An ejector and a test system thereof

Abstract

The application belongs to the technical field of fuel cells, and particularly relates to an ejector and a test system thereof. At present, the test system and method of the ejector of the fuel cell system are difficult to effectively monitor the two-phase flow distribution characteristics in the ejector. The application provides an ejector, which comprises a first visual component, an ejector body and a second visual component connected in sequence, the ejector body is connected with a primary flow nozzle, a flow channel is arranged in the ejector body, the flow channel is composed of a plurality of planes, and a primary flow inlet, a secondary flow inlet and an outlet are arranged on the ejector body. The two-phase flow characteristics in the transparent flow channel of the ejector are accurately evaluated by using a visual measurement method.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of fuel cells, and particularly relates to an ejector and a test system thereof. BACKGROUND

[0002] A hydrogen fuel cell is a device for generating electric energy through an electrochemical reaction of hydrogen and oxygen, has the advantages of high efficiency and power density, zero emission, and silent operation, and is one of the key technologies of new energy in the future. A fuel cell system is composed of a hydrogen supply subsystem, an oxygen supply subsystem, a thermal management system, and the like. The hydrogen circulation ejector is one of the key components of the hydrogen circulation system. The working principle of the ejector is to use the Venturi effect generated by the high-speed primary flow to pressurize and inject the circulation tail gas (i.e., the secondary flow). The primary flow of the ejector is high-purity hydrogen from a high-pressure hydrogen cylinder. The secondary flow of the ejector is a two-phase multi-component mixture containing hydrogen, water vapor, nitrogen, and liquid water. The ejector performance affects the efficiency and service life of the fuel cell. In order to ensure that the performance of the ejector fully meets the normal working requirements of the fuel cell, the performance of the ejector needs to be tested. The conventional test system for the ejector of the fuel cell system mainly monitors the macroscopic physical quantities of the ejector, i.e., the flow and pressure variation characteristics, and does not involve local microscopic flow characteristics.

[0003] Because the secondary flow of the ejector of the fuel cell system contains liquid water droplets, the movement and distribution of the liquid droplets in the secondary flow in the ejector will have a certain influence on the ejector performance. At the same time, the water vapor contained in the high-temperature secondary flow of the ejector will condense when mixed with the low-temperature primary flow, and the condensation process and the generated liquid droplets will also affect the ejector performance. Therefore, in order to monitor the performance characteristics of the ejector in the fuel cell system, the two-phase flow distribution characteristics of the liquid droplets in the ejector also need to be tested. SUMMARY

[0004] 1. Technical problem to be solved

[0005] Based on the conventional ejector test system, only the macroscopic physical quantities of the ejector are concerned, including the flow and pressure variation, but in the actual fuel cell system, the movement characteristics of the liquid droplets in the secondary flow of the ejector may affect the ejector performance, and the mixing of the low-temperature primary flow and the high-temperature secondary flow causes the condensation of water vapor in the secondary flow, which further affects the distribution of the liquid droplets. The current test system and method for the ejector of the fuel cell system cannot effectively monitor the two-phase flow distribution characteristics in the ejector, and the application provides an ejector and a test system thereof.

[0006] 2. Technical solution

[0007] In order to achieve the above-mentioned purpose, the application provides an ejector, which comprises a first visible component, an ejector body and a second visible component connected in sequence, the ejector body is connected with a primary flow nozzle, a flow channel is arranged in the ejector body, the flow channel is composed of a plurality of planes, and a primary flow inlet, a secondary flow inlet and an outlet are arranged on the ejector body.

[0008] Another embodiment provided by the application is that the first visible component comprises a first cover plate and a first perspective window, the second visible component comprises a second perspective window and a second cover plate, and the first cover plate, the first perspective window, the ejector body, the second perspective window and the second cover plate are connected in sequence.

[0009] Another embodiment provided by the application is that the ejector body is provided with a first groove and a second groove, the first cover plate fixes the first perspective window on the ejector body through the first groove, and the second cover plate fixes the second perspective window on the ejector body through the second groove.

[0010] Another embodiment provided by the application is that the first cover plate comprises a hollow structure, and the second cover plate comprises a hollow structure.

[0011] Another embodiment provided by the application is that the ejector body is a cuboid structure, and the ejector body is made of transparent material.

[0012] The application further provides a test system for the ejector, which comprises a primary flow component, a first flow controller, the ejector and a mixed flow component connected in sequence, a temperature sensor and a first pressure sensor are arranged between the first flow controller and the ejector, a second pressure sensor and a first temperature and humidity sensor are arranged between the ejector and the mixed flow component, the ejector is connected with a secondary flow component, a third pressure sensor and a second temperature and humidity sensor are arranged between the ejector and the secondary flow component, a flow control group is arranged on the secondary flow component, the temperature sensor, the first pressure sensor, the second pressure sensor, the first temperature and humidity sensor, the third pressure sensor and the second temperature and humidity sensor are connected with a signal acquisition and processing module respectively, a light source emitting end is arranged on one side of the ejector, and a light source receiving end is arranged on the other side of the ejector.

[0013] Another embodiment provided by the application is that the primary flow component comprises a high-pressure hydrogen cylinder, the high-pressure hydrogen cylinder, a first pressure reducing valve and the first flow controller are connected in sequence.

[0014] Another embodiment provided in the application is that the mixed flow assembly comprises a pressure regulating cavity, the ejector, the pressure regulating cavity and the tail gas recovery tank are sequentially connected, and the second pressure sensor and the first temperature and humidity sensor are arranged between the ejector and the pressure regulating cavity.

[0015] Another embodiment provided in the application is that the flow control group comprises a second flow controller and a third flow controller, the secondary flow assembly comprises a hydrogen assembly and a nitrogen assembly connected with each other, the hydrogen assembly comprises a hydrogen cylinder, a second pressure reducing valve, the second flow controller, a first heating humidifier and a gas-liquid mixer connected in sequence, the nitrogen assembly comprises a nitrogen cylinder, a third pressure reducing valve, the third flow controller, a second heating humidifier, a first needle valve and the gas-liquid mixer connected in sequence, the second heating humidifier, the second needle valve and an atomization assembly are connected with the gas-liquid mixer, the gas-liquid mixer is connected with the ejector, and the third pressure sensor and the second temperature and humidity sensor are arranged between the gas-liquid mixer and the ejector.

[0016] Another embodiment provided in the application is that the atomization assembly comprises a liquid droplet atomization nozzle and a water tank connected with each other, and the second needle valve, the liquid droplet atomization nozzle and the gas-liquid mixer are sequentially connected.

[0017] 3. Beneficial effects

[0018] Compared with the prior art, the beneficial effects of the ejector and the test system thereof provided in the application are that:

[0019] The ejector and the test system thereof provided in the application solve the problem that the conventional test method of the fuel cell system ejector is difficult to comprehensively test the performance of the ejector.

[0020] The ejector provided in the application is a visualized ejector for a fuel cell system, which can accurately test the conventional performance and two-phase flow characteristics of the ejector and monitor the macroscopic performance and local flow characteristics of the ejector in the fuel cell system.

[0021] The ejector provided in the application is composed of a plurality of detachable components, and has a simple structure and is easy to process.

[0022] The test system of the ejector provided in the application can not only accurately test the change of the macroscopic physical quantity of the ejector, but also monitor the local flow characteristics of the ejector in the fuel cell system. The system can comprehensively test the characteristics of the fuel cell system ejector in all directions, can perfect the design and application of the ejector, and guarantee the stable and efficient operation of the stack.

[0023] The ejector test system provided by the application uses a visual measurement method to accurately evaluate the two-phase flow characteristics in the transparent flow channel of the ejector. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a schematic diagram of an existing ejector structure;

[0025] Figure 2 is a schematic diagram of an ejector structure of the application;

[0026] Figure 3 is a schematic diagram of an ejector body of the application;

[0027] Figure 4 is a schematic diagram of an ejector test system of the application;

[0028] Figure 5 is a schematic diagram of macroscopic performance changes of the ejector of the application;

[0029] Figure 6 is a schematic diagram of visualized flow characteristics of the ejector of the application. DETAILED DESCRIPTION

[0030] In the following, specific embodiments of the application will be described in detail with reference to the accompanying drawings, on the basis of which those skilled in the art will be able to clearly understand the application and to implement it. The features of the various different embodiments can be combined to obtain new embodiments, or to replace certain features in certain embodiments, without departing from the principles of the application.

[0031] Referring to Figures 1-6 , the application provides an ejector 2 comprising a first visual assembly, an ejector body 3 and a second visual assembly connected in sequence, the ejector body 3 being connected with a primary flow nozzle 8, the ejector body 3 being provided with a flow channel 65, the flow channel 65 being composed of a plurality of planes, the ejector body 3 being provided with a primary flow inlet 61, a secondary flow inlet 62 and an outlet 63.

[0032] The ejector 2 is designed as a plane flow channel structure, and the visual assemblies are provided on both sides to ensure that the light is not refracted by the curved surface. The internal flow channel 65 of the ejector body 3 is composed of planes, which can ensure that the straight light entering during the visual experiment test is not affected, thereby causing errors in the measurement image. The body of a conventional ejector is a cylindrical curved surface, and when the parallel light during the visual experiment measurement enters the ejector, the curved surface of the ejector 2 will refract the light, thereby affecting the light intensity information of the light passing through the ejector 2, and finally causing the optical signal collected to deviate, resulting in incorrect measurement results.

[0033] The components in the ejector 2 of the application can be disassembled.

[0034] Further, the first visual component comprises a first cover plate 6 and a first transparent window 4, and the second visual component comprises a second transparent window 5 and a second cover plate 7, and the first cover plate, the first transparent window, the ejector body, the second transparent window and the second cover plate are sequentially connected.

[0035] Further, the ejector body 3 is provided with a first groove 66 and a second groove, the first cover plate 6 fixes the first transparent window 4 on the ejector body 3 through the first groove 66, and the second cover plate 7 fixes the second transparent window 5 on the ejector body 3 through the second groove.

[0036] The two sides of the ejector body 3 have rectangular grooves for placing transparent windows. The two sides of the ejector body 3 are sealed with two transparent windows, and the transparent windows are fixed in the rectangular grooves of the ejector body 3 by using cover plates. The primary flow nozzle 8 of the ejector is the same as that of the conventional ejector, which is a cylindrical structure.

[0037] Further, the first cover plate 6 comprises a hollow structure, and the second cover plate 7 comprises a hollow structure.

[0038] Further, the ejector body 3 is a cuboid structure, and the ejector body 3 is made of transparent material. The internal flow channel of the body 9 of the conventional ejector is a cylindrical flow channel. When observing the two-phase flow characteristics in the ejector using the visualization observation method, the curved wall surface of the body 9 of the conventional ejector will refract the light, affecting the normal illumination of the light, thereby affecting the measurement result of the liquid phase. Therefore, the ejector 2 of the present application is designed as a cuboid structure, so that the light will not be affected by the curved surface.

[0039] The present application also provides a test system for the ejector, which comprises a primary flow component, a first flow controller 13, the ejector 2 and a mixed flow component which are sequentially connected, a temperature sensor 41 and a first pressure sensor 42 are arranged between the first flow controller 13 and the ejector 2, a second pressure sensor 45 and a first temperature and humidity sensor 46 are arranged between the ejector 2 and the mixed flow component, the ejector 2 is connected with a secondary flow component, a third pressure sensor 43 and a second temperature and humidity sensor 44 are arranged between the ejector 2 and the secondary flow component, a flow control group is arranged on the secondary flow component, the temperature sensor 41, the first pressure sensor 42, the second pressure sensor 45, the first temperature and humidity sensor 46, the third pressure sensor 43 and the second temperature and humidity sensor 44 are respectively connected with a signal acquisition and processing module 50, a light source emitting end 47 is arranged on one side of the ejector 2, and a light source receiving end 48 is arranged on the other side of the ejector 2.

[0040] The test system contains three gas supplies, one of which is a hydrogen gas source supplying the primary flow of the ejector 2, and the other two are hydrogen and nitrogen gas sources, which are mixed by heating, humidifying and liquid droplet mixing to generate a two-phase multi-component mixture to supply the secondary flow of the ejector 2.

[0041] The macroscopic performance measurement of the ejector 2 includes the measurement of the variation characteristics of the flow rate, temperature and pressure. The flow rate, temperature and pressure of the primary flow FA are measured by the first flow controller 13, the temperature sensor 41 and the first pressure sensor 42 respectively. The flow rates of hydrogen and nitrogen in the secondary flow FB are measured by the flow controller group. The humidity of the secondary flow is obtained by the second temperature and humidity sensor 44, and the temperature value is also measured. The pressure of the secondary flow is measured by the third pressure sensor 43. The pressure, temperature and humidity at the outlet of the ejector 2 are measured by the second pressure sensor 45 and the first temperature and humidity sensor 46 respectively.

[0042] The local flow characteristics of the ejector 2 are measured by a visualization test method. The part of the ejector body 3 in the test system is made of transparent material, and the two-phase flow characteristics inside the ejector 2 are observed by visualization methods such as shadow method or laser particle size analysis. Taking the shadow method as an example, the light source emitting end 47 emits a light source, and the light passes through the transparent window of the ejector. When the light encounters fluid media with different densities in the ejector, it will be refracted to different degrees, so that the light intensity received by the light receiving end 48 will be weakened. After the light receiving end 48 receives the light intensity signal, the light intensity distribution characteristics are processed by the signal acquisition and processing module 50, and the light intensity distribution characteristics of the light receiving end 48 are converted into flow characteristics such as shock wave and liquid droplet distribution.

[0043] The signal acquisition and processing module 50 acquires the data of the macroscopic physical quantities of the ejector 2 collected by the pressure flow and pressure sensors, and also acquires the two-phase flow characteristic data of the liquid droplet distribution in the ejector 2. By comparing and analyzing the macroscopic physical quantities and the local liquid droplet flow characteristics, the performance variation law of the ejector 2 is comprehensively mastered, the design and application of the ejector 2 are improved, and the stable and efficient operation of the stack is ensured.

[0044] Further, the primary flow assembly includes a high-pressure hydrogen gas cylinder 11, and the high-pressure hydrogen gas cylinder 11, the first pressure reducing valve 12 and the first flow controller 13 are connected in sequence.

[0045] The primary flow FA of the ejector is high-purity hydrogen. The hydrogen is supplied by the high-pressure hydrogen gas cylinder 11, and the hydrogen passes through the first pressure reducing valve 12 and the first flow controller 13 in sequence and then is supplied to the ejector 2. The function of the first pressure reducing valve 12 is to control the pressure of the hydrogen released from the high-pressure hydrogen gas cylinder 11 to avoid the direct impact of high pressure on the first flow controller 13. The function of the first flow controller 13 is to control the flow rate of the primary flow hydrogen supplied to the ejector 2 and to measure the flow rate value.

[0046] Further, the mixed flow assembly comprises a pressure regulating chamber 14, the ejector 2, the pressure regulating chamber 14 and a tail gas recovery tank 15 are connected in sequence, the second pressure sensor 45 and the first temperature and humidity sensor 46 are arranged between the ejector 2 and the pressure regulating chamber 14.

[0047] The primary flow FA and the secondary flow FB of the ejector 2 are mixed in the ejector 2, and the mixed flow FC discharged from the ejector 2 enters the pressure regulating chamber 14, the function of the pressure regulating chamber 14 is to control the outlet pressure of the ejector 2 to be equal to the pressure of the fuel cell stack. The final mixed flow FC enters the tail gas recovery tank 15 for storage.

[0048] Further, the flow control assembly comprises a second flow controller 23 and a third flow controller 33, the secondary flow assembly comprises a hydrogen assembly and a nitrogen assembly connected with each other, the hydrogen assembly comprises a hydrogen cylinder 21, a second pressure reducing valve 22, the second flow controller 23, a first heating and humidifier 24 and a gas-liquid mixer 25 connected in sequence, the nitrogen assembly comprises a nitrogen cylinder 31, a third pressure reducing valve 32, the third flow controller 33, a second heating and humidifier 34, a first needle valve 35 and the gas-liquid mixer 25 connected in sequence, the second heating and humidifier 34, a second needle valve 36, an atomization assembly are connected with the gas-liquid mixer 25, the gas-liquid mixer 25 is connected with the ejector 2, and the third pressure sensor 43 and the second temperature and humidity sensor 44 are arranged between the gas-liquid mixer 25 and the ejector 2.

[0049] The nitrogen of the secondary flow passes through the heating and humidifier, and is divided into two paths, one of which directly enters the mixing tank, and the other of which drives the liquid droplet atomization as a gas source.

[0050] The flow rates of hydrogen and nitrogen in the secondary flow FB are measured by the second flow controller 23 and the third flow controller 33 respectively.

[0051] The secondary flow FB of the ejector is a two-phase multi-component mixture of hydrogen, nitrogen, saturated water vapor and liquid water. Hydrogen and nitrogen are supplied by hydrogen cylinder 21 and nitrogen cylinder 31 respectively, and the flow values of the supplied hydrogen and nitrogen are controlled by second flow controller 23 and third flow controller 33 respectively. Second pressure reducing valve 22 and third pressure reducing valve 32 are used to control the pressure of the gas discharged from the high-pressure cylinders, avoiding the direct impact of high-pressure on the flow control valve group. First heating and humidifying device 24 and second heating and humidifying device 34 are used to heat and humidify the hydrogen and nitrogen respectively. The heating temperature reaches the fuel cell stack exhaust temperature, generally 60-80°C. Humidification is to add water vapor components so that the secondary flow of the ejector 2 contains saturated water vapor. First needle valve 35 and second needle valve 36 are used to divide the heated and humidified nitrogen into two parts, one part enters gas-liquid mixer 25, and the other part drives the generation of liquid droplets as a power source. The core device for generating liquid droplets is the atomization assembly, which atomizes liquid water into liquid droplets through gas jet. The particle size of the atomized droplets is controlled by adjusting the nitrogen pressure through second needle valve 36, and the flow of the atomized droplets is controlled by adjusting the water injection pressure of water tank 38. Finally, hydrogen, nitrogen, saturated water vapor and liquid water form a two-phase multi-component mixture in gas-liquid mixer 25 as the secondary flow FB of the ejector. The method of independent heating and humidification of nitrogen and driving liquid droplet atomization can safely and effectively produce a two-phase multi-component mixture that meets the actual working conditions.

[0052] Further, the atomization assembly comprises a liquid droplet atomization nozzle 37 and a water tank 38 connected in sequence, and the second needle valve 36, the liquid droplet atomization nozzle 37 and the gas-liquid mixer 25 are connected in sequence.

[0053] The core device for generating liquid droplets is the liquid droplet atomization nozzle 37, which atomizes liquid water from the water tank 38 into liquid droplets through gas jet. The particle size of the atomized droplets is controlled by adjusting the nitrogen pressure through second needle valve 36, and the flow of the atomized droplets is controlled by adjusting the water injection pressure of water tank 38. The method of independent heating and humidification of nitrogen and driving liquid droplet atomization can safely and effectively produce a two-phase multi-component mixture that meets the actual working conditions.

[0054] Figure 5 and Figure 6 are the macroscopic performance and visualized flow characteristics of the ejector tested by the test system of the present application respectively. Therefore, the system is used for comprehensive testing of the ejector 2 of the fuel cell, which can not only accurately test the changes of the macroscopic physical quantities of the ejector 2, but also monitor the local flow characteristics of the ejector 2 in the fuel cell system. The system can comprehensively test the characteristics of the ejector 2 of the fuel cell system in all directions, which can perfect the design and application of the ejector 2 and ensure the stable and efficient operation of the stack.

[0055] While the application has been described above with reference to particular embodiments, it is to be understood that the application is not limited to the disclosed configurations and details, and that numerous modifications can be made within the scope of the application. The application is defined by the appended claims, and the scope of the application is intended to encompass all modifications within the scope of the claims, and any equivalents thereof.

Claims

1. An ejector test system characterized by: The ejector comprises a primary flow component, a first flow controller, the ejector and a mixed flow component connected in sequence, a temperature sensor and a first pressure sensor are arranged between the first flow controller and the ejector, a second pressure sensor and a first temperature and humidity sensor are arranged between the ejector and the mixed flow component, the ejector is connected with a secondary flow component, a third pressure sensor and a second temperature and humidity sensor are arranged between the ejector and the secondary flow component, a flow control group is arranged on the secondary flow component, the temperature sensor, the first pressure sensor, the second pressure sensor, the first temperature and humidity sensor, the third pressure sensor and the second temperature and humidity sensor are connected with a signal acquisition and processing module respectively, a light source emitting end is arranged on one side of the ejector, and a light source receiving end is arranged on the other side of the ejector. The ejector comprises a first visible component, an ejector body and a second visible component connected in sequence, the ejector body is connected with a primary flow nozzle, a flow channel is arranged in the ejector body, the flow channel is composed of a plurality of planes, and a primary flow inlet, a secondary flow inlet and an outlet are arranged on the ejector body.

2. The ejector test system of claim 1, wherein: The first visible component comprises a first cover plate and a first perspective window, the second visible component comprises a second perspective window and a second cover plate, and the first cover plate, the first perspective window, the ejector body, the second perspective window and the second cover plate are connected in sequence.

3. The ejector test system of claim 2, wherein: First and second grooves are arranged on the ejector body, the first cover plate fixes the first perspective window on the ejector body through the first groove, and the second cover plate fixes the second perspective window on the ejector body through the second groove.

4. The ejector tester system of claim 3, wherein: The first cover plate comprises a hollow structure, and the second cover plate comprises a hollow structure.

5. The ejector test system of claim 4, wherein: The ejector body is a cuboid structure, and the ejector body is made of transparent material.

6. The ejector testing system of any of claims 1-5, wherein: The primary flow component comprises a high-pressure hydrogen cylinder, the high-pressure hydrogen cylinder, a first pressure reducing valve and the first flow controller are connected in sequence.

7. The ejector tester system of claim 6, wherein: The mixed flow component comprises a pressure adjusting cavity, the ejector, the pressure adjusting cavity and a tail gas recovery tank are connected in sequence, and the second pressure sensor and the first temperature and humidity sensor are arranged between the ejector and the pressure adjusting cavity.

8. The ejector tester system of claim 7, wherein: The flow control group comprises a second flow controller and a third flow controller, the secondary flow component comprises a hydrogen component and a nitrogen component connected with each other, the hydrogen component comprises a hydrogen cylinder, a second pressure reducing valve, the second flow controller, a first heating and humidifying device and a gas-liquid mixer connected in sequence, the nitrogen component comprises a nitrogen cylinder, a third pressure reducing valve, the third flow controller, a second heating and humidifying device, a first needle valve and the gas-liquid mixer connected in sequence, the second heating and humidifying device, a second needle valve, an atomization component and the gas-liquid mixer are connected, the gas-liquid mixer is connected with the ejector, and the third pressure sensor and the second temperature and humidity sensor are arranged between the gas-liquid mixer and the ejector.

9. The ejector test system of claim 8, wherein: The atomizing assembly comprises a liquid droplet atomizing nozzle and a water tank connected with each other, and the second needle valve, the liquid droplet atomizing nozzle and the gas-liquid mixer are sequentially connected.

Images