An adjustable throat nozzle and pipeline natural gas hydrogen blending device for gas entrainment blending

Abstract

The application discloses a kind of adjustable throat nozzle for gas injection mixing and pipeline natural gas hydrogen mixing device, belong to gas mixing equipment technical field, the nozzle includes nozzle main body, multiple circumferential arrangement and form conical throat enclosed telescopic plate, axial slidingly set in the fixed ring of telescopic plate outside and with the drive assembly of fixed ring connection, elastic sealing element is arranged between telescopic plate, fixed ring is axially moved by drive assembly, utilize mechanical linkage to make each telescopic plate synchronous radial telescopic, to adjust nozzle throat flow area continuously, accurately, the nozzle is used as injector core, and with gas inlet unit, static mixing unit and metering unit integration, form pipeline natural gas hydrogen mixing device, the scheme is realized proportioning by pure mechanical structure, saves hydrogen compressor and complex electric control system, with Compact structure, intrinsic safety, low cost, high reliability advantage, especially suitable for hydrogenation station and other fixed hydrogenation scene.

Description

Technical Field

[0001] This invention relates to the field of gas ejector mixing technology, and more particularly to an adjustable throat nozzle for gas ejector mixing and a pipeline natural gas hydrogen blending device. Background Technology

[0002] In industrial practice, achieving safe and efficient mixing of natural gas and hydrogen faces multiple challenges. Existing technologies primarily rely on two mixing strategies: one is an independent flow control system, which mechanically mixes high-pressure natural gas and low-pressure hydrogen by separately metering their flow rates. This method requires complex sensor networks and real-time control algorithms, resulting in high system costs, slow response times, and difficulty maintaining a stable blending ratio under dynamic conditions. The other is an automatic blending method driven by the ejector principle, which uses the negative pressure generated by high-pressure natural gas flowing through a nozzle to eject low-pressure hydrogen. However, traditional ejectors generally employ a fixed throat structure with immutable geometry, leading to a fixed blending ratio that cannot adapt to fluctuations in pipeline pressure, changes in flow rate, or the flexible needs of different application scenarios. For example, when the natural gas pipeline load changes abruptly, the hydrogen blending ratio output by a fixed-throat ejector is prone to significant deviation, potentially causing combustion instability or equipment safety hazards.

[0003] To address adjustable requirements, some improved ejectors attempt to incorporate mechanical adjustment mechanisms, such as multi-stage valve control systems or external drive devices. However, such designs are often structurally redundant, containing numerous moving parts and connection interfaces. This not only results in large space requirements and complex installation but also poses reliability risks in high-pressure, flammable environments. During gas mixing, frequent mechanical adjustments can lead to wear at the throat sealing interface, creating minute gaps. Especially in the environment of small-molecule gases like hydrogen, the risk of leakage increases dramatically, potentially igniting an explosion. Furthermore, the lack of a predictable linear correlation between the displacement of the adjustment mechanism and changes in the throat flow cross-section makes it difficult for operators to accurately control the hydrogen blending ratio based on intuitive parameters, often requiring repeated trial and error adjustments, resulting in low efficiency and insufficient precision. In specific applications of natural gas blending with hydrogen, low-pressure hydrogen needs to be stably injected into high-pressure natural gas pipelines, placing stringent requirements on the ejector's dynamic response speed, sealing integrity, and repeatability of dimensional adjustments. Existing technologies exhibit large fluctuations in blending ratios under fluctuating flow conditions, failing to meet the precise hydrogen concentration control requirements of industrial combustion and fuel cell gas supply scenarios, thus hindering the promotion and application of natural gas blending technology. Summary of the Invention

[0004] The purpose of this invention is to provide an adjustable throat nozzle for gas ejection and a pipeline natural gas hydrogen blending device.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: an adjustable throat nozzle for gas ejection and mixing, comprising:

[0006] The nozzle body is equipped with at least two circumferentially arranged telescopic plates that surround and form a nozzle throat. The nozzle throat formed by the telescopic plates is conical. One end of each telescopic plate is rotatably connected to the nozzle body. The end of each telescopic plate away from the rotatable connection has a movable and variable diameter flow section. An elastic seal is provided between each telescopic plate.

[0007] A fixed ring is axially slidably fitted onto the outer side formed by the enclosing of each telescopic plate;

[0008] A drive assembly, connected to a retaining ring, is used to drive the retaining ring to move axially along the nozzle throat.

[0009] When the drive assembly drives the fixed ring to move away from the flow section, the fixed ring drives each telescopic plate to contract in the direction of the central axis of the nozzle throat, thereby reducing the flow section of the nozzle throat; when the drive assembly drives the fixed ring to move in the direction of the flow section, the elastic seal drives each telescopic plate to move away from the central axis of the nozzle throat through elastic deformation, thereby increasing the flow section of the nozzle throat.

[0010] By adopting the above technical solution, the adjustable throat nozzle uses a core flow channel formed by multiple circumferentially arranged telescopic plates. A fixed ring that can slide axially cooperates with the drive assembly to drive the radial movement of the telescopic plates. This design achieves mechanical stepless continuous adjustment of the flow cross-sectional area of ​​the nozzle throat. The adjustment process is completed entirely through precise mechanical transmission, eliminating the need for any electrical components or complex seals inside the high-temperature, high-pressure, flammable, and explosive flow channel. This significantly improves the inherent safety and long-term operational reliability of the entire adjustment mechanism under harsh operating conditions. At the same time, the elastic seals between the telescopic plates can adaptively fill the gaps between the plates, ensuring the continuity and airtightness of the flow channel profile at any adjustment position. This effectively prevents high-pressure gas from leaking from the gaps between the plates, ensuring the stability and efficiency of the ejector flow field. In addition, the entire adjustment mechanism has a compact structure, with the driving force acting directly on the fixed ring. Through mechanical linkage, it is transformed into the synchronous and symmetrical movement of multiple telescopic plates, avoiding flow field distortion or local wear caused by asynchronous movements. This makes the control of flow rate and ratio more precise and stable, paving the way for subsequent precise closed-loop control of hydrogen doping ratio.

[0011] The invention is further configured such that: the telescopic plate includes an arc-shaped telescopic plate one and an arc-shaped telescopic plate two slidably sleeved within the arc-shaped telescopic plate one; both the arc-shaped telescopic plate one and the arc-shaped telescopic plate two are provided with a plurality of equal numbers of arc-shaped telescopic plates arranged in a staggered manner along the circumference to form a nozzle throat; the fixed ring is annular with a conical guide surface on its inner wall; and the outer side of the arc-shaped telescopic plate one is provided with a driven inclined surface that cooperates with the conical guide surface, so that when the fixed ring is axially moved by the controlled drive assembly, the radial telescopic movement of each telescopic plate is converted into synchronous telescopic movement through the cooperation of the conical guide surface and the driven inclined surface.

[0012] By adopting the above technical solution, the telescopic plates are specifically designed as two interlocking arc-shaped telescopic plates, one inner and one outer, and the inner wall of the fixed ring is provided with a conical guide surface that cooperates with the driven inclined surface on the outer side of the arc-shaped telescopic plate one. This ingenious structure efficiently and synchronously converts the linear axial displacement of the fixed ring output by the drive component into the radial contraction or expansion motion of all telescopic plates through the contact and sliding between the inclined surfaces. This achieves the conversion of linear drive to radial deformation motion, with high conversion efficiency, low mechanical loss, and fast response speed. More importantly, this interlocking layout of inner and outer plates allows the edges of adjacent plates to overlap or slide and cover each other. After working together with the elastic seal, it can maintain a good seal during a large range of diameter changes, solving the technical problem of leakage at the middle seam in traditional multi-lobed structures. Furthermore, the interlocking structure enhances the rigidity and stability of the overall throat structure, enabling it to withstand the high pressure difference and airflow scouring inside the ejector, extending its service life. This design is the key to achieving stable, reliable, and leak-free diameter change function.

[0013] The present invention is further configured such that the axial movement distance of the fixed ring is proportional to the change in the equivalent diameter of the flow section of the nozzle throat.

[0014] By adopting the above technical solution, a preset proportional relationship between the axial movement distance of the fixed ring and the change in the equivalent diameter of the nozzle throat flow section is established and utilized in advance. This transforms the adjustment of the key parameter of throat size from direct control of complex geometry to linear or calibrable control of a single axial displacement of the fixed ring, greatly simplifying the control model and drive logic. The control system only needs to accurately control the displacement of the drive component based on the detection results, and can indirectly and accurately set the throat diameter. This reduces the complexity of real-time calculation and excessive dependence on sensor accuracy, and improves the system response speed and control stability. This preset proportional relationship can be solidified through precision machining and calibration in the early stage, ensuring the consistency of the adjustment characteristics of each device, facilitating mass production and application, and providing an interface and bridge for seamlessly integrating mechanical adjustment mechanisms into automated control systems.

[0015] The invention is further configured such that: the elastic seal includes a sliding seal connected to both sides along the length of the first arc-shaped telescopic plate; the sliding seal has a sliding groove that cooperates with the second arc-shaped telescopic plate in a sealing sliding manner; when one end of the flow section of the first arc-shaped telescopic plate is controlled by the fixed ring to contract toward the central axis of the nozzle throat, the sliding seal drives one end of the flow section of the second arc-shaped telescopic plate to move synchronously toward the central axis of the nozzle throat, thereby causing the flow section of the nozzle throat to become smaller.

[0016] By adopting the above technical solution, the elastic seal is specifically a sliding seal connected to both sides along the length of the first arc-shaped telescopic plate, and a sliding groove is opened to cooperate with the second arc-shaped telescopic plate in sealing and sliding. This design integrates dynamic sealing function and mechanical guiding function. The sliding groove not only provides a precise track for the telescopic movement of the second arc-shaped telescopic plate, restricting its movement to only in a predetermined direction and ensuring the coordination of the diameter change of multiple plates, but more importantly, the sliding seal itself constitutes a sealing barrier. No matter what position the second arc-shaped telescopic plate is in in the sliding groove, its side always maintains close contact with the groove wall, effectively blocking the path that high-pressure gas may leak along the sliding surface between the plates. This active following sealing method, compared with static sealing gaskets, is more adaptable to frequent adjustment actions and long-term wear, ensuring the long-term effectiveness of the seal within the entire adjustment range, thereby ensuring that the core flow field parameters of the ejector are not disturbed by leakage, and maintaining the control accuracy of the hydrogen doping ratio.

[0017] The present invention is further configured such that: the elastic seal further includes a return spring, the return spring being disposed within the sliding groove and abutting against the arc-shaped telescopic plate.

[0018] When the first and second arc-shaped telescopic plates move synchronously toward the central axis of the nozzle throat, the first and second arc-shaped telescopic plates are positioned close to each other at one end of the flow section, which drives the return spring to be in a compressed state.

[0019] When the fixed ring moves toward one end of the flow section, the reset spring drives the arc-shaped telescopic plate one and the arc-shaped telescopic plate two to be positioned far apart from each other at one end of the flow section through elastic deformation, thereby increasing the flow section of the nozzle throat.

[0020] By adopting the above technical solution, a return spring is added inside the sliding groove, which abuts against the second arc-shaped telescopic plate. This design gives the nozzle throat the ability to automatically reset or open when the drive component loses its active contraction power. When the drive component moves the fixed ring in the direction that causes the throat to contract, the inner and outer plates overcome the elastic force of the return spring and move closer to each other. The spring is compressed and stores energy. When it is necessary to increase the throat diameter, the drive component only needs to release the tension on the fixed ring or apply a reverse thrust. At this time, the elastic force stored in the compressed return spring will be released, pushing the second arc-shaped telescopic plate to move outward along the sliding groove. Then, through structural linkage, the entire telescopic plate assembly expands. This not only reduces the continuous demand on the output force of the drive component and optimizes energy consumption, but more importantly, it provides a failure protection mechanism. In extreme cases, such as drive failure or power failure, the force of the return spring can make the throat tend to a safe opening, such as the maximum flow area, to avoid the risk of overpressure caused by complete blockage of the system, thus enhancing the safety redundancy of the system.

[0021] The invention is further configured such that: the nozzle throat formed by the arc-shaped telescopic plate one and the arc-shaped telescopic plate two is in the shape of a frustum, one end of each telescopic plate is rotatably connected to the nozzle body and is the lower bottom surface of the frustum of the nozzle throat, the flow section is the upper bottom surface of the frustum of the nozzle throat, and the area of ​​the lower bottom surface is greater than the area of ​​the upper bottom surface.

[0022] By adopting the above technical solution, the nozzle throat formed by the enclosing of each telescopic plate is specifically designed as a frustum-shaped body, with the connecting end being a lower base with a larger area and the flow section end being an upper base with a smaller area. This unique geometry allows the flow channel cross-section to continuously converge along the flow direction when high-pressure natural gas enters from the inlet adjustment chamber, perfectly meeting the streamline requirements for fluid acceleration. It can efficiently convert pressure energy into kinetic energy, forming a high-speed and stable jet, providing a sufficient power source for ejecting low-pressure hydrogen. The frustum-shaped structure also naturally forms the guiding basis for the radial extension and retraction of the telescopic plate, ensuring that the throat shape always remains a cone-shaped shape that is conducive to fluid acceleration during the diameter change process. This avoids flow field separation or additional turbulence caused by shape distortion, ensuring the stability and efficiency of ejection performance. This is the key geometric feature that enables this nozzle to serve as the core component of the ejector and exert high efficiency.

[0023] The present invention is further configured such that: the driving assembly includes a plurality of telescopic motors and a plurality of telescopic rods controlled by the movement of the telescopic motors, the telescopic rods being pivotally connected to the fixed rings, and the number of telescopic motors, the number of telescopic rods, and the number of arc-shaped telescopic plates are all equal.

[0024] By adopting the above technical solution, the drive component specifically uses several telescopic motors and telescopic rods driven by them, with the number of telescopic motors equal to that of the arc-shaped telescopic plate. The telescopic rods are pivotally connected to the fixed ring. This multi-point symmetrical drive layout ensures that the fixed ring is subjected to uniform force during axial movement, without skewing or jamming. This drives all telescopic plates to move completely synchronously, achieving a perfectly circular change in the throat cross-sectional area. This avoids the disruption of jet symmetry by non-circular flow channels and ensures the stability of the ejector flow field. At the same time, the independent drive of multiple motors can also serve as a redundant design. Even if a single motor fails, the remaining motors can still maintain basic control over the fixed ring, improving the reliability of the system. The pivotal connection method allows for a certain degree of angular freedom between the telescopic rods and the fixed ring, compensating for minor errors that may exist in processing and assembly, and ensuring smooth transmission of driving force.

[0025] The present invention is further configured as: a pipeline natural gas hydrogen blending device, comprising: an adjustable throat nozzle;

[0026] An intake adjustment chamber, wherein the adjustable throat nozzle is installed inside the intake adjustment chamber;

[0027] The air intake chamber is arranged opposite to the flow section of the adjustable throat nozzle, and the side wall of the air intake chamber is provided with an inlet for the ejected fluid.

[0028] The mixing chamber, whose inlet is connected to the suction chamber, is used to mix the gas entering the ejector chamber with the gas being drawn into the suction chamber.

[0029] The diffusion chamber is located downstream of the mixing chamber and is shaped like a frustum of a cone.

[0030] By adopting the above technical solution, the aforementioned adjustable throat nozzle is specifically applied to a pipeline natural gas hydrogen blending device, and its integration relationship with the inlet adjustment chamber, intake chamber, mixing chamber, and diffusion chamber is clarified. This solution places the adjustable throat nozzle at the core power position of the ejector, so that its adjustment function directly acts on the initial kinetic energy of the ejector flow field, thereby achieving precise control of the ejected hydrogen volume. The integrated device has a compact structure and clear functions. Each chamber works in concert to complete the entire process from natural gas pressurization and acceleration, hydrogen ejection, two-phase mixing to pressure recovery. Moreover, the core adjustment variable of this process is reflected only by the diameter of a single mechanical component, namely the throat nozzle, making the entire hydrogen blending ratio control system exceptionally simple and efficient.

[0031] The present invention is further configured such that: the air intake adjustment chamber is connected to a high-pressure natural gas pipeline, the inlet of the ejected fluid is connected to a low-pressure hydrogen pipeline, and a check valve and a pressure reducing valve are sequentially provided on the low-pressure hydrogen pipeline along the airflow direction.

[0032] By adopting the above technical solution, the pipeline configuration of the gas inlet unit is clearly defined at the device level. In particular, check valves and pressure reducing valves are installed sequentially on the low-pressure hydrogen pipeline. This provides dual key safety and stability guarantees for the entire hydrogen blending system. The pressure reducing valve stabilizes the potentially fluctuating hydrogen pressure from the storage tank at a set low pressure value, providing a stable gas intake condition for the ejector. This is an important prerequisite for the stable operation of the ejector and the establishment of the hydrogen blending ratio formula. The check valve physically blocks the possibility of high-pressure natural gas or mixed gas flowing back into the low-pressure hydrogen storage tank under any circumstances, eliminating safety hazards. The combination of the two enables the hydrogen blending device based on the ejector principle to achieve high efficiency while possessing the reliability and safety foundation necessary for industrial applications.

[0033] The present invention is further configured such that: a mixing plate for fully mixing the gas is provided inside the diffusion cavity, the mixing plate being in the shape of a spiral blade or a porous plate disposed on the inner wall of the diffusion cavity.

[0034] By adopting the above technical solution, a spiral blade-shaped or porous plate-shaped mixing plate is set in the diffusion cavity. This is equivalent to adding a passive and efficient mixing enhancement stage after the ejector mixing unit. After the gas initially mixed by the ejector enters the diffusion cavity, the flow rate decreases and the pressure recovers. At this time, the fixedly installed mixing plate cuts, divides and redirects the fluid. It can achieve strong turbulent mixing at the microscale through the kinetic energy of the fluid itself without consuming additional energy. This ensures that hydrogen and natural gas achieve sufficient molecular-level homogeneity before entering the downstream pipeline network, avoiding combustion instability or detection errors caused by uneven mixing. This design is simple and reliable, has no moving parts, and has good durability.

[0035] This invention, by employing the above technical solutions, achieves significant technical effects: It features a highly reliable, precisely controllable, and intrinsically safe mechanically adjustable throat nozzle and its application in hydrogen blending devices. From the core variable-diameter mechanism composed of a telescopic plate, a fixed ring, and a drive assembly, to the elastic seals and springs ensuring sealing and reset, and the frustum-shaped design optimizing the flow field, each feature provides a mechanical solution to the pain points of high energy consumption, poor reliability, and complex control in existing technologies. Integrating these components into a complete ejector blending device, supplemented by key units such as pressure reducing valves, check valves, and static mixers, ultimately forms an integrated device that achieves automatic low-pressure hydrogen ejection, blending at fixed or adjustable ratios, pressurization, homogenization, and metering without the need for an external hydrogen compressor, relying solely on fluid dynamics principles and mechanical adjustment. This device significantly simplifies the structure, reduces costs, eliminates the risks of electronic control in hazardous environments, and achieves safe, efficient, and reliable operation, providing a technical equipment foundation for the large-scale and safe application of hydrogen blending technology in natural gas pipelines. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the adjustable throat nozzle structure within the pipeline natural gas hydrogen blending device in the embodiment.

[0037] Figure 2 This is a schematic diagram of the nozzle throat in the embodiment;

[0038] Figure 3 This is a schematic diagram of the return spring in a compressed state in the embodiment;

[0039] Figure 4 This is a schematic diagram in the embodiment where the reset spring drives the adjacent telescopic plates to move away from each other.

[0040] The parts referred to by the numbers in the above attached figures are as follows: 1. Nozzle body; 2. Telescopic plate; 201. Arc-shaped telescopic plate one; 202. Arc-shaped telescopic plate two; 3. Nozzle throat; 31. Flow section; 4. Fixing ring; 5. Drive assembly; 501. Telescopic motor; 502. Telescopic rod; 6. Elastic seal; 601. Sliding seal; 602. Return spring; 7. Inlet adjustment chamber; 8. Intake chamber; 9. Mixing chamber; 10. Diffusion chamber; 11. Inlet of injected fluid; 12. Mixing plate; 13. High-pressure natural gas pipeline. Detailed Implementation

[0041] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0042] Example 1:

[0043] Traditional ejectors for blending hydrogen into natural gas suffer from several drawbacks. These include a fixed throat structure that prevents dynamic adjustment of the blending ratio, complex and bulky adjustable structures, low adjustment precision, and slow response. In high-pressure, flammable, and explosive environments, existing variable throat designs also suffer from poor sealing, severe wear, and leakage risks. Furthermore, the lack of a precise linear relationship between the adjustment mechanism and the throat dimensions makes it difficult to achieve accurate proportional control and meet the stable blending requirements under fluctuating flow conditions.

[0044] In response, this application proposes an adjustable throat nozzle for gas ejection and mixing. The nozzle includes a nozzle body 1, with at least two circumferentially arranged telescopic plates 2 forming a nozzle throat 3. The nozzle throat 3 formed by the telescopic plates 2 is conical. One end of each telescopic plate 2 is rotatably connected to the nozzle body 1. The end of each telescopic plate 2 away from the rotatably connected end has a movable, variable-diameter flow section 31. An elastic seal 6 is provided between each telescopic plate 2. The nozzle also includes a retaining ring 4, which is axially slidably fitted onto the outer surface formed by the telescopic plates 2. A drive assembly 5 is connected to... The fixing ring 4 is connected and used to drive the fixing ring 4 to move axially along the nozzle throat 3. When the drive assembly 5 drives the fixing ring 4 to move away from the flow section 31, the fixing ring 4 drives each telescopic plate 2 to contract in the direction of the central axis of the nozzle throat 3, thereby reducing the flow section 31 of the nozzle throat 3. When the drive assembly 5 drives the fixing ring 4 to move towards the end of the flow section 31, the elastic seal 6 drives each telescopic plate 2 to move away from the central axis of the nozzle throat 3 through elastic deformation, thereby increasing the flow section 31 of the nozzle throat 3.

[0045] This application provides an adjustable throat nozzle for gas ejection mixing. The nozzle body 1 serves as the support structure for the entire device. Inside the nozzle body 1, at least two telescopic plates 2 are arranged. The telescopic plates 2 are evenly arranged circumferentially and together enclose the nozzle throat 3. The size of the throat is changed by its radial movement. The nozzle throat 3 formed by the telescopic plates 2 is conical. The inner surface of the telescopic plates 2 can be designed as a plane or a curved surface, so that the throat formed by them has a gradually contracting or expanding geometry in the axial direction to guide the airflow.

[0046] One end of each telescopic plate 2 is rotatably connected to the nozzle body 1. This rotatable connection can be a pin connection, a hinge connection, or other connection methods that enable rotation, so that the telescopic plate 2 can swing around the connection point as a fulcrum, thereby changing the radial dimension of the throat at the other end of the telescopic plate 2. The end of each telescopic plate 2 away from the rotatable connection forms a movable and variable diameter flow section 31. This flow section 31 is the area through which the gas actually flows, and its diameter or area can be adjusted as needed. For example, the free end of the telescopic plate 2 can be designed with a straight or curved edge, and the size of the flow section 31 can be changed by its radial movement.

[0047] To ensure the sealing of the nozzle throat 3 during the movement of the telescopic plates 2, an elastic seal 6 is provided between each telescopic plate 2. The elastic seal 6 can be made of rubber strips, silicone strips, or other elastic materials and is filled in the gap between adjacent telescopic plates 2. It provides a sealing effect when the telescopic plates 2 move and can provide a certain degree of restoring force. A fixing ring 4 is axially slidably fitted on the outer side formed by the enclosing of each telescopic plate 2. The fixing ring 4 can be an annular sleeve, with its inner wall in contact with the outer side of the telescopic plate 2. When the fixing ring 4 moves axially, the interaction between its inner wall and the outer side of the telescopic plate 2 can push or allow the telescopic plate 2 to move radially. The inner wall of the fixing ring 4 transmits axial force through friction or simple point-line-surface contact. The drive assembly 5 is connected to the fixing ring 4 and is used to drive the fixing ring 4 to move axially along the nozzle throat 3. The drive assembly 5 can be a simple push rod mechanism, such as a manual screw or cylinder, to push the fixing ring 4 to move axially.

[0048] When the drive assembly 5 drives the fixed ring 4 to move away from the flow section 31, the fixed ring 4 will cause each telescopic plate 2 to contract towards the central axis of the nozzle throat 3, thereby reducing the flow section 31 of the nozzle throat 3. Specifically, the axial movement of the fixed ring 4 will convert the axial force into a radial force through its contact surface with the telescopic plate 2, forcing the telescopic plate 2 to swing or slide inward. Conversely, when the drive assembly 5 drives the fixed ring 4 to move towards the flow section 31, the elastic seal 6 will cause each telescopic plate 2 to move away from the central axis of the nozzle throat 3 through elastic deformation, thereby increasing the flow section 31 of the nozzle throat 3. For example, when the fixed ring 4 moves towards the flow section 31, the radial constraint on the telescopic plate 2 decreases. At this time, the elastic restoring force of the elastic seal 6 will push the telescopic plate 2 to open outward, thereby increasing the flow section 31.

[0049] The adjustable throat nozzle of this application forms a conical throat by means of a telescopic plate 2, and the flow section 31 of the throat is precisely and dynamically adjusted by means of a fixed ring 4 and a drive assembly 5. This structure simplifies the adjustment mechanism, avoids the complexity of traditional multi-stage valve control systems, and improves the adjustment response speed. At the same time, the setting of the elastic seal 6 effectively solves the problem of poor sealing and leakage risk in high-pressure gas mixing environment. This design allows the size of the nozzle throat 3 to be flexibly adjusted according to the working conditions, thereby achieving stable control of the natural gas hydrogen blending ratio and meeting the blending requirements under different flow fluctuations.

[0050] The adjustable throat nozzle proposed in this application has a flow section 31 of the nozzle throat 3 that is adjusted by the radial movement of the telescopic plate 2. However, in actual operation, how to ensure that multiple telescopic plates 2 can achieve precise, synchronous, and stable radial telescopic movement during the adjustment process, so as to ensure the stability of the cross-sectional shape of the nozzle throat 3 and the reliability of the adjustment, is a technical problem that needs to be solved. Especially when it is necessary to finely control the size of the flow section 31 to adapt to different working conditions, higher requirements are placed on the synchronicity and accuracy of the movement of the telescopic plates 2. In order to solve the above problems, this application further proposes that the telescopic plate 2 of the above-mentioned adjustable throat nozzle includes an arc-shaped telescopic plate 201 and an arc-shaped telescopic plate 202 slidably sleeved in the arc-shaped telescopic plate 201. The arc-shaped telescopic plate 201 and the arc-shaped telescopic plate 202 are provided in several equal numbers and are arranged alternately along the circumference to jointly enclose the nozzle throat 3. This nested arc-shaped telescopic plate 2 structure The structure ensures that the telescopic plate 2 maintains good guidance and stability during radial movement. The arc-shaped telescopic plate 201 serves as an external support, and the arc-shaped telescopic plate 202 serves as an internal sliding component. The sliding cooperation between the two ensures the compactness of the overall structure and the smoothness of movement. For example, three or four nested pairs of arc-shaped telescopic plates 201 and 202 can be set and evenly distributed along the circumference of the nozzle throat 3 to form an approximately circular flow section 31. At the same time, the fixing ring 4 is annular, and its inner wall is provided with a conical guide surface. This conical guide surface is the key structure for realizing the conversion from axial movement to radial movement. The angle of the conical guide surface can be designed according to the required radial adjustment range and axial drive stroke to achieve the best conversion efficiency and adjustment accuracy. For example, by selecting an appropriate cone angle, a larger radial adjustment can be achieved with a smaller axial movement distance, or a finer radial adjustment can be achieved with a larger axial movement distance.

[0051] In conjunction with the tapered guide surface of the fixed ring 4, the outer side of the arc-shaped telescopic plate 201 is provided with a driven inclined surface. This driven inclined surface forms mechanical contact with the tapered guide surface of the fixed ring 4, together forming an inclined transmission mechanism. The angle of the driven inclined surface matches the tapered guide surface to ensure that when the fixed ring 4 moves axially, the axial force can be smoothly and effectively decomposed into radial force, thereby driving the arc-shaped telescopic plate 201 to move radially, and then synchronously driving the arc-shaped telescopic plate 202 to move radially. The driven inclined surface can be integrally formed on the side wall of the arc-shaped telescopic plate 201, or it can be a component that is separately processed and fixed on the arc-shaped telescopic plate 201. Its surface can be hardened or coated with anti-friction material to improve wear resistance and reduce frictional resistance.

[0052] Through the cooperation of the tapered guide surface and the driven inclined surface, when the fixed ring 4 is controlled by the drive assembly 5 to move axially, its axial movement can be accurately converted into the synchronous radial extension and retraction movement of each telescopic plate 2. This mechanical linkage method ensures that all telescopic plates 2 move synchronously in the radial direction with the same speed and displacement.

[0053] Through the above technical solution, this application introduces a nested structure of arc-shaped telescopic plate 1 201 and arc-shaped telescopic plate 202. By utilizing the conical guide surface of the inner wall of the fixing ring 4 in conjunction with the driven inclined surface of the outer side of the arc-shaped telescopic plate 1 201, the axial movement of the drive component 5 can be accurately converted into the synchronous radial telescopic movement of each telescopic plate 2. This design effectively solves the technical problem that it is difficult to achieve precise, synchronous and stable radial movement of multiple telescopic plates 2 during the adjustment process. Specifically, the annular fixing ring 4, through its conical guide surface, can simultaneously and uniformly act on the driven inclined surface of all arc-shaped telescopic plates 1 201, thereby ensuring that all telescopic plates 2 move synchronously in the radial direction with the same speed and displacement. This avoids the distortion of the cross-sectional shape of the nozzle throat 3 or the instability of the adjustment caused by the asynchronous movement of each telescopic plate 2. In addition, the nested arc-shaped telescopic plate 2 structure also provides a more stable guide for the radial movement, further improving the stability and reliability of the adjustment, so that the flow section 31 of the nozzle throat 3 can be precisely and repeatably adjusted, thereby optimizing the efficiency and stability of gas ejection mixing.

[0054] In some embodiments of this application, the fixed ring 4 is driven to move axially by the drive component 5, and the radial extension and retraction of each extension plate 2 is realized by the cooperation between the conical guide surface of the inner wall of the fixed ring 4 and the driven inclined surface of the outer side of the arc-shaped telescopic plate 201, thereby changing the flow section 31 of the nozzle throat 3. However, in practical applications, if there is no clear and quantifiable correspondence between the axial movement distance of the fixed ring 4 and the change in the flow section 31 of the nozzle throat 3, it is difficult to achieve precise and controllable adjustment of the flow section 31 of the nozzle throat 3, which may lead to insufficient adjustment accuracy and affect the stability of gas mixing.

[0055] In this regard, this application further proposes that the axial movement distance of the fixed ring 4 is proportional to the change in the equivalent diameter of the flow section 31 of the nozzle throat 3. Specifically, the axial movement distance of the fixed ring 4 refers to the displacement by which the driving component 5 drives the fixed ring 4 to move along the axial direction of the nozzle throat 3. This displacement is a direct input parameter for adjusting the flow section 31 of the nozzle throat 3. The change in the equivalent diameter of the flow section 31 of the nozzle throat 3 refers to the degree of change in the effective diameter of the flow section 31 of the nozzle throat 3 during the adjustment process. Since the nozzle throat 3 may be formed by multiple telescopic plates 2, its cross-sectional shape may not be strictly circular. Therefore, using the equivalent diameter to characterize its dimensional change can more accurately reflect the fluid. The pre-defined proportional relationship refers to a predetermined and quantifiable mathematical correspondence between the axial movement distance of the fixed ring 4 and the equivalent diameter change of the flow section 31 of the nozzle throat 3. This proportional relationship can be achieved through precise mechanical design. For example, by optimizing the angle between the tapered guide surface of the inner wall of the fixed ring 4 and the driven inclined surface of the outer side of the arc-shaped telescopic plate 201, the axial displacement of the fixed ring 4 can be linearly converted into the radial displacement of the telescopic plate 2, thereby linearly changing the equivalent diameter of the nozzle throat 3. In addition, this proportional relationship can also be preset through system calibration, table lookup, or control algorithm to ensure that a stable proportional relationship is maintained between the input and output throughout the entire adjustment range.

[0056] Through the above technical solution, this application can achieve precise and linear adjustment of the flow section 31 of the nozzle throat 3. This means that the operator or control system can directly calculate the required axial movement distance of the fixed ring 4 according to the expected flow or pressure requirements, thereby avoiding a complex trial-and-error or repeated calibration process. This predictable adjustment mechanism significantly improves the accuracy and response speed of the nozzle throat 3 adjustment, ensuring the stability and efficiency of the gas ejection and mixing process. Its advantages are even more obvious in application scenarios that require frequent or fine adjustment of the flow section 31.

[0057] In some embodiments described above in this application, a nozzle throat 3 is formed by alternating arc-shaped telescopic plates 201 and 202, and the radial telescopic movement of each telescopic plate 2 is achieved by the axial movement of the fixing ring 4. However, achieving an effective and synchronous seal between the arc-shaped telescopic plates 201 and 202 to ensure that gas does not leak during the change of the flow section 31 of the nozzle throat 3 and to ensure coordinated movement of each telescopic plate 2 is a technical problem that needs to be solved.

[0058] In response, this application further proposes an elastic seal 6 including a sliding seal 601 and a return spring 602 connected to both sides along the length of the arc-shaped telescopic plate 201. The sliding seal 601 has a sliding groove that slides and seals with the arc-shaped telescopic plate 202. When one end of the flow section 31 of the arc-shaped telescopic plate 201 is controlled by the fixing ring 4 to contract towards the central axis of the nozzle throat 3, the sliding seal 601 drives one end of the flow section 31 of the arc-shaped telescopic plate 202 to move synchronously towards the central axis of the nozzle throat 3, causing the flow section 31 of the nozzle throat 3 to become smaller. The return spring 602 is provided with... The device is placed in the sliding groove and abuts against the arc-shaped telescopic plate 202. When the arc-shaped telescopic plate 201 and the arc-shaped telescopic plate 202 move synchronously toward the central axis of the nozzle throat 3, the arc-shaped telescopic plate 201 and the arc-shaped telescopic plate 202 are positioned close to each other at one end of the flow section 31, causing the return spring 602 to be compressed. When the fixed ring 4 moves toward one end of the flow section 31, the return spring 602, through elastic deformation, causes the arc-shaped telescopic plate 201 and the arc-shaped telescopic plate 202 to be positioned far apart from each other at one end of the flow section 31, causing the flow section 31 of the nozzle throat 3 to increase.

[0059] The return spring 602 can be a helical compression spring. Its main function is to provide an active outward pushing force for the arc-shaped telescopic plate 202, so as to ensure that the nozzle throat 3 can reliably and quickly expand when the flow cross section 31 needs to be increased. Setting the return spring 602 in the sliding groove and abutting against the arc-shaped telescopic plate 202 means that the return spring 602 is precisely positioned in the sliding fit area between the arc-shaped telescopic plate 1 201 and the arc-shaped telescopic plate 202. This setting ensures that the force of the return spring 602 can directly and effectively act on the arc-shaped telescopic plate 202, so that it can be passively compressed when the fixed ring 4 moves, and actively pushed outward by the elastic restoring force of the spring when the fixed ring 4 moves in the opposite direction. This structural design helps to maintain the stable working state of the spring, prevent it from deflecting or jamming during the movement, and optimize the force transmission path.

[0060] The sliding seal 601 is a device that allows relative movement between two components while maintaining a seal. It is typically made of a material with a certain degree of elasticity and wear resistance, such as rubber. In this embodiment, the sliding seal 601 is designed to connect to both sides along the length of the arc-shaped telescopic plate 201. This means that it forms an integral part with the arc-shaped telescopic plate 201 and provides a sliding interface for the arc-shaped telescopic plate 202. This connection method ensures the relative fixation of the seal and the arc-shaped telescopic plate 201, thereby providing stable sealing support when the arc-shaped telescopic plate 202 slides. This can be achieved by fixing the sliding seal 601 to the side of the arc-shaped telescopic plate 201 by means of bonding, snap-fitting, bolting, etc.

[0061] The sliding seal 601 is specially designed with a sliding groove whose shape and size match the outline of the arc-shaped telescopic plate 202, allowing the arc-shaped telescopic plate 202 to slide smoothly and securely within the groove. The sliding groove provides a precise guiding and sealing interface for the arc-shaped telescopic plate 202. When the arc-shaped telescopic plate 202 moves in the radial direction, it slides within the sliding groove. Simultaneously, the elastic material of the sliding seal 601 closely adheres to the surface of the arc-shaped telescopic plate 202, thereby forming a dynamic seal and effectively preventing gas leakage. The inner wall of the sliding groove can be surface treated, such as polishing or coating with a low-friction coating, to reduce sliding resistance and improve the life of the seal. In addition, the cross-sectional shape of the sliding groove can be designed as a rectangle, dovetail groove, or other irregular shape according to the cross-sectional shape of the arc-shaped telescopic plate 202 to ensure optimal fit and sealing effect.

[0062] When the fixed ring 4 drives the arc-shaped telescopic plate 201 to move towards the central axis via the conical guide surface and the driven inclined surface, the sliding seal 601 is connected to the arc-shaped telescopic plate 201, and the arc-shaped telescopic plate 202 slides in the sliding groove of the sliding seal 601. The sliding seal 601 will directly or indirectly exert a force on the arc-shaped telescopic plate 202. Specifically, the structural design of the sliding seal 601 makes the arc-shaped telescopic plate 202 pushed or pulled in the sliding groove, so that it moves towards the central axis synchronously with the arc-shaped telescopic plate 201. This synchronous movement ensures that all telescopic plates 2 can change their positions in a coordinated manner during the contraction of the nozzle throat 3, thereby achieving a smooth and uniform reduction of the flow cross section 31 and maintaining good sealing performance, avoiding gaps or leaks caused by asynchronous movement.

[0063] Through the above technical solution, this application effectively solves the problem of synchronous movement and sealing between different telescopic plates 2 in a multi-plate telescopic plate 2 structure. The sliding seal 601, through its connection with the arc-shaped telescopic plate 1 201 and the sliding groove provided for the arc-shaped telescopic plate 202, can effectively drive the arc-shaped telescopic plate 202 to move synchronously towards the central axis when the fixed ring 4 drives the arc-shaped telescopic plate 1 201 to contract. This design ensures that the arc-shaped telescopic plate 1 201 and the arc-shaped telescopic plate 202 remain tightly and dynamically connected as the flow cross-section 31 of the nozzle throat 3 decreases. The sealing prevents gas leakage from the non-nozzle throat 3 positions of the arc-shaped telescopic plate 1 201 and arc-shaped telescopic plate 202. The sliding seal 601 not only provides a reliable gas seal to prevent fluid leakage during the adjustment process of the nozzle throat 3, but also ensures, through its structural design, that the arc-shaped telescopic plate 1 201 and arc-shaped telescopic plate 202 can achieve precise synchronous radial movement when contracting. This allows the flow section 31 of the nozzle throat 3 to decrease smoothly and uniformly, improving the accuracy and response speed of flow regulation, while enhancing the operational stability and reliability of the entire nozzle system.

[0064] In some embodiments of this application, the increase in the flow cross section 31 of the nozzle throat 3 mainly relies on the elastic deformation of the return spring 602 of the elastic seal 6 to drive each telescopic plate 2 to move away from the central axis of the nozzle throat 3. However, in practical applications, the elastic deformation capability of the elastic seal 6 may be affected by material fatigue, wear or external friction, resulting in insufficient or unstable return force, which may affect the reliability and response speed of the expansion of the flow cross section 31 of the nozzle throat 3. Especially in scenarios that require precise control or rapid adjustment, this method of relying on a single elastic deformation may not meet the high performance requirements.

[0065] When the fixed ring 4 moves to reduce the flow cross section 31, the arc-shaped telescopic plate 1 201 and the arc-shaped telescopic plate 202 contract inward synchronously. At this time, the return spring 602 is compressed and stores elastic potential energy. When it is necessary to increase the flow cross section 31, the fixed ring 4 moves in the opposite direction, and the return spring 602 releases its stored energy, actively and forcefully pushing the arc-shaped telescopic plate 202 outward. This causes the arc-shaped telescopic plate 1 201 and the arc-shaped telescopic plate 202 to be positioned far apart from each other at one end of the flow cross section 31. Compared with nozzles without springs, the return of the arc-shaped telescopic plate 1 201 and the arc-shaped telescopic plate 202 is driven by the pressure of natural gas, ensuring that the flow cross section 31 of the nozzle throat 3 can be reliably and quickly increased. This design effectively overcomes the problem of insufficient or unstable return force that may be caused by relying solely on the elastic deformation of the elastic seal 6. It significantly improves the response speed, accuracy and long-term stability of the nozzle throat 3 adjustment, enabling the adjustable throat nozzle to achieve more precise and reliable flow control during gas injection and mixing.

[0066] The nozzle throat 3 is described as conical; however, this generalized conical structure may not provide optimal fluid acceleration and mixing during gas ejection and mixing, especially in scenarios where precise flow field control is required to avoid fluid separation or turbulence loss. Its hydrodynamic performance may be limited. The nozzle throat 3 formed by the arc-shaped telescopic plate 1 201 and the arc-shaped telescopic plate 202 is truncated cone-shaped. One end of each telescopic plate 2 is rotatably connected to the nozzle body 1, which is the lower bottom surface of the truncated cone of the nozzle throat 3. The flow section 31 is the upper bottom surface of the truncated cone of the nozzle throat 3. The area of ​​the lower bottom surface is larger than that of the upper bottom surface. The cone shape can provide a smooth and gradually narrowing flow channel, which helps to guide the airflow, reduce fluid separation and eddy generation, thereby improving the acceleration efficiency and stability of the fluid. By precisely designing the angle and size of the truncated cone, the velocity distribution and pressure gradient of the fluid can be optimized, creating favorable conditions for the subsequent gas ejection and mixing process.

[0067] Each telescopic plate 2 is rotatably connected to the nozzle body 1 at one end, which is the lower bottom surface of the truncated cone of the nozzle throat 3. This clarifies that the larger diameter end of the truncated cone is located at the inlet of the nozzle throat 3, that is, on the side close to the nozzle body 1. This setting ensures that the airflow enters from a larger cross section and begins to gradually converge, providing initial conditions for the smooth acceleration of the airflow.

[0068] The flow section 31 is the upper bottom surface of the frustum of the nozzle throat 3. This indicates that the end of the frustum with the smaller diameter is the variable-diameter flow section 31, i.e., the outlet of the nozzle throat 3. This is the key area where the airflow reaches its maximum velocity and generates the ejection effect. By adjusting the size of this upper bottom surface, the flow area of ​​the nozzle throat 3 can be precisely controlled, thereby adjusting the flow rate and mixing ratio of the ejected gas. The area of ​​the lower bottom surface is larger than that of the upper bottom surface, which further clarifies that the nozzle throat 3 is a converging frustum. This converging structure is the physical basis for achieving airflow acceleration and pressure reduction. It ensures that the main airflow increases in velocity and decreases in static pressure when passing through the nozzle throat 3, thereby effectively ejecting the secondary gas.

[0069] The frustum shape effectively prevents fluid separation or unnecessary turbulence in the throat region, thus significantly reducing energy loss during fluid flow. When the drive assembly 5 drives the fixed ring 4 to move axially, the arc-shaped telescopic plate 1 201 and the arc-shaped telescopic plate 202 extend and retract radially in sync, always maintaining the frustum-shaped throat geometry. This ensures that the airflow can achieve smooth and efficient acceleration under different flow sections 31. This not only improves the acceleration efficiency of the main airflow, making it form a stronger and more stable low-pressure zone at the flow section 31, thereby enhancing the ejection effect, but also makes the gas mixing more uniform. The overall operating efficiency and stability of the device are significantly improved.

[0070] The drive assembly 5 drives the fixed ring 4 to move axially along the nozzle throat 3. The conical guide surface of the inner wall of the fixed ring 4 engages with the driven inclined surface of the outer side of the arc-shaped telescopic plate 201, thereby achieving radial telescopic movement of each telescopic plate 2 and adjusting the flow section 31 of the nozzle throat 3. However, in actual operation, if the drive assembly 5 fails to provide a uniform, synchronous, and stable driving force, the fixed ring 4 may tilt or jam during axial movement, affecting the synchronicity and accuracy of the radial movement of each telescopic plate 2. This could even cause deformation or uneven wear of the nozzle throat 3, reducing the reliability and service life of the nozzle adjustment. The drive assembly 5 includes several telescopic... The device consists of a telescopic motor 501 and several telescopic rods 502 controlled by the telescopic motor 501. The telescopic rods 502 are pivotally connected to the fixed ring 4. The number of telescopic motors 501, telescopic rods 502, and arc-shaped telescopic plates 201 and 202 are all equal. The telescopic motors 501, the telescopic rods 502 that cooperate with the telescopic motors 501, the arc-shaped telescopic plates 201 and 202 are all arranged in a circular array to prevent the fixed ring 4 from tilting or being unbalanced when moving axially. This ensures that the driving force can be applied to the fixed ring 4 evenly and symmetrically, guaranteeing the stability of the movement of the fixed ring 4 and the synchronicity of the radial movement of each arc-shaped telescopic plate 201.

[0071] This application also proposes a pipeline natural gas hydrogen blending device, which includes the aforementioned adjustable throat nozzle and is further configured with an inlet adjustment chamber 7, an intake chamber 8, a mixing chamber 9, and a diffusion chamber 10. The adjustable throat nozzle is installed in the inlet adjustment chamber 7, which is typically a cavity with sufficient volume. Its main function is to provide a stable and uniform flow field for the ejector fluid, such as high-pressure natural gas, entering the adjustable throat nozzle. By setting this cavity before the nozzle inlet, fluid disturbances and pressure fluctuations caused by the upstream pipeline can be effectively eliminated, ensuring that the fluid enters the nozzle in a stable state, thereby providing reliable initial conditions for the subsequent ejection and mixing processes.

[0072] The intake chamber 8 is positioned opposite to the flow section 31 of the adjustable throat nozzle, and its side wall is provided with an inlet 11 for the ejected fluid. The intake chamber 8 is a key component for gas ejection. The high-speed ejected fluid ejected through the adjustable throat nozzle forms a local low-pressure zone in the chamber, thereby drawing in the low-pressure hydrogen gas introduced by the inlet 11. The geometry and size design of the intake chamber 8 are crucial to the ejection efficiency. It is usually designed to maximize the ejection effect and guide the initial mixing of the two fluids. The inlet 11 for the ejected fluid is a channel for introducing the ejected fluid. It can be one or more openings or an annular slit. Its position and size should ensure that the ejected fluid can enter the intake chamber 8 uniformly and stably and make full contact with the ejected fluid.

[0073] The inlet of the mixing chamber 9 is connected to the intake chamber 8 and is used to mix the ejector fluid ejected through the adjustable throat nozzle with the gas drawn into the intake chamber 8. The mixing chamber 9 is located downstream of the intake chamber 8 and its main function is to provide sufficient mixing distance and space for the two gases to ensure that they can diffuse and mix fully to achieve the required mixing uniformity. The length and inner wall structure of the mixing chamber 9 can be optimized according to the required mixing effect. For example, a straight pipe section or a pipe section with a turbulence structure can be used.

[0074] The diffuser 10 is located downstream of the mixing chamber 9 and is shaped like a truncated cone. The function of the diffuser 10 is to decelerate the high-speed fluid after mixing and convert the kinetic energy of the fluid into static pressure energy, thereby achieving pressure recovery and reducing the energy loss of the entire device. Its truncated cone-shaped structural design allows the fluid cross-section to gradually expand and the flow velocity to gradually decrease, while avoiding fluid separation and ensuring efficient pressure recovery.

[0075] Through the above technical solution, this application provides a compact and fully functional pipeline natural gas hydrogen blending device. This device utilizes an adjustable throat nozzle to precisely control the flow rate and velocity of the main gas flow, thereby precisely controlling the ejection effect and blending ratio. The inlet adjustment chamber 7 ensures the stability of the main gas flow, while the suction chamber 8 and the ejected fluid inlet 11 efficiently draw in the ejected hydrogen gas for preliminary mixing. The mixing chamber 9 provides ample mixing space, ensuring highly uniform blending of the two gases. Finally, the diffusion chamber 10 effectively recovers the fluid pressure, significantly improving the system's operating efficiency and economy. Overall, this device can achieve precise proportional blending and efficient uniform mixing of different gases, while reducing operating energy consumption, providing a stable and reliable solution for applications such as pipeline natural gas hydrogen blending.

[0076] In response, this application proposes a pipeline natural gas hydrogen blending device, which achieves gas injection and blending through an adjustable throat nozzle. However, in practical applications, if the pressure characteristics of different gases are not effectively managed, especially when the blending gases are high-pressure natural gas and low-pressure hydrogen, problems such as gas backflow, large pressure fluctuations, unstable injection efficiency, and safety hazards may be encountered, thereby affecting the stability and reliability of the entire blending process.

[0077] To address the aforementioned issues, this application further proposes that the intake adjustment chamber 7 is connected to a high-pressure natural gas pipeline, and the ejected fluid inlet 11 is connected to a low-pressure hydrogen pipeline, with a check valve and a pressure reducing valve sequentially installed along the airflow direction on the low-pressure hydrogen pipeline.

[0078] Specifically, the intake adjustment chamber 7 is a chamber used to receive and initially adjust the main gas flow of natural gas. The high-pressure natural gas pipeline is a pipeline system specifically designed to transport high-pressure natural gas. It usually has a high pressure resistance rating and good sealing performance. By connecting the intake adjustment chamber 7 to the high-pressure natural gas pipeline, it can be ensured that the main gas flow of natural gas can enter the adjustable throat nozzle stably with sufficient pressure and flow, providing a sufficient power source for the subsequent injection process. This pipeline is usually equipped with corresponding pressure monitoring, flow control and emergency shut-off devices to achieve precise control and safety assurance of natural gas supply.

[0079] The inlet 11 is the interface connecting the intake chamber 8 to the external hydrogen fluid. The low-pressure hydrogen pipeline is a pipeline system used to transport low-pressure hydrogen. Its design needs to take into account the special properties of hydrogen, such as flammability, explosiveness, small molecules, and easy leakage. Therefore, high-sealing materials and connection methods are usually used. By connecting this inlet to the low-pressure hydrogen pipeline, it can be ensured that the hydrogen to be injected can be stably and safely introduced into the intake chamber 8, preparing for mixing with natural gas.

[0080] A check valve and a pressure reducing valve are sequentially installed along the gas flow direction on the low-pressure hydrogen pipeline. The check valve is a one-way valve whose core function is to allow the medium to flow only in a preset direction and prevent reverse flow. In this application, the check valve is installed on the low-pressure hydrogen pipeline. During the natural gas injection of hydrogen, if the natural gas pressure fluctuates or an abnormality occurs in the injection chamber, high-pressure natural gas may backflow into the low-pressure hydrogen pipeline. The check valve effectively prevents this backflow, thus avoiding the mixing of high-pressure natural gas and low-pressure hydrogen in unexpected areas, ensuring system operational safety, and preventing equipment damage or operational instability caused by pressure backflow. The pressure reducing valve is a valve that automatically reduces and stabilizes the pressure output. A pressure reducing valve, through an internal regulating mechanism, reduces the upstream high-pressure hydrogen to the lower and more stable pressure level required downstream. In gas ejector blending devices, hydrogen is typically supplied from a storage tank or source at a certain pressure, which may be higher than the optimal pressure required for the ejection process. The function of the pressure reducing valve is to precisely adjust the hydrogen pressure to a suitable low-pressure level for ejection, ensuring the stability and efficiency of the ejection process. A stable low-pressure hydrogen supply helps the adjustable throat nozzle achieve precise blending ratio control, while also protecting downstream low-pressure equipment from high-pressure shocks and extending equipment lifespan. Pressure reducing valves typically have an adjustable pressure setting function, allowing for flexible adjustments based on the actual hydrogen blending ratio and operating conditions.

[0081] Connecting the intake regulating chamber 7 to the high-pressure natural gas pipeline and the ejected fluid inlet 11 to the low-pressure hydrogen pipeline clearly defines and supplies the main gas flow and the ejected fluid. In particular, the sequential installation of check valves and pressure reducing valves along the gas flow direction on the low-pressure hydrogen pipeline effectively solves potential safety and stability issues during gas blending. The check valve reliably prevents high-pressure natural gas from flowing back into the low-pressure hydrogen pipeline, thus avoiding potential explosion risks and system contamination, greatly improving the operational safety of the device. At the same time, the pressure reducing valve precisely adjusts the hydrogen pressure to the stable low pressure required for ejection, ensuring a smooth ejection process and avoiding instability in the blending ratio caused by hydrogen pressure fluctuations. This allows the adjustable throat nozzle to more accurately control the blending ratio, thereby improving the overall efficiency and reliability of the hydrogen blending device. This configuration not only ensures operational safety but also provides a solid foundation for achieving high-precision and high-efficiency natural gas hydrogen blending.

[0082] In some embodiments described above in this application, a pipeline natural gas hydrogen blending device is proposed, which includes an adjustable throat nozzle, an inlet adjustment chamber 7, an intake chamber 8, a mixing chamber 9, and a diffusion chamber 10. The mixing chamber 9 is used to mix the gas entering from the ejector chamber with the gas drawn into the intake chamber 8, while the diffusion chamber 10 is located downstream of the mixing chamber 9 and is shaped like a frustum cone. However, during the gas mixing process, especially after initial mixing in the mixing chamber 9, the gas may not have reached a sufficiently uniform state, which may lead to local uneven concentration during downstream pipeline transportation or combustion, affecting the stability and safety of system operation.

[0083] To address this, this application further proposes a mixing plate 12 within the diffusion cavity 10 for thorough gas mixing. The mixing plate 12 is either a spiral blade or a porous plate disposed on the inner wall of the diffusion cavity 10. The mixing plate 12 is an internal component used to enhance fluid mixing efficiency. Its core function is to promote sufficient contact and diffusion between different component gas molecules by changing the fluid flow path, increasing the shear force between fluids, or generating local turbulence, ultimately achieving uniform mixing. When the mixing plate 12 is a spiral blade, it is typically designed to extend spirally along the inner wall of the diffusion cavity 10. This structure forces the fluid to flow along a spiral path, thereby extending the fluid's residence time within the diffusion cavity 10 and inducing rotational motion. This rotational motion generates centrifugal force, prompting the fluid to redistribute and mix in the radial direction. When the mixing plate 12 is a porous plate... In this configuration, the diffuser 10 typically consists of one or more plate-like structures with regular or irregular holes. When gas flows through the porous plate, it is divided into multiple fine streams. These streams re-merge after passing through the holes. This process of division and merging generates a large number of eddies and turbulence, greatly increasing the contact area and mixing opportunities between gas components. The shape of the holes can be circular, square, or other geometric shapes. Their diameter, spacing, and the number and arrangement of the porous plates can all be designed according to actual needs to balance mixing efficiency and pressure drop loss. By setting the mixing plate 12 in the diffuser 10, the problem of insufficient uniformity that may exist after the gas is initially mixed in the mixing chamber 9 can be effectively solved, avoiding safety hazards caused by local concentration unevenness during downstream pipeline transportation or combustion, and improving the operational stability and gas utilization efficiency of the hydrogen blending device.

[0084] In a pipeline natural gas hydrogen blending device, the blending ratio of hydrogen needs to be dynamically adjusted according to changes in downstream natural gas demand. The core component of the device is an adjustable throat nozzle, which is installed in the intake adjustment chamber 7. High-pressure natural gas enters the intake adjustment chamber 7 through the high-pressure natural gas pipeline as the ejector fluid. Low-pressure hydrogen enters the ejector fluid inlet 11 of the intake chamber 8 through the low-pressure hydrogen pipeline. The low-pressure hydrogen pipeline is equipped with a check valve and a pressure reducing valve in sequence to ensure a safe and stable supply of hydrogen.

[0085] The adjustable throat nozzle has a nozzle body 1 with multiple circumferentially arranged telescopic plates 2 inside. These telescopic plates 2 enclose a conical nozzle throat 3. Specifically, each telescopic plate 2 consists of an arc-shaped telescopic plate 1 201 and an arc-shaped telescopic plate 202 slidably fitted inside the arc-shaped telescopic plate 1 201. The two are the same in number and are arranged alternately in the circumferential direction. One end of each telescopic plate 2 is rotatably connected to the nozzle body 1, forming the lower bottom surface of the cone-shaped nozzle throat 3. Its area is relatively large, and the telescopic plates 2 are far from the nozzle body 1. One end of the rotatable connection forms the upper bottom surface of the cone-shaped body of the nozzle throat 3, i.e. the flow section 31. Its area is small and its diameter can be adjusted. Between each telescopic plate 2, especially on both sides along the length of the arc-shaped telescopic plate 201, a sliding seal 601 is provided. The sliding seal 601 has a sliding groove that is sealed and slidably engaged with the arc-shaped telescopic plate 202, ensuring the airtightness of the nozzle throat 3 during the adjustment process. A return spring 602 is also provided in the sliding groove, which abuts against the arc-shaped telescopic plate 202.

[0086] An annular fixed ring 4 is axially slidably fitted onto the outer side formed by the enclosing of each telescopic plate 2. The inner wall of the fixed ring 4 is provided with a conical guide surface, while the outer side of the arc-shaped telescopic plate 201 is provided with a driven inclined surface that cooperates with the conical guide surface. The drive assembly 5 includes a plurality of telescopic motors 501 and a plurality of telescopic rods 502 controlled by the movement of the telescopic motors 501, and is pivotally connected to the fixed ring 4. The number of telescopic motors 501, telescopic rods 502 and arc-shaped telescopic plates 201 are all equal, ensuring synchronous drive.

[0087] When it is necessary to reduce the flow section 31 of the nozzle throat 3 to increase the ejector velocity and hydrogen doping ratio, the telescopic motor 501 of the drive assembly 5 is activated, driving the telescopic rod 502 to move the fixed ring 4 along the axial direction of the nozzle throat 3 away from the flow section 31. At this time, the conical guide surface of the fixed ring 4 cooperates with the driven inclined surface of the arc-shaped telescopic plate 201, converting the axial movement of the fixed ring 4 into a radial thrust on the arc-shaped telescopic plate 201, driving the arc-shaped telescopic plate 201 to retract towards the central axis of the nozzle throat 3. As the sliding seal 601 drives the flow section 31 of the arc-shaped telescopic plate 202 to move synchronously toward the central axis of the nozzle throat 3, the arc-shaped telescopic plate 201 and the arc-shaped telescopic plate 202 are positioned close to each other at one end of the flow section 31, jointly driving the flow section 31 of the nozzle throat 3 to become smaller. During this process, the return spring 602 is compressed. Compared with the traditional fixed throat structure, this solution realizes dynamic and continuous adjustment of the throat size, which can adapt to different hydrogen doping ratio requirements.

[0088] When it is necessary to increase the flow cross-section of the nozzle throat 3 to reduce the ejector velocity and hydrogen doping ratio, the telescopic motor 501 of the drive assembly 5 moves in the opposite direction, driving the telescopic rod 502 to move the fixed ring 4 along the axial direction of the nozzle throat 3 toward one end of the flow cross-section. At this time, the radial constraint of the fixed ring 4 on the arc-shaped telescopic plate 201 is reduced, and the compressed return spring 602, through elastic deformation, drives the arc-shaped telescopic plate 201 and the arc-shaped telescopic plate 202 to be positioned away from each other at one end of the flow cross-section, thereby driving each telescopic plate 2 to move away from the central axis of the nozzle throat 3, making the flow cross-section of the nozzle throat 3 larger. This self-resetting mechanism based on the elastic seal 6 and the return spring 602 simplifies the adjustment mechanism, avoids the complexity of traditional multi-stage valve control systems or external adjustment mechanisms, and improves the response speed.

[0089] Throughout the adjustment process, the axial movement distance of the fixed ring 4 is proportional to the change in the equivalent diameter of the flow section of the nozzle throat 3. Through the precise cooperation between the tapered guide surface and the driven inclined surface, the conversion between the axial movement of the fixed ring 4 and the synchronous radial extension and retraction of each telescopic plate 2 is realized, ensuring the accuracy of the adjustment. Compared with the traditional design that lacks a precise linear relationship between the adjustment mechanism and the throat size, this solution provides precise proportional control capability. At the same time, the setting of the sliding seal 601 and the return spring 602 ensures the tight fit and reliable sealing between the telescopic plates 2, effectively avoiding the leakage risk that may occur in high-pressure flammable and explosive environments, and improving the inherent safety of the device.

[0090] Natural gas and hydrogen are ejected and mixed at the flow section of the adjustable throat nozzle before entering the mixing chamber 9. The inlet of the mixing chamber 9 is connected to the intake chamber 8. The mixed gas then enters the diffusion chamber 10 located downstream of the mixing chamber 9. The diffusion chamber 10 is truncated cone-shaped and has a mixing plate 12 inside for fully mixing the gas. The mixing plate 12 is in the form of a spiral blade or a porous plate set on the inner wall of the diffusion chamber 10, which further ensures the uniform mixing of natural gas and hydrogen. Through the precise adjustment of the adjustable throat nozzle, the pipeline natural gas hydrogen blending device can maintain a stable blending ratio under fluctuating flow conditions, meeting the flexible requirements for the hydrogen blending ratio in different application scenarios.

Claims

1. An adjustable throat nozzle for gas ejection and mixing, characterized in that, include: The nozzle body is equipped with at least two circumferentially arranged telescopic plates that surround and form a nozzle throat. The nozzle throat formed by the telescopic plates is conical. One end of each telescopic plate is rotatably connected to the nozzle body. The end of each telescopic plate away from the rotatable connection has a movable and variable diameter flow section. An elastic seal is provided between each telescopic plate. A fixed ring is axially slidably fitted onto the outer side formed by the enclosing of each telescopic plate; A drive assembly, connected to the fixed ring, is used to drive the fixed ring to move axially along the nozzle throat; When the drive assembly drives the fixed ring to move away from the flow section, the fixed ring drives each telescopic plate to contract in the direction of the central axis of the nozzle throat, thereby reducing the flow section of the nozzle throat; when the drive assembly drives the fixed ring to move in the direction of the flow section, the elastic seal drives each telescopic plate to move away from the central axis of the nozzle throat through elastic deformation, thereby increasing the flow section of the nozzle throat. The telescopic plate includes an arc-shaped telescopic plate one and an arc-shaped telescopic plate two slidably sleeved within the arc-shaped telescopic plate one. Both the arc-shaped telescopic plate one and the arc-shaped telescopic plate two are provided with a plurality of equal numbers of arc-shaped telescopic plates arranged in a staggered manner along the circumference to form a nozzle throat. The fixed ring is annular and its inner wall is provided with a conical guide surface. The outer side of the arc-shaped telescopic plate one is provided with a driven inclined surface that cooperates with the conical guide surface. When the fixed ring is axially moved by the controlled drive assembly, the radial telescopic movement of each telescopic plate is converted into synchronous telescopic movement through the cooperation of the conical guide surface and the driven inclined surface. The elastic seal includes a sliding seal and a return spring connected to both sides along the length of the first arc-shaped telescopic plate. When one end of the flow section of the first arc-shaped telescopic plate is controlled by the fixed ring to contract toward the central axis of the nozzle throat, the sliding seal drives one end of the flow section of the second arc-shaped telescopic plate to move synchronously toward the central axis of the nozzle throat, causing the flow section of the nozzle throat to become smaller. The first arc-shaped telescopic plate and the second arc-shaped telescopic plate are positioned close to each other at one end of the flow section, causing the return spring to be in a compressed state. When the fixed ring moves toward one end of the flow section, the reset spring drives the arc-shaped telescopic plate one and the arc-shaped telescopic plate two to be positioned far apart from each other at one end of the flow section through elastic deformation, thereby increasing the flow section of the nozzle throat.

2. An adjustable throat nozzle for gas ejection and mixing according to claim 1, characterized in that, The axial movement distance of the fixed ring is proportional to the change in the equivalent diameter of the flow section of the nozzle throat.

3. An adjustable throat nozzle for gas ejection and mixing according to claim 1, characterized in that, The sliding seal has a sliding groove that cooperates with the second arc-shaped telescopic plate in a sliding manner, and the return spring is disposed in the sliding groove and abuts against the second arc-shaped telescopic plate.

4. An adjustable throat nozzle for gas ejection and mixing according to claim 1, characterized in that, The nozzle throat formed by the arc-shaped telescopic plate one and the arc-shaped telescopic plate two is in the shape of a frustum. One end of each telescopic plate is rotatably connected to the nozzle body and is the lower bottom surface of the frustum of the nozzle throat. The flow section is the upper bottom surface of the frustum of the nozzle throat, and the area of ​​the lower bottom surface is larger than the area of ​​the upper bottom surface.

5. An adjustable throat nozzle for gas ejection and mixing according to claim 1, characterized in that, The drive assembly includes several telescopic motors and several telescopic rods controlled by the movement of the telescopic motors. The telescopic rods are pivotally connected to the fixed ring. The number of telescopic motors, the number of telescopic rods, and the number of arc-shaped telescopic plates are all equal.

6. A pipeline natural gas hydrogen blending device, characterized in that, include: Adjustable throat nozzle as described in any one of claims 1 to 5; An intake adjustment chamber, wherein the adjustable throat nozzle is installed inside the intake adjustment chamber; The air intake chamber is arranged opposite to the flow section of the adjustable throat nozzle, and the side wall of the air intake chamber is provided with an inlet for the ejected fluid. The mixing chamber, whose inlet is connected to the suction chamber, is used to mix the gas entering from the ejector chamber with the gas being drawn into the suction chamber. The diffusion chamber is located downstream of the mixing chamber and is shaped like a frustum of a cone.

7. A pipeline natural gas hydrogen blending device according to claim 6, characterized in that, The intake adjustment chamber is connected to a high-pressure natural gas pipeline, and the ejected fluid inlet is connected to a low-pressure hydrogen pipeline. A check valve and a pressure reducing valve are sequentially installed on the low-pressure hydrogen pipeline along the airflow direction.

8. A pipeline natural gas hydrogen blending device according to claim 6, characterized in that, The diffusion cavity is provided with a mixing plate for fully mixing the gas. The mixing plate is in the shape of a spiral blade or a porous plate disposed on the inner wall of the diffusion cavity.

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