Impact type runner dynamic stress testing device and method

Abstract

The invention belongs to the technical field of runner dynamic stress testing, and particularly relates to an impact type runner dynamic stress testing device and method. According to the technical scheme, the impact type rotating wheel dynamic stress testing device comprises a main shaft, a rotating wheel body is installed at the lower end of the main shaft, a plurality of water buckets are arranged on the rotating wheel body, fixing tools are fixed to the upper end and the lower end of the main shaft, a steel wire rope is connected between the fixing tools, and a wireless module tool is installed at the top of the main shaft; a strain gauge is adhered to the water bucket, the strain gauge is connected with a signal cable, the signal cable is adhered to the surfaces of the water bucket and the rotating wheel main body, and the signal cable penetrates into the main shaft from the lower end surface of the rotating wheel main body, is wound on the steel wire cable and then is connected with the wireless module tool. According to the impact type rotating wheel dynamic stress testing device and method, the performance of the rotating wheel and the main shaft is not affected, the signal cable is protected to the maximum extent, and the signal transmission mode is stable and reliable.

Description

Technical Field

[0001] This invention belongs to the field of dynamic stress testing technology for wheel sprockets, and specifically relates to an impact-type dynamic stress testing device and method for wheel sprockets. Background Technology

[0002] The impulse runner is a crucial component of an impulse turbine. The dynamic stress level of the impulse runner under actual machine operation is one of the main factors affecting the performance and stability of the impulse turbine. During operation, the impulse runner is frequently impacted by high-speed water flow from the nozzles. The impact pressure on the buckets of the impulse runner is high and unsustainable, making the bucket roots prone to fatigue, which can lead to cracks or bucket breakage in severe cases. Understanding the dynamic stress condition of the impulse runner is fundamental to studying fatigue cracks in the impulse turbine runner and estimating its lifespan.

[0003] The existing method for testing the dynamic stress of impact-type impellers involves setting cable holes on the impeller for cable threading. The cable holes extend directly to the center of the impeller body or the flange surface. The signal cable from the test device is first passed through the cable holes into the spindle, then out from the generator end of the spindle, and finally introduced into the central control room for dynamic stress detection.

[0004] The prior art differs from the proposal of this application in the following ways: 1) Existing wiring methods require machining cable holes or welding cable protection tubes on the wheel and spindle. Signal cables need to pass through the cable holes or cable protection tubes to enter the center of the spindle. The size of the hole depends on the number of measuring points, and the number of measuring points is limited. Opening holes will cause stress concentration problems in the wheel body, and welding will cause residual stress on the surface of the wheel body. If the above problems cannot be solved well, cracks or even bucket breakage will occur, resulting in major safety accidents.

[0005] 2) In the existing technology, the signal cable is inserted into the center of the runner body and then manually straightened and passed through the center hole of the turbine and the center hole of the generator before finally being led out of the main shaft. The signal cable is directly subjected to the high-speed centrifugal force, which can lead to the signal cable breaking or tangling.

[0006] 3) Existing signal transmission technologies employ contact transmission or memory card storage. Contact transmission often uses contact brush rings or pull-wire current collectors; memory card storage stores data in the strain gauge, but it cannot detect signals in real time and can only perform post-processing. Contact transmission causes mechanical wear, requiring frequent replacement. Signal transmission efficiency is limited by rotational speed, and frequent cleaning and component replacement result in significant downtime losses and high maintenance costs. Summary of the Invention

[0007] In order to solve the above-mentioned problems in the existing technology, the purpose of this invention is to provide an impact-type rotary wheel dynamic stress testing device and method, which does not affect the performance of the rotary wheel and spindle, protects the signal cable to the greatest extent, and ensures stable and reliable signal transmission.

[0008] The technical solution adopted in this invention is as follows: An impact-type rotary dynamic stress testing device includes a main shaft, a rotary body mounted on the lower end of the main shaft, several water buckets mounted on the rotary body, and fixed fixtures fixed at both the upper and lower ends of the main shaft. Steel wire cables are connected between the fixed fixtures, and a wireless module fixture is mounted on the top of the main shaft. Strain gauges are attached to the water buckets, and signal cables are connected to the strain gauges. The signal cables are attached to the surfaces of the water buckets and the rotary body, and pass through the main shaft from the lower end face of the rotary body, then wrap around the steel wire cable and connect to the wireless module fixture.

[0009] In this invention, the strain gauge and signal cable are both attached to the surface of the water tank or the main body of the impeller. The signal cable passes through the main shaft from the lower end face of the impeller body and is then wound around the steel wire rope before being connected to the wireless module tooling. This eliminates the need for processing and welding on the surfaces of the water tank, the impeller body, and the main shaft, without affecting the performance of the impeller and the main shaft, and without affecting the safe operation of the unit.

[0010] In this invention, the signal cable is wound around a steel wire rope, which completely restrains the signal cable. The steel wire rope is tightened and fixed to the center of the main shaft by a tensioner, and the steel wire rope bears the centrifugal force, thus protecting the signal cable to the greatest extent.

[0011] This invention transmits signals via a wireless module fixture, enabling real-time monitoring of dynamic stress changes in the water bucket. It obtains real-time dynamic stress data of the water bucket during normal unit operation and assesses the water bucket's safety performance based on this data. The signal transmission method employed in this invention is wireless, ensuring stable and reliable signal transmission.

[0012] As a preferred embodiment of the present invention, the strain gauges and signal cables are covered with metal repair agent at the points along their paths through the water tank and the main body of the impeller.

[0013] In a preferred embodiment of the present invention, the metal repair agent is applied to the surface of the water tank and the impeller body in a streamlined shape. The signal cable is fixed to the surface of the water tank in a streamlined shape using the metal repair agent, without changing the flow pattern on the surface of the water tank, while reducing flow resistance and improving impact resistance.

[0014] In a preferred embodiment of the present invention, a lower end cover is connected to the bottom of the rotor body. Both the upper end of the lower end cover and the lower end of the rotor body are provided with several semi-circular holes. The lower end cover, the semi-circular holes, and the semi-circular holes of the rotor body are combined to form a circular hole, through which the signal cable passes. A circular hole is opened at the contact point between the lower end cover and the rotor body. The lower end cover is a non-critical component, and the circular hole needs to be sealed with sealant during testing, thus having no impact on the operation of the unit.

[0015] As a preferred embodiment of the present invention, the fixing fixture is a cross structure, which is welded inside the main shaft. The welding position is in a non-working area, so as not to affect the performance of the wheel and the main shaft and the normal operation of the unit. The steel wire cable is fixed between the two cross structures.

[0016] In a preferred embodiment of the present invention, after the end of the steel wire rope is wound around the cross structure, it is locked onto the cross structure by a lock. When connecting the steel wire rope, the steel wire rope is first wound around the upper fixing fixture, locked by the lock, and then the steel wire rope is tightened at the lower end by a tensioner, and then the locking fixture at the lower end is fixed.

[0017] In a preferred embodiment of the present invention, the wireless module fixture includes a transition flange cover plate fixed to the top of the spindle, a support block mounted on the transition flange cover plate, and a wireless dynamic strain gauge mounted on the support block. The upper end of the signal cable is connected to the wireless dynamic strain gauge. The wireless module fixture is fixed to the top of the spindle by bolts, and can be replaced and charged at any time when the machine is stopped. The wireless dynamic strain gauge of the present invention realizes real-time signal acquisition and analysis through WIFI technology.

[0018] As a preferred embodiment of the present invention, a protective cover is also connected to the transition flange cover plate, and the protective cover shields the wireless dynamic strain gauge.

[0019] As a preferred embodiment of the present invention, the signal cable is wrapped around a steel wire rope and then fixed by insulating tape and binding tape.

[0020] A method for testing the dynamic stress of an impact-type turbine runner includes the following steps: S1: After selecting the measuring point position on the water bucket and smoothing it, attach the strain gauge; S2: Wrap the signal cables around the steel wire rope in the same direction in sequence; S3: Weld the fixture to the upper and lower end faces of the spindle; S4: First, wrap the steel wire rope around the upper fixing fixture and lock it with the buckle. Then, tighten the steel wire rope at the lower end with the tensioner and lock it with the buckle to fix the fixing fixture at the lower end. S5: Secure the wireless dynamic strain gauge to the transition flange cover plate with bolts; S6: Lead the signal cable along the bottom of the rotor body to the water bucket measuring point and connect the strain gauge; S7: Cover all strain gauges and signal cables at all measuring points with metal repair agent along their paths on the water tank and impeller body; S8: Install the lower end cover. During installation, align the round hole with the signal cable. After installation, fill any remaining gaps with sealant. S9: Connect the signal cable to the wireless dynamic strain gauge; S10: Collect dynamic water bucket stress data.

[0021] The beneficial effects of this invention are as follows: 1. In this invention, the strain gauge and signal cable are both attached to the surface of the water tank or the main body of the impeller. The signal cable passes through the main shaft from the lower end face of the impeller body and is then wound around the steel wire cable and connected to the wireless module tooling. Therefore, it is not necessary to process and weld the surface of the water tank, the impeller body and the main shaft, and it does not affect the performance of the impeller and the main shaft, nor does it affect the safe operation of the unit.

[0022] 2. In this invention, the signal cable is wound around a steel wire rope, which completely restrains the signal cable. The steel wire rope is tightened and fixed to the center of the main shaft by a tensioner, and the steel wire rope bears the centrifugal force, thus protecting the signal cable to the greatest extent.

[0023] 3. This invention transmits signals via a wireless module fixture, enabling real-time monitoring of dynamic stress changes in the water bucket and obtaining real-time dynamic stress data of the water bucket during normal unit operation. The safety performance of the water bucket can then be assessed based on this real-time dynamic stress data. The signal transmission method employed in this invention is wireless, ensuring stable and reliable signal transmission. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 It is an assembly diagram of the signal cable and the water tank; Figure 3 This is a schematic diagram of the lower end cover. Figure 4 This is a structural diagram of a fixed tooling; Figure 5 This is a structural schematic diagram of a wireless module fixture.

[0025] In the diagram: 1-Main shaft; 2-Rotating wheel body; 3-Water bucket; 4-Fixed fixture; 5-Steel wire rope; 6-Wireless module fixture; 7-Signal cable; 8-Metal repair agent; 9-Lower end cover; 61-Transition flange cover; 62-Support block; 63-Wireless dynamic strain gauge; 64-Protective cover; 65-Lead wire bracket; 91-Semi-circular hole. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the invention can be combined with each other.

[0028] like Figures 1-4 As shown, the impact-type rotary dynamic stress testing device of this embodiment includes a main shaft 1, a rotary body 2 mounted on the lower end of the main shaft 1, several water tanks 3 arranged on the rotary body 2, and fixing fixtures 4 fixed at both the upper and lower ends of the main shaft 1. Steel wire cables 5 are connected between the fixing fixtures 4, and a wireless module fixture 6 is mounted on the top of the main shaft 1. Strain gauges are attached to the water tanks 3, and signal cables 7 are connected to the strain gauges. The signal cables 7 are attached to the surfaces of the water tanks 3 and the rotary body 2. The signal cables 7 pass through the lower end face of the rotary body 2 into the main shaft 1, are then wound around the steel wire cable 5, and are connected to the wireless module fixture 6. The signal cables 7 are fixed by insulating tape and binding tape after being wound around the steel wire cable 5.

[0029] In this invention, the strain gauge and signal cable 7 are both attached to the surface of the water tank 3 or the main body 2 of the impeller. The signal cable 7 passes through the lower end face of the impeller body 2 into the main shaft 1 and is then wound around the steel wire rope 5 before being connected to the wireless module fixture 6. Therefore, it is not necessary to process and weld the surfaces of the water tank 3, the impeller body 2 and the main shaft 1, and it does not affect the performance of the impeller and the main shaft 1, nor does it affect the safe operation of the unit.

[0030] In this invention, the signal cable 7 is wound around the steel wire rope 5, so that the signal cable 7 is completely constrained by the steel wire rope 5. The steel wire rope 5 is tightened and fixed to the center of the main shaft 1 by the tensioner. The steel wire rope 5 bears the centrifugal force, which greatly protects the signal cable 7.

[0031] This invention transmits signals via a wireless module fixture 6, enabling real-time monitoring of the dynamic stress changes in the water tank 3. It obtains real-time dynamic stress data of the water tank 3 during normal unit operation and assesses the safety performance of the water tank 3 based on this data. The signal transmission in this invention is wireless, ensuring stable and reliable signal transmission.

[0032] Furthermore, the strain gauge and signal cable 7 are covered with a metal repair agent 8 at their respective paths through the water tank 3 and the impeller body 2. The metal repair agent 8 is applied in a streamlined shape on the surfaces of the water tank 3 and the impeller body 2. The signal cable 7 is fixed to the surface of the water tank 3 with a streamlined shape using the metal repair agent 8, without changing the flow pattern on the surface of the water tank 3, while reducing flow resistance and improving impact resistance.

[0033] Furthermore, a lower end cover 9 is connected to the bottom of the rotor body 2. Both the upper end of the lower end cover 9 and the lower end of the rotor body 2 are provided with several semi-circular holes 91. The lower end cover 9, the semi-circular holes 91, and the semi-circular holes 91 of the rotor body 2 are combined to form a circular hole, through which the signal cable 7 passes. A circular hole is opened at the contact point between the lower end cover 9 and the rotor body 2. The lower end cover 9 is a non-critical component, and the circular hole needs to be sealed with sealant during testing, having no impact on the unit's operation.

[0034] Among them, such as Figure 4 As shown, the fixed fixture 4 is a cross structure, which is welded inside the main shaft 1. The welding position is in a non-working area and does not affect the performance of the wheel and the main shaft or the normal operation of the unit. The steel wire cable 5 is fixed between the two cross structures.

[0035] After the end of the steel wire cable 5 is wrapped around the cross structure, it is locked onto the cross structure by a lock. When connecting the steel wire cable 5, the steel wire cable 5 is first wrapped around the upper fixing fixture 4 and locked by the lock. Then, the steel wire cable 5 is tightened at the lower end by a tensioner and then fixed to the lower fixing fixture 4 by the lock.

[0036] Specifically, such as Figure 5 As shown, the wireless module fixture 6 includes a transition flange cover plate 61 fixed to the top of the spindle 1. A support block 62 is mounted on the transition flange cover plate 61, and a wireless dynamic strain gauge 63 is mounted on the support block 62. The upper end of the signal cable 7 is connected to the wireless dynamic strain gauge 63. The wireless module fixture 6 is fixed to the top of the spindle 1 by bolts, and can be replaced and charged at any time when the machine is stopped. The wireless dynamic strain gauge 63 of this invention realizes real-time signal acquisition and analysis through WIFI technology.

[0037] A protective cover 64 is also connected to the transition flange cover 61, which shields the wireless dynamic strain gauge 63. A lead wire bracket 65 is also connected to the transition flange cover 61.

[0038] It should be noted that the length of the signal cable 7 must meet the requirements of the shaft length plus the length required for connecting the wireless module fixture 6 at the upper end and the strain gauge at the lower end. The length of the steel wire rope 5 must meet the requirements of the shaft length plus the length required for additional fixing at the fixture 4. When there are many signal cables 7, the number or diameter of the steel wire rope 5 can be appropriately increased.

[0039] The impact-type impeller dynamic stress testing method of this embodiment includes the following steps: S1: After selecting the measuring point position on water tank 3 and smoothing it, attach the strain gauge; S2: Wrap the signal cable 7 around the steel wire rope 5 in the same direction; be sure to allow sufficient length for both the steel wire rope 5 and the signal cable 7. S3: Weld the fixture 4 to the upper and lower end faces of the spindle 1; S4: First, wrap the steel wire rope 5 around the upper fixing fixture 4 and lock it with the buckle. Then, tighten the steel wire rope 5 at the lower end with the tensioner and then fix the fixing fixture 4 at the lower end with the buckle. S5: Secure the wireless dynamic strain gauge 63 to the transition flange cover plate 61 with bolts; S6: Lead the signal cable 7 along the bottom of the rotor body 2 to the measuring point position of the water tank 3, and connect the strain gauge; S7: Cover all strain gauges and signal cables 7 at all measuring points along their paths on the water tank 3 and the main body of the impeller 2 with metal repair agent 8; S8: Install the lower end cover. During installation, align the round hole with signal cable 7. After installation, fill any remaining gaps with sealant. S9: Connect the signal cable 7 to the wireless dynamic strain gauge 63; S10: Collect stress data for dynamic water bucket 3.

[0040] In summary, the strain gauge signal cable 7 of the present invention is routed along the water tank 3 and finally converges at the lower part of the center of the impeller. Only the lower end cover 9 is machined with a round hole. The key parts of the impeller and the main shaft 1 are not machined or welded. Therefore, the performance of the impeller and the main shaft 1 is not affected, and the safe operation of the unit is not affected.

[0041] The signal cable 7 of the present invention is coated with metal repair agent 8 and fixed to the surface of water tank 3 in a streamlined shape without changing the flow state of the surface of water tank 3, while reducing flow resistance and improving impact resistance.

[0042] This invention eliminates the need for welding, grinding, or other repair work on the rotor body after the test. The metal repair agent 8 on the rotor will automatically fall off under the impact of water flow for a long time, thus avoiding secondary damage to the rotor body.

[0043] This invention can monitor the dynamic stress changes of the water bucket 3 in real time, obtain real-time dynamic stress data of the water bucket 3 during normal operation of the unit, and evaluate the safety performance of the water bucket 3 based on the real-time dynamic stress data.

[0044] The signal transmission of this invention adopts a wireless transmission method, which ensures stable and reliable signal transmission. In this invention, the signal cable 7 is wound around the steel wire rope 5, and is fixed with insulating tape and binding tape, so that the signal cable 7 is completely constrained by the steel wire rope 5. The steel wire rope 5 is tightened and fixed to the center of the main shaft 1 by a tensioner, and the steel wire rope 5 bears the centrifugal force, which greatly protects the signal cable 7.

[0045] The signal acquisition of this invention adopts a modular design. The number of modules can be increased or decreased according to the number of measurement points. Multiple protective covers 64 of different sizes can be designed in advance, and different modules do not interfere with each other.

[0046] The wireless dynamic strain gauge 63 of the present invention is fixed with bolts, which facilitates installation and charging.

[0047] This invention is not limited to the above-described optional embodiments. Anyone can derive other various forms of products under the guidance of this invention. However, regardless of any changes made in their shape or structure, any technical solution that falls within the scope of the claims of this invention shall be protected by this invention.

Claims

1. An impact-type rotary dynamic stress testing device, characterized in that: The device includes a main shaft (1), a rotating body (2) installed at the lower end of the main shaft (1), a number of water buckets (3) on the rotating body (2), a fixing fixture (4) fixed at the upper and lower ends of the main shaft (1), a steel wire cable (5) connected between the fixing fixtures (4), and a wireless module fixture (6) installed on the top of the main shaft (1). Strain gauges are attached to the water buckets (3), and the strain gauges are connected to signal cables (7). The signal cables (7) are attached to the surfaces of the water buckets (3) and the rotating body (2). The signal cables (7) pass through the main shaft (1) from the lower end face of the rotating body (2), and are then wound around the steel wire cable (5) and connected to the wireless module fixture (6).

2. The impact-type rotary dynamic stress testing device according to claim 1, characterized in that: The strain gauges and signal cables (7) are covered with metal repair agent (8) at the locations along the paths of the water tank (3) and the main body of the impeller (2).

3. The impact-type rotary dynamic stress testing device according to claim 2, characterized in that: The metal repair agent (8) is applied in a streamlined shape on the surface of the water tank (3) and the main body of the impeller (2).

4. The impact-type rotary dynamic stress testing device according to claim 1, characterized in that: The bottom of the rotating body (2) is connected to a lower end cover (9). The upper end of the lower end cover (9) and the lower end of the rotating body (2) are provided with several semi-circular holes (91). The lower end cover (9) and the semi-circular holes (91) and the semi-circular holes (91) of the rotating body (2) are combined to form a circular hole, through which the signal cable (7) passes.

5. The impact-type rotary dynamic stress testing device according to claim 1, characterized in that: The fixed fixture (4) is a cross structure, which is welded inside the main shaft (1). The welding position is in the non-working area and does not affect the performance of the wheel and the main shaft or the normal operation of the unit. The steel wire rope (5) is fixed between the two cross structures.

6. The impact-type rotary dynamic stress testing device according to claim 5, characterized in that: After the end of the steel wire rope (5) is wrapped around the cross structure, it is locked onto the cross structure by a buckle.

7. The impact-type rotary dynamic stress testing device according to claim 1, characterized in that: The wireless module fixture (6) includes a transition flange cover plate (61) fixed to the top of the spindle (1), a support block (62) is installed on the transition flange cover plate (61), a wireless dynamic strain gauge (63) is installed on the support block (62), and the upper end of the signal cable (7) is connected to the wireless dynamic strain gauge (63).

8. The impact-type rotary dynamic stress testing device according to claim 7, characterized in that: The transition flange cover (61) is also connected to a protective cover (64), which shields the wireless dynamic strain gauge (63).

9. The impact-type rotary dynamic stress testing device according to claim 7, characterized in that: The signal cable (7) is wrapped around the steel wire rope (5) and then secured with insulating tape and binding tape.

10. A method for testing the dynamic stress of an impact-type impeller, using the dynamic stress testing device for an impact-type impeller as described in any one of claims 1 to 9, characterized in that: Includes the following steps: S1: After selecting the measuring point position on the water tank (3), grind it smooth and then attach the strain gauge; S2: Wrap the signal cable (7) around the steel wire rope (5) in the same direction; S3: Weld the fixed fixture (4) to the upper and lower end faces of the spindle (1); S4: First, wrap the steel wire rope (5) around the upper fixing fixture (4), lock it with the buckle, then tighten the steel wire rope (5) at the lower end with the tensioner, and then fix the fixing fixture (4) wrapped around the lower end with the buckle. S5: Secure the wireless dynamic strain gauge (63) to the transition flange cover plate (61) with bolts; S6: Lead the signal cable (7) along the bottom of the main body (2) of the impeller to the measuring point of the water tank (3) and connect the strain gauge; S7: Cover all strain gauges and signal cables (7) at all measuring points with metal repair agent (8) along their paths on the water tank (3) and the main body of the impeller (2). S8: Install the lower end cover. When installing, align the round hole with the signal cable (7). After installation, fill the remaining gap with sealant. S9: Connect the signal cable (7) to the wireless dynamic strain gauge (63); S10: Collect stress data of dynamic water bucket (3).

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