Disconnection energy dissipation facility of building siphon rainwater system for sponge city

Abstract

The application discloses a disconnecting energy dissipation facility of a building siphon rainwater system for a sponge city, which comprises an energy dissipation box body (1), water inlet pipes (2) and water outlet pipes (5) are alternately connected to the upper and lower sides of the left and right side walls of the energy dissipation box body (1), the water inlet pipes (2) extend into the lower bottom of the energy dissipation box body (1) and are divided into a slanting tee joint, a pipeline extending straight along the water inlet pipes (2) is a shunt pipe (3), a pipeline extending upward and obliquely from the water inlet pipes (2) is an inner chamber main pipe (4), the upper end of the inner chamber main pipe (4) is connected to the water outlet pipes (6), and the side wall of the energy dissipation box body (1) is provided with a side wall water outlet (6). The technical effect of the application is that the energy of high-energy siphon rainwater is reduced, the water outlet of the siphon rainwater system can be safely discharged to outdoor sponge facilities, a large amount of inflow rainwater under high flow can be discharged, and the problems of geyser caused by water stagnation in the facility and loss of energy dissipation function caused by rainwater filling the whole box are avoided.

Description

Technical Field

[0001] This invention belongs to the field of rainwater drainage technology, specifically relating to an energy dissipation facility that enables siphon drainage systems to disconnect rainwater in the context of sponge city construction. It enables high-velocity, high-flow-rate fluids in siphon rainwater drainage systems to dissipate energy, reduce velocity, and discharge to the surface, further improving the utilization rate of sponge facilities for building rainwater. Background Technology

[0002] The literature "A Study on the Effect of Rainwater Disconnection on Urban Stormwater Control," by Gong Yongwei et al., *Water Supply and Drainage*, Vol. 40, No. 1, 2014, p. 135, defines "rainwater disconnection" as follows: The concept of rainwater disconnection can be divided into narrow and broad senses. In a narrow sense, rainwater disconnection refers to the disconnection of downpipes, that is, changing the path of roof rainwater runoff and directing it to permeable areas around the building or rainwater collection facilities (such as rainwater bins). In a broad sense, rainwater disconnection not only includes simple downpipe disconnection but also includes the use of Low Impact Development (LID) measures such as green roofs, permeable paving, and bioretention to regulate rainwater. Green roofs, through the interception effect of the vegetation layer and the water storage effect of the substrate layer, retain or store roof runoff that would otherwise be directly discharged into the pipe system, delaying the time of runoff generation and reducing the amount of runoff discharged.

[0003] Siphonic rainwater drainage systems can quickly and promptly discharge rainwater outdoors to reduce roof safety hazards. However, if the downpipes of a siphonic rainwater drainage system are directly connected to underground drainage pipes, two problems arise: First, the appearance of geysers at the water outlet poses a threat to public safety. When using siphonic rainwater systems on larger roofs, the flow rate at the end is large. This large flow directly into the outdoor inspection well causes a significant impact on the well walls, affecting structural stability. More importantly, the large flow cannot be quickly discharged due to limited downstream drainage capacity, leading to strong turbulence within the well and exacerbating drainage problems. In this situation, if the well is well-sealed, the manhole cover may be instantly blown off, causing a rapid gush of water; if the well is poorly sealed, a continuous fountain phenomenon will occur. Both phenomena are caused by a rapid increase in flow rate within the well, and this is known as the geyser phenomenon.

[0004] For super high-rise buildings, the pipeline system has a long flow path. When in an intermittent siphon drainage mode, severe uneven changes in water and air occur inside the system. The water-air ratio varies significantly at different elevations, which can easily lead to full pipe water columns or full pipe air columns. This can cause two problems: First, after rainwater falls rapidly from high elevations, the air inside the pipe is quickly pushed up. If the manhole is filled with water, intermittent springs mainly caused by the release of air bladders can easily occur in the inspection manhole. This situation is more likely to occur in actual applications and is more destructive. Second, when a full pipe water column of tens of meters directly enters the outlet well, the flow rate and velocity will increase rapidly, causing a huge impact on the outlet well.

[0005] Secondly, it cannot be coordinated with the construction of sponge city facilities. Sponge city construction emphasizes the infiltration, retention, storage, and purification of rainwater. For buildings, roof rainwater is guided from a high point to a low point for a series of treatments, typically achieved by disconnecting the rainwater downpipes at the lower level. However, for siphonic rainwater drainage systems with large flow rates and high velocities, existing rainwater disconnection technology that directly cuts off the downpipes cannot be used directly—it easily causes severe erosion of the ground, which is not only detrimental to the subsequent integration of sponge city facilities but also brings a series of safety problems.

[0006] Currently, siphonic rainwater drainage systems generally use underground energy dissipation pools for energy dissipation, but it is difficult to achieve surface disconnection and in-situ utilization, which is the sponge city concept of using sponge facilities on the surface to infiltrate, retain, store, and purify rainwater; on the other hand, underground energy dissipation pools occupy a large amount of underground space and involve a large amount of engineering work.

[0007] Patent document CN212427345U discloses a rainwater energy dissipation and recycling device, which includes a shell, a partition plate, and a pipeline assembly. The partition plate is arranged vertically inside the shell and connected to the bottom and side walls of the shell, dividing the shell into a first chamber and a second chamber. The volume of the first chamber is larger than the volume of the second chamber. The pipeline assembly includes an inlet pipe and an outlet pipe, which are respectively connected to the shell. The inlet pipe communicates with the first chamber, and the outlet pipe communicates with the second chamber. The outlet pipe is located at the bottom of the second chamber.

[0008] Because this patented technology uses a partition plate to dissipate rainwater energy through a downpipe in the first chamber, and then discharges the overflowing rainwater into the recessed green space in the second chamber, it can dissipate energy and slow down the flow of low-velocity rainwater. However, the following problems still exist: 1. For the rainwater downpipes of modern high-rise buildings, their height can reach 100 meters, by... v 2 =2gH indicates that the flow velocity of the water head can reach 40 m / s. Such a high flow velocity cannot be effectively dissipated by the isolation plate alone. The water waves or splashes formed by the impact of the outflowing water are very fast, and the second chamber cannot obtain a calm energy-dissipating water surface. The outflowing water in the outlet pipe is greatly disturbed. 2. The inlet pipe has an extremely high flow rate, while the outlet pipe has a relatively low flow rate, resulting in poor drainage capacity. Rainwater quickly fills the entire tank, and the pressure in the inlet pipe is directly transmitted to the outlet pipe, thus losing its energy dissipation function. Summary of the Invention

[0009] In view of the problems existing in the existing rainwater disconnection energy dissipation facilities, the technical problem to be solved by the present invention is to provide a disconnection energy dissipation facility for building siphon rainwater systems in sponge cities. It can not only dissipate energy from high-energy rainwater and reduce rainwater flow velocity to cooperate with subsequent low-impact development facilities, but also achieve large-flow rainwater outflow to prevent flow accumulation between the inlet and outlet pipes, and prevent rainwater from filling the box and causing energy dissipation failure.

[0010] To solve the above problems, the present invention adopts the following solution: The disconnected energy dissipation facility for the building siphon rainwater system used in sponge cities includes an energy dissipation box, an inlet pipe, a branch pipe, an inner main pipe, an outlet pipe, and a side wall outlet. The inlet pipe and outlet pipe are connected to the left and right side walls of the energy dissipation box in an alternating manner. The inlet pipe extends into the bottom of the energy dissipation box as a slanted tee for branching. The pipe extending straight along the inlet pipe is the branch pipe. The pipe extending obliquely upward from the inlet pipe is the inner main pipe. The upper end of the inner main pipe is connected to the outlet pipe. The side wall outlet is opened on the side wall of the energy dissipation box.

[0011] Preferably, the inclined tube wall of the inner chamber main pipe is provided with a water circulation port facing downwards and directly opposite the outlet of the diversion pipe, and a vent is vertically installed on the upper wall of the inclined tube of the inner chamber main pipe opposite to the water circulation port.

[0012] The technical effects of this invention are: This invention achieves energy reduction of high-energy siphon rainwater through automatic diversion and water circulation between the inner and outer energy dissipation chambers, enabling the siphon rainwater system to safely discharge water to outdoor sponge facilities; it also achieves large-scale discharge of inflow rainwater under high flow rates, avoiding the problems of intermittent springs caused by water backlog inside the facility and loss of energy dissipation function caused by rainwater filling the entire box. Attached Figure Description

[0013] The accompanying drawings of this invention are described below: Figure 1 This is a schematic diagram of the dual-splitter structure of the present invention; Figure 2 This is a schematic diagram of the single-splitter structure of the present invention; Figure 3 This is a structural diagram of a non-splitter energy dissipation chamber; Figure 4 A comparison diagram of the flow velocities at the sidewall outlet; Figure 5 This is a comparison chart of the flow velocities in the water outlet pipes.

[0014] In the diagram, 1 is the energy dissipation box, 2 is the water inlet pipe, 3 is the branch pipe, 4 is the main pipe in the inner chamber, 41 is the water circulation port, 42 is the vent, 5 is the water outlet pipe, 6 is the side wall water outlet, and 7 is the vent pipe. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments: To clearly describe the invention, this patent application uses the directional terms "upper," "lower," "front," and "rear" for distinction. These terms are determined based on the arrangement of the above figures. As the actual direction of use of the invention changes, the terminology of the orientation will also change, and this should not be regarded as a limitation on the scope of patent protection.

[0016] like Figure 1 As shown, the present invention includes an energy dissipation box 1, an inlet pipe 2, a diversion pipe 3, an inner chamber main pipe 4, an outlet pipe 5, and a side wall outlet 6. The inlet pipe 2 and outlet pipe 5 are staggered and connected to the left and right side walls of the energy dissipation box 1. The inlet pipe 2 extends into the lower part of the energy dissipation box 1 and is diverted by a slanted tee. The pipe extending straight along the inlet pipe 2 is the diversion pipe 3, and the pipe extending obliquely upward from the inlet pipe 2 is the inner chamber main pipe 4. The upper end of the inner chamber main pipe 4 is connected to the outlet pipe 5. A side wall outlet 6 is provided on the side wall of the energy dissipation box 1 for discharging rainwater after energy dissipation into the recessed green space. A vent pipe 7 is installed on the top surface of the energy dissipation box 1. The vent pipe 7 stabilizes the gaseous fluid flow field at the top of the inner cavity of the energy dissipation box 1, effectively mitigating the oscillation of the outlet water surface caused by poor venting.

[0017] The inner cavity of the energy dissipation box 1 forms the outer energy dissipation chamber. A portion of the rainwater from the inlet pipe 2, received from the branch pipe 3, undergoes flow energy reduction within the outer energy dissipation chamber. The inner main pipe 4 forms the inner energy dissipation chamber, where another portion of the rainwater flowing in from its opening undergoes flow energy reduction. When the rainwater kinetic energy in the inlet pipe 2 is high, the outflow rate of the branch pipe 3 is adjusted to ensure that the rainwater flowing into the outer energy dissipation chamber, after energy dissipation, meets drainage requirements. Another portion of the rainwater, after initial energy dissipation within the inner energy dissipation chamber of the inner main pipe 4, is discharged from the outlet pipe 5 and connected to the next stage of the disconnected energy dissipation facility of this invention, implementing secondary flow energy reduction. This avoids the problem of inlet pipe pressure being directly transmitted to the outlet pipe, causing loss of energy dissipation function, and ensures that the drainage from the side wall outlet 6 meets the water environment standards compatible with low-impact development facilities.

[0018] To further enhance energy dissipation, the inclined wall of the inner chamber main pipe 4 is provided with a downward-facing water circulation port 41. The water circulation port 41 intersects with the extension section of the branch pipe 3, and a vent 42 is vertically installed on the upper wall of the inclined pipe of the inner chamber main pipe 4 opposite to the water circulation port 41. Because the inner chamber main pipe 4 has a water circulation port 41 and a vent 42, the outer cavity energy dissipation chamber and the inner cavity energy dissipation chamber exchange liquid phase fluid through the water circulation port 41 and gas phase fluid through the vent 42.

[0019] How this structure works: The water circulation structure, composed of an inner and outer energy dissipation chamber, enables automatic hydraulic diversion of the incoming flow. Under normal inflow conditions, a portion of the flow enters the outer energy dissipation chamber through a diversion pipe, while the other portion enters the inner chamber's main pipe and then flows into the outer energy dissipation chamber through the water circulation port. Energy dissipation is enhanced through the collision of these two water streams. The flow then circulates along the chamber wall within the outer energy dissipation chamber before overflowing from the side outlet, achieving energy dissipation and velocity reduction. Under excessive flow conditions, most of the flow automatically flows from the inner chamber's main pipe 4 into the outlet pipe 5 for rapid discharge or is connected to the next stage of disconnected energy dissipation facilities. This avoids water backlog within the wall facilities, preventing the formation of intermittent springs. It overcomes the technical challenges of traditional energy dissipation models, which struggle to control intermittent springs caused by large outflows, and existing rainwater disconnection models, which struggle to connect with subsequent low-impact development (LID) facilities due to high-velocity outflows.

[0020] like Figure 1 As shown, the side wall outlets 6 are located on the front and rear side walls of the energy dissipation box 1. The two side wall outlets 6 are set at the same height. The bottom elevation of the side wall outlets 6 is higher than the outdoor ground elevation, and the top elevation of the side wall outlets is lower than the bottom elevation of the outlet pipe. This ensures that under normal inflow conditions, as much rainwater as possible can enter the external energy dissipation chamber and be discharged through the side outlets.

[0021] The inlet pipe 2 and the outlet pipe 5 are arranged parallel to each other. The diameter of the outlet pipe 5 is not smaller than that of the inlet pipe 2. On the one hand, the outflow velocity is further reduced by increasing the cross-sectional area of ​​the flow. On the other hand, the increased pipe diameter can further enhance the safe discharge capacity under extreme inflow conditions. The inlet pipe 2 is equipped with a flange at its front end, which connects to the building's rainwater downpipe. Rainwater enters the inlet pipe 2 through the flange.

[0022] Simulation Experiment: Comparison of Energy Dissipation Effects of Three Energy Dissipation Facilities This simulation experiment was conducted on the ANSYS three-dimensional fluid dynamics model simulation platform.

[0023] The basic parameters of the energy dissipation facilities in this simulation experiment are shown in the table below. 1. Energy dissipation box 700 mm × 700 mm × 1000 mm 2. Water inlet pipe DN 200 3. Diverter pipe DN 200 (same size as inlet pipe) 4. Internal Affairs Supervisor DN 200~DN 300 gradually expanding pipe 41. Water circulation port DN 200 5. Water outlet pipe DN 300 6. Side wall water outlet 500 mm × 100 mm 7. Ventilation tube DN 100 Figure 1 To create a water circulation port (referred to as dual diversion) on the main water pipe in the inner room; Figure 2This is a structural diagram of the single-flow energy dissipation chamber of the present invention (hereinafter referred to as single-flow). Figure 3 This is a structural diagram of a non-splitting energy dissipation chamber (referred to as the reference type). The inlet is the front end of the inlet pipe, and the outlet is divided into two types: the side wall outlet and the outlet pipe outlet.

[0024] Six influent flow rate gradients were set up to investigate the facility operation under different influent flow rate gradients: 45 L / s, 60 L / s, 75 L / s, 90 L / s, 120 L / s, and 150 L / s (equivalent to flow velocities of 1.5 m / s, 2 m / s, 2.5 m / s, 3 m / s, 4 m / s, and 5 m / s, respectively). The velocity variation at the six sidewall outlets is shown in [reference needed]. Figure 4 The flow velocity changes in outlet pipe 5 are shown in the diagram. Figure 5 .

[0025] from Figure 4 and Figure 5 It can be seen that the dual-flow and single-flow systems significantly outperform the control type without an inner chamber main pipe structure in terms of water velocity reduction. At the side wall outlets, the dual-flow and single-flow systems reduce the flow velocity by approximately 40% compared to the control type; at the outlet pipe, the dual-flow system reduces the velocity by approximately 50% compared to the control type, and the single-flow system reduces it by approximately 25%. Furthermore, the dual-flow system exhibits more stable velocity changes throughout the entire process. In summary, the inner chamber main pipe structure of this invention significantly improves energy dissipation and velocity reduction, resulting in an outlet flow velocity below 1 m / s, making it suitable for integration with subsequent sponge city infrastructure.

[0026] If the flow velocity in the inlet pipe is too high, a multi-stage disconnection energy dissipation facility is used in series. The diameter of the branch pipe in the previous stage is reduced to reduce the kinetic energy of the water entering the first-stage energy dissipation box, so that the next stage can continue to dissipate energy until the water supply requirements of the sponge facility are met.

Claims

1. A disconnected energy dissipation facility for building siphon rainwater systems in sponge cities, comprising an energy dissipation box (1) and an inlet pipe (2), characterized in that: It also includes a diversion pipe (3), an inner chamber main pipe (4), an outlet pipe (5) and a side wall outlet (6). The left and right side walls of the energy dissipation box (1) are connected to the inlet pipe (2) and the outlet pipe (5) in an alternating manner. The inlet pipe (2) extends into the bottom of the energy dissipation box (1) as a diagonal tee for diversion. The pipe extending straight along the inlet pipe (2) is the diversion pipe (3). The pipe extending obliquely upward from the inlet pipe (2) is the inner chamber main pipe (4). The upper end of the inner chamber main pipe (4) is connected to the outlet pipe (5). The side wall outlet (6) is opened on the side wall of the energy dissipation box (1). The inclined wall of the inner chamber main pipe (4) is provided with a downward-facing water circulation port (41). The water circulation port (41) intersects with the extension section of the branch pipe (3). A vent (42) is vertically installed on the upper wall of the inclined pipe of the inner chamber main pipe (4) opposite to the water circulation port (41). It also includes a vent pipe (7), which is installed on the top surface of the energy dissipation box (1).

2. The disconnection energy dissipation facility for building siphon rainwater systems in sponge cities according to claim 1, characterized in that: The side wall outlets (6) are located on the front and rear side walls of the energy dissipation box (1). The two side wall outlets (6) are set at the same height. The bottom elevation of the side wall outlets (6) is higher than the outdoor ground elevation, and the top elevation of the side wall outlets (6) is lower than the bottom elevation of the outlet pipe.

3. The disconnection energy dissipation facility for building siphon rainwater systems in sponge cities according to claim 2, characterized in that: The inlet pipe (2) and the outlet pipe (5) are set in parallel, and the diameter of the outlet pipe (5) is not less than that of the inlet pipe (2).

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