Apparatus and method for measuring acoustic excitation noise in steam pipeline of nuclear power plant

Abstract

The present invention relates to an apparatus and method for measuring acoustic excitation noise in a steam pipeline of a nuclear power plant. Multiple layers of sound absorption materials are arranged at the end in a shielding cavity close to a bottom side, and a flexible attaching mechanism is arranged at an opening of the shielding cavity; during measurement, the flexible attaching mechanism is attached to the outer wall of a steam pipeline of an nuclear power plant; the multiple layers of sound absorption materials isolate noise in an environment outside the shielding cavity; by means of a through hole, a microphone is placed in the shielding cavity for measurement, implementing non-destructive indirect measurement of noise in the steam pipeline of the nuclear power plant from the outside of the steam pipeline, and realizing the advantages of interference prevention and easy installation; the noise isolation of the shielding cavity and the multiple layers of sound absorption materials and the tight attachment of the flexible attaching mechanism on the pipe wall eliminate the impact of field environments on measurement; and the direct attachment of the shielding cavity to the pipe wall solves the problem that measurement cannot be carried out due to a narrow space size, realizing effective noise tests in high-temperature and high-pressure environments.

Description

Device and method for measuring acoustically excited noise in steam pipes of nuclear power plants

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202310955553.1, filed on July 31, 2023, entitled “A device and method for measuring acoustically excited noise in steam pipes of nuclear power plants,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to the technical field of nuclear steam power generation, and in particular to a device and method for measuring acoustic excitation noise in a steam pipeline of a nuclear power plant. Background Art

[0004] Acoustic resonance in nuclear power plant steam pipelines and equipment causes intense vibration and noise, leading to fatigue damage to valve trim, directly impacting valve function and severely affecting the acoustic environment in the main control room. Research has shown that the high-speed steam flow within the main steam pipeline, formed by the cavities formed by the branch pipes and valve chambers, induces turbulence and vortex shedding at the tees. When the vortex shedding frequency approaches the natural acoustic modal frequency of the valve cavity, the two frequencies lock together, emitting intense vibration and noise simultaneously, a phenomenon known as flow-induced acoustic resonance. Acoustic resonance generates high-intensity acoustic pressure pulsations, which (acoustic loads) propagate along the steam pipelines, causing damage to valve trim due to fretting wear, impacting the normal and stable operation of the nuclear power plant. Furthermore, the high-intensity vibrations generated by acoustic resonance propagate along the pipelines, radiating secondary noise into the main control room, impacting the noise level and causing significant auditory annoyance to staff.

[0005] The inventors discovered that the noise characteristics within the pipeline can be measured by directly placing a microphone within the pipeline. However, the steam in the steam pipeline of a nuclear power plant is high-temperature, high-pressure, and high-flow rate, and the operating temperature range of the microphone is generally within 50°C. Effective noise testing cannot be performed in such a high-temperature and high-pressure environment. In addition, under high-flow conditions, the microphone will generate strong airflow regeneration noise, which seriously affects the measurement results. Therefore, for nuclear power plant steam pipelines, it is impossible to directly place a microphone within the pipeline to measure the noise characteristics. Because steam valve sections in nuclear power plants are typically confined, piping components are tightly packed, and the pipelines are numerous and complex, the walls of the room are often sound-reflecting. Therefore, the noise level at a given point measured directly with a microphone outside a nuclear power plant's steam piping is the sum of the noise radiated from multiple pipes and the reverberation caused by wall reflections. For example, a steam valve section actually contains several pipes, numbered 1 through 5. Due to the confined space and the close proximity of the pipes, the noise measured near pipe 1 includes not only the noise from pipe 1, but also the noise from pipes 2 through 5, as well as significant reverberation. These different noise sources significantly influence each other, making direct microphone measurement of pipe noise ineffective in eliminating the effects of the on-site environment and preventing effective measurement. The confined piping space in nuclear power plants precludes the installation of a separate testing room, and the pipe-based measurement method, which uses a testing room enclosure, is not suitable for nuclear power plant steam piping measurements.

[0006] Summary of the Invention

[0007] In response to the shortcomings of the existing technology, the present invention provides a device and method for measuring acoustically excited noise in the steam pipeline of a nuclear power plant, which realizes non-destructive indirect measurement of noise inside the pipe outside the steam pipeline of a nuclear power plant. It has the advantages of anti-interference and easy installation. The reliability of the method has been confirmed through verification of nuclear power site noise tests.

[0008] A first aspect of the present invention provides an acoustically excited noise measuring device for a steam pipe in a nuclear power plant, comprising: a microphone; a shielding cavity, a side wall of which is provided with a through hole for the microphone to enter the shielding cavity; a multi-layer sound-absorbing material, which is arranged on the inner bottom side of the shielding cavity, the inner bottom side being the end away from the opening of the shielding cavity; a flexible fitting mechanism, which is arranged at the opening of the shielding cavity; wherein the flexible fitting mechanism can be fitted on the outer wall of the steam pipe of the nuclear power plant, the multi-layer sound-absorbing material isolates the noise in the external environment of the shielding cavity, and the microphone is placed in the shielding cavity through the through hole for measurement.

[0009] Preferably, a protective mesh is provided in the shielding cavity, and the multi-layer sound absorbing material is fixed to the inner bottom side of the shielding cavity.

[0010] Preferably, the thickness of each layer of the multi-layer sound absorbing material is different.

[0011] Preferably, the multi-layer sound absorbing material is one or more of a resistive porous sound absorbing structure, a resonant resistant sound absorbing structure and a resistive resistant composite sound absorbing structure.

[0012] Preferably, each layer of the resistive porous sound absorbing structure has a different bulk density, and each layer of the resonant anti-sound absorbing structure has different parameters.

[0013] Preferably, rubber or sponge is provided on the inner side of the flexible fitting mechanism.

[0014] A second aspect of the present invention provides a method for measuring acoustically excited noise within a nuclear power plant steam pipeline. The method uses an acoustically excited noise measuring device within a nuclear power plant steam pipeline for measurement. The measuring device includes a microphone, a shielding cavity having a through hole formed in a side wall, a multilayer sound-absorbing material disposed on the inner bottom side of the shielding cavity, and a flexible fitting mechanism disposed at the opening of the shielding cavity. The method includes the following steps:

[0015] The flexible bonding mechanism is bonded to the outer wall of the steam pipe of the nuclear power plant, and the multi-layer sound-absorbing material isolates the noise in the external environment of the shielding cavity;

[0016] The microphone is placed in the shielded cavity through a through hole for measurement, and the sound pressure level of the external noise of the steam pipeline of the nuclear power plant is obtained.

[0017] Preferably, the method for measuring acoustic excitation noise in a steam pipeline of a nuclear power plant further comprises the following steps:

[0018] Calculate pipeline transmission losses;

[0019] The sound pressure level of the noise inside the pipe is obtained according to the sum of the pipeline transmission loss and the sound pressure level of the noise outside the pipe.

[0020] Preferably, calculating the pipeline transmission loss includes:

[0021] Establishing a pipe sound insulation model based on a transfer matrix method, wherein the pipe sound insulation model includes impedance models of various layers of materials of the steam pipe, wherein the various layers of materials of the steam pipe include a metal layer and an insulation layer of the steam pipe;

[0022] Calculating the acoustic impedance of each layer of material of the steam pipeline;

[0023] The transmission loss of each layer of material of the steam pipe is calculated based on the acoustic impedance.

[0024] Preferably, calculating the acoustic impedance of each layer of material of the steam pipe includes:

[0025] Calculate the acoustic impedance of each metal layer;

[0026] Calculate the acoustic impedance of each insulation layer;

[0027] The surface acoustic impedance of each layer of steam pipeline material is calculated by transfer matrix method.

[0028] The present invention arranges a multi-layer sound-absorbing material near one end of the bottom side in the shielding cavity, and arranges a flexible fitting mechanism at the opening of the shielding cavity; during measurement, the flexible fitting mechanism is fitted on the outer wall of the steam pipe of the nuclear power plant to isolate the noise of the external environment of the shielding cavity, and the microphone is placed in the shielding cavity through the through hole for measurement, thereby realizing non-destructive indirect measurement of the noise inside the pipe outside the steam pipe of the nuclear power plant, and has the advantages of anti-interference and easy installation. The noise isolation between the shielding cavity and the multi-layer sound-absorbing material and the close fitting of the flexible fitting mechanism on the pipe wall eliminate the influence of the on-site environment on the measurement. The shielding cavity is directly fitted on the pipe wall to solve the problem of being unable to perform measurement due to the small space size, thereby realizing effective noise testing in a high temperature and high pressure environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments of the present application.

[0030] FIG1 is a schematic structural diagram of an acoustically excited noise measuring device in a nuclear power plant steam pipeline according to a specific embodiment of the present invention;

[0031] FIG2 is a schematic diagram of a device for measuring acoustic excitation noise in a nuclear power plant steam pipeline according to a specific embodiment of the present invention, attached to the outer wall of the nuclear power plant steam pipeline;

[0032] 3 is a schematic diagram of a device for measuring acoustic excitation noise in a nuclear power plant steam pipeline according to another specific embodiment of the present invention, attached to the outer wall of the nuclear power plant steam pipeline;

[0033] FIG4 is a flow chart of a method for measuring acoustically excited noise in a steam pipe of a nuclear power plant according to a specific embodiment of the present invention;

[0034] FIG5 is a noise spectrum curve measured in the shielding cavity according to the embodiment shown in FIG2 ;

[0035] FIG6 is a frequency spectrum curve of calculating pipeline transmission loss according to the embodiment shown in FIG2 ;

[0036] FIG7 is a comparison diagram of the measured and calculated sound pressure levels in the tube of the embodiment shown in FIG2 ;

[0037] FIG8 is a noise spectrum curve measured in the shielding cavity according to the embodiment shown in FIG3 ;

[0038] FIG9 is a frequency spectrum curve of calculating pipeline transmission loss according to the embodiment shown in FIG3 ;

[0039] FIG10 is a comparison diagram of the measured and calculated sound pressure levels in the tube of the embodiment shown in FIG3 .

[0040] Figure 100 - Acoustically excited noise measuring device for a nuclear power plant steam pipe; 10 - Multi-layer sound-absorbing material; 1 - First sound-absorbing material; 2 - Second sound-absorbing material; 3 - Third sound-absorbing material; 4 - Fourth sound-absorbing material; 5 - Surface protection net; 6 - Through hole; 7 - Flexible fitting mechanism; 8 - Shielding cavity; 81 - Opening; 82 - Bottom side; 9 - Nuclear power plant steam pipe; 91 - Insulation layer; 92 - Metal layer. DETAILED DESCRIPTION

[0041] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0042] FIG1 is a schematic structural diagram of an acoustically excited noise measuring device 100 in a nuclear power plant steam pipeline according to a specific embodiment of the present invention.

[0043] As shown in FIG1 , the device 100 for measuring acoustically excited noise in a steam pipe of a nuclear power plant according to this embodiment includes a microphone (not shown), a shielding cavity 8 , a multi-layer sound absorbing material 10 and a flexible fitting mechanism 7 .

[0044] The shielding cavity 8 is an internal hollow structure having an opening 81 and a bottom side 82 opposite to the opening 81 . The opening 81 and the bottom side 82 are respectively located at two ends of the shielding cavity 8 . A through hole 6 for the microphone to enter the shielding cavity 8 is opened on the side wall of the shielding cavity 8 .

[0045] The multi-layer sound absorbing material 10 is disposed in the shielding cavity 8 near one end of the bottom side 82 to isolate the noise in the external environment of the shielding cavity 8 .

[0046] The flexible fitting mechanism 7 is arranged at the opening 81 of the shielding cavity 8 and is connected to the side wall of the shielding cavity 8. The opening 81 is circular or rectangular. The flexible fitting mechanism 7 surrounds the opening 81 and extends to the outside of the opening 81, and can be fitted on the outer wall of the steam pipe 9 of the nuclear power plant.

[0047] FIG2 is a schematic diagram of a nuclear power plant steam pipe internal acoustic excitation noise measuring device 100 according to a specific embodiment of the present invention attached to the outer wall of a nuclear power plant steam pipe 9 .

[0048] As shown in FIG2 , during measurement, the flexible fitting mechanism 7 is fitted onto the outer wall of the steam pipe 9 of the nuclear power plant. The shielding cavity 8 and the multi-layer sound-absorbing material 10 jointly isolate the noise in the external environment of the shielding cavity 8 . The microphone is placed in the shielding cavity 8 through the through hole 6 for measurement.

[0049] There can be multiple side through holes 6, which are used to place multiple microphones in the shielding cavity 8, and then average the noise values ​​tested by the multiple microphones to obtain the sound pressure level of the noise outside the tube.

[0050] After measuring the sound pressure level of the external noise of the nuclear power plant steam pipe 9 by the measuring device 100, the pipeline transmission loss is calculated according to the pipeline parameters of the nuclear power plant steam pipe 9, and then the pipeline transmission loss is added to the external noise sound pressure level to obtain the internal noise sound pressure level.

[0051] The multi-layer sound-absorbing material 10 isolates the noise in the external environment of the shielding cavity 8. The microphone is placed in the shielding cavity 8 through the through hole 6 for measurement, realizing non-destructive indirect measurement of the noise inside the pipe outside the nuclear power plant steam pipe 9, which has the advantages of anti-interference and easy installation. The noise isolation of the shielding cavity 8 and the multi-layer sound-absorbing material 10 and the close fit of the flexible bonding mechanism 7 on the pipe wall eliminate the influence of the on-site environment on the measurement. The shielding cavity 8 is directly bonded to the pipe wall to solve the problem of being unable to perform measurement due to the small space size, and realizes effective noise testing in high temperature and high pressure environments.

[0052] As shown in FIG. 1 and FIG. 2 , a face screen 5 is provided in the shielding cavity 8 , and the multi-layer sound absorbing material 10 is fixed to the inner bottom side 82 of the shielding cavity 8 .

[0053] The shielding cavity 8 is constructed of metal plate, with a multilayer sound-absorbing material 10 applied to its inner bottom 82. The multilayer sound-absorbing material 10 comprises multiple layers of varying thicknesses. In one embodiment, the multilayer sound-absorbing material 10 comprises a first sound-absorbing material 1, a second sound-absorbing material 2, a third sound-absorbing material 3, and a fourth sound-absorbing material 4, arranged in that order. The outer side of the fourth sound-absorbing material 4 is secured to one end of the bottom 82 of the shielding cavity 8 via a protective mesh 5.

[0054] The multilayer sound-absorbing material 10 utilizes multiple layers of sound-absorbing structures and materials of varying types or thicknesses. Impedance matching between the different sound-absorbing structures and materials minimizes the effects of sound wave reflection and ensures the accuracy of microphone test results. The sound-absorbing structure of the multilayer sound-absorbing material 10 can include a resistive porous sound-absorbing structure, a resonance-resistant sound-absorbing structure, or a resistive-resistant composite sound-absorbing structure. The resistive porous sound-absorbing structure can be a multilayer structure composed of fiber materials and foam sponge materials, while the resonance-resistant sound-absorbing structure can be a multilayer perforated structure. The sound absorption performance of the sound-absorbing structure must be no less than 0.9 within the test frequency range.

[0055] The bulk density of each layer of resistive porous sound-absorbing structure is different, and the parameters of each layer of resonant resistance sound-absorbing structure are different, so as to achieve better sound insulation effect.

[0056] To ensure a better fit with the steam pipe 9, a flexible fitting mechanism 7 is installed at the opening 81 of the shielding cavity 8. Sealing rubber or sponge is adhered to the inner surface of the flexible fitting mechanism 7 to ensure isolation from other noise. The sound insulation of the shielding cavity 8 is no less than 30dB(A). During measurement, the opening 81 of the shielding cavity 8 is in close contact with the outer wall of the nuclear power plant steam pipe 9, and a microphone is inserted into the shielding cavity 8 through the side opening 6 for measurement. The sound insulation performance of the shielding cavity 8 is determined by the sound pressure level difference between the interfering sound source and the measured sound source in each frequency band. The determined sound insulation performance determines the material and thickness of the side walls of the shielding cavity 8.

[0057] In one embodiment, as shown in Figure 2, shielding cavity 8 is constructed from 3mm thick steel plate. Its bottom 82 is covered with multiple layers of sound-absorbing material 10, each 20cm thick. The first, second, third, and fourth sound-absorbing materials 1, 2, 3, and 4 are each 5cm thick and made of glass wool of varying bulk densities. A through-hole 6 is provided on the side of the tube, with a diameter of 7mm. To ensure a better fit with the nuclear power plant steam pipe 9, a flexible fitting mechanism 7 is provided at one end of the opening 81 of shielding cavity 8. This flexible fitting mechanism 7 extends 2cm outward from the opening 81, meaning the length of the fitting mechanism 7 in contact with the nuclear power plant steam pipe 9 is 2cm. A 2-3mm thick sealing rubber or 5mm thick sponge is applied to the side of the flexible fitting mechanism 7 facing the steam pipe 9 to ensure a tight fit.

[0058] The device 100 for measuring acoustically excited noise within a nuclear power plant steam pipe is applicable to nuclear power plant steam pipes 9 having different parameters. As shown in FIG2 , the nuclear power plant steam pipe 9 is a metal pipe without an outer insulation layer. The metal pipe may include one or more metal layers. The metal pipe in the embodiment of FIG2 includes one metal layer, and the pipe wall thickness is 44.2 mm.

[0059] FIG3 is a schematic diagram of another embodiment of a nuclear power plant steam pipe internal acoustic excitation noise measuring device 100 according to the present invention attached to the outer wall of a nuclear power plant steam pipe 9 .

[0060] As shown in Figure 3, in another embodiment, a nuclear power plant steam pipe 9 can be provided with an insulation layer 91, which is a high-temperature calcium silicate layer. The nuclear power plant steam pipe 9 includes a metal layer 92 and an insulation layer 91. The main parameters are: the pipe wall thickness of the metal layer 92 is 44.2 mm, and the thickness of the high-temperature calcium silicate layer of the insulation layer 91 is 130 mm.

[0061] FIG4 is a flow chart of a method for measuring acoustically excited noise in a steam pipeline of a nuclear power plant according to a specific embodiment of the present invention.

[0062] As shown in FIG4 , the method for measuring acoustically excited noise in a nuclear power plant steam pipeline of this embodiment uses the above-mentioned apparatus 100 for measuring acoustically excited noise in a nuclear power plant steam pipeline to perform measurement. The measurement method includes the following steps:

[0063] In step S1 , the flexible laminating mechanism 7 is attached to the outer wall of the steam pipe 9 of the nuclear power plant, and the multi-layer sound absorbing material 10 isolates the noise in the external environment of the shielding cavity 8 .

[0064] Step S2: Place the microphone in the shielding cavity 8 through the through hole 6 to measure the noise outside the steam pipe 9 of the nuclear power plant. pout .

[0065] Step S3: Calculate the pipeline transmission loss TL.

[0066] A pipeline sound insulation model is established based on the transfer matrix method. The model includes impedance models of various material layers of the nuclear power plant steam pipeline 9 and calculates the pipeline transmission loss TL. The pipeline sound insulation model is established according to the pipeline wall thickness of the nuclear power plant steam pipeline 9.

[0067] Step S4: according to the pipeline transmission loss TL and the noise pressure level L outside the pipeline pout The sum of the noise pressure level in the pipe is L pin =TL+L pout .

[0068] In one embodiment, in step S3, calculating the pipeline transmission loss includes the following steps:

[0069] Step S31 : establishing a pipe sound insulation model based on the transfer matrix method. The pipe sound insulation model includes impedance models of various layers of material of the steam pipe 9 , including a steam pipe metal layer 92 and an insulation layer 91 .

[0070] Step S32, calculate the acoustic impedance Z of each layer of material in the steam pipe 9 i .

[0071] Step S33: Calculate the transmission loss TL of each layer of material in the steam pipe 9 according to the acoustic impedance.

[0072] In step S32, the acoustic impedance Z of each layer of material in the steam pipe 9 is calculated. i The two calculation methods include step S321 and step S322, which respectively calculate the acoustic impedance Z of each layer of material. i Then, the surface acoustic impedance Z of each layer of the steam pipe material is calculated in step S323. si .

[0073] In step S321, the acoustic impedance Z of each metal layer can be calculated. i .

[0074] Acoustic impedance Z of each metal layer i The calculation formula is as follows:

[0075] Where j is the imaginary unit, f is the noise frequency, K i is the stiffness coefficient of the i-th layer material, f coi is the matching frequency of the i-th layer material, f ringi is the ring frequency of the i-th layer material, E i is the Young's modulus of the i-th layer material, v i is the Poisson's ratio of the i-th layer material, h i is the thickness of the i-th layer of material, η i is the damping coefficient of the i-th layer material, m i is the surface density of the i-th layer material, R i is the radius of curvature of the i-th layer of material, and c0 is the speed of sound in air.

[0076] In step S322, the acoustic impedance Z of each insulation layer 91 can be calculated. n .

[0077] The acoustic impedance Z of each insulation layer 91 n The calculation formula is as follows:

[0078] Among them, k n is the wave number of the sound wave in the nth layer of material, ρ0 is the air density, σ n is the flow resistivity of the nth layer material, t n is the thickness of the nth layer of material.

[0079] For the nuclear power plant steam pipe 9 including only a metal layer in the embodiment of FIG. 2 , the acoustic impedance Z of each layer of the steam pipe 9 is calculated. i When calculating, the method of step S321 can be used; for the nuclear power plant steam pipe 9 including both a metal layer 92 and an insulation layer 91 in Figure 3, when calculating, the acoustic impedance Z of each metal layer 92 can be calculated by step S321. i Then calculate the acoustic impedance Z of the insulation layer 91 by the method of step S322 n .

[0080] In step S323, the surface acoustic impedance Z of each layer of the steam pipe material is calculated by the transfer matrix method. si .

[0081] If the acoustic impedance of the i-th layer material is Z i , the acoustic impedance of the i-1th layer material is Z i-1 , then the surface acoustic impedance of the i-th layer material is calculated as follows:

[0082] The surface acoustic impedance Z of the material is calculated up to the Nth layer (the last layer).

[0083] In step S33, the transmission loss TL of the multi-layer material (including the steam pipe and the insulation layer) is calculated using the following formula:

[0084] Through the above calculation method, the pipeline transmission loss TL can be obtained, and thus the noise pressure level L in the pipe can be obtained. pin =TL+L pout .

[0085] Figure 5 is a noise spectrum curve measured in the shielding cavity 8 of the embodiment shown in Figure 2. Figure 6 is a spectrum curve of the calculated pipeline transmission loss TL of the embodiment shown in Figure 2. Figure 7 is a comparison between the measured and calculated sound pressure levels in the pipe of the embodiment shown in Figure 2.

[0086] In one embodiment, for a nuclear power plant steam pipe 9 (including only a metal layer but not an insulation layer) as shown in FIG2 , when the air flow velocity of the nuclear power plant steam pipe 9 is 55 m / s, in order to calculate the noise inside the nuclear power plant steam pipe 9, first, the noise pressure level L outside the pipe is measured by the noise measuring device 100. pout , and its noise spectrum is shown in Figure 5; secondly, by establishing the sound insulation model of the nuclear power plant steam pipe 9 based on the impedance method and transfer matrix method, the pipeline transmission loss TL is calculated, and its spectrum is shown in Figure 6; finally, according to the formula L pin =TL+L pout Get the noise pressure level L inside the steam pipe 9 pin , as shown in Figure 7.

[0087] FIG7 shows the noise pressure level L in the pipe calculated by the method for measuring the noise of the nuclear power plant steam pipe according to the present invention. pin , and the noise pressure level L in the pipe measured in the steam pipe 9 of the nuclear power plant under experimental conditions pt In order to measure the noise pressure level L in the steam pipe 9 of the nuclear power plant pt In the laboratory, a simulation experiment was conducted on the noise inside the nuclear power plant steam pipe 9. For the nuclear power plant steam pipe 9 of the embodiment of FIG2 , the outer wall of the pipe was not provided with the insulation layer 91, and the air flow velocity inside the nuclear power plant steam pipe 9 was set to 55 m / s. The noise sound pressure level L in the pipe was obtained by actual measurement inside the nuclear power plant steam pipe 9. pt .

[0088] As can be seen from the comparison in FIG7 , the in-pipe noise results of the nuclear power plant steam pipe 9 of the embodiment shown in FIG2 obtained by the noise measurement device 100 and the in-pipe noise calculation method are very similar to the actual measured results under experimental conditions, indicating that the noise measurement device 100 and the calculation method of the present invention are effective and feasible.

[0089] Figure 8 is the noise spectrum curve measured in the shielding cavity of the embodiment shown in Figure 3. Figure 9 is the noise spectrum curve after calculating the pipeline transmission loss TL of the embodiment shown in Figure 3. Figure 10 is a comparison between the measured and calculated sound pressure levels in the pipe of the embodiment shown in Figure 3.

[0090] For the nuclear power plant steam pipe 9 (including both the metal layer 92 and the insulation layer 91) shown in FIG3, when the unit is running at power, in order to calculate the noise inside the nuclear power plant steam pipe 9 of the unit, first, the noise pressure level L outside the pipe is measured by the noise measuring device 100. pout , and its noise spectrum is shown in Figure 8; secondly, the sound insulation model of the nuclear power plant steam pipe 9 is established by the transfer matrix method, and the pipeline transfer loss TL is calculated, and its spectrum is shown in Figure 9; finally, according to the formula L pin =TL+L pout The noise sound pressure level inside the steam pipe 9 is obtained, and the measured and calculated noise spectra are shown in FIG10 .

[0091] FIG10 shows the noise pressure level L in the pipe of the embodiment shown in FIG3 calculated by the method for measuring the noise of the nuclear power plant steam pipe by acoustic excitation according to the present invention. pin , and the noise pressure level L in the pipe measured in the steam pipe 9 of the nuclear power plant under experimental conditions pt As can be seen from the comparison in FIG10 , the in-pipe noise results of the nuclear power plant steam pipe 10 obtained by the device and the in-pipe noise calculation method are very close to the measured results, indicating that the in-pipe high-intensity acoustic excitation measurement device and calculation method are effective and feasible.

[0092] The present invention arranges a multi-layer sound-absorbing material 10 at one end near the bottom side 82 in the shielding cavity 8, and arranges a flexible fitting mechanism 7 at the opening 81 of the shielding cavity 8; during measurement, the flexible fitting mechanism 7 is fitted on the outer wall of the steam pipe 9 of the nuclear power plant to isolate the noise of the external environment of the shielding cavity 8, and the microphone is placed in the shielding cavity 8 through the through hole 6 for measurement, and then the pipe transmission loss is calculated to obtain the sound pressure level of the pipe noise in the steam pipe of the nuclear power plant, thereby realizing non-destructive indirect measurement of the pipe noise outside the steam pipe 9 of the nuclear power plant, and having the advantages of anti-interference and easy installation. The noise isolation of the shielding cavity 8 and the multi-layer sound-absorbing material 10 and the close fitting of the flexible fitting mechanism 7 on the pipe wall eliminate the influence of the on-site environment on the measurement. The shielding cavity 8 is directly fitted on the pipe wall to solve the problem of being unable to perform measurement due to the small space size, thereby realizing effective noise testing in a high temperature and high pressure environment.

[0093] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A device for measuring acoustic excitation noise in a steam pipeline of a nuclear power plant, characterized in that: include: microphone; A shielding cavity, a side wall of which is provided with a through hole for the microphone to enter the shielding cavity, and one end of the shielding cavity is provided with an opening; A multi-layer sound absorbing material is arranged on the bottom side of the shielding cavity, wherein the bottom side is an end away from the opening of the shielding cavity; A flexible fitting mechanism, which is arranged at the opening of the shielding cavity; in, The flexible fitting mechanism can be fitted on the outer wall of a steam pipe in a nuclear power plant, the multi-layer sound-absorbing material isolates the noise of the external environment of the shielding cavity, and the microphone is placed in the shielding cavity through the through hole for measurement.

2. The device for measuring acoustic excitation noise in a steam pipeline of a nuclear power plant according to claim 1, characterized in that: A protective net is arranged in the shielding cavity, and the multi-layer sound absorbing material is fixed on the bottom side inside the shielding cavity.

3. The device for measuring acoustic excitation noise in a steam pipeline of a nuclear power plant according to claim 1, characterized in that: The thickness of each layer of the multi-layer sound absorbing material is different.

4. The device for measuring acoustic excitation noise in a steam pipeline of a nuclear power plant according to claim 1, characterized in that: The multi-layer sound absorbing material is one or more of a resistive porous sound absorbing structure, a resonant resistant sound absorbing structure and a resistive resistant composite sound absorbing structure.

5. The device for measuring acoustic excitation noise in a steam pipeline of a nuclear power plant according to claim 4, characterized in that: The bulk density of each layer of the resistive porous sound absorbing structure is different, and the parameters of each layer of the resonance resistance sound absorbing structure are different.

6. The device for measuring acoustic excitation noise in a steam pipeline of a nuclear power plant according to claim 1, characterized in that: The inner side of the flexible fitting mechanism is provided with rubber or sponge.

7. A method for measuring acoustically excited noise in a steam pipeline of a nuclear power plant, using the device for measuring acoustically excited noise in a steam pipeline of a nuclear power plant as described in claims 1 to 6, characterized in that: The measuring method comprises the following steps: The flexible laminating mechanism is attached to the outer wall of the steam pipeline of the nuclear power plant, and the multi-layer sound absorbing material isolates the noise in the external environment of the shielding cavity; The microphone is placed in the shielding cavity through the through hole to perform measurement, thereby obtaining the sound pressure level of the external noise of the steam pipeline of the nuclear power plant.

8. The method for measuring acoustic excitation noise in a steam pipeline of a nuclear power plant according to claim 7, characterized in that: The following steps are also included: Calculating the pipeline transmission loss of the steam pipeline of the nuclear power plant; The sound pressure level of the noise inside the pipe is obtained according to the sum of the pipeline transmission loss and the sound pressure level of the noise outside the pipe.

9. The method for measuring acoustic excitation noise in a steam pipeline of a nuclear power plant according to claim 8, characterized in that: The calculating of the pipeline transmission loss of the steam pipeline of the nuclear power plant comprises: A pipeline sound insulation model is established based on the transfer matrix method. The pipeline sound insulation model includes the An impedance model of each layer of material of the steam pipeline, wherein each layer of material of the steam pipeline includes a metal layer and an insulation layer of the steam pipeline; Calculating the acoustic impedance of each layer of material of the steam pipeline; The transmission loss of each layer of material of the steam pipe is calculated based on the acoustic impedance.

10. The method for measuring acoustic excitation noise in a steam pipeline of a nuclear power plant according to claim 9, characterized in that: The calculating of the acoustic impedance of each layer of material of the steam pipeline comprises: Calculate the acoustic impedance of each metal layer; Calculate the acoustic impedance of each insulation layer; The surface acoustic impedance of each layer of the steam pipe material is calculated using the transfer matrix method.

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