Built-in groove type supersonic rotational flow device and separation method thereof

Abstract

The invention relates to the technical field of supersonic flowing and low-temperature separation, and particularly discloses a built-in groove type supersonic rotational flow device and a separation method thereof.The built-in groove type supersonic rotational flow device comprises a steady flow section, a Laval spray pipe and a separation section which are sequentially connected in the airflow direction, and a hydrocyclone is arranged in the steady flow section; the Laval spray pipe comprises a contraction section, a throat part and an expansion section which are sequentially connected in the airflow direction, the inner wall of the contraction section is coated with a low-wettability coating, the inner wall of the expansion section is coated with a high-wettability coating, and a spiral groove is formed in the wall face. Through the synergistic effect of the swirler and the spiral groove, the swirling strength of a flow field is enhanced, and the wall-leaning migration efficiency of condensed liquid drops is improved; through the collaborative design of the spiral groove and the wettability coating, efficient gathering of liquid drops is achieved, the risk that the liquid drops are secondarily entrained by high-speed airflow is greatly reduced, and therefore the flow resistance and energy loss in the supersonic rotational flow separation process are reduced while the separation efficiency is guaranteed.

Description

Technical Field

[0001] This application relates to the technical field of supersonic flow and cryogenic separation, and in particular to a built-in grooved supersonic vortex device and its separation method. Background Technology

[0002] Natural gas, as the cleanest fossil fuel, plays a crucial "bridging" role in the transition from fossil fuels to green and clean energy, significantly reducing carbon dioxide emissions compared to more polluting fossil fuels. However, during pipeline transportation and pressure regulation, water vapor components combine with acidic components, causing pipeline corrosion. Under certain pressure and temperature, this can form hydrates that clog the pipeline, greatly reducing its transport capacity. Therefore, the condensation of water vapor components in natural gas is essential for pipeline transportation.

[0003] Water vapor condensation generally employs adsorption, absorption, and membrane separation technologies. However, these conventional methods often suffer from problems such as high operational and maintenance difficulty, high investment costs, high energy consumption, and easy pollution. In contrast, ultrasonic cyclone separation, as an emerging technology in the field of natural gas dehydration, highly couples ultrasonic flow, condensation phase change, and gas-liquid separation processes, and has advantages such as simple and compact structure, leak-proof sealing, and green environmental protection.

[0004] The supersonic cyclone separator mainly consists of key components such as a flow stabilization section, a cyclone separator, a Laval nozzle, a separation structure, and a diffuser section. Among these, the Laval nozzle, as the core component, utilizes its unique structure to enable the fluid medium to transition from subsonic to supersonic speeds. Within the diffuser section, the rapid expansion of the gas flow creates a low-temperature, low-pressure environment, providing conditions for the condensation phase change of condensable components. Droplets migrate towards the pipe wall under the influence of the high-speed cyclone and are discharged through the drainage structure. The high-speed gas flow recovers kinetic energy within the diffuser section, reducing energy loss. This achieves a rapid and efficient separation process, enabling the dehydration of natural gas.

[0005] While existing publicly available devices have improved gas-liquid separation efficiency in supersonic flow fields to some extent, they all suffer from significant pressure loss and energy consumption. Furthermore, existing technologies have not yet conducted systematic research and optimization design on processes such as wall migration of condensed droplets, swirling enhancement, and efficient droplet aggregation. Summary of the Invention

[0006] To address the problems of high pressure loss and high energy consumption in gas-liquid separation in existing supersonic cyclone devices, as well as insufficient research and optimization of physical processes such as droplet migration near the wall, cyclone enhancement, and efficient droplet aggregation, this application provides a supersonic cyclone device with built-in grooves and its separation method.

[0007] On the one hand, the supersonic vortex device with built-in groove provided in this application adopts the following technical solution: A built-in grooved supersonic vortex device includes: The flow stabilization section, the Laval nozzle, and the separation section are connected sequentially along the airflow direction. A cyclone separator is installed in the flow stabilization section. The Laval nozzle includes a converging section, a throat, and a dilating section connected sequentially along the airflow direction. The converging section is connected to the stabilizing section, and the dilating section is connected to the separating section. The diameter of the dilating section gradually expands along the airflow direction, and a groove is formed inside the throat. The groove is spiral in shape. The separation section is equipped with a diffuser section and a liquid phase outlet. The diffuser section and the separation section are coaxially arranged. The diffuser section is equipped with a dry gas channel. A liquid discharge gap is provided between the diffuser section and the separation section. The liquid discharge gap is connected to an annular liquid collection channel. An annular liquid collection channel is provided in the separation section. The liquid phase outlet is connected to the annular liquid collection channel.

[0008] By adopting the above technical solutions, the contraction section of the Laval nozzle adopts the Vitosinski curve shape to ensure uniform flow field distribution and reduce local eddies and pressure loss. The expansion section is equipped with spiral grooves, which work in conjunction with the cyclone separator to enhance the swirling intensity and avoid excessive energy consumption. The diffuser section is designed with a cone angle of 3°~6° to smoothly decelerate the supersonic airflow and gradually restore the pressure, thereby realizing kinetic energy recovery.

[0009] In some embodiments, the hydrocyclone includes a central body and guide vanes, the guide vanes being arranged at circumferential intervals along the central body; The central body has an axial section, which is elliptical in shape, and the ratio of the minor axis to the major axis of the axial section is 1:2 to 1:4. The angle of the guide vanes is 20°~40°, and the number of guide vanes is 8~12.

[0010] In some embodiments, the groove angle is consistent with the angle of the guide vanes of the hydrocyclone, the groove shape is arc-shaped, the groove angle is 20°~40°, the groove depth is 0.5~1.0 mm, and the groove width is 0.5~1.0 mm.

[0011] In some embodiments, the inner wall of the converging section of the Laval nozzle is coated with a low-wetting coating, the droplet static contact angle of which is greater than 150°.

[0012] In some embodiments, the expansion section is a tapered tube, and the inner wall of the expansion section of the Laval nozzle is coated with a highly wettable coating with a static contact angle of less than 90° for the droplets.

[0013] In some implementations, the size of the drainage gap is 0.5 mm to 3 mm.

[0014] In some implementations, the cone angle of the diffuser section is 3° to 6°.

[0015] In some implementations, the flow stabilization section is detachably connected to the Laval nozzle, and the Laval nozzle is detachably connected to the separation section.

[0016] In some implementations, the diameter of the flow stabilization section is the same as the inlet diameter of the converging section of the Laval nozzle, and the length of the flow stabilization section is 10 to 15 times the diameter of the throat.

[0017] On the other hand, this application provides a separation method using a built-in grooved supersonic vortex device, employing any of the above-mentioned built-in grooved supersonic vortex devices, comprising the following steps: S1: The mixed gas containing condensable components enters the supersonic cyclone separator and passes through the flow stabilization section to make the flow field uniform and stable. S2: The mixed gas enters the Laval nozzle in a swirling manner. Under the synergistic effect of the swirler and the spiral groove, the swirling intensity is enhanced, and the efficiency of droplet migration to the wall is improved. At the same time, the droplets gather to form a liquid film under the action of the highly wettable coating on the inner wall of the expansion section of the Laval nozzle. S3: The liquid film that accumulates on the wall of the expansion section of the Laval nozzle is discharged after flowing along the wall through the liquid discharge gap into the annular liquid collection channel under the action of high-speed swirling flow. The high-speed airflow enters the diffuser section along the dry gas channel. Gas-liquid separation under supersonic conditions is achieved through the coupling of the spiral groove and the highly wettable coating. S4: In the diffuser section, the velocity of the high-speed mainstream gradually decreases and the pressure increases, achieving kinetic energy recovery and reducing energy loss.

[0018] Compared with the prior art, this application includes at least one of the following beneficial technical effects: 1. The contraction section of the Laval nozzle adopts the Vitosinski curve shape to ensure uniform flow field distribution and reduce local eddies and pressure loss. The expansion section is equipped with spiral grooves, which work in conjunction with the cyclone separator to enhance the swirling intensity and avoid excessive energy consumption. The diffuser section is designed with a cone angle of 3°~6° to smoothly decelerate the supersonic airflow and gradually restore pressure, thereby achieving kinetic energy recovery, reducing shock wave generation, lowering overall flow resistance, and reducing energy loss. Compared with traditional supersonic separation devices, this device improves pressure recovery efficiency while ensuring separation efficiency. 2. The spiral grooves are aligned with the guide vanes of the hydrocyclone to ensure a matching swirling field and improve the wall migration efficiency of condensate droplets. At the same time, the spiral groove structure improves flow stability, reduces shock wave formation, and prevents condensate droplet re-evaporation. 3. The low wettability coating reduces the adhesion and retention of entrained droplets on the contraction section wall, avoids throat blockage, and ensures smooth airflow acceleration; the high wettability coating enables efficient droplet aggregation and reduces the risk of droplets being entrained again by high-speed airflow. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application; Figure 2 This is an internal sectional view of an embodiment of this application; Figure 3 This is a schematic diagram of the structure of the cyclone separator in the embodiments of this application; Figure 4 This is a cross-sectional view of the Laval nozzle in an embodiment of this application; Figure 5 This is a cross-sectional view of the separated section in an embodiment of this application.

[0020] In the picture: 1. Stabilizing section; 11. Cyclone separator; 12. Central body; 13. Guide vane; 2. Laval nozzle; 21. Contraction section; 22. Throat; 23. Diffusion section; 25. Groove; 3. Separation section; 31. Annular liquid collection channel; 4. Diffusion section; 41. Dry gas channel; 42. Liquid discharge gap; 5. Mixed gas inlet; 6. Liquid phase outlet; 7. Dry gas outlet. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0022] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the term "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Furthermore, the character " / " in this document, unless otherwise specified, generally indicates that the preceding and following related objects have an "or" relationship.

[0023] Reference Figures 1 to 4This application provides a built-in grooved supersonic vortex device, comprising a stabilizing section 1, a Laval nozzle 2, and a separating section 3 connected sequentially along the airflow direction X. A vortex generator 11 is fixedly installed within the stabilizing section 1. A mixed gas inlet 5 is provided on the side of the stabilizing section 1 away from the Laval nozzle 2. The mixed gas enters the stabilizing section 1 from the mixed gas inlet 5 and passes sequentially through the Laval nozzle 2 and the separating section 3. The Laval nozzle 2 includes a contraction section 21, a throat 22, and an expansion section 23 connected sequentially along the airflow direction X. The contraction section 21 is connected to the stabilizing section 1, and the expansion section 23 is connected to the separating section 3. The contraction section 21 adopts a Vitósinski curve, and the expansion section 23 is a tapered tube with its diameter gradually expanding along the airflow direction X. A groove 25 is provided within the expansion section 23, and the groove 25 is spiral in shape. A diffuser section 4 is fixed within the separation section 3. A liquid phase outlet 6 is provided on the separation section 3, with the axis of the liquid phase outlet 6 perpendicular to the axis of the diffuser section 4. The diffuser section 4 and the separation section 3 are coaxially arranged. A dry gas channel 41 is provided within the diffuser section 4, and a dry gas outlet 7 is provided at the end of the diffuser section 4 away from the Laval nozzle 2. A liquid discharge gap 42 is provided between the diffuser section 4 and the separation section 3. An annular liquid collection channel 31 is provided within the separation section 3, and the liquid discharge gap 42 is connected to the annular liquid collection channel 31. The liquid phase outlet 6 is connected to the annular liquid collection channel 31.

[0024] The flow field is kept uniform and stable by setting up a steady flow section 1, providing a foundation for subsequent separation. The contraction section 21 of the Laval nozzle 2 uses the Vitosinski curve (a classic engineering model in hypersonic aerodynamics, which will not be elaborated here), ensuring uniform flow field distribution and reducing pressure loss. The expansion section 23 uses a tapered tube, which is easy to manufacture. The spiral grooves 25 in the expansion section 23 work in conjunction with the hydrocyclone 11 to enhance the swirling intensity and improve the efficiency of droplet migration to the wall. The drain gap 42 and annular collection channel 31 in the separation section 3 allow for efficient discharge of the liquid film, while the dry gas channel 41 and diffuser section 4 achieve kinetic energy recovery and reduce energy loss. The overall device has a compact structure, reduces flow resistance, and improves separation efficiency.

[0025] Furthermore, in this embodiment, the flow stabilizing section 1 and the Laval nozzle 2 are detachably connected, and the Laval nozzle 2 and the separation section 3 are also detachably connected. Specifically, the flow stabilizing section 1 and the Laval nozzle 2 can be connected by a flange or a clamp, which is not limited here. By providing detachable connections, the supersonic vortex device can be quickly cleaned, and the coating or groove 25 components can be replaced, which helps to extend the device's lifespan.

[0026] In this embodiment, the cyclone separator 11 includes a central body 12 and guide vanes 13, which are arranged at intervals along the circumference of the central body 12. The central body 12 has an axial cross-section that is elliptical, with the ratio of its minor axis to its major axis being 1:2 to 1:4. The angle of the guide vanes 13 is 20° to 40°, and the number of guide vanes 13 is 8 to 12. The elliptical structure of the central body 12 optimizes the streamline shape, reduces flow resistance and eddy generation, and avoids disruption of the main flow field. The guide vanes 13 provide a moderate tangential velocity, balancing the swirling intensity and pressure loss. In this embodiment, the number of guide vanes 13 is preferably 10, which helps to ensure a uniform and stable swirling field and avoid local flow separation.

[0027] Furthermore, in this embodiment, the angle of the groove 25 is consistent with the angle of the guide vanes 13 of the hydrocyclone 11, which ensures that the swirling field matches the flow direction of the groove 25, avoids flow field disturbance, and enhances the swirling intensity. The groove 25 is arc-shaped, which helps to reduce flow resistance, promotes the directional movement of the liquid film along the groove 25, and prevents droplet retention. The depth of the groove 25 is 0.5~1.0 mm, and the width of the groove 25 is 0.5~1.0 mm. The depth and width of the groove 25 are within the range of 0.5~1.0 mm, which can effectively guide the liquid film without excessively affecting the airflow velocity, thereby improving the efficiency of droplet aggregation and discharge.

[0028] In some embodiments, the inner wall of the converging section 21 of the Laval nozzle 2 is coated with a low-wetting coating. The static contact angle of the droplets in the low-wetting coating is greater than 150°. The low-wetting coating is made of a low-surface-energy fluoride material or an inorganic nanoparticle composite material, such as a polytetrafluoroethylene coating or a polypropylene coating. The high contact angle makes it difficult for droplets to adhere to the wall of the converging section 21, preventing droplet accumulation from affecting the flow of the throat 22, avoiding droplet retention that could lead to local flow blockage, and maintaining a smooth and accelerated airflow. Fluorides or nanomaterials have low surface energy, good durability, and are suitable for high-pressure, high-speed environments.

[0029] In some embodiments, the inner wall of the expansion section 23 of the Laval nozzle 2 is coated with a highly wettable coating. The static contact angle of the droplets in the highly wettable coating is less than 90°. The highly wettable coating is made of metal oxide materials or polymer materials, such as titanium dioxide coatings or polyvinylidene fluoride coatings. The low contact angle allows the droplets to spread rapidly into a liquid film, improving droplet aggregation efficiency. The liquid film is more stable under high-speed airflow, reducing the risk of droplets being re-entrained into the airflow. Metal oxides (such as titanium dioxide) or polymer materials (such as polyvinylidene fluoride) have good wear resistance and chemical stability.

[0030] In this embodiment, the diameter of the stabilizing section 1 is the same as the inlet diameter of the contraction section 21 of the Laval nozzle 2, and the length of the stabilizing section 1 is 10 to 15 times the diameter of the throat 22. The size of the discharge gap 42 is 0.5 mm to 3 mm, and the cone angle of the diffuser section 4 is 3° to 6°. The size range of 0.5 mm to 3 mm ensures smooth discharge of the liquid film, prevents dry gas leakage into the collection channel, and avoids airflow crosstalk due to excessive gap or liquid film blockage due to insufficient gap, thus maintaining a stable dry airflow field. The optimized cone angle design allows the supersonic airflow to gradually decelerate, the pressure to return to a stable state, and avoids shock wave generation.

[0031] This application also provides a separation method using a built-in grooved supersonic vortex device, which includes the following steps: S1: A mixed gas containing condensable components enters the supersonic cyclone separator under certain operating conditions. After passing through the flow stabilization section 1, the flow field becomes uniform and stable. Subsequently, the mixed gas obtains an initial tangential velocity under the action of the hydrocyclone 11, providing rotational momentum for subsequent cyclone separation. S2: The mixed gas enters the Laval nozzle 2 in a swirling manner, with the flow velocity gradually accelerating from subsonic to supersonic. As the pressure and temperature inside the nozzle continuously decrease, a low-temperature, low-pressure environment is created. During this process, the condensable components in the mixed gas spontaneously condense, undergoing a phase change to produce droplets. The synergistic effect of the swirler 11 and the spiral groove 25 further enhances the swirling intensity, improving the efficiency of droplet migration to the wall of the Laval nozzle 2. Simultaneously, the highly wettable coating on the inner wall of the expansion section 23 of the Laval nozzle 2 helps droplets rapidly accumulate on the wall to form a liquid film.

[0032] S3: The liquid film that accumulates on the wall of the expansion section 23 of the Laval nozzle 2 is discharged after flowing along the wall through the discharge gap 42 into the annular liquid collection channel 31 under the action of high-speed swirling flow. The high-speed airflow enters the diffuser section 4 along the dry gas channel 41. Gas-liquid separation under supersonic conditions is achieved through the coupling of the spiral groove 25 and the highly wettable coating.

[0033] S4: In diffuser section 4, the velocity of the high-speed mainstream gradually decreases and the pressure increases, achieving kinetic energy recovery and reducing energy loss.

[0034] The working principle of the built-in grooved supersonic cyclone device in this embodiment is as follows: A mixed gas containing condensable components (such as natural gas) enters the supersonic cyclone separator under certain operating conditions. After passing through the stabilization section 1, the flow field becomes uniform and stable. Subsequently, the natural gas gains an initial tangential velocity under the action of the cyclone separator 11, providing rotational momentum for subsequent cyclone separation. Then, the natural gas enters the Laval nozzle 2 in a cyclone manner, with the flow velocity gradually accelerating from subsonic to supersonic. As the pressure and temperature inside the nozzle continuously decrease, a low-temperature, low-pressure environment is formed. During this process, the carbon dioxide component in the natural gas spontaneously condenses, and a phase change produces carbon dioxide droplets. Under the synergistic effect of the cyclone separator 11 and the spiral groove 25, the cyclone intensity is further enhanced, improving the efficiency of carbon dioxide droplet migration to the wall of the Laval nozzle 2. Simultaneously, water droplets in the natural gas accumulate on the inner wall of the expansion section 23 of the Laval nozzle 2 to form a liquid film, greatly reducing the risk of carbon dioxide droplets being secondary entrained by the high-speed airflow. Under the action of high-speed swirling flow, the liquid film flows along the wall surface through the drain gap 42 and into the annular liquid collection channel 31 before being discharged. The high-speed gas flow enters the diffuser section 4 along the dry gas channel 41, and through the coupling of the spiral groove 25 with the inner wall coating of the expansion section 23, gas-liquid separation is achieved under supersonic conditions. In the diffuser section 4, the flow velocity of the dry gas component in the natural gas gradually decreases while the pressure increases, achieving kinetic energy recovery and reducing energy loss. Thus, while ensuring separation efficiency, it ensures that the separated dry gas meets the requirements of subsequent processes.

[0035] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An internally grooved supersonic swirl device, characterized by, The utility model relates to a kind of Laval nozzle, including: Steady flow section (1), Laval nozzle (2) and separation section (3) are sequentially connected in airflow direction, and the steady flow section (1) is fixedly provided with cyclone (11) in it; The Laval nozzle (2) includes sequentially connected contraction section (21), throat (22) and expansion section (23) in airflow direction, the contraction section (21) is connected with the steady flow section (1), the expansion section (23) is connected with the separation section (3), the pipe diameter of the expansion section (23) gradually expands along airflow direction, the expansion section (23) is provided with groove (25), and the groove (25) is spiral type; The separation section (3) is provided with diffuser section (4), the separation section (3) is provided with liquid phase outlet (6), the diffuser section (4) is coaxially arranged with the separation section (3), the diffuser section (4) is provided with dry gas passage (41), the diffuser section (4) and the separation section (3) are provided with liquid discharge gap (42), the separation section (3) is provided with annular liquid collection passage (31), the liquid discharge gap (42) is communicated with the annular liquid collection passage (31), and the liquid phase outlet (6) is communicated with the annular liquid collection passage (31).

2. The built-in grooved supersonic cyclone device according to claim 1, characterized in that: The cyclone (11) includes center body (12) and guide vane (13), and the guide vane (13) is arranged along the circumference of the center body (12); The center body (12) has an axial section, and the axial section is elliptical, and the ratio of the short axis to the long axis of the axial section is 1:2~1:4; The guide vane (13) is a twisted blade, the twist angle of the guide vane (13) is 20°~40°, and the number of the guide vane (13) is 8~12.

3. The built-in grooved supersonic cyclone device according to claim 2, characterized in that: The angle of the groove (25) is consistent with the angle of the guide vane (13) of the cyclone (11), the groove (25) is semicircular, the depth of the groove (25) is 0.5~1.0 mm, and the width of the groove (25) is 0.5~1.0 mm.

4. The built-in grooved supersonic cyclone device according to claim 1, wherein: The line type of the contraction section (21) is selected from Vitoshinsky curve, the inner wall of the contraction section (21) of the Laval nozzle (2) is coated with a low-wetting coating, and the static contact angle of the low-wetting coating droplet is greater than 150°.

5. The built-in grooved supersonic cyclone device according to claim 1, wherein: The expansion section (23) adopts a conical tube, and the inner wall of the expansion section (23) of the Laval nozzle (2) is coated with a high-wetting coating, and the static contact angle of the high-wetting coating droplet is less than 90°.

6. The built-in grooved supersonic cyclone device according to claim 1, wherein: The size of the liquid discharge gap (42) is 0.5mm~3mm.

7. The built-in grooved supersonic cyclone device according to claim 1, wherein: The taper angle of the diffuser section (4) is 3°~6°.

8. The built-in grooved supersonic cyclone device according to claim 1, wherein: The steady flow section (1) and the Laval nozzle (2) are detachably connected, and the Laval nozzle (2) and the separation section (3) are detachably connected.

9. The built-in grooved supersonic cyclone device according to claim 1, wherein: The pipe diameter of the steady flow section (1) is the same as the inlet diameter of the contraction section (21) of the Laval nozzle (2), and the length of the steady flow section (1) is 10~15 times the diameter of the throat (22).

10. A separation method of an in-line grooved supersonic cyclone device, characterized by, The built-in groove supersonic cyclone device as claimed in any one of claims 1-9 comprises the following steps: S1: the mixed gas containing condensable components enters the supersonic cyclone separation device, and the flow field is uniformly and stably through the steady flow section (1); S2: the mixed gas enters the Laval nozzle (2) in a cyclone manner, the cyclone intensity is enhanced under the synergistic action of the cyclone (11) and the spiral groove (25), the liquid droplet migration efficiency to the wall surface is improved, and the liquid droplets are gathered to form a liquid film under the action of the high-wetting coating on the inner wall of the expansion section (23) of the Laval nozzle (2); S3: the liquid film gathered on the wall surface of the expansion section (23) of the Laval nozzle (2) is discharged along the wall surface under the action of high-speed cyclone and then enters the annular liquid collection channel (31) through the liquid discharge gap (42), and the high-speed gas flow enters the diffuser section (4) along the dry gas channel (41); through the coupling of the spiral groove (25) and the high-wetting coating, the gas-liquid separation under the supersonic state is realized; S4: in the diffuser section (4), the flow rate of the high-speed main flow is gradually reduced, the pressure is increased, the kinetic energy is recovered, and the energy loss is reduced.

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