Optimization method, equipment and medium of building siphon drainage network based on CFD and Modelica

Abstract

The present invention discloses a method, device, and medium for optimizing a building siphonic drainage network based on CFD and Modelica. The method comprises the following steps: 1) establishing a BIM model of the complete building siphonic drainage network; 2) extracting the geometric model and hydraulic calculation parameter attributes of the roof drains and siphonic rainwater buckets in the BIM model, determining the calculation range and calculation boundary conditions, and establishing a three-dimensional computational fluid dynamics analysis CFD model; 3) optimizing the layout of the rainwater buckets; 4) extracting the IFC attribute data of the BIM pipe network to establish a Modelica pipe system simulation model; 5) performing simulation calculations on the pipe system based on the Modelica pipe system simulation model, and optimizing any unreasonable pipe design aspects based on the pipe system's operational status; 6) establishing a CFD simulation model of the energy dissipation well and a joint simulation model based on the pipe network's FMI data; and 7) verifying the energy dissipation effect of the siphonic energy dissipation well. The method can provide comprehensive review and prediction for the siphonic system during the building design, construction, and operation and maintenance stages.

Description

Technical Field

[0001] The present invention relates to a building water supply and drainage design technology, and in particular to a building siphon drainage network optimization method, equipment and medium based on CFD and Modelica. Background Art

[0002] The roof structures of modern public space buildings, such as airport terminals, high-speed rail stations, and stadiums, often feature large spans and complex spatial shapes, placing higher demands on the design of roof drainage systems. Siphonic drainage systems are widely used in large-space, large-span, and large-capacity buildings due to their excellent drainage performance, large drainage capacity, and flexible suspension pipe layout. However, existing drainage design methods for siphonic systems use a one-dimensional hydraulic calculation review of multiple siphonic hoppers based on the ideal full-pipe flow assumption, failing to fully consider the runoff flow, actual siphon initiation, and formation conditions of different roof types. While three-dimensional computational fluid dynamics (CFD) technology is more accurate for analyzing the siphonic drainage process, it is difficult to apply to global pipe network hydraulic calculations due to computational efficiency issues. Fully considering the drainage performance of siphonic drainage systems during operation during the design phase is crucial for achieving efficient roof drainage and safe roof performance.

[0003] As building information modeling (BIM) technologies continue to mature, three-dimensional design and construction of water supply and drainage systems during the preliminary and detailed design phases have gradually become widely used in engineering projects. By directly performing siphonic drainage system selection calculations and global pipe network hydraulic calculations based on BIM models during the design phase, performance-based siphonic drainage design and global pipe network optimization can be achieved. This fully considers the drainage performance of specific roof forms and actual drainage pipe network solutions during the actual operational phase, thereby achieving performance-based design of siphonic drainage systems. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a building siphon drainage network optimization method, equipment and medium based on CFD and Modelica in response to the defects in the existing technology.

[0005] The technical solution adopted by the present invention to solve the technical problem is: a building siphon drainage network optimization method based on CFD and Modelica, comprising the following steps:

[0006] 1) Based on the preliminary design of the building roof and siphonic rainwater drainage system, a BIM model of the complete building siphonic drainage network was established. The BIM model included roof drains, siphonic rainwater hoppers, pipe networks (tail pipes, suspended pipes), and energy dissipation wells.

[0007] 2) Extract the geometric model and hydraulic calculation parameter attributes of the roof drain ditch and siphon rainwater bucket in the BIM model, determine the calculation scope and calculation boundary conditions, and establish a three-dimensional computational fluid dynamics analysis CFD model; obtain the transient siphon startup status and the water flow state of the connecting pipe;

[0008] 3) Analyze the siphon formation conditions and discharge flow time history curve of each rainwater bucket, evaluate the drainage conditions of different rainwater bucket tail pipes and the rationality of rainwater bucket flow distribution, and optimize the layout of rainwater buckets;

[0009] 4) Extracting IFC property (IfcPropertyDefinition, attributes associated with entities) data from the BIM pipe network to establish a Modelica piping system simulation model. Accuracy verification of piping components was performed before calculations, and the instantaneous flow rate data of the siphon system connecting pipes calculated in 3) was used as boundary conditions.

[0010] 5) Simulate the piping system based on the Modelica piping system simulation model to obtain the real-time working status of the piping system; optimize the unreasonable piping design according to the operation of the piping system;

[0011] 6) Provide the BIM geometric model and IFC attributes of the energy dissipation well, establish a CFD simulation model of the energy dissipation well, and establish a joint simulation model based on the pipeline network FMI data.

[0012] 7) Based on the FMI "pipeline network-energy dissipation well" joint simulation model, calculations are performed to verify whether the siphon energy dissipation well can achieve the designed energy dissipation effect.

[0013] According to the above scheme, the step 1) includes the following steps:

[0014] 1.1) Based on engineering experience and specifications, preliminary design of the siphon drainage system is carried out according to the building roof form and requirements:

[0015] First, divide the catchment area based on the shape and slope of the building roof. Next, determine the design drainage flow rate for the area based on the area of the catchment area and local hydrological and meteorological data and specifications. Then, design the size of the roof gutter based on the design drainage flow rate and the slope of the catchment area, and determine the placement of the siphonic rainwater bucket. Next, determine the design inlet flow rate of the siphonic rainwater bucket based on the design flow rate, and determine the pipe diameter based on the design flow rate of each pipe. Finally, select the type of canister based on the design flow rate of the drainage pipe.

[0016] 1.2) Based on the preliminary design of the siphonic rainwater drainage system, a 3D BIM model of the roof drains, rainwater troughs, siphon pipes, siphon energy dissipation wells, and part of the municipal pipe network was established;

[0017] Create a 3D model of each gutter based on its model. A siphonic gutter typically consists of a fairing, a waterproof pressure ring, a hopper seat, and a steel-plastic connector. The waterproof pressure ring and hopper seat adhere tightly to the gutter floor, so they don't need to be modeled separately during the numerical calculation. The steel-plastic connector, connected to the connecting pipe, forms part of the piping system and also doesn't need to be modeled separately. Therefore, modeling for the siphonic gutter primarily focuses on the fairing, creating a 3D BIM model of the fairing using modeling software.

[0018] According to the above scheme, the step 2) includes the following steps:

[0019] 2.1) Based on the building water supply and drainage BIM model, a 3D model of the roof drainage and siphonic rainwater bucket was extracted. A 3D fluid calculation model of the "drainage ditch-rainwater bucket-connecting pipe" was established. The inner wall of the pipe was extracted from the 3D BIM model to establish the fluid calculation domain, and the 3D model of the siphonic rainwater bucket was adjusted to the corresponding position.

[0020] 2.2) Based on the water catchment area division of the building roof and the historical meteorological data and regulatory information of the area, the local rainfall duration curve is determined and used as the boundary condition for the three-dimensional numerical simulation;

[0021] The calculation scope includes the direction of roof rainwater runoff, gutter rainwater flow characteristics, and the drainage conditions of rainwater hoppers;

[0022] 2.3) Dynamically simulate the process of rainwater flowing from the gutter through the rain gutter into the connecting pipe. Based on the CFD method, analyze the instantaneous change curve of the gutter liquid level and the flow pattern changes of the flow into the rain gutter.

[0023] According to the above solution, in step 3), optimizing the rain gutter layout position includes the following steps:

[0024] 3.1) Analyze the water level changes in the drainage ditch to obtain the maximum flooding depth that can be achieved during the rainfall, and assess whether the flooding depth poses a threat to the structural safety;

[0025] 3.2) Determine the flow distribution of each siphon system hopper based on the flooding status of the siphon hopper and the flow time history curve at the end of the connecting pipe. Study whether the siphon hopper is overloaded or inefficient in drainage, and optimize its layout.

[0026] 3.3) When multiple siphon systems share a gutter, study the working conditions of each siphon system and optimize the layout to prevent the siphon system from being in a high-load state and forming a large negative pressure, which may damage the pipeline safety;

[0027] 3.4) Study the operation of the siphon system in extreme cases where a siphon pipe is blocked or the siphon rainwater bucket is damaged, and optimize the layout.

[0028] According to the above scheme, step 4) is specifically as follows:

[0029] 4.1) Establish a system simulation model library (commercial library) in Modelica-based system simulation software, generally including pipelines, elbows, tees, reducers, inlets, outlets, etc., and verify the model accuracy using standard pipelines;

[0030] 4.2) Extract the IFC attributes of the siphon pipe network based on the building water supply and drainage BIM model. The IFC attributes include pipe diameter, material, location information, and geometry information. Build a Modelica piping system simulation model.

[0031] 4.3) Based on the calculation results of step 3), the flow time history curve at the end of the connecting pipe is used as the inlet boundary condition of the system simulation model.

[0032] According to the above scheme, step 6) is specifically as follows:

[0033] 6.1) Establish a 3D BIM model of the siphon energy dissipation well flow field based on the building water supply and drainage BIM model;

[0034] 6.2) Obtain the siphon network FMI data based on the calculation results of step 5) and import it into the calculation model of the siphon energy dissipation well.

[0035] FMI (Functional Mock-up Interface) is an open source standard interface for co-simulation, which is used to achieve one-way data transmission between system simulation and CFD simulation in this step.

[0036] According to the above scheme, step 7) checks whether the siphon energy dissipation well can achieve the designed energy dissipation effect, specifically:

[0037] 7.1) Based on the study of the water flow rate flowing into and out of the siphon energy dissipation well, analyze whether its energy dissipation effect meets the requirements;

[0038] 7.2) Based on the CFD numerical simulation results of gas-liquid two-phase flow, analyze whether the energy dissipation well cover is at risk of being "lifted up" and causing a "well flip" phenomenon;

[0039] 7.3) Based on the CFD numerical simulation results of gas-liquid two-phase flow, study the extreme water level in the cavity of the energy dissipation well under the most unfavorable conditions and investigate whether the siphon energy dissipation well can be "filled up";

[0040] 7.4) Based on the CFD numerical simulation results of gas-liquid two-phase flow, study whether the municipal pipeline meets the size of the instantaneous discharge volume.

[0041] The present application also provides an electronic device, comprising: one or more processors; and a memory for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors execute the above method.

[0042] The present application also provides a computer-readable storage medium having executable instructions stored thereon, which, when executed by a processor, causes the processor to execute the above method.

[0043] The present application also provides a computer program product, including a computer program, which implements the above method when executed by a processor.

[0044] The beneficial effects produced by the present invention are:

[0045] This paper provides a building siphon network optimization analysis method based on joint CFD and Modelica system simulation. This method provides comprehensive verification and prediction of siphon systems during the building design, construction, and operation and maintenance phases. It addresses the issue of rainfall duration, which is often overlooked in traditional design based on specifications and experience, and effectively predicts and addresses disasters caused by instantaneous rainfall accumulation. Furthermore, while maintaining a certain level of accuracy, it minimizes computational costs and time, making it more suitable for large-scale adoption.

[0046] Based on the BIM / PLM information platform, this paper provides a collaborative, digital solution for the dynamic analysis of siphonic drainage on large-span roofs, leveraging the advantages of BIM model performance analysis. The drainage facility verification calculation method proposed based on this calculation process can provide a reference for siphonic drainage systems in the architectural proposal and preliminary design stages, especially for large-span roof structures with complex curved surfaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0048] Figure 1 is a flow chart of a method according to an embodiment of the present invention;

[0049] Figure 2 Schematic diagram of the structure of the siphon rainwater drainage system in an embodiment of the present invention;

[0050] In the figure: 1- siphon rainwater bucket; 2- connecting pipe; 3- suspension pipe; 4- riser; 5- discharge pipe; 6- siphon rainwater energy dissipation well; 7- municipal pipe network 7. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0052] like Figure 1 As shown in the figure, a building siphon network optimization analysis method based on CFD and Modelica system joint simulation is shown. Taking the siphon rainwater energy dissipation system of an airport terminal as an example, the specific steps of the embodiment of the present invention are as follows:

[0053] 1) Design the roof water catchment area according to the building type and usage function, and preliminarily design the drainage system based on local hydrological and meteorological data. According to the preliminary design plan of the building roof and siphonic rainwater drainage system, establish a BIM detailed model of the complete pipe network system including roof drainage ditch, siphonic rainwater bucket, pipe network (tail pipe, suspension pipe) and energy dissipation well; Figure 2 As shown;

[0054] 1.1) Drainage areas are divided according to the roof shape of the terminal building. The roof of a certain area of an airport terminal is divided into four drainage areas based on the roof slope and shape, and are distinguished by different colors.

[0055] In this example, catchment area 4 is used as an example. Rainwater flows through the roof into a "]"-shaped gutter. The roof slope in catchment area 4 is 3%, and the roof tiles provide a diversion effect. Within the "]"-shaped gutter, there are two independent siphonic rainwater energy dissipation systems, each with four siphonic rainwater hoppers. In this example, the "┓"-shaped siphonic rainwater energy dissipation system is used as the research object.

[0056] The design rainfall and the design flow rate of each rain gutter were determined based on engineering experience and specifications. The design drainage capacity was 89.6 L / s, averaging 44.8 L / s per system and 11.2 L / s per gutter. Siphonic rainwater energy dissipation wells were designed based on the design flow rate of the discharge pipes.

[0057] 1.2) Based on the preliminary design of the siphon system, a 3D model of the siphon piping system was created using Dassault Systèmes' 3DEXPERIENCE platform. A 3D BIM model of the drainage ditch, rainwater bucket, connecting pipe, suspension pipe, riser, discharge pipe, energy dissipation well, and municipal pipe (partial) was created using CATIA software.

[0058] 2) Extract the geometric model and hydraulic calculation parameter attributes of the roof drain ditch and siphon rainwater bucket in the BIM model, determine the calculation scope and calculation boundary conditions, and establish a three-dimensional computational fluid dynamics analysis model;

[0059] Dynamically simulate the process of rainwater flowing from the drainage ditch through the rain gutter into the connecting pipe, and analyze the instantaneous change curve of the gutter liquid level and the flow state changes of the flow into the rain gutter.

[0060] 2.1) Based on the CATIA electromechanical model on the 3DEXPERIENCE platform, the computational domain of the fluid and the 3D model of the siphon rainwater bucket were extracted and exported to the computational fluid dynamics software XFlow.

[0061] 2.2) Based on the establishment of the catchment area of the building roof and the historical meteorological data and regulatory information of the area, the boundary conditions of the three-dimensional numerical simulation are determined, and the lattice Boltzmann method (LBM) is used for calculation.

[0062] The required rainfall duration is selected according to the specification DB4201 / T 641-2020 "Wuhan City Rainstorm Intensity Formula and Design Rainstorm Type". According to the specification, the central urban area of Wuhan adopts a unified rainstorm intensity formula. The rainstorm intensity formula uses the annual maximum value method:

[0063]

[0064] Where: i: represents the design rainstorm intensity (mm / min); P: recurrence period (a); t: rainfall duration (min);

[0065] 2.3) In this embodiment, taking a return period of 50 years as an example, the expression is:

[0066]

[0067] From the rainfall history chart, it can be seen that the rainfall generated in the first few minutes of the rainstorm is much greater than that in the subsequent moments. Therefore, under the traditional design standard of average rainfall intensity, there is actually a risk of water accumulation.

[0068] The rainfall duration curve was imported into the XFlow calculation software with 1-min intervals as coordinate points as the initial calculation conditions for numerical simulation.

[0069] 2.4) XFlow software uses the meshless Lattice Boltzmann method to calculate the "roof-gutter-rainwater gutter" system. The Lattice Boltzmann Method (LBM) is a development of the Lattice Gas Automata (LGA) method. Its main feature is that it replaces the Boolean variables in the LGA method with a single-particle distribution function. It also uses the Boltzmann transport equation to solve some problems encountered in the Navier-Stokes equations and the LGA. The Boltzmann transport equation is defined as follows:

[0070]

[0071] Among them, f i represents the distribution function at position i, Denotes its corresponding collision operator. Based on this equation, the compressible NS equations can be solved through the Chanpman-Enskog expansion [9]. The definition of the collision operator is as follows:

[0072]

[0073] in, is the local equilibrium constant, and τ is the characteristic relaxation time (related to the macroscopic viscosity).

[0074] In XFlow software, set the calculation model to Multiphase, the gutter inlet to the flow inlet, the end of the connecting pipe and the top of the gutter to the pressure outlet. Set all other locations to wall conditions and set the flow monitoring position.

[0075] It should be noted that when using CFD to calculate roof runoff, gutters, and flow fields near rain gutters, the meshless XFlow software, based on the lattice Boltzmann method, is typically used, but this is not limited to XFlow. Any CFD-based software that solves the Navier-Stokes equations and their variants is also applicable, such as XFlow, OpenFoam, Fluent, Star CCM+, and Flow 3D.

[0076] 3) Performance evaluation and parameter optimization of siphon drainage for multiple rainwater hoppers. Specifically analyze the siphon formation conditions and discharge flow time history curves for each rainwater hopper, evaluate the drainage conditions of different rainwater hopper tail pipes and the rationality of rainwater hopper flow distribution, and optimize the placement of rainwater hoppers.

[0077] 3.1) In the XFlow software, several 1cm wide elongated planes were inserted as water level monitoring points to study the water level variation characteristics of the roof gutter. By integrating the "Phase" of these planes, the water level per unit width was obtained. By analyzing the water level variation characteristics within the gutter, the maximum inundation depth that could be achieved during a rainfall event was determined, and whether this inundation depth poses a threat to structural safety was assessed. In this example, the inundation height met the requirements and did not require modification.

[0078] 3.2) Determine the flow distribution of each siphon system hopper based on the flooding status of the siphon hopper and the flow time-history curve at the end of the connecting pipe, and study whether some siphon hoppers are overloaded and some are in an inefficient drainage state.

[0079] 3.3) If the simulation results for the "gutter-rainwater gutter-connecting pipe" system indicate an unreasonable design, redesign it. For typical issues such as gutter size, gutter spacing, and the distance between the roof and the gutter, identify and investigate unreasonable gutter designs.

[0080] 4) The BIM pipe network IFC attribute data is used to establish a Modelica piping system simulation model. The accuracy of the piping components is verified before calculation, and the instantaneous flow data of the siphon system connecting pipe calculated in 3) is used as the boundary condition.

[0081] 4.1) Before calculation, verify the CATIAPiping library in Dymola software, build a simple system simulation model, and verify the calculation accuracy of components such as pipes, tees, and reducers.

[0082] 4.2) Generate a Dymola system simulation model based on the CATIAPiping library directly based on the Behavior Modeling application of the 3DEXPERIENCE platform. The system simulation software Dymola has the characteristics of fast calculation speed and high accuracy in calculating long and thin pipes of a single medium. Based on the "CATIAPiping" library, establish a system simulation model of "connecting pipe 2-suspension pipe 3-riser 4-connecting pipe 5". The system simulation model is built with reference to the actual case of this embodiment, and consists of four flow inlet branches and one pressure outlet trunk. The flow inlet can use the instantaneous flow data obtained by CFD simulation as the inlet condition, or it can be used as a hydraulic check based on the design flow.

[0083] 4.2) Export the flow rate time history curves at the end of the discharge pipe calculated in 3) to a .txt file. There are four rain gutter flow time history curves. Use these four flow rate time history curves as the inlet boundary conditions for the system simulation model. The inlet condition of the system simulation model is set as the flow inlet, and the end of the discharge pipe is set as the pressure outlet. In this case, the pipe wall roughness is 0.55 mm.

[0084] It should be noted that when performing hydraulic calculations on pure piping systems based on system simulation models, Dymola software and the "CATIA Piping Library" are typically used, but are not limited to Dymola. Any software based on the Modelica language for modeling and analysis is applicable.

[0085] 5) Simulate the piping system based on the Modelica piping system simulation model to obtain the real-time working status of the piping system. Optimize any unreasonable piping design based on the piping system's operating conditions.

[0086] 5.1) Analyze the numerical results of the system simulation. If the design is unreasonable, adjust the model and recalculate. If the pipeline design is reasonable, derive the flow time history curve at the end of the discharge pipe as the initial boundary condition for subsequent calculations.

[0087] 5.2) Through the system simulation at this stage, the drainage velocity and pressure characteristics of rainwater at the end of connecting pipe 5 can be quickly obtained. For general engineering problems, the calculation time of this model only takes a few seconds, greatly improving the efficiency of engineers.

[0088] 6) Provide the BIM geometric model and IFC attributes of the energy dissipation well, establish a CFD simulation model of the energy dissipation well, and establish a joint simulation model based on the pipeline network FMI data.

[0089] 6.1) Based on the CATIA electromechanical model on the 3DEXPERIENCE platform, the 3D models of the siphon rainwater energy dissipation well were extracted and exported to the XFlow software.

[0090] 6.2) Import the FMI data calculated in 5) into the Xflow software and set the boundary conditions.

[0091] 6.3) It should be noted that when calculating the gas-liquid interaction in energy dissipation wells using CFD methods, the gridless Xflow software, based on the lattice Boltzmann method, is typically used, but this is not limited to Xflow. Any CFD-based software that solves the Navier-Stokes equations and their variants is also applicable, such as Xflow, OpenFoam, Fluent, StarCCM+, and Flow 3D.

[0092] 7) Perform calculations based on the FMI "pipeline network-energy dissipation well" co-simulation model to verify whether the siphon energy dissipation well can achieve the designed energy dissipation effect. Based on the 3D CFD numerical calculation results of the siphon energy dissipation well, evaluate whether it meets the energy dissipation effect. If necessary, modify the energy dissipation well size and energy dissipation baffle type.

[0093] 7.1) After obtaining the discharge velocity from discharge pipe 5 based on the system simulation model, the water particles are at high speed and high pressure. Directly discharging the water into the municipal pipe network would cause significant damage to the municipal pipes. An energy dissipation well 6 is typically installed between the end of discharge pipe 5 and the municipal pipe network 7 to mitigate this potential damage.

[0094] 7.2) Since the water discharged from the siphon discharge pipe 5 is in a high-pressure and high-speed state, it will mix and splash with the air after entering the energy dissipation well, and the water will show a strong nonlinear state. At this time, the analysis method based on theory and full pipe flow is not suitable. Through the CFD method, the results calculated by the system simulation model are imported into the inlet boundary of the CFD model, and the flow field inside the cavity of the energy dissipation well 5 is numerically simulated. The right inlet is composed of discharge pipes of different siphon rainwater energy dissipation systems. Different discharge pipes have different pipe diameters and flow time series, and the right side is discharged from the municipal pipeline network. It can be seen that the high-speed water body is transformed into a low-speed water body after impacting the energy dissipation well baffle. At this time, if the discharge speed and pressure of the discharge pipe are monitored, the impact of the siphon system on the municipal pipeline network can be evaluated.

[0095] The flow velocity distribution of the siphon energy dissipation well connected to the municipal pipeline is studied to prevent excessive flow from damaging the municipal pipeline network. Based on the 3D CFD numerical calculation results of the siphon energy dissipation well, the energy dissipation effect is evaluated. If necessary, the energy dissipation well size and energy dissipation baffle type can be modified.

[0096] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all such improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A building siphon drainage network optimization method based on CFD and Modelica, characterized by: The following steps are involved: 1) Based on the preliminary design of the building roof and siphonic rainwater drainage system, a BIM model of the complete building siphonic drainage network was established. The BIM model included roof drains, siphonic rainwater hoppers, pipe networks, and energy dissipation wells. 2) Extract the geometric model and hydraulic calculation parameter attributes of the roof drain ditch and siphon rainwater bucket in the BIM model, determine the calculation scope and calculation boundary conditions, and establish a three-dimensional computational fluid dynamics analysis CFD model; obtain the transient siphon startup status and the water flow state of the connecting pipe; 3) Analyze the siphon formation conditions and discharge flow time history curve of each rainwater bucket, evaluate the drainage conditions of different rainwater bucket tail pipes and the rationality of rainwater bucket flow distribution, and optimize the layout of rainwater buckets; 4) Extract the BIM pipe network IFC attribute data to establish a Modelica pipe system simulation model. Verify the accuracy of the pipe components before calculation. Use the instantaneous flow data of the siphon system connecting pipe obtained from the calculation results in step 3) as the boundary condition. 5) Simulate the piping system based on the Modelica piping system simulation model to obtain the real-time working status of the piping system; optimize the unreasonable piping design according to the operation of the piping system; 6) Produce the BIM geometry model and IFC attributes of the energy dissipation well, establish a CFD simulation model of the energy dissipation well, and establish a joint simulation model based on the pipe network FMI data; The step 6) is specifically as follows: 6.1) Establish a 3D BIM model of the siphon energy dissipation well flow field based on the building water supply and drainage BIM model; 6.2) Obtain the siphon network FMI data based on the calculation results of step 5) and import it into the calculation model of the siphon energy dissipation well, and set boundary conditions; 7) Perform calculations based on the FMI "pipeline network-energy dissipation well" joint simulation model to verify whether the siphon energy dissipation well can achieve the designed energy dissipation effect; 7.1) Based on the study of the water flow rate flowing into and out of the siphon energy dissipation well, analyze whether its energy dissipation effect meets the requirements; By using CFD method, the results of the system simulation model calculation are imported into the inlet boundary of the CFD model to perform numerical simulation of the flow field inside the energy dissipation well cavity. 7.2) Based on the CFD numerical simulation results of gas-liquid two-phase flow, analyze whether the energy dissipation well cover is at risk of being "lifted up" and causing a "well flip" phenomenon; 7.3) Based on the CFD numerical simulation results of gas-liquid two-phase flow, study the extreme water level in the cavity of the energy dissipation well under the most unfavorable conditions and investigate whether the siphon energy dissipation well can be "filled"; 7.4) Based on the CFD numerical simulation results of gas-liquid two-phase flow, study whether the municipal pipeline meets the size of the instantaneous discharge volume.

2. The building siphon drainage network optimization method based on CFD and Modelica according to claim 1 is characterized in that: The step 1) comprises the following steps: 1.1) Based on engineering experience and specifications, preliminary design of the siphon drainage system is carried out according to the building roof form and requirements: First, divide the catchment area based on the shape and slope of the building roof. Next, determine the design drainage flow rate for the area based on the area of the catchment area and local hydrological and meteorological data and specifications. Then, design the roof gutter size based on the design drainage flow rate and the slope of the catchment area, and determine the placement of the siphonic rainwater bucket. Next, determine the design inlet flow rate of the siphonic rainwater bucket based on the design flow rate, and determine the pipe diameter based on the design flow rate of each pipe. Finally, select the type of canister based on the design flow rate of the drainage pipe. 1.2) Based on the preliminary design of the siphonic rainwater drainage system, a 3D BIM model of the roof gutters, rainwater troughs, siphon pipes, siphon energy dissipation wells, and part of the municipal pipe network was established.

3. The method for optimizing a building siphon drainage network based on CFD and Modelica according to claim 2, wherein the step 2) comprises the following steps: 2.1) Based on the building water supply and drainage BIM model, a 3D model of the roof drainage and siphonic rainwater bucket was extracted. A 3D fluid calculation model of the "drainage ditch-rainwater bucket-connecting pipe" was established. The inner wall of the pipe was extracted from the 3D BIM model to establish the fluid calculation domain, and the 3D model of the siphonic rainwater bucket was adjusted to the corresponding position. 2.2) Based on the water catchment area division of the building roof and the historical meteorological data and regulatory information of the area, the local rainfall duration curve is determined and used as the boundary condition for the three-dimensional numerical simulation; 2.3) Dynamically simulate the process of rainwater flowing from the gutter through the rain gutter into the connecting pipe. Based on the CFD method, analyze the instantaneous change curve of the gutter liquid level and the flow pattern changes of the flow into the rain gutter.

4. The CFD and Modelica-based building siphon drainage network optimization method according to claim 3, wherein in step 3), optimizing the rain gutter layout position comprises the following steps: 3.1) Analyze the water level changes in the drainage ditch to obtain the maximum flooding depth that can be achieved during the rainfall, and assess whether the flooding depth poses a threat to the structural safety; 3.2) Determine the flow distribution of each siphon system hopper based on the flooding status of the siphon hopper and the flow time history curve at the end of the connecting pipe. Study whether the siphon hopper is overloaded or inefficient in drainage, and optimize its layout. 3.3) When multiple siphon systems share a gutter, study the working conditions of each siphon system and optimize the layout to prevent the siphon system from being in a high-load state and forming a large negative pressure, which may damage the pipeline safety; 3.4) Study the operation of the siphon system in extreme cases where a siphon pipe is blocked or the siphon rainwater bucket is damaged, and optimize the layout.

5. The building siphon drainage network optimization method based on CFD and Modelica according to claim 1, wherein the step 4) is specifically: 4.1) Establish a system simulation model library in Modelica-based system simulation software and verify the model accuracy through standard pipelines; 4.2) Extract the IFC attributes of the siphon pipe network based on the building water supply and drainage BIM model. The IFC attributes include pipe diameter, material, location information, and geometry information. Build a Modelica piping system simulation model. 4.3) Based on the calculation results of step 3), the flow time history curve at the end of the connecting pipe is used as the inlet boundary condition of the system simulation model.

6. An electronic device, characterized in that: include: one or more processors; as well as a storage device for storing one or more programs, When the one or more programs are executed by the one or more processors, the one or more processors are enabled to perform the method according to any one of claims 1 to 5.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 5 is implemented.

Images