Rotary structure fluid-solid coupling experimental device under influence of gap flow

Abstract

The invention relates to a rotary structure fluid-solid coupling experimental device under the influence of gap flow. Comprising a driving motor, a belt, a shaft system, a cavity, a water inlet ring pipe, a water inlet straight pipe, a circulating water pump, a water outlet ring pipe, a water outlet straight pipe, a piezoelectric ceramic piece, a rotating structure and a pressure pulsation sensor. The cavity is filled with water, and the shaft system and the rotating structure are driven by the driving motor to rotate. By analyzing signals of the pressure pulsation sensor and the acceleration sensor, parameters such as inherent frequency when a vibration signal of the rotating structure is transmitted to a static coordinate system can be obtained. A gap between the rotating structure and the bottom of the cavity can be adjusted through a shaft system, and the size of the gap is measured through a laser range finder. The invention is used for solving the problem that the transmission rule of the vibration signal in a static coordinate system and a rotating coordinate system is not clear when the existing underwater rotating mechanical structure flows in different gaps.

Description

Technical Field

[0001] The invention belongs to the technical field of fluid mechanics and solid mechanics experiments, and in particular relates to a fluid-solid coupling experimental device under the influence of gap flow. Background Art

[0002] As the number of pumped storage power stations further increases, the smooth operation of pumped storage units becomes crucial. The gap flow between the upper crown, lower ring and stationary parts of the runner of hydraulic machinery such as pump turbines will affect the resonance level of the unit.

[0003] At present, there is no experimental research on the effect of gap fluid on the modal parameters of the runner in China. Foreign researchers have found that the natural frequency of the disk increases with the increase of the gap, and the damping decreases with the increase of the gap. In addition, the transmission law of vibration signals between rotating parts and stationary parts still needs to be studied. Summary of the invention

[0004] In view of this, a fluid-solid coupling experimental device under the influence of gap flow is urgently needed to solve the above problems.

[0005] A fluid-solid coupling experimental device for a rotating structure under the influence of gap flow, comprising a driving device, a shaft system, a rotating structure, a cavity, a circulating water pipeline, an excitation device, and a data acquisition device; The cavity is used to hold circulating water; The circulating water circulates in the cavity and the circulating water pipeline; The excitation device is used to apply vibration excitation to the rotating structure; The data acquisition device is used to collect vibration signals of the experimental device; The rotating structure forms a gap with the bottom of the cavity; The shaft system penetrates through and is coupled to the rotating structure and the cavity, and is used to adjust the gap between the rotating structure and the bottom of the cavity; The rotating structure rotates around the axis system; The driving device is used to drive the shaft system and the rotating structure to rotate; The experimental device is used to collect vibration signals in a stationary coordinate system and a rotating coordinate system under different gaps.

[0006] Specifically, the circulating water pipeline includes a water inlet ring pipe, a water inlet straight pipe, a circulating water pump, a water outlet ring pipe and a water outlet straight pipe.

[0007] Based on the above scheme, the water inlet holes on the cavity wall are evenly distributed in the circumferential direction at certain intervals and connected to the water inlet ring pipe; the water outlet holes on the cavity bottom are evenly distributed in the circumferential direction at certain intervals and connected to the water outlet ring pipe.

[0008] On the basis of the above scheme, the excitation device is specifically one or more piezoelectric ceramic sheets, the piezoelectric ceramic sheets are fixedly connected to the rotating structure, one or more of the piezoelectric ceramic sheets are connected to an external signal source, and excitation is applied to the rotating structure, so that it vibrates. At the same time, the piezoelectric ceramic sheets serve as data acquisition devices to collect vibration signals generated by the rotating structure.

[0009] On the basis of the above scheme, the data acquisition device includes a pressure pulsation sensor installed on the top of the cavity, and the pressure pulsation sensor is used to collect the signal when the vibration signal of the rotating structure is transmitted to the stationary coordinate system.

[0010] Specifically, the shaft system is composed of a threaded sleeve, a bearing, an outer shaft, a locking piece, and an inner shaft; The bearing is connected to the cavity by screws and to the outer shaft by interference fit; The locking member connects the outer shaft and the inner shaft via screws; The locking member can slide along the axial direction; The threaded sleeve can control the relative position of the outer shaft and the inner shaft.

[0011] On the basis of the above solution, the outer shaft is a hollow shaft, the upper end of the inner shaft has a hole, and the signal line of the piezoelectric ceramic sheet enters the inner part of the outer shaft through the hole; A threaded ring and a hole are provided on the middle portion of the outer shaft, the threaded ring is connected to the inner shaft through a screw, and can slide along the axial direction under the constraint of the hole and the screw; The lower end of the outer shaft is provided with a locking piece and a hole, and the locking piece can slide along the axial direction under the constraint of the hole and the screw; The signal line of the piezoelectric ceramic sheet is connected to the outer shaft through the hole.

[0012] Based on the above solution, the locking member has a groove at the bottom, and the signal line of the piezoelectric ceramic piece is connected to the rotating structure along the groove; The locking member is provided with a threaded hole, and the locking member is connected to the rotating structure via the threaded hole.

[0013] On the basis of the above scheme, the device can measure the modal vibration shape of the rotating structure containing n node diameters in the rotating coordinate system and the stationary coordinate system; In the same coordinate system, if the circumferential angle between the two data acquisition devices on the rotating structure is , and the phase difference between the signals measured by the two data acquisition devices is ,but Determined by the following relationship: ; The radius of the data acquisition device The radius r setting close to the rotating structure.

[0014] Based on the above solution, the gap is greater than or equal to 2 mm.

[0015] Based on the above solution, the data acquisition device also includes an acceleration sensor for measuring the natural frequency of the rotating structure transferred to the stationary coordinate system.

[0016] Beneficial effects of the present invention: The present invention provides a fluid-solid coupling experimental device solution under the influence of gap flow, which has a simple structure and low implementation cost, and is used to solve the problem that the transmission law of vibration signals of existing underwater rotating mechanical structures under different gap flows in a stationary coordinate system and a rotating coordinate system is unclear. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention has the following accompanying drawings: Figure 1 It is a schematic diagram of the overall structure of a fluid-solid coupling experimental device under the influence of gap flow provided by an embodiment of the present invention; Figure 2 is a schematic diagram of an axis system in a fluid-solid coupling experimental device under the influence of gap flow provided by an embodiment of the present invention; Figure 3 is a schematic diagram of an outer shaft in a fluid-solid coupling experimental device under the influence of gap flow provided by an embodiment of the present invention; Figure 4 is a schematic diagram of an inner shaft in a fluid-solid coupling experimental device under the influence of gap flow provided by an embodiment of the present invention; Figure 5 is a schematic diagram of a locking member in a fluid-solid coupling experimental device under the influence of gap flow provided by an embodiment of the present invention; Figure 6 It is a schematic diagram of a rotating structure and an arrangement of piezoelectric ceramic sheets in a fluid-solid coupling experimental device under the influence of gap flow provided by an embodiment of the present invention; Figure 7 is a schematic diagram of a cavity in a fluid-solid coupling experimental device under the influence of gap flow provided by an embodiment of the present invention; Reference numerals: 1: motor, 2: belt, 3: shaft system, 4: cavity, 5: water inlet ring pipe, 6 water inlet straight pipe, 7 circulating water pump, 8 water outlet ring pipe, 9 piezoelectric ceramic piece, 10 rotating structure, 11 water outlet straight pipe, 12 pressure pulsation sensor, 13 transparent ranging window, 14 laser rangefinder, 301 threaded ring pipe, 302 bearing, 303 outer shaft, 304 locking piece, 305 inner shaft, 306 locking piece screw, 3031 outer shaft upper end hole, 3032 outer shaft middle end hole, 3033 threaded ring, 3034 outer shaft lower end hole, 3035 threaded ring screw, 3051 inner shaft upper end hole, 3052 inner shaft middle end hole, 3053 inner shaft lower end hole, 3041 locking piece slot, 3042 locking piece threaded hole, 101 rotating structure slot, 102 rotating structure threaded hole, 401 water inlet hole, 402 water outlet hole. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0020] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0021] like Figures 1 to 7The present invention provides a fluid-solid coupling experimental device under the influence of gap flow, which specifically includes: components for driving solid rotation such as a driving motor, a belt, a shaft system and a rotating structure, components for driving fluid flow such as a cavity, a water inlet ring pipe, a water inlet straight pipe, a circulating water pump, a water outlet ring pipe and a water outlet straight pipe, and components for data collection such as a piezoelectric ceramic piece and a pressure pulsation sensor.

[0022] like Figure 1 As shown, in a specific implementation, one or more of the piezoelectric ceramic sheets 9 are connected to an external signal source to excite the rotating structure 10 to generate vibration. The pressure pulsation sensor 12 is installed on the top of the cavity, and the pressure pulsation sensor can collect the signal when the vibration signal of the rotating structure 10 is transmitted to the stationary coordinate system. One or more of the piezoelectric ceramic sheets 9 can measure the vibration response of the rotating structure 10 under the coupling of the water pressure pulsation in the rotating coordinate system, and transmit it to the outside world.

[0023] The fluid-solid coupling experimental device under the influence of gap flow can change the gap between the rotating structure 10 and the bottom surface of the cavity 4 through the shaft system 3, realize the collection of signals in the stationary coordinate system and the rotating coordinate system under different gaps, and calibrate the relationship between the three.

[0024] It should be pointed out that the gap λ between the rotating structure and the bottom of the cavity can be measured by a laser rangefinder. It should be noted that in order to deeply study the law between parameters such as the gap and the natural frequency, the minimum value of λ should reach 2 mm.

[0025] like Figure 2 As shown, in a specific embodiment, the shaft system 3 is composed of a threaded sleeve 301 , a bearing 302 , an outer shaft 303 , a locking member 304 , and an inner shaft 305 .

[0026] The bearing 302 is connected to the cavity 4 by screws and connected to the outer shaft 303 by interference fit. The locking member 304 is connected to the outer shaft 303 and the inner shaft 305 by screws 306. The locking member 304 can slide along the axial direction. The threaded sleeve 301 can control the relative position of the outer shaft 303 and the inner shaft 305.

[0027] like Figure 3 As shown, in a specific embodiment, the outer shaft is a hollow shaft, and the signal line of the piezoelectric ceramic piece 9 is connected to the inner part of the outer shaft 303 through the hole 3031. The threaded ring 3033 is connected to the inner shaft 305 through the screw 3035, and can slide along the axial direction under the constraint of the hole 3032 and the screw 3035. The locking member 304 can slide along the axial direction under the constraint of the hole 3034 and the screw 306. The signal line of the piezoelectric ceramic piece 9 is connected to the outer shaft 305 through the hole 3034.

[0028] like Figure 4 As shown, in a specific embodiment, the inner shaft is a hollow shaft, and the inner shaft is connected to the screw 3035 on the threaded ring 3033 through the threaded hole 3051. Under this constraint, the inner shaft 305 can slide along the axial direction. The locking member 304 is connected to the threaded hole 3052 through the screw 306. The signal line of the piezoelectric ceramic plate 9 is connected to the inner shaft 305 through the hole 3053.

[0029] like Figure 5 As shown, in a specific embodiment, the signal line of the piezoelectric ceramic sheet 9 is connected to the piezoelectric ceramic sheet 9 along the groove 3041 on the locking member 304. The screw 306 is connected to the hole 3052 on the inner shaft 305. The locking member 304 is connected to the rotating structure 10 through the threaded hole 3042.

[0030] like Figure 6 As shown, in a specific embodiment, the rotating structure 10 is connected to the piezoelectric ceramic sheet 9 by glue or the like. The signal line of the piezoelectric ceramic sheet 9 is connected to the piezoelectric ceramic sheet 9 through the groove 101. The hole 102 is screwed to the threaded hole 3043 to realize the connection between the rotating structure 10 and the locking member 304.

[0031] like Figure 7 As shown, in a specific embodiment, the water inlet holes 401 on the cavity 4 are evenly distributed in the circumferential direction at intervals of 90 degrees, and are connected to the water inlet ring pipe 6, ensuring the uniformity of the flow. The water outlet holes 402 on the cavity 4 are evenly distributed in the circumferential direction at intervals of 90 degrees, and are connected to the water outlet ring pipe 8, ensuring the uniformity of the flow.

[0032] It should be pointed out that the modal vibration shape of the rotating structure containing n nodal diameters (the diameter where the vibration amplitude is 0) can be measured in both the rotating coordinate system and the stationary coordinate system. In the same coordinate system, if the circumferential angle between the two measuring sensors is , and the phase difference between the signals measured by the two sensors is ,but Determined by the following relationship: ; It should be noted that this method can only determine the number of node diameters of the modal vibration shape at the corresponding frequency, and cannot visualize the modal vibration shape. In addition, in order to make the measured signal-to-noise ratio higher, the radius where all sensor centers are located It should be as close as possible to the radius r of the rotating structure.

[0033] The above embodiments describe the technical solutions of the present invention in detail. Obviously, the present invention is not limited to the described embodiments. Based on the embodiments of the present invention, people familiar with the technical field can also make various changes accordingly, but any changes that are equivalent or similar to the present invention belong to the scope of protection of the present invention.

[0034] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

Claims

1. A rotating structure fluid-solid coupling experimental device under the influence of gap flow, characterized in that: It includes a driving device, a shaft system, a rotating structure, a cavity, a circulating water pipeline, an excitation device, and multiple data acquisition devices; The cavity is used to hold circulating water; The circulating water circulates in the cavity and the circulating water pipeline; The excitation device is used to apply vibration excitation to the rotating structure; The data acquisition device is used to collect vibration signals of the experimental device; The rotating structure forms a gap with the bottom of the cavity; The shaft system penetrates through and is coupled to the rotating structure and the cavity, and is used to adjust the gap between the rotating structure and the bottom of the cavity; The rotating structure rotates around the axis system; The driving device is used to drive the shaft system and the rotating structure to rotate; The experimental device is used to collect vibration signals in a stationary coordinate system and a rotating coordinate system under different gaps.

2. The experimental device according to claim 1, characterized in that: The circulating water pipeline comprises a water inlet ring pipe, a water inlet straight pipe, a circulating water pump, a water outlet ring pipe and a water outlet straight pipe.

3. The experimental device according to claim 2, characterized in that: The water inlet holes on the cavity wall are evenly distributed in the circumferential direction and connected to the water inlet ring pipe; the water outlet holes on the cavity bottom are evenly distributed in the circumferential direction and connected to the water outlet ring pipe.

4. The experimental device according to claim 1, characterized in that: The excitation device is specifically one or more piezoelectric ceramic sheets, the piezoelectric ceramic sheets are fixedly connected to the rotating structure, one or more of the piezoelectric ceramic sheets are connected to an external signal source, and apply excitation to the rotating structure, so that it generates vibration; At the same time, the piezoelectric ceramic piece also serves as a data acquisition device to collect vibration signals generated by the rotating structure.

5. The experimental device according to claim 1, characterized in that: The data acquisition device comprises a pressure pulsation sensor installed on the top of the cavity, and the pressure pulsation sensor is used to collect signals when the vibration signal of the rotating structure is transmitted to the stationary coordinate system.

6. The experimental device according to claim 4, characterized in that: The shaft system is composed of a threaded sleeve, a bearing, an outer shaft, a locking piece, and an inner shaft; The bearing is connected to the cavity by screws and to the outer shaft by interference fit; The locking member connects the outer shaft and the inner shaft via screws; The locking member slides along the axial direction; The threaded sleeve controls the relative position of the outer shaft and the inner shaft.

7. The experimental device according to claim 6, characterized in that: The outer shaft is a hollow shaft, and a hole is formed at the upper end of the inner shaft, and the signal line of the piezoelectric ceramic sheet enters the inner part of the outer shaft through the hole; A threaded ring and a hole are provided on the middle portion of the outer shaft, the threaded ring is connected to the inner shaft through a screw and slides along the axial direction under the constraint of the hole and the screw; The lower end of the outer shaft is provided with a locking piece and a hole, and the locking piece slides along the axial direction under the constraint of the hole and the screw; The signal line of the piezoelectric ceramic sheet is connected to the outer shaft through the hole; The bottom of the locking member is provided with a groove, and the signal line of the piezoelectric ceramic sheet is connected to the rotating structure along the groove; The locking member is provided with a threaded hole, and the locking member is connected to the rotating structure via the threaded hole.

8. The experimental device according to any one of claims 1 to 7, characterized in that: The device measures and obtains the modal vibration shape of the rotating structure containing n node diameters in a rotating coordinate system and a stationary coordinate system; In the same coordinate system, if the circumferential angle between the two data acquisition devices on the rotating structure is , and the phase difference between the signals measured by the two data acquisition devices is ,but Determined by the following relationship: ； The radius r where the data acquisition device is located The radius r setting close to the rotating structure.

9. The experimental device according to any one of claims 1 to 7, characterized in that: The gap is greater than or equal to 2 mm.

10. The experimental device according to any one of claims 1 to 7, characterized in that: The data acquisition device also includes an acceleration sensor for measuring the natural frequency of the rotating structure transferred to the stationary coordinate system.

Images