Air flow distribution device and pulverized coal furnace

Abstract

The present invention discloses an airflow distribution device and a pulverized coal furnace using the airflow distribution device. The airflow distribution device includes a main flow pipe, an inner tube, a branch pipe and a flow disturbance assembly. The main flow pipe is provided with an airflow channel running through the main flow pipe. The inner tube is arranged in the main flow pipe and the inner tube is arranged on the outer peripheral side of part of the airflow channel. One end of the inner tube is connected to one end of the main flow pipe, and a set gap is provided between the outer peripheral side of the inner tube and the inner wall of the main flow pipe to limit an annular cavity. The branch pipe extends radially along the main flow pipe, and the branch pipe is connected to the annular cavity so as to be suitable for passing a direct airflow through the annular cavity to the outer peripheral side of the swirling airflow in the inner tube. The flow disturbance assembly is arranged at the connection between the branch pipe and the annular cavity so as to be suitable for disturbing the airflow flowing from the branch pipe into the annular cavity. The airflow distribution device of the embodiment of the present invention has the advantage of being able to evenly organize and distribute the secondary air flow field of the pulverized coal furnace.

Description

Technical Field

[0001] The present invention relates to the technical field of combustion equipment, and in particular to an airflow uniform distribution device and a pulverized coal furnace using the airflow uniform distribution device. Background Art

[0002] Pulverized coal furnaces are boilers that use pulverized coal as fuel. They evenly mix pulverized coal and air before feeding it into the combustion chamber, where the solid fuel burns in a suspended state. These furnaces offer advantages such as rapid and complete combustion, large capacity, high efficiency, adaptability to a wide range of coal types, and ease of control and adjustment. However, conventional pulverized coal furnaces suffer from incomplete combustion of the pulverized coal, resulting in low efficiency. Summary of the Invention

[0003] The present invention is based on the inventor's discovery and understanding of the following facts and problems:

[0004] When secondary air is introduced into the pulverized coal furnace in the related art, the direct airflow and the swirl airflow in the secondary air are unevenly distributed, resulting in uneven organization of the secondary air flow field in the burner, thereby reducing the combustion efficiency of the pulverized coal and high fly ash carbon residue.

[0005] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, an embodiment of the present invention provides an airflow uniform distribution device, which has the advantage of being able to evenly distribute the secondary air flow field of a pulverized coal furnace.

[0006] An embodiment of the present invention further provides a pulverized coal furnace.

[0007] The air flow distribution device of an embodiment of the present invention includes a main flow pipe, in which an air flow channel is provided that passes through the main flow pipe; an inner cylinder, which is arranged in the main flow pipe and the inner cylinder is arranged on the outer peripheral side of a portion of the air flow channel, one end of the inner cylinder is connected to one end of the main flow pipe and a set interval is provided between the outer peripheral side of the inner cylinder and the inner wall of the main flow pipe to limit an annular cavity; a branch pipe, which extends radially along the main flow pipe, and the branch pipe is connected to the annular cavity so as to be suitable for introducing a direct airflow into the outer peripheral side of the swirling airflow in the inner cylinder through the annular cavity; a spoiler component, which is arranged at the connection between the branch pipe and the annular cavity so as to be suitable for disturbing the airflow flowing from the branch pipe into the annular cavity.

[0008] The airflow uniform distribution device according to the embodiment of the present invention has the advantage of being able to evenly organize and distribute the secondary air flow field of the pulverized coal furnace.

[0009] In some embodiments, the airflow distribution device includes a fairing, which extends circumferentially and closed along the outer peripheral side of the inner cylinder. One end of the fairing is arranged on the inner wall of the main flow pipe, and the other end of the fairing extends into the annular cavity to make the airflow in the annular cavity evenly distributed.

[0010] In some embodiments, the fairing includes an annular portion and a support portion, wherein the support portion is connected between the annular portion and the inner wall of the main flow pipe. The annular portion extends coaxially with the main flow pipe and extends in a closed manner along the circumference of the annular cavity.

[0011] In some embodiments, the length of the annular portion gradually increases in a direction away from the branch tube.

[0012] In some embodiments, the spoiler assembly includes a spoiler, one end of which is provided at the connection between the inner cylinder and the main flow pipe, and the other end of the spoiler extends into the annular cavity to disturb the airflow entering the annular cavity.

[0013] In some embodiments, the spoiler has a windward surface, and the windward surface forms an angle with an extension direction of the branch pipe so as to guide the airflow to flow out of the annular cavity from a side close to the branch pipe.

[0014] In some embodiments, the windward surface is a spherical surface, and the geometric center of the windward surface is located on the side of the spoiler facing the inner cylinder.

[0015] In some embodiments, the spoiler assembly includes a spoiler, which is provided at the connection between the branch pipe and the annular cavity, and the spoiler extends along the circumference of the inner cylinder to disturb the airflow entering the annular cavity.

[0016] In some embodiments, a protrusion is provided on a side of the spoiler facing the branch pipe, and the protrusion extends along the axial direction of the spoiler.

[0017] The pulverized coal furnace of the embodiment of the present invention includes an airflow uniform distribution device, which can be the airflow uniform distribution device in any of the above embodiments, and is suitable for uniformly distributing the secondary air flow field of the pulverized coal furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 2 is a schematic cross-sectional view of an air flow distribution device according to an embodiment of the present invention.

[0019] Figure 2 Schematic diagram of airflow distribution device according to an embodiment of the present invention.

[0020] Figure 3 It is a structural schematic diagram of an air flow distribution device according to an embodiment of the present invention.

[0021] Reference numerals:

[0022] Main stream pipe 1; inner tube 2; branch pipe 3;

[0023] Spoiler assembly 4; spoiler 41; spoiler 42; protrusion 421;

[0024] Fairing 5; support portion 51; annular portion 52;

[0025] Annular chamber 01; annular chamber 011; overflow chamber 012. DETAILED DESCRIPTION

[0026] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0027] The following combination Figure 1 、 Figure 2 and Figure 3 An air flow distribution device according to an embodiment of the present invention is described.

[0028] The airflow distribution device according to the embodiment of the present invention includes a main flow pipe 1 , an inner tube 2 , a branch flow pipe 3 and a flow disturbance component 4 .

[0029] An air flow channel is provided in the main flow pipe 1, which passes through the main flow pipe 1. The inner tube 2 is provided in the main flow pipe 1 and is provided on the outer circumference of part of the air flow channel. One end of the inner tube 2 is connected to one end of the main flow pipe 1 and there is a set gap between the outer circumference of the inner tube 2 and the inner wall of the main flow pipe 1 to limit the annular cavity 01.

[0030] Specifically, the main flow pipe 1 extends in the front-to-back direction, and the air flow channel penetrates the main flow pipe 1 in the front-to-back direction. The air flow channel is suitable for the swirl air flow to flow along the main flow pipe 1. Figure 2 The middle b path passes through, the main flow pipe 1 is sleeved on the outer circumference of the inner tube 2, the inner tube 2 and the main flow pipe 1 are coaxially arranged, the rear end of the inner tube 2 is connected to the rear end of the main flow pipe 1, and there is a set gap between the outer wall of the inner tube 2 and the inner wall of the main flow pipe 1. The annular cavity 01 is located on the outer circumference of the inner tube 2 and extends closed along the circumference of the inner tube 2.

[0031] The branch pipe 3 extends along the radial direction of the main pipe 1 and is connected to the annular cavity 01 so as to be suitable for introducing a straight airflow into the outer peripheral side of the swirling airflow in the inner tube 2 through the annular cavity 01 .

[0032] Specifically, the extension direction of the branch pipe 3 is orthogonal to the extension direction of the main pipe 1, and one end of the branch pipe 3 is connected to the annular cavity 01 in the main pipe 1. There is a direct airflow in the branch pipe 3, and the airflow in the branch pipe 3 flows in the form of laminar flow. After passing through the annular cavity 01, the direct airflow in the branch pipe 3 flows into the main pipe 1 along the outer wall of the inner tube 2 and flows along the Figure 2 The path a shown flows to the front side of the main flow pipe 1 and is evenly distributed along the outer peripheral side of the swirling airflow in the inner tube 2, thereby improving the uniformity of the secondary air flow field organization.

[0033] The flow disturbance component 4 is provided at the connection between the branch pipe 3 and the annular cavity 01 so as to disturb the airflow flowing from the branch pipe 3 into the annular cavity 01 .

[0034] Specifically, in the air flow uniform distribution device in the related art, when the branch pipe 3 introduces a direct air flow into the annular cavity 01, under the action of inertia, the direct air flow in the annular cavity 01 accumulates on the side of the annular cavity 01 away from the branch pipe 3, and the direct air flow in the annular cavity 01 flows along the Figure 2 After the path a enters the main flow pipe 1, the direct airflow in the main flow pipe 1 is unevenly distributed.

[0035] The air flow distribution device of the embodiment of the present invention is provided with a turbulent component 4, so that the direct current airflow in the annular cavity 01 is evenly distributed along the circumference of the annular cavity 01. When the direct current airflow in the annular cavity 01 enters the main flow pipe 1 along the outer wall of the inner tube 2, the direct current airflow in the main flow pipe 1 is evenly distributed along the circumference of the main flow pipe 1, so that the direct current airflow flowing out of the air flow distribution device of the embodiment of the present invention is evenly distributed along the circumference of the main flow pipe. When the direct current airflow flowing out to the front side of the air flow distribution device of the embodiment of the present invention is converted into a swirl airflow under the action of the cyclone, the circumferential uniform distribution characteristics of the swirl airflow flowing out of the air flow distribution device of the embodiment of the present invention are increased. When the air flow distribution device of the embodiment of the present invention is used to provide secondary air for a pulverized coal furnace, the flow field organization of the secondary air provided by the air flow distribution device is evenly distributed, thereby improving the efficiency of the pulverized coal furnace during combustion, so that the air flow distribution device of the embodiment of the present invention has the advantage of being able to make the secondary air flow field organization of the pulverized coal furnace evenly distributed.

[0036] In some embodiments, the airflow distribution device includes a fairing 5, which extends circumferentially along the outer peripheral side of the inner tube 2. One end of the fairing 5 is arranged on the inner wall of the main flow pipe 1, and the other end of the fairing 5 extends into the annular cavity 01 to make the airflow in the annular cavity 01 evenly distributed.

[0037] Specifically, the fairing 5 is located on the inner side of the main flow pipe 1 and is sleeved on the outer peripheral side of the inner tube 2. One end of the fairing 5 connected to the inner wall of the main flow pipe 1 extends closed along the circumference of the main flow pipe 1, and the other end of the fairing 5 extends into the annular cavity 01 to separate the annular cavity 01 into a ring flow cavity 011 and an overflow cavity 012. The ring flow cavity 011 is suitable for guiding the air in the branch pipe 3 to be evenly distributed along the annular cavity 01, and the overflow cavity 012 is connected between the ring flow cavity 011 and the air flow channel.

[0038] The circulation chamber 011 is located on the outer peripheral side of the overflow chamber 012, and the branch pipe 3 is connected to the circulation chamber 011. When the direct current airflow in the branch pipe 3 flows into the circulation chamber 011, under the guidance of the fairing 5, the direct current airflow flows along the circulation chamber 011 and is evenly distributed. When the direct current airflow fills the circulation chamber 011, the airflow in the circulation chamber 011 flows from the connection between the circulation chamber 011 and the overflow chamber 012 to the overflow chamber 012, and the direct current airflow flows into the main pipe 1 through the overflow chamber 012.

[0039] Thus, the fairing 5 divides the annular cavity 01 into the annular cavity 011 and the overflow cavity 012, so that the direct airflow flowing from the annular cavity 01 to the main flow pipe 1 is evenly distributed along the circumference of the main flow pipe 1, thereby improving the uniformity of the secondary air flow field organization flowing out from the airflow distribution device of the embodiment of the present invention.

[0040] In some embodiments, the fairing 5 includes an annular portion 52 and a support portion 51 , the support portion 51 is connected between the annular portion 52 and the inner wall of the main flow pipe 1 , the annular portion 52 extends coaxially with the main flow pipe 1 and the annular portion 52 extends in a closed manner along the circumference of the annular cavity 01 .

[0041] Specifically, the support portion 51 is connected to the inner wall of the main flow pipe 1, and the support portion 51 extends in a closed manner along the circumference of the main flow pipe 1. One end of the support portion 51 is connected to the main flow pipe 1, and the other end of the support portion 51 is connected to the annular portion 52. The annular portion 52 is an annular structure. One end of the annular portion 52 is connected to the support portion 51, and the other end of the annular portion 52 extends into the annular cavity 01, and the annular portion 52 extends in a closed manner along the circumference of the main flow pipe 1.

[0042] Thus, the annular portion 52 is coaxially arranged with the main flow pipe 1, so that the thickness of the annular cavity 011 is uniform along the circumference of the main flow pipe 1. Therefore, when the direct flow fills the annular cavity 011 and overflows to the overflow cavity 012, the air pressure in the annular cavity 011 is uniform everywhere, and the airflow overflowing from the annular cavity 011 to the overflow cavity 012 is evenly distributed along the circumference of the main flow pipe 1, thereby making the annular cavity 011 uniform along the circumference of the main flow pipe. Figure 2 The straight airflow flowing in the direction a is evenly distributed along the circumference of the main flow pipe 1, thereby making the flow field organization distribution of the swirl airflow flowing backward through the inner tube 2 more even.

[0043] In some embodiments, the length of the annular portion 52 gradually increases in a direction away from the branch tube 3 .

[0044] Specifically, the length dimension of the annular portion 52 is the dimension of the annular portion 52 extending axially along the main stream pipe 1 at each position. The length dimension of the annular portion 52 close to the branch pipe 3 is smaller, and the length dimension of the annular portion 52 away from the branch pipe 3 is larger, and the length dimension of the annular portion 52 gradually changes.

[0045] Therefore, when the direct current airflow flows from the annular cavity 01 to the main flow pipe 1, the direct current airflow near the branch pipe 3 in the annular cavity 01 is more likely to flow into the main flow pipe 1 and flow out from the front end of the main flow pipe 1, and the direct current airflow in the annular cavity 01 away from the branch pipe 3 is less likely to flow into the main flow pipe 1. Compared with the airflow uniform distribution device in the related art, the direct current airflow flowing from the annular cavity 01 to the main flow pipe 1 in the airflow uniform distribution device of the embodiment of the present invention is more evenly distributed along the circumference of the main flow pipe 1.

[0046] In some embodiments, the spoiler assembly 4 includes a spoiler 41 , one end of which is located at the connection between the inner tube 2 and the main flow pipe 1 , and the other end of the spoiler 41 extends into the annular cavity 01 to disturb the airflow entering the annular cavity 01 .

[0047] Specifically, the spoiler 41 is arranged on the path of the direct airflow in the branch pipe 3 flowing into the annular cavity 01. When the direct airflow in the branch pipe 3 flows into the annular cavity 01, the direct airflow is obstructed by the spoiler 41 and accumulates on the side of the spoiler 41 facing the branch pipe 3.

[0048] Therefore, when the direct current airflow in the branch pipe 3 impacts the spoiler 41, part of the direct current airflow flows into the main pipe 1 under the disturbance of the spoiler 41 and flows out from the front end of the main pipe 1, thereby making the direct current airflow flowing from the annular cavity 01 to the main pipe 1 in the airflow uniform distribution device of the embodiment of the present invention more evenly distributed along the circumference of the main pipe 1, thereby making the flow field organization distribution of the swirl airflow flowing backward through the inner tube 2 more evenly distributed.

[0049] In some embodiments, the spoiler 41 has a windward surface, and the windward surface forms an angle with the extension direction of the branch pipe 3 so as to guide the airflow to flow out of the annular cavity 01 from the side close to the branch pipe 3 .

[0050] Specifically, the side of the spoiler 41 facing the branch pipe 3 is the windward surface of the spoiler 41. When the DC airflow in the branch pipe 3 flows into the annular cavity 01, the DC airflow impacts the windward surface. The windward surface has an inclination angle. The position of the windward surface close to the axis of the branch pipe 3 is farther away from the branch pipe 3, and the position of the windward surface close to the connection between the inner tube 2 and the main pipe 1 is closer to the branch pipe 3.

[0051] Therefore, under the guidance of the windward surface, when the direct current airflow impacts the windward surface, the direct current airflow impacting the windward surface is deflected and flows toward the outlet of the annular cavity 011 close to the branch pipe 3, increasing the airflow at the outlet of the annular cavity 011 close to the branch pipe 3, so that the airflow from the annular cavity 01 along the Figure 2 The straight airflow flowing into the main flow pipe 1 in the direction a is more evenly distributed along the circumference of the main flow pipe 1, thereby making the flow field organization distribution of the swirl airflow flowing backward through the inner tube 2 more even.

[0052] In some embodiments, the windward surface is a spherical surface, and the geometric center of the windward surface is located on the side of the spoiler 41 facing the inner tube 2 .

[0053] Specifically, the windward surface is a spherical surface, that is, the windward surface not only has an inclination angle in the axial direction along the main flow pipe 1, but also has an inclination angle in the circumferential direction along the main flow pipe 1. It should be noted that the inclination angle of the windward surface on one side along the circumferential direction of the main flow pipe 1 is the same as the inclination angle of the windward surface on the other side along the circumferential direction of the main flow pipe 1.

[0054] Therefore, when the DC airflow flowing out of the branch pipe 3 hits the windward surface, under the guidance of the windward surface, part of the DC airflow not only flows along the axial direction of the main pipe 1, but also part of the DC airflow flows along the circumferential direction of the main pipe 1, balancing the resistance of the DC airflow flowing through the spoiler component 4 to the annular cavity 01.

[0055] In some embodiments, the spoiler assembly 4 includes a spoiler 42 , which is provided at the connection between the branch pipe 3 and the annular cavity 01 . The spoiler 42 extends along the circumference of the inner tube 2 to disturb the airflow entering the annular cavity 01 .

[0056] Specifically, the spoiler 42 is provided at the end of the spoiler portion 41, the spoiler 42 is coaxially arranged with the main flow pipe 1, and the spoiler 42 is provided on the path of the direct current airflow provided in the branch pipe 3 flowing into the annular cavity 01. When the direct current airflow in the branch pipe 3 flows into the annular cavity 01, the direct current airflow is obstructed by the spoiler 42 and accumulates on the side of the spoiler 42 facing the branch pipe 3.

[0057] Thus, the air pressure in the annular cavity 01 near the branch pipe 3 is increased, making it easier for the air flow in the annular cavity 01 near the branch pipe 3 to flow along the Figure 2 The air flows into the main flow pipe 1 in the middle a direction and flows out from the front end of the main flow pipe 1, so that the direct airflow flowing from the annular cavity 01 to the main flow pipe 1 in the airflow uniform distribution device of the embodiment of the present invention is more evenly distributed along the circumference of the main flow pipe 1, thereby making the flow field organization distribution of the swirl airflow flowing backward through the inner tube 2 more even.

[0058] In some embodiments, a protrusion 421 is provided on a side of the spoiler 42 facing the branch pipe 3 , and the protrusion 421 extends along the axial direction of the spoiler 42 .

[0059] Specifically, the protrusion 421 is provided at one end of the spoiler 42 facing the branch pipe 3 , the protrusion 421 is similar to the branch pipe 3 , is a strip-shaped structure, and extends along the axial direction of the main pipe 1 .

[0060] Therefore, when the direct airflow in the branch pipe 3 hits the spoiler 42, the protrusion 421 guides part of the direct airflow to flow toward the outlet of the annular cavity 011 near the branch pipe 3, increasing the airflow at the outlet of the annular cavity 011 near the branch pipe 3, making the direct airflow flowing from the annular cavity 01 to the main pipe 1 more evenly distributed along the circumference of the main pipe 1, thereby making the flow field organization distribution of the swirl airflow flowing backward through the inner tube 2 more even.

[0061] In some embodiments, there are two protrusions 421, and the two protrusions 421 are arranged along the Figure 3 As shown in FIG, the symmetrical arrangement of the two airflow paths is shown in FIG. Therefore, when the direct current airflow is disturbed by the spoiler 42 and flows into the annular cavity 01, the direct current airflow in the annular cavity 01 is symmetrically arranged along the left and right directions. The airflow overflowing from the annular cavity 011 into the overflow cavity 012 is evenly distributed along the circumference of the main flow pipe 1, thereby making the direct current airflow in the main flow pipe 1 evenly distributed along the circumference of the main flow pipe 1.

[0062] The following describes a pulverized coal furnace according to an embodiment of the present invention.

[0063] The pulverized coal furnace of the embodiment of the present invention includes an airflow uniform distribution device, which can be the airflow uniform distribution device in any of the above embodiments. The airflow uniform distribution device is suitable for evenly distributing the secondary air flow field of the pulverized coal furnace.

[0064] Specifically, the front side of the air flow distribution device is connected to the cyclone, which makes the air flow along the Figure 2 The direct airflow flowing to the cyclone fan in the direction a changes to the airflow flowing along Figure 2 The rear end of the airflow distribution device is connected to the combustion chamber, along Figure 2 The swirling airflow flowing out of the swirler in direction b flows into the combustion chamber as secondary air.

[0065] Therefore, since the airflow distribution device evenly distributes the direct airflow on the outer peripheral side of the swirl airflow, the flow field organization of the secondary air provided by the airflow distribution device is evenly distributed, thereby improving the efficiency of the pulverized coal furnace during combustion, so that the gas pulverized coal furnace of the embodiment of the present invention has the advantage of even distribution of the secondary air flow field organization.

[0066] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0067] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0068] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0069] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0070] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0071] Although the above embodiments have been shown and described, it is understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those skilled in the art are all within the scope of protection of the present invention.

Claims

1. An air flow distribution device, characterized in that: include: A main flow pipe, wherein the main flow pipe is provided with an air flow channel running through the main flow pipe; an inner cylinder, the inner cylinder being disposed in the main flow pipe and having a length smaller than that of the main flow pipe, one end of the inner cylinder being connected to the downstream end of the main flow pipe, and a set gap being formed between the outer circumference of the inner cylinder and the inner wall of the main flow pipe to define an annular cavity; a branch pipe, the branch pipe being arranged on the outer wall of the main pipe and extending radially along the main pipe, the branch pipe corresponding to the inner cylinder, and being in communication with the annular cavity to allow a direct airflow to enter; when the direct airflow in the annular cavity enters the main pipe along the outer wall of the inner cylinder, the direct airflow in the main pipe is evenly distributed along the circumference of the main pipe, and the direct airflow flowing upstream of the main pipe is converted into a swirling airflow by the action of a cyclone; a flow-disturbing assembly, the flow-disturbing assembly being provided at the connection between the branch pipe and the annular cavity and being adapted to disturb the straight flow flowing from the branch pipe into the annular cavity; A fairing is located on the inner side of the main flow pipe and is sleeved on the outer circumference of the inner cylinder. One end of the fairing is connected to the inner wall of the main flow pipe, and the other end of the fairing extends along the downstream of the main flow pipe to separate the annular cavity into a circulating cavity and an overflow cavity.

2. The air flow distribution device according to claim 1, characterized in that: The fairing includes an annular portion and a supporting portion, wherein the supporting portion is connected between the annular portion and an inner wall of the main flow pipe, and the annular portion extends coaxially with the main flow pipe.

3. The air flow distribution device according to claim 2, characterized in that: The length of the annular portion gradually increases in a direction away from the branch pipe.

4. The air flow distribution device according to claim 2, characterized in that: The flow spoiler assembly includes a flow spoiler, one end of which is arranged at the connection between the inner cylinder and the main flow pipe, and the other end of which extends into the annular cavity to disturb the airflow entering the annular cavity.

5. The air flow distribution device according to claim 4, characterized in that: The spoiler has a windward surface, and the windward surface forms an angle with the extension direction of the branch pipe so as to guide the airflow to flow out of the annular cavity from a side close to the branch pipe.

6. The air flow distribution device according to claim 5, characterized in that: The windward surface is a spherical surface, and the geometric center of the windward surface is located on the side of the spoiler facing the inner cylinder.

7. The air flow distribution device according to claim 4, characterized in that: The spoiler assembly includes a spoiler, which is provided at the connection between the branch pipe and the annular cavity. The spoiler extends along the circumference of the inner cylinder to disturb the airflow entering the annular cavity.

8. The air flow distribution device according to claim 7, characterized in that: A protrusion is provided on a side of the spoiler facing the branch pipe, and the protrusion extends along the axial direction of the spoiler.

9. A pulverized coal furnace, characterized in that: It comprises an air flow uniform distribution device, which is the air flow uniform distribution device according to any one of claims 1 to 8, and is suitable for making the secondary air flow field of the pulverized coal furnace evenly distributed.

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