High-power composite adjustable hydrogen recycling ejector device

Abstract

The invention relates to a high-power composite adjustable hydrogen recycling ejector device which comprises an electromagnetic control mechanism, an ejector body assembly and a composite adjusting nozzle assembly, the composite adjusting nozzle assembly comprises a movable needle valve, a fixed nozzle, a sliding nozzle and double springs connected in series, and the composite adjusting nozzle assembly is nested in an ejector body. When load current changes, the electromagnetic control mechanism drives the needle valve to move in a reciprocating mode, the spring between the fixed nozzle and the sliding nozzle and the spring between the sliding nozzle and the needle valve can be compressed at the same time, and therefore the sectional area of an outlet of the sliding nozzle and the distance between the sliding nozzle and the mixing chamber can be changed at the same time only by adjusting displacement of the needle valve. According to the invention, the problems of single adjustment mode or complex multi-target adjustment structure of the existing ejector and unstable movement of the existing needle valve structure are solved, and active, rapid, stable and continuous composite adjustment of the hydrogen recirculation ejector during load change of a fuel cell system is realized; and the applicable power range of the ejector is better expanded.

Description

Technical Field

[0001] The invention relates to the field of ejectors for fuel cells, and in particular to a high-power composite adjustable hydrogen recycling ejector device. Background Art

[0002] With the continuous deterioration of the environment caused by fossil fuels and the realization of the carbon neutrality goal, hydrogen energy, as one of the alternative clean energy sources, is accelerating its development. Since hydrogen fuel cells use hydrogen as fuel and only produce pollution-free water as an additive, they are becoming a new energy power device with great potential in the new century, and are gradually being used in automobiles, ships and aircraft. Among them, proton exchange membrane fuel cells have gradually become the best candidate to replace internal combustion engines due to their advantages such as zero emissions, high efficiency, high power density, and fast cold start. Hydrogen-powered vehicles have also become one of the most potential alternatives to internal combustion vehicles.

[0003] For high-power fuel cell systems, it is usually necessary to use an excessive hydrogen supply method to avoid performance degradation due to lack of reactants in the stack. Therefore, the hydrogen that is not completely consumed in the proton exchange membrane fuel cell stack needs to be recycled and reused to improve the utilization rate of hydrogen. A circulation device needs to be set up in the anode circulation system to recover the hydrogen, water vapor and part of the nitrogen in the stack. At present, the circulation device includes two categories: mechanical pumps and ejectors: mechanical pumps have a wide control range, but require additional power supply, and are large in size and prone to noise; in contrast, ejectors use the Venturi principle to eject the cycle through their own energy, with small size, low noise, no power loss, and low maintenance cost, making them the best choice for recycling hydrogen in many fuel cell systems.

[0004] At present, the ejectors involved mainly include single-nozzle fixed structure ejectors, multi-nozzle or multi-stage ejectors, and needle valve ejectors. The single-nozzle fixed structure ejector is designed based on a certain rated operating point, and the ejection performance is optimal only at this operating point. When it deviates from the rated operating point, the ejection performance will drop sharply and cannot adapt to the fuel cell system with variable load conditions. Although multi-nozzle or multi-stage ejectors have improved the working range to a certain extent, their applicable power range is still limited due to the inability to continuously adjust, and the system control is more complicated. Each nozzle needs to be controlled separately and is larger in size. When the mode is switched, it will cause airflow collision and oscillation.

[0005] In addition, existing needle valve type ejectors such as Chinese patent CN115898971A can only change the cross-sectional area of ​​the nozzle outlet, but cannot change the distance between the nozzle and the mixing chamber at the same time. In addition, the existing needle valve is too long, resulting in unstable movement, which is not suitable for large and heavy-loaded commercial vehicles in complex road conditions. Most of them rely on passive regulation of flow and pressure, and it is difficult to achieve active, rapid, stable and continuous compound regulation under variable load conditions of the system, and cannot meet the dynamic response requirements of the fuel cell system. Summary of the invention

[0006] The purpose of the present invention is to provide a high-power composite adjustable hydrogen recirculation ejector device, which can actively, quickly and continuously adjust the current signal of the proportional electromagnetic control mechanism when the fuel cell load changes, thereby realizing the above-mentioned composite adjustment strategy and ultimately improving its entrainment performance at the desired hydrogen flow rate.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] A high-power composite adjustable hydrogen recirculation ejector device comprises an electromagnetic control mechanism, an ejector body component and a composite regulating nozzle component.

[0009] The composite regulating nozzle assembly comprises a fixed nozzle, a sliding nozzle, a needle valve, a needle valve spring and a sliding nozzle spring. The outlet side of the main channel of the fixed nozzle is provided with a first annular baffle plate which is radially expanded inwards. The needle valve and the sliding nozzle are both arranged in the main channel of the fixed nozzle and slide axially along the main channel of the fixed nozzle. The end of the needle valve is conical and is provided with a second annular baffle plate which is radially expanded outwards. The inlet side of the sliding nozzle is provided with a third annular baffle plate which is radially expanded outwards. The second annular baffle plate, the third annular baffle plate and the first annular baffle plate are arranged in sequence along the air flow direction. One end of the needle valve spring is supported on the second annular baffle plate, and the other end is supported on the first side of the third annular baffle plate. One end of the sliding nozzle spring is supported on the second side of the third annular baffle plate, and the other end is supported on the first annular baffle plate. The head end of the needle valve is connected to the electromagnetic control mechanism, and the end end is inserted into the sliding nozzle and passes through the outlet section of the sliding nozzle. The main channels in the needle valve, the fixed nozzle, the sliding nozzle and the ejector body assembly are all coaxially arranged.

[0010] The electromagnetic control mechanism pushes the needle valve to move toward one end of the mixing chamber of the ejector body assembly according to the change of the fuel cell load current. During the movement of the needle valve, the needle valve spring and the sliding nozzle spring are compressed at the same time. When the sliding nozzle approaches the mixing chamber of the ejector body assembly, the needle valve moves relative to the sliding nozzle to change the cross-sectional area of ​​the channel between the needle valve and the sliding nozzle.

[0011] The outer edges of the second annular baffle plate, the third annular baffle plate and the first annular baffle plate are all supported on the inner wall of the main channel of the fixed nozzle, and the second annular baffle plate is provided with a needle valve hole.

[0012] The needle valve holes are provided in plurality and are arranged around the second annular baffle.

[0013] The ejector body assembly includes an ejector body, a primary flow tube, a secondary flow tube and a mixing outlet tube. A primary flow receiving chamber, a mixed flow receiving chamber, a mixing chamber and a diffusion chamber are sequentially arranged in the ejector body. The primary flow tube, the secondary flow tube and the mixing outlet tube are all connected to the ejector body. The primary flow tube is connected to the primary flow receiving chamber through a primary air inlet channel, the secondary flow tube is connected to the mixing flow receiving chamber, the mixing outlet tube is connected to the output side of the diffusion chamber, and the secondary flow tube and the mixing outlet tube are arranged on the same side, the primary flow tube is located on the opposite side of the secondary flow tube, and the fixed nozzle is located in the primary flow receiving chamber and the mixing flow receiving chamber.

[0014] The secondary flow tube is fixed on the ejector body by secondary flow tube screws, and the mixing outlet tube is fixed on the ejector body by mixing outlet tube screws.

[0015] The inlet of the primary flow pipe serves as a primary flow inlet, the inlet of the secondary flow pipe serves as a secondary flow inlet, and the outlet of the mixing outlet pipe serves as a mixing flow outlet.

[0016] The electromagnetic control mechanism includes an electromagnet housing, an end cover, and a coil, a guide sleeve, an armature and an armature spring arranged in the electromagnet housing. The coil sleeve is arranged on the outside of the armature. The first section of the armature is provided with a protruding column. The diameter of the protruding column is smaller than the support of the main part of the armature. The main part of the protruding column armature forms a supporting step surface. One end of the armature spring is supported on the supporting step surface, and the other end is supported on the inner wall of the electromagnet housing. The end cover is fixed at the entrance of the main channel of the fixed nozzle. The armature is connected to the head end of the needle valve. The needle valve rod of the needle valve passes through the end cover.

[0017] When the load current of the fuel cell system is maximum, the current in the coil is maximum, the electromagnetic force between the armature and the electromagnet housing is maximum, the armature spring is subjected to maximum force, and the armature drives the needle valve away from the sliding nozzle to increase the cross-sectional area of ​​the sliding nozzle outlet and increase the distance between the sliding nozzle and the mixing chamber. When the load current is minimum, the electromagnetic force between the armature and the electromagnet housing is maximum and the electromagnetic force is minimum, the armature spring is subjected to minimum force, and the armature drives the needle valve close to the sliding nozzle to reduce the cross-sectional area of ​​the sliding nozzle outlet and reduce the distance between the sliding nozzle and the mixing chamber.

[0018] The sliding nozzle also includes a primary flow equal area chamber, a primary flow convergence chamber and a sliding nozzle outlet. The primary flow equal area chamber and the primary flow convergence chamber are arranged along the air flow direction. The primary flow equal area chamber and the primary flow convergence chamber are continuous buffer zones for the primary flow to prevent air flow shock caused by sudden changes in the cross section. The sliding nozzle outlet is connected to the mixed flow receiving chamber.

[0019] The fixed nozzle includes an axially connected end cover mounting ring and a nozzle body. The end cover mounting ring is provided with a countersunk hole for connecting to the ejector body and a screw hole for connecting to the electromagnetic control mechanism. The nozzle body is provided with a primary flow channel, and the internal main channel serves as a sliding area. The needle valve and the sliding nozzle are both gap-matched with the sliding area in the fixed nozzle.

[0020] The end of the needle valve is in a cone shape.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. By adopting a proportional electromagnetic control mechanism to proportionally adjust the needle valve displacement, the change of the electromagnetic force can be controlled in real time according to the change of the load current. Compared with the existing passive adjustment scheme using flow or pressure, the present invention can realize the active, rapid and continuous adjustment of the sliding nozzle outlet cross-sectional area, meet the wide range requirements of the ejector under the variable load condition of the fuel cell, and improve the performance of the ejector under all working conditions. The specific range of improvement can be reflected in the following description and simulation.

[0023] 2. The proportional electromagnetic control mechanism and the ejector body assembly are designed as an integral whole. The compound adjustment function can be achieved by only driving the needle valve. The sliding nozzle outlet cross-sectional area and the distance between the sliding nozzle and the mixing chamber can be adjusted simultaneously according to the changes in load conditions, further improving the ejector entrainment ratio under the same conditions. The overall structure is simpler and the response speed is faster.

[0024] 3. Slide one end of the cylindrical surface of the needle valve with the end cover of the proportional electromagnetic mechanism, and slide the other end in the sliding area of ​​the fixed nozzle. This can significantly improve the stability of the needle valve during movement and is more suitable for large and heavy-loaded commercial vehicles driving in complex road conditions.

[0025] 4. The spring stiffness of the needle valve spring and the sliding nozzle spring described in the present invention can be designed according to the electromagnetic force of the proportional electromagnetic control mechanism and the friction force between the needle valve and the sliding nozzle, and the spring stiffness is proportional to the spring compression amount. The design range can be determined according to the later compression amount, and then the stiffness value of the spring can be determined.

[0026] 5. The composite adjustable structure adopted by the present invention can solve the problem of unstable flow caused by nozzle switching of the multi-nozzle ejector and the problem of being unable to continuously adjust the nozzle outlet area, further improving the applicable power range of the ejector. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is an overall cross-sectional structural diagram of a high-power composite adjustable hydrogen recirculation ejector device described in the present invention.

[0028] Figure 2 This is a cross-sectional view of the structure of the ejector body assembly described in the present invention.

[0029] Figure 3 It is a structural cross-sectional view and a left side view of the fixed nozzle of the present invention.

[0030] Figure 4 For the Figure 2 BB cross-sectional view.

[0031] Figure 5 It is a schematic diagram of the three-dimensional structure of the fixed nozzle described in the present invention.

[0032] Figure 6 This is a cross-sectional view of the needle valve structure of the present invention.

[0033] Figure 7 It is the right view of the needle valve structure of the present invention.

[0034] Figure 8 This is a cross-sectional view of the sliding nozzle structure of the present invention.

[0035] Figure 9(a) shows the working state of the ejector when the load current is maximum (the sliding nozzle outlet cross-sectional area is the largest, and the distance between the sliding nozzle and the mixing chamber is L). nxp maximum).

[0036] Figure 9(b) shows the working state of the ejector when the load current is in the middle (the cross-sectional area of ​​the sliding nozzle outlet is in the middle, and the distance between the sliding nozzle and the mixing chamber is L nxp in the middle).

[0037] Figure 9(c) shows the working state of the ejector when the load current is minimum (the sliding nozzle outlet cross-sectional area is minimum, and the distance between the sliding nozzle and the mixing chamber is L). nxp minimum).

[0038] Fig.10 This is the velocity simulation cloud diagram of the nozzle area of ​​the traditional fixed structure ejector when the load current is 60A.

[0039] Fig.11 This is a simulated cloud diagram of the velocity in the nozzle area of ​​the composite adjustable ejector of the present invention when the load current is 60A.

[0040] Fig.12 It is a comparison chart of the ejector entrainment ratio of the traditional fixed structure ejector and the composite adjustable ejector of the present invention under different load currents.

[0041] Fig.13 This is a comparison diagram of ejector entrainment ratios of a conventional fixed structure ejector and the composite adjustable ejector of the present invention at different stack output powers;

[0042] Wherein: 1. electromagnetic control mechanism, 2. fixed nozzle, 3. secondary flow inlet, 4. mixed flow outlet, 5. primary flow inlet, 6. needle valve, 7. needle valve spring, 8. sliding nozzle spring, 9. sliding nozzle, 10. ejector body assembly, 101. electromagnet housing, 102. coil, 103. guide sleeve, 104. end cover, 105. needle valve sealing ring, 106. end cover sealing ring, 107. limit plate, 108. current signal connector, 109. armature, 110. armature spring, 201. primary flow channel, 202. sliding area, 203. countersunk hole, 204. screw hole, 205 and 205, sealing ring, 601. needle valve rod, 602. Needle valve hole, 603, second annular baffle, 604, needle valve cone, 901, third annular baffle, 902, primary flow equal area chamber, 903, primary flow convergence chamber, 904, sliding nozzle outlet, 1001, primary flow tube seal, 1002, primary air inlet channel, 1003, primary flow receiving chamber, 1004, secondary flow tube screw, 1005, secondary flow tube, 1006, secondary flow tube seal, 1007, mixing outlet tube screw, 1008, mixing outlet tube seal, 1009, mixing outlet tube, 1010, ejector body, 1011, diffusion chamber, 1012, mixing chamber, 1013, mixing flow receiving chamber, 1014, primary flow tube. DETAILED DESCRIPTION

[0043] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0044] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0045] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying 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, and therefore cannot be understood as limiting the present invention. In addition, the terms "proximal", "distal", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. Physical quantities in formulas, if not separately marked, should be understood as basic quantities of the base units of the International System of Units, or derived quantities derived from the basic quantities through mathematical operations such as multiplication, division, differentiation or integration.

[0046] In addition, the terms "horizontal", "vertical", "overhanging" and the like do not mean that the components are required to be absolutely horizontal or overhanging, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0047] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] In conjunction with the accompanying drawings, some embodiments of the present invention are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0049] A high-power composite adjustable hydrogen recirculation ejector device, such as Figures 1 to 8 As shown, it includes an electromagnetic control mechanism 1, an ejector body component and a composite regulating nozzle component. The electromagnetic control mechanism 1 adopts a proportional control method.

[0050] The composite regulating nozzle assembly comprises a fixed nozzle 2, a sliding nozzle 9, a needle valve 6, a needle valve spring 7 and a sliding nozzle spring 8. A first annular baffle plate extending radially inward is provided on the outlet side of the main channel of the fixed nozzle 2. The needle valve 6 and the sliding nozzle 9 are both arranged in the main channel of the fixed nozzle 2 and slide axially along the main channel of the fixed nozzle 2. The end of the needle valve 6 is conical and a second annular baffle plate 603 extending radially outward is provided on the needle valve 6. A third annular baffle plate 901 extending radially outward is provided on the inlet side of the sliding nozzle 9. The second annular baffle plate 603 and the third annular baffle plate 901 extend radially outward. The annular baffle 901 and the first annular baffle are arranged in sequence along the airflow direction, one end of the needle valve spring 7 is supported on the second annular baffle 603, and the other end is supported on the first side of the third annular baffle, one end of the sliding nozzle spring 8 is supported on the second side of the third annular baffle, and the other end is supported on the first annular baffle, the head end of the needle valve 6 is connected to the electromagnetic control mechanism 1, and the tail end is inserted into the sliding nozzle 9 and passes through the outlet section of the sliding nozzle 9, and the needle valve 6, the fixed nozzle 2, the sliding nozzle 9 and the main channel in the ejector body assembly are all coaxially arranged;

[0051] The electromagnetic control mechanism 1 pushes the needle valve 6 to move toward one end of the mixing chamber 1012 of the ejector body assembly according to the change of the fuel cell load current. During the movement of the needle valve 6, the needle valve spring 7 and the sliding nozzle spring 8 are compressed at the same time. When the sliding nozzle 9 approaches the mixing chamber 1012 of the ejector body assembly, the needle valve 6 moves relative to the sliding nozzle 9 to change the channel cross-sectional area between the needle valve 6 and the sliding nozzle 9.

[0052] like Figure 2 As shown, the ejector body assembly includes an ejector body 1010, a primary flow tube 1014, a secondary flow tube 1005 and a mixing outlet tube 1009. The ejector body 1010 is provided with a primary flow receiving chamber 1003, a mixing flow receiving chamber 1013, a mixing chamber 1012 and a diffusion chamber 1011 in sequence. The primary flow tube 1014, the secondary flow tube 1005 and the mixing outlet tube 1009 are all connected to the ejector body 1010. The primary flow tube 1014 is connected to the primary flow receiving chamber 1003 through the primary air inlet channel 1002. The secondary flow tube 1005 is connected to the mixing flow receiving chamber 1013. The mixing outlet tube 1009 is connected to the output side of the diffusion chamber 1011. The secondary flow tube 1005 and the mixing outlet tube 1009 are arranged on the same side. The primary flow tube 1014 is located on the opposite side of the secondary flow tube 1005. The fixed nozzle 2 is located in the primary flow receiving chamber 1003 and the mixing flow receiving chamber 1013. The primary flow inlet 5, the secondary flow inlet 3 and the mixed flow outlet 4 are arranged on the ejector body assembly 10. The two fluids are fully mixed in the mixing chamber 1012 to increase the pressure of the mixed flow. The pressure of the mixed flow is further increased in the diffusion chamber 1011 to meet the pressure requirements at the inlet of the fuel cell stack.

[0053] The primary flow receiving chamber 1003, the mixed flow receiving chamber 1013, the mixing chamber 1012, and the diffusion chamber 1011 are connected in sequence on the main axis of the ejector body 1010. The primary flow tube 1014 is connected to the ejector body 1010 together with the primary flow tube seal 1001 through its own thread. The secondary flow tube 1005 and the mixing outlet tube 1009 are connected to the ejector body 1010 through the secondary flow tube screw 1004 and the mixing outlet tube screw 1007 respectively. The primary flow tube 1014 and the secondary flow tube 1005 are distributed on both sides of the axis of the ejector body 1010. The secondary flow tube 1005 and the mixing outlet tube 1009 are on the same side of the ejector body, and they form a complete fluid flow channel.

[0054] The secondary flow tube 1005 is fixed to the ejector body 1010 by means of the secondary flow tube screw 1004 , and the mixing outlet tube 1009 is fixed to the ejector body 1010 by means of the mixing outlet tube screw 1007 .

[0055] The inlet of the primary flow tube 1014 serves as the primary flow inlet 5 , the inlet of the secondary flow tube 1005 serves as the secondary flow inlet 3 , and the outlet of the mixing outlet tube 1009 serves as the mixing flow outlet 4 .

[0056] Among them, Figure 8 As shown, the third annular baffle 901 is used to compress the sliding nozzle spring 8 to change the distance between the sliding nozzle 9 and the mixing chamber 1012. In addition, the sliding nozzle 9 also includes a primary flow equal area chamber 902, a primary flow convergence chamber 903 and a sliding nozzle outlet 904. The primary flow equal area chamber 902 and the primary flow convergence chamber 903 are arranged along the air flow direction. The primary flow equal area chamber 902 and the primary flow convergence chamber 903 are continuous buffer zones for the primary flow to prevent air flow shocks caused by sudden changes in the cross section. The sliding nozzle outlet 904 is connected to the mixing flow receiving chamber 1013.

[0057] There are multiple needle valve holes 602 , which are arranged around the second annular baffle 603 .

[0058] The fixed nozzle 2 includes an axially connected end cap mounting ring and a nozzle body. The end cap mounting ring is provided with a countersunk hole 203 for connecting the ejector body 1010 and a screw hole 204 for connecting the electromagnetic control mechanism 1. The nozzle body is provided with a primary flow channel 201. The internal main channel serves as a sliding area 202. The needle valve 6 and the sliding nozzle 9 are both gap-matched with the sliding area 202 in the fixed nozzle 2. Figure 3 , 45 are a schematic diagram and a three-dimensional diagram of the overall structure of the fixed nozzle 2, including four primary flow channels 201, a sliding area 202, three countersunk holes 203, three screw holes 204, and a sealing ring 205 and a sealing ring 206 shown in FIG9 . The needle valve 6 and the sliding nozzle 9 are clearance-matched in the sliding area 202, the fixed nozzle 2 is connected to the ejector body through the countersunk hole 203, and the proportional electromagnetic control mechanism 1 is connected to the fixed nozzle through the screw hole 204, making the structure more compact and reasonable, and easy to disassemble and replace wearing parts.

[0059] The outer edges of the second annular baffle 603, the third annular baffle 901 and the first annular baffle are all supported on the inner wall of the main channel of the fixed nozzle 2, and the second annular baffle 603 is provided with a needle valve hole 602. The needle valve 6 and the sliding nozzle 9 are both clearance-matched with the sliding area 202 in the fixed nozzle 2, which can further improve the stability of the needle valve 6 and the sliding nozzle 9 during the sliding process, so as to adapt to the driving environment with complex road conditions, such as Figure 6 , 7 As shown, the needle valve stem 601 of the needle valve is cylindrical, the needle valve cone 604 is conical, and the cone 604 moves inside the sliding nozzle 9 to linearly change the outlet cross-sectional area of ​​the sliding nozzle 9. The second annular baffle 603 is used to compress the needle valve spring 7.

[0060] Combination Figure 1 , 2 , 3, 6, 8, the primary flow inlet 5 is arranged on the primary flow tube 1014, and together with the primary air inlet channel 1002, the primary flow receiving chamber 1003, the primary flow channel 201, the needle valve hole 602, the primary flow equal area chamber 902, the primary flow convergence chamber 903 and the sliding nozzle outlet 904 form a flow area of ​​the primary flow.

[0061] The secondary flow inlet 3 is arranged on the secondary flow tube 1005 and is connected to the mixed flow receiving chamber 1013. After being mixed with the primary flow, it passes through the mixing chamber 1012, the diffusion chamber 1011, and the mixing outlet pipe 1009 to reach the mixed flow outlet 4 to supply the gas flow required by the fuel cell stack.

[0062] As shown in FIG9 , the electromagnetic control mechanism 1 comprises an electromagnet housing 101, an end cover 104, and a coil 102, a guide sleeve 103, an armature 109 and an armature spring 110 arranged in the electromagnet housing 101. The coil 102 is sleeved on the outside of the armature 109. The first section of the armature 109 is provided with a protruding column. The diameter of the protruding column is smaller than the support of the main part of the armature 109. The main part of the protruding column armature 109 forms a supporting step surface. One end of the armature spring 110 is supported on the supporting step surface, and the other end is supported on the inner wall of the electromagnet housing 101. The end cover 104 is fixed to the entrance of the main channel of the fixed nozzle 2. The armature 109 is connected to the head end of the needle valve 6. The needle valve rod 601 of the needle valve 6 is arranged through the end cover 104. The guide sleeve 103 is arranged between the armature 109 and the coil 102 to protect the coil and prevent the coil from being worn and broken. A limit plate 107 is arranged on one side of the end cover 104.

[0063] When the load current of the fuel cell system is maximum, the current in the coil 102 is maximum, the electromagnetic force between the armature 109 and the electromagnet housing 101 is maximum, the armature spring 110 is subjected to maximum force, and the armature 109 drives the needle valve 6 away from the sliding nozzle 9 to increase the cross-sectional area of ​​the sliding nozzle outlet 904 and increase the distance between the sliding nozzle 9 and the mixing chamber 1012. When the load current is minimum, the electromagnetic force between the armature 109 and the electromagnet housing 101 is maximum and minimum, the armature spring 110 is subjected to minimum force, and the armature 109 drives the needle valve 6 close to the sliding nozzle 9 to reduce the cross-sectional area of ​​the sliding nozzle outlet 904 and reduce the distance between the sliding nozzle 9 and the mixing chamber 1012.

[0064] Since the needle valve spring 7 is installed between the needle valve 6 and the sliding nozzle 9, and the sliding nozzle spring 8 is installed between the sliding nozzle 9 and the fixed nozzle 2, when the load current or the fuel cell power is the largest, the needle valve spring 7 and the sliding nozzle spring 8 are set to a free state (not compressed), as shown in FIG9(a). At this time, the sliding nozzle 9 outlet opening is the largest, and the distance between the sliding nozzle 9 and the mixing chamber 1012 is also the largest. When the load current or the fuel cell power is in an intermediate state, the needle valve spring 7 and the sliding nozzle spring 8 are compressed to an intermediate state, as shown in FIG9(b). At this time, the sliding nozzle 9 outlet opening is in an intermediate state, and the distance between the sliding nozzle 9 and the mixing chamber 1012 is also in an intermediate state. When the load current or the fuel cell power is the smallest, the armature 109 drives the needle valve 6 to continue to move toward the mixing chamber 1012 side, as shown in FIG9(c). The needle valve spring 7 and the sliding nozzle spring 8 are compressed to the minimum at the same time. At this time, the sliding nozzle 9 outlet opening is the smallest, and the distance between the sliding nozzle 9 and the mixing chamber 1012 is also the smallest. The relationship between the force and the compression amount of the spring is as follows:

[0065] F=k1·X1=k2·X2

[0066] X=X1+X2

[0067] In the formula, F represents the spring force, k1 and k2 represent the spring stiffness of the needle valve spring 7 and the sliding nozzle spring 8 respectively, X1 represents the compression of the needle valve spring 7 (that is, the moving distance of the needle valve 6 relative to the sliding nozzle 9), X2 represents the compression of the sliding nozzle spring 8 (that is, the moving distance of the sliding nozzle 9 relative to the mixing chamber 1012), and X represents the moving displacement of the needle valve 6 (that is, the sum of the compression of the needle valve spring 7 and the sliding nozzle spring 8).

[0068] The force on the needle valve spring 7 is equal to the force on the sliding nozzle spring 8. It can be designed according to the friction between the needle valve 6 and the sliding nozzle 9 and the electromagnetic force of the electromagnetic control mechanism 1, and then the spring stiffness k1 of the needle valve spring 7 and the spring stiffness k2 of the sliding nozzle spring 8 are determined. The spring stiffness is proportional to the compression amount.

[0069] The force on the needle valve spring 7 is equal to the force on the sliding nozzle spring 8. It can be designed according to the friction between the needle valve 6 and the sliding nozzle 9 and the electromagnetic force of the proportional electromagnetic control mechanism 1, and then the spring stiffness k1 of the needle valve spring 7 and the spring stiffness k2 of the sliding nozzle spring 8 are determined. The spring stiffness is proportional to the compression amount.

[0070] The moving distance X1 of the needle valve 6 relative to the sliding nozzle 9 can determine the outlet cross-sectional area of ​​the sliding nozzle 9 under different load currents, and then determine the required primary flow pressure. The specific relationship between them is as follows:

[0071] A p =f(X1)

[0072]

[0073] Among them, A p represents the outlet cross-sectional area of ​​the sliding nozzle 9, p p Indicates the primary flow pressure, p s represents the secondary flow pressure, Indicates the flow correction coefficient, which is related to the structure shape of the nozzle, T p Indicates the primary flow temperature, R g,p represents the gas constant of hydrogen, k represents the adiabatic coefficient of hydrogen, N cell represents the number of fuel cell stacks, I represents the fuel cell load current, and f represents the relationship function between the moving distance of the needle valve 6 relative to the sliding nozzle 9 and the outlet cross-sectional area of ​​the sliding nozzle 9.

[0074] Fluid Simulation:

[0075] In order to compare the inherent flow field difference between the composite adjustable ejector of the present invention and the traditional fixed structure ejector under the same working conditions, the flow field simulation analysis of a 200kW proton exchange membrane fuel cell system was performed using ANSYS Fluent flow field simulation software, and the number of stacks N was set. cell is 1036. Since the entrainment ratio of the ejector will decrease sharply under low load current or low power conditions, in order to compare the difference under low load current first, we set the load current to 60A. At this time, the primary flow mass flow rate is 6.44×10 -4 kg / s, the secondary flow pressure is set to 1.3 bar, the anode pressure drop is 0.13 bar, and the compression amount X1 of the needle valve spring 7 and the compression amount X2 of the sliding nozzle spring 8 are set to be linearly related to the load current I. Specifically, when the load current I = 300A, X1 = X2 = 0mm, when the load current I = 180A, X1 = X2 = 2mm, when the load current I = 60A, X1 = X2 = 4mm, and the distance L between the sliding nozzle 9 and the mixing chamber 1012 is set nxp =6-X2. In addition, the primary flow temperature is set to 298K, the secondary flow temperature is set to 333K, and the volume fractions of secondary flow nitrogen (N2), water vapor (H2O), and hydrogen (H2) are 0.05, 0.145, and 0.805, respectively.

[0076] Fig.10 This is the velocity cloud diagram of the nozzle area of ​​the traditional fixed structure ejector when the load current is 60A obtained by simulation. It can be seen that at this time, the secondary flow ejection velocity is relatively small, and a velocity vortex phenomenon is generated, which will affect the high-speed jet, reduce its jet kinetic energy, and thus reduce the entrainment ratio of the ejector (the entrainment ratio of the ejector refers to the ratio of the secondary flow mass flow rate to the primary flow mass flow rate, which is an indicator of the ejection performance of the ejector). At the same time, the reflux phenomenon it produces will further reduce the secondary flow mass flow rate.

[0077] Fig.11 This is the velocity cloud diagram of the composite adjustable ejector nozzle area of ​​the present invention when the load current is 60A obtained through simulation. It can be clearly seen that at this time, the secondary flow ejection velocity is relatively large, and there is no vortex and backflow phenomenon that affects the ejector entrainment ratio. The ejection velocity at the secondary flow inlet is stable, which improves the ejector entrainment ratio.

[0078] In order to further obtain the comparative relationship of the entrainment ratio and the power range of the composite regulating ejector of the present invention, the load current I is set to 300A, 240A, 180A, 120A, 60A, and 30A, the secondary flow pressure is set to 2.2bar, 2bar, 1.8bar, 1.6bar, 1.3bar, and 1.2bar, and the anode pressure drop is set to 0.18bar, 0.16bar, 0.15bar, and 0.14bar. , 0.13bar, and 0.11bar, the secondary flow nitrogen gas volume fractions were 0.015, 0.017, 0.02, 0.027, 0.05, and 0.09 respectively, the secondary flow water vapor volume fractions were 0.086, 0.095, 0.107, 0.122, 0.145, and 0.163 respectively, and the secondary flow hydrogen gas volume fractions were 0.899, 0.888, 0.873, 0.851, 0.805, and 0.747 respectively.

[0079] Fig.12 , 13 The figure is a comparison chart of the ejector entrainment ratio of the traditional fixed structure ejector and the composite adjustable ejector described in the present invention under different load currents or fuel cell output powers. It can be seen that under low current or low power conditions, the entrainment ratio of the traditional fixed structure ejector drops sharply. When the entrainment ratio is greater than 1, the power range of the traditional fixed structure ejector is 70-200 kW, accounting for 65% of the entire power range, while the power range of the composite adjustable ejector described in the present invention is 20-200 kW, accounting for 90% of the entire power range. The multi-nozzle ejector described in the document "Du Z, Liu Q, Wang X, Wang L. Performance investigation on a coaxial-nozzle ejector for PEMFC hydrogen recirculation system [J]. International journal of Hydrogen Energy, 2021 (46): 38026-38039" and Chinese patent CN109873181A increases the power range to about 78%.

[0080] It can be seen that the composite adjustable ejector of the present invention has a wider working range than the multi-nozzle ejector, and solves the fluid collision and energy impact phenomena caused by the multi-nozzle ejector when multiple nozzles work simultaneously, thereby reducing energy loss. In addition, the composite adjustable ejector of the present invention solves the problems of stability and single adjustment structure of the existing needle valve type ejector.

[0081] The above are detailed and specific implementation details of the present invention. Of course, these explanations are for better illustrating the structural principles and design methods of the present invention. Corresponding structural deformations or modifications can be obtained according to the concept of the present invention without creative labor, and they should all be within the protection scope of the present invention.

Claims

1. A high-power composite adjustable hydrogen recirculation ejector device, characterized in that: It includes an electromagnetic control mechanism, an ejector body assembly and a composite regulating nozzle assembly. The composite regulating nozzle assembly comprises a fixed nozzle (2), a sliding nozzle (9), a needle valve (6), a needle valve spring (7) and a sliding nozzle spring (8); a first annular baffle plate which is radially expanded inward is provided on the outlet side of the main channel of the fixed nozzle (2); the needle valve (6) and the sliding nozzle (9) are both arranged in the main channel of the fixed nozzle (2) and slide axially along the main channel of the fixed nozzle (2); the end of the needle valve (6) is conical and a second annular baffle plate (603) which is radially expanded outward is provided on the needle valve (6); a third annular baffle plate (901) which is radially expanded outward is provided on the inlet side of the sliding nozzle (9); the second annular baffle plate (602) is provided on the inlet side of the sliding nozzle (9); and the second annular baffle plate (603) is provided on the inlet side of the sliding nozzle (9). 03), the third annular baffle (901) and the first annular baffle are arranged in sequence along the airflow direction, one end of the needle valve spring (7) is supported on the second annular baffle (603), and the other end is supported on the first side of the third annular baffle, one end of the sliding nozzle spring (8) is supported on the second side of the third annular baffle, and the other end is supported on the first annular baffle, the head end of the needle valve (6) is connected to the electromagnetic control mechanism, and the tail end is inserted into the sliding nozzle (9) and passes through the outlet section of the sliding nozzle (9), and the needle valve (6), the fixed nozzle (2), the sliding nozzle (9) and the main channel in the ejector body assembly are all coaxially arranged; The electromagnetic control mechanism pushes the needle valve (6) to move toward one end of the mixing chamber (1012) of the ejector body assembly according to the change of the fuel cell load current. During the movement of the needle valve (6), the needle valve spring (7) and the sliding nozzle spring (8) are compressed at the same time. When the sliding nozzle (9) approaches the mixing chamber (1012) of the ejector body assembly, the needle valve (6) moves relative to the sliding nozzle (9) to change the cross-sectional area of ​​the channel between the needle valve (6) and the sliding nozzle (9).

2. A high-power composite adjustable hydrogen recirculation ejector device according to claim 1, characterized in that: The outer edges of the second annular baffle (603), the third annular baffle (901) and the first annular baffle are all supported on the inner wall of the main channel of the fixed nozzle (2), and the second annular baffle (603) is provided with a needle valve hole (602).

3. A high-power composite adjustable hydrogen recirculation ejector device according to claim 2, characterized in that: The needle valve holes (602) are provided in plurality and are arranged around the second annular baffle (603).

4. A high-power composite adjustable hydrogen recirculation ejector device according to claim 1, characterized in that: The ejector body assembly comprises an ejector body (1010), a primary flow tube (1014), a secondary flow tube (1005) and a mixing outlet tube (1009); the ejector body (1010) is provided with a primary flow receiving chamber (1003), a mixed flow receiving chamber (1013), a mixing chamber (1012) and a diffusion chamber (1011) in sequence; the primary flow tube (1014), the secondary flow tube (1005) and the mixing outlet tube (1009) are all connected to the ejector body (1010); the primary flow tube (1014) is connected to the secondary flow tube (1005) and the mixing outlet tube (1009) is connected to the primary flow tube (101 4) is connected to the primary flow receiving chamber (1003) through the primary air inlet channel (1002), the secondary flow pipe (1005) is connected to the mixed flow receiving chamber (1013), the mixed outlet pipe (1009) is connected to the output side of the diffusion chamber (1011), and the secondary flow pipe (1005) and the mixed outlet pipe (1009) are arranged on the same side, the primary flow pipe (1014) is located on the opposite side of the secondary flow pipe (1005), and the fixed nozzle (2) is located in the primary flow receiving chamber (1003) and the mixed flow receiving chamber (1013).

5. A high-power composite adjustable hydrogen recirculation ejector device according to claim 4, characterized in that: The secondary flow tube (1005) is fixed to the ejector body (1010) via a secondary flow tube screw (1004), and the mixing outlet tube (1009) is fixed to the ejector body (1010) via a mixing outlet tube screw (1007).

6. A high-power composite adjustable hydrogen recirculation ejector device according to claim 4, characterized in that: The inlet of the primary flow tube (1014) serves as the primary flow inlet (5), the inlet of the secondary flow tube (1005) serves as the secondary flow inlet (3), and the outlet of the mixing outlet tube (1009) serves as the mixing flow outlet (4).

7. A high-power composite adjustable hydrogen recirculation ejector device according to claim 1, characterized in that: The electromagnetic control mechanism comprises an electromagnetic shell (101), an end cover (104), and a coil (102), a guide sleeve (103), an armature (109) and an armature spring (110) arranged in the electromagnetic shell (101); the coil (102) is sleeved on the outside of the armature (109); a first section of the armature (109) is provided with a protruding column, the diameter of the protruding column is smaller than the support of the main part of the armature (109); the main part of the protruding column armature (109) forms a supporting step surface; one end of the armature spring (110) is supported on the supporting step surface, and the other end is supported on the inner wall of the electromagnetic shell (101); the end cover (104) is fixed to the main channel entrance of the fixed nozzle (2); the armature (109) is connected to the head end of the needle valve (6); and the needle valve rod (601) of the needle valve (6) passes through the end cover (104); When the load current of the fuel cell system is at a maximum, the current in the coil (102) is at a maximum, the electromagnetic force between the armature (109) and the electromagnet housing (101) is at a maximum, the armature spring (110) is subjected to a maximum force, and the armature 109 drives the needle valve (6) away from the sliding nozzle (9) to increase the cross-sectional area of ​​the sliding nozzle outlet (904) and to increase the distance between the sliding nozzle (9) and the mixing chamber (1012). When the load current is at a minimum, the electromagnetic force between the armature (109) and the electromagnet housing (101) is at a maximum and at a minimum, the armature spring (110) is subjected to a minimum force, and the armature (109) drives the needle valve (6) close to the sliding nozzle (9) to reduce the cross-sectional area of ​​the sliding nozzle outlet (904) and to reduce the distance between the sliding nozzle (9) and the mixing chamber (1012).

8. A high-power composite adjustable hydrogen recirculation ejector device according to claim 1, characterized in that: The sliding nozzle (9) also includes a primary flow equal area chamber (902), a primary flow convergence chamber (903) and a sliding nozzle outlet (904). The primary flow equal area chamber (902) and the primary flow convergence chamber (903) are arranged along the air flow direction. The primary flow equal area chamber (902) and the primary flow convergence chamber (903) are continuous buffer zones for the primary flow to prevent air flow shock caused by sudden changes in the cross section. The sliding nozzle outlet (904) is connected to the mixed flow receiving chamber (1013).

9. A high-power composite adjustable hydrogen recirculation ejector device according to claim 1, characterized in that: The fixed nozzle (2) comprises an end cover mounting ring and a nozzle body which are axially connected. The end cover mounting ring is provided with a countersunk hole (203) for connecting to an ejector body (1010) and a screw hole (204) for connecting to an electromagnetic control mechanism. The nozzle body is provided with a primary flow channel (201), and the internal main channel serves as a sliding area (202). The needle valve (6) and the sliding nozzle (9) are both clearance-matched with the sliding area (202) in the fixed nozzle (2).

10. A high-power composite adjustable hydrogen recirculation ejector device according to claim 1, characterized in that: The end of the needle valve (6) is in a cone shape.

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