A flow velocity measuring device for turbine efficiency testing

Abstract

This utility model belongs to the technical field of measuring equipment, and specifically relates to a flow velocity measuring device for testing the efficiency of a water turbine. It includes a fixed frame and flow meters; the fixed frame is composed of multiple rectangular frames spliced ​​together, with multiple support plates and multiple support rods arranged alternately within the frames; multiple flow meters are arranged in an array on multiple support plates, with the detection end of the flow meters facing the water-facing side of the fixed frame. In this flow velocity measuring device, the fixed frame is composed of multiple rectangular frames spliced ​​together, and the multiple flow meter arrays are set on multiple support plates within the frames. During transportation, multiple smaller frames can be directly transported to the designated location, and then during the installation of the flow velocity measuring device, the multiple frames are assembled into the fixed frame and easily hoisted into the slot, thereby reducing the difficulty of transporting and installing the flow velocity measuring device.

Description

Technical Field

[0001] This utility model belongs to the field of measurement equipment technology, and specifically relates to a flow velocity measuring device for water turbine efficiency testing. Background Technology

[0002] After the hydropower station units are put into operation, the water flow rate of the hydropower station needs to be tested to verify the design indicators of the hydropower station units (the efficiency of the water turbine). The water flow rate can be calculated by the catchment area and the water flow velocity.

[0003] In existing technologies, water flow velocity measurements in hydropower stations are generally conducted within the tailrace channel or pressure pipe. However, some hydropower stations use axial-flow turbine units, and the tailrace gates are opened and closed using fixed winches. Since the tailrace gates are immovable and there are no pressure pipes available on site, traditional tailrace or pressure pipe measurement methods are not feasible. Therefore, it is necessary to measure the water flow velocity at the gate slot of the intake maintenance gate.

[0004] However, the cross-sectional area of ​​this location (the door slot of the water inlet inspection door) is relatively large, and the weight of the installed measuring device and the area occupied during transportation are both very large. For example, the Chinese invention patent application with announcement number CN112147362A and title "A Water Conservancy Monitoring Device" has a frame that is an integral whole, making the transportation and installation of this type of water conservancy monitoring device extremely difficult. Furthermore, the overall hoisting scheme for this type of water conservancy monitoring device is time-consuming and has high construction costs. Utility Model Content

[0005] This invention provides a flow velocity measuring device for testing the efficiency of water turbines, thereby solving the technical problem that the existing water conservancy monitoring devices are heavy and occupy a large area during transportation, resulting in high difficulty in transportation and installation.

[0006] This utility model is achieved through the following technical solution:

[0007] A flow velocity measuring device for testing the efficiency of a water turbine includes a fixed frame and a flow velocity meter;

[0008] The fixed frame is composed of multiple rectangular frames spliced ​​together in a vertical direction. Multiple support plates and multiple support rods are set in the frame. The multiple support plates and multiple support rods are arranged in an alternating manner. The ends of the support plates and the ends of the support rods are connected to the inner sidewall of the frame.

[0009] There are multiple flow meters, and multiple flow meter arrays are arranged on multiple support plates, with the detection end of the flow meter facing the water-facing side of the fixed frame.

[0010] To better realize this utility model, the above structure is further optimized by providing support blocks that match the door slot on both sides of the frame.

[0011] To better realize this utility model, further optimization is made to the above structure. The frame is provided with multiple bundled steel bars, and the positions of the multiple bundled steel bars correspond one-to-one with the positions of the multiple support plates.

[0012] The current meter's wires are bound or wrapped with tape around the reinforcing steel bar.

[0013] To better realize this utility model, the above structure is further optimized, and the distance between two adjacent flow meters is equal to the diameter of the flow meter's detection range.

[0014] To better realize this utility model, the above structure is further optimized by providing multiple mounting plates on the support plate;

[0015] Multiple mounting plates are arranged at equal intervals along the long axis of the support plate;

[0016] Multiple flow meters are mounted one-to-one on multiple mounting plates.

[0017] To better realize this utility model, the above structure is further optimized, and multiple support plates are arranged in the frame at equal intervals along the vertical direction, and the long axis of the support plates is parallel to the horizontal line.

[0018] Multiple support rods are arranged horizontally at equal intervals in the frame, with the long axis of the support rods perpendicular to the horizontal line, and the support rods pass through all support plates.

[0019] To better realize this utility model, further optimizations are made to the above structure. The frame of the fixed frame includes an upper frame, a lower frame, and two sets of side frames. The upper frame, the lower frame, and the two sets of side frames are all made of I-beams. A reinforcing rod is provided on the upper frame to increase the strength of the upper frame.

[0020] To better realize this utility model, further optimizations are made to the above structure. The reinforcing rod is made of I-beams, and the size of the reinforcing rod is equal to the size of the upper frame. The reinforcing rod is located on the side of the upper frame away from the lower frame, and the same side of the two wing plates of the reinforcing rod is fixedly connected to the same side of the two wing plates of the upper frame, respectively.

[0021] To better realize this utility model, further optimizations are made to the above structure. Limiting feet are provided on both the upper and lower frame, and the limiting feet are located on the water-facing side of the fixed frame.

[0022] To better realize this utility model, the above structure is further optimized by providing a lifting lug on the upper frame.

[0023] Compared with the prior art, this utility model has the following advantages:

[0024] In the flow velocity measuring device provided by this utility model, the fixed frame is composed of multiple rectangular frames spliced ​​together, and multiple flow velocity meter arrays are set on multiple support plates in the frame. During transportation, multiple smaller frames can be directly transported to the designated location. Then, during the installation of the flow velocity measuring device, the multiple frames are assembled into a fixed frame and easily hoisted into the door slot, thereby reducing the difficulty of transporting and installing the flow velocity measuring device. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the flow velocity measuring device for testing the efficiency of a water turbine, according to this utility model.

[0027] Figure 2 yes Figure 1 A magnified view of part A in the middle.

[0028] Figure 3 yes Figure 1 A magnified view of part B in the middle.

[0029] Figure 4 This is a front view of a flow velocity measuring device for testing the efficiency of a water turbine, according to this utility model.

[0030] Figure 5 This is a schematic diagram of the top frame structure of a flow velocity measuring device for testing the efficiency of a water turbine, according to this utility model.

[0031] Figure 6 This is a schematic diagram of the middle frame structure in a flow velocity measuring device for testing the efficiency of a water turbine, according to this utility model.

[0032] Figure 7 This is a schematic diagram of the bottom frame structure of a flow velocity measuring device for testing the efficiency of a water turbine, according to this utility model.

[0033] In the picture:

[0034] 1. Fixed frame; 11. Frame; 111. Support plate; 112. Support block; 113. Reinforcing bar; 114. Mounting plate; 115. Support rod; 12. Top frame; 13. Bottom frame; 14. Side frame; 15. Reinforcing rod; 16. Limiting leg; 17. Lifting lug;

[0035] 2. Flow meter. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0037] In the description of this utility model, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0038] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0039] In the embodiments of this application, such as Figures 1 to 7 As shown, this flow velocity measuring device can be used for efficiency testing of water turbines, mainly for verifying the design parameters of hydropower station units, that is, for detecting the efficiency of water turbines. The flow velocity measuring device includes a fixed frame 1 and a flow meter 2. (See attached image.) Figures 1 to 4 ;in,

[0040] The fixed frame 1 is composed of multiple rectangular frames 11 sequentially spliced ​​along the vertical direction. Multiple support plates 111 and multiple support rods 115 are provided in the frame 11. The multiple support plates 111 and multiple support rods 115 are arranged alternately. In this embodiment, the support plates 111 are arranged along the long axis of the frame 11, and the support rods 115 are arranged along the short axis of the frame. The ends of the support plates 111 and the ends of the support rods 115 are connected to the inner sidewall of the frame 11 to make the structure of the frame 11 more stable.

[0041] There are multiple flow meters 2, and multiple flow meters 2 are arranged in an array on multiple support plates 111, with the detection end of the flow meter 2 facing the water-facing side of the fixed frame 1.

[0042] In this embodiment, there are three frames 11, namely the bottom frame, the middle frame, and the top frame, respectively. See [link / reference needed]. Figures 4 to 7 The bottom frame, middle frame and top frame can be fabricated in the factory or on the construction site. After fabrication, they are transported by the manufacturer to the designated location by a transport vehicle. During the installation of the flow velocity measuring device, the bottom frame, middle frame and top frame are assembled (assembled into fixed frame 1). After assembly, it is hoisted into the door slot for water flow velocity measurement.

[0043] Specifically, a 100T truck crane is used to lift the bottom frame to the location of the inspection door, and multiple flow meters 2 are installed on multiple support plates 111 in the bottom frame. After the flow meters 2 are installed, the bottom frame is lifted to the opening of the inspection door, and multiple I-beams are used to hold the bottom frame in place at the opening (the axis of the opening is perpendicular to the horizontal plane). That is, a part of the bottom frame is placed downward into the opening, and the other part is located outside the opening. Multiple I-beams are passed through the bottom frame, so that the two ends of the I-beams are respectively supported on both sides of the opening, and the bottom frame is fixed by using the I-beams. At this time, the lifting end of the truck crane is removed from the bottom frame.

[0044] Subsequently, a truck crane is used to lift the middle frame to the location of the inspection door, and multiple flow meters 2 are installed on multiple support plates 111 in the middle frame. After the flow meters 2 are installed, the middle frame is lifted to the opening of the inspection door, and the position of the middle frame is finely adjusted so that the middle frame and the bottom frame are in the same vertical plane or close to the same plane. Then, the middle frame is slowly lowered so that the bottom of the middle frame contacts the top of the bottom frame, and then the middle frame and the bottom frame are fixed. The middle frame and the bottom frame can be fixed by welding or bolt connection. In this embodiment, the middle frame and the bottom frame are fixed by bolts.

[0045] After the middle and bottom frames are fixed, they are slightly lifted, and the multiple I-beams fixing the bottom frame are removed. Then, the middle frame is lowered into the hole until the entire bottom frame is inside the hole, with a portion of the middle frame inserted into the hole and the other portion outside. Subsequently, multiple I-beams are passed through the middle frame, with both ends of the I-beams positioned on either side of the hole to support and fix the middle frame. At this point, the lifting end of the truck crane is removed from the middle frame.

[0046] Finally, the top frame is lifted to the location of the inspection door using a truck crane, and multiple flow meters 2 are installed on multiple support plates 111 in the top frame. After the flow meters 2 are installed, the top frame is lifted to the opening of the inspection door, and the position of the top frame is finely adjusted so that the top frame and the middle frame are in the same vertical plane or close to the same plane. Then, the middle frame is slowly lowered so that the bottom of the top frame contacts the top of the middle frame. The top frame and the middle frame are then fixed. The top frame and the middle frame can be fixed by welding or bolting. In this embodiment, the top frame and the middle frame are fixed by bolts.

[0047] After the top and middle frames are fixed, a fixed frame 1 is formed. The fixed frame 1 is slightly lifted, and multiple I-beams of the fixed middle frame are removed. Then, the fixed frame 1 is lowered into the orifice until it is completely inside, thus completing the installation of the flow velocity measuring device.

[0048] During transportation, multiple small frames 11 can be directly transported to the designated location. Then, during the installation of the flow velocity measuring device, the multiple frames 11 can be assembled into a fixed frame 1 and easily locked into the door slot, thereby reducing the difficulty of transporting and installing the flow velocity measuring device.

[0049] In some embodiments, support blocks 112 matching the door groove are provided on both sides of the frame 11 described above. See [reference needed]. Figures 5 to 7 The major axis of the support block 112 is perpendicular to the plane in which the frame 11 is located;

[0050] After the installation of the fixed frame 1 is completed, the fixed frame 1 is securely fixed in the door groove by the support block 112, so as to avoid the fixed frame 1 from shaking in the door groove of the maintenance door during use, which would affect the detection results, thereby improving the detection accuracy of the flow rate measuring device.

[0051] Preferably, the length of the support block 112 is 100mm smaller than the width of the door groove, so that the support block 112 can be easily inserted into the door groove.

[0052] In some embodiments, the frame 11 described above is provided with a plurality of wire-reinforcing bars 113, and the positions of the plurality of wire-reinforcing bars 113 correspond one-to-one with the positions of the plurality of support plates 111.

[0053] The wires of the current meter 2 are bound or wrapped with tape to the wire harness 113 to ensure that the wires of the current meter 2 will not be damaged by the water flow during use; in this embodiment, the wire harness 113 is fixed in the frame 11 by welding.

[0054] In some embodiments, the distance between two adjacent flowmeters 2 is equal to the diameter of the detection range of the flowmeter 2, so as to avoid the situation where the detection ranges of two adjacent flowmeters 2 overlap and affect the detection results, thereby further improving the detection accuracy of the flow rate measuring device.

[0055] In some embodiments, the support plate 111 described above is provided with a plurality of mounting plates 114, see [reference]. Figure 3 ;in,

[0056] Multiple mounting plates 114 are arranged at equal intervals along the long axis of the support plate 111;

[0057] Multiple flow meters 2 are mounted one-to-one on multiple mounting plates 114. In this embodiment, the flow meters 2 are fixed to the mounting plates 114 with bolts to make the installation of the flow meters 2 more convenient and to reduce damage to the support plate 111, so as to make the structure of the flow measurement device more stable.

[0058] In some embodiments, a plurality of support plates 111 are arranged in the frame 11 at equal intervals along the vertical direction, and the major axis of the support plates 111 is parallel to the horizontal line.

[0059] Multiple support rods 115 are arranged at equal intervals along the horizontal direction in the frame 11, and the long axis of the support rods 115 is perpendicular to the horizontal line. The support rods 115 pass through all the support plates 111. In this embodiment, the support plates 111 are made of 16mm thick Q235 steel plates, and the support rods 115 are made of DN65 (76.1mm in diameter) Q235 steel pipes. The positions where the support rods 115 and the support plates 111 intersect are fixed by welding, making the structure of the flow rate measuring device more stable.

[0060] In some embodiments, the frame of the fixed frame 1 described above includes an upper frame 12, a lower frame 13, and two sets of side frames 14. See [link to previous document]. Figure 4 The upper frame 12, lower frame 13 and two sets of side frames 14 are all made of I-beams. The upper frame 12 is provided with reinforcing rods 15 to increase strength, so as to further improve the structural strength of the flow rate measuring device.

[0061] Preferred, see Figure 2 The aforementioned reinforcing rod 15 is made of I-beams, and the size of the reinforcing rod 15 is equal to the size of the upper frame 12. The reinforcing rod 15 is located on the side of the upper frame 12 that is away from the lower frame 13. The same side of the two wing plates of the reinforcing rod 15 is fixedly connected to the same side of the two wing plates of the upper frame 12 respectively.

[0062] In some embodiments, limit feet 16 are provided on both the upper frame 12 and the lower frame 13. See Figure 2 , Figure 5 and Figure 7The plane of the limiting support 16 is perpendicular to the plane of the fixed frame 1. The limiting support 16 can support the fixed frame 1 and, together with the opening of the inspection door and the base plate of the inspection door installation position, restrict the position of the fixed frame 1 to prevent the fixed frame 1 from tilting to one side, so as to make the installation of the fixed frame 1 more stable and ensure the detection accuracy of the flow rate measuring device.

[0063] Preferably, the aforementioned limiting support 16 is located on the water-facing side of the fixed frame 1.

[0064] In some embodiments, a lifting lug 17 is provided on the upper frame 12 to make it easier to hoist the fixed frame 1.

[0065] To better illustrate the practical effect of the flow velocity measuring device, this embodiment uses a hydropower station as an example to specifically describe the structure and effect of the flow velocity measuring device, as follows:

[0066] Based on the dimensions (11300×13140mm) of the inlet inspection door frame and measurement requirements, a modular fixed frame 1 was designed, with the following core parameters:

[0067] Overall dimensions of fixed frame 1: 12600×13400×1500mm (length×width×height);

[0068] Main structure:

[0069] The support plate 111 is made of 16mm steel plate, and there are 12 of them;

[0070] The support rod 115 is a DN65 steel pipe (76.1mm in diameter), and there are 5 of them;

[0071] The frame (top frame 12, bottom frame 13 and two sets of side frames 14) is made of 300×150×10mm I-beams;

[0072] The reinforcing bar 15 is an I-beam measuring 300×150×10mm;

[0073] Mounting plate 114 is a 50×150×16mm steel plate; there are 144 mounting plates 114 and 144 flow meters 2.

[0074] The support block 112 is a 150mm long I-beam; there are 18 support blocks 112 in total, and the 18 support blocks 112 are evenly distributed on both sides of the three-section frame 11.

[0075] Design basis:

[0076] Matching design flow rate of 258 m³ / s;

[0077] Safety principle: The effect of buoyancy is ignored in the calculation, and the load is taken as the value of the most unfavorable working condition. The impact force of the water flow on the fixed frame 1 and the flow meter 2 can be calculated as follows: ; In the formula: F is the impact force of the water flow; ρ is the density of water (1000 kg / m³). 3 A is the cross-sectional area of ​​the load-bearing structure; V is the water flow velocity. in: ; V = Q / S (V is the flow velocity; Q is the flow rate; S is the cross-sectional area at that point) = 258 / (11.3 × 13.14) = 1.7375 m / s; In summary: ;

[0078] Therefore, the impact force of the water flow on the fixed frame 1 is 24.65kN.

[0079] Considering that the fixed frame 1 needs to be used underwater, and the water flow has the characteristic of pulse impact, in order to ensure the safe use of the flow velocity measuring device, the water flow impact force is adjusted to 2.5 times the theoretical value. Therefore, the water flow impact force on the fixed frame 1 and the flow velocity meter 2 will be calculated as 26.15×2.5=65.375kN.

[0080] Material selection:

[0081] Because the fixed frame 1 and the flow meter 2 experience significant impact at this location, and considering the calculated water flow impact force, the on-site material should be a standard Q235 (300×150mm) H-beam. Taking into account the special working conditions, all impact forces at this location are borne by the H-beams of the frame, meaning the bending compressive strength of these H-beams is: ; Where: P 边框 F represents pressure; S represents force. 边框 The area under stress;

[0082] The design bending strength of Q235 (300×150mm) I-beams is: ; in: For bending strength; The yield strength of the material (235 MPa for Q235 steel); This is the material partial factor (see Table 1, value is 1.5);

[0083] Table 1. Parameters of I-beams: .

[0084] because: Therefore, Q235 (300×150mm) I-beams are used to meet the requirements of this application.

[0085] The aforementioned support plate 111 is made of Q235×16mm steel plate, and the support rod 115 is made of DN65 steel pipe made of Q235. The support rod 115 mainly supports the long-span support plate 111 and only bears a small water flow impact force. The force at this point is mainly borne by the support plate 111, and only the force on the support plate 111 is considered here.

[0086] Assuming that all the impact force of the water flow is borne by the support plate 111 (65.375KN), and that the support plates 111 are supported by 5 rows of support rods 115, the total span of the support plates 111 is 12.539 meters, which is divided into 6 segments by the 5 rows of support rods 115, each segment having a span of 2089.9 mm (supported by two side frames 14 at both ends), the 12 support plates 111 are divided into 72 small segments;

[0087] Because the flow meter 2 needs to be installed, the width of the support plate 111 is designed to be 300mm, and the calculation is performed using a concentrated load at mid-span: ; in: This is the maximum load force; L is the bending strength (for Q235, see Table 2 in GB 50017-2017.4.4.1); W is the material span; and W is the section modulus (calculated as follows: (where b is the material width and t is the material thickness)

[0088] Table 2 Design strength parameters for steel (N / mm²) 2 ): .

[0089] Therefore, the maximum load that the support plate 111 can withstand is: ; ; ;

[0090] The 72 supporting plates 111, each with a span of 2089.9 mm, collectively bear the impact force of the water flow, which is 65.375 kN. Therefore: ;

[0091] The support plate 111 can withstand the impact of water flow.

[0092] Strength calculation of weld seam 115 for support rod:

[0093] The support rod 115 mainly bears the weight of the support plate 111 and the weight of the flow meter 2. Considering the pulse impact of the water flow at this location, the weight of both is taken as 2.5 times the safety factor.

[0094] According to on-site measurements, each flow meter 2 weighs 1 kg. Three flow meters 2 are installed at intervals on each small section of support plate 111. Here, only the weld seam of the support rod 115 bearing the greatest force in this flow measurement device is calculated (the remaining parts are welded according to the standards here). The part of the support rod 115 bearing the greatest force consists of: six flow meters 2 and two small sections of support plate 111 (4200mm × 300mm × 16mm) connected to the support rod 115. Therefore, the maximum gravity borne by the weld seam at this location (the connection between support plate 111 and support rod 115) is: ; ; Where: m is the mass of the object ( (where v is the material density; v is the volume); and g is the acceleration due to gravity, taken as 9.8 m / s². 2 ;

[0095] According to GB / T 908-2019, the density of Q235 steel plate is 7850 kg / m³. 3 Therefore, from the above formula, we can obtain: ; F 重 =1609.7088N≈1.6kN; The safety factor at this location is 2.5, therefore the calculated load-bearing capacity of the weld at this location is 4000N.

[0096] Design formula based on minimum solder joint size: ; Where: F is the design bearing capacity, and in this case, it is F. 重 ; The weld length is given here, as the weld is made around a 73.1mm diameter steel pipe surrounding the support rod 115. ; The design strength of the fillet weld is 215 (see Table 3 of this document according to GB 50017-2017). The design strength of the Q235 steel weld is 215. The 0.7 in this formula is a constant and can be referenced from the given value in GB 50017-2017 11.2.2.

[0097] In summary, the minimum solder joint size at this location should be: ;

[0098] To facilitate on-site welding, a 12mm weld was used. According to the above calculations, this weld can meet the usage requirements of the fixed frame 1.

[0099] Table 3 Weld strength parameters (N / mm) 2 ) .

[0100] After welding is completed, the mounting plate 114 needs to be welded with a weld leg of 12mm. The lifting lug 17 is welded on the upper frame 12. The lifting lug 17 should be subjected to weld penetration test (PT) to ensure that there are no crack defects.

[0101] Bolt calculation:

[0102] Since the fixed frame 1 is heavy and inconvenient to hoist to the site, this embodiment adopts a three-section (three frames 11) design. The adjacent two frames 11 are connected by bolts. The number and grade of bolts required are calculated.

[0103] Assuming that the bolt at this location needs to bear the full impact force of the frame 11 from two directions simultaneously (the water flow has a pulse effect), that is, it is subjected to shear force from two directions, that is, the resultant force is 65.375×2=130.75kN. It is expected that an 8.8 grade M24×70 bolt will be used at this location. First, calculate the bearing capacity of a single bolt.

[0104] The formula for the design value of bolt shear capacity is: ; in: d is the number of shear surfaces of the bolt (1 in this case); d is the nominal diameter of the bolt. The design value for bolt shear strength (see JGJ 82-2011 3.2, see Table 4 of this document, the value is 250 N / mm²) 2 )

[0105] Therefore, the shear force that a single bolt can withstand is: ;

[0106] Each row is connected with 10 bolts, which can withstand a shear force of 113.04×10=1130.4kN>130.75kN, meaning that each row of 10 bolts can meet the usage requirements.

[0107] Table 4 Calculated strength values ​​of bearing-type high-strength bolted connections (N / mm²) 2 ) .

[0108] The fixed frame 1 was fabricated using a metal structure processing platform on the construction site. During the fabrication of the fixed frame 1, the following processes were strictly followed in accordance with the design drawings and structural strength calculation requirements to ensure the overall structural strength, stability, and ease of installation:

[0109] 1. Welding process: All welding is carried out by manual electric arc welding. The weld leg height of the weld in the critical stress parts is not less than 10mm, and the weld leg of the mounting plate 114 is not less than 12mm. In addition, PT (penetration testing) is carried out at important nodes such as lifting lug 17 to ensure the reliability of welding for underwater use.

[0110] 2. Structural assembly optimization:

[0111] The connection between the support rod 115 and the support plate 111 is achieved by the support rod 115 passing through the support plate 111, rather than being directly welded to the surface of the support plate 111, which effectively reduces welding deformation and improves local load-bearing strength.

[0112] 3. Bolt connection process:

[0113] All connecting sections use high-strength 8.8 grade M24 bolts with a connection hole position error of ≤1mm to ensure the integrity of the segmented assembly. During on-site construction, the tightening torque is controlled at 660N·m. After all bolts are connected, a second inspection is carried out to eliminate the risk of loosening.

[0114] 4. Stranded steel reinforcement 113:

[0115] To ensure that the wires of the current meter 2 are not damaged by the water flow underwater, the wire-binding steel bar 113 needs to be welded to the fixed frame 1 to facilitate the fixation of the wires. The wire-binding steel bar 113 can be welded by hand.

[0116] The fixed frame 1 adopts a three-section design, and the hoisting and transportation can be completed in three separate transfers.

[0117] The top-level frame is the heaviest of the three sections, so the hoisting plan is designed based on it. The top-level frame consists of 5 support plates 111, two 12.6m long H-beams (upper frame 12 and reinforcing rod 15), two 5m long H-beam combinations (part of the side frame 14), 5 5m long support rods 115, and 6 support blocks 112. Therefore, the total weight of the top-level frame is: ;

[0118] The weight per meter of the I-beam (JIS G3192-2008 Table 10-1, see Table 5 of this article, is 76.8 kg / m), and the theoretical weight of the support rod 115 is shown in Table 6 of this article, here it is 7.88 kg / m. The total length of the support block 112 is 9m. Therefore, the total weight of the top-level frame is: ;

[0119] Taking into account the weight of welds, bolts, and other accessories, the final calculation is based on 4.4t.

[0120] Table 5 Theoretical Weight of I-Beams:

[0121] .

[0122] Table 6 Theoretical Weight Table for Welded Steel Pipes: .

[0123] Selection of truck cranes:

[0124] Based on the weight of the single frame 11 calculated above, a 25T truck crane is sufficient to meet the transportation requirements. In this embodiment, a 100T truck crane is selected.

[0125] Transportation vehicle selection:

[0126] Cargo parameters:

[0127] Dimensions: 12.6m (length) × 5.23m (width) × 1.5m (height);

[0128] Weight: 4.4 tons;

[0129] Vehicle requirements:

[0130] Vehicle type: 13-meter low flatbed semi-trailer (cargo platform length 13m, width 3m, load capacity ≥ 40 tons).

[0131] Number of axles: 3 axles (13 tons per axle, total load 39 tons > 32 tons).

[0132] (1) Lifting system configuration:

[0133] Truck crane selection and positioning:

[0134] 100T truck crane: parked on the concrete support between Units 2 and 3, with a boom extension of 30.7m (counterweight 6.5T), working radius of 14m, and rated lifting capacity of 11T;

[0135] Safety control of lifting gear:

[0136] The wire rope / shackle has a rated load of ≥10T. Before use, a comprehensive inspection should be conducted to check for wear and deformation.

[0137] Four windproof cables are installed at the four corners of frame 11 to prevent swaying in the air.

[0138] (2) Precise positioning within the door slot:

[0139] Anti-detachment design: Frame 11 and the door motor pulley block are rigidly locked together by a steel connecting plate to avoid the risk of detachment;

[0140] Layered locking: Three 200# I-beams are evenly distributed along the door slot for support, and a fall-prevention net is installed throughout the locking process;

[0141] Fine-tuning positioning: After positioning, use a hydraulic jack to adjust the level (±2mm), and tighten the bolts after aligning the bolt holes (M24 bolt torque value 330N·m).

[0142] After the measurement task is completed, frame 11 must be safely dismantled according to the standardized reverse procedure. The key steps are as follows:

[0143] 1. Disassembly system execution:

[0144] Lifting consistency: The same configuration as the 100T truck crane (30.7m boom / 6.5T counterweight / 14m working radius) will be used.

[0145] Segmented dismantling: Modular dismantling in reverse order of installation; four windproof cables are installed at the four corners of frame 11 to suppress swaying.

[0146] Connection disassembly: Before disassembly, verify the locking status of the steel connecting plate and use auxiliary lifting points to prevent it from falling off.

[0147] 2. Transportation and On-site Management:

[0148] Segmented fixing: The 11 segments of the frame are double-locked to the 13-meter flatbed truck using nylon straps and anti-slip wedges;

[0149] Route monitoring: Dedicated personnel will guide passengers to avoid obstacles on the dam crest, and a warning zone will be set up with a hoisting radius of 15m;

[0150] Foundation verification: The bearing capacity of the foundation in the crane station area is ≥150kPa.

[0151] In summary, this flow velocity measuring device has the following advantages:

[0152] 1. Modular and efficient construction system:

[0153] The three-section detachable frame 11 (maximum single section size 12.6m×5.23m×1.8m, weight 4.4t) is compatible with conventional transportation equipment (13-meter flatbed truck) and hoisting machinery (100T crane) to solve the problem of transporting oversized components;

[0154] On-site, high-strength assembly was achieved through high-strength bolt connections (8.8 grade M24 bolts, 10 bolts per row, tightening torque 330 N·m), which shortened the construction period by more than 50% compared with the traditional overall hoisting solution.

[0155] 2. Multi-dimensional security design:

[0156] Structural reliability: The long-term stability of frame 11 under underwater pulse load is ensured by calculating the impact force of water flow and applying a safety factor of 2.5.

[0157] 3. Process controllability:

[0158] The critical welds were welded manually, with a weld leg height of ≥10mm. The 17 welds on the lifting lugs of the top frame passed the PT test.

[0159] The support rod 115 passes through the connection structure of the support plate 111, avoiding weak links caused by direct welding and effectively improving the local load-bearing strength.

[0160] Local reinforcement measures are added to key nodes to reduce welding deformation and improve overall rigidity;

[0161] By comprehensively applying the structure of the support rod 115 passing through the support plate 111 and optimizing the welding process, the problems of easy deformation and insufficient strength of large underwater measuring equipment are improved.

[0162] 4. Optimize overall process costs:

[0163] Material economy: Using conventional Q235 steel (I-beams / steel plates / steel pipes) on site, the support rod 115 passes through the support plate 111, which effectively reduces the complexity of the welding process. Overall, the cost is reduced by more than 30% compared with special materials and traditional solutions.

[0164] Equipment versatility: The structural dimensions and weight are compatible with standard transport vehicles and truck cranes, avoiding the need for customized equipment.

[0165] The device is reusable: the three-section frame 11 structure supports disassembly and recycling, extending its lifespan to multiple projects for reuse.

[0166] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.

Claims

1. A flow velocity measuring device for testing the efficiency of a water turbine, characterized in that: Includes a fixed frame (1) and a flow meter (2); The fixed frame (1) is formed by splicing multiple rectangular frames (11) in a vertical direction. Multiple support plates (111) and multiple support rods (115) are provided in the frame (11). The multiple support plates (111) and multiple support rods (115) are arranged alternately. The ends of the support plates (111) and the ends of the support rods (115) are connected to the inner wall of the frame (11). There are multiple flow meters (2), and multiple flow meters (2) are arranged in an array on multiple support plates (111), with the detection end of the flow meter (2) facing the water-facing side of the fixed frame (1).

2. The flow velocity measuring device for turbine efficiency testing according to claim 1, characterized in that: Both sides of the frame (11) are provided with support blocks (112) that match the door slot.

3. The flow velocity measuring device for turbine efficiency testing according to claim 1, characterized in that: The frame (11) is provided with multiple bundled steel bars (113), and the positions of the multiple bundled steel bars (113) correspond one-to-one with the positions of the multiple support plates (111); The wires of the flow meter (2) are bound or wrapped with tape on the wire reinforcement bar (113).

4. The flow velocity measuring device for turbine efficiency testing according to claim 1, characterized in that: The distance between two adjacent flowmeters (2) is equal to the diameter of the detection range of the flowmeter (2).

5. The flow velocity measuring device for turbine efficiency testing according to claim 1, characterized in that: The support plate (111) is provided with a plurality of mounting plates (114). Multiple mounting plates (114) are arranged at equal intervals along the long axis of the support plate (111); Multiple flow meters (2) are mounted one-to-one on multiple mounting plates (114).

6. The flow velocity measuring device for turbine efficiency testing according to claim 1, characterized in that: Multiple support plates (111) are arranged vertically at equal intervals in the frame (11), and the major axis of the support plates (111) is parallel to the horizontal line; Multiple support rods (115) are arranged at equal intervals in the horizontal direction in the frame (11), and the long axis of the support rod (115) is perpendicular to the horizontal line. The support rod (115) passes through all support plates (111).

7. The flow velocity measuring device for turbine efficiency testing according to any one of claims 1 to 6, characterized in that: The frame of the fixed frame (1) includes an upper frame (12), a lower frame (13) and two sets of side frames (14). The upper frame (12), the lower frame (13) and the two sets of side frames (14) are all made of I-beams. The upper frame (12) is provided with a reinforcing rod (15) to increase the strength of the upper frame (12).

8. The flow velocity measuring device for turbine efficiency testing according to claim 7, characterized in that: The reinforcing rod (15) is made of I-beams, and the size of the reinforcing rod (15) is equal to the size of the upper frame (12). The reinforcing rod (15) is located on the side of the upper frame (12) away from the lower frame (13). The same side of the two wing plates of the reinforcing rod (15) is fixedly connected to the same side of the two wing plates of the upper frame (12).

9. The flow velocity measuring device for turbine efficiency testing according to claim 7, characterized in that: Both the upper frame (12) and the lower frame (13) are provided with limiting feet (16), and the limiting feet (16) are located on the water-facing side of the fixed frame (1).

10. The flow velocity measuring device for turbine efficiency testing according to claim 7, characterized in that: The upper frame (12) is provided with a lug (17).

Images