Airfoil for variable geometry current generating water turbine

Technical Field

The invention relates to an ocean current power generation turbine airfoils, in particular to a used for variable-geometry current power generation turbine airfoil of the blade, the turbine against ocean current generation to specially designed special requirements.

Background Art

Ocean current power generation is a novel way of obtaining energy. For sea current power generation is through the water turbine of the flow of sea water, push the hydraulic turbine to rotate, the kinetic energy of the sea water is transformed into mechanical energy of the hydraulic turbine, it is a kind of environmental protection of the, cleaning of the way of obtaining electric power. Turbine blades of this kind of turbine is the most critical part. The turbine blades are concerned, the cross section of the blade airfoil of the turbine is chosen and research is the most direct factor of the mechanical efficiency.

Because the velocity of flow of the ocean currents small, water head and the low, the sea water flow factors such as direction is not determined, so when in the use of ocean current generation, with special requirements of the turbine, such as the general reversible turbine, not only the structure of the hydraulic turbine itself is complicated, and the efficiency is very low. Although some scientists also design the the flow of water can be obtained at a relatively low of the rotational speed of the turbine relatively high, however, because of the strong vibration during the rotation of the hydraulic turbine and the efficiency of its lower, water turbine cannot make this kind of the widespread practical application.

From the working principle analysis, high-efficient variable geometry turbine requirements: the working side, the currents can be in the smaller will be the angle of rotation of the open turbine blade, the blade will be as soon as possible into the working state; and the resistance surface, current can be more easily the operation to the side of the closed turbine blade, in order to reduce the running resistance of the hydraulic turbine. If the selected airfoil commonly used (such as NACA airfoils, RAF-6 airfoils, CLARK airfoils, LS airfoils, Gottingen aerofoil, FAGE & COLLINS airfoils, RHODE   GENESE airfoils, COANDA airfoils, such as airfoil EPPLER), due to the unique geometry of the turbine, blade can not open in a timely manner, even if at a relatively large incidence angle after being opened under the state, the large angle of attack of the ocean current, will very quickly separates from the surface of the blade, the airfoil will be a significant decrease in the lift coefficient, drag coefficient large [...] , turbine efficiency will be reduced greatly, it is very difficult to meet the design requirements. Furthermore, because these vane airfoil no specialized design, the resistance side, the currents under the impetus of the blades is difficult for the closed a relatively short period of time, greatly increase the operation resistance of the hydraulic turbine. Therefore, if it is to achieve the requirement of high-efficiency turbine, it is necessary to the design of the turbine blade.

Content of the invention

The purpose of this invention lies in to the deficiency of the prior art, provide a design used for variable-geometry current power generation turbine blade airfoil, can adapt completely to the characteristics of this kind of turbine, thereby improving the efficiency of the water turbine.

In order to achieve such a purpose, the technical proposal adopted by the invention are as follows:

A used for variable-geometry current power generation turbine airfoil, the maximum thickness of the airfoil is the ratio of the chord length of the airfoil is about: The maximum thickness position is: The maximum camber and airfoil chord ratio is: The maximum camber position is: Wherein, c is the chord length of the wing profile, d is the maximum thickness of the airfoil, the airfoil is f is the maximum camber, and the lower surface of the wing attachment point to the origin of coordinates, in order to the airfoil chord length of position as the X axis in the coordinate system formed by, x_d to the position of the maximum thickness of the airfoil transverse coordinate value, x_f airfoil the maximum camber position to the transverse coordinate value.

The present invention provides the airfoil, in order to make the blade in the resistance of the first side of the hub of the hydraulic turbine as far as possible, in order to reduce the rotational resistance of the hydraulic turbine, the middle section of the airfoil and the lower surface of the surface of the circular arc of the trailing edge, and the surface of the hub corresponding to the adjustment of the diameter of the. Furthermore, the design of the circular arc of the vane can also be opened, current impact blade, turbine can obtain greater torque.

The front edge of the lower surface, in order to make the vane in the expansion side of the opening as soon as possible, the reverse circular arc transition, the leading edge of the blades there is a certain gap of the hub, when the current impact, the blades may be opened under the rotation angle.

In the present invention, the airfoil of the maximum camber to move forward. In this way, when the blade side of the resistance to operation, current shocks on the upper surface of the blade, the blade can be closed as soon as possible, in order to reduce the running resistance of the hydraulic turbine. Furthermore, in order to further reduce resistance, a drop in the camber of the wing profile.

Furthermore, because the trailing edge to the circular arc transition, so the blunt outer edge of the aerofoil of the foreign objects is minimized, and it is easy to process.

To sum up, for the current power generation turbine model airfoil has the following characteristics:

1. The maximum thickness of the aerofoil is about: Camber is:

2. The maximum thickness of the aerofoil position is: Compared with the other wing, the maximum thickness position to move forward, thus the performance of the of the hydraulic turbine can be improved on the whole.

3. The aerofoil design-time, the lower surface of the wing section and the middle section of the surface of the circular arc of the trailing edge, and the surface of the hub corresponding to the adjustment of the diameter of the. Furthermore, the design of the circular arc of the vane can also be opened, current impact blade, turbine can obtain greater torque.

4. The front edge of the lower surface, in order to make the vane in the expansion side of the opening as soon as possible, the reverse circular arc transition, the leading edge of the blades there is a certain gap of the hub, when the current impact, the blades may be opened under the rotation angle.

5. Because the trailing edge to the circular arc transition, so the blunt outer edge of the aerofoil of the foreign objects is minimized, the outer edge of the blunt, the processing of the airfoil is reduced to the minimum.

Description of drawings

Figure 1 to the invention used for variable-geometry ocean current generation schematic diagram of the airfoil shape of the hydraulic turbine.

In the diagram, 1 the upper surface of the wing, 2 the lower surface of the wing, 3 to the mean camber line of the airfoil, the airfoil chord length for C, d is the maximum thickness of the airfoil, the airfoil is f is the maximum camber, and the lower surface of the wing attachment point to the origin of coordinates, in order to the airfoil chord length of position as the X axis in the coordinate system formed by, X_d airfoil maximum thickness of the airfoil transverse coordinate value at, X_f the maximum camber of the airfoil transverse coordinate value of the airfoil.

Mode of execution

In conjuction with the embodiment of the present invention in detail: in the embodiment to the technical proposal of the present invention is implemented under the precondition, provides detailed and specific embodiment of the process of operation, the scope of protection of the present invention, however, is not limited to the following embodiments.

Mode of execution as shown in Figure 1 of this invention, 1 the upper surface of the wing, 2 the lower surface of the wing, 3 to the mean camber line of the airfoil, the airfoil chord length for C, d is the maximum thickness of the airfoil, the airfoil is f is the maximum camber, and the lower surface of the wing attachment point to the origin of coordinates, in order to the airfoil chord length of position as the X axis in the coordinate system formed by, X_d airfoil maximum thickness of the airfoil transverse coordinate value at, X_f the maximum camber of the airfoil transverse coordinate value of the airfoil. The airfoil chord length the example takes as the unit 1, this time, the blade airfoil coordinates as shown in table 1 the column:

Table 1

The blade airfoil of the maximum thickness is about: The maximum thickness position is: Camber is:

The design of this invention, in order to make the blade in the resistance of the first side of the hub of the hydraulic turbine as far as possible, in order to reduce the rotational resistance of the hydraulic turbine, the middle section of the airfoil and the lower surface of the surface of the circular arc of the trailing edge, and the surface of the hub corresponding to the adjustment of the diameter of the. Furthermore, the design of the circular arc of the vane can also be opened, current impact blade, turbine can obtain greater torque.

The front edge of the lower surface, in order to make the vane in the expansion side of the opening as soon as possible, the reverse circular arc transition, the leading edge of the blades there is a certain gap of the hub, when the current impact, the blades may be opened under the rotation angle.

In the present invention, the maximum camber position of the airfoil forward, a side close to the hub, in this way, when the blade side of the resistance to operation, current shocks on the upper surface of the blade, the blade can be closed as soon as possible, in order to reduce the running resistance of the hydraulic turbine. Furthermore, in order to further reduce the operation resistance of the hydraulic turbine, the airfoil is a drop in the maximum camber.

Furthermore, because the trailing edge to the circular arc transition, so the blunt outer edge of the aerofoil of the foreign objects is minimized, and it is easy to process.

The invention offers is used in the variable-geometry turbine airfoil, the following technical effects can be brought about by:

1. When the variable-geometry turbine blade adopts a flat circular arc in the design of the, blade normally in 90° left and right open, and the fully open about 120°. When using the invention the wing section of the, blade in the 70° left and right open, and the left and right 95° fully open, in the one-rotation period, greatly improves the working time of the blade.

2. When the blade adopts a flat plate of the circular arc of the design, the blades usually about 180° begins to be closed, and the completely closed about 360°. When the airfoil is put forward in this invention, the vanes are also 180° left and right begins to be closed, and the completely closed about 280 °, in a rotating cycle, greatly shortens the closing time of the blade, effectively reduces the resistance.

3. Because the trailing edge to the circular arc transition, so the blunt outer edge of the aerofoil of the foreign objects is minimized, the outer edge of the blunt, the processing of the airfoil is reduced to the minimum.