Reducing gate position adjusting mechanism of torsion type pipeline water turbine

Abstract

The invention discloses a torsion type pipeline water turbine damping grid position adjusting mechanism which comprises a conveying pipeline, a sliding groove module and a movable damping grid. A guide through groove is formed in the conveying pipeline and extends in the conveying direction of the conveying pipeline. The sliding groove module is arranged outside the conveying pipeline, the interior of the sliding groove module is communicated with the guide through groove, a variable-pitch spring is arranged in the sliding groove module, and the telescopic direction of the variable-pitch spring is consistent with the extending arrangement direction of the guide through groove; the movable damping screen is arranged in the conveying pipeline in a sliding mode and provided with a connecting rod and a sliding block. One end of the connecting rod penetrates through the guide through groove and then is connected with a sliding block; the sliding block is fixedly connected with one end of a variable pitch spring; when the movable damping screen is scoured by fluid, the variable-pitch spring provides resistance for the movable damping screen so that the movable damping screen can move to the stress balance position. After the scheme is adopted, the self-adaptive adjustment of the position of the rectifying grid can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of water turbine guide vanes, and particularly to a position adjusting mechanism for a torsion type pipeline water turbine guide vane. Background Art

[0002] The guide vane can make the fluid in the flow field evenly distributed and suppress the generation of vortices in the nearby flow field, so as to achieve the effect of improving the fluid condition in the fluid domain. Due to the asymmetric structure of the torsion type impeller and the limitation of the pipeline wall on the fluid in the working environment, compared with the conventional water turbine, the torsion type pipeline water turbine is more likely to generate vortices in the wake flow field and takes longer to dissipate. Therefore, setting a guide vane in the wake flow field that can adjust its position autonomously according to the flow field conditions has important research significance for improving the fluid condition in the wake flow field, suppressing the vibration and noise problems of the pipeline caused by vortices, reducing the head loss in the pipeline, and improving the efficiency of the water turbine.

[0003] It should be noted that since the rectifying effect of the guide vane is related to the relative position between the guide vane and the vortex, when the fluid velocity changes or fluctuates within a certain range, the position of the vortex and the optimal position of the guide vane will also change accordingly. In the existing designs, the guide vane structures are all installed in fixed positions, without considering that when the fluid velocity changes, the fluid condition in the water area will also change accordingly, so the position where the guide vane plays the best rectifying role may also change. For the fluid from the vortex center to the impeller, because it has just passed through the impeller, its velocity is small, the flow field is more disordered, and this area is close to the impeller. The vortices generated in this area are likely to have an adverse effect on the operation of the impeller, and this phenomenon is more obvious for the torsion type impeller; downstream of the vortex center, the vortices gradually dissipate and the flow field tends to be stable. Therefore, placing the guide vane at a position slightly upstream near the vortex center can better play the rectifying role.

[0004] Secondly, the cross-sectional shape of the guide vane blades in the existing research is all rectangular. While it plays a rectifying role in the fluid, vortices will be generated on the blade surface due to the boundary layer separation phenomenon, resulting in water energy loss. Therefore, in order to suppress this part of the water energy loss and further improve the energy utilization efficiency, how to change the shape of the guide vane blades for optimization also belongs to an important research direction. Summary of the Invention

[0005] The purpose of the present invention is to provide a position adjusting mechanism for a torsion type pipeline water turbine guide vane to meet the requirement of self-adaptive adjustment of the guide vane position.

[0006] To solve the above technical problems, the present invention provides a position adjustment mechanism for the rectifying grid of a torsion type pipe water turbine, which includes a conveying pipe, a sliding groove module, and a movable rectifying grid; a guiding through groove is provided on the conveying pipe, and the guiding through groove extends along the conveying direction of the conveying pipe; the sliding groove module is arranged outside the conveying pipe, the inside of the sliding groove module is connected to the guiding through groove, a variable pitch spring is arranged inside the sliding groove module, and the telescopic direction of the variable pitch spring is consistent with the extending direction of the guiding through groove; the movable rectifying grid is slidably arranged inside the conveying pipe, and the movable rectifying grid is provided with a connecting rod and a sliding block; one end of the connecting rod passes through the guiding through groove and is connected with the sliding block; the sliding block is fixedly connected with one end of the variable pitch spring; when the movable rectifying grid is washed by fluid, the variable pitch spring is used to provide resistance for the movable rectifying grid, so that the movable rectifying grid moves along the guiding through groove to a force balance position.

[0007] In one embodiment, a guiding rod is arranged inside the sliding groove module, the extending direction of the guiding rod is consistent with the extending direction of the guiding through groove, and the variable pitch spring is sleeved outside the guiding rod.

[0008] In one embodiment, a perforation for one end of the guiding rod to pass through is provided on the sliding block, and the variable pitch spring is compressed between the sliding block and the other end of the guiding rod.

[0009] In one embodiment, one end of the guiding rod passes through the sliding block and extends outside the sliding groove module, and is connected with a pre-tightening force adjusting knob; the other end of the guiding rod is threadedly connected with a pre-tightening force adjusting block, and a part of the pre-tightening force adjusting block is slidably installed inside the guiding through groove, so that a limiting guiding assembly structure is formed between the pre-tightening force adjusting block and the guiding through groove; the variable pitch spring is compressed between the sliding block and the pre-tightening force adjusting block.

[0010] In one embodiment, the pitch at both ends of the variable pitch spring is smaller than the pitch in the middle thereof.

[0011] In one embodiment, the movable rectifying grid includes a plurality of rectifying blades, and the airfoil of the rectifying blade is the NACA0020 airfoil.

[0012] In one embodiment, the connecting rod is connected between the end of the rectifying blade and the sliding block.

[0013] The beneficial effects of the present invention are as follows:

[0014] 1. The NACA0020 airfoil profile with better fluid performance is adopted to replace the conventional rectangular blade profile, improving the fluid performance of the movable rectifying grid itself.

[0015] 2. Set a movable rectifying grid according to the position of the eddy current, providing a basis for the setting position of the movable rectifying grid, and obtaining that the optimal setting position of the movable rectifying grid under this design is upstream of the center of the eddy current.

[0016] 3. According to the variation law of the eddy current position when the flow velocity in the conveying pipeline changes, design an adjustment scheme for the movable rectifying grid to move downstream of the impeller when the flow velocity increases and move closer to the impeller when the flow rate decreases.

[0017] 4. Use a variable pitch spring to adjust the movable rectifying grid. Due to the characteristic that the stiffness coefficient of the variable pitch spring increases with the increase of the compression amount, the movable rectifying grid can be normally adjusted under the working conditions of small flow velocity changes. In the case of large fluctuations, it can increase the elastic force to ensure that the movable rectifying grid is upstream of the center of the eddy current while suppressing the vibration of the movable rectifying grid in the fluid and improving the stability. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0019] Figure 1 is a schematic structural diagram provided by an embodiment of the present invention;

[0020] Figure 2 is Figure 1 a cross-sectional structural diagram of

[0021] Figure 3 is Figure 1 an application scenario diagram of

[0022] Figure 4 is Figure 1 a schematic structural diagram of the movable rectifying grid of

[0023] The reference numerals are as follows:

[0024] 10, conveying pipeline; 11, guiding through groove;

[0025] 20, sliding groove module; 21, variable pitch spring; 22, guiding rod; 23, slider; 24, pre-tightening force adjusting knob; 25, pre-tightening force adjusting block;

[0026] 30, movable rectifying grid; 31, connecting rod; 32, sliding block; 321, perforation; 33, rectifying blade;

[0027] 40, impeller. Detailed implementation mode

[0028] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention.

[0029] By performing a fluid analysis on the water turbine, it can be obtained that there is a certain correlation law between the fluid velocity and the eddy current distribution in its wake flow field: the flow field velocity from the eddy current center to the impeller is relatively small, and downstream of the eddy current center, the eddy current gradually becomes stable and its velocity gradually increases. By analyzing the law of the resistance suffered by an object in a fluid, it can be obtained that the resistance suffered by an object in a fluid is proportional to the square of the fluid velocity. From this, it can be obtained that the resistance suffered by the object in the upstream of the eddy current is less than that in the downstream of the eddy current.

[0030] The position adjustment mechanism of the torsion type pipe water turbine rectifying grid designed in this article is as Figure 1 shown, which mainly includes a movable rectifying grid 30, a sliding groove module 20, and a conveying pipe 10. In order to avoid excessive influence on the flow of the fluid in the conveying pipe 10, the sliding groove module 20 is installed on the outer wall of the conveying pipe 10, and the position of the movable rectifying grid 30 is fixed through the wall surface of the conveying pipe 10 and the sliding groove module 20, restricting its sliding within a certain range. A spring is installed in the sliding groove module 20 to provide a thrust for the movable rectifying grid 30, so as to achieve the purpose of the movable rectifying grid 30 adjusting its position adaptively according to the fluid situation.

[0031] According to the force analysis of the movable rectifying grid 30, it can be obtained that for the movable rectifying grid 30 to reach an equilibrium state at a certain position in the conveying pipe 10, it is necessary to make the elastic force F of the spring s equal to the resistance F suffered by the movable rectifying grid 30 in the water flow l , that is, to satisfy Equation (1). In actual working conditions, the water flow density ρ, the projected area S of the movable rectifying grid 30 r and the resistance coefficient C r in Equation (2) have all been determined. Therefore, the resistance F suffered by the movable rectifying grid 30 in the water flow l is determined by the water flow velocity v. Considering the characteristics of the force change of the movable rectifying grid 30 before and after the eddy current, the spring used in this study is a variable pitch spring 21, which has the characteristic that its stiffness coefficient increases with the increase of the force. From Equation (3), it can be obtained that during the compression process of the variable pitch spring 21, its stiffness coefficient k and the deformation amount Δx increase simultaneously. When the variable pitch spring 21 is compressed beyond a certain position, the elastic force generated by the variable pitch spring 21 will increase sharply.

[0032] Therefore, the design principle of the adjustment mechanism is: when the water flow velocity v changes within a small range, F lalso changes accordingly, which makes the two sides of the equal sign in Equation (1) no longer equal. At this time, to achieve a new balance, the change in the spring constant k is relatively small, mainly due to the change in the spring deformation Δx, which simultaneously drives the movable flow rectifying grid 30 to move, causing the elastic force F s generated by the variable pitch spring 21 l to be equal to the water flow resistance F s again, and the movable flow rectifying grid 30 reaches a balance at the new position. If the flow velocity v fluctuates greatly, causing the movable flow rectifying grid 30 to tend to move downstream of the eddy center, due to the characteristics of the variable pitch spring 21, the spring constant k also increases accordingly. At this time, the elastic force F

[0033] generated by the variable pitch spring 21 s (1)

[0034]

[0035] F s = kΔx (3)

[0036] In the formula: F l is the resistance suffered by the movable flow rectifying grid 30 in the water flow, N; F s is the elastic force exerted by the variable pitch spring 21 on the movable flow rectifying grid 30, N; ρ is the water flow density, kg / m 3 ; v is the water flow velocity, m / s; S r is the projected area of the movable flow rectifying grid 30 perpendicular to the water flow velocity direction, m 2 ; C r is the resistance coefficient of the movable flow rectifying grid 30 in the water; k is the spring constant of the variable pitch spring 21, N / m; Δx is the deformation of the variable pitch spring 21, m.

[0037] Specifically, the implementation example of the above-mentioned torsion type pipe water turbine flow rectifying grid position adjusting mechanism is as follows Figures 1 to 4As shown in the figure, it includes a conveying pipeline 10, a sliding groove module 20 and a movable flow rectifying grid 30; a guiding through groove 11 is provided on the conveying pipeline 10, and the guiding through groove 11 extends along the conveying direction of the conveying pipeline 10; the sliding groove module 20 is arranged outside the conveying pipeline 10, the inside of the sliding groove module 20 is communicated with the guiding through groove 11, a variable pitch spring 21 is arranged inside the sliding groove module 20, and the telescopic direction of the variable pitch spring 21 is consistent with the extending direction of the guiding through groove 11; the movable flow rectifying grid 30 is slidably arranged in the conveying pipeline 10, and the movable flow rectifying grid 30 is provided with a connecting rod 31 and a sliding block 32; one end of the connecting rod 31 passes through the guiding through groove 11 and is connected with a sliding block 32; the sliding block 32 is fixedly connected with one end of the variable pitch spring 21; when the movable flow rectifying grid 30 is washed by fluid, the variable pitch spring 21 is used to provide resistance for the movable flow rectifying grid 30, so that the movable flow rectifying grid 30 moves along the guiding through groove 11 to a force balance position.

[0038] As Figure 1 and Figure 2 shown in the figure, in this embodiment, a guiding rod 22 is arranged inside the sliding groove module 20, the extending direction of the guiding rod 22 is consistent with the extending direction of the guiding through groove 11, and the variable pitch spring 21 is sleeved outside the guiding rod 22.

[0039] After adopting this setting method, the guiding rod 22 can fix the installation position of the variable pitch spring 21, ensuring that the variable pitch spring 21 can only expand and contract axially along the guiding rod 22.

[0040] As Figure 3 and Figure 4 shown in the figure, in this embodiment, a perforation 321 for one end of the guiding rod 22 to pass through is provided on the sliding block 32, and a variable pitch spring 21 is compressed between the sliding block 32 and the other end of the guiding rod 22.

[0041] After adopting this setting method, once the variable pitch spring 21 generates telescopic deformation, a corresponding acting force will also act on the sliding block 32, thereby driving the sliding block 32 to move back and forth on the guiding rod 22. Therefore, once the sliding block 32 moves, it actually realizes the synchronous movement of the sliding block 32 and the movable flow rectifying grid 30.

[0042] Moreover, at this time, the sliding block 32 is also connected with a slider 23, and the slider 23 is used for the radial positioning of the movable flow rectifying grid 30.

[0043] As Figures 1 to 3As shown, in this embodiment, one end of the guide rod 22 passes through the sliding block 32 and extends outside the sliding groove module 20, and is connected with a pre-tightening force adjusting knob 24; the other end of the guide rod 22 is threadedly connected with a pre-tightening force adjusting block 25, and a part of the pre-tightening force adjusting block 25 is slidably installed in the guide through groove 11, so as to form a limit guiding assembly structure between the pre-tightening force adjusting block 25 and the guide through groove 11; the variable pitch spring 21 is compressed between the sliding block 32 and the pre-tightening force adjusting block 25.

[0044] After adopting this setting method, once the guide rod 22 is controlled to rotate by itself by using the pre-tightening force adjusting knob 24, the guide rod 22 and the pre-tightening force adjusting block 25 will essentially form a state of screw drive, and the linear reciprocating movement control of the pre-tightening force adjusting block 25 can be realized, so as to realize the adjustment of the initial compression amount of the variable pitch spring 21 to meet the application requirements in different situations.

[0045] As Figure 2 shown, in this embodiment, the pitch at both ends of the variable pitch spring 21 is smaller than the pitch in the middle thereof.

[0046] As Figure 4 shown, in this embodiment, the movable rectifying grid 30 is provided with a plurality of rectifying blades 33, and the airfoil of the rectifying blade 33 is the NACA0020 airfoil.

[0047] After adopting this setting method, the generation of wall surface vortices of the movable rectifying grid 30 itself can be suppressed by using the NACA0020 airfoil.

[0048] As Figure 4 shown, in this embodiment, the connecting rod 31 is connected between the end of the rectifying blade 33 and the sliding block 32.

[0049] When applying the above embodiment, as Figures 1 to 4 shown, its specific working principle is as follows:

[0050] When in the low water consumption period and the flow rate in the conveying pipeline 10 is small, a movable rectifying grid 30 and a sliding groove module 20 are installed on the conveying pipeline 10. The pre-tightening force adjusting knob 24 is adjusted according to the flow velocity in the conveying pipeline 10. The pre-tightening force adjusting knob 24 drives the guide rod 22 to rotate, and makes the pre-tightening force adjusting block 25 threadedly connected to the guide rod 22 move along the direction of the guide rod 22. At the same time, the change in the position of the pre-tightening force adjusting block 25 compresses or stretches the variable pitch spring 21. After the variable pitch spring 21 deforms, it exerts an elastic force on the movable rectifying grid 30, and the movable rectifying grid 30 is also subjected to fluid resistance in the conveying pipeline 10. The movable rectifying grid 30 reaches equilibrium under the combined action of the resistance and the elastic force. The equilibrium position during the low water consumption period is taken as the initial position of the movable rectifying grid 30. When the water demand increases and the water flow velocity increases, the intensity of the eddy current generated downstream of the impeller 40 increases and the center of the eddy current moves downstream of the impeller 40. Due to the increase in the water flow velocity, the resistance received by the movable rectifying grid 30 also increases, which causes it to move downstream of the impeller 40 and compress the variable pitch spring. Therefore, the elastic force generated by the variable pitch spring 21 also begins to increase. After the elastic force generated by the variable pitch spring 21 is equal to the water flow resistance again, the movable rectifying grid 30 moves to a new equilibrium position. At the same time, if the flow velocity fluctuates greatly and the movable rectifying grid 30 has a tendency to move downstream of the eddy current center, due to the characteristics of the variable pitch spring 21, its stiffness coefficient also increases. At this time, the elastic force generated by the variable pitch spring 21 will rise sharply, thereby preventing the movable rectifying grid 30 from continuing to move downstream and keeping it in the upper-middle position of the eddy current. This adjustment method can adapt to the load changes at different flow velocities, effectively suppress vibration and improve stability, and make the movable rectifying grid 30 always stay near the eddy current center and upstream, and automatically adjust with the change of the flow velocity within a certain range, so as to achieve the best rectifying effect.

[0051] The above is the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present invention.

Claims

1. A rectifying grid position adjusting mechanism for a torsional pipeline water turbine, characterized in that it includes a conveying pipeline, a sliding groove module and a movable rectifying grid; a guiding through groove is provided on the conveying pipeline, and the guiding through groove extends along the conveying direction of the conveying pipeline; the sliding groove module is arranged outside the conveying pipeline, the inside of the sliding groove module is connected to the guiding through groove, a variable pitch spring is arranged inside the sliding groove module, and the telescopic direction of the variable pitch spring is consistent with the extending direction of the guiding through groove; the movable rectifying grid is slidably arranged in the conveying pipeline, and the movable rectifying grid is provided with a connecting rod and a sliding block; one end of the connecting rod passes through the guiding through groove and is connected with the sliding block; the sliding block is fixedly connected with one end of the variable pitch spring; when the movable rectifying grid is flushed by fluid, the variable pitch spring is used to provide resistance for the movable rectifying grid, so that the movable rectifying grid moves along the guiding through groove to a force balance position.

2. The rectifying grid position adjusting mechanism for a torsional pipeline water turbine according to claim 1, characterized in that a guiding rod is arranged in the sliding groove module, the extending direction of the guiding rod is consistent with the extending direction of the guiding through groove, and the variable pitch spring is sleeved outside the guiding rod.

3. The rectifying grid position adjusting mechanism for a torsional pipeline water turbine according to claim 2, characterized in that a perforation for one end of the guiding rod to pass through is provided on the sliding block, and the variable pitch spring is compressed between the sliding block and the other end of the guiding rod.

4. The rectifying grid position adjusting mechanism for a torsional pipeline water turbine according to claim 3, characterized in that one end of the guiding rod passes through the sliding block and extends outside the sliding groove module, and is connected with a pre-tightening force adjusting knob; the other end of the guiding rod is threadedly connected with a pre-tightening force adjusting block, and a part of the pre-tightening force adjusting block is slidably installed in the guiding through groove, so as to form a limiting guiding assembly structure between the pre-tightening force adjusting block and the guiding through groove; the variable pitch spring is compressed between the sliding block and the pre-tightening force adjusting block.

5. The rectifying grid position adjusting mechanism for a torsional pipeline water turbine according to claim 1, characterized in that the pitch at both ends of the variable pitch spring is smaller than the pitch in the middle thereof.

6. The rectifying grid position adjusting mechanism for a torsional pipeline water turbine according to claim 1, characterized in that the movable rectifying grid includes a plurality of rectifying blades, and the airfoil of the rectifying blade is NACA0020 airfoil.

7. The rectifying grid position adjusting mechanism for a torsional pipeline water turbine according to claim 6, characterized in that the connecting rod is connected between the end of the rectifying blade and the sliding block.

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