Disc type channel suitable for limited space

Abstract

The invention provides a disc-type channel suitable for a limited space, which belongs to the technical field of high-temperature gas magnetohydrodynamic power generation and comprises a gas inlet section, an effective section and a turning section. And airflow flows out of the exhaust port after passing through the air inlet section, the effective section and the turning section from the air inlet. The turning section is composed of step flow deflectors and at least three stages of small-angle turning structures, elastic coatings are laid on the inner walls of the at least three stages of small-angle turning structures, air suction holes are formed in the first-stage small-angle turning structure and the second-stage small-angle turning structure, and sucked air is conveyed to an exhaust port through an air suction flow guide pipe to be converged and flow out. The device is suitable for being used in a limited space environment, boundary layer flow separation can be restrained, the shock wave intensity in the channel is weakened, power generation working medium ionization is enhanced, and finally the disc type channel power generation performance is improved.

Description

Technical Field

[0001] This invention belongs to the field of high-temperature gas magnetohydrodynamic power generation technology, specifically relating to a disc-type channel suitable for confined spaces. Background Technology

[0002] Magnetohydrodynamic (MHD) power generation is a novel method of directly converting thermal energy into electrical energy. Unlike traditional power generation, it uses conductive fluids, such as plasma, liquid metal, or seawater, instead of conductive solids. Plasma MHD generators are generally classified into Faraday-type and disk-type MHD generators. In the former, the electrodes are typically located on both sides of the channel, and the power generation area is a rectangular or expanded channel. In the latter, the typical power generation channel is a disk structure, with electrodes distributed at the inlet and outlet of the effective section, usually a closed-loop MHD power generation method. In a disk-type MHD generator, the conductive working fluid flows radially, and the magnetic field is along the axial direction. The conductive gas cuts the magnetic field, generating Faraday current and radial current (Hall current). Electrodes arranged in the direction of airflow draw out the radial current, while the tangential current component (Faraday current) is completely short-circuited and perpendicular to the airflow and magnetic field directions. The power generation of a disk-type MHD generator relies entirely on the Hall effect.

[0003] like Figure 1 As shown, disc channels are often used in conjunction with solenoid superconducting magnets to leverage their small size and reduce the difficulty of magnet manufacturing. The temperature orifice of the solenoid superconducting magnet is shaped like a hollow circular tube, serving as the room temperature space for magnetic field generation. Gas flows into the inlet section of the disc channel through the inlet, passes through the effective section and the turning section, and finally flows out of the disc channel through the exhaust port. The use of a solenoid superconducting magnet indirectly increases the requirements for the disc channel; that is, the flow path of the disc channel in the solenoid superconducting magnet must change from axial to radial and then back to axial. In other words, within the confined space of the solenoid superconducting magnet, the flow path of the disc channel undergoes two 90-degree transitions. After the first 90-degree turn, the working fluid enters the effective section of the power generation channel. To obtain higher power, the working fluid flows at supersonic or high speed. Continuing through the second 90-degree turn, the velocity changes drastically, generating a high-intensity shock wave, which then reduces the velocity and increases the pressure at the wall, creating a reverse pressure gradient and causing significant flow losses, thus significantly reducing the performance of the disc channel.

[0004] Figure 2 The diagram shows the RZ plane velocity streamline distribution in a disc-type channel in the prior art. The channel transitions from radial to axial direction using a single-stage arc shape. It can be seen that there is obvious boundary layer flow separation in the upper part of the region from the effective section to the turning section. Figure 2Flow separation point 1 divides the channel into two parts. Upstream of the flow separation point, the fluid flows towards the exhaust port. Downstream of the flow separation point, due to fluid viscosity and pressure increase caused by the bend, the fluid flows towards the intake port, resulting in zero fluid velocity at flow separation point 1. The airflow is compressed towards the middle of the channel, further forming a significant boundary layer flow separation region in the upper part. Similarly, boundary layer flow separation also exists in the lower part of the effective section and the bend section of the channel, forming flow separation point 2. Figure 3 The paper presents the RZ plane Mach number distribution diagram in a disc-type channel in the prior art. Before point A, the Mach number in the channel gradually increases, with all Mach numbers greater than 1, indicating a supersonic state. After point A, due to fluid viscosity and pressure increases caused by bends, the fluid Mach number rapidly decreases to below 1, and the flow becomes subsonic, generating shock waves. Similarly, shock waves are generated at point B. Boundary layer flow separation increases flow resistance losses, and the generation of shock waves causes some kinetic energy to be converted into heat energy, leading to a decrease in airflow velocity and energy loss. Simultaneously, it exacerbates boundary layer flow separation, ultimately reducing the performance of the disc generator. Therefore, achieving an efficient disc-type power generation channel in a confined space is a key issue. Currently, there are no literature reports on controlling boundary layer flow separation and weakening shock waves in similar confined spaces. Summary of the Invention

[0005] To address the technical challenges of controlling 90-degree supersonic / high-speed airflow turns within confined spaces, suppressing boundary layer flow separation, and weakening or eliminating single-stage shock wave intensity, this invention provides a disc-shaped channel suitable for confined spaces, comprising an inlet section, an effective section, and a turning section. Airflow enters through the inlet, passes through the inlet section, the effective section, and the turning section, and exits through the exhaust port. The turning section consists of stepped guide vanes and at least three small-angle turning structures. The inner walls of the at least three small-angle turning structures are coated with an elastic coating. Extraction holes are located on the first and second small-angle turning structures, and the extracted gas is delivered to the exhaust port via an extraction guide pipe to converge and exit. This invention is applicable to confined space environments, effectively suppressing boundary layer flow separation, weakening shock wave intensity within the channel, reducing energy loss, and improving generator performance.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A disc-shaped channel suitable for confined spaces includes an intake section, an effective section, and a turning section; airflow flows from the intake port through the intake section, the effective section, and the turning section, and then flows out through the exhaust port; the turning section consists of stepped guide vanes and at least three small-angle turning structures connected in sequence, the inner walls of the at least three small-angle turning structures are coated with an elastic coating, and air extraction holes are opened on the first and second small-angle turning structures, the extracted gas is sent to the exhaust port through the air extraction guide pipe and flows out.

[0008] Furthermore, the turning section enables the supersonic airflow to change from radial flow to axial flow.

[0009] Furthermore, the turning section has no fewer than three small-angle turning structures, with each stage having an angle not exceeding 30 degrees. The turning radius of each stage is different, and the radius is more than twice the width of the flow channel. Moreover, the turning radius gradually decreases, with the radius being smaller closer to the exhaust port. This allows the airflow to gradually change its direction through multiple turns, avoiding the violent eddies or separation phenomena that may be caused by a single large-angle turn, and reducing energy loss.

[0010] Furthermore, the stepped guide vanes are formed into a smooth spindle shape to reduce frictional losses.

[0011] Furthermore, no less than three levels of small-angle turning structures are integrally machined.

[0012] Furthermore, each small-angle turning structure is equipped with 1-2 stepped guide vanes.

[0013] Furthermore, the material of the elastic coating is a silicone rubber-based composite material or a polyimide-based elastic coating material, which plays a buffering role and improves boundary layer flow separation.

[0014] Furthermore, grooves 2-5 mm deep are etched on the surface of the small-angle turning structure of no less than level 3.

[0015] Furthermore, the diameter of the air extraction hole is 3-10 mm.

[0016] Furthermore, the air extraction guide pipe is a flexible pipe, which facilitates installation and connection.

[0017] Beneficial effects:

[0018] (1) The disc-shaped channel of the present invention is suitable for environments with limited space and facilitates effective connection with magnet equipment.

[0019] (2) The present invention can effectively control the boundary layer flow separation, reduce the resistance in the power generation channel, weaken or eliminate the intensity of single-stage shock waves in the disc channel, realize the efficient turning of airflow in the confined space, and ultimately improve the performance of the magnetohydrodynamic generator. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the planar arrangement of disc-type channels and solenoid-type superconducting magnets in the prior art;

[0021] Figure 2 This is a diagram showing the velocity streamline distribution in the RZ plane of a disc-type channel in the prior art.

[0022] Figure 3 This is a diagram showing the Mach number distribution in the RZ plane of a disk-type disk in the prior art.

[0023] Figure 4 This is a schematic diagram of a disc-shaped channel suitable for confined spaces according to the present invention;

[0024] Figure 5 A schematic diagram showing the correspondence between various levels of guide vanes and small-angle turning structures;

[0025] Figure 6 This is a partial schematic diagram of the turning section;

[0026] The attached diagram is labeled as follows: 1. Inlet section, 2. Effective section, 3. Turning section, 4. Inlet, 5. Exhaust port, 31. Stepped guide vane, 31-1. First-stage guide vane, 31-2. Second-stage guide vane, 31-3. Third-stage guide vane, 32. Small-angle turning structure with no less than 3 stages, 32-1. First-stage small-angle turning structure, 32-2. Second-stage small-angle turning structure, 32-3. Third-stage small-angle turning structure, 33. Elastic coating, 34. Extraction hole, 35. Extraction guide pipe. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0028] like Figure 4 As shown, the disc-shaped channel proposed in this invention, suitable for confined spaces, includes an intake section 1, an effective section 2, and a turning section 3. Airflow enters from the intake port 4, passes through the intake section 1, the effective section 2, and the turning section 3, and exits from the exhaust port 5. The turning section 3 consists of stepped guide vanes 31 and at least three sequentially connected small-angle turning structures 32.

[0029] like Figure 5As shown, the stepped guide vanes 31 correspond to at least three small-angle turning structures 32. The term "stepped" refers to the gradual approach of the stepped guide vanes to the exhaust port 5 along the airflow direction, from the inlet 4 to the outlet 5. For example, the second-stage guide vane 31-2 is axially closer to the exhaust port 5 than the first-stage guide vane 31-1. The first-stage guide vane 31-1 is located at one-third of the radial direction of the first-stage small-angle turning structure 32-1, the second-stage guide vane 31-2 is located at the middle radial direction of the second-stage small-angle turning structure 32-2, and the third-stage guide vane 31-3 is located at two-thirds of the radial direction of the third-stage small-angle turning structure 32-3. An elastic coating 33 is applied to the inner wall of the at least three-stage small-angle turning structures 32. Air extraction holes 34 are opened on the first-stage small-angle turning structure (32-1) and the second-stage small-angle turning structure (32-2). The extracted gas is sent to the exhaust port 5 via the air extraction guide pipe 35 and flows out.

[0030] like Figure 6 As shown, the turning section 3 enables the supersonic airflow to change from radial to axial flow. The turning section 3 has at least three small-angle turning structures 32, with each stage's angle controlled between 20-30 degrees, ideally as close to 20 degrees as possible. The turning radius varies at each stage, being at least twice the width of the flow channel, and decreasing progressively (i.e.,...). Figure 6 In the diagram, R1 is greater than R2, R2 is greater than R3, R1 is the radius of the arc of the first-stage small-angle turning structure 32-1, R2 is the radius of the arc of the second-stage small-angle turning structure 32-2, and R3 is the radius of the arc of the third-stage small-angle turning structure 32-3. The radius is smaller the closer it is to the exhaust port 5, which reduces the intensity of the single-stage shock wave and achieves efficient airflow turning.

[0031] Preferably, the stepped guide vane 31 has a smooth spindle-shaped structure and is integrally processed with at least 3 small-angle turning structures 32 to ensure structural strength. Considering machinability, each small-angle turning structure 32 is used in conjunction with 1-2 stepped guide vanes.

[0032] Preferably, the elastic coating 33 can be a silicone rubber-based composite material or a polyimide-based elastic coating material, etc. Grooves 2-5 mm deep are etched on the surface of the small-angle turning structure 32 (at least level 3) to ensure good bonding between the elastic coating material and the structure, guaranteeing structural strength.

[0033] Preferably, the diameter of the suction holes 34 is 3-10 mm, the number is determined as needed, and they are arranged symmetrically. The suction flow rate is about 1%-3% of the total flow rate.

[0034] Preferably, the air extraction guide pipe 35 has good flexibility for easy installation and connection. Similarly, high-pressure airflow can also be introduced through the guide pipe 35 into the air extraction port 34 and then into the first and second stage small-angle turning structures 32 to achieve a jet effect.

[0035] The working process of a disc-type channel suitable for confined spaces according to the present invention is as follows:

[0036] After the disc-shaped channel is installed, the working fluid airflow enters from the inlet 4, passes through the inlet section 1, the effective section 2, and the turning section 3, and exits from the exhaust port 5. In the effective section 2, the airflow changes from axial to radial and reaches supersonic speed. In the turning section 3, the high-speed airflow is gradually changed direction by the stepped guide vanes 31 and finally exits from the exhaust port 5. A portion of the high-speed airflow impacts the elastic coating 33 on the inner wall of the at least three small-angle turning structures 32, achieving buffering and reducing the impact of the airflow; at the same time, part of the airflow enters the extraction port 34, flows through the extraction guide pipe 35 and merges into the exhaust port 5, and finally exits. This reduces the adverse pressure gradient on the at least three small-angle turning structures 32, thereby controlling the boundary layer flow separation and weakening the intensity of the single-stage shock wave. It can achieve efficient turning in a confined space, reduce losses, and ultimately improve the performance of the disc generator.

[0037] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A disc-shaped channel suitable for confined spaces, characterized in that, It includes an intake section (1), an effective section (2), and a turning section (3); the airflow flows out from the intake port (4) through the intake section (1), the effective section (2), and the turning section (3) and then out through the exhaust port (5); the turning section (3) consists of a stepped guide vane (31) and at least three small-angle turning structures (32) connected in sequence. The inner wall of the at least three small-angle turning structures (32) is covered with an elastic coating (33). There are air extraction holes (34) on the first small-angle turning structure (32-1) and the second small-angle turning structure (32-2). The extracted gas is sent to the exhaust port (5) through the air extraction guide pipe (35) and flows out.

2. The disc-shaped channel suitable for confined spaces according to claim 1, characterized in that, The confined space refers to the space where the disc channel is installed, and the turning section (3) enables the supersonic airflow to change from radial flow to axial flow.

3. The disc-shaped channel suitable for confined spaces according to claim 1, characterized in that, The turning section (3) has no less than 3 levels of small-angle turning structures (32), each level of which has an angle of no more than 30 degrees. The turning radius of each level is different, and the radius is more than twice the width of the flow channel. The turning radius shows a trend of decreasing step by step, that is, the closer to the exhaust port (5), the smaller the radius.

4. The disc-shaped channel suitable for confined spaces according to claim 1, characterized in that, The stepped guide vane (31) has a smooth spindle-shaped structure.

5. The disc-shaped channel suitable for confined spaces according to claim 1, characterized in that, Small-angle turning structures of no less than level 3 (32) are integrally processed.

6. The disc-shaped channel suitable for confined spaces according to claim 1, characterized in that, Each small-angle turning structure (32) is equipped with 1-2 stepped guide vanes.

7. The disc-shaped channel suitable for confined spaces according to claim 1, characterized in that, The material of the elastic coating (33) is a silicone rubber-based composite material or a polyimide-based elastic coating material.

8. The disc-shaped channel suitable for confined spaces according to claim 1, characterized in that, A groove 2-5 mm deep is etched on the surface of a small-angle turning structure (32) of not less than level 3.

9. The disc-shaped channel suitable for confined spaces according to claim 1, characterized in that, The diameter of the air extraction port (34) is 3-10 mm.

10. The disc-shaped channel suitable for confined spaces according to claim 1, characterized in that, The air extraction guide pipe (35) is a flexible pipe, which is easy to install and connect.

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