Vibration and noise reduction efficient energy recovery hydraulic turbine device

Abstract

The utility model relates to the technical field of centrifugal pump reverse rotation turbines, and discloses a vibration and noise reduction efficient energy recovery hydraulic turbine device which comprises a guide vane, an impeller and a main shaft. The number of the first blades is the same as that of the second blades, the first blades and the second blades are distributed at intervals, the impeller is in threaded connection with the main shaft, a cavity is formed in the guide vane, and the main shaft and the impeller are assembled in the cavity. The main shaft, the impeller and the guide vane are assembled and then installed in a straight section type volute. The straight section type volute is adopted, the overflowing performance of fluid can be improved, the impeller is connected to the main shaft in a threaded mode, the main shaft is installed in the guide vane, the guide vane is integrally installed in the straight section type volute, and noise caused by flow in a turbine flow channel and unit vibration caused by the noise can be reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of centrifugal pump counter-rotation turbine operation, and more specifically, to a vibration-reducing, noise-reducing, and high-efficiency energy recovery hydraulic turbine device. Background Art

[0002] In process industries such as petrochemicals, coal chemical industry and seawater desalination, there are large amounts of high-pressure fluids with great pressure energy. At present, my country uses centrifugal pumps to reverse and act as turbines (i.e., liquid energy recovery turbines, referred to as hydraulic turbines) to recover these high-pressure energies. When hydraulic turbines recover the residual pressure energy of high-pressure fluids, they have the disadvantages of low recovery efficiency, high unit noise, and unstable operation. Therefore, in order to improve the energy recovery efficiency of the turbine and improve the operational stability of the turbine unit, it is necessary to optimize the structure of the traditional hydraulic turbine device and transform it into a high-efficiency, low-noise hydraulic turbine unit. Utility Model Content

[0003] The purpose of the utility model is to provide a high-efficiency energy recovery hydraulic turbine device with vibration reduction and noise reduction to solve the problems existing in the prior art. The use of a straight-section volute can improve the flow performance of the fluid, the impeller is threadedly connected to the main shaft, the main shaft is installed in the guide vane, and the guide vane is installed as a whole in the straight-section volute, which can reduce the flow-induced noise in the turbine flow channel and the vibration of the unit caused by it.

[0004] To achieve the above-mentioned objectives, the present invention provides the following solution: The present invention provides a vibration-reducing and noise-reducing high-efficiency energy recovery hydraulic turbine device, comprising: a guide vane, an impeller and a main shaft, wherein a first blade and a second blade are fixedly mounted on the impeller, the first blade and the second blade are the same in number and the first blade and the second blade are spaced apart, the impeller is threadedly connected to the main shaft, a cavity is provided in the guide vane, the main shaft and the impeller are assembled in the cavity, and the main shaft, the impeller and the guide vane are assembled and installed in a straight-section volute.

[0005] According to a vibration-reducing and noise-reducing high-efficiency energy recovery hydraulic turbine device provided by the utility model, the first blade and the second blade are in an arc-shaped structure, and the length of the first blade is greater than the length of the second blade.

[0006] According to the vibration-reducing and noise-reducing high-efficiency energy recovery hydraulic turbine device provided by the utility model, a through hole is opened at the center of the impeller, and an internal thread is provided in the through hole.

[0007] According to a vibration reduction and noise reduction high-efficiency energy recovery hydraulic turbine device provided by the utility model, one end of the main shaft is provided with an external thread, and the end of the main shaft provided with the external thread is threadedly connected to the impeller through the through hole and fixed by a nut.

[0008] According to a vibration-reducing and noise-reducing high-efficiency energy recovery hydraulic turbine device provided by the utility model, the guide vane is sleeved with the main shaft, and the main shaft and the impeller are located in the cavity inside the guide vane.

[0009] According to a vibration-reducing and noise-reducing high-efficiency energy recovery hydraulic turbine device provided by the utility model, the water-passing section of the straight-section volute adopts a circular section, and the straight-section volute is a transparent straight-section volute.

[0010] The utility model discloses the following technical effects:

[0011] This device replaces the traditional tapered volute with a straight-section volute, improving fluid flow performance. Compared to the original turbine volute, the straight-section volute reduces the sound pressure level at the turbine inlet and outlet, reducing hydrodynamic noise generated within the turbine and improving the acoustic and flow field performance at the turbine inlet and outlet. Guide vanes are positioned between the straight-section volute and the impeller to increase the circulation at the impeller inlet and guide the fluid. Fluid flows from the guide vane outlet into the impeller inlet, flattening the load curves for the first and second blades from the impeller inlet to the outlet, thereby increasing energy conversion. The dynamic-static interference between the impeller and the volute is a major factor in flow-induced noise in hydraulic turbines. By shifting the interference between the dynamic and static rotors from the original volute and impeller to the impeller and guide vanes, this reduced dynamic-static interference reduces the radial force acting on the turbine impeller, further reducing flow-induced noise within the turbine flow path and the resulting unit vibration. Adding a second blade with the same number as the first blade to the impeller can weaken the dynamic and static interference at the baffle and between the impeller and the volute, thereby weakening the dipole sound source caused by it, improving the sound pressure level of the flow-through components of the hydraulic turbine, and thus having the effect of reducing the noise of the hydraulic turbine. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0013] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0014] Figure 2 This is a schematic structural diagram of the guide vanes and impeller in the utility model;

[0015] Figure 3 This is a schematic diagram of the structure of the guide vane and the other side of the impeller in the present invention;

[0016] Figure 4This is the assembly diagram of the main shaft and guide vanes in the utility model;

[0017] Figure 5 The water body diagram of the impeller with different first blade and second blade numbers;

[0018] Figure 6 The external characteristic curves of the turbine with different numbers of first blades and second blades;

[0019] Figure 7 is the inlet and outlet sound pressure level at the frequency characteristic;

[0020] Figure 8 The external field noise radiation distribution diagram of the shell dipole at the blade frequency;

[0021] Figure 9 This is the sound pressure contour of the dipole sound source of the straight-section volute casing;

[0022] Figure 10 This is the sound pressure contour of the dipole sound source of the contracted volute casing;

[0023] Among them, 1. guide vane; 2. impeller; 201. first blade; 202. second blade; 203. perforation; 3. main shaft; 4. volute. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only 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 making creative efforts are within the scope of protection of the present invention.

[0025] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0026] like Figures 1-4 As shown, the utility model provides a vibration-reducing and noise-reducing high-efficiency energy recovery hydraulic turbine device including: a guide vane 1, an impeller 2 and a main shaft 3, wherein a first blade 201 and a second blade 202 are fixedly mounted on the impeller 2, wherein the number of the first blade 201 and the second blade 202 are the same and the first blade 201 and the second blade 202 are spaced apart, the impeller 2 is threadedly connected to the main shaft 3, a cavity is provided in the guide vane 1, the main shaft 3 and the impeller 2 are assembled in the cavity, and the main shaft 3, the impeller 2 and the guide vane 1 are assembled and mounted in a straight-section volute 4.

[0027] Based on a conventional hydraulic turbine, this device features an optimized structural design for the turbine flow path components, improving turbine recovery efficiency while reducing vibration and flow-induced noise. First blades 201 and second blades 202 are fixedly mounted on impeller 2 to form a backward-curved composite impeller. In this application, impeller 2 is a backward-curved composite impeller, with the guide vanes radially fixed within the straight volute.

[0028] The straight-section volute 4 is made of transparent material and is transparent. The transparent straight-section volute 4 replaces the original tapered volute 4, and the water-passing section of the straight-section volute 4 adopts a circular section, which improves the flow performance of the fluid. In addition, the use of the transparent straight-section volute 4 can observe the formation and evolution process of the fluid vortex structure in the straight-section volute 4. Compared with the original turbine volute 4, the sound pressure level of the hydraulic turbine inlet and outlet of the straight-section volute 4 is reduced, the hydrodynamic noise generated inside the turbine is reduced, and the acoustic performance and flow field performance of the turbine inlet and outlet are improved.

[0029] Figure 9 and Figure 10 The figure shows the sound pressure cloud diagram of different shell dipole sources. It can be seen that the high sound pressure level area of ​​the turbine is mainly concentrated at the inlet of the volute 4, and the low sound pressure level area is concentrated at the outlet. During the operation of the turbine, the cross-sectional shape of the volute 4 has a greater impact on the sound pressure level of the turbine outlet. The minimum outlet sound pressure level of the contraction pipe section is 65.3dB, while the minimum outlet sound pressure level of the straight pipe section volute 4 is 45.4dB. Therefore, the straight section volute 4 can reduce the flow noise of the turbine.

[0030] The impeller 2 is fixed with the same number of first blades 201 and second blades 202. The first blades 201 and the second blades 202 are in an arc-shaped structure and both are backward-curved blades. The curvature and length of the first blades 201 are greater than the curvature and length of the second blades 202. The original conventional transparent impeller is replaced with a backward-curved composite impeller with first blades 201 and second blades 202 in this device, wherein the number of first blades 201 and second blades 202 of the impeller 2 is determined by the number of blades on the original impeller. The impeller 2 of this device has the same number of first blades 201 as the number of blades on the original impeller, and then the same number of second blades 202 are added. After adopting the impeller 2 of this device, the flow channel structure of the impeller 2 is improved, the vortex in the flow channel is reduced, and the flow field distribution is more uniform. After numerical calculation, it is found that the hydraulic efficiency of the backward-curved composite impeller model is 3.03% higher than that of the original model. The flow efficiency curve is shown in FIG. Figure 6 On the other hand, with the backward-curved composite impeller, the splitter blades can reduce the dynamic and static interference at the baffle and between the impeller 2 and the straight volute 4, thereby weakening the dipole sound source caused by this, improving the sound pressure level of the hydraulic turbine flow components, and thus achieving the effect of reducing the noise of the hydraulic turbine.

[0031] A through hole 203 is provided at the center of the impeller 2, and an internal thread is provided in the through hole 203. An external thread is provided at the leftmost end of the main shaft 3. The impeller 2 is installed on the thread of the main shaft 3 from the left end of the main shaft 3. The main shaft 3 and the impeller 2 are fixedly connected by threads and then fixed with nuts. A cavity is provided inside the guide vane 1 for placing the impeller 2. The guide vane 1 is inserted into the main shaft 3 from the right end of the main shaft 3 so that the end of the main shaft 3 with the impeller 2 installed is located in the guide vane 1. A gap is provided between the impeller 2 and the guide vane 1 to ensure that the fluid can flow smoothly. The guide vane 1 is fixedly installed in the straight-section volute 4.

[0032] This device adds a guide vane 1 between the straight volute 4 and the impeller 2. This increases the circulation at the impeller 2 inlet and provides a flow-guiding effect. Fluid flows from the outlet of the guide vane 1 into the inlet of the impeller 2, flattening the blade load curve from the inlet to the outlet of the impeller 2 and increasing energy conversion. The dynamic-static interference between the impeller 2 and the volute 4 is a major factor in flow-induced noise in hydraulic turbines. The interference between the dynamic and static rotors shifts from between the volute 4 and the impeller 2 to between the impeller 2 and the guide vane 1. This reduced dynamic-static interference reduces the radial force on the turbine impeller 2, further reducing flow-induced noise within the turbine flow path and the resulting unit vibration. Numerical calculations show that the external sound pressure level is most significantly reduced when the number of blades in the guide vane 1, Z0, equals Z+3 (where z is the number of blades in the original impeller), achieving a 25% reduction compared to the sound pressure level of the original turbine model.

[0033] The number of blades of the original model impeller 2 is Z=6. On this basis, the long and short blades of the original impeller 2 model are optimized. The optimized model impeller 2 has the long and short blade forms of Z=5+5, 6+6, 7+7 and 8+8 respectively ( Figure 5 ), after numerical calculation of the external characteristics of the five models, it was found that the optimal operating points of the five models were at the same flow rate, but the hydraulic efficiency and recoverable head of model Z=6+6 were the highest ( Figure 6 ). In addition, the acoustic field calculation was carried out using the splitter blade impeller 2Z=(6+6) with the best hydraulic performance and the original impeller 2 as the research objects. The results show that: dynamic and static interference is the main cause of flow-induced noise in hydraulic turbines. The splitter blade can weaken the intensity of dynamic and static interference, playing a role in reducing the noise of hydraulic turbines. The noise at the blade frequency is the main factor of the internal and external field noise of hydraulic turbines. In terms of internal field noise, under the optimal working conditions, the splitter blade reduces the sound pressure at the inlet and outlet monitoring points by 6.84dB and 7.24dB at the blade frequency. The sound pressure level at the blade frequency reaches the maximum at the volute 4 baffle and the impeller 2 inlet, while the splitter blade can reduce the sound pressure level at the volute 4 baffle and the impeller 2 inlet ( Figure 7 ); In terms of external noise, under the optimal working conditions, the splitter blades reduce the maximum sound pressure of the hydraulic turbine shell radiation noise and the stadium directional noise by 6.07dB and 5.34dB respectively ( Figure 8 ).

[0034] Working process:

[0035] High-pressure fluid flows into the inlet of the straight-section volute 4, passes through the straight pipe section of the straight-section volute 4, and enters the volute water-passing section. The fluid flowing out of the water-passing section of the straight-section volute 4 enters the guide vane 1. The direction of the blades of the guide vane 1 is the same as that of the blades of the impeller 2. Therefore, after the high-pressure fluid flows out of the outlet of the guide vane 1 and enters the impeller 2, it pushes the turbine impeller 2 to rotate at high speed in a clockwise direction. The impeller 2 is connected to the main shaft via threads. The rotation of the impeller 2 also drives the rotation of the main shaft 3, thereby converting the pressure energy of the fluid into mechanical energy, realizing energy recovery of the high-pressure fluid. Unlike traditional hydraulic turbines, the installation of radial fixed guide vanes 1 and a backward-curved composite impeller can reduce the radial force of the turbine backward-curved composite impeller, reducing the flow-induced noise in the turbine flow path and the resulting unit vibration. The backward-curved composite impeller can effectively reduce the sound pressure at the straight-section volute 1, improving the stability of the unit operation, and can also reduce disc losses and improve the hydraulic efficiency of the turbine.

[0036] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the present invention.

[0037] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements to the technical solutions of the present invention made by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A vibration and noise reduction high-efficiency energy recovery hydraulic turbine device, characterized in that: include: A guide vane (1), an impeller (2) and a main shaft (3); a first blade (201) and a second blade (202) are fixedly mounted on the impeller (2); the first blade (201) and the second blade (202) are the same in number and are spaced apart from each other; the impeller (2) is threadedly connected to the main shaft (3); a cavity is provided in the guide vane (1); the main shaft (3) and the impeller (2) are assembled in the cavity; and the main shaft (3), the impeller (2) and the guide vane (1) are assembled and mounted in a straight-section volute (4).

2. The vibration and noise reduction high-efficiency energy recovery hydraulic turbine device according to claim 1 is characterized in that: The first blade (201) and the second blade (202) are in an arc-shaped structure, and the length of the first blade (201) is greater than the length of the second blade (202).

3. The vibration and noise reduction high-efficiency energy recovery hydraulic turbine device according to claim 2 is characterized in that: A through hole (203) is provided at the center of the impeller (2), and an internal thread is provided in the through hole (203).

4. The vibration and noise reduction high-efficiency energy recovery hydraulic turbine device according to claim 3 is characterized in that: One end of the main shaft (3) is provided with an external thread, and the end of the main shaft (3) provided with the external thread is threadedly connected to the impeller (2) through the through hole (203) and fixed by a nut.

5. The vibration and noise reduction high-efficiency energy recovery hydraulic turbine device according to claim 4 is characterized in that: The guide vane (1) is sleeved with the main shaft (3), and the main shaft (3) and the impeller (2) are located in the cavity inside the guide vane (1).

6. The vibration and noise reduction high-efficiency energy recovery hydraulic turbine device according to claim 1 is characterized in that: The water-passing cross section of the straight-section volute (4) is a circular cross section, and the straight-section volute (4) is a transparent straight-section volute (4).

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