pressure region is generated in the mixing chamber 5. Due to the existence of the low-pressure region, the suction chamber sucks back the secondary fluid and mixes it with the hydrogen at the front end. The mixed fluid then enters the diffuser section 7 of the Venturi tube and then enters the fuel cell stack.

[0046] During the working process, due to the porous injection, the gas rapidly increases its flow velocity through multiple nozzles 4, generating a high Mach number fluid. For different injection ratio requirements, by changing the number and shape of the nozzles, the flow velocity is increased or decreased to achieve the target injection requirements. Currently, according to the working conditions, the number of nozzles can be adjusted to 2 - 16, which are specially distributed at specific positions, and the nozzle aperture can be changed according to the injection requirements. After being accelerated by the porous nozzles, the negative pressure area in front of the nozzle 4 increases, and the secondary fluid is sucked into the ejector and goes to the fuel cell stack through the section 7 to be diffused and pressurized.

[0047] In summary, the porous ejector of this embodiment introduces high-pressure fluid through the jet orifice 2, generates a uniform high-speed and low-pressure fluid by the nozzle 4 after passing through the first steady flow chamber 3, mixes with the secondary fluid sucked in through the injection port 1 in the mixing chamber 5, then comes to the diffuser section 7 through the second steady flow chamber 6, and finally outputs the mixed fluid.

[0048] Embodiment 3:

[0049] The present invention provides a technical solution: a method for using a porous ejector. Based on the aforementioned porous ejector, the method for use includes the following steps: Introduce the driving fluid through the jet orifice 2 and introduce the injected fluid through the injection port 1; The driving fluid is accelerated and depressurized by the nozzle body and then preliminarily mixed with the injected fluid in the mixing chamber 5; After the driving fluid and the injected fluid are preliminarily mixed in the mixing chamber 5, they are input into the second steady flow chamber 6. During the mixing process, the kinetic energy of the driving fluid is transferred to the injected fluid, and the injected fluid obtains the kinetic energy transferred by the working fluid, thereby promoting the acceleration of the injected fluid; The mixed gas of the driving fluid and the injected fluid enters the diffuser section 7 after being stabilized by the second steady flow chamber 6 and is discharged through the diffuser section 7.

[0050] Embodiment 4:

[0051] The present invention provides a technical solution: a fuel cell system, in which the aforementioned porous ejector is installed.

[0052] Proof of beneficial effects: Take the working fluid inlet, the injected fluid inlet and the mixed fluid outlet of the porous ejector as the test connection points and connect them to the test bench. The pipe diameter of the connection between the bench and the ejector is equal to the pipe diameters of the inlet and outlet of the ejector itself.

[0053] For the static pressure measurement at the inlet and outlet of the ejector, a circular-section measuring tube with a straight and smooth inner wall is used. The pipe area is larger than the connected inlet and outlet areas. According to the pressure measurement regulations in 4.3 of GB / T 23341.2-2018, the pipe length is not less than 5 times the pipe diameter, and the straight section length (in the direction of the air flow) before the static pressure measurement point is not less than 2 times the pipe diameter. The accuracy of the pressure sensor meets the requirements specified in Table 1, and the layout position is as shown in Figure 5 shown.

[0054] Test environment: The test temperature is 30 °C, and the test high-pressure gas is compressed air; the test is carried out under the environment of normal atmospheric pressure, ensuring natural ventilation and no air pollution.

[0055] Table 1. Main measuring devices and accuracies:

[0056] Test steps: Select the corresponding pressure difference value within the working pressure difference range of the ejector according to the technical requirements of the ejector. Adjust the pressure of the pressure sensor 2 to a reference value through the pressure regulator at the inlet of the ejector fluid. Adjust the outlet pressure of the ejector and the working fluid flow rate of the ejector for testing. Wait until the displayed values of pressure, flow rate, etc. in the test data are stable, and record the relevant data of flow rate and pressure. Calculate according to the ejector ratio formula, conduct a series of measurements under different pressure differences and flow rates, calculate the ejector ratio, and obtain the MAP diagram of the ejector pressure difference, flow rate, ejector ratio, and working fluid inlet pressure.

[0057] Ejector ratio: The ratio of the mass flow rate me of the low-pressure ejector fluid to the mass flow rate mw of the high-pressure working fluid, dimensionless, represented by the symbol ω.

[0058] ω = me / mw The specific test method for the multi-hole ejector is as follows: 1. Connect the ejector to be tested when the pipeline gas source is confirmed to be closed and there is no pressure inside the pipeline; 2. Open the high-pressure gas source and observe the high-pressure sensors 1 and 3, and adjust the pressure regulating valves 1 and 2 to control the pressure at the specified value; 3. Start the multi-hole ejector, conduct tests according to different pressure differences and working pressures, adjust the outlet pressure regulating valve 3 of the ejector, and make the back pressure reach the target pressure value and target pressure difference of the pressure sensor 3. After the pressure and flow rate are stable, record the measured flow rate values of the flow rate sensors 1 and 2 and the pressure values of the pressure sensors 2 and 3; 4. Repeat step 3 until all the measured pressure differences to be tested are completed under the set working fluid inlet flow rate; 5. During testing, the value at each test point should be measured after the control parameters are adjusted to the specified values and have been stable for 3 minutes. Each point should be measured 5 times, and the average value should be taken for calculation. 6. After the test is completed, first close the gas source, and set the back pressure valve controller and the flow controller to fully open to relieve the pressure in the pipeline. Test results: The test results of the performance of the multi-hole ejector are as Figure 6 shown. Δp represents the pressure difference of the ejector, which is the difference between the outlet pressure and the inlet pressure of the ejector fluid, and the unit is kPa. It can be seen that at a pressure difference of 2 kPa, the entrainment ratio first increases and then decreases with the increase of the flow rate. The maximum entrainment ratio reaches 2.04, and the minimum entrainment ratio is 1.82. Similarly, with the continuous increase of the pressure difference, the entrainment ratio gradually decreases. At a pressure difference of 15 kPa, the maximum entrainment ratio is 1.15, and the minimum entrainment ratio is 0.96.

[0059] The comparison between the multi-hole ejector and the original single-hole ejector design is as Figure 7 shown. It can be seen that at a pressure difference of 2 kPa, at low flow rates, the difference in the entrainment ratio between the multi-hole ejector and the single-hole ejector is not significant. However, with the increase of the flow rate, the entrainment ratio of the multi-hole ejector is higher than that of the single-hole ejector. At 600 slpm, the entrainment ratio of the multi-hole ejector is 0.28 higher than that of the single-hole ejector. In addition, with the increase of the pressure difference, the entrainment ratio of the multi-hole ejector scheme is also significantly better than that of the single-hole ejector. It can be seen that at high flow rates, the multi-hole ejector can solve the problems of low fuel injection efficiency and insufficient energy utilization caused by using a single-hole ejector in the traditional hydrogen supply system.

[0060] Obviously, the above-mentioned embodiments of the present invention are merely examples for clearly explaining the present invention, rather than limiting the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A porous ejector, characterized in that: It comprises a shell, wherein a cavity is provided inside the shell, and the cavity comprises a suction chamber (8), a mixing chamber (5), a second flow stabilization chamber (6) and a diffuser section (7) which are arranged in sequence; A nozzle body is installed in the suction chamber (8), and the nozzle body is used to accelerate and reduce the pressure of the driving fluid, and spray the accelerated and reduced-pressure driving fluid into the suction chamber (8) to form a negative pressure area; The side wall of the shell corresponding to the suction chamber (8) is provided with an injection port (1), the injection port (1) being used to introduce an injection fluid, the injection fluid being mixed with the driving fluid after accelerated decompression in the mixing chamber (5); The second stabilizing chamber (6) is used to fully mix the ejection fluid with the accelerated and depressurized driving fluid, and during the mixing process, the kinetic energy of the accelerated and depressurized driving fluid is transferred to the ejection fluid, thereby accelerating the ejection fluid; The diffuser section (7) is used to receive a mixed gas of the driving fluid and the ejection fluid after flow stabilization from the second flow stabilization chamber (6), and discharge the mixed gas; A nozzle assembly is provided at one end of the nozzle body close to the mixing chamber (5), the nozzle assembly comprising at least one nozzle (4), and the driving fluid is accelerated through the channel of the nozzle (4).

2. The multi-hole ejector according to claim 1, characterized in that: An end of the nozzle body away from the mixing chamber (5) is provided with a jet port (2), and the jet port (2) is used to input the driving fluid; The nozzle body is provided with a first stabilizing chamber (3) between the jet port (2) and the nozzle (4) for the driving fluid to pass through, and is used to stabilize the flow of the driving fluid.

3. The multi-hole ejector according to claim 2, characterized in that: The flow area of ​​the nozzle (4) on the nozzle assembly is smaller than the flow area of ​​the first stabilizing chamber (3).

4. The multi-hole ejector according to claim 2, characterized in that: The first stabilizing flow chamber (3) and the second stabilizing flow chamber (6) are both cylindrical channels with a constant flow area.

5. The multi-hole ejector according to claim 1, characterized in that: One end of the mixing chamber (5) for inputting the driving fluid and the ejecting fluid is a first input end, and the other end of the mixing chamber (5) is a first output end. The flow area of ​​the mixing chamber (5) gradually decreases from the first input end to the first output end.

6. The multi-hole ejector according to claim 1, characterized in that: One end of the diffuser section (7) for inputting a mixed gas of the driving fluid and the ejecting fluid is a second input end, and the other end of the diffuser section (7) is a second output end. The flow area of ​​the diffuser section (7) gradually increases from the second input end to the second output end.

7. The multi-hole ejector according to claim 1, characterized in that: The number of the nozzles (4) is 2-16.

8. The multi-hole ejector according to claim 1, characterized in that: The driving fluid is hydrogen.

9. A method for using a porous ejector, based on the porous ejector according to any one of claims 1 to 8, characterized in that: The method of use comprises the following steps: A driving fluid is introduced through the jet port (2), and an injection fluid is introduced through the injection port (1); The driving fluid is accelerated and depressurized through the nozzle body and then preliminarily mixed with the ejecting fluid in the mixing chamber (5); After the driving fluid and the ejection fluid are preliminarily mixed in the mixing chamber (5), they are input into the second stabilizing chamber (6), and during the mixing process, the kinetic energy of the driving fluid is transferred to the ejection fluid, thereby accelerating the ejection fluid; The mixed gas of the driving fluid and the ejecting fluid enters the diffuser section (7) after being stabilized by the second flow stabilization chamber (6), and is discharged through the diffuser section (7).

10. A fuel cell system, characterized in that: The fuel cell system is equipped with the porous ejector according to any one of claims 1 to 8.

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