Gas and power pipeline coupling simulation device and method based on size reduction

Abstract

The invention discloses a gas and power pipeline coupling simulation device and method based on size reduction, belongs to the technical field of gas safety, and solves the problems of high time, manpower and material resource cost consumed by full-size experiment research of gas and power pipeline coupling risks in the prior art. According to the experimental device for simulating gas leakage to the power pipeline, the coupling effect can be studied and evaluated, the cost can be saved by carrying out the coupling experimental research of reducing the size, and the risk possibly caused by gas leakage in the power pipeline can be more conveniently understood and predicted; scientific basis is provided for formulating related safety standards and protective measures, scientific basis and technical support are provided for safety management of a gas pipeline leakage diffusion and cable trench coupling system, and improvement of the overall safety of urban energy infrastructures is facilitated.

Description

Technical Field

[0001] The invention belongs to the technical field of gas safety, and relates to a gas and power pipeline coupling simulation device and method based on reduced size. Background Art

[0002] In the construction of modern urban infrastructure, gas pipelines and power pipelines, as important energy and power transmission channels, are usually densely arranged in the city's underground pipe network system. However, due to the limitations of urban space and the layout requirements of integrated pipe corridors, the distance between gas pipelines and power pipelines is sometimes difficult to maintain within a safe range, and there are many parallel laying of gas and power pipelines, resulting in the coupling risk of gas leakage to power pipelines.

[0003] Gas pipelines are usually made of metal or polyethylene (PE) materials and are used to transport flammable gases such as natural gas and liquefied petroleum gas. Due to the flammable and explosive characteristics of gas, the design and construction of gas pipelines strictly follow relevant safety standards. However, with the increase in the service life of the pipeline, external force damage, corrosion, geological movement and other factors, gas pipelines may leak, especially in urban old pipeline areas, where the risk of pipeline leakage is high. Power pipelines are mainly used to transport high-voltage or ultra-high-voltage electricity, and usually contain cable trenches, tunnels or pipe galleries, with cables laid inside. With the increase in electricity demand, the voltage level of power pipelines continues to increase. Although the design of its external protective layer can effectively resist external physical damage, there is still a risk of cable damage due to corrosion, mechanical damage or other reasons. There is a strong electric field around high-voltage cables, so when laying power pipelines in parallel with other pipelines, special consideration should be given to electromagnetic compatibility and insulation protection.

[0004] Gas pipelines and power pipelines are often close to each other in urban underground spaces, and are sometimes laid in parallel. This arrangement brings about the risk of gas leaking into power pipelines. When gas leaks, the leaked gas may penetrate into adjacent power pipelines through damaged pipes or joints, forming flammable gas accumulation. If arcs or short circuits occur in the power pipelines, explosions may occur, causing serious loss of life and property. At present, the safety research and management technology for gas pipelines and power pipelines are relatively mature, but there is still little research on the risks of the two in a coupled environment.

[0005] For example, the invention patent with application publication number CN111122067A discloses a gas pipeline gas leakage simulation device, which uses a high-speed camera to dynamically shoot the diffusion cloud, and uses a gas concentration monitoring sensor array to dynamically monitor and record the diffusion gas concentration, so as to obtain the real and effective dynamic changes in the diffusion range of the gas pipeline leakage, so as to provide more accurate reference data for the safety prevention and control and emergency decision-making of pipeline gas leakage accidents. However, although it discloses a gas pipeline leakage simulation device, it does not take into account the coupling of the simulated gas and power pipelines.

[0006] For example, the invention patent with application publication number CN113947325A discloses a coupling risk simulation test bench for power cable channels and municipal gas pipelines. By setting gas pipelines and power cable channel models in the soil of the coupling test box, a coupling risk simulation experiment between power cable channels and municipal gas pipelines is carried out. However, its research purpose focuses on the experimental exploration of gas and power pipelines in underground environments. Its power pipeline simulation device is not flexible in adjustment, and there are few gas leaks, which is not variable. It can be seen that scientific research institutes have built full-scale underground pipeline coupling risk test benches, including municipal gas, water supply, heat and other underground pipelines.

[0007] With the complexity and aging of urban underground pipelines, the coupling risk between gas pipelines and power pipelines has become increasingly prominent. However, based on the existing technologies, it is found that the time, manpower and material costs of conducting full-scale experiments are extremely high. How to design a simulation device that can replace the full-scale experiment to study the coupling risk of gas leakage and power pipelines, and how to explore its risk threshold to provide a reference for the formulation of relevant standards have become urgent problems to be solved in the simulation experiment of the coupling risk of municipal gas pipeline leakage diffusion and cable trench system. Summary of the invention

[0008] The technical solution of the present invention is used to solve the problem of high time, manpower and material costs in full-scale experimental research on the coupling risks of gas and power pipelines under the existing technology.

[0009] The present invention solves the above technical problems through the following technical solutions:

[0010] A gas and power pipeline coupling simulation device based on reduced size, including a soil environment module, a power channel module, a gas leakage detection module and a gas diffusion detection module;

[0011] The soil environment module comprises a soil box, wherein the soil box is filled with soil;

[0012] The power conduit module comprises a cable trench, a ventilation duct, an infiltration port and a control switch; the power conduit module is arranged in a soil box, ventilation ducts are arranged at both ends of the cable trench, the vents of the ventilation ducts are located on the soil surface, a plurality of infiltration ports are arranged on different sides of the cable trench, and the control switch is arranged on the infiltration port;

[0013] The gas leakage detection module comprises a gas pipeline, a high-pressure gas storage tank, a pressure regulating valve, a flow meter, a main pipe ball valve, a branch pipe ball valve and a leakage nozzle; the high-pressure gas storage tank, the pressure regulating valve, the flow meter and the main pipe ball valve are connected in sequence through the gas pipeline, the output end of the main pipe ball valve is respectively connected to the input ends of the plurality of branch pipe ball valves, the output end of the branch pipe ball valve is connected to the input end of the leakage nozzle, the branch pipe ball valve and the leakage nozzle are arranged in a soil box, the output end of the leakage nozzle serves as a leakage port, the plurality of leakage nozzles are respectively arranged on different sides of the cable trench, and the coupling spacing between the gas pipeline and the cable trench is controlled by adjusting the length of the leakage nozzle;

[0014] The gas diffusion detection module includes a gas detection concentration sensor, a data acquisition unit and a computer; the gas detection concentration sensor is arranged at the infiltration entrance of the power pipeline module, the input end of the data acquisition unit is respectively connected to the output ends of multiple gas detection concentration sensors, and the output end of the data acquisition unit is connected to the computer.

[0015] Furthermore, the soil is sandy soil, clay or loam, and the soil box has a length of 5 m, a width of 3 m and a height of 1.2 m.

[0016] Furthermore, the cable trench is a rectangular stainless steel pipe with a length of 3m, a width of 0.3m and a height of 0.3m.

[0017] Furthermore, the coupling mode between the cable trench and the gas pipeline is parallel coupling or cross coupling, and the coupling distance between the cable trench and the gas pipeline is adjustable.

[0018] Furthermore, the length of the leakage nozzle is adjustable, and the coupling distance between the cable trench and the gas pipeline can be adjusted by changing the length of the leakage nozzle.

[0019] Furthermore, the diameter of the gas pipeline is 20 mm, and the diameter of the leakage nozzle is any one of 20 mm, 32 mm and 40 mm.

[0020] The present invention also provides a gas and power pipeline coupling simulation method based on reduced size, comprising the following steps:

[0021] S1. Collect prototype parameters of the actual gas pipeline network and power pipeline site; the prototype parameters include geometric dimensions, leakage source parameters, environmental parameters and critical space state; the geometric dimensions include electrical pipeline dimensions, gas pipeline dimensions and coupling spacing; the leakage source parameters include leakage port area, leakage flow rate, leakage flow rate and diffusion coefficient; the environmental parameters include wind speed, temperature and pressure; the critical space state includes soil characteristics and relative position;

[0022] S2, scaling the prototype parameters to the scaled-down experimental model parameters based on similarity theory design;

[0023] S21. Using geometric similarity as the similarity criterion, the electrical pipeline size, gas pipeline size and coupling spacing are scaled;

[0024] S22, using the Froude number as the similarity criterion, scaling the leakage velocity, leakage port area and leakage flow rate;

[0025] S23, using the Peclet number as the similarity criterion, the diffusion coefficient is scaled;

[0026] S3. Build a scaled-down experimental model to conduct a gas and power pipeline coupling risk experiment;

[0027] S4. Based on the similarity principle, the gas and power pipeline coupling risk experimental data are converted into field data, compared with the theoretical prediction data, and the gas and power pipeline coupling risk experiment is evaluated.

[0028] Furthermore, in step S21, the electrical pipeline size, the gas pipeline size and the coupling spacing are scaled based on geometric similarity as the similarity criterion as follows:

[0029] Use the following formula to scale electrical conduit sizes:

[0030] L m =λL o

[0031] Where, L m represents the electrical conduit size of the experimental model, L o represents the electrical conduit size of the prototype, λ represents the geometric scale factor, and the similarity ratio of the electrical conduit size is λ;

[0032] Use the following formula to scale the gas pipeline size:

[0033] l m =λl o

[0034] In the formula, l m represents the gas pipeline size of the experimental model, l orepresents the gas pipeline size of the prototype, and the similarity ratio of the gas pipeline size is λ;

[0035] The coupling spacing is scaled using the following formula:

[0036] d m =λd o

[0037] Where, d m represents the coupling distance of the experimental model, d o represents the coupling spacing of the prototype, and the similarity ratio of the coupling spacing is λ.

[0038] Furthermore, in step S22, the leakage velocity, leakage port area and leakage flow rate are scaled using the Froude number as the similarity criterion as follows:

[0039] The leakage flow rate is scaled using the following formula:

[0040] v m =λ 0.5 v o

[0041] In the formula, v m represents the leakage flow rate of the experimental model, v o represents the leakage flow rate of the prototype, and the similarity ratio of the leakage flow rate is λ 0.5 ;

[0042] The leak area is scaled using the following formula:

[0043] A m =λ 2 A o

[0044] In the formula, A m Represents the leakage area of ​​the experimental model, A o represents the leakage area of ​​the prototype, and the similarity ratio of the leakage area is λ 2 ;

[0045] The leakage flow is scaled using the following formula:

[0046] Q m =λQ o

[0047] In the formula, Q m represents the leakage flow of the experimental model, Q o represents the leakage flow of the prototype, and the similarity ratio of the leakage flow is λ 2.5 .

[0048] Furthermore, in step S23, the diffusion coefficient is scaled using the Peclet number as a similarity criterion as follows:

[0049] The diffusion coefficient is scaled using the following formula:

[0050] D m =λ 1.5 D o

[0051] Where D m represents the diffusion coefficient of the experimental model, D o represents the diffusion coefficient of the prototype, and the similarity ratio of the diffusion coefficient is λ 1.5 .

[0052] The advantages of the present invention are:

[0053] (1) The present invention designs a gas and power pipeline coupling simulation device based on reduced size, which can study and evaluate the coupling effect of gas and power pipelines. Carrying out reduced-size coupling experimental research can save costs, more conveniently understand and predict the risks that may be caused by gas leakage in power pipelines, and provide a scientific basis for the formulation of relevant safety standards and protective measures. It also provides a scientific basis and technical support for the safe management of gas pipeline leakage diffusion and cable trench coupling systems, which helps to improve the overall safety of urban energy infrastructure.

[0054] (2) The present invention can adjust various conditions such as leakage rate, coupling spacing, soil environment, and coupling mode of gas and power channels, and provide experimental support for the risk of gas leakage and power channel coupling. It has the advantages of low experimental cost and strong operability, and is suitable for gas diffusion risk research in different scenarios.

[0055] (3) The present invention can adjust the coupling distance between the gas and power pipelines. Since the gas diffuses into the soil through the gas pipeline, the coupling distance between the leakage port and the power pipeline will affect the diffusion characteristics of the gas to the power pipeline, and the resulting coupling risks are also different. Since it is difficult to change the coupling distance with the power pipeline after the gas pipeline is laid, it is difficult to simulate the coupling risks under different coupling distances. The present invention adjusts the length of the leakage nozzle to change the distance between the leakage port of the gas pipeline and the power pipeline, thereby simulating the effect of leakage ports with different spacings on the coupling risk of the power pipeline.

[0056] (4) The present invention designs a scaled-down experimental model based on the similarity principle. By controlling the proportional relationship between different parameters, the diffusion process of gas in the scaled-down experimental model is made similar to the physical process of actual leakage. The prototype parameters are converted from aspects such as geometric similarity, Froude number, and Peclet number to characterize the similarity relationship between the experimental model and the prototype. A scaled-down gas and power pipeline coupling risk experimental model is built to restore the gas leakage and diffusion conditions of the actual gas network and power pipeline site, study the gas and power pipeline coupling risk conditions, and use the conclusions of the scaled-down experiment to reflect the leakage and diffusion characteristics of gas in actual scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 It is a side view of a gas and power pipeline coupling simulation device based on reduced size according to the first embodiment of the present invention;

[0058] Figure 2 is a top view of a gas and power pipeline coupling simulation device based on reduced size according to the first embodiment of the present invention;

[0059] FIG3( a ) is a front view of the simulation device when the leakage port is arranged above the power pipeline according to the first embodiment of the present invention;

[0060] FIG3( b ) is a front view of the simulation device when the leakage port is arranged on the side of the power pipeline according to the first embodiment of the present invention;

[0061] FIG3( c ) is a front view of the simulation device when the leakage port is arranged below the power pipeline according to the first embodiment of the present invention;

[0062] Figure 4 is a flow chart of a gas and power pipeline coupling simulation method based on reduced size according to Embodiment 1 of the present invention;

[0063] Figure numerals: 11, soil box; 21, cable trench; 22, ventilation duct; 23, infiltration port; 31, gas pipeline; 32, high-pressure gas storage tank; 33, pressure regulating valve; 34, flow meter; 35, main pipe ball valve; 36, branch pipe ball valve; 37, leakage nozzle; 41, gas detection concentration sensor; 42, data acquisition unit; 43, computer. DETAILED DESCRIPTION

[0064] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0065] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and specific embodiments:

[0066] Embodiment 1

[0067] like Figure 1-2 As shown, specifically, a gas and power pipeline coupling simulation device based on reduced size is disclosed, including a soil environment module, a power channel module, a gas leakage detection module and a gas diffusion detection module;

[0068] The soil environment module comprises a soil box 11, and the soil box 11 contains soil;

[0069] Specifically, the soil is soil of different soil types such as sand, clay or loam, which is used to simulate different soil environments and study the impact of soil on gas leakage.

[0070] In this embodiment, the soil box 11 has a length of 5 m, a width of 3 m, and a height of 1.2 m, and the soil box 11 is arranged indoors to prevent rainwater from seeping in and to avoid the influence of external factors such as wind speed.

[0071] This embodiment uses local expanded clay soil samples as an alternative diffusion medium. Before the soil is buried in the soil box 11, the clay is first screened and prepared to remove large particles of stone and soil lumps in the clay. The soil is then buried layer by layer, and artificial compaction is performed every 30 cm to ensure the uniformity of the experimental soil environment.

[0072] The power conduit module includes a cable trench 21, a ventilation duct 22, an infiltration port 23 and a control switch (not shown); the power conduit module is arranged in a soil box 11, and ventilation ducts 22 are respectively arranged at both ends of the cable trench 21, and the ventilation openings of the ventilation duct 22 are located on the soil surface. The multiple infiltration ports 23 are respectively arranged on different sides of the cable trench 21, and the control switch is arranged on the infiltration port 23.

[0073] In this embodiment, the power pipeline module is used to simulate the power pipeline structure and its coupling relationship with the gas pipeline 31; infiltration ports 23 are provided on the four sides of the cable trench 21, as shown in FIG3(b), and each control switch individually controls the infiltration port 23 at the corresponding position, so as to explore the gas diffusion characteristics at different leakage ports and infiltration point coupling positions.

[0074] Furthermore, the infiltration port 23 is provided with a mesh cover to prevent the power pipeline module from being infiltrated by the soil after being buried in the soil;

[0075] In this embodiment, the cable trench 21 is a rectangular stainless steel tube with a length of 3 m, a width of 0.3 m, and a height of 0.3 m.

[0076] In this embodiment, the ventilation opening of the ventilation duct 22 is used to connect the power pipeline buried in the soil with the outdoor atmosphere. The ventilation opening of the ventilation duct 22 can be used as an entrance for arranging gas detection equipment. The length of the ventilation duct 22 is 0.3m, the width is 0.2m, and the height is 0.2m.

[0077] The gas leakage detection module includes a gas pipeline 31, a high-pressure gas storage tank 32, a pressure regulating valve 33, a flow meter 34, a main pipe ball valve 35, a branch pipe ball valve 36 and a leakage nozzle 37; the high-pressure gas storage tank 32, the pressure regulating valve 33, the flow meter 34, and the main pipe ball valve 35 are connected in sequence through the gas pipeline 31, the output end of the main pipe ball valve 35 is respectively connected to the input end of the plurality of branch pipe ball valves 36, the output end of the branch pipe ball valve 36 is connected to the input end of the leakage nozzle 37, the branch pipe ball valve 36 and the leakage nozzle 37 are arranged in the soil box 11, the output end of the leakage nozzle 37 is used as a leakage port, and the plurality of leakage nozzles 37 are respectively arranged on different sides of the cable trench 21, and the coupling spacing between the gas pipeline 31 and the cable trench 21 is controlled by adjusting the length of the leakage nozzle 37;

[0078] Furthermore, the high-pressure gas storage tank 32 is provided with fuel gas. Since natural gas is flammable and explosive, in this embodiment, the experimental gas in the fuel gas high-pressure gas storage tank 32 adopts 80% methane standard gas with a lower explosion limit (a mixture of 4% vol methane and 96% vol nitrogen) to ensure experimental safety. At the same time, the fuel gas concentration data obtained by monitoring can be proportionally amplified to obtain the actual fuel gas concentration value.

[0079] Furthermore, the flow meter 34 is used to record the gas leakage amount, and the pressure regulating valve 33 is used to adjust and record the gas leakage pressure to ensure that the gas is in a stable leakage state or is adjusted to the corresponding experimental working condition through the pressure relief valve to meet the experimental requirements.

[0080] In this embodiment, the gas leakage detection module is used to simulate the leakage of the gas pipeline 31 and adjust the gas leakage rate; after the gas is released from the high-pressure gas storage tank 32, it passes through the pressure regulating valve 33, and the flow and pressure in the main pipe of the gas pipeline 31 are controlled by adjusting the opening of the main pipe ball valve 35, and the gas leakage flow and pressure in each branch pipe are controlled by adjusting the opening of the branch pipe ball valve 36. The gas leaks into the soil through the leakage nozzle 37, simulating the coupling risk of gas diffusion under different leakage rates;

[0081] Furthermore, the coupling mode between the cable trench 21 and the gas pipeline 31 is parallel coupling or cross coupling, and the coupling distance between the cable trench 21 and the gas pipeline 31 is adjustable.

[0082] Furthermore, the length of the leakage nozzle 37 is adjustable, and the coupling distance between the cable trench 21 and the gas pipeline 31 can be adjusted by changing the length of the leakage nozzle 37 .

[0083] Furthermore, the diameter of the gas pipeline 31 is 20 mm, and the diameter of the leakage nozzle 37 is any one of 20 mm, 32 mm and 40 mm.

[0084] As shown in Figure 3(a)-(c), this embodiment provides three gas pipeline 31 branches, which are respectively arranged above, on the side and below the cable trench 21. The gas pipeline 31 branches located above and below the cable trench 21 are laid in a cross-arrangement with the cable trench 21 to simulate a cross-coupling scenario; the gas pipeline 31 branch located on the side of the cable trench 21 is laid in parallel with the cable trench 21 to simulate a parallel coupling scenario.

[0085] In this embodiment, the gas leak detection module can also be used to adjust the coupling distance between the gas and the power pipeline; since the gas diffuses into the soil through the gas pipeline 31, the coupling distance between the leakage port and the power pipeline will affect the diffusion characteristics of the gas to the power pipeline, and the resulting coupling risks are also different. Since it is difficult to change the coupling distance with the power pipeline after the gas pipeline 31 is laid, it is difficult to simulate the coupling risks under different coupling distances. In this embodiment, by adjusting the length of the leakage nozzle 37, the distance between the leakage port of the gas pipeline 31 and the power pipeline is changed to simulate the effect of leakage ports with different spacings on the coupling risk of the power pipeline.

[0086] The gas diffusion detection module includes a gas detection concentration sensor 41, a data acquisition unit 42 and a computer 43; the gas detection concentration sensor 41 is arranged at the infiltration inlet 23 of the power pipeline module, the input end of the data acquisition unit 42 is respectively connected to the output ends of multiple gas detection concentration sensors 41, and the output end of the data acquisition unit 42 is connected to the computer 43.

[0087] In this embodiment, the gas diffusion detection module is used to collect and analyze the gas diffusion situation. Specifically, a plurality of the gas detection concentration sensors 41 are arranged in the soil outside the infiltration port 23 to detect the point concentration change of the gas when it diffuses in the soil.

[0088] Furthermore, a plurality of the gas detection concentration sensors 41 can be arranged at different positions of the power pipeline module to form a multi-point detection network to monitor the concentration distribution of gas diffusion in real time.

[0089] Specifically, the model of the gas detection concentration sensor 41 is FGA1000L, the measurement range is 0-100vo1%, and the measurement accuracy is 0.5%FS.

[0090] Furthermore, the gas diffusion detection module further includes a gas concentration detector and a gas monitor (not shown), the gas concentration detector is arranged at the vent of the ventilation duct 22, and the gas monitor is arranged in the soil outside the cable trench 21. In this embodiment, the gas concentration detector adopts Huarui methane concentration detector, the gas concentration detector model is ZNRQ200L, the test range is 0-20% vol, the measurement accuracy is 0.01% vol, and it is used to monitor the diffusion law of gas leakage in the soil environment.

[0091] The present invention also provides a gas and power pipeline coupling simulation method based on reduced size, comprising the following steps:

[0092] S1. Collect prototype parameters of the actual gas pipeline network and power pipeline site; the prototype parameters include geometric dimensions, leakage source parameters and environmental parameters;

[0093] Specifically, the geometric dimensions include electrical pipeline dimensions, gas pipeline dimensions and coupling spacing; the leakage source parameters include leakage port area, leakage flow rate, leakage flow rate and diffusion coefficient; and the environmental parameters include wind speed, temperature and pressure.

[0094] Furthermore, the prototype parameters also include critical spatial states, and the critical spatial states include soil properties and relative positions.

[0095] In this embodiment, the relative position refers to the relative position of the gas pipeline and the power channel. The relative position of the gas and power pipelines includes parallel and cross, which is represented by the relative position of the gas leakage port and the power channel in the coupling test. As shown in Figure 3(a)-(c), the relative position of the leakage port and the power channel includes the gas leakage port (leakage nozzle) simulating parallel laying on the side of the power channel and the leakage port (leakage nozzle) simulating cross laying above and below the power channel.

[0096] Since the diffusion process of gas in soil and power channels after leakage is affected by many factors, such as gas concentration gradient, diffusion coefficient, resistance coefficient, soil texture, soil bulk density and soil porosity, soil properties are also important physical parameters for studying gas diffusion.

[0097] S2, scaling the prototype parameters to the scaled-down experimental model parameters based on similarity theory design;

[0098] The similarity principle refers to the use of similar dimensionless numbers (such as Reynolds number, Froude number and Peclet number, etc.) to ensure that the flow behavior characteristics between the model and the prototype are similar when designing experimental models in the field of fluid mechanics and engineering. The core of the present embodiment using the similarity principle to design a scaled-down experimental model is to control the proportional relationship of different parameters so that the diffusion process of the gas in the scaled-down test model is similar to the physical process of the actual leakage.

[0099] Since the full-scale gas and power pipeline coupling risk experimental model consumes a great deal of time, manpower and material costs, and the design of a reduced-size gas and power pipeline coupling risk experimental model requires conversion and scaling of various prototype parameters collected at the site in step S1 based on different criteria rather than full proportional scaling, this embodiment is based on the principle of similarity, converts various prototype parameters from aspects such as geometric similarity, Froude number, and Peclet number, characterizes the similarity relationship between the experimental model and the prototype, builds a reduced-size gas and power pipeline coupling risk experimental model, restores the gas leakage and diffusion conditions at the actual gas network and power pipeline site, studies the gas and power pipeline coupling risk conditions, and uses the conclusions of the reduced-size experiment to reflect the leakage and diffusion characteristics of gas in actual scenarios.

[0100] S21. Using geometric similarity as the similarity criterion, the electrical pipeline size, gas pipeline size and coupling spacing are scaled;

[0101] Specifically, the electrical conduit size is scaled using the following formula:

[0102] L m =λL o

[0103] Where, L m represents the electrical conduit size of the experimental model, L o represents the electrical conduit size of the prototype, λ represents the geometric scale factor, and the similarity ratio of the electrical conduit size is λ.

[0104] Use the following formula to scale the gas pipeline size:

[0105] l m =λl o

[0106] In the formula, l m represents the gas pipeline size of the experimental model, l o represents the gas pipeline size of the prototype, and the similarity ratio of the gas pipeline size is λ.

[0107] The coupling spacing is scaled using the following formula:

[0108] d m =λd o

[0109] Where, d m represents the coupling distance of the experimental model, d o represents the coupling spacing of the prototype, and the similarity ratio of the coupling spacing is λ.

[0110] In this embodiment, the similarity criterion of geometric similarity is adopted for the size of the electrical pipeline, the size of the gas pipeline and the coupling spacing. The geometric similarity requires that the shape and proportion of the scaled-down experimental model are consistent with those of the actual site, and the condition of reducing the size in proportion is met.

[0111] S22, using the Froude number as the similarity criterion, scaling the leakage velocity, leakage port area and leakage flow rate;

[0112] The Froude number is a dimensionless number used in fluid mechanics to simulate free surface flow. It is a ratio parameter between inertia force and gravity, indicating the ratio of inertia force to gravity.

[0113] The expression of the Froude number is as follows:

[0114]

[0115] In the formula, F r represents the Froude number, U represents the speed of the object, g represents the acceleration of gravity, and L represents the characteristic length of the object. Since the Froude number itself is a dimensionless number, the speed of the object U and the characteristic length L of the object will be given different physical meanings according to the actual application scenario.

[0116] The force generated by the change in velocity during the flow of the fluid is called the inertial force F. i ; For a fluid moving in a straight line, its inertial force can be simplified to a quantity proportional to the square of the velocity, that is, F i ∝ρ·U 2 ·A, where ρ is the fluid density and A is the fluid action area. The fluid is also affected by gravity F g , gravity can be expressed as F g =ρ·V·g=ρ·L 3 g, where V is the volume of the fluid and L is the characteristic length. i and gravity F g By comparison, we can get the definition of Froude number Since in similar flows, the area A is usually proportional to the square of the characteristic length L (i.e., A∝L 2 ), so the above formula can be simplified to:

[0117] Since the inertial force is proportional to the square of the velocity, and the gravity is proportional to the volume (or the cube of the characteristic length), the proportional relationship between the velocity U and the characteristic length L can be adjusted to make the model and the real object similar in inertial force and gravity.

[0118] S221, using the Froude number as the similarity criterion, the leakage flow rate is scaled;

[0119] In this embodiment, in order to ensure that the scaled-down experimental model and the actual field working conditions maintain consistent fluid behavior under the influence of inertia and gravity, the Froude number of the scaled-down experimental model and the actual field working conditions must be equal, specifically Fr 现场 =Fr 模型 , that is where v o represents the leakage flow rate of the prototype, v m represents the leakage flow rate of the experimental model. According to step S21, L m =λL o The proportional relationship between the leakage flow rate and the leakage rate can be deduced as follows:

[0120] v m =λ 0.5 v o

[0121] In the formula, v m represents the leakage flow rate of the experimental model, v o represents the leakage flow rate of the prototype, and the similarity ratio of the leakage flow rate is λ 0.5 .

[0122] S222, using the Froude number as the similarity criterion, scale the leakage port area;

[0123] In this embodiment, since the area A of the leakage opening is proportional to the square of the characteristic length L, the following formula is used to scale the leakage opening area:

[0124] A m =λ 2 A o

[0125] In the formula, A m Represents the leakage area of ​​the experimental model, A o represents the leakage area of ​​the prototype, and the similarity ratio of the leakage area is λ 2 .

[0126] S223, using the Froude number as a similarity criterion, scaling the leakage flow;

[0127] In this embodiment, the basic formula of the leakage flow Q, Q=A·v, is substituted into the scaling relationship between the leakage port area and the leakage flow rate, and the leakage flow is scaled using the following formula:

[0128] Q m =λ 2.5 Q o

[0129] In the formula, Q m represents the leakage flow of the experimental model, Q o represents the leakage flow of the prototype, and the similarity ratio of the leakage flow is λ 2.5 .

[0130] S23, using the Peclet number as the similarity criterion, the diffusion coefficient is scaled;

[0131] The diffusion process of gas in soil and power channels after leakage is affected by many factors, such as gas concentration gradient, diffusion coefficient, resistance coefficient, soil texture, soil bulk density and soil porosity. Therefore, the study of the diffusion coefficient of gas in different media depends on the properties of the medium and the physical parameters of the gas.

[0132] In this embodiment, the diffusion coefficient of the gas is related to parameters such as temperature and pressure. In the reduced-size experimental model, in order to ensure that the diffusion coefficient is consistent with the actual on-site working conditions, this embodiment keeps the ambient temperature and pressure unscaled, and establishes a similar relationship between the similar experimental model and the actual site through a method based on the dimensionless transformation of the Peclet number.

[0133] The Peclet number is a dimensionless number in fluid mechanics, which refers to the ratio of convective and diffuse mass and heat in a fluid. The expression of the Peclet number is as follows:

[0134]

[0135] Where Pe represents the Peclet number, R e Reynolds number, P r It represents the Prandtl number, V represents the average flow velocity, L represents the characteristic length of the object, and D represents the diffusion coefficient. In other scenarios, it can also be expressed as the thermal diffusivity. Since the Peclet number itself is a dimensionless number, its average flow velocity V, characteristic length L and diffusion coefficient D will be given different physical meanings according to the actual application scenario.

[0136] The Peclet number of the scaled-down experimental model and the actual field conditions must be equal, specifically Pe 现场 =Pe 模型 , that is Where D o represents the diffusion coefficient of the prototype, D m represents the diffusion coefficient of the experimental model. According to step S2, L m =λL o 、v m =λ 0.5 v oThe proportional relationship between the diffusion coefficient and the diffusion coefficient can be deduced as follows:

[0137] D m =λ 1.5 D o

[0138] Where D m represents the diffusion coefficient of the experimental model, D o represents the diffusion coefficient of the prototype, and the similarity ratio of the diffusion coefficient is λ 1.5 .

[0139] In this embodiment, after the geometric scale factor λ (λ is determined according to the size scaling ratio) of the solved reduced-scale experimental model parameters and the prototype parameters is determined, the experimental parameters can be determined for the reduced-scale experiment to ensure that the experimental model and the prototype are similar in flow characteristics, and then the conclusions of the reduced-scale experiment can be used to reflect the leakage and diffusion characteristics of the gas in the actual scenario.

[0140] When exploring the scaled-down experiment of the coupled diffusion process of gas leakage and adjacent power channels, the main purpose of the scaled-down study is to ensure that the experimental model and the actual working conditions have similar behaviors under the same physical conditions, and to obtain a proportional relationship between the scaled-down ratio and λ. Geometric similarity, physical similarity, and similarity of dimensionless numbers will be the basis of the scaling process.

[0141] In this embodiment, the proportional relationship between the scaled-down experimental model parameters and the prototype parameters obtained in step S2 is shown in Table 1 below:

[0142] Table 1 Proportional relationship between scaled-down experimental model parameters and prototype parameters

[0143]

[0144]

[0145] S3. Build a scaled-down experimental model to conduct gas and power pipeline coupling risk experiments;

[0146] Specifically, a reduced-size experimental model is constructed based on the proportional relationship between the reduced-size experimental model parameters and the prototype parameters obtained in step S2, a gas leakage detection module is used to simulate gas pipeline leakage, the gas leakage rate is adjusted, and the coupling distance between the gas and power pipelines is adjusted, a gas leakage and diffusion experiment is performed, and a gas diffusion monitoring module is used to measure and record gas leakage and diffusion conditions;

[0147] S4. Based on the similarity principle, the gas and power pipeline coupling risk experimental data are converted into field data, compared with the theoretical prediction data, and the gas and power pipeline coupling risk experiment is evaluated;

[0148] This embodiment uses similarity theory to convert the model results into prototype scale, non-dimensionalizes the experimental data, analyzes whether the results meet expectations, and predicts the actual situation; by determining the proportional relationship between the scaled-down experimental model parameters and the prototype parameters, it is ensured that the experimental model and the prototype are similar in gas flow characteristics, and then the conclusions of the scaled-down experiment can be used to reflect the leakage and diffusion characteristics of the gas in the actual scene.

[0149] Specifically, this embodiment obtains a relationship diagram between gas leakage concentration and time, and fits and analyzes gas leakage behavior characteristics under different gas leakage rates and different coupling intervals, so as to provide a reference for safety monitoring and risk assessment of gas pipeline leakage.

[0150] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A gas and power pipeline coupling simulation device based on reduced size, characterized in that: Including soil environment module, power channel module, gas leakage detection module and gas diffusion detection module; The soil environment module comprises a soil box, wherein the soil box is filled with soil; The power conduit module comprises a cable trench, a ventilation duct, an infiltration port and a control switch; the power conduit module is arranged in a soil box, ventilation ducts are arranged at both ends of the cable trench, the vents of the ventilation ducts are located on the soil surface, a plurality of infiltration ports are arranged on different sides of the cable trench, and the control switch is arranged on the infiltration port; The gas leakage detection module comprises a gas pipeline, a high-pressure gas storage tank, a pressure regulating valve, a flow meter, a main pipe ball valve, a branch pipe ball valve and a leakage nozzle; the high-pressure gas storage tank, the pressure regulating valve, the flow meter and the main pipe ball valve are connected in sequence through the gas pipeline, the output end of the main pipe ball valve is respectively connected to the input ends of the plurality of branch pipe ball valves, the output end of the branch pipe ball valve is connected to the input end of the leakage nozzle, the branch pipe ball valve and the leakage nozzle are arranged in a soil box, the output end of the leakage nozzle serves as a leakage port, the plurality of leakage nozzles are respectively arranged on different sides of the cable trench, and the coupling spacing between the gas pipeline and the cable trench is controlled by adjusting the length of the leakage nozzle; The gas diffusion detection module includes a gas detection concentration sensor, a data acquisition unit and a computer; the gas detection concentration sensor is arranged at the infiltration entrance of the power pipeline module, the input end of the data acquisition unit is respectively connected to the output ends of multiple gas detection concentration sensors, and the output end of the data acquisition unit is connected to the computer.

2. The gas and power pipeline coupling simulation device based on reduced size according to claim 1 is characterized in that: The soil is sandy soil, clay or loam, and the soil box has a length of 5 m, a width of 3 m and a height of 1.2 m.

3. The gas and power pipeline coupling simulation device based on reduced size according to claim 1 is characterized in that: The cable trench is a rectangular stainless steel pipe with a length of 3m, a width of 0.3m and a height of 0.3m.

4. The gas and power pipeline coupling simulation device based on reduced size according to claim 1 is characterized in that: The coupling mode of the cable trench and the gas pipeline is parallel coupling or cross coupling, and the coupling distance between the cable trench and the gas pipeline is adjustable.

5. The gas and power pipeline coupling simulation device based on reduced size according to claim 4 is characterized in that: The length of the leakage nozzle is adjustable, and the coupling distance between the cable trench and the gas pipeline can be adjusted by changing the length of the leakage nozzle.

6. The gas and power pipeline coupling simulation device based on reduced size according to claim 1 is characterized in that: The diameter of the gas pipeline is 20 mm, and the diameter of the leakage nozzle is any one of 20 mm, 32 mm and 40 mm.

7. The method for simulating gas and power pipeline coupling based on reduced size according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Collect prototype parameters of the actual gas pipeline network and power pipeline site; the prototype parameters include geometric dimensions, leakage source parameters, environmental parameters and critical space state; the geometric dimensions include electrical pipeline dimensions, gas pipeline dimensions and coupling spacing; the leakage source parameters include leakage port area, leakage flow rate, leakage flow rate and diffusion coefficient; the environmental parameters include wind speed, temperature and pressure; the critical space state includes soil characteristics and relative position; S2, scaling the prototype parameters to the scaled-down experimental model parameters based on similarity theory design; S21. Using geometric similarity as the similarity criterion, the electrical pipeline size, gas pipeline size and coupling spacing are scaled; S22, using the Froude number as the similarity criterion, scaling the leakage velocity, leakage port area and leakage flow rate; S23, using the Peclet number as the similarity criterion, the diffusion coefficient is scaled; S3. Build a scaled-down experimental model to conduct a gas and power pipeline coupling risk experiment; S4. Based on the similarity principle, the gas and power pipeline coupling risk experimental data are converted into field data, compared with the theoretical prediction data, and the gas and power pipeline coupling risk experiment is evaluated.

8. The method for simulating gas and power pipeline coupling based on reduced size according to claim 7, characterized in that: In step S21, the electrical pipeline size, gas pipeline size and coupling spacing are scaled based on geometric similarity as the similarity criterion as follows: Use the following formula to scale electrical conduit sizes: L m =λL o Where, L m represents the electrical conduit size of the experimental model, L o represents the electrical conduit size of the prototype, λ represents the geometric scale factor, and the similarity ratio of the electrical conduit size is λ; Use the following formula to scale the gas pipeline size: the m =λl o In the formula, l m represents the gas pipeline size of the experimental model, l o represents the gas pipeline size of the prototype, and the similarity ratio of the gas pipeline size is λ; The coupling spacing is scaled using the following formula: d m =λd o Where, d m represents the coupling distance of the experimental model, d o represents the coupling spacing of the prototype, and the similarity ratio of the coupling spacing is λ.

9. The method for simulating gas and power pipeline coupling based on reduced size according to claim 8, characterized in that: In step S22, the leakage velocity, leakage port area and leakage flow rate are scaled using the Froude number as the similarity criterion as follows: The leakage flow rate is scaled using the following formula: v m =λ 0.5 v o In the formula, v m represents the leakage flow rate of the experimental model, v o represents the leakage flow rate of the prototype, and the similarity ratio of the leakage flow rate is λ 0.5 ; The leak area is scaled using the following formula: A m =λ 2 A o In the formula, A m Represents the leakage area of ​​the experimental model, A o represents the leakage area of ​​the prototype, and the similarity ratio of the leakage area is λ 2 ; The leakage flow is scaled using the following formula: Q m =λQ o In the formula, Q m represents the leakage flow of the experimental model, Q o represents the leakage flow of the prototype, and the similarity ratio of the leakage flow is λ 2.5 .

10. The method for simulating gas and power pipeline coupling based on reduced size according to claim 9, characterized in that: In step S23, the diffusion coefficient is scaled using the Peclet number as the similarity criterion as follows: The diffusion coefficient is scaled using the following formula: D m =λ 1.5 D o Where D m represents the diffusion coefficient of the experimental model, D o represents the diffusion coefficient of the prototype, and the similarity ratio of the diffusion coefficient is λ 1.5 .

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