A theoretical calculation method for the resistance loss of a deeply buried underground exhaust fan room

Abstract

The present invention discloses a theoretical calculation method for the resistance loss of an underground exhaust fan room in deep-buried space, which relates to the technical field of ventilation in underground space. Aiming at the problem that the air duct structure of the exhaust fan room in a pumped-storage power station is complex and difficult to calculate theoretically, the present invention proposes a reasonable correction coefficient to correct the theoretical calculation results, and determines the resistance of the exhaust fan room with different layout methods by combining theoretical calculation, numerical calculation and secondary correction, and gives a general calculation formula for the resistance loss of the exhaust fan room. At the same time, the present invention analyzes the influence of different fan opening methods on the resistance of the exhaust fan room when multiple fans are operating in parallel by means of theoretical formulas, overcoming the problem that the existing theoretical calculation methods are difficult to solve the resistance loss of complex air ducts. The present invention helps to provide guiding opinions for the selection of fan equipment in the exhaust fan room and simplifies the calculation amount of numerical simulation.

Description

Technical Field

[0001] The present invention belongs to the technical field of ventilation of underground spaces, and more specifically, relates to a theoretical calculation method for the resistance loss of an underground exhaust fan room in a deeply buried space. Background Art

[0002] The air distribution in a deeply buried underground space plays a crucial role in the safety of the space environment, and the exhaust system is a key link in the air distribution. Deeply buried underground spaces widely exist in cities (including subways, underground utility tunnels, underground warehouses), mines, pumped storage power stations (underground cavern groups), etc. Among them, the underground cavern group of a pumped storage power station belongs to a deeply buried underground building, and its main components include an underground ventilation duct such as a main power house, a busbar tunnel, a main transformer cavern, a traffic tunnel, a ventilation tunnel, etc. and an exhaust system. The ventilation and exhaust system of a pumped storage power station runs through the entire underground power house, and the exhaust system includes an exhaust lower horizontal tunnel, an exhaust vertical shaft, and an exhaust fan room. To meet the heat dissipation requirements of the power generation equipment in the main power house and each room, 4-5 axial flow exhaust fans need to be arranged in parallel inside the exhaust fan room. Some studies have shown that the energy consumption generated by the fans accounts for about 30-50% of the total building energy consumption. Therefore, the equipment selection of the fans is crucial. Selecting a too large model will cause unnecessary energy waste; selecting a too small model will make it difficult to meet the exhaust requirements; so a reasonable calculation method must be adopted to solve the resistance loss of the exhaust fan room in order to select the corresponding exhaust fan. At the same time, during the actual operation process, when multiple fans operate in parallel, although the total exhaust air volume increases, it is less than the sum of the exhaust air volumes of each fan when used alone, and the fan efficiency decreases. Therefore, it is very crucial to adopt a reasonable control method to reduce the mutual influence between the fans.

[0003] Regarding the calculation methods for the resistance loss of the exhaust fan room, there are mainly two types used in the design: the theoretical calculation method and the numerical simulation method. However, the following problems exist in the actual use of these two calculation methods:

[0004] 1) Due to the complex duct structure of the exhaust fan room, it is difficult to accurately solve the resistance loss of the exhaust fan room by the theoretical calculation method. Most of the designs use empirical values and estimate according to the loss of how many pascals per meter. Using the estimated results and referring to the relevant specifications for equipment selection, the result will lead to the actual exhaust air volume of the fan being far lower than the design value, and the actual operation effect will deviate greatly from the expected value.

[0005] 2) Use the method of numerical simulation to physically model the exhaust fan room, and then calculate the resistance loss of the exhaust fan room through simulation software such as Fluent. For different exhaust fan room structures, if you want to obtain the optimal solution, several physical models must be established, which requires a long time; moreover, due to problems such as the uncertainty of boundary conditions and the selection of turbulence models, when selecting equipment according to the calculation results of the resistance loss of the exhaust system calculated by the numerical simulation method, it will also lead to problems such as poor design and operation effects.

[0006] Among the existing patents on the influence of the operation effect of the whole-plant ventilation and exhaust system:

[0007] The invention patent with the application number 202010856702.5 proposes a method for studying the exhaust effect of the exhaust system of the underground powerhouse of a pumped-storage power station. This method takes the entire exhaust system as the research object and proposes a method for simulating indoor and outdoor meteorological parameters and deducing relevant parameters in the prototype through model tests when conducting model tests on the exhaust system. This patent provides a method for measuring the resistance loss of the exhaust system. However, it does not elaborate in detail on how to calculate the resistance loss of the exhaust fan room, and at the same time lacks an analysis of the factors affecting the exhaust effect.

[0008] The invention patent with the application number 202010284348.3 discloses a virtual actuator line method for simulating the working flow field of axial-flow exhaust fans in the underground powerhouse of a pumped-storage power station. This method uses the virtual actuator line model to numerically calculate the exhaust passage of the axial-flow exhaust fan in the pumped-storage power station. Although it solves the problem of a large number of grids and long calculation time when physically modeling the axial-flow exhaust fan in the underground powerhouse, it lacks theoretical calculation support and has less research on the control strategy when multiple fans operate in parallel.

[0009] When analyzing the exhaust effect of the exhaust fan room, due to a large number of operating generator sets, the exhaust air volume of a single fan during operation is difficult to meet the requirements. In actual projects, it is often necessary to start 2 - 4 fans. However, when the fans operate in parallel, although the air volume increases, it is less than the sum of the air supply volumes of each fan when used alone, and the fan efficiency decreases. Therefore, it is very crucial to adopt a reasonable control method to reduce the mutual influence between the fans. However, in the existing patents, there is a lack of research in this regard. In practice, the fan opening method often depends on experience or is randomly opened, resulting in low fan working efficiency and unnecessary energy waste. Summary of the Invention

[0010] The technical problem to be solved by the present invention is to provide a theoretical calculation method for the resistance loss of an underground exhaust fan room in a deep-buried space, which overcomes the problem that it is difficult to perform theoretical calculations due to the complex duct structure of the exhaust fan room in a pumped-storage power station.

[0011] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0012] Step 1: Reasonably simplify the model of the exhaust fan room. The specific method is as follows: For the irregular cross-sectional shape, simplify it by using the equivalent diameter method, simplify the upper arched cross-section (ceiling) into a horizontal surface, obtain the simplified physical model, and perform theoretical calculations on the physical model to obtain the resistance loss of the exhaust fan room.

[0013] Step 2: Perform numerical calculations on the simplified physical model to obtain the resistance loss of the exhaust fan room under the same conditions.

[0014] Step 3: Compare the results obtained from theoretical calculations and numerical calculations under the same conditions to obtain a numerical correction coefficient, and the numerical correction coefficient is used to correct the results obtained from numerical calculations.

[0015] Step 4: Perform numerical simulation calculations on the prototype of the exhaust fan room to obtain the resistance loss of the exhaust fan room in the prototype.

[0016] Step 5: Under the same conditions, compare the results obtained from numerical calculations of the simplified physical model of the exhaust fan room with the results obtained from numerical calculations in the prototype to obtain a model correction coefficient, and the model correction coefficient is used to correct the results obtained when performing numerical calculations using the physical model.

[0017] Step 6: According to the numerical correction coefficient and the model correction coefficient, correct the results of numerical calculations to obtain the theoretical calculation results of the resistance loss of the exhaust air system.

[0018] The calculation formula for obtaining the resistance loss of the exhaust fan room by theoretical calculation for the simplified physical model is:

[0019] ΔP L =S p Q 2 ,

[0020]

[0021] where, Δp L is the resistance loss of the exhaust fan room obtained by theoretical calculation for the physical model, S p is the pipeline impedance, Q is the volume flow rate in the pipeline, λ is the pipeline friction resistance coefficient, l is the pipeline length, d e is the equivalent diameter of the pipeline, A is the pipeline cross-sectional area, ε is the local resistance coefficient of the pipeline, and ρ is the density.

[0022] Preferably, when calculating the resistance loss of the prototype of the exhaust fan room by numerical calculation method, the specific operation steps are as follows:

[0023] S1. Establish a numerical calculation model of the prototype of the exhaust fan room;

[0024] S2. Take the actual exhaust fan room as the prototype, establish a scaled test bench for simulating the prototype, and establish a numerical calculation model for the scaled model test bench;

[0025] S3. Calculate the resistance loss of the prototype of the exhaust fan room according to the numerical calculation model of the exhaust fan room and the input boundary conditions:

[0026] S4. Calculate the resistance loss of the exhaust fan room of the scaled test bench according to the numerical calculation model of the scaled model test bench and the input boundary conditions;

[0027] S5. Compare the numerical calculation results of the prototype of the exhaust fan room and the scaled model test bench under the same conditions, and judge whether the difference between the two is within the error range. If it is within the error range, use the resistance loss of the prototype of the exhaust fan room as the result of the numerical calculation; if the two are not within the error range, modify the corresponding boundary conditions and return to step S3.

[0028] Preferably, the specific implementation manner of step S2 is:

[0029] Select the geometric similarity ratio, establish a scaled model test bench for simulating the prototype. When selecting the wall material of the scaled model test bench, the absolute roughness should be determined according to the geometric similarity ratio.

[0030] Obtain test data from the scaled model test bench, compare the calculation results of step S4, and judge whether the calculation results are within the error range. If they are not within the error range, the corresponding boundary conditions should be adjusted according to the similarity criterion to ensure the accuracy of the calculation results of the scaled model test bench.

[0031] Furthermore, the specific calculation steps of step six are:

[0032] First, perform theoretical calculation on the simplified physical model of the exhaust fan room to obtain the resistance loss ΔP of the exhaust fan room L ; perform numerical calculation on the simplified physical model of the exhaust fan room to obtain the resistance loss ΔP of the exhaust fan room under the same conditions s , and obtain the numerical correction coefficient ε1. The expression of the numerical correction coefficient ε1 is:

[0033] Then, perform numerical simulation calculation on the prototype of the exhaust fan room to obtain the resistance loss ΔP of the exhaust fan room in the prototype n , and under the same conditions, compare the result obtained by numerical calculation of the simplified physical model of the exhaust fan room with the result obtained by numerical calculation in the prototype to obtain the model correction coefficient ε2. The expression of the model correction coefficient ε2 is

[0034] Finally, according to the numerical correction coefficient ε1 and the model correction coefficient ε2, the numerical calculation result ΔP of the prototype of the exhaust fan room n is corrected to obtain the calculated result ΔP L ' of the resistance loss of the prototype of the exhaust fan room. The expression of the calculated result ΔP L ' of the resistance loss of the prototype of the exhaust fan room is: ΔP L ' = ε1ε2ΔP L .

[0035] After the numerical correction coefficient ε1 and the model correction coefficient ε2 are determined by the above method, they are only related to the characteristic curve of the exhaust system pipe network. For the control strategy of parallel operation of multiple fans, the technical route adopted by the present invention is:

[0036] When multiple fans are operating in parallel, the position unbalance rate η of the multiple fans is taken as the characteristic value. Different η values represent different fan opening modes. The expression of the position unbalance rate η is: where |Δd| is the relative position difference in the length direction between the center of the fan group and the center of the exhaust inlet, and L is the distance from the inlet of the exhaust fan room to the farthest end of the exhaust fan room.

[0037] The resistance of the exhaust fan room when multiple fans are operating in parallel is numerically calculated. The magnitude of the resistance loss when multiple fans are operating in parallel is compared, and the influence of the position unbalance rate η of the multiple fans on the resistance loss of the exhaust fan room is analyzed. The position unbalance rate η and the opening mode when multiple fans are operating in parallel will be presented in the form of a chart.

[0038] The beneficial effects of adopting the above technical solutions are as follows:

[0039] 1. A reasonable correction coefficient is proposed for the problem that the air duct structure of the exhaust fan room in the pumped-storage power station is complex and difficult to calculate theoretically. The theoretical calculation result is corrected, and a theoretical calculation method for the resistance loss of the exhaust fan room with different layout methods is determined by comprehensively considering theoretical formula calculation, numerical simulation analysis, and secondary correction method.

[0040] 2. The influence of different fan opening modes on the resistance of the exhaust fan room when multiple fans are operating in parallel is analyzed, overcoming the problem that it is difficult to solve the resistance loss of complex air ducts by the existing theoretical calculation methods. This method helps to provide guiding opinions for the selection of fan equipment in the exhaust fan room, and provides a scientific basis for reducing the resistance of the exhaust system and improving the ventilation energy-saving potential in the pumped-storage power station. Description of the Drawings

[0041] Figure 1 is the overall flowchart of the present invention;

[0042] Figure 2Axonometric drawing of the prototype of the exhaust fan room of Yimeng Pumped-storage Power Station in the embodiment;

[0043] Figure 3 Cross-sectional view of the exhaust air of the exhaust fan room of Yimeng Pumped-storage Power Station in the embodiment;

[0044] Figure 4 Axonometric drawing of the physical model after simplification of the pumped-storage power station in the embodiment;

[0045] Figure 5 Velocity distribution diagrams corresponding to different fan opening modes in the embodiment;

[0046] Figure 6 Pressure distribution diagrams corresponding to unbalance rates at different positions.

[0047] In the figure: 1. Exhaust air inlet; 2. Exhaust air duct; 3. First exhaust fan; 4. Second exhaust fan; 5. Third exhaust fan; 6. Fourth exhaust fan; 7. Exhaust shaft inlet; 8. Exhaust shaft. Specific implementation manners

[0048] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present application.

[0049] Referring to Figures 1-5 As shown, a theoretical calculation method for the resistance loss of the exhaust air system of an underground powerhouse in a deep-buried space includes the following steps:

[0050] Step 1: Simplify the exhaust fan room model to obtain a simplified physical model, and perform theoretical calculations on the physical model to obtain the resistance loss of the exhaust fan room;

[0051] Step 2: Perform numerical calculations on the simplified physical model to obtain the resistance loss of the exhaust fan room under the same conditions;

[0052] Step 3: Compare the calculation results obtained by theoretical formula calculation and numerical calculation under the same conditions to obtain a numerical correction coefficient, and the numerical correction coefficient is used to correct the results obtained by numerical calculation;

[0053] Step 4: Perform numerical simulation calculations on the prototype of the exhaust fan room to obtain the resistance loss of the exhaust fan room in the prototype;

[0054] Step 5. Under the same conditions, compare the results obtained by numerical calculation of the simplified physical model of the exhaust fan room with the results obtained by numerical calculation in the prototype to obtain a model correction coefficient, which is used to correct the results obtained when performing numerical calculation using the physical model;

[0055] Step 6. Correct the results of the numerical calculation according to the numerical correction coefficient and the model correction coefficient to obtain the theoretical calculation result of the resistance loss of the exhaust system.

[0056] Among them, simplifying the exhaust fan room to obtain a simplified physical model means that the parallel exhaust ducts in the prototype of the exhaust fan room are simplified into one exhaust duct, and the inlet 7 of the exhaust shaft is simplified into a 90° elbow, and its resistance is replaced by local resistance.

[0057] Furthermore, as a specific implementation manner, when performing theoretical calculation on the physical model of the exhaust fan room, the following operations will be performed:

[0058] Use theoretical calculation to obtain the resistance loss ΔPL of the exhaust fan room. The calculation formula for the resistance loss ΔPL is: ΔP L =S p Q 2 , where S p is the pipeline impedance, and Q is the volume flow rate in the pipeline. The calculation formula for the pipeline impedance S p is: Among them, λ is the pipeline friction resistance coefficient, l is the pipeline length, d e is the equivalent diameter of the pipeline, A is the pipeline cross-sectional area, ε is the local resistance coefficient of the pipeline, and ρ is the density.

[0059] Furthermore, as a specific implementation manner, when using the numerical calculation method to perform numerical calculation on the prototype of the exhaust fan room, its specific implementation manner is:

[0060] S1. Establish a numerical calculation model of the prototype of the exhaust fan room;

[0061] S2. Take the actual exhaust fan room as the prototype, establish a scaled test bench for simulating the prototype and establish a numerical calculation model of the scaled model test bench;

[0062] S3. Calculate the resistance loss of the prototype of the exhaust fan room according to the numerical calculation model of the exhaust fan room and the input boundary conditions:

[0063] S4. Calculate the resistance loss of the exhaust fan room of the scaled test bench according to the numerical calculation model of the scaled model test bench and the input boundary conditions;

[0064] S5. Compare the numerical calculation results of the prototype of the exhaust fan room and the scaled-down model test bench under the same conditions, and determine whether the difference between the two is within the error range. If it is within the error range, use the resistance loss of the prototype of the exhaust fan room as the result of the numerical calculation; if the two are not within the error range, modify the corresponding boundary conditions and return to step S3.

[0065] Further, the specific implementation of step S2 is as follows:

[0066] Select the geometric similarity ratio and establish a scaled-down model test bench for simulating the prototype. When selecting the wall material of the scaled-down model test bench, the absolute roughness should be determined according to the geometric similarity ratio.

[0067] Obtain the test data from the scaled-down model test bench, compare the calculation results in step S4, and determine whether the calculation results are within the error range. If they are not within the error range, the corresponding boundary conditions should be adjusted according to the similarity criterion to ensure the accuracy of the calculation results of the scaled-down model test bench.

[0068] Further, according to the numerical correction coefficient ε1 and the model correction coefficient ε2, correct the numerical calculation results to obtain the theoretical calculation results of the resistance loss of the exhaust system. The specific steps are as follows:

[0069] Conduct theoretical calculations on the simplified physical model of the exhaust fan room to obtain the resistance loss ΔP of the exhaust fan room L ; conduct numerical calculations on the simplified physical model of the exhaust fan room to obtain the resistance loss ΔP of the exhaust fan room under the same conditions s , and obtain the numerical correction coefficient ε1. The expression of the numerical correction coefficient ε1 is:

[0070] Further, conduct numerical simulation calculations on the prototype of the exhaust fan room to obtain the resistance loss ΔP of the exhaust fan room in the prototype n , and under the same conditions, compare the results obtained by numerical calculation of the simplified physical model of the exhaust fan room with the results obtained by numerical calculation in the prototype to obtain the model correction coefficient ε2. The expression of the model correction coefficient ε2 is:

[0071] Further, according to the numerical correction coefficient ε1 and the model correction coefficient ε2, correct the numerical calculation results ΔP of the prototype of the exhaust fan room n to obtain the calculated result ΔP of the resistance loss of the prototype of the exhaust fan room L ′. The expression of the calculated result ΔP of the resistance loss of the prototype of the exhaust fan room L ′ is: ΔP L ' = ε1ε2ΔP L .

[0072] Further, as a specific implementation, it also includes the control strategy for parallel operation of fans:

[0073] When multiple fans operate in parallel, the position unbalance rate η of multiple fans is taken as the characteristic value, and the expression of the position unbalance rate η is: Among them, |Δd| is the relative position difference in the length direction between the center of the fan group and the center of the exhaust inlet 1, and L is the distance from the inlet of the exhaust fan room to the farthest end of the exhaust fan room.

[0074] Furthermore, the resistance of the exhaust fan room when multiple fans operate in parallel is numerically calculated, and combined with the numerical correction coefficient ε1 and the model correction coefficient ε2, the resistance loss when multiple fans operate in parallel is obtained.

[0075] Furthermore, compare the magnitude of the resistance loss when multiple fans operate in parallel, and analyze the influence of the position unbalance rate η of multiple fans on the resistance loss of the exhaust fan room.

[0076] The present invention will be further described below in conjunction with the accompanying drawings of the specification and specific embodiments.

[0077] Aiming at the problems that it is difficult to solve in the prior art, such as the complex air duct structure of the exhaust fan room and it is difficult to accurately solve the resistance loss of the exhaust fan room by theoretical calculation methods. The present invention proposes a method that comprehensively considers theoretical formula calculation, numerical calculation, and secondary correction to determine the resistance loss of the exhaust fan room, and proposes a control strategy when multiple fans operate in parallel.

[0078] Taking a pumped-storage power station in Shandong as an example, its exhaust system mainly includes the underground power house exhaust shaft 8, the exhaust air duct 2 and the ground exhaust fan room platform. The underground power house exhaust shaft 8 is connected to the auxiliary power house ventilation machine room and the main transformer auxiliary power house ventilation machine room below, and is connected to the exhaust air duct 2 above. The cross-section is circular, with an inner diameter of 7.0m and a height of 208.87m. The exhaust air duct 2 is connected to the exhaust shaft 8 and the main exhaust fan room. The entrance of the exhaust air duct 2 is provided with the main exhaust fan room, and the cross-sectional net size is 7.0×6.0m, and the length of the hole is 377.30m. The elevation of the platform of the main exhaust fan room in the cross-section of the exhaust air duct 2 is 350.00m, and the platform size is 37.0×19.0m.

[0079] 1. Use the physical model obtained by simplifying the exhaust fan room through the existing theoretical experience formula calculation to obtain the resistance loss force ΔP of the exhaust fan room L .

[0080] ΔP L The calculation formula of is: ΔP L =S p Q 2 , where S p is the pipeline impedance, and Q is the volume flow rate in the pipeline. The calculation formula of the pipeline impedance S p is: Among them, λ is the friction coefficient along the pipeline, l is the pipeline length, d e is the equivalent diameter of the pipeline, A is the cross-sectional area of the pipeline, ε is the local resistance coefficient of the pipeline, and ρ is the density.

[0081] Furthermore, the calculation formula for the equivalent diameter d e of the pipeline is: Among them, A is the cross-sectional area of the pipeline, and χ is the wetted perimeter.

[0082] Furthermore, the local resistance coefficient ε of the pipeline includes the local resistance of sudden expansion and the local resistance coefficient ε2 of sudden contraction. The calculation formula for the local resistance coefficient ε1 of sudden expansion is: Among them, A1 is the cross-sectional area of the pipeline before diameter change, and A2 is the cross-sectional area of the pipeline after diameter change; the calculation formula for the local resistance coefficient ε2 of sudden contraction is: Among them, A1 is the cross-sectional area of the pipeline after diameter change, and A2 is the cross-sectional area of the pipeline before diameter change.

[0083] Furthermore, when the fluid flow state in the exhaust fan room is turbulent, the expression of its friction coefficient λ in different turbulent regions is:

[0084] Turbulent smooth zone:

[0085] Turbulent transition zone:

[0086] Turbulent rough zone:

[0087] In the above formula, Re is the Reynolds number; D is the equivalent diameter of the pipeline, with the unit of m; K is the absolute roughness of the wall surface, with the unit of mm. The wall surface structure of the exhaust fan room is a concrete pipe, and its K value is 0.3 - 3.0.

[0088] 2. On the premise that the boundary conditions of the theoretical formula are the same, use numerical calculation methods to calculate the resistance loss of the simplified exhaust fan room.

[0089] 3. Conduct theoretical calculations on the simplified physical model of the exhaust fan room to obtain the resistance loss ΔP L of the exhaust fan room; conduct numerical calculations on the simplified physical model of the exhaust fan room to obtain the resistance loss ΔP s of the exhaust fan room under the same conditions, and obtain the numerical correction coefficient ε1. The expression of the numerical correction coefficient ε1 is:

[0090] 4. Furthermore, conduct numerical simulation calculations on the prototype of the exhaust fan room to obtain the resistance loss ΔP n, under the same conditions, the model correction coefficient ε2 is obtained by comparing the results obtained from the numerical calculation of the simplified exhaust fan room physical model with those obtained from the numerical calculation of the prototype. The expression of the model correction coefficient ε2 is as follows:

[0091] 5. Further, according to the numerical correction coefficient ε1 and the model correction coefficient ε2, the numerical calculation result ΔP of the exhaust fan room prototype n is corrected to obtain the calculated result ΔP L ' of the resistance loss of the exhaust fan room prototype. The expression of the calculated result ΔP L ' of the resistance loss of the exhaust fan room prototype is: ΔP L ' = ε1ε2ΔP L .

[0092] To ensure the accuracy of the numerical calculation results, especially when numerically calculating the exhaust fan room prototype, the accuracy of its results directly affects the accuracy of the numerical correction coefficient ε1. The accuracy of the numerical calculation method of the present invention can be ensured through the following steps:

[0093] 1). Establish a numerical calculation model of the exhaust fan room prototype;

[0094] 2). Taking the actual exhaust fan room as the prototype, select an appropriate geometric similarity ratio, build a scaled test bench for simulating the prototype, select materials with corresponding roughness to the prototype according to the similarity ratio, and establish a numerical calculation model of the scaled model test bench;

[0095] 3). Since the proportions of inertial force and buoyancy force of the prototype and the scaled model are different, when establishing the scaled model, consider the larger value of the influencing factors of the two, and use the larger value as the decisive influencing factor;

[0096] 4). Calculate the resistance loss of the exhaust fan room of the scaled test bench according to the numerical calculation model of the scaled model test bench and the input boundary conditions;

[0097] 5). Compare the numerical calculation results of the exhaust fan room prototype and the scaled model test bench under the same conditions, and judge whether the difference between the two is within the error range. If it is within the error range, use the resistance loss of the exhaust fan room prototype as the numerical calculation result; if the two are not within the error range, modify the corresponding boundary conditions and return to step 2.

[0098] For the numerical calculation results under each working condition, they are verified by the experimental data obtained from the scaled model of the corresponding working condition to ensure the reliability of the results.

[0099] Obtain test data from the scaled model test bench, compare with the calculation results in step 4, and determine whether the calculation results are within the error range. If not, the corresponding boundary conditions should be adjusted according to the similarity criterion to ensure the accuracy of the calculation results of the scaled model test bench.

[0100] Furthermore, the settlement results of the above method are as follows:

[0101]

[0102] Furthermore, in the embodiment, it also includes a control strategy for parallel operation of fans, and the specific content is as follows:

[0103] When multiple fans operate in parallel, take the position imbalance rate η of multiple fans as the characteristic value, and the expression of the position imbalance rate η is: Where, |Δd| is the relative position difference in the length direction between the center of the fan group and the center of the exhaust inlet 1, and L is the distance from the inlet of the exhaust fan room to the farthest end of the exhaust fan room.

[0104] The specific number of fans and their opening conditions are shown in Table 1:

[0105] Table 1 Specific number of fans and their opening conditions

[0106]

[0107]

[0108] (Note: In the table, the fan is turned on as 1; the fan is turned off as 0)

[0109] Furthermore, perform numerical calculation on the resistance of the exhaust fan room when multiple fans operate in parallel, and combine the numerical correction coefficient ε1 and the model correction coefficient ε2 to obtain the resistance loss when multiple fans operate in parallel.

[0110] Furthermore, compare the magnitudes of the resistance losses when multiple fans operate in parallel, and analyze the influence of the position imbalance rate η of multiple fans on the resistance loss of the exhaust fan room.

[0111] Figure 6 It is the pressure distribution diagram corresponding to different position imbalance rates.

[0112] The above is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered within the protection scope of the present invention.

Claims

1. A theoretical calculation method for the resistance loss of an underground exhaust fan room in deep - buried space, characterized in that, It includes the following steps: Step 1: Simplify the model of the exhaust fan room to obtain a simplified physical model, and perform theoretical calculations on the physical model to obtain the resistance loss of the exhaust fan room; Step 2: Perform numerical calculations on the simplified physical model to obtain the resistance loss of the exhaust fan room under the same conditions; Step 3: Compare the results obtained from theoretical calculations and numerical calculations under the same conditions to obtain a numerical correction coefficient, which is used to correct the results obtained from numerical calculations; Step 4: Perform numerical simulation calculations on the prototype of the exhaust fan room to obtain the resistance loss of the exhaust fan room in the prototype; Step 5: Under the same conditions, compare the results obtained from numerical calculations of the simplified physical model of the exhaust fan room with the results obtained from numerical calculations in the prototype to obtain a model correction coefficient, which is used to correct the results obtained from numerical calculations using the physical model; Step 6: Correct the results of numerical calculations according to the numerical correction coefficient and the model correction coefficient to obtain the theoretical calculation results of the resistance loss of the exhaust air system; In the above Step 4, when calculating the resistance loss of the prototype of the exhaust fan room using the numerical calculation method, the specific operation steps are as follows: S1: Establish a numerical calculation model of the prototype of the exhaust fan room; S2: Take the actual exhaust fan room as the prototype, establish a scaled-down model test bench for simulating the prototype, and establish a numerical calculation model of the scaled-down model test bench; S3: Calculate the resistance loss of the prototype of the exhaust fan room according to the numerical calculation model of the exhaust fan room and the input boundary conditions; S4: Calculate the resistance loss of the exhaust fan room of the scaled-down model test bench according to the numerical calculation model of the scaled-down model test bench and the input boundary conditions; S5: Compare the numerical calculation results of the prototype of the exhaust fan room and the scaled-down model test bench under the same conditions, and judge whether the difference between the two is within the error range. If it is within the error range, take the resistance loss of the prototype of the exhaust fan room as the result of numerical calculation; if the two are not within the error range, modify the corresponding boundary conditions and return to Step S3; The specific implementation method of the above S2 is as follows: Select the geometric similarity ratio, establish a scaled-down model test bench for simulating the prototype. When selecting the wall material of the scaled-down model test bench, the absolute roughness should be determined according to the geometric similarity ratio; Obtain test data from the scaled-down model test bench, compare the calculation results of the above Step S4, and judge whether the calculation results are within the error range. If they are not within the error range, the corresponding boundary conditions should be adjusted according to the similarity criterion to ensure the accuracy of the calculation results of the scaled-down model test bench.

2. The theoretical calculation method for the resistance loss of an underground exhaust fan room in deep-buried space according to claim 1, wherein The specific calculation steps of the above Step 6 are as follows: First, perform theoretical calculations on the simplified physical model of the exhaust fan room to obtain the resistance loss ΔP of the exhaust fan room L ; perform numerical calculations on the simplified physical model of the exhaust fan room to obtain the resistance loss ΔP of the exhaust fan room under the same conditions s ; Obtain the numerical correction coefficient ε1, and the expression of the numerical correction coefficient ε1 is as follows: Then, a numerical simulation calculation is carried out on the prototype of the exhaust fan room to obtain the resistance loss ΔP of the exhaust fan room in the prototype n , under the same conditions, the model correction coefficient ε2 is obtained by comparing the results obtained by numerical calculation of the simplified physical model of the exhaust fan room with the results obtained by numerical calculation in the prototype. The expression of the model correction coefficient ε2 is Finally, according to the numerical correction coefficient ε1 and the model correction coefficient ε2, the numerical calculation result ΔP of the prototype of the exhaust fan room n is corrected to obtain the calculated result ΔP L ′ of the resistance loss of the prototype of the exhaust fan room. The expression of the calculated result ΔP L ′ of the resistance loss of the prototype of the exhaust fan room is: ΔP L ′ = ε1ε2ΔP L .

3. The theoretical calculation method for the resistance loss of an underground exhaust fan room in deep-buried space according to claim 2, characterized in that, Utilize the numerical correction coefficient ε1 and the model correction coefficient ε2 to analyze the control mode when multiple fans are operating in parallel, and obtain the relationship between the resistance loss of the exhaust fan room, the numerical correction coefficient ε1, the model correction coefficient ε2, and the position imbalance rate η when multiple fans are operating in parallel.

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