A multi-vertical slot fishway with V-shaped baffles and short baffles

Abstract

The present invention belongs to the field of fish passing facilities, and relates to a multi-vertical slit fishway with V-shaped baffles and short baffles, including a bottom plate, a side wall surface, a long side baffle, a V-shaped baffle, and a short side baffle. The present invention reasonably arranges the V-shaped baffles and the short baffles so that the water flow is diverted and converged after entering the fishway, so that the water flow is fully mixed, the water flow energy is effectively dispersed, and the flow velocity and turbulent kinetic energy in the pool chamber are reduced. Two symmetrically distributed vertical slit channels are provided in the pool chamber, which can adapt to changes in different water levels, meet the migration needs of different fish, and improve the use efficiency of the fishway. The present invention is not only conducive to the smooth migration of fish with weaker swimming ability, but also can ensure effective operation under low flow, and has significant economic benefits for areas with scarce water resources or high power generation demand.

Description

Technical Field

[0001] The invention belongs to the technical field of fishways, and relates to a multi-vertical-slot fishway with V-shaped baffles and short baffles. Background Art

[0002] Artificial obstacles in rivers have relevant adverse effects on fish migration routes, and the disruption of natural river longitudinal connectivity is considered to be one of the main reasons for the decline of freshwater fish populations. In order to restore the longitudinal connectivity of rivers divided by artificial obstacles to an acceptable level, the construction of effective fish passes is the best practice when it is not possible to remove the obstacles. The design of fish passes must take into account the biological characteristics of migratory fish, namely their swimming ability, size, and the response of fish to external stimuli such as turbulence, water acceleration and speed.

[0003] Statistics show that there are three main types of common fishways used in engineering: Daniel fishway, pool weir fishway, and vertical slot fishway. The characteristics of the three common types of fishways are summarized as follows: 1) Daniel fishway occupies a small area and is not restricted by space, but is easily affected by water level changes and easily clogged by sediments and debris. In addition, this design requires a higher water level. 2) Pool weir fishways have a smaller water flow section, which is prone to accumulate sediments and debris, causing orifice blockage and affecting water levels. This type of fishway is not suitable for larger water level fluctuations and cannot allow fish to cross the entire section. 3) Vertical slot fishways can adapt to larger and frequent water level fluctuations, allowing fish to move between different pools without jumping, suitable for swimming at any depth, and not prone to clogging. In addition, there are some combined fishways or new fishways, such as the piano-key weir combined orifice fishway in patent CN114370036A, which has good water level adaptability and can cope with water storage efficiency under large flow, but the orifice is easily blocked, affecting the operation of the fishway; such as the vertical slot fishway in patent CN117905030A, by changing the traditional vertical slot into a semicircular shape, so that the water flow rotates and flows downstream, dissipating the water flow energy, but its baffle and baffle structure is relatively complex, which is not conducive to engineering construction. Comprehensive analysis shows that the overwhelming advantage of VSF (Vertical Slot Fishway) fishway compared to other fishways is that it can adapt to water level changes while maintaining stable hydraulic performance. However, the operation of any fishway bypass system may lead to a reduction in the amount of water available for power generation, which will have a long-term economic impact on producers. Therefore, the goal of designing a fishway is to achieve biological effectiveness while minimizing the flow required for its operation. Summary of the invention

[0004] The present invention aims to provide a fishway suitable for fish with weaker swimming ability, and improve the effectiveness of the fishway operation. The present invention proposes a new type of multi-vertical slit fishway with V-shaped baffles and short baffles. Due to the presence of internal V-shaped baffles and short baffles, the water flow is first divided into two streams after entering the fishway and then merged to enter the next pool chamber. This design can effectively break the single directionality of the water flow, so that the energy of the water flow gradually decays through multiple turns and merges, thereby reducing the overall flow rate; it is conducive to the migration of fish with different swimming abilities, and is particularly suitable for fish with weaker swimming abilities. Entering the interior of the pool chamber, the two ends of the V-shaped baffle and the short baffle together form two vertical slit channels, which are symmetrically distributed, greatly improving the space utilization rate of the pool chamber, and fish can pass through at any water depth, which is conducive to speeding up the migration time of fish. This design retains the core advantages of the VSF fishway, which can not only operate effectively at a lower flow rate, but also significantly reduce the flow rate and turbulence in the pool chamber, which is of great significance for improving the efficiency of fish passage and protecting weak fish to migrate upstream smoothly.

[0005] In order to achieve the above object, the technical solution of the present invention is:

[0006] A multi-vertical-slot fishway with V-shaped baffles and short baffles, comprising a bottom plate 1, two side wall surfaces 2, a plurality of side long baffles 3, a plurality of V-shaped baffles 4 and a plurality of side short baffles 5; the two side wall surfaces 2 are located on both sides of the bottom plate 1, and together with the bottom plate 1, form a flow passage; the two side long baffles 3 are a group, the bottom ends of the side long baffles 3 are fixed to the upper surface of the bottom plate 1, and one side ends of the two side long baffles 3 are respectively fixed to the inner sides of the side wall surfaces 2, the two side long baffles 3 are symmetrically distributed along the transverse center line of the fishway, and the two side wall surfaces 2 ... Vertical gaps are left between the long side baffles 3, and the long side baffles 3 are perpendicular to the direction of water flow; multiple groups of long side baffles 3 are arranged on the bottom plate 1 at equal intervals to divide the fishway into multiple pool chambers; a V-shaped baffle 4 is arranged in the middle of each pool chamber, and a short side baffle 5 is symmetrically arranged on both sides of the V-shaped baffle 4, the short side baffle 5 is vertically connected to the side wall surface 2, a vertical gap is left between the short side baffle 5 and the V-shaped baffle 4, and the short side baffle 5 is longitudinally aligned with the two ends of the V-shaped baffle 4 close to the side wall surface 2; the directions of all V-shaped baffles 4 are consistent.

[0007] The centroid of the V-shaped baffle 4 coincides with the center of the pool chamber, the concave end faces upstream and the convex end faces downstream, and they are symmetrically distributed along the transverse center axis of the fishway. The tip of the concave end is opposite to the vertical seam between the two long side baffles 3, and the two edges of the convex surface of the V-shaped baffle 4 are respectively at an angle of 60° with the side wall surface 2 distributed on the same side of the transverse center axis; the thickness of the V-shaped baffle 4 is the same as the thickness of the long side baffle 3, and the longitudinal width of the V-shaped baffle 4 at both ends close to the side wall surface 2 is the same as the thickness of the short side baffle 5.

[0008] Furthermore, the longitudinal slope of the bottom plate 1 is 1% to 10%; the length-to-width ratio of each pool chamber is 6:5.

[0009] Furthermore, the ratio of the length dy1 of the long side baffle 3 to the width B of the pool chamber is 0.85:2, the ratio of the thickness dx1 of the long side baffle 3 to the length L of the pool chamber is 0.25:2.4; the ratio of the vertical seam width b between the long side baffles 3 symmetrically distributed along the transverse center line to the width B of the pool chamber is 0.3:2.

[0010] Furthermore, the ratio of the thickness dx1 of the V-shaped baffle 4 to the length L of the pool chamber is 0.25:2.4, the ratio of the longitudinal width dx2 of the V-shaped baffle 4 to the length L of the pool chamber is 0.29:2.4, the ratio of the distance l1 between the upstream concave end of the V-shaped baffle 4 and the longitudinal center axis of the pool chamber to the length L of the pool chamber is 0.06:2.4, the ratio of the distance l2 between the upstream concave end of the V-shaped baffle 4 and the upstream side long baffle 3 to the length L of the pool chamber is 1.13:2.4, and the ratio of the distance l3 between the downstream convex end of the V-shaped baffle 4 and the downstream side long baffle 3 to the length L of the pool chamber is 0.73:2.4.

[0011] Furthermore, the ratio of the length dy2 of the side short baffle 5 to the width B of the pool chamber is 0.3:2, the ratio of the thickness dx2 of the side short baffle 5 to the length L of the pool chamber is 0.29:2.4, and the ratio of the vertical seam width b between the side short baffle 5 and the V-shaped baffle 4 to the width B of the pool chamber is 0.3:2.

[0012] The beneficial effects of the present invention are:

[0013] (1) The present invention proposes a novel multi-vertical slot fishway with V-shaped baffles and short baffles, which can adapt to the changes in different water levels and operate effectively under low flow conditions. It is particularly suitable for areas with water shortage and high demand for power generation, and has significant economic and environmental benefits.

[0014] (2) By constructing V-shaped baffles and short baffles, the energy of the water flow can be effectively dispersed so that the energy of the water flow will not be released in a concentrated manner. After multiple turns and confluences, the energy of the water flow is greatly dissipated, which effectively slows down the speed of the water flow and reduces the turbulence intensity, thereby providing a more suitable upstream migration environment for fish with weaker swimming abilities. After entering the pool chamber from the long side baffle, two vertical slits are distributed at both ends of the V-shaped baffle, providing two channels, which speeds up the upstream passage time of fish and improves the utilization efficiency of the fishway. This design not only helps to disperse and attenuate the energy of the water flow, but also reduces the energy consumption of fish when passing through the fishway, reducing their risk of injury. In addition, unlike other combined fishways, the channels provided by the present invention are all vertical slits. The advantage of the vertical slit design is that it can meet the swimming needs of fish at any water depth without jumping, while reducing the risk of blockage. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1It is a three-dimensional schematic diagram of a single pool chamber structure of a multi-vertical slot fishway with a V-shaped baffle and a short baffle according to the present invention;

[0016] Figure 2 It is a two-dimensional plan view of a single pool chamber structure of a multi-vertical slot fishway with a V-shaped baffle and a short baffle according to the present invention;

[0017] Figure 3 It is a three-dimensional schematic diagram of a plurality of chamber structures of a multi-vertical-slot fishway with V-shaped baffles and short baffles according to the present invention;

[0018] Figure 4 It is a two-dimensional plan view of a plurality of chamber structures of a multi-vertical-slot fishway with V-shaped baffles and short baffles according to the present invention.

[0019] In the figure: 1, bottom plate; 2, side wall; 3, long side baffle; 4, V-shaped baffle; 5, short side baffle; the dotted line is the longitudinal center axis of a single pool chamber.

[0020] B-width of the pool chamber; L-length of the pool chamber; b-width of the vertical seam; dx1-thickness of the long side baffle and the V-shaped baffle; dy1-length of the long side baffle; dy2-length of the short side baffle; dx2-longitudinal width of the V-shaped baffle and thickness of the short side baffle; l1-distance between the upstream concave end of the V-shaped baffle and the longitudinal center axis of the pool chamber; l2-distance between the upstream concave end of the V-shaped baffle and the upstream long side baffle; l3-distance between the downstream convex end of the V-shaped baffle and the downstream long side baffle; the height of the side wall is H; the heights of the remaining baffles are all h. DETAILED DESCRIPTION

[0021] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and technical solutions.

[0022] like Figure 1-Figure 4 As shown, a novel multi-vertical slot fishway with V-shaped baffles and short baffles comprises a bottom plate 1, a side wall surface 2, a long side baffle 3, a V-shaped baffle 4, and a short side baffle 5, and all joints are fixed connections.

[0023] Figure 1The direction of the middle arrow is the direction of water flow. The longitudinal slope of the bottom plate of the fishway is 2.6%. The inlet water flows into the pool chamber from the vertical slit between the two long side baffles 3, and is divided into two streams in front of the V-shaped baffle 4, which flow into the two ends of the V-shaped baffle 4 close to the side wall and the two vertical slits formed by the short side baffles 5. Then the two streams reunite before passing through the next vertical slit. Since the entire fishway is symmetrical along the transverse central axis, the flow topology formed is also symmetrically distributed. Therefore, the following only describes the formation of a recirculation zone on one side; a larger recirculation zone is formed between the upstream long side baffle 3 and the middle short side baffle 5; then through the vertical slit, because the water flow reunites, two smaller recirculation zones are formed between the V-shaped baffle 4 and the downstream long side baffle 3, and between the short side baffle 5 and the downstream long side baffle 3 due to the mainstream.

[0024] Figure 2 It is a two-dimensional plan view of a single chamber structure of a novel multi-vertical slot fishway with V-shaped baffles and short baffles of the present invention. Chamber width B = 2.00m; chamber length L = 2.40m; vertical slot width b = 0.3m; thickness of the side long baffle and V-shaped baffle dx1 = 0.25m; length of the side long baffle dy1 = 0.85m; length of the side short baffle dy2 = 0.30m; longitudinal width of the V-shaped baffle and thickness of the side short baffle dx2 = 0.29m; distance l1 = 0.06m between the upstream concave end of the V-shaped baffle 4 and the longitudinal center axis of the chamber; distance l2 = 1.13m between the upstream concave end of the V-shaped baffle 4 and the upstream side long baffle 3; distance l3 = 0.73m between the downstream convex end of the V-shaped baffle 4 and the downstream side long baffle 3; height H = 3.2m of the side wall; height of the remaining baffles is h = 2.4m.

[0025] After the water flows into the pool, the structural design of the V-shaped baffle 4 and the short side baffle 5 disperses the water flow after entering the fishway, avoiding the concentrated release of water flow energy. At the same time, the water flow gradually decays after multiple turns and convergences, so that the flow velocity when passing through each vertical slit is reduced, which helps fish with smaller body size or weaker swimming ability to pass through the high-speed area smoothly. Symmetrical recirculation areas are formed on both sides of the V-shaped baffle 4. The larger recirculation area is located upstream of the V-shaped baffle 4, between the upstream long side baffle 3 and the middle short side baffle 5; downstream of the V-shaped baffle 4, between the V-shaped baffle 4 and the downstream long side baffle 3, and between the short side baffle 5 and the downstream long side baffle 3, a relatively small recirculation area is formed; these recirculation areas have low flow velocities and relatively weak turbulence intensity, and are distributed on both sides of the mainstream, so that fish can quickly find and rest during the upstream migration process, which helps fish maintain physical strength and successfully pass through the fishway.

[0026] Numerical simulation studies show that at flow rate Q = 0.46m 3 / s, slope S=2.6%, the comparison results of fishway running flow, average time-averaged water depth inside the pool, average time-averaged flow velocity, maximum time-averaged flow velocity, average time-averaged turbulent kinetic energy, maximum time-averaged turbulent kinetic energy, average time-averaged Reynolds shear stress, maximum time-averaged Reynolds shear stress, average unit volume turbulent dissipation rate and maximum unit volume turbulent dissipation rate are shown in Table 1:

[0027] Table 1 Comparison of water depth, operating flow, flow velocity, turbulent kinetic energy, Reynolds shear stress value and turbulent dissipation rate per unit volume of the two structural types of fishways.

[0028]

[0029] The research results show that, under the same operating water depth, the new multi-vertical slot fishway with V-shaped baffles and short baffles of the present invention reduces the required operating flow by 32.49% compared with the traditional single vertical slot fishway, which is particularly important for water-scarce areas and power generation areas that focus on economic benefits. At the same time, the eight indicators of this new fishway in the pool chamber - average time-averaged flow velocity, maximum time-averaged flow velocity, average time-averaged turbulent kinetic energy, maximum time-averaged turbulent kinetic energy, average time-averaged Reynolds shear stress, maximum time-averaged Reynolds shear stress, average unit volume turbulent dissipation rate and maximum unit volume turbulent dissipation rate - are all lower than those of the traditional single vertical slot fishway, indicating that the lower flow velocity in the pool chamber of the present invention is more suitable for fish with smaller body size and weaker swimming ability to migrate upstream; lower turbulent kinetic energy can help fish maintain higher physical strength, smaller Reynolds shear stress can help reduce the damage to fish when swimming upstream, and lower unit volume turbulent dissipation rate is conducive to fish in the process of upstream to maintain a stable posture and swimming trajectory, reduce energy consumption and potential damage to the body, thereby improving the success rate and effect of fish through the fishway.

Claims

1. A multi-vertical slot fishway with V-shaped baffles and short baffles, characterized in that: The multi-vertical-slot fishway comprises a bottom plate (1), two side walls (2), a plurality of long side baffles (3), a plurality of V-shaped baffles (4) and a plurality of short side baffles (5); the two side walls (2) are located on both sides of the bottom plate (1) and together with the bottom plate (1) form a flow passage; the two long side baffles (3) are arranged as a group, the bottom ends of the long side baffles (3) are fixed to the upper surface of the bottom plate (1), one side ends of the two long side baffles (3) are respectively fixed to the inner sides of the side walls (2), the two long side baffles (3) are symmetrically distributed along the transverse center line of the fishway, and the two long side baffles (3) are arranged to extend along the transverse center line of the fishway. A vertical gap is left between the side long baffles (3) and the direction of water flow; a plurality of groups of side long baffles (3) are arranged on the bottom plate (1) at equal intervals to divide the fishway into a plurality of pool chambers; a V-shaped baffle (4) is arranged in the middle of each pool chamber, and a side short baffle (5) is symmetrically arranged on both sides of the V-shaped baffle (4); the side short baffles (5) are vertically connected to the side wall surface (2), a vertical gap is left between the side short baffles (5) and the V-shaped baffles (4), and the two ends of the side short baffles (5) and the V-shaped baffles (4) close to the side wall surface (2) are aligned in the longitudinal direction; all the V-shaped baffles (4) are in the same direction; The centroid of the V-shaped baffle (4) coincides with the center of the pool chamber, the concave end faces upstream and the convex end faces downstream, and the V-shaped baffle (4) is symmetrically distributed along the transverse central axis of the fishway, the concave end tip is opposite to the vertical seam between the two side long baffles (3), and the two edges of the convex surface of the V-shaped baffle (4) are respectively at an angle of 60° with the side wall surface (2) distributed on the same side of the transverse central axis; the thickness of the V-shaped baffle (4) is the same as the thickness of the side long baffle (3), and the longitudinal width of the two ends of the V-shaped baffle (4) close to the side wall surface (2) is the same as the thickness of the side short baffle (5); The longitudinal slope of the bottom plate (1) is 1% to 10%.

2. A multi-vertical slot fishway with V-shaped baffles and short baffles according to claim 1, characterized in that: The length-to-width ratio of each pool chamber is 6:

5.

3. A multi-vertical slot fishway with V-shaped baffles and short baffles according to claim 1 or 2, characterized in that: The ratio of the length dy1 of the long side baffle (3) to the width B of the pool chamber is 0.85:2, the ratio of the thickness dx1 of the long side baffle (3) to the length L of the pool chamber is 0.25:2.4; the ratio of the width b of the vertical seams between the long side baffles (3) symmetrically distributed along the transverse center line to the width B of the pool chamber is 0.3:

2.

4. A multi-vertical slot fishway with V-shaped baffles and short baffles according to claim 1 or 2, characterized in that: The ratio of the thickness dx1 of the V-shaped baffle (4) to the length L of the pool chamber is 0.25:2.4, the ratio of the longitudinal width dx2 of the V-shaped baffle (4) to the length L of the pool chamber is 0.29:2.4, the ratio of the distance l1 between the upstream concave end of the V-shaped baffle (4) and the longitudinal center axis of the pool chamber to the length L of the pool chamber is 0.06:2.4, the ratio of the distance l2 between the upstream concave end of the V-shaped baffle (4) and the upstream side long baffle (3) to the length L of the pool chamber is 1.13:2.4, and the ratio of the distance l3 between the downstream convex end of the V-shaped baffle (4) and the downstream side long baffle (3) to the length L of the pool chamber is 0.73:2.

4.

5. A multi-vertical slot fishway with V-shaped baffles and short baffles according to claim 1 or 2, characterized in that: The ratio of the length dy2 of the side short baffle (5) to the width B of the pool chamber is 0.3:2, the ratio of the thickness dx2 of the side short baffle (5) to the length L of the pool chamber is 0.29:2.4, and the ratio of the vertical seam width b between the side short baffle (5) and the V-shaped baffle (4) to the width B of the pool chamber is 0.3:2.

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