Fish collecting system

Abstract

The invention provides a fish collecting system which is provided with a water flow inlet, a water flow outlet and a water flow channel, and a blocking piece used for blocking fishes is arranged on the water flow channel. A first water flow opening is formed in the blocking piece; the water flow inlet is formed in the tail water tunnel outlet, or the water flow inlet is formed in the position, close to the tail water tunnel outlet, in the tail water channel; a fish accommodating space communicated with the water flow channel is formed on one side of the water flow channel; the water flow outlet forms a first fish inlet, and a fish flowing channel is formed between the first fish inlet and the fish containing space. The fish flowing channel is located on the downstream side of the blocking piece. The fish collecting system further comprises a drainage structure extending from the water flow inlet to the downstream of the water flow outlet. The fish containing space and the drainage structure are located on the two sides of the water flow channel respectively. The distance between the drainage structure and the fish containing space in the width direction of the tail water channel is gradually increased from the position, where the water flow outlet is formed, of the drainage structure to the end, located on the downstream side, of the drainage structure.

Description

Technical Field

[0001] The invention relates to the technical field of water conservancy and hydropower engineering, and in particular to a fish collecting system for a hydropower station. Background Art

[0002] As we all know, while hydropower stations play their role in flood control, power generation, and shipping, they also have an impact on the ecological environment that cannot be ignored. In particular, the process of fish migrating upstream to find spawning grounds will be blocked by dams. Building fish gathering facilities is one of the effective measures to mitigate the impact of hydropower projects on fish. For hydropower stations with a head of more than 100m, fish gathering measures such as fish lifts or fish gathering systems are often used in combination with the site conditions of the power station and the characteristics of the hub layout. As a type of fish gathering facility, the fish gathering and transportation system is a variation of the fish lift, which is generally composed of a fish gathering ship and a fish transport ship connected front and back.

[0003] The key to the successful design of fish gathering system is water flow condition. Good water flow condition is the key to attracting fish. The inlet of fish gathering system generally adopts a water flow that has an attractive effect on fish to attract fish, but the flow rate should not be too large. Exceeding the rapid swimming speed of the fish may cause the fish to be unable to enter. At present, most fish gathering facilities use pump station water replenishment system to form fish attracting flow to meet the water flow condition requirements of the fish inlet and fish gathering channel of the fish gathering tank. The water replenishment generally comes from the upstream reservoir area or the construction of pump station water supply. The construction cost and operation cost of the water replenishment system are high, and the economic efficiency is poor.

[0004] A patent application with application number CN201910133528.9 and name “A fish collecting box and fish collecting method for collecting fish using tailwater” discloses a method of directly using a fish collecting box to collect fish. The tailwater from power generation enters the fish collecting box to form a fish-attracting water flow, and the fish's tendency to flow is used to collect fish. No additional water is required, saving project operating costs.

[0005] However, since the fish collecting box is placed in the draft tube or the tailrace tunnel of the power house, there are still the following deficiencies: ① When the fish collecting box is placed in the draft tube or the tailrace tunnel of the power house, it is impossible to well control the fish attracting flow rate. When the unit is operating at full load, the flow velocity at the outlet of the tailrace tunnel is generally between 4 m / s and 5 m / s, while the optimal fish attracting flow velocity for general fish is between 1 m / s and 2 m / s. There is a problem that the fish attracting flow velocity in the fish collecting channel is too large, and at the same time, it is impossible to dynamically adjust according to the different fish attracting flow velocities at different water depths; ② When the fish collecting box is placed in the draft tube or the tailrace tunnel of the power house, the difference between the downstream flow field and the tailwater flow field is small, and it is difficult for fish to sense the flow field difference and find the fish inlet, which affects the fish attracting effect; ③ When the operating mode of the power station unit is different, the flow velocity in the tailrace tunnel changes greatly. At this time, it is very difficult for fish to find the fish inlet, and the fish attracting effect varies greatly; ④ It is difficult for the fish collecting box to collect fish at different water depths, and the fish collecting range is limited; ⑤ When the fish collecting box is placed in the draft tube or the tailrace tunnel of the power house, the water blocking effect is obvious, the head loss is large, which will cause the backwater of the downstream water level and affect the power generation benefit. Summary of the Invention

[0006] The problem to be solved by the present invention is to provide a fish collecting system for at least one of the above problems existing in the existing fish collecting system that places the fish collecting box in the draft tube or the tailrace tunnel of the power house.

[0007] To solve the above technical problems, the technical solution adopted by the present invention is: a fish collecting system, the fish collecting system having a water flow inlet, a water flow outlet, and a water flow channel connected between the water flow inlet and the water flow outlet; a blocking member for blocking fish is provided on the water flow channel, and a first water flow port is opened on the blocking member; the water flow inlet is arranged at the outlet of the tailrace tunnel, so that a part of the water flow channel is located in the tailrace tunnel, or the water flow inlet is arranged at a position in the tailrace canal close to the outlet of the tailrace tunnel; A fish accommodating space communicating with the water flow channel is formed on one side of the water flow channel; the water flow outlet forms a first fish inlet, and a fish flow channel is formed between the first fish inlet and the fish accommodating space; the fish flow channel is located on the downstream side of the blocking member; the fish collecting system further includes a drainage structure extending from the water flow inlet to the downstream of the water flow outlet; the fish accommodating space and the drainage structure are respectively located on both sides of the water flow channel; from the position where the drainage structure forms the water flow outlet to the end of the drainage structure on the downstream side, the distance between the drainage structure and the fish accommodating space in the width direction of the tailrace canal gradually increases.

[0008] In the above technical solution, the drainage structure is a drainage wall, the fish collecting system includes a fish collecting device, the fish collecting device extends in the length direction of the tailrace tunnel, and a groove is formed on the side of the fish collecting device facing the water flow channel, and the groove forms the fish accommodating space.

[0009] In the above technical solution, the drainage structure is a drainage wall, and the drainage wall includes a first section of the drainage wall provided at the water inlet; when viewed from the top of the fish collection system, the distance between the first section of the drainage wall and the fish accommodation space in the width direction of the tailrace gradually increases from the end close to the water inlet to the end far from the water inlet of the first section of the drainage wall.

[0010] In the above technical solution, the drainage wall includes a first section of the drainage wall, a second section of the drainage wall, and a third section of the drainage wall connected in sequence; the first section of the drainage wall and the third section of the drainage wall are respectively located on the upstream side and the downstream side of the second section of the drainage wall; the second section of the drainage wall extends in the length direction of the tailrace tunnel; when viewed from the top of the fish collection system, the distance between the third section of the drainage wall and the fish accommodation space in the width direction of the tailrace gradually increases from the end close to the water inlet to the end far from the water inlet of the third section of the drainage wall; wherein, the connection between the second section of the drainage wall and the third section of the drainage wall is flush with the water outlet, or the connection between the second section of the drainage wall and the third section of the drainage wall is located on the upstream side of the water outlet.

[0011] In a structural form of the above technical solution, a gate structure for adjusting the width of the water inlet is installed on the drainage structure; the fish collection system is arranged in the tailrace, the water inlet faces the outlet of the tailrace tunnel, the fish collection device is arranged close to a side wall of the tailrace, the water flow channel and the side wall of the tailrace are respectively located on both sides of the fish collection device, and the water inlet is formed between the gate structure and the downstream end of the tailrace tunnel; Or adopt the following structural form: a gate structure for adjusting the width of the water inlet is installed on the drainage structure; at least part of the drainage structure and the gate structure extend into the tailrace tunnel, and the water inlet is formed between the gate structure and the side wall of the tailrace tunnel.

[0012] In a structural form of the above technical solution, a fish collection box is arranged in the fish accommodation space, the upper end of the fish collection box is open, and the fish collection system further includes a lifting device for adjusting the height position of the fish collection box in the height direction; when the fish collection box is at the lowest height position, the height of the fish flow channel between the water outlet and the blocking member is not lower than the height of the top end of the fish collection box; In another structural form of the above technical solution, the fish collection device is further connected with a baffle; the baffle has a first state and a second state; when the baffle is in the first state, the fish accommodation space is communicated with the water flow channel; when the baffle is in the second state, the baffle separates the fish accommodation space and the water flow channel. In addition, the fish collection box and the baffle can also be arranged simultaneously.

[0013] In the above technical solution, the fish collecting system includes a flared structure; the opening size of the first end of the flared structure is larger than the opening size of the second end of the flared structure; the opening of the first end of the flared structure forms the first fish inlet, and the opening of the second end of the flared structure forms the second fish inlet; the first fish inlet is communicated with the fish accommodating space through the second fish inlet; the first fish inlet is located on the downstream side of the second fish inlet.

[0014] In the above technical solution, a mounting member connected to the flared structure is provided on the water flow channel; the opening of the second end of the flared structure is located at the position where the flared structure is connected to the mounting member; the part of the mounting member located outside the second end opening is used to block fish and forms a second water flow port; a third water flow port is formed on the side wall of the flared structure.

[0015] In the above technical solution, the width and height of the second fish inlet are 2 to 3 times the body length of the largest fish collecting object; the width of the first fish inlet is 3 to 4 times the width of the second fish inlet, and the height of the first fish inlet is 3 to 4 times the height of the second fish inlet.

[0016] In the above technical solution, the diversion structure is installed with M gate structures for adjusting the width of the water flow inlet and M×N second fish inlets; the M gate structures are arranged in sequence in the height direction to form an M-layer structure, and the gate structure control units corresponding to each gate structure are independently arranged; each second fish inlet forms an overall structure with M layers and N columns; M≥2, N≥1; the second fish inlet located on the m-th layer in the overall structure is at the same height as the m-th gate structure, 1≤m≤M; in the overall structure, the second fish inlets located on the same layer are arranged in sequence in the width direction of the tail water channel; The width of the position corresponding to the m-th layer gate structure in the water flow inlet is: e_m=(k_m×N×V_m×D×H×W1×(ku×((W2×H2) / (W1×H1))-ku+1)) / Q; Where: k_m is the flow velocity change coefficient corresponding to the height position where the second fish inlet on the m-th layer is located; V_m is the optimal fish attracting flow velocity corresponding to the height position where the second fish inlet on the m-th layer is located; D is the width of the tail water tunnel; H is the water depth at the outlet of the tail water tunnel; Q is the power generation tail water flow; W1 is the width of the second fish inlet, H1 is the height of the second fish inlet, W2 is the width of the first fish inlet, H2 is the height of the first fish inlet, and ku is the porosity of the blocking member; When the height position of the first fish inlet on the m-th layer is not higher than the elevation of the tail water tunnel outlet, the value range of k_m is [1, 1.2], and when the height position of the first fish inlet on the m-th layer is higher than the elevation of the tail water tunnel outlet, the value range of k_m is [1.2, 1.5].

[0017] The fish-aggregating system provided by the present invention mainly has the following advantages: (1) The diversion structure involved in the present invention can effectively reduce the flow rate of the tail water, enabling an optimal fish-attracting flow velocity at the water flow outlet serving as the first fish inlet, making it easier to attract fish and improving the fish-aggregating efficiency; (2) The diversion structure involved in the present invention can keep the main flow of the tail water away from the first fish inlet, thereby generating an obvious flow velocity gradient between the first fish inlet and the surrounding flow field and enhancing the fish-attracting effect; (3) The multi-layer door structure involved in the present invention can dynamically adjust the flow rate of the tail water introduced into each layer. Under different power generation flow rates of the power station, the fish-attracting flow rate can be controlled by adjusting the width of the water flow inlet, and fish aggregation can be achieved at different times; (4) The present invention can be arranged with multiple first fish inlets in layers, and the fish-attracting flow velocities of the multiple first fish inlets can be dynamically adjusted according to the fish distribution in water layers. The fish-attracting flow field is more targeted, thus achieving intelligent fish attraction; (5) The present invention can minimize the impact on the tail water level to the greatest extent while ensuring the fish-attracting flow rate, avoiding the backwater elevation of the tail water, and thus increasing the power generation benefit of the power station. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1 It is a top view schematic diagram of the fish-aggregating system, tail water tunnel, and tail water canal in Embodiment 1 of the present invention; Figure 2 It is Figure 1 a partial three-dimensional structure schematic diagram of; Figure 3 It is a three-dimensional structure schematic diagram of two different fish-aggregating systems and the corresponding tail water tunnel and tail water canal in Embodiment 1 of the present invention; Figure 4 It is Figure 1 a front view schematic diagram of the blocking member in; Figure 5 It is Figure 1 a three-dimensional structure schematic diagram of the flared structure in; Figure 6 It is Figure 1 a front view schematic diagram of the mounting member in; Figure 7 It is a velocity contour map of the horizontal section (perpendicular to the height direction) obtained when applying the fish-aggregating system in Embodiment 1 of the present invention; Figure 8 It is a velocity cloud diagram of a cross-section (perpendicular to the length direction of the tailrace tunnel) when looking from the water flow outlet to the water flow inlet when applying the fish collection system of Embodiment 1 of the present invention; Figure 9 It is a top view schematic diagram of the fish collection system, tailrace tunnel, and tailrace canal of Embodiment 2 of the present invention; Figure 10 It is a partial top view of the fish collection system when the baffle of Embodiment 3 of the present invention is in the first state; Figure 11 It is a partial top view of the fish collection system when the baffle of Embodiment 3 of the present invention is in the second state; Figure 12 It is a front view schematic diagram of the blocking member of Embodiment 4 of the present invention; The meanings of the reference numerals in the figure are as follows: 1, the first section of the diversion wall; 2, the second section of the diversion wall; 3, the third section of the diversion wall; 4, the control platform; 5, the flared structure; 51, the first fish inlet; 52, the second fish inlet; 5A, the first guiding structure; 5B, the second guiding structure; 6, the door structure; 61, the water flow inlet; 7, the fish collection device; 71, the baffle; 72, the first guiding groove; 73, the second guiding groove; 91, the blocking member; 91A, the first connecting rod; 92, the mounting member; 92A, the second connecting rod; 11, the fish accommodation space; 12, the fish collection box; 100, the tailrace tunnel; 101, the tailrace tunnel outlet; 102, the side wall surface of the tailrace tunnel; 200, the tailrace canal; 201, the end face of the tailrace canal; 202, the side wall surface of the tailrace canal; 301, the first water flow port; 302, the second water flow port; 303, the third water flow port; L1, the length direction of the tailrace tunnel; L2, the width direction of the tailrace canal; L3, the height direction. Detailed implementation manners

[0020] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0021] Embodiment 1 As Figures 1 - 3 shown, Embodiment 1 of the present invention provides a fish collection system, and the fish collection system has a water flow inlet 61, a water flow outlet, and a water flow channel connected between the water flow inlet 61 and the water flow outlet.

[0022] The fish collection system further includes a diversion structure disposed on one side of the water inlet 61. A blocking member 91 for blocking fish is provided on the water flow channel. The blocking member 91 is used to block the swimming of fish from the downstream side to the upstream side of the blocking member 91. A first water flow port 301 is formed on the blocking member 91. The water inlet 61 is communicated with the water outlet through the first water flow port 301. A part of the water flow channel between the first water flow port 301 and the water outlet is disposed in the tail water channel 200. The fish collection system further includes a diversion structure extending from the water inlet 61 to a position downstream of the water outlet. From the position where the diversion structure forms the water outlet to the downstream end of the diversion structure, the distance between the diversion structure and the fish accommodation space 11 in the width direction L2 of the tail water channel gradually increases. The diversion structure is used to guide the water flow at the water outlet position to a position away from the water outlet. The diversion structure is also used to guide the water flow to a position away from the water inlet 61. When fish swim from the downstream river to the tail water channel, due to the upstream habit of fish, when they encounter a suitable flow velocity field in the tail water channel, they will continue to swim upstream. Therefore, they will not enter through the water inlet 61, but only enter the fish flow channel through the first fish inlet 51. The third section 3 of the diversion wall is used to separate the main flow on the tail water side and the fish attracting water flow on the fish collection system side, and a significant flow velocity difference can be formed at the water outlet.

[0023] The water inlet 61 is disposed at a position in the tail water channel 200 close to the outlet 101 of the tail water tunnel, so that the entire fish collection system is within the scope of the tail water channel 200.

[0024] A fish accommodation space 11 communicated with the water flow channel is formed on one side of the water flow channel. The water outlet serves as the first fish inlet 51, and a fish flow channel is formed between the first fish inlet 51 and the fish accommodation space 11. The fish flow channel is located on the downstream side of the blocking member 91. Figure 1 The solid arrows on the water flow channel show the water flow direction, and the dashed arrows show the swimming direction of fish from the first fish inlet 51 into the fish accommodation space 11.

[0025] According to the above solution of the present invention, since fish prefer to swim upstream, using the water outlet as the first fish inlet enables fish to enter through the first fish inlet that serves as the water outlet, realizing upstream swimming. Through the setting of the diversion structure, the water flow at the water inlet position can be guided to a position away from the water inlet, thereby reducing the flow velocity at the water inlet position and making the outflow velocity reach a more suitable fish attracting velocity to attract fish into the fish collection system. Since the fish accommodation space is located on one side of the water flow channel, that is, avoiding the position of the water flow channel, the water flow velocity in the fish accommodation space is small, which is convenient for collecting fish after they swim. The present invention separates the tail water flow from the tail water tunnel through the diversion structure and only quotes part of the flow rate.

[0026] The water diversion structure is a water diversion wall. The fish collection system includes a fish collection device 7, which extends in the length direction L1 of the tailrace tunnel. A groove is formed on the side of the fish collection device 7 facing the water flow channel, and the groove forms the fish accommodation space 11. The length direction L1 of the tailrace tunnel is the length direction of the tailrace tunnel 100. The fish collection device 7 and the water diversion structure are respectively located on both sides of the water inlet 61. The water flow channel is located between the fish collection device 7 and the water diversion wall.

[0027] According to the above solution of the present invention, the groove is formed by the fish collection device, that is, the groove is located on one side of the water flow channel, avoiding the position with a relatively large flow velocity, so that the flow velocity in the groove is relatively small, which is suitable for collecting fish.

[0028] The water diversion structure is a water diversion wall, and the water diversion wall includes a first section 1 of the water diversion wall provided at the water inlet 61. The first section 1 of the water diversion wall extends downstream from the position of the water inlet 61. From the top view direction of the fish collection system, from one end of the first section 1 of the water diversion wall close to the water inlet 61 to the other end far from the water inlet 61, the distance between the first section 1 of the water diversion wall and the fish collection device 7 in the width direction L2 of the tailrace channel gradually increases. The width direction L2 of the tailrace channel is parallel to the width direction of the tailrace tunnel.

[0029] According to the above solution of the present invention, through the setting of the water diversion wall, the water flow at the water inlet position can be guided to a position far from the water inlet as much as possible, thereby reducing the flow velocity at the water inlet position.

[0030] The water diversion wall includes a first section 1 of the water diversion wall, a second section 2 of the water diversion wall, and a third section 3 of the water diversion wall connected in sequence. The first section 1 of the water diversion wall and the third section 3 of the water diversion wall are respectively located on the upstream side and the downstream side of the second section 2 of the water diversion wall. The second section 2 of the water diversion wall extends in the length direction L1 of the tailrace tunnel. From the top view direction of the fish collection system, from one end of the third section 3 of the water diversion wall close to the water inlet 61 (i.e., the connection position of the second section 2 and the third section 3 of the water diversion wall) to the other end far from the water inlet 61 (i.e., the end of the third section 3 of the water diversion wall located on the downstream side), the distance between the third section 3 of the water diversion wall and the fish collection device 7 in the width direction L2 of the tailrace channel gradually increases. In this embodiment, the connection position of the second section 2 and the third section 3 of the water diversion wall is flush with the water outlet (as Figure 1 shown). It is also possible to set the connection position of the second section 2 and the third section 3 of the water diversion wall on the upstream side of the water outlet.

[0031] According to the above solution of the present invention, the first section 1 of the water diversion wall is used to reduce the diversion flow; the second section 2 of the water diversion wall is used to separate the fish-attracting water flow and the main tail water flow, and the third section 3 of the water diversion wall is used to guide the main flow on the tail water side and the fish-attracting water flow on the fish collection system side to be separated, so that a significant flow velocity difference can be formed at the water outlet.

[0032] The drainage structure is equipped with a door structure 6 for adjusting the width of the water flow inlet 61.

[0033] According to the above solution of the present invention, by adjusting the width of the water flow inlet, the regulation of the inlet flow rate is achieved.

[0034] Viewed from the top-down direction of the fish collection system, the door structure 6 can be an arc structure. The drainage structure is equipped with M door structures 6 for adjusting the width of the water flow inlet 61 and M×N second fish inlets 52; the M door structures 6 are arranged in sequence in the height direction to form an M-layer structure, and the door structure control units corresponding to each door structure 6 are independently arranged, so that the opening degree of the position of the water flow inlet 61 corresponding to each door structure 6 can be adjusted; each of the second fish inlets 52 forms an overall structure with M layers and N columns; M≥2, N≥1; the second fish inlet 52 located in the m-th layer in the overall structure is at the same height as the m-th door structure 6, 1≤m≤M; in the overall structure, the second fish inlets 52 located in the same layer are arranged in sequence in the width direction L2 of the tailrace. In this embodiment 1, M is 9 and N is 2.

[0035] The width of the position in the water flow inlet 61 corresponding to the m-th layer door structure 6 is: e_m=(k_m×N×V_m×D×H×W1×(ku×((W2×H2) / (W1×H1))-ku+1)) / Q; Where: k_m is the flow velocity change coefficient corresponding to the height position where the second fish inlet in the m-th layer is located; V_m is the optimal fish attracting flow velocity corresponding to the height position where the second fish inlet 52 in the m-th layer is located; D is the width of the tailwater tunnel 100; H is the water depth at the outlet 101 of the tailwater tunnel; Q is the power generation tailwater flow rate (i.e., the power generation flow rate of the power station unit upstream of the fish collection system); W1 is the width of the second fish inlet 52, H1 is the height of the second fish inlet 52, W2 is the width of the first fish inlet 51, H2 is the height of the first fish inlet 51, and ku is the porosity of the blocking member 91. The height position where the second fish inlet in the m-th layer is located can be the height position of the center of the second fish inlet in the m-th layer. Since the door structure is M layers, the water flow inlet 61 can also be regarded as M layers, that is, by adjusting the opening degree of each door structure, the width of the water flow inlet 61 at the corresponding height position is adjusted.

[0036] When the height position of the first fish inlet 51 in the m-th layer is not higher than the elevation of the outlet 101 of the tailwater tunnel, the value range of k_m is [1, 1.2]; when the height position of the first fish inlet 51 in the m-th layer is higher than the elevation of the outlet 101 of the tailwater tunnel, the value range of k_m is [1.2, 1.5].

[0037] According to the above solution of the present invention, the water inlet widths of the door structures at different layers can be set differently, so that the water inlet widths of the door structures at different depths can be independently controlled. The water inlet width of the door structure can be adjusted accordingly according to the water flow velocity suitable for the swimming of fish at different depth positions, which is suitable for collecting fish at different depth positions. In this embodiment, the height direction L3 is the water depth direction.

[0038] The water inlet width of the door structure 6 is \(e_m=(k_m×N×V_m×D×H×W1×(ku×((W2×H2) / (W1×H1)) - ku + 1)) / Q\); where: D is the width of the tailrace tunnel 100; H is the water depth at the outlet 101 of the tailrace tunnel; W1 is the width of the second fish inlet 52; H1 is the height of the second fish inlet 52; W2 is the width of the first fish inlet 51; H2 is the height of the first fish inlet 51; the first fish inlet 51 is arranged in N columns; the porosity of the blocking member 91 (which can be an escape prevention fence) is ku; k is the flow velocity change coefficient; Q is the generating flow of the unit; V is the optimal fish attracting flow velocity corresponding to the height position of the second fish inlet 52. When the height position where the second fish inlet 52 is located is not higher than the elevation of the outlet 101 of the tailrace tunnel, k the value range of is [1, 1.2]. When the height position where the second fish inlet 52 is located is higher than the elevation of the outlet 101 of the tailrace tunnel, k the value range of is [1.2, 1.5]. The water inlet width is the opening size of the water inlet 61 in the width direction L2 of the tailrace canal.

[0039] According to the above solution of the present invention, by setting the water inlet width of the door structure, the flow velocity of the water inlet can be adjusted, and the optimal fish attracting flow velocity of fish at the corresponding height can be achieved.

[0040] The fish collecting system is arranged in the tailrace canal 200. The water inlet 61 faces the outlet 101 of the tailrace tunnel. The fish collecting device 7 is arranged close to one side wall surface 202 of the tailrace canal. The first section 1 of the diversion wall and the one side wall surface 202 of the tailrace canal are respectively located on both sides of the fish collecting device 7. The water inlet 61 is formed between the door structure 6 and the downstream end of the tailrace tunnel 100 (i.e., the turning position formed at the junction of the tailrace tunnel 100 and the tailrace canal). That is, the included angle formed by the width direction of the water inlet 61 and the width direction L2 of the tailrace canal is an acute angle. The outlet 101 of the tailrace tunnel and the end surface 201 of the tailrace canal are in the same plane.

[0041] The fish accommodation space 11 is provided with a fish collecting box 12. The upper end of the fish collecting box 12 is open. The fish collecting system further includes a lifting device (not shown in the figure) for adjusting the height position of the fish collecting box 12 in the height direction L3. When the fish collecting box 12 is at the lowest height position, the height of the fish flow channel between the water flow outlet and the blocking member 91 is not lower than the height of the top end of the fish collecting box 12. To transfer the fish collected in the fish accommodation space 11, a transfer device of the prior art can be used.

[0042] According to the above solution of the present invention, when it is necessary to collect fish into the fish accommodation space, the fish collecting box at the lowest height position will not affect the swimming of fish from outside the fish accommodation space to the fish accommodation space. After collecting an appropriate number of fish, the lifting device can be used to lift the height of the fish collecting box to collect the fish in the fish accommodation space into the fish collecting box.

[0043] As Figure 5 shown, the fish collecting system includes a flared structure 5. The opening size of the first end of the flared structure 5 is larger than the opening size of the second end of the flared structure 5. The opening of the first end of the flared structure 5 forms the first fish inlet 51, and the opening of the second end of the flared structure 5 forms the second fish inlet 52. The first fish inlet 51 is communicated with the fish accommodation space 11 through the second fish inlet 52. The first fish inlet 51 is located on the upstream side of the second fish inlet 52.

[0044] According to the above solution of the present invention, fish can flow reversely through the larger-sized first end opening (the first fish inlet) and the smaller-sized second end opening (the second fish inlet) in the flared structure in sequence, and then enter the space between the blocking member and the mounting member. The setting of the flared structure and the opening sizes at both ends thereof facilitates the reverse flow of fish into the internal space of the fish collecting system, and the smaller-sized second fish inlet can increase the difficulty for the fish located in the internal space of the fish collecting system to swim outwards.

[0045] A mounting member 92 connected to the flared structure 5 is provided on the water flow channel. The second end opening of the flared structure 5 is located at the position where the flared structure 5 is connected to the mounting member 92. The part of the mounting member 92 located outside the second end opening is used to block the swimming of fish from the downstream side to the upstream side of the mounting member 92 and forms a second water outlet 302. The side wall of the flared structure 5 can be set to allow or not allow water flow through. A third water outlet 303 can also be formed on the side wall of the flared structure 5. The first water outlet 301 is communicated with the first fish inlet 51 serving as the water flow outlet through the second water outlet 302 and the third water outlet 303 in sequence.

[0046] According to the above solution of the present invention, fish located within the fish collection system cannot swim out from the portion of the mounting member outside the opening of the second end, and the portion of the mounting member outside the opening of the second end forms a second water flow port, facilitating the downstream flow of water to the water flow outlet. Additionally, outside the water flow channel formed by the second fish inlet and the first fish inlet, a water flow channel formed by the sequential connection of a first water flow port, a second water flow port, and a third water flow port is provided, which can also provide an additional flow channel for the water flow, thereby reducing the water flow velocity at the fish inlet and the resistance for fish to flow in against the current.

[0047] The width W1 and height H1 of the second fish inlet 52 are 2 to 3 times the body length of the largest fish collection target, ensuring that fish can pass through smoothly horizontally; the width W2 of the first fish inlet 51 is 3 to 4 times the width W1 of the second fish inlet 52, and the height H2 of the first fish inlet 51 is 3 to 4 times the height H1 of the second fish inlet 52, thereby forming an obvious "inlet effect".

[0048] As Figure 4 、 Figure 6 As shown in

[0049] The following further details Embodiment 1 of the present invention.

[0050] Currently, most fish collection facilities use a pumping station water supply system to form a fish attracting flow rate. On the one hand, the fish attracting flow rate created by the submersible pump is extremely limited, and the fish attracting efficiency is low; on the other hand, the construction cost and operation cost of the water supply system are relatively high, and the economy is poor. Directly using the power station tail water for fish collection in the tail water pipe or tail water tunnel of the factory building, the fish attracting water flow velocity is relatively large, it is difficult to form a velocity gradient, and it is impossible to adjust the fish attracting water flow velocity at different water depths, resulting in limited attraction to fish. At the same time, in the current fish collection method using a tail water tank, the water flow directly impacts the fish collection tank, resulting in a large head loss and having a certain impact on the power generation efficiency of the power station.

[0051] Aiming at the deficiencies of the existing fish collection system, the present invention forms a fish attracting flow field structure that can adjust the fish attracting water flow velocity at different water depths and can attract fish at different water depths, while reducing the impact on tail water power generation and efficiently and economically playing the role of the fish collection facility.

[0052] A fish collection system with adjustable flow velocity for different water depths provided by the present invention, as Figures 1 - 5As shown in the figure, it includes: a tail water diversion structure (i.e., the first section 1 of the diversion wall), a partition wall (i.e., the second section 2 of the diversion wall), a guide wall (i.e., the third section 3 of the diversion wall), a fish collecting device 7, a slide rail and a rotary door structure, a control platform 4, a door structure control unit, an escape prevention fence (i.e., a blocking member 91), a hierarchically arranged escape prevention cage (i.e., a flared structure), a retractable fish collecting box, a lifting device, etc. At a position close to the outlet of the tail water tunnel 100, the first section 1 of the diversion wall, the second section 2 of the diversion wall, and the third section 3 of the diversion wall are successively arranged from upstream to downstream.

[0053] The side walls of the tail water diversion structure, the partition wall, the guide wall, and the fish collecting device together form a flow channel. Looking from the top view direction, the tail water diversion structure is arc-shaped and is arranged at a position close to the outlet of the tail water tunnel. One end of the tail water diversion structure is close to the outlet position of the tail water tunnel, and the other end is connected to the partition wall. The tail water diversion structure has a function of splitting the flow, reducing the tail water flow passing through the fish collecting flow channel, and meeting the fish attracting flow requirements during the power generation of a single unit. Looking from the top view direction, the partition wall is linear and parallel to the length direction L1 of the tail water tunnel. Looking from the top view direction, the guide wall is arc-shaped and is connected to the partition wall. The guide wall can guide the main flow of the tail water away from the fish collecting flow channel fish inlet (i.e., the first fish inlet 51), generating an obvious flow velocity gradient at the fish collecting flow channel fish inlet, and fish are more inclined to flow to the position with a smaller flow velocity at this flow velocity gradient position, so as to guide the fish to enter from the fish inlet and achieve fish attraction.

[0054] On the back surface of the tail water diversion structure (i.e., Figure 2 the surface of the first section 1 of the diversion wall facing the rotary door structure 6), multiple layers of slide rails can be arranged along the water depth direction. Each layer of slide rail corresponds to the installation of a rotary door structure, and the door structure can move along the corresponding slide rail. The door structure control unit (not shown in the figure) can be arranged on the back surface of the tail water diversion structure. By adjusting the width of the water inlet 61 of each layer of the door structure through the door structure control unit, the flow rate of the water inlet corresponding to each layer at the height position can be adjusted, so as to adjust the fish attracting flow rate of each layer. The input ends of each door structure control unit are respectively electrically connected to the control platform 4. The control platform 4 and the door structure control unit can be arranged at a position higher than the normal tail water level. The door structure control unit and the control platform 4 can adopt existing control devices. For example, the door structure control unit can adopt a motor control device, and the control platform 4 can adopt a single-chip microcomputer, DSP or PLC controller.

[0055] The known width of the tailrace tunnel (or the width of the tailrace tunnel) is D, the water depth at the tailrace outlet is H, the width of the second fish inlet 52 is W1, the height of the second fish inlet 52 is H1, the width of the first fish inlet 51 is W2, the height of the first fish inlet 51 is H2, the first fish inlet 51 is arranged in N columns, and the porosity of the blocking member 91 (which can be an anti-escape fence) is ku. Then the width em at the position corresponding to the m-th layer of the gate structure in the water inlet 61 approximately satisfies: em = (km × N × Vm × D × H × W1 × (ku × ((W2 × H2) / (W1 × H1)) - ku + 1)) / Q. Where km is the flow velocity change coefficient. When the second fish inlet 52 of the m-th layer is below the elevation of the tailrace tunnel outlet, km can take values from 1 to 1.2. When the second fish inlet 52 of the m-th layer is above the elevation of the tailrace tunnel, km can take values from 1.2 to 1.5. Q is the generating flow rate of the unit. V is the optimal fish attracting flow velocity.

[0056] The fish collecting channel is formed between the blocking member 91, the fish collecting device 7, and the diversion wall.

[0057] As Figure 5 shown, the bellmouth structure 5 (i.e., the anti-escape cage) includes a first guiding structure 5A (forming the main body of the bellmouth structure 5) and a second guiding structure 5B (forming a channel with a fixed height and width) that are connected to each other. One end of the first guiding structure 5A away from the second guiding structure 5B is open to form the first fish inlet 51, and one end of the second guiding structure 5B away from the first guiding structure 5A is open to form the second fish inlet 52.

[0058] Multiple bellmouth structures 5 can be arranged in layers on the mounting member 92. The position where the bellmouth structure 5 is connected to the mounting member 92 forms the fish inlet (i.e., the second fish inlet 52). The first fish inlet 51 of the bellmouth structure 5 forms the water outlet, and the water outlet is located between the fish collecting device 7 and the partition wall.

[0059] In the length direction of the tailrace tunnel, the fish accommodation space 11 (as the fish lounge) is located between the blocking member 91 and the mounting member 92. The fish collecting box 12 can be arranged at the bottom of the fish accommodation space 11. After a certain number of fish gather, the fish collecting box is lifted by the lifting device (not shown in the figure) of the fish collecting device 7 to transfer the fish. The fish accommodation space 11 can avoid the main flow of the water flow channel, so the flow velocity is very low. The fish that enter from the bellmouth structure 5 and swim against the current will not always swim against the main flow of the water flow channel and will enter the fish accommodation space 11 with a lower flow velocity to rest.

[0060] When the unit is a single unit generating electricity, the tailwater flow rate controlled by the first section 1 of the diversion wall can meet the requirements of the fish attracting flow rate. At this time, the width of the water inlet 61 of each layer of the gate structure 6 can be adjusted to make the flow rate at the fish inlet reach the optimal fish attracting flow rate. When multiple units are used to generate electricity at the same time, the tailwater water level flow rate will increase significantly. At this time, the width of the water inlet 61 of each layer of the gate structure can be adjusted by the gate structure control unit to achieve the optimal fish attracting flow rate.

[0061] In the specific application of this embodiment: a hydropower station is a typical high-head dam, which adopts a fish lift system to cross the dam, and the fish collection system of the present invention is used near the tailwater outlet (i.e., near the tailwater tunnel outlet). The power station is a double-machine in one tunnel, with a single unit generating a flow rate of 424m³ / s, and a double unit generating a flow rate of 848m³ / s. According to the statistical fish population and swimming ability test, the main fish collection objects of the present invention are schizothorax and catfish. Schizothorax is mainly distributed in the middle and lower water layers, with a body length of 22.5cm to 41cm, an average body length of 30.9cm, a critical fish-attracting flow rate of 0.89m / s, and a sudden swimming flow rate of 1.26m / s. Therefore, the optimal fish-attracting flow rate range for schizothorax in this project is 0.89m / s to 1.26m / s. Catfish are bottom fish, with a body length of 12cm to 18cm and an average body length of 14cm. The critical swimming speed is 1.35m / s, the breakthrough swimming speed is 2m / s, and the best flow velocity range for attracting fish is 1.35m / s to 2m / s. Therefore, the best flow velocity range for attracting fish for Catfish in this project is 1.35m / s to 2m / s.

[0062] When a single unit is in operation, according to the fish collection system provided by the present invention, the shortest distance between the end of the diversion structure and the end of the tail water tunnel (viewed from the top, the distance between the end of the diversion structure and the end of the tail water tunnel) is 4 m. The width and height of the second fish inlet 52 are 0.6 m and 0.9 m respectively, and the width and height of the first fish inlet 51 are 2 m and 3 m respectively. The porosity of the blocking member 91 (which can be an anti-escape fence) is 0.6, the water depth at the tail water outlet is 27 m, and the gate structure is arranged in 9 layers. The flow velocity change coefficient corresponding to the gate structure at the bottom (i.e., the bottommost 3 layers of the gate structure) is taken as 1.0. Through calculation, the corresponding water flow inlet width for the optimal fish attracting flow velocity can be obtained as 2.9 m to 4.3 m; the flow velocity change coefficient corresponding to the middle layer gate structure (i.e., the middle 3 layers of the gate structure) is taken as 1.2. Through calculation, the corresponding water flow inlet width for the optimal fish attracting flow velocity can be obtained as 2.4 m to 3.4 m; the flow velocity change coefficient of the surface layer gate structure (i.e., the topmost 3 layers of the gate structure) is taken as 1.5. Through calculation, the corresponding water flow inlet width for the optimal fish attracting flow velocity can be obtained as 3.0 m to 4.3 m. By controlling the gate structure to adjust the width of the water flow inlet 61 position corresponding to the surface layer gate structure (i.e., the gate structure in the topmost 3 layers in the height direction), the shortest distance between the end of the gate structure (i.e., the end forming the water flow inlet) and the end of the tail water tunnel is about 3.6 m (taking the value close to the middle position in the calculated width range, the same below); adjusting the width of the water flow inlet 61 position corresponding to the middle layer gate structure (i.e., the gate structure in the 4th to 6th layers in the height direction), the shortest distance between the end of the gate structure (i.e., the end forming the water flow inlet) and the end of the tail water tunnel is about 2.9 m, and adjusting the gate structure below the bottom layer (i.e., the gate structure in the lower 3 layers in the height direction) so that the water flow inlet width is 3.7 m. Through CFD numerical simulation means, the flow field of the fish collection system during the operation of a single unit is calculated and analyzed. The average flow velocity at the bottommost fish inlet is 1.8 m / s, and the average flow velocity at the middle and surface fish inlets is 0.9 m / s. The flow velocities at each layer of fish inlets are within the range of the optimal fish attracting flow velocity, which is basically close to the result calculated by the approximate formula. At the same time, through the squeezing effect of the guide wall on the main flow, the main flow is deflected to the other side, and a significant flow velocity difference is formed between the outlet of the fish collection system and the surrounding flow field, having a good fish attracting flow field. A recirculation flow pattern appears in the fish accommodation space, which is suitable for fish to gather in the rest room, such as Figure 7 , Figure 8 shown. The areas shown in red are the areas with larger flow velocities, and the areas shown in dark blue and blue-green are the areas with smaller flow velocities. On the horizontal section such as Figure 7 and on the cross section such as Figure 8 , the flow velocity on the side of the fish collection system is more appropriate, and the flow velocity on the side of the main tail water is larger, that is, the flow velocities in the water flow channels formed by the fish collection system are all smaller, while a region with a larger flow velocity is formed outside the guide wall. According to the setting of the guide wall, a smaller flow velocity is formed in the water flow channels formed by the fish collection system, which is suitable for fish to enter the water flow channels from the first fish inlet.

[0063] When the unit is operating at full load, the shortest distance from the end of the bottom gate structure to the end of the tailrace tunnel is adjusted to about 1.8 m through the control system, the shortest distance from the end of the middle gate structure to the end of the tailrace tunnel is adjusted to about 1.5 m, and the shortest distance from the end of the surface gate structure to the end of the tailrace tunnel is adjusted to about 1.8 m. At this time, the average flow velocity at the fish inlet of the bottom layer is still about 1.8 m / s, and the average flow velocity at the middle and surface fish inlets is still 0.9 m / s, both of which are within the optimal fish attracting flow velocity range. Corresponding to the head loss of the entire fish collecting system, when a single unit is operating, the fish collecting system increases the head loss by about 0.05 m, and when the unit is operating at full load, the head loss increased by the fish collecting system is 0.21 m. The increase in head loss is small, and the impact on power generation of the power station is small.

[0064] Embodiment 2 The main difference between this Embodiment 2 and Embodiment 1 is that part of the fish collecting system is arranged in the tailrace channel, and the other part is arranged in the tailrace tunnel.

[0065] As Figure 9 shown, the first section 1 of the diversion wall and the gate structure 6 extend into the tailrace tunnel 100, and a water flow inlet 61 is formed between the gate structure 6 and the side wall surface 102 of the tailrace tunnel, so that the water flow inlet 61 is arranged at the outlet 101 of the tailrace tunnel. Other structures in this Embodiment 2 can refer to Embodiment 1. In this embodiment, the width direction of the water flow inlet 61 is parallel to the width direction L2 of the tailrace channel.

[0066] Embodiment 3 The main difference between this Embodiment 3 and Embodiment 1 is that a fish collecting box may not be arranged in the fish accommodation space, but a baffle is used instead. The fish collecting device 7 is also connected with a baffle 71; the baffle 71 has a first state and a second state. Corresponding first guiding grooves 72 and second guiding grooves 73 are respectively formed on the opposite wall surfaces of the fish accommodation space 11, as Figure 10 、 Figure 11 shown. As Figure 10 shown, when the baffle 71 is in the first state, the baffle 71 is located in the first guiding groove 72, and the fish accommodation space 11 is communicated with the water flow channel; as Figure 11 shown, when the baffle 71 is in the second state, the baffle 71 separates the fish accommodation space 11 and the water flow channel, and the baffle 71 extends into the second guiding groove 73.

[0067] Embodiment 4 The main difference between Embodiment 4 of the present invention and Embodiment 1 is that the blocking member can adopt the structure as Figure 12 shown. The difference between the blocking member in this Embodiment 4 and that in Embodiment 1 is that the blocking member 91 can adopt a double-layer structure.

[0068] Embodiment 5 The main difference between Embodiment 5 and Embodiment 1 of the present invention lies in that: the diversion wall includes a second section 2 of the diversion wall and a third section 3 of the diversion wall (not shown in the figure) connected in sequence. The second section 2 of the diversion wall extends downstream from the water inlet position and extends in the length direction L1 of the tailrace tunnel. The third section 3 of the diversion wall extends from the downstream end of the second section 2 of the diversion wall to the water outlet position.

[0069] The fixed end of the gate structure can be installed on the structure opposite to the second section 2 of the diversion wall. If the second section 2 of the diversion wall is arranged in the tailrace canal (similar to the position of the first section 1 of the diversion wall in Embodiment 1), the fixed end of the gate structure can be installed on the fish collecting device 7; if the second section 2 of the diversion wall extends into the tailrace tunnel (similar to the position of the first section 1 of the diversion wall in Embodiment 2), the fixed end of the gate structure can be installed on the side wall surface 102 of the tailrace tunnel.

[0070] It should be noted that the embodiments in this specification are all described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts between the embodiments, reference can be made to each other.

[0071] The above has described the embodiments of the present invention in detail, but the content described is only the preferred embodiments of the present invention and cannot be considered as limiting the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of the present invention should still fall within the scope covered by the present invention. After reading the present invention, various equivalent modifications made by those skilled in the art to the present invention fall within the scope defined by the appended claims of this application. Without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

Claims

1. A fish collection system, the fish collection system having a water flow inlet (61), a water flow outlet, and a water flow channel connected between the water flow inlet (61) and the water flow outlet, characterized in that: A blocking member (91) for blocking fish is provided on the water flow channel; a first water flow opening (301) is formed on the blocking member (91); The water flow inlet (61) is arranged at the outlet (101) of the tailrace tunnel, such that a part of the water flow channel is located in the tailrace tunnel (100), or the water flow inlet (61) is arranged at a position in the tailrace canal (200) close to the outlet (101) of the tailrace tunnel; A fish accommodation space (11) communicating with the water flow channel is formed on one side of the water flow channel; the water flow outlet forms a first fish inlet (51), and a fish flow channel is formed between the first fish inlet (51) and the fish accommodation space (11); the fish flow channel is located on the downstream side of the blocking member (91); The fish collection system further includes a diversion structure extending from the water flow inlet (61) to the downstream of the water flow outlet; the fish accommodation space (11) and the diversion structure are respectively located on both sides of the water flow channel; from the position where the diversion structure forms the water flow outlet to the end of the diversion structure on the downstream side, the distance between the diversion structure and the fish accommodation space (11) in the width direction (L2) of the tailrace canal gradually increases.

2. The fish-aggregating system according to claim 1, wherein: The fish collection system includes a fish collection device (7), the fish collection device (7) extending in the length direction (L1) of the tailrace tunnel, and a groove is formed on the side of the fish collection device (7) facing the water flow channel, and the groove forms the fish accommodation space (11).

3. The fish aggregating system according to claim 1, characterized in that: The diversion structure is a diversion wall, and the diversion wall includes a first section (1) of the diversion wall arranged at the water flow inlet (61); Viewed from the top direction of the fish collection system, from the end of the first section (1) of the diversion wall close to the water flow inlet (61) to the end far from the water flow inlet (61), the distance between the first section (1) of the diversion wall and the fish accommodation space (11) in the width direction (L2) of the tailrace canal gradually increases.

4. The fish-aggregating system according to claim 3, characterized in that: The diversion wall includes a first section (1) of the diversion wall, a second section (2) of the diversion wall, and a third section (3) of the diversion wall connected in sequence; the first section (1) of the diversion wall and the third section (3) of the diversion wall are respectively located on the upstream side and the downstream side of the second section (2) of the diversion wall; The second section (2) of the diversion wall extends in the length direction (L1) of the tailrace tunnel; Viewed from the top direction of the fish collection system, from the end of the third section (3) of the diversion wall close to the water flow inlet (61) to the end far from the water flow inlet (61), the distance between the third section (3) of the diversion wall and the fish accommodation space (11) in the width direction (L2) of the tailrace canal gradually increases; Wherein, the connection between the second section (2) of the diversion wall and the third section (3) of the diversion wall is flush with the water flow outlet, or the connection between the second section (2) of the diversion wall and the third section (3) of the diversion wall is located on the upstream side of the water flow outlet.

5. The fish collection system according to claim 2, characterized in that: The diversion structure is equipped with a gate structure (6) for adjusting the width of the water flow inlet (61); the fish collecting system is arranged in the tailrace (200), the water flow inlet (61) is arranged facing the outlet (101) of the tailrace tunnel, the fish collecting device (7) is arranged close to one side wall surface (202) of the tailrace, the water flow channel and the one side wall surface (202) of the tailrace are respectively located on both sides of the fish collecting device (7), and the water flow inlet (61) is formed between the gate structure (6) and the downstream end of the tailrace tunnel (100); or The diversion structure is equipped with a gate structure (6) for adjusting the width of the water flow inlet (61); at least part of the diversion structure and the gate structure (6) extend into the tailrace tunnel (100), and the water flow inlet (61) is formed between the gate structure (6) and the side wall surface (102) of the tailrace tunnel.

6. The fish collecting system according to claim 2, characterized in that: A fish collecting box (12) is arranged in the fish accommodation space (11), the upper end of the fish collecting box (12) is open, and the fish collecting system further includes a lifting device for adjusting the height position of the fish collecting box (12) in the height direction (L3); when the fish collecting box (12) is at the lowest height position, the height of the fish flow channel between the water flow outlet and the blocking member (91) is not lower than the height of the top of the fish collecting box (12); and / or The fish collecting device (7) is further connected with a baffle (71); the baffle (71) has a first state and a second state; when the baffle (71) is in the first state, the fish accommodation space (11) is communicated with the water flow channel; when the baffle (71) is in the second state, the baffle (71) separates the fish accommodation space (11) from the water flow channel.

7. The fish-aggregating system according to any one of claims 1-6, characterized in that: The fish collecting system includes a flared structure (5); The opening size of the first end of the flared structure (5) is larger than the opening size of the second end of the flared structure (5); The opening of the first end of the flared structure (5) forms the first fish inlet (51), and the opening of the second end of the flared structure (5) forms the second fish inlet (52); The first fish inlet (51) is communicated with the fish accommodation space (11) through the second fish inlet (52); The first fish inlet (51) is located on the downstream side of the second fish inlet (52).

8. The fish-aggregating system according to claim 7, wherein: An installation member (92) connected to the flared structure (5) is arranged on the water flow channel; The opening of the second end of the flared structure (5) is located at the position where the flared structure (5) is connected to the installation member (92); The part of the installation member (92) located outside the second end opening is used to block fish and forms a second water flow port (302); a third water flow port (303) is formed on the side wall of the flared structure (5).

9. The fish aggregating system according to claim 7, wherein: The width and height of the second fish inlet (52) are 2 to 3 times the body length of the largest fish collecting object; the width of the first fish inlet (51) is 3 to 4 times the width of the second fish inlet (52), and the height of the first fish inlet (51) is 3 to 4 times the height of the second fish inlet (52).

10. The fish-aggregating system according to claim 7, characterized in that: The drainage structure is installed with M gate structures (6) for adjusting the width of the water inlet (61) and M×N second fish inlets (52); the M gate structures (6) are arranged in sequence in the height direction (L3) to form an M-layer structure, and the gate structure control units corresponding to the respective gate structures (6) are independently arranged; the respective second fish inlets (52) form an overall structure with M layers and N columns; M≥2, N≥1; in the overall structure, the second fish inlet (52) located on the m-th layer is at the same height as the m-th gate structure (6), 1≤m≤M; In the overall structure, the respective second fish inlets (52) located on the same layer are arranged in sequence in the width direction (L2) of the tailrace; The width of the position in the water inlet (61) corresponding to the m-th layer gate structure (6) is: e_m=(k_m×N×V_m×D×H×W1×(ku×((W2×H2) / (W1×H1))-ku+1)) / Q; Where: k_m is the flow velocity change coefficient corresponding to the height position of the second fish inlet (52) on the m-th layer; V_m is the optimal fish attracting flow velocity corresponding to the height position of the second fish inlet (52) on the m-th layer; D is the width of the tailwater tunnel (100); H is the water depth at the outlet (101) of the tailwater tunnel; Q is the power generation tailwater flow; W1 is the width of the second fish inlet (52), H1 is the height of the second fish inlet (52), W2 is the width of the first fish inlet (51), H2 is the height of the first fish inlet (51), and ku is the porosity of the blocking member (91); When the height position of the first fish inlet (51) on the m-th layer is not higher than the elevation of the outlet (101) of the tailwater tunnel, the value range of k_m is [1, 1.2], and when the height position of the first fish inlet (51) on the m-th layer is higher than the elevation of the outlet (101) of the tailwater tunnel, the value range of k_m is [1.2, 1.5].

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