Physics-based optimization method for cooling tower noise reduction

Abstract

To provide a cooling tower noise reduction optimization method based on a physical model, the method belonging to a technical field of a noise reduction design.SOLUTION: Using BIM technique, the present invention constructs a graphical model; provides a noise reduction design scheme in real time intuitively and three-dimensionally on the basis of physical simulation of the graphical model; can achieve improvement of a noise reduction structure easily and accurately by further constructing data simulation of a function model; and acquires a noise reduction structure design plan at an optimum construction cost by establishing a target optimization model of an economical cost. The present invention improves cooling tower noise reduction design efficiency effectively, and automatically balances a cooling tower noise reduction countermeasure effect with a construction execution cost, thereby enhancing reliability and economical efficiency of the noise reduction structure design.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to the technical field of noise reduction design, and in particular to a cooling tower noise reduction optimization method based on a physical model. [Background technology]

[0002] As people's demands for quality of life improve, the requirements for noise control in buildings are also becoming increasingly stringent. The noise of electromechanical systems is an important aspect that affects noise control in buildings. Outdoor cooling towers, one of the main noise sources of electromechanical systems, tend to cause acoustic pollution in the surrounding environment because the noise generated by their operation is dispersed into the air.

[0003] At present, the noise control capabilities of cooling tower manufacturers are weak, and many products have not been equipped with additional noise reduction measures. In actual operation, they do not meet China's secondary environmental protection standards, namely GB55016-2021 and GB3096-2008, i.e., they do not meet the requirement of night noise ≦45~50dB(A). Only a few low-tonnage ultra-low noise model cooling towers can meet the requirements of night noise standards in a few regions.

[0004] The conventional cooling tower noise reduction design method uses two-dimensional layout to comprehensively consider the topographical map provided by the design agency, the detailed layout drawing of the cooling tower and piping, the design explanation, and the detailed equipment drawing provided by the cooling tower manufacturer. In the layout process, empirical formulas are used to perform theoretical noise reduction calculations and structural design. This method is not intuitive, prone to leaks, takes time and effort, and cannot be adjusted in real time, so it cannot achieve the goal of automatically optimizing the noise reduction structure according to needs.

[0005] In recent years, BIM technology and target optimization algorithms have been upgraded and gradually applied to the field of noise management. BIM technology can determine the need for noise reduction measures for the noise impact area through physical simulation based on graphical models, while target algorithms can improve the noise reduction structure and optimize construction costs by building data simulations of functional models. Combining the two, a cooling tower noise reduction method can be formed to solve existing problems. Summary of the Invention [Problem to be solved by the invention]

[0006] Considering the shortcomings of existing technologies, the present invention provides a cooling tower noise reduction optimization method based on a physical model, uses BIM technology to build a graphical model, and based on the physical simulation of the graphical model, simulates additional noise reduction measures for the influence range of the cooling tower noise source and propagation path, and constructs a data simulation of a function model to improve the noise reduction structural design, and performs economic cost target optimization to obtain the most economical cooling tower noise reduction structural design scheme with noise reduction equipment. [Means for solving the problem]

[0007] The present invention has achieved the above technical object by the following technical means. 1. A physical model-based cooling tower noise reduction optimization method, comprising the steps of: Step 1: Determine the noise reduction targets within the functional area and noise impact zone of the acoustic environment where the cooling tower is installed. Step 2: Build a high-precision model of the cooling tower itself, a high-precision model of the system piping, and a high-precision model of the associated components. Step 3: Based on the model constructed in Step 2, continue to construct an engineering model including the terrain, buildings, support structures, roadways, shafts, and passageways of the cooling tower placement area to form a constrained model. Step 4: Based on the constraint model, continue to build an engineering model including the cooling tower equipment, system piping, pipe components, valves, shock absorbers, and distribution boxes to form a functional model. Step 5, based on the functional model, a model of the surrounding building is constructed, and the location of the noise reduction target in the sensitive area of ​​the building is marked to construct the target model. Step 6: Based on the target model, the cooling tower equipment is laid out in a modular format, and inspection doors are installed at the same time. Step 7: Calculate the superimposed noise levels of all cooling tower module groups after the modular combination process in Step 6. Step 8: Calculate the amount of noise to be treated that is transmitted to each sensitive point by the superimposed noise from the intake side, shroud side and exhaust side of the cooling tower. Step 9: Based on the amount of noise to be processed, a sound-absorbing structure is set for each cooling tower of the target model after the modularized combination processing in Step 6. Step 10: To optimize the noise structure designed in Step 9, a function model is constructed and data simulation is performed. Step 11: Construct a cooling tower noise reduction equipment economic cost optimization model aimed at minimizing the economic cost of constructing cooling tower noise reduction equipment, and solve the model to obtain a cooling tower noise reduction structural design scheme that optimizes the economic efficiency of the noise reduction equipment.

[0008] Furthermore, in step 9 above, the sound deadening structure is set as follows: On the inlet side of the cooling tower, a sound-absorbing louver with a built-in sound-absorbing insert is installed, the length of the sound-absorbing louver is long enough to cover the length of the cooling tower inlet, and the height is high enough to cover the height of the cooling tower inlet, so that the total area meets the cooling tower's intake requirements, and the remaining area is used as a sound-insulating barrier. On the side of the cooling tower's side panel, a fully sealed sound-insulating barrier is used, which covers the cooling tower placement area, and its top is flush with the cooling tower's exhaust outlet. An openable inspection door is provided in advance, and an inspection ladder is installed according to the restriction model. On the exhaust side of the cooling tower, a silencer with a built-in sound-insulating insert is installed, and a gentle air flow area is ensured between the silencer and the cooling tower's exhaust outlet, and a flow guide plate is installed.

[0009] Furthermore, the specific process of the above step 10 is as follows: Step 10.1: Using equations (1) to (4), the noise level to be treated by the sound-reducing louver, L A T , the noise level to be treated by the silencer L E T , the intake coefficient of the sound-absorbing louver I A , exhaust coefficient I E are calculated respectively.

[0010]

number

[0011]

number

[0012]

number

[0013]

number

[0014] In equation (1), a0 is the normal incidence sound absorption coefficient of the sound absorbing material, Φ(a0) is the sound attenuation coefficient related to the normal incidence sound absorption coefficient of the sound absorbing material, and L A is the effective sound-absorbing length of the sound-absorbing insert of the sound-absorbing louver, and L d is the spacing between the sound-absorbing inserts of the sound-absorbing louver, and in equation (2), L E is the effective silencing length of the silencer insert, and M d is the spacing between the silencer inserts, and in equation (3), L1 is the length of the silencer louver, and L i is the number of sound-absorbing inserts in the sound-absorbing louver, A1 is the length of the cooling tower inlet, and A d is the width of the cooling tower inlet, and A iis the number of inlets of each cooling tower, W is the number of cooling towers, K is the cooling tower intake coefficient, and in equation (4), M1 is the length of the silencer, and M i is the number of silencer silencer inserts, and E d is the diameter of the cooling tower outlet, and E i is the number of exhaust ports of each cooling tower, and the average inlet air velocity V A and average exhaust air velocity V E Calculate each.

[0015]

number

[0016]

number

[0017] In equations (5) and (6), Q is the air volume of one cooling tower, and the pressure loss of the silencer louver, H, is calculated using equations (7) and (8). A and the pressure loss of the silencer H E Calculate each.

[0018]

number

[0019]

number

[0020] In equations (7) and (8), ξ1 and ξ2 are both local resistance coefficients, ρ is the air density, and equations (9) and (10) are used to calculate the regenerative noise L that needs to be considered at the cooling tower outlet. W , exhaust air flow area S E Calculate.

[0021]

number

[0022]

number

[0023] In equation (9), a is the regeneration coefficient.

[0024] Step 10.2, using equations (1), (3), (5) and (7), establish the inter-control relationship between the effective sound-absorbing length and spacing of the sound-absorbing inserts of the sound-absorbing louvers that meet the noise target limit values ​​shown below.

[0025]

number

[0026] Equations (2), (4), (6), (8), (9), and (10) are utilized to establish the inter-control relationship between the effective silencing length and spacing of the silencing inserts of the silencer to meet the noise target limits shown below.

[0027]

number

[0028] Step 10.3: The mutual control relationship is taken as a mathematical model, and L is calculated according to the optimization needs, assuming that the noise reduction target limit value is met. A and L d and L E and M d The value trends are balanced and adjusted to achieve the optimum noise reduction structure.

[0029] Furthermore, the specific process of the above step 11 is as follows: The following equations (11), (12), and (13) are used to calculate the economic cost of constructing the silencer louvers on the intake side, the economic cost of constructing the silencer on the exhaust side, and the economic cost of constructing the cooling tower noise reduction equipment, respectively.

[0030]

number

[0031]

number

[0032]

number

[0033] In equation (11), L A Pi is the noise level of the ith sound-reducing louver, and in equation (12), L E P is the superimposed noise of the silencer, and L E Pi is the noise level of the ith silencer, N is the number of sound sources included in each group of cooling tower modules, D is the number of levels of noise energy increase when multiple cooling tower module groups operate simultaneously, and in equation (13), M is the economic cost of construction, X is the economic cost coefficient of construction, and d A is the thickness of the sound-absorbing insert of the sound-absorbing louver, and d E is the thickness of the sound-deadening insert of the sound-deadening louver, Therefore, the economic cost optimization model for the cooling tower noise reduction equipment, which was developed with the aim of minimizing the economic costs of constructing the cooling tower noise reduction equipment, is shown in the following equation (14).

[0034]

number

[0035] The decision variables in the economic cost optimization model for cooling tower noise reduction equipment include the effective silencing length of the silencing louvers, the spacing between the silencing inserts of the silencing louvers, the effective silencing length of the silencer, and the spacing between the silencing inserts of the silencer.

[0036] Next, Python (registered trademark)Based on the Gurobi optimization solver under the platform, the economic cost optimization model of the cooling tower noise reduction equipment is solved, and the cooling tower noise reduction structural design scheme with the most economically optimal noise reduction equipment is output.

[0037] Furthermore, the superimposed noise level L P‘ is calculated using the following formula:

[0038]

number

[0039] In the formula, N is the number of sound sources included in each group of cooling tower modules, D is the number of noise energy levels that increase when multiple cooling tower module groups operate simultaneously, and L Pi is the i-th noise level.

[0040] Furthermore, the amount of noise to be processed in step 8 is calculated by the following formula:

[0041]

number

[0042]

number

[0043] In the formula, L P‘ are the superimposed noise levels of the cooling tower module group, and L eq is the specified noise limit value, ΔL is the noise attenuation, r1 is the distance from sound receiving point 1 to the sound source, and r2 is the distance from sound receiving point 2 to the sound source.

[0044] Furthermore, the sound insulation barrier uses 100mm-thick modular sound screen panels with a sound insulation capacity of 24dB or more, the perforated panels are made of 0.8mm perforated aluminum plates, the sound-absorbing material is made of 100mm-thick anti-corrosion, hydrophobic, and non-flammable sound-absorbing cotton with a high sound absorption coefficient, a 2mm-thick damping layer is used between the sound screen panel and the outer layer of galvanized steel plate, the inner frame of the sound-absorbing louver uses a hot-dip galvanized structure, and triangular flow guide plates are used on both ends of the silencer. [Effects of the Invention]

[0045] The present invention has the following beneficial effects: Compared with existing cooling tower noise reduction methods, the cooling tower noise reduction optimization method based on a physical model of the present invention establishes a physical simulation of a graphic model to provide an intuitive and three-dimensional real-time noise reduction design scheme, constructs a data simulation of a function model, and conveniently and accurately realizes the improvement of the noise reduction structure. It also performs economic cost target optimization and automatically provides an optimal structural design scheme according to construction costs. The present invention effectively improves the efficiency of cooling tower noise reduction design, automatically balances the effectiveness of cooling tower noise reduction measures with construction implementation costs, and improves the reliability and economy of noise reduction structural design. [Brief explanation of the drawings]

[0046] [Figure 1] FIG. 1 is a three-dimensional schematic diagram of a cooling tower model. [Figure 2] FIG. 1 is a schematic plan view of a restriction model. [Figure 3] FIG. 2 is a three-dimensional schematic diagram of a functional model. [Figure 4] FIG. 2 is a three-dimensional schematic diagram of a target model. [Figure 5] FIG. 2 is a three-dimensional schematic diagram of the arrangement of the sound absorbing structure. DETAILED DESCRIPTION OF THE INVENTION

[0047] The present invention will be further described below with reference to the drawings and specific examples, but the protection scope of the present invention is not limited thereto.

[0048] The cooling tower noise reduction optimization method based on the physical model of the present invention includes the following processes. Step 1: Determine the functional area of ​​the acoustic environment where the cooling tower 1 is installed and the noise reduction target within the noise influence range in accordance with the provisions of GB-55016-2021 "General Specifications for the Building Environment (General Standards for the Building Environment)" and GB-3096-2008 "Acoustic Environment Quality Standard (Acoustic Environment Quality Standard)". In this embodiment, the two types of acoustic environment functional areas where the cooling tower 1 is located in Table 1 below (i.e., daytime (06:00~22:00) ≦ 60dB(A), nighttime (22:00~6:00 the next day) ≦ 50dB(A)) are taken as examples to explain the solution.

[0049] [Table 1]

[0050] When there are no other noise sources, select points in each sensitive area 1 meter from the entrances and windows of the building and measure the steady noise 1-minute equivalent sound level L using the noise-sensitive building inspection method. eq must be tested and must not exceed the specified limits.

[0051] Step 2: Based on the matching sample from the cooling tower equipment manufacturer, we extracted the required parameter information such as size, specifications, and model. Based on BIM technology, we used the sample file of the metric traditional family based on the surface in Revit software to build a high-precision model of the cooling tower body shown in Figure 1.

[0052] Step 3: Extract the necessary parameter information such as material, specification, series, pipe outer diameter, pipe inner diameter, etc. from GBT3091-2015 "Welded steel pipe for low-pressure fluid transportation." Based on the high-precision model of the cooling tower body established in Step 2, a high-precision model of the system piping was established in Revit software using BIM technology and a sample file of a line-based metric conventional family.

[0053] Step 4: Extract the required specifications, model, series, dimensions, material and other parameter information from the manufacturer's atlas of GBT12459-2005 "Steel Butt-welded Seamless Pipe Parts", the valve manufacturer's sample "Guanlong Valve", and accessories such as distribution boxes. Based on the high-precision model of the system piping established in Step 3, using BIM technology in Revit software, establish pipe fitting models such as elbows, reducers, tees, etc. using sample files of metric traditional families. At the same time, establish high-precision models of valves such as butterfly valves, electric butterfly valves, water distribution devices, and accessories such as shock absorbers, distribution boxes, and ladders.

[0054] Step 5: Based on the design drawings of the area surrounding the cooling tower 1 placement area and the recorded materials surveyed and drawn up for the construction site, and using the sample file of the new project in Revit software based on BIM technology, a one-to-one engineering model was established for the cooling tower 1 placement area, including the terrain, building 5, supporting structure 6, roadway 2, shaft 4, passageway 3, etc., as well as facilities, boundaries, and signs, i.e., the construction of the constraint model shown in Figure 2 was completed.

[0055] Step 6: Combining the cooling tower layout design drawing and engineering detailed design technology, based on BIM technology, and using the coordinate and axis grid as the positioning basis, a one-to-one engineering model was established based on the limited model constructed in Step 5, including the cooling tower equipment, system piping 7, pipe components 8, valves 9, shock absorbers, distribution boxes 10 and other accessories, i.e., the construction of the functional model shown in Figure 3 was completed.

[0056] Step 7: Based on the design documents, urban construction plan drawings, and the surveyed and drafted records of the construction site, and using BIM technology, in Revit software, coordinates, axis grids, and elevations were used as the layout basis. Based on the functional model constructed in Step 6, a model of 11 surrounding buildings was established, and the main impact facilities on the noise propagation range were identified. Next, noise reduction target locations for sensitive areas such as building entrances and windows were marked, thereby completing the construction of the target model shown in Figure 4.

[0057] Step 8: Adopt the equipment combination mode of three units in one group and two units in one group, and arrange the number of groups to meet the demand according to the refrigeration ton design. Based on the target model constructed in Step 7, lay out the cooling tower equipment in a modular form. At the same time, install an inspection door that penetrates the equipment, taking into consideration the realization of the function of cooling tower 1 and the internal inspection requirements of the equipment.

[0058] Step 9: After processing in step 8, the noise generated on the intake side, side panel side and exhaust side of each cooling tower 1 in the target model is superimposed and analyzed to determine the superimposed noise of the cooling tower module group. When multiple cooling tower module groups are operating at the same time, the noise energy will increase by level D, and the superimposed noise of all cooling tower module groups after the modularized combination will be as follows:

[0059]

number

[0060] L Pi is the i-th noise level.

[0061] Step 10: Use the following formula to calculate the amount of noise to be processed that is transmitted to each sensitive point by the superimposed noise on the intake side, shroud side, and exhaust side of the cooling tower 1 (i.e., the part of the noise that is transmitted to the sensitive point and exceeds the specified limit value even after attenuation is complete).

[0062]

number

[0063]

number

[0064] In the formula, L T is the noise level to be processed, and L eqis the specified noise limit value, ΔL is the noise attenuation, r1 is the distance from sound receiving point 1 to the sound source, and r2 is the distance from sound receiving point 2 to the sound source.

[0065] The sensitive point refers to the most undesirable impact point that would cause serious inconvenience to nearby apartments, hotels, houses, commercial buildings, office buildings, etc. if the cooling tower 1 were not subjected to noise reduction treatment.

[0066] Step 11: Based on the noise level data to be processed calculated in step 10, install sound-absorbing louvers with built-in sound-absorbing inserts on the intake side (usually on both opposing sides) of each cooling tower 1 in the target model processed in step 8, the length of the sound-absorbing louvers is long enough to cover the length of the cooling tower 1 intake, the height is high enough to cover the height of the cooling tower 1 intake, the total area meets the intake requirements of the cooling tower 1, and the remaining part is a sound-insulating barrier; A completely sealed sound barrier is used on the side panel side (usually on both opposing sides) of the cooling tower 1, the sound barrier covers the cooling tower 1 placement area, the top is flush with the cooling tower 1 exhaust port, an openable inspection door is secured in advance, and an inspection ladder is installed according to the restriction model to facilitate subsequent maintenance; A silencer with a built-in silencer insert is installed on the exhaust side of the cooling tower 1, ensuring a gentle air flow area between the silencer and the exhaust port of the cooling tower 1. A guide plate is installed to ensure that the exhaust airflow does not overflow to the intake side of the cooling tower 1 but flows directly to the silencer. The materials for the sound insulation barrier (composed of galvanized steel plate, sound absorbing material, and perforated plate), sound absorbing louver (composed of galvanized steel plate, sound absorbing material, and perforated plate), sound silencer (composed of perforated plate, sound absorbing material, and perforated plate), cushion, structural frame, beam, etc. can be selected according to the actual situation of the project. The materials selected in this embodiment are: The sound insulation barrier is made of 100mm-thick modular sound screen panels with a sound insulation rate of over 24dB(A), effectively shortening the production and construction cycle and facilitating maintenance. The perforated panels are made of 0.8mm perforated aluminum plates with a perforation rate that meets design requirements. The sound-absorbing material is made of 100mm-thick, anti-corrosive, hydrophobic, and non-flammable sound-absorbing cotton with a high sound absorption coefficient. A 2mm-thick damping layer is used between the sound screen panels and the outer layer of galvanized steel to reduce low-frequency noise. The steel structural frame's vertical columns are made of 125x125mm H-shaped welded steel main frames, and the beams are made of 100x50x3mm welded steel subframes. The inner frames of the sound-absorbing louvers are made of hot-dip galvanized material, and triangular air guide plates are used on both ends of the silencer to reduce air resistance.

[0067] Step 12: To optimize the sound deadening structure designed in Step 11 and confirm the noise reduction effect, a function model was constructed and data simulation was performed.

[0068] Step 12.1: Using equations (1) to (4), the noise level to be treated by the silencer louver, L A T , the noise level to be treated by the silencer L E T , the intake coefficient of the sound-absorbing louver I A , exhaust coefficient I E were calculated respectively.

[0069]

number

[0070]

number

[0071]

number

[0072]

number

[0073] In equation (1), a0 is the normal incidence sound absorption coefficient of the sound absorbing material, Φ(a0) is the sound attenuation coefficient related to the normal incidence sound absorption coefficient of the sound absorbing material, and L A is the effective sound-absorbing length of the sound-absorbing insert of the sound-absorbing louver, and L d is the spacing between the sound-absorbing inserts of the sound-absorbing louver, and in equation (2), L E is the effective silencing length of the silencer insert, and M d is the spacing between the silencer inserts, and in equation (3), L1 is the length of the silencer louver, and L i is the number of sound-absorbing inserts in the sound-absorbing louver, A1 is the length of the inlet of cooling tower 1, and A d is the width of the inlet of cooling tower 1, and A i is the number of inlets of each cooling tower 1, W is the number of cooling towers 1, K is the intake coefficient of cooling tower 1, and in equation (4), M1 is the length of the silencer, and M i is the number of silencer silencer inserts, and E d is the diameter of the cooling tower 1 exhaust port, and E i is the number of exhaust ports for each cooling tower1, and according to the equipment manufacturer's data, I A , I E ≧1.5 indicates good heat dissipation, and the lower limit of the values ​​that equations (3) and (4) take is both 1.5. Using the following equations (5) and (6), the average inlet air velocity V A and average exhaust air velocity V E were calculated respectively.

[0074]

number

[0075]

number

[0076] In equations (5) and (6), Q is the air volume of one cooling tower. According to the equipment manufacturer's information, an air duct flow velocity of ≦8 m / s indicates good air circulation, so the upper limit of the values ​​that equations (5) and (6) can take is 8. Using the following equations (7) and (8), the pressure loss of the silencer louver, H A and the pressure loss of the silencer H E were calculated respectively.

[0077]

number

[0078]

number

[0079] In equations (7) and (8), ξ1 and ξ2 are both local resistance coefficients, and ρ is the air density. According to the equipment manufacturer's information, a pressure loss of ≦100 Pa means that the pressure loss is acceptable. Therefore, the upper limit of the values ​​that equations (7) and (8) can take is 100. Using the following equations (9) and (10), the regenerative noise L that needs to be considered at the cooling tower exhaust outlet can be calculated. W , exhaust air flow area S E was calculated.

[0080]

number

[0081]

number

[0082] In equation (9), a is the regeneration coefficient, and its value was obtained by referring to the Practical Heating and Air Conditioning Design Manual (Practical Heat Supply Air Conditioning Design Manual [M], published by China Construction Industry Press, 2008).

[0083] Step 12.2: Using equations (1), (3), (5), and (7), determine the relationship between the effective sound-absorbing length and spacing (i.e., L) of the sound-absorbing inserts of the sound-absorbing louvers that meet the noise target limits shown below. A and L d A mutual control relationship between them was established.

[0084]

number

[0085] Using equations (2), (4), (6), (8), (9), and (10), the relationship between the effective silencing length and spacing (i.e., L E and M d A mutual control relationship between them was established.

[0086]

number

[0087] Step 12.3: Using the two mutual control relationships obtained in Step 12.2 as a mathematical model, L is optimized according to the optimization needs, assuming that the noise reduction target restrictions are met. A and L d and L E and M d By balancing and adjusting the value trends of , it is possible to achieve optimization of the noise reduction structure (i.e., the sound deadening structure shown in FIG. 5).

[0088] For example, to ensure an economical design of sound-absorbing structures, L A Make L smaller d Increase the size and L E Make M smaller d On the other hand, to ensure the effectiveness of the sound absorption structure design, L A Increase the size and L d Make L smaller E Increase M d Reduces.

[0089] Step 13: A cooling tower noise reduction equipment economic cost optimization model was constructed with the aim of minimizing the economic cost of the construction of cooling tower 1 noise reduction equipment, and the model was solved to obtain a cooling tower 1 noise reduction structure design scheme that optimized the economy of the noise reduction equipment.

[0090] The economic cost of constructing cooling tower 1 noise reduction equipment is directly related to the effective silencing length and noise reduction area, and the economic cost of constructing the silencing louvers on the intake side, the economic cost of constructing the silencer on the exhaust side, and the economic cost of constructing cooling tower 1 noise reduction equipment were calculated using the following equations (11), (12), and (13), respectively.

[0091]

number

[0092]

number

[0093]

number

[0094] In equation (11), L A Pi is the noise level of the ith sound-reducing louver, and in equation (12), L E P is the superimposed noise of the silencer, and L E Pi is the noise level of the ith silencer, N is the number of sound sources included in each group of cooling tower modules, D is the number of levels of noise energy increase when multiple cooling tower module groups operate simultaneously, and in equation (13), M is the economic cost of construction, X is the economic cost coefficient of construction, and d A is the thickness of the sound-absorbing insert of the sound-absorbing louver, and d E is the thickness of the sound-deadening insert of the sound-deadening louver, Therefore, the economic cost optimization model of the cooling tower noise reduction equipment, which was constructed with the aim of minimizing the economic cost of constructing the cooling tower noise reduction equipment, is shown in the following equation (14).

[0095]

number

[0096] The decision variables in the economic cost optimization model for cooling tower noise reduction equipment include the effective silencing length of the silencing louvers, the spacing between the silencing inserts of the silencing louvers, the effective silencing length of the silencer, and the spacing between the silencing inserts of the silencer.

[0097] Next, Python (registered trademark) Based on the Gurobi optimization solver under the platform, the economic cost optimization model of the cooling tower noise reduction equipment is solved, and the cooling tower noise reduction structural design scheme with the most economical and optimal noise reduction equipment is output, and the function model file and optimization scheme code program file are saved for later use.

[0098] The noise-sensitive building inspection method is a conventional method used in the art, and therefore a detailed description thereof will be omitted in this example. The examples described in this specification are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Any obvious improvements, substitutions, or modifications that can be made by those skilled in the art without departing from the essence of the present invention are within the protection scope of the present invention. [Explanation of symbols]

[0099] 1 cooling tower 2 roadways 3 aisles 4 Shaft 5 Buildings 6 support structure 7 System Piping 8 pipe parts 9 valves 10 Distribution Box 11 Surrounding buildings

Claims

1. Step 1: determining noise reduction targets within the functional areas and noise impact zones of the acoustic environment in which the cooling tower (1) is installed; Step 2: constructing a high-precision model of the cooling tower (1), a high-precision model of the system piping, and a high-precision model of the auxiliary components; Step 3: Based on the model constructed in step 2, continue to construct an engineering model including the terrain of the cooling tower (1) placement area, buildings (5), support structures (6), roadways (2), shafts (4), and passageways (3) to form a constraint model; Step 4: Continue to build an engineering model based on the constraint model, including the cooling tower (1) equipment, system piping (7), pipe components (8), valves (9), shock absorbers and distribution boxes (10), to form a functional model; Step 5: based on the functional model, construct a model of the surrounding building (11) and mark the locations of noise reduction targets in sensitive areas of the building to construct a target model; Step 6: based on the target model, lay out the cooling tower equipment in a modular form and install an inspection door at the same time; Step 7: Calculating the amount of superimposed noise of all cooling tower (1) module groups after the modular combination process of step 6; Step 8: Calculating the amount of noise to be processed that is transmitted to each sensitive point by the superimposed noises of the intake side, the shroud side, and the exhaust side of the cooling tower (1); Step 9: based on the amount of noise to be processed, setting a sound-absorbing structure for each cooling tower (1) of the target model after the modularized combination processing of step 6; Step 10: constructing a function model and performing data simulation to optimize the noise structure designed in step 9; and (11) constructing a cooling tower noise reduction equipment economic cost optimization model for the purpose of minimizing the economic cost of constructing the cooling tower (1) noise reduction equipment, and solving the model to obtain a cooling tower (1) noise reduction structural design scheme that optimizes the economic efficiency of the noise reduction equipment.

2. In step 9, the sound deadening structure is set as follows:

2. The noise reduction optimization method for a cooling tower based on a physical model according to claim 1, wherein a sound-absorbing louver with a built-in sound-absorbing insert is installed on the inlet side of the cooling tower (1), the length of the sound-absorbing louver is long enough to cover the length of the inlet of the cooling tower (1), the height is high enough to cover the height of the inlet of the cooling tower (1), the total area meets the intake requirements of the cooling tower (1), and the remaining part is a sound-insulating barrier, a completely sealed sound-insulating barrier is used on the side of the cooling tower (1), the sound-insulating barrier covers the cooling tower (1) arrangement area, and the top is flush with the exhaust outlet of the cooling tower (1), an openable inspection door is reserved in advance, and an inspection ladder is installed according to the restriction model, a silencer with a built-in sound-insulating insert is installed on the exhaust side of the cooling tower (1), a slow air flow area is secured between the silencer and the exhaust outlet of the cooling tower (1), and a flow guide plate is installed.

3. The specific process of step 10 is as follows: Step 10.1: Using equations (1) to (4), the amount of noise to be processed by the sound-reducing louver is calculated. 【number】 , the amount of noise to be treated by the silencer 【number】 , the intake coefficient I of the sound-absorbing louver Ａ , exhaust coefficient I Ｅ Calculate each of [Equation 1] [Equation 2] [Equation 3] [Equation 4] In formula (1), a ０ is the normal incidence sound absorption coefficient of the sound absorbing material, and Φ(a ０ ) is the sound absorption coefficient related to the normal incidence sound absorption coefficient of the sound absorbing material, and L Ａ is the effective sound-absorbing length of the sound-absorbing insert of the sound-absorbing louver, and L ｄ is the spacing between the sound-absorbing inserts of the sound-absorbing louver, and in equation (2), L Ｅ is the effective silencing length of the silencer insert, and M ｄ is the spacing between the silencer inserts, and in equation (3), L １ is the length of the sound-reducing louver, and L ｉ is the number of sound-absorbing inserts in the sound-absorbing louver, and A １ is the length of the inlet of the cooling tower (1), and A ｄ is the width of the inlet of the cooling tower (1), and A ｉ is the number of air inlets of each cooling tower (1), W is the number of cooling towers (1), K is the air intake coefficient of the cooling tower (1), and in equation (4), M １ is the length of the silencer, and M ｉ is the number of silencer silencer inserts, and E ｄ is the diameter of the cooling tower (1) exhaust port, and E ｉ is the number of outlets of each cooling tower (1), Using equations (5) and (6), the average inlet air velocity V Ａ and average exhaust wind speed V Ｅ Calculate each of [Equation 5] [Equation 6] In equations (5) and (6), Q is the air volume of one cooling tower (1), and using equations (7) and (8), the pressure loss of the silencer louver H Ａ and the pressure loss of the silencer H Ｅ Calculate each of [Equation 7] [Equation 8] In equations (7) and (8), ξ １ and ξ ２ are the local resistance coefficients, and ρ is the air density. Using equations (9) and (10), the regenerative noise L that needs to be considered at the cooling tower (1) exhaust outlet is calculated. Ｗ , exhaust air flow area S Ｅ Calculate, [Equation 9] [Equation 10] In equation (9), a is the regeneration coefficient, Step 10.2: Establishing a mutual control relationship between the effective sound-absorbing length and spacing of the sound-absorbing inserts of the sound-absorbing louvers that meets the noise target limits as follows: [0011] Establishing a mutual control relationship between the effective silencing length and spacing of the silencer's silencer inserts that meet the following noise target limits: [0012] Step 10.3: The mutual control relationship is taken as a mathematical model, and on the premise of meeting the noise reduction target limit value, L is calculated according to the optimization needs. Ａ and L ｄ and L Ｅ and M ｄ The cooling tower noise reduction optimization method based on a physical model according to claim 2, characterized in that the value trends of the cooling tower noise reduction optimization method are balanced and adjusted to achieve the optimization of the noise reduction structure.

4. The specific process of step 11 is as follows: Using the following equations (11), (12), and (13), the economic cost of constructing the silencer on the intake side, the economic cost of constructing the silencer on the exhaust side, and the economic cost of constructing the noise reduction equipment for the cooling tower (1) are calculated, respectively. [0013] [0014] [Equation 15] In formula (11), L Ａ Ｐｉ is the noise level of the ith sound-reducing louver, L eq is the specified noise limit value, r 1 is the distance from the sound receiving point 1 to the sound source, and r 2 is the distance from the sound receiving point 2 to the sound source. In equation (12), L Ｅ Ｐ is the superimposed noise of the silencer, and L Ｅ Ｐｉ is the noise amount of the ith silencer, N is the number of sound sources included in each group of cooling tower modules, D is the number of levels of noise energy increase when multiple cooling tower module groups are operating simultaneously, L eq is the specified noise limit value, r 1 is the distance from sound receiving point 1 to the sound source, r 2 is the distance from sound receiving point 2 to the sound source, and in equation (13), M is the economic cost of construction, X is the economic cost coefficient of construction, and d Ａ is the thickness of the sound-absorbing insert of the sound-absorbing louver, and d Ｅ is the thickness of the sound-deadening insert of the sound-deadening louver, Therefore, the economic cost optimization model for the cooling tower noise reduction equipment, which was constructed with the aim of minimizing the economic cost of constructing the cooling tower (1) noise reduction equipment, is shown in the following equation (14): [0016] In equation (14), V A is the average inlet air velocity, V E is the average exhaust air velocity, The decision variables in the economic cost optimization model for cooling tower noise reduction equipment include the effective silencing length of the silencer louvers, the spacing between the silencer inserts of the silencer louvers, the effective silencing length of the silencer and the spacing between the silencer inserts of the silencer; The cooling tower noise reduction optimization method based on a physical model as claimed in claim 3, characterized in that the economic cost optimization model of the cooling tower noise reduction equipment is then solved based on the Gurobii optimization solver under the optimization software platform, and a cooling tower noise reduction structural design scheme with the most economical and optimal noise reduction equipment is output.

5. The superimposed noise amount L Ｐ‘ is calculated using the following formula: [Equation 17] where N is the number of sound sources included in each group of cooling tower modules, D is the number of noise energy levels that increase when multiple cooling tower module groups are operating simultaneously, and L Ｐｉ The cooling tower noise reduction optimization method based on a physical model according to claim 1, characterized in that

6. The amount of noise to be processed in step 8 is calculated by the following formula: [Equation 18] [Equation 19] Here, L Ｐ‘ are the superimposed noise levels of the cooling tower module group, and L ｅｑ is the specified noise limit value, ΔL is the noise attenuation amount, and r １ is the distance from the receiving point 1 to the sound source, and r ２ 2. The noise reduction optimization method for a cooling tower based on a physical model according to claim 1, wherein:

7. 3. The noise reduction optimization method for a cooling tower based on a physical model according to claim 2, wherein the sound insulation barrier uses a 100mm thick modular sound screen panel with a sound insulation capacity of 24dB or more, the perforated panel uses a 0.8mm perforated aluminum plate, the sound absorption material uses a 100mm thick anti-corrosion, hydrophobic, non-flammable sound absorption cotton with a high sound absorption coefficient, a 2mm thick damping layer is used between the sound screen panel and the outer layer of galvanized steel plate, the inner frame of the sound absorption louver uses a hot-dip galvanized structure, and triangular flow guide plates are used on both ends of the silencer.

Images