CN107401469A - A kind of two-way rotary wheel of water turbine of low water head shaft tubular - Google Patents

Abstract

The invention discloses a kind of two-way rotary wheel of water turbine of low water head shaft tubular, it is made up of blade, runner boss, draft cone three parts, circumferentially be evenly arranged with the blade that multiple sections are symmetrical airfoil in runner boss, blade to be shaped as thick middle both sides thin, and blade minimum thickness b₁With maximum gauge b₂The ratio between be 0.28~0.35, the upper and lower surface of blade is spatial warping face, and the initial laying angle of blade is 66 °, and adjusted value is between ± 3 °.The present invention can not only two-way operation, and have preferable energy conversion performance, while cost is lower.

Description

A low-head shaft cross-flow two-way water turbine runner

technical field

The invention relates to a low-head shaft cross-flow two-way water turbine runner, which belongs to the technical field of energy utilization.

Background technique

At present, as the high-head hydropower resources in all countries in the world are gradually exhausted, all countries are turning their attention to low-head hydropower resources, such as ocean tidal energy. After entering the 21st century, due to the impact of the sharp rise in oil prices and the pressure of carbon dioxide emission reduction, tidal energy, as a clean and renewable energy, has once again been valued by countries all over the world. Tidal power generation is the process of using the potential energy of the water level difference generated by the rising and falling tides to generate electricity, and converting the energy of rising and falling tides into mechanical energy and converting it into electrical energy (power generation). Specifically, a water-retaining dam is built in a bay or a tidal estuary to separate the bay or estuary from the ocean to form a reservoir, and then install a hydroelectric generator set in the dam or dam house, and then use the rise and fall of the sea level when the tide rises and falls, The seawater is passed through the turbine to turn the hydroelectric generating set to generate electricity. Due to the relatively low water head of tidal power generation, tubular turbines are mainly used. There are only a very small number of small-capacity units in operation for vertical shaft tubular units in my country. The main reason is the design of the flow channel of vertical shaft tubular units, the overall structural type of the unit, the connection mode of the speed increaser and the double adjustment structure. The lack of in-depth research and design of key technologies such as how to solve the arrangement of the oil receiver has resulted in this kind of shaft with simple structure, convenient installation and maintenance, excellent hydraulic performance, and low cost (20% to 60% lower than the cost of the bulb tubular unit) The tubular unit has not been developed, popularized and used. Therefore, it is an urgent task and far-reaching significance to carry out research on new shaft tubular hydroelectric generating units, reduce the construction and operation costs of tidal power stations, and promote the development of tidal power stations.

Contents of the invention

The present invention aims at the shortcomings of the above problems, and proposes a low-head vertical shaft through-flow bidirectional water turbine runner and supporting electromechanical devices and flow channels. The water turbine can work in both directions, and has better energy conversion performance and low cost.

In order to solve the problems of the technologies described above, the technical solution of the present invention is:

A low-head shaft cross-flow two-way water turbine runner, including blades, runner hub and discharge cone, a plurality of blades with symmetrical airfoil cross-sections are evenly arranged along the circumference of the runner hub, and the water discharge of the runner hub A drain cone is installed on one side; the shape of the blade is thick in the middle and thin on both sides, and the ratio of the minimum thickness b1 to the maximum thickness b2 of the blade is 0.28-0.35;

The runner is installed at the end of the main shaft of the water turbine, and the main shaft is connected with the water turbine and the generator in sequence, and transmits the mechanical energy of the water turbine to the generator; the runner is installed on the water outlet side of the water turbine, and the movable guide vanes are installed In front of the turbine inlet on the water inlet side;

The upper and lower surfaces of the blade are both space distortion surfaces, and the three-dimensional coordinates of the feature points on the six spatial sections of the extracted blade are as follows,

Among them, F1-F6 are 6 space sections, U represents the upper surface, D represents the lower surface, and x, y, z are three-dimensional coordinates. There are 3 aforementioned blades.

The initial placement angle of the aforementioned blades is 66°, and the adjustment value is between ±3°.

The aforementioned ratio of runner blade height h to runner diameter d is 0.26.

The aforementioned ratio of runner hub diameter d ₀ to runner diameter d is 0.35.

The foregoing curve fitting is carried out to the feature points of the extracted leaves, and 12 fitted feature curves are obtained as follows:

F1-U: yu=-0.0082x ² -2.9442x+248.56

F1-D: yd=-0.0054x ² -3.1782x+166.54

F2-U: yu=-0.0065x ² -2.4396x+186.14

F2-D: yd=-0.0039x ² -2.6669x+100.82

F3-U: yu=-0.0052x ² -1.9769x+121.46

F3-D: yd=-0.0029x ² -2.1922x+35.953

F4-U: yu=-0.0042x ² -1.5854x+55.929

F4-D: yd=-0.0022x ^2-1.7877x -27.867

F5-U: yu=-0.0034x ^2-1.2492x -10.296

F5-D: yd=-0.0017x ² -1.439x-90.913

F6-U: yu=-0.0027x ^2-0.956x -77.134

F6-D: yd=-0.0013x2-1.1343x ^- 153.4.

When the aforementioned runner is manufactured, firstly, the diameter d of the runner to be used is determined according to the water head and flow rate of the two-way tidal power station; then, according to the determined runner size, according to the ratio h of the runner blade height h to the runner diameter d: d=0.26, the ratio relationship d 0 between the hub diameter d ₀ of the runner and the diameter d of the runner d ₀ : d=0.35, the overall geometry of the runner is scaled according to the corresponding size; finally, for the main airfoil of the runner blade, according to the The overall fitting of the above feature points, or the fitting from line to surface according to the characteristic curve, the three-dimensional model of the overall runner is modeled before the factory casting production.

A speed increaser is arranged between the aforementioned water turbine and the generator.

The present invention has the following advantages:

1. The water turbine generates electricity in two directions, and the energy conversion efficiency is high, which improves the utilization rate of tidal energy and improves the efficiency of tidal power stations.

2. The overall cost is relatively cheap.

3. The runner can change the blade placement angle according to the change of water head and flow, so as to meet the appropriate operating conditions and ensure that the unit operates in the high-efficiency zone.

4. A speed increaser is installed between the water turbine and the generator, which reduces the volume and cost of the generator, and also reduces the excavation volume of earthworks.

Description of drawings

Fig. 1 is a two-dimensional model diagram of a low-head shaft cross-flow two-way water turbine of the present invention, wherein Fig. 1 (b) is a top view of 1 (a);

Fig. 2 is a three-dimensional model diagram of a two-way shaft tubular water turbine;

Fig. 3 is the three-dimensional model figure of runner, and wherein, Fig. 3 (b) is the right side view of Fig. 3 (a);

Fig. 4 is the placement angle of the runner blade;

Fig. 5 is the vertical runner blade model and blade cross-sectional view;

Fig. 6 is a horizontal runner blade model and a cross-sectional view of the blade, wherein Fig. 6(a) is a three-dimensional model diagram, and Fig. 6(b) is a schematic diagram of six sections F1 to F6 on 6(a);

Figure 7 is the characteristic curve on the 6 sections of Figure 6(b); (a) is the characteristic curve on F1, (b) is the characteristic curve on F2, (c) is the characteristic curve on F3, (d) is the characteristic curve on F4, (e) is the characteristic curve on F5, and (f) is the characteristic curve on F6.

detailed description

The present invention will be further described below. The following examples are only used to illustrate the technical solution of the present invention more clearly, but not to limit the protection scope of the present invention.

As shown in Fig. 3 (a) and (b), the runner of the low-head shaft cross-flow two-way water turbine of the present invention is installed on the main shaft end of the water turbine, including blade 81, runner hub 82 and water discharge cone 83, wherein, along A plurality of blades 81 with symmetrical airfoils in section are uniformly arranged in the circumferential direction of the runner hub 82 , and a water discharge cone 83 is installed on the water discharge side of the runner hub.

The ratio of runner blade height h to runner diameter d is 0.26, and the ratio of runner hub diameter d ₀ to runner diameter d is 0.35.

As shown in Figure 4, the initial placement angle of the blade is 66°, and the adjustment value is between ±3°.

As shown in Fig. 5 and Fig. 6(a) and (b), the shape of the blade is thick in the middle and thin on both sides, and the ratio of the minimum thickness b1 to the maximum thickness b2 of the blade is 0.28-0.35.

Preferably, there are three blades.

During application, the rotor speed can reach 200-300 rpm.

Figure 5 and Figure 6 are the vertical and horizontal models and blade cross-sectional views of the runner blades respectively. The upper and lower surfaces of the blades are space-distorted surfaces. The three-dimensional coordinates of the feature points on (b)) are shown in Table 1 below.

Table 1 The three-dimensional coordinates of the feature points on the space section of the blade

Among them, F1-F6 are 6 space sections, U represents the upper surface, D represents the lower surface, and x, y, z are three-dimensional coordinates.

According to the three-dimensional coordinates of the feature points, in order to ensure the hydraulic performance and structural strength of the runner, curve fitting is performed on the extracted feature points. The fitted curve ensures smoother airfoil curve and better hydraulic performance of the runner. The 12 fitting curves are shown in Figure 7(a)-(f),

The equation is as follows:

F1-U: yu=-0.0082x ² -2.9442x+248.56

F1-D: yd=-0.0054x ² -3.1782x+166.54

F2-U: yu=-0.0065x ² -2.4396x+186.14

F2-D: yd=-0.0039x ² -2.6669x+100.82

F3-U: yu=-0.0052x ² -1.9769x+121.46

F3-D: yd=-0.0029x ² -2.1922x+35.953

F4-U: yu=-0.0042x ² -1.5854x+55.929

F4-D: yd=-0.0022x ^2-1.7877x -27.867

F5-U: yu=-0.0034x ^2-1.2492x -10.296

F5-D: yd=-0.0017x ² -1.439x-90.913

F6-U: yu=-0.0027x ^2-0.956x -77.134

F6-D: yd=-0.0013x ² -1.1343x-153.4

In engineering, the wooden model diagram is used to express the blades of the turbine runners, and to control the machining accuracy and measurement accuracy of the blades.

The low-head vertical shaft cross-flow two-way water turbine runner of the present invention has supporting electromechanical devices, as shown in Figure 1 (a), (b) and Figure 2, including generator 9, movable guide vane 7, main shaft 6 and water turbine, wherein , the main shaft 6 is sequentially connected with the water turbine and the generator 9, and transmits the mechanical energy of the water turbine to the generator. The runner 8 is installed on the water outlet side of the water turbine, and the movable guide vane 7 is installed in front of the water turbine inlet on the water inlet side of the runner. A speed increaser 10 is arranged between the water turbine and the generator.

The low-head vertical shaft tubular flow two-way water turbine adopting the runner of the present invention is placed in the matching flow channel, as shown in Figures 1 and 2, including the water inlet section 1, the shaft section 2, the guide vane section 3, the runner section 4 and the draft tube paragraph 5. Wherein, the generator and the speed increaser are arranged in the shaft 22 of the shaft section 2, and the shaft 22 is located in the shaft section flow channel 21 of the shaft section 2; the movable guide vane 7 is arranged in the guide vane section 3; The generator and the generator transmit the mechanical energy of the water turbine to the speed increaser and the generator; the water turbine is arranged in the runner chamber of the runner section 4; the runner 8 is installed at the end of the main shaft of the water turbine. The draft tube includes a circular straight cone section 51 of the draft tube, a circular-to-rectangular diffuser section 52 and a rectangular outlet 53 of the draft tube.

Working principle of the present invention: the present invention is applicable to bidirectional tidal power stations. After the high tide begins, the sluice is closed when the tide water level in the outer sea is nearly equal to the water level in the reservoir. As the tidal water level rises, a drop between high outside and low inside is formed. When the water head exceeds the minimum working head allowed by the turbine, the turbine is put into operation and starts to generate electricity. At this time, the water flows from the outer sea to the reservoir, causing the water level of the reservoir to rise, but the tide rises faster. Therefore, the working water head is also increasing until the moment of climax. When the tide is low, the tide level drops, the reservoir water level is at a high water level, and the water head falls to the lowest working head allowed by the turbine, and the turbine stops generating electricity. As shown in Figure 2, when generating power in the forward direction, the water flow flows from the shaft section 2 to the draft tube section 5, and when passing through the turbine, the water flow drives the runner to rotate, converting the kinetic energy of the water flow into mechanical energy, and then converting the mechanical energy into electrical energy through the generator. The direction of water flow is opposite during reverse power generation.

During the type selection, manufacture, installation and power generation of the main dimensions of the present invention, the following requirements shall be followed:

(1) According to the water head and flow rate of the two-way tidal power station, determine the diameter d of the applied runner; then according to the determined runner size, according to the ratio relationship between the blade height h of the water turbine and the diameter d of the runner, the diameter of the runner hub d ₀ and The ratio relationship of the turbine diameter d scales the overall geometry of the runner according to the corresponding size.

(2) For the main airfoil of the runner blade, carry out integral fitting according to the characteristic points provided by the present invention, also can carry out the fitting from line to surface according to several characteristic curves, after the model three-dimensional modeling of integral runner is promptly Factory casting production can be carried out, and the final finished product of the runner needs to be polished. The smoothness and smoothness of the surface also have an important impact on the running efficiency of the runner.

In the present invention, since the blades of the water turbine adopt a symmetrical airfoil, it can generate electricity under different working conditions in the forward and reverse directions of the water flow, and its energy conversion performance is high; It can generate electricity when the tide is falling, and its power generation time and power generation are more than that of the one-way tidal power station, which can make full use of tidal energy. The direction of the water flow in the two power generation is opposite, requiring the water turbine to work in both directions, and the forward and reverse work of the water turbine can have better energy conversion performance, so as to obtain as much tidal energy as possible, improve the utilization rate of tidal energy, and improve the efficiency of tidal power stations . In actual work, the energy conversion efficiency of the runner can reach more than 80% when generating power in the forward and reverse directions. When the water head is 2 meters, the optimal efficiency of the runner is 88% when generating electricity in the forward direction, and 81.5% when generating electricity in the reverse direction.

At the same time, the overall cost of hydropower station development is relatively cheap, and the cost of the runner of the present invention is 20% to 60% lower than that of the more commonly used bulb tubular unit at present.

Since the initial placement angle of the blades is 66°, and the adjustment value is between -3° and 3°, the runner can change the placement angle of the blades according to the change of water head and flow to meet the appropriate operating conditions and ensure that the unit is in the high-efficiency area run.

A speed increaser is arranged between the water turbine and the generator, thereby reducing the volume and cost of the generator, and also reducing the excavation volume of earthworks.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the technical principle of the present invention, some improvements and modifications can also be made. It should also be regarded as the protection scope of the present invention.

Claims (8)

1. a low-head shaft cross-flow two-way water turbine runner, is characterized in that, comprises blade, runner hub and discharge cone, is evenly provided with the blade that a plurality of sections are symmetrical airfoil along the circumferential direction of runner hub, in A discharge cone is installed on the discharge side of the runner hub; the shape of the blade is thick in the middle and thin on both sides, and the ratio of the minimum thickness b1 to the maximum thickness b2 of the blade is 0.28-0.35; The runner is installed at the end of the main shaft of the water turbine, and the main shaft is connected with the water turbine and the generator in sequence, and transmits the mechanical energy of the water turbine to the generator; the runner is installed on the water outlet side of the water turbine, and the movable guide vanes are installed In front of the turbine inlet on the water inlet side; The upper and lower surfaces of the blade are both space distortion surfaces, and the three-dimensional coordinates of the feature points on the six spatial sections of the extracted blade are as follows, Among them, F1-F6 are 6 space sections, U represents the upper surface, D represents the lower surface, and x, y, z are three-dimensional coordinates. 2. The runner of a low-head vertical shaft cross-flow two-way water turbine according to claim 1, wherein there are three blades. 3. The runner of a low-head vertical shaft cross-flow two-way water turbine according to claim 1, wherein the initial placement angle of the blades is 66°, and the adjustment value is between ±3°. 4. The runner of a low-head vertical shaft cross-flow two-way water turbine according to claim 1, wherein the ratio of the runner blade height h to the runner diameter d is 0.26. 5. The runner of a low-head shaft cross-flow two-way water turbine according to claim 1, wherein the ratio of the runner hub diameter d ₀ to the runner diameter d is 0.35. 6. a kind of low-head vertical shaft cross-flow two-way water turbine runner according to claim 1, is characterized in that, curve fitting is carried out to the feature point of the blade that extracts, obtains 12 fitting characteristic curves as follows: F1-U: yu=-0.0082x ² -2.9442x+248.56 F1-D: yd=-0.0054x ² -3.1782x+166.54 F2-U: yu=-0.0065x ² -2.4396x+186.14 F2-D: yd=-0.0039x ² -2.6669x+100.82 F3-U: yu=-0.0052x ² -1.9769x+121.46 F3-D: yd=-0.0029x ² -2.1922x+35.953 F4-U: yu=-0.0042x ² -1.5854x+55.929 F4-D: yd=-0.0022x ^2-1.7877x -27.867 F5-U: yu=-0.0034x ^2-1.2492x -10.296 F5-D: yd=-0.0017x ² -1.439x-90.913 F6-U: yu=-0.0027x ^2-0.956x -77.134 F6-D: yd=-0.0013x2-1.1343x ^- 153.4. 7. The runner of a low-head shaft cross-flow two-way water turbine according to claim 6, wherein, when the runner is manufactured, the diameter d of the runner to be used is firstly determined according to the water head and the flow rate of the two-way tidal power station; Then according to the determined runner size, according to the ratio relationship h of runner blade height h to runner diameter d: d=0.26, the ratio relationship d ₀ of runner hub diameter d ₀ to runner diameter d: d=0.35, The overall geometry of the runner is scaled according to the corresponding size; finally, for the main airfoil of the runner blade, the overall fitting is carried out according to the characteristic points, or the fitting from line to surface is carried out according to the characteristic curve, and the overall runner blade is After three-dimensional modeling of the model, the factory casting production is carried out. 8 . The runner of a low-head shaft through-flow two-way water turbine according to claim 1 , wherein a speed increaser is arranged between the water turbine and the generator.