Supersonic airflow generator structure for enhancing pneumatic conveying

Abstract

The invention relates to the field of supersonic spray pipes, in particular to a supersonic airflow generator structure for enhancing pneumatic conveying, which comprises a supersonic spray pipe connected to a supplementing structure, and the supersonic spray pipe is sequentially provided with a spray pipe inlet, a spray pipe reducing section, a spray pipe throat part and a spray pipe outlet in a direction gradually away from an air supplementing structure; the spray pipe inlet is arranged in a straight cylinder mode, a plurality of antifriction pits are formed in the inner wall of the spray pipe inlet, each antifriction pit is arranged in a regular hexagon mode, the multiple antifriction pits are evenly distributed along the inner wall of the spray pipe inlet, and every two adjacent antifriction pits abut against each other. The spray pipe reducing section is arranged in a conical pipe shape, the divergence angle of the spray pipe reducing section is any numerical value between 8 degrees and 12 degrees, and the contraction angle of the spray pipe reducing section is any numerical value between 30 degrees and 60 degrees; the blowing effect of a conventional air supply structure on the solid particle materials is improved.

Description

Technical Field

[0001] The invention relates to the technical field of supersonic nozzles, and in particular to a supersonic airflow generator structure for enhancing pneumatic conveying. Background Art

[0002] The core part of the supersonic airflow generator structure is the supersonic nozzle, which is based on the Bernoulli principle and Huygens principle, also known as the converging and diverging nozzle. It is a tubular structure that contracts in the middle and is asymmetric hourglass-shaped. The supersonic nozzle is mainly composed of two conical tubes and a throat. The front half is a section that contracts from large to small toward the middle. After contracting to a certain extent, it expands outward from small to large through the throat. This kind of pipeline can change the speed of the airflow due to the change of the cross-sectional area of ​​the nozzle, so that the airflow changes from subsonic to sonic, and then accelerates to transonic speed. This type of structure has been widely used as a nozzle for steam turbines and rocket engines, and can also be seen in supersonic jet engines. Similar flow properties have been applied to jets in astrophysics.

[0003] During pneumatic conveying, solid powder or granular materials in the pipeline are prone to sedimentation and blockage, which seriously affects the reliability and safety of the pipeline conveying system. The existing technology usually arranges air supply structures at a certain distance on the conveying pipeline for auxiliary purge, but the outlet air flow velocity of the conventional air supply structure is limited, which directly affects the purge effect. Summary of the invention

[0004] The object of the present invention is to provide a supersonic airflow generator structure for enhancing pneumatic conveying, so as to improve the blowing effect of the conventional air supply structure on the above-mentioned solid particulate materials, so as to solve the problems raised in the above-mentioned background technology.

[0005] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions:

[0006] A supersonic airflow generator structure for enhancing pneumatic conveying comprises a supersonic nozzle connected to a filling structure, wherein the supersonic nozzle is provided with a nozzle inlet, a nozzle reduction section, a nozzle throat and a nozzle outlet in a direction gradually away from the filling structure;

[0007] The nozzle inlet is arranged in a straight cylinder type, and a plurality of friction-reducing depressions are provided on the inner wall of the nozzle inlet, each of which is arranged in a regular hexagonal shape, and the plurality of friction-reducing depressions are evenly distributed along the inner wall of the nozzle inlet, and adjacent friction-reducing depressions abut against each other;

[0008] The nozzle reduction section is arranged in a conical tubular shape, the expansion angle of the nozzle reduction section is any value between 8 degrees and 12 degrees, and the contraction angle of the nozzle gradually contracting section is any value between 30 degrees and 60 degrees;

[0009] The nozzle throat is arranged in a straight cylindrical shape, a throat opening is arranged between the nozzle throat and the nozzle reduction section, the nozzle reduction section is connected with the nozzle throat through the throat opening, and the diameter length of the throat opening is any multiple value between 0.5 times and 1 times the length of the nozzle throat.

[0010] As a preferred embodiment of the present invention, the maximum diameter of each of the friction-reducing depressions is 0.2 mm.

[0011] As a preferred embodiment of the present invention, a nozzle diverging section is arranged between the nozzle outlet and the nozzle throat, the nozzle throat is connected with the nozzle outlet through the nozzle diverging section, the nozzle diverging section is arranged in a conical tubular shape, the smaller end of the nozzle diverging section is connected with the nozzle mouth, and the larger end is connected with the nozzle outlet.

[0012] Beneficial Effects

[0013] The beneficial effects of the present invention are:

[0014] By adding a supersonic nozzle at the end of the air supply structure, a supersonic airflow generator for enhanced pneumatic conveying is obtained, so that when the inlet gas flow of the air supply structure is certain and relatively limited, the outlet airflow of the supersonic airflow generator can be achieved to a supersonic state through special structural design and airflow control, and the strong airflow flow field formed by the nozzle is used to generate turbulent disturbances on the solid particulate materials in the conveying pipeline, especially to generate dynamic scouring on the bottom sedimentary materials, and to form a uniform gas-solid mixture with a certain flow rate again. On the one hand, it solves the problem of limited purge range and blowing and blocking capacity of the existing air supply structure, and on the other hand, it enhances its applicable scope for conveying different types of solid particulate materials, improves its engineering application value, breaks the engineering application limitation that heavy particulate materials are difficult to stably pneumatically convey, and achieves the improvement of the purge effect of conventional air supply structures on the above-mentioned solid particulate materials.

[0015] At the same time, the present invention also has the following advantages

[0016] 1. High outlet flow rate: With a special convergent-expansion structure, the end of the supersonic airflow generator can generate supersonic airflow, and the flow rate gradually decreases along the longitudinal section of the conveying pipeline. Compared with the traditional or single air supply structure, the average airflow velocity is significantly improved.

[0017] 2. Strong adaptability: The conveying structure can be flexibly adjusted according to different material characteristics and conveying environment requirements.

[0018] 3. The system is safe and reliable: The core supersonic nozzle is a mechanical component product, which does not require electronic control components for operation, has accurate movement and no wearing parts.

[0019] 4. Wide range of applications: It is an innovative application in the field of pneumatic conveying system engineering. It can solve the problem of solid particle materials in the pipeline being prone to sedimentation and blockage in existing pneumatic conveying engineering applications, expand the scope of application, and improve the purging effect of conventional air supply structures on the above-mentioned solid particle materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0021] Figure 1 Schematic diagram of supersonic nozzle structure

[0022] Figure 2 A schematic diagram of the structure of a supersonic airflow generator for enhanced pneumatic conveying

[0023] Figure 3 A schematic diagram of the application of a supersonic airflow generator for enhancing pneumatic conveying in a pneumatic conveying process;

[0024] Figure 4 A schematic diagram showing the local structure of the pipe wall at the nozzle inlet;

[0025] Figure 5 It is the curve diagram of throat diameter and flow rate change;

[0026] Figure 6 This is the curve diagram of inlet pressure and outlet Mach number.

[0027] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0028] 1. Supersonic nozzle; 2. Nozzle inlet; 21. Friction reduction depression; 3. Nozzle reduction section; 4. Nozzle throat; 41. Throat; 5. Nozzle expansion section; 6. Nozzle outlet; 7. Air pipe; 8. Air supply structure; 9. Delivery pipeline. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] See also Figure 1-4As shown, a supersonic airflow generator structure for enhancing pneumatic conveying includes a supersonic nozzle connected to a filling structure, the supersonic nozzle is provided with a nozzle inlet 2, a nozzle reduction section 3, a nozzle throat 4 and a nozzle outlet 6 in a direction gradually away from the air supply structure 8, the nozzle outlet 6 is connected to the ash conveying pipeline after being inclined at a certain angle, and a supersonic airflow generator for enhancing pneumatic conveying is obtained by adding a supersonic nozzle at the end of the air supply structure 8, so that when the inlet gas flow rate of the air supply structure 8 is certain and relatively limited, the outlet airflow of the supersonic airflow generator is realized to reach a supersonic state through special structural design and airflow control, and the strong airflow field formed by the nozzle is used to generate turbulent disturbance to the solid particulate material in the conveying pipeline 9, especially to generate dynamic scouring to the bottom sedimentary material, and to form a uniform gas-solid mixture with a certain flow rate again.

[0031] The nozzle inlet 2 is arranged in a straight cylinder, and a plurality of friction-reducing depressions 21 are provided on the inner wall of the nozzle inlet 2. Each friction-reducing depression 21 is arranged in a regular hexagonal shape, and the plurality of friction-reducing depressions 21 are evenly distributed along the inner wall of the nozzle inlet 2. The maximum diameter of each friction-reducing depression 21 is 0.2 mm. Adjacent friction-reducing depressions 21 abut against each other, and the plurality of friction-reducing depressions 21 can form a golf ball surface shape on the inner wall of the nozzle inlet, thereby reducing the friction force when the gas is input into the supersonic nozzle 1, and satisfying the flow rate of the airflow input into the supersonic nozzle 1.

[0032] The nozzle reduction section 3 is set in a conical tubular shape. When determining the specific size of the nozzle reduction section 3, the selection of the diameter of the nozzle throat 4 and the nozzle outlet 6 is limited by the airflow flow rate (m), so the relevant parameters are calculated using the real gas state equation. The calculation is as follows:

[0033]

[0034] Among them: is the critical velocity, is the critical density, m is the air flow rate, and is the nozzle throat diameter.

[0035] In passing After calculating the nozzle outlet diameter, we get Figure 5 As shown:

[0036] According to the above diagram, the expansion angle of the nozzle reduction section 3 is set to any value between 8 degrees and 12 degrees, the contraction angle of the nozzle tapering section is any value between 30 degrees and 60 degrees, the nozzle throat 4 is set in a straight cylinder shape, a throat 41 is set between the nozzle throat 4 and the nozzle reduction section 3, the nozzle reduction section 3 is connected to the nozzle throat 4 through the throat 41, the nozzle throat 4 has a diameter between 3 mm and 7 mm, and the diameter length of the throat 41 is any multiple value between 0.5 times and 1 times the length of the nozzle throat 4. After actual measurement, the following nozzle inlet 2 pressure and nozzle outlet 6 air flow pressure Mach number change curve is obtained, as shown in Figure 6 As shown:

[0037] As the pressure at the supersonic nozzle inlet 2 gradually increases, the outlet Mach number increases accordingly. It can be seen that when used in pneumatic pipelines to transport materials such as fine fly ash, coarse fly ash or slag, the nozzle back pressure, that is, the ambient pressure in the outlet pipeline, is 0.2MPa (absolute pressure), and the inlet pressure is 0.4MPa (absolute pressure) or even higher, the nozzle outlet 6 airflow can achieve a supersonic state.

[0038] A nozzle diverging section 5 is arranged between the nozzle outlet 6 and the nozzle throat 4. The nozzle throat 4 is connected to the nozzle outlet 6 through the nozzle diverging section 5. The nozzle diverging section 5 is arranged in a conical tubular shape. The smaller end of the nozzle diverging section 5 is connected to the nozzle mouth, and the larger end is connected to the nozzle outlet 6.

[0039] A specific application of this embodiment is:

[0040] Compressed air enters from the air pipe 7 at the top of the air supply structure 8, and is accelerated after flowing through the supersonic nozzle connected to the end of the air supply structure 8 (see Appendix). Figure 2 ), the supersonic airflow generator and the conveying pipeline 9 form a certain angle (the center line of the supersonic airflow generator forms an acute angle with the direction of the fluid medium in the conveying pipeline 9). Under the action of the supersonic airflow generator, a high-speed turbulent flow is formed in a local area of ​​the conveying pipeline 9, and the deposited and blocked materials in the pipeline are swept at a high speed. The airflow and the solid particles are fully mixed, which can ensure that the solid particle materials in the pipeline are effectively pushed forward to flow stably. Ideally, they are transported to the end of the pipeline in the form of a stable embolic flow (attached Figure 3 ).

[0041] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Any changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention should fall within the protection scope of the present invention.

Claims

1. A supersonic airflow generator structure for enhancing pneumatic conveying, comprising a supersonic nozzle connected to a supplementary structure, wherein the supersonic nozzle is provided with a nozzle inlet (2), a nozzle reduction section (3), a nozzle throat (4) and a nozzle outlet (6) in a direction gradually away from the supplementary structure (8); The nozzle inlet (2) is arranged in a straight cylinder type, and a plurality of friction-reducing depressions (21) are provided on the inner wall of the nozzle inlet (2), each of the friction-reducing depressions (21) is arranged in a regular hexagonal shape, and the plurality of friction-reducing depressions (21) are evenly distributed along the inner wall of the nozzle inlet (2), and adjacent friction-reducing depressions (21) abut against each other; The nozzle reduction section (3) is arranged in a conical tubular shape, the expansion angle of the nozzle reduction section (3) is any value between 8 degrees and 12 degrees, and the contraction angle of the nozzle gradually contracting section is any value between 30 degrees and 60 degrees; The nozzle throat (4) is arranged in a straight cylindrical shape, a throat opening (41) is arranged between the nozzle throat (4) and the nozzle reduction section (3), the nozzle reduction section (3) is connected to the nozzle throat (4) through the throat opening (41), and the diameter length of the throat opening (41) is any multiple value between 0.5 times and 1 times the length of the nozzle throat (4).

2. A supersonic airflow generator structure for enhancing pneumatic conveying according to claim 1, characterized in that: The maximum diameter of each of the friction-reducing depressions (21) is 0.2 mm.

3. A supersonic airflow generator structure for enhancing pneumatic conveying according to claim 2, characterized in that: A nozzle expansion section (5) is arranged between the nozzle outlet (6) and the nozzle throat (4), and the nozzle throat (4) is connected to the nozzle outlet (6) through the nozzle expansion section (5). The nozzle expansion section (5) is arranged in a conical tubular shape, and the smaller end of the nozzle expansion section (5) is connected to the nozzle mouth, and the larger end is connected to the nozzle outlet (6).

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