Structure and method for decoupling pipeline system bypass pipeline flow acoustic resonance

Abstract

The invention discloses a structure and method for decoupling pipeline system bypass pipeline flow acoustic resonance, a branch pipe is connected to the pipe wall of a main pipeline to form a three-way pipe structure, one ends of a plurality of bypass pipelines are communicated to the branch pipe, the other ends of the bypass pipelines extend respectively, and the tail ends of the bypass pipelines are closed. The vortex at the joint of the main pipeline and the branch pipeline falls off to generate the pressure pulsation frequency, if the acoustic cavity modal frequency of the branch pipelines is coupled with the pressure pulsation frequency to cause flow acoustic resonance, the communicating pipeline is additionally arranged to communicate the two branch pipelines, so that the acoustic cavity modal frequency of the branch pipelines is changed, and the acoustic cavity modal frequency of the branch pipelines is changed. And the acoustic cavity modal frequency is far away from the pressure pulsation frequency, and decoupling is carried out. And therefore, noise elimination and vibration reduction of a pipeline system can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of pipeline systems, and in particular to a structure and method for decoupling flow-acoustic resonance of a branch pipeline of a pipeline system. Background Art

[0002] In the piping system, a branch pipe is branched out in the middle of the main pipe to form a T-shaped three-way pipe structure, and then multiple side pipes are branched out from the branch pipe, so that part of the fluid in the main pipe is diverted from the branch pipe to each side pipe, realizing the diversion and transmission of the fluid. This structure is very common.

[0003] In the above structure, when the fluid in the main pipe flows through the T-shaped connection between the main pipe and the branch pipe, periodic shed vortices will be generated due to flow separation. The shed vortices act as fluid excitation, causing pressure pulsation in the branch pipe. The pressure pulsation frequency matches the vortex shedding frequency. If the pressure pulsation frequency is coupled with the acoustic cavity modal frequency inherent in the branch pipe, it will cause flow acoustic resonance, causing abnormal vibration of the pipeline.

[0004] Therefore, in the above-mentioned pipeline system, the problem of how to suppress flow sound resonance and achieve noise reduction and vibration reduction of the pipeline system remains to be solved. Summary of the invention

[0005] The purpose of the present invention is to provide a structure and method for decoupling the flow-acoustic resonance of a branch pipe of a pipeline system, and to solve the technical problem of how to suppress the flow-acoustic resonance and achieve noise reduction and vibration reduction of the pipeline system.

[0006] To achieve the above-mentioned purpose, the solution of the present invention is: a structure for decoupling the flow-acoustic resonance of a bypass pipeline of a pipeline system, comprising a main pipeline, a bypass pipeline and a connecting pipeline; The main pipe is used to transmit fluid, and a branch pipe is connected to the pipe wall of the main pipe to form a three-way pipe structure; At least two side branch pipelines are provided, one end of each side branch pipeline is connected to the branch pipe, and the other end is extended and closed, so that the fluid in the main pipeline can flow into the branch pipe and then be diverted to each side branch pipeline; At least one connecting pipeline is provided, one end of the connecting pipeline is connected to the pipe wall of one side branch pipeline, and the other end of the connecting pipeline is connected to the pipe wall of another side branch pipeline, so that the two side branch pipelines are connected through the connecting pipeline.

[0007] Furthermore, the side branch pipeline has two parts, namely a main side branch pipeline and a side branch pipeline. The main side branch pipeline is formed by extending forward from one end of the branch pipe away from the main pipe, and the side branch pipeline is connected to the pipe wall of the branch pipe.

[0008] Furthermore, the connecting pipeline is provided with one end connected to the pipe wall of the main branch pipeline and the other end connected to the pipe wall of the secondary branch pipeline.

[0009] A method for decoupling flow acoustic resonance of a branch pipe of a pipeline system is used in a pipeline system, wherein the pipeline system comprises a main pipeline and a branch pipeline; the main pipeline is used to transmit fluid, and a branch pipe is connected to the pipe wall of the main pipeline to form a three-way pipe structure; at least two branch pipelines are provided, one end of each branch pipeline is connected to the branch pipe, and the other end is extended and closed, so that the fluid in the main pipeline can be diverted to each branch pipeline after entering the branch pipe; The method adds a connecting pipeline, wherein at least one connecting pipeline is provided, so that one end of the connecting pipeline is connected to the pipe wall of a side branch pipeline, and the other end is connected to the pipe wall of another side branch pipeline, so that the two side branch pipelines are connected, and the resonance of the pipeline system is reduced by changing the system acoustic mode of the side branch pipeline so that the acoustic cavity modal frequency of the side branch pipeline is offset from the pressure pulsation frequency.

[0010] Furthermore, the connecting position of the connecting pipeline on the two side branch pipelines, and / or the length of the connecting pipeline, and / or the diameter of the connecting pipeline, and / or the extension path of the connecting pipeline are adjusted to change the system acoustic mode of the side branch pipeline, and then change the acoustic cavity modal frequency of the side branch pipeline until the acoustic cavity modal frequency of the side branch pipeline is offset from the pressure pulsation frequency.

[0011] A method for decoupling flow-acoustic resonance of a side branch pipeline of a pipeline system, the method comprising the following steps: S1. Use modeling software to establish a three-dimensional structural model of the pipeline system, the pipeline system includes a main pipeline and a branch pipeline; the pipe wall of the main pipeline is connected to a branch pipe to form a three-way pipe structure; at least two branch pipelines are provided, one end of each branch pipeline is connected to the branch pipe, and the other end is extended separately, and the end of each branch pipeline is closed, so that the fluid in the main pipeline can be diverted to each branch pipeline after entering the branch pipe; S2. Based on the established three-dimensional structural model, the pressure pulsation frequency range of the bypass pipeline near the connection between the main pipeline and the branch pipeline is determined through fluid dynamics simulation; S3, performing acoustic transfer characteristic analysis on the pipeline system, calculating the inherent acoustic frequency characteristics of the closed bypass pipeline, and identifying the acoustic cavity modal frequency range coupled with the pressure pulsation frequency; S4. If there is coupling between the pressure pulsation frequency and the acoustic cavity modal frequency, a connecting pipeline is added in the downstream area of ​​the side branch pipeline, and the connecting pipeline connects the two side branch pipelines; S5. Taking the connection position and diameter of the connecting pipeline as design variables, the connection position and diameter of the connecting pipeline are optimized and adjusted to make the acoustic cavity modal frequency away from the pressure pulsation frequency, thereby realizing flow-acoustic resonance decoupling. Furthermore, the side branch pipelines have two, namely a main side branch pipeline and a secondary side branch pipeline. The main side branch pipeline continues to extend forward from one end of the branch pipe away from the main pipeline to form the main side branch pipeline, and the secondary side branch pipeline is connected to the pipe wall of the branch pipe; the connecting pipeline is provided with one end, one end of which is connected to the pipe wall of the main side branch pipeline, and the other end is connected to the pipe wall of the secondary side branch pipeline.

[0012] Furthermore, in step S2, the fluid dynamics simulation adopts a detached eddy simulation method, and a monitoring plane is set on the side of the bypass pipeline, close to the connection between the main pipeline and the branch pipeline, to capture the pressure pulsation spectrum characteristics.

[0013] Furthermore, in step S3, the acoustic transfer characteristic analysis sets the acoustic modal boundary conditions through the acoustic simulation software, simulates the main pipeline with infinitely long upstream and downstream pipelines, and calculates the acoustic modal frequencies of the closed branch pipelines.

[0014] Furthermore, in step S5, the Box-Behnken experimental design method is used to optimize the connection position and diameter of the connecting pipe, and a response surface model is constructed through polynomial fitting. The optimization goal is to maximize the interval between the acoustic cavity modal frequency and the pressure pulsation frequency.

[0015] After adopting the above scheme, the beneficial effect of the present invention is that a branch pipe is connected to the pipe wall of the main pipe to form a three-way pipe structure, and multiple side pipes are connected to the branch pipe at one end and extend at the other end. In the pipeline system with closed ends, vortex shedding at the connection between the main pipe and the branch pipe dominates the pressure pulsation frequency. If the acoustic cavity modal frequency of the side pipe is coupled with the pressure pulsation frequency to cause flow acoustic resonance, the acoustic cavity modal frequency of the side pipe is changed by adding a connecting pipe to connect the two side pipes, so that the acoustic cavity modal frequency is away from the pressure pulsation frequency, decoupling is performed, so as to achieve sound absorption and vibration reduction of the pipeline system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of a pipeline system in which two bypass pipelines and one connecting pipeline are provided for the present invention; Figure 2 It is the pressure pulsation spectrum diagram of the monitoring plane; Figure 3 A schematic diagram of the arrangement of detection points for a pipeline system with two bypass pipelines; Figure 4 This is the natural acoustic frequency diagram of the piping system with two bypass pipes before the connecting pipe is set up; Figure 5 This is the natural acoustic frequency diagram of a piping system with two bypass pipes after a connecting pipe is set up.

[0017] Explanation of numbers: 1-main pipeline, 2-bypass pipeline, 3-connecting pipeline, 4-branch pipeline, 5-main bypass pipeline, 6-secondary bypass pipeline. DETAILED DESCRIPTION

[0018] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] In the claims, specification and the above-mentioned drawings of the present invention, unless otherwise explicitly defined, directional words, such as the use of terms such as "center", "lateral", "longitudinal", "horizontal", "vertical", "top", "bottom", "inside", "outside", "up", "down", "front", "back", "left", "right", "clockwise", "counterclockwise" and the like to indicate directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation or be constructed and operated in a specific orientation, so it cannot be understood as limiting the specific protection scope of the present invention.

[0020] A structure for decoupling the flow-acoustic resonance of a branch pipe in a pipeline system, combined with Figure 1 , Figure 2 As shown, it includes a main pipeline 1, a side branch pipeline 2 and a connecting pipeline 3; the main pipeline 1 is used to transmit fluid, and the transmitted fluid is specifically liquid in this embodiment, of course, it can also be gas, without specific limitation, and the pipe wall of the main pipeline 1 is connected with a branch pipe 4 to form a T-shaped three-way pipe structure, and specifically in this embodiment, the branch pipe 4 is perpendicular to the main pipeline 1; at least two side branch pipelines 2 are provided, one end of each side branch pipeline 2 is connected to the branch pipe 4, and the other end is extended separately, and the end is closed. The closure mentioned here refers to being closed under normal conditions. Of course, the side branch pipeline 2 can also be connected to a valve, which can release the fluid when the valve is opened. The present application does not consider the change of the acoustic cavity mode of the side branch pipeline due to the opening of the valve. state, the fluid in the main pipeline 1 can enter the branch pipe 4 and then be diverted to each side pipeline 2; at least one connecting pipeline 3 is provided, that is, the connecting pipeline 3 is provided on the side pipeline 2 that generates flow acoustic resonance, one end of the connecting pipeline 3 is connected to the pipe wall of one side pipeline 2, and the other end is connected to the pipe wall of another side pipeline 2, so that the two side pipelines 2 are connected through the connecting pipeline 3. The connecting position of the connecting pipeline 3 is not specifically limited, as long as the acoustic cavity mode is changed by adding the connecting pipeline 3, the acoustic cavity modal frequency of the side pipeline 2 can be decoupled from the pressure pulsation frequency of the fluid therein. Those skilled in the art can determine it according to the specific shape of the pipeline system and the specific state of the fluid transmitted therein.

[0021] More specifically, in this embodiment, the bypass pipeline 2 has two, namely, a main bypass pipeline 5 and a secondary bypass pipeline 6. The main bypass pipeline 5 is formed by extending forward from one end of the branch pipe 4 away from the main pipeline 1, that is, the main bypass pipeline 5 and the branch pipe 4 are actually the front and rear sections of a pipe, and the secondary bypass pipeline 6 is connected to the pipe wall of the branch pipe 4. More specifically, the main bypass pipeline 5 and the branch pipe 4 extend in a straight line, and the secondary bypass pipeline 6 is parallel to the two. The connecting pipeline 3 is provided with one end connected to the pipe wall of the main bypass pipeline 5 and the other end connected to the pipe wall of the secondary bypass pipeline 6, and the connection is the position of the downstream of the main bypass pipeline 5 and the secondary bypass pipeline 6 near the end closure. The bypass pipeline can make the sound pressure offset each other to a certain extent, change the acoustic cavity mode of the main bypass pipeline 5 and the secondary bypass pipeline 6, so as to change the natural acoustic frequency of the two.

[0022] A method for decoupling the flow-acoustic resonance of a branch pipe in a pipeline system, combined with Figure 1-5 As shown, it is used in a pipeline system, and the pipeline system includes a main pipeline 1 and a side pipeline 2; the main pipeline 1 is used to transmit fluid, and the pipe wall of the main pipeline 1 is connected to a branch pipe 4 to form a three-way pipe structure; there are at least two side pipelines 2, one end of each side pipeline 2 is connected to the branch pipe 4, and the other end is extended separately, and the end is closed, so that the fluid in the main pipeline 1 can be diverted to each side pipeline 2 after entering the branch pipe 4; this method is achieved by adding a connecting pipeline 3, and at least one connecting pipeline 3 is provided, so that one end of the connecting pipeline 3 is connected to the pipe wall of one side pipeline 2, and the other end is connected to the pipe wall of another side pipeline 2, so that the two side pipelines 2 are connected, so as to change the system acoustic mode of the side pipeline 2, so that the acoustic cavity modal frequency of the side pipeline 2 is staggered from the pressure pulsation frequency, thereby reducing the resonance of the pipeline system. Specifically, the system acoustic mode of the side branch pipeline 2 can be changed by adjusting the connecting position of the connecting pipeline 3 on the two side branch pipelines 2, and / or the length of the connecting pipeline 3, and / or the diameter of the connecting pipeline 3, and / or the extension path of the connecting pipeline 3, and then changing the acoustic cavity modal frequency of the side branch pipeline 2 until the acoustic cavity modal frequency of the side branch pipeline 2 is offset from the pressure pulsation frequency.

[0023] In order to facilitate the design of the bypass pipeline 2, the method specifically includes the following steps: S1. Use modeling software to establish a three-dimensional structural model of the pipeline system. The modeling software used in this embodiment is Pro / E. Of course, it is also completed using other commonly used modeling software in the field such as UG or SolidWorks. As mentioned above, the pipeline system includes a main pipeline 1 and a side branch pipeline 2; the pipe wall of the main pipeline 1 is connected to a branch pipe 4 to form a three-way pipe structure; there are at least two side branch pipelines 2, one end of each side branch pipeline 2 is connected to the branch pipe 4, and the other end is extended separately, and the end of each side branch pipeline 2 is closed, and the fluid in the main pipeline 1 can be diverted to each side branch pipeline 2 after entering the branch pipe 4, and in this embodiment, the specific pipeline system structure is taken as an example of the specific structure of setting two side branch pipelines 2 and a connecting pipeline 3 in the previous decoupling pipeline system side pipe flow acoustic resonance structure, which will not be repeated here. Of course, this specific embodiment is not intended to limit the scope of protection of the present invention; S2. Based on the established three-dimensional structural model, the pressure pulsation frequency range of the bypass pipeline 2 near the connection between the main pipeline 1 and the branch pipe 4 is determined by fluid dynamics simulation. More specifically, in step S2, the established three-dimensional structural model is imported into the ICEMCFD software, and a grid model of the pipeline system is established by the ICEMCFD software, and then imported into the Fluent software, boundary conditions and fluid parameters are set, and the detached eddy simulation method is used to perform the fluid dynamics simulation, and the monitoring plane is set on the side of the bypass pipeline 2, near the connection between the main pipeline 1 and the branch pipe 4 (i.e. Figure 2 The monitoring plane plane-z1000 shown in FIG. 1 is used to capture the spectral characteristics of the pressure pulsation. The spectral characteristics in this embodiment are shown in FIG. Figure 2 , it can be seen that the second-order frequency of the pressure pulsation at the monitoring surface of the bypass pipeline is around 32-35Hz; S3, perform acoustic transfer characteristic analysis on the pipeline system, calculate the inherent acoustic frequency characteristics of the closed bypass pipeline 2, and identify the acoustic cavity modal frequency range coupled with the pressure pulsation frequency; in a more specific S3 step, the acoustic transfer characteristic analysis is achieved by setting the acoustic modal boundary conditions through the acoustic simulation software, simulating that the main pipeline 1 has infinitely long upstream and downstream pipelines, and calculating the acoustic modal frequency of the closed bypass pipeline. The specific analysis is as follows: the excitation source of the acoustic response considered in the present invention is vortex shedding, which occurs at the three-way position at the junction of the main pipeline and the branch pipe, and does not come from the inlet or outlet of the main pipeline. Therefore, the processing of the boundary conditions of the inlet and outlet of the main pipeline is similar to the full sound absorption boundary conditions in the transfer characteristics. It is set as the pipeline acoustic modal boundary condition in the Actran software to simulate the existence of long upstream and downstream pipelines outside the pipeline boundary, and then use Hypermesh software to mesh the model in which the main bypass pipeline and the secondary bypass pipeline are not connected, and the mesh model is imported into the acoustic simulation software Actran and the boundary conditions and fluid parameters are set. Figure 3This is a simplified schematic diagram of the pipeline measurement point arrangement. Figure 4 : is the natural acoustic frequency diagram of the downstream area of ​​the end of the bypass pipeline without a connected pipeline. It can be seen that the second-order response frequency is 34 Hz, which is close to the second-order frequency of the pressure pulsation in S2. That is, in this specific embodiment, the pressure pulsation frequency in the bypass pipeline 2 is coupled with the acoustic cavity modal frequency, resulting in flow acoustic resonance; S4. If there is coupling between the pressure pulsation frequency and the acoustic cavity modal frequency, a connecting pipeline 3 is added in the downstream area of ​​the bypass pipeline, and the connecting pipeline 3 connects the two bypass pipelines 2; that is, the bypass pipeline 2 is added to the three-dimensional structural model of the pipeline system; S5. Taking the connecting position and diameter of the connecting pipe 3 as design variables, optimizing and adjusting the connecting position and diameter of the connecting pipe, making the acoustic cavity modal frequency away from the pressure pulsation frequency, and realizing flow-acoustic resonance decoupling; specifically, adopting the Box-Behnken experimental design method, optimizing and adjusting the connecting position and diameter of the connecting pipe 3, constructing a response surface model through polynomial fitting, taking the combination conditions of the two variables of the connecting position and the diameter as variable input, using the response surface optimization module of the Design Expret10 software, drawing a response surface diagram, and then selecting the best combination of the two variables according to the response surface diagram, so as to maximize the interval between the acoustic cavity modal frequency and the pressure pulsation frequency. For the inherent acoustic spectrum diagram of the pipeline system with and without a connecting pipe in this embodiment, see Figure 4 , Figure 5 shown.

[0024] The above description is only a preferred embodiment of the present invention and is not a limitation on the design of this case. Any equivalent changes made based on the design key of this case shall fall within the protection scope of this case.

Claims

1. A structure for decoupling the flow-acoustic resonance of a branch pipe of a pipeline system, characterized in that: It comprises a main pipeline (1), a branch pipeline (2) and a connecting pipeline (3); The main pipe (1) is used to transmit fluid, and a branch pipe (4) is connected to the pipe wall of the main pipe (1) to form a three-way pipe structure; At least two side branch pipelines (2) are provided, one end of each side branch pipeline (2) is connected to the branch pipe (4), and the other end is extended and closed, so that the fluid in the main pipeline (1) can flow into each side branch pipeline (2) after entering the branch pipe (4); At least one connecting pipeline (3) is provided, one end of the connecting pipeline (3) is connected to the pipe wall of one side branch pipeline (2), and the other end is connected to the pipe wall of another side branch pipeline (2), so that the two side branch pipelines (2) are connected through the connecting pipeline (3).

2. A structure for decoupling flow-acoustic resonance of a bypass pipe of a pipeline system as claimed in claim 1, characterized in that: The side branch pipeline (2) has two parts, namely a main side branch pipeline (5) and a secondary side branch pipeline (6). The main side branch pipeline (5) extends forward from one end of the branch pipe (4) away from the main pipe (1) to form the main side branch pipeline (5). The secondary side branch pipeline (6) is connected to the pipe wall of the branch pipe (4).

3. A structure for decoupling the flow-acoustic resonance of a branch pipe of a pipeline system as claimed in claim 2, characterized in that: The connecting pipeline (3) is provided with one end connected to the pipe wall of the main branch pipeline (5) and the other end connected to the pipe wall of the secondary branch pipeline (6).

4. A method for decoupling flow acoustic resonance of a side branch pipeline of a pipeline system, characterized in that: Used in a pipeline system, the pipeline system comprises a main pipeline (1) and a branch pipeline (2); the main pipeline (1) is used to transmit fluid, and the pipe wall of the main pipeline (1) is connected to a branch pipe (4) to form a three-way pipe structure; at least two side pipelines (2) are provided, one end of each side pipeline (2) is connected to the branch pipe (4), and the other end is extended and the end is closed, so that the fluid in the main pipeline (1) can enter the branch pipe (4) and then be divided into each side pipeline (2); The method comprises adding a connecting pipeline (3), wherein at least one connecting pipeline (3) is provided, so that one end of the connecting pipeline (3) is connected to the pipe wall of one side branch pipeline (2), and the other end is connected to the pipe wall of another side branch pipeline (2), so that the two side branch pipelines (2) are connected, so that the system acoustic mode of the side branch pipeline (2) is changed, so that the acoustic cavity mode frequency of the side branch pipeline (2) is offset from the pressure pulsation frequency, thereby reducing the resonance of the pipeline system.

5. A method for decoupling flow-acoustic resonance of a bypass pipe in a pipeline system as claimed in claim 4, characterized in that: The connecting position of the connecting pipeline (3) on the two side branch pipelines (2), and / or the length of the connecting pipeline (3), and / or the diameter of the connecting pipeline (3), and / or the extension path of the connecting pipeline (3) are adjusted to change the system acoustic mode of the side branch pipeline (2), thereby changing the acoustic cavity modal frequency of the side branch pipeline (2) until the acoustic cavity modal frequency of the side branch pipeline (2) is offset from the pressure pulsation frequency.

6. A method for decoupling the flow acoustic resonance of a bypass pipe in a pipeline system, characterized in that: The method comprises the following steps: S1. Using modeling software to establish a three-dimensional structural model of a pipeline system, the pipeline system includes a main pipeline (1) and a branch pipeline (2); the pipe wall of the main pipeline (1) is connected to a branch pipe (4) to form a three-way pipe structure; at least two branch pipelines (2) are provided, one end of each branch pipeline (2) is connected to the branch pipe (4), and the other end is extended separately, and the end of each branch pipeline (2) is closed, so that the fluid in the main pipeline (1) can be diverted to each branch pipeline (2) after entering the branch pipe (4); S2. Based on the established three-dimensional structural model, determine the pressure pulsation frequency range of the bypass pipeline (2) near the connection between the main pipeline (1) and the branch pipeline (4) through fluid dynamics simulation; S3, performing an acoustic transfer characteristic analysis on the pipeline system, calculating the inherent acoustic frequency characteristics of the closed bypass pipeline (2), and identifying the acoustic cavity modal frequency range coupled with the pressure pulsation frequency; S4. If there is coupling between the pressure pulsation frequency and the acoustic cavity modal frequency, a connecting pipeline (3) is added in the downstream area of ​​the side branch pipeline, and the connecting pipeline (3) connects the two side branch pipelines (2); S5. Using the connection position and diameter of the connecting pipeline (3) as design variables, the connection position and diameter of the connecting pipeline are optimized and adjusted so that the acoustic cavity modal frequency is far away from the pressure pulsation frequency, thereby achieving flow-acoustic resonance decoupling.

7. A method for decoupling flow acoustic resonance of a bypass pipe of a pipeline system as claimed in claim 6, characterized in that: The side branch pipeline (2) has two parts, namely a main side branch pipeline (5) and a secondary side branch pipeline (6). The main side branch pipeline (5) is formed by extending forward from one end of the branch pipeline (4) away from the main pipeline (1), and the secondary side branch pipeline (6) is connected to the pipe wall of the branch pipeline (4). The connecting pipeline (3) is provided with one end, one end of which is connected to the pipe wall of the main side branch pipeline (5) and the other end of which is connected to the pipe wall of the secondary side branch pipeline (6).

8. A method for decoupling flow acoustic resonance of a bypass pipe of a pipeline system as claimed in claim 6, characterized in that: In step S2, the fluid dynamics simulation adopts a detached eddy simulation method, and a monitoring plane is set on the side of the bypass pipeline (2), close to the connection between the main pipeline (1) and the branch pipeline (4), for capturing the pressure pulsation spectrum characteristics.

9. A method for decoupling flow acoustic resonance of a bypass pipe of a pipeline system as claimed in claim 6, characterized in that: In step S3, the acoustic transfer characteristics analysis sets the acoustic modal boundary conditions through the acoustic simulation software, simulates the main pipeline (1) with infinitely long upstream and downstream pipelines, and calculates the acoustic modal frequencies of the closed branch pipeline.

10. A method for decoupling flow acoustic resonance of a bypass pipe of a pipeline system as claimed in claim 6, characterized in that: In step S5, the Box-Behnken experimental design method is used to optimize the connection position and diameter of the connecting pipe (3), and a response surface model is constructed through polynomial fitting. The optimization goal is to maximize the interval between the acoustic cavity modal frequency and the pressure pulsation frequency.

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