JP5670591B1 - Axial impeller and turbine - Google Patents

Abstract

An axial-flow impeller and a turbine capable of improving output efficiency without increasing the size are provided. A plurality of rotor blades 12 are arranged at equal angular intervals around a head 11 and receive a fluid flow along the direction of the central axis of the head 11 so as to be rotatable around the central axis of the head 11. It has been. A plurality of protrusions 13 are provided on each rotary blade 12 by the same number with a predetermined interval. Each protrusion 13 protrudes toward the upstream side on the upstream surface of each rotary blade 12 and is provided in an arc shape along the rotational direction of each rotary blade 12. [Selection] Figure 1

Description

  The present invention relates to an axial flow impeller and a turbine having the axial flow impeller.

  Conventionally, in order to improve the output efficiency of an impeller of a turbine such as wind power generation, optimization of a blade shape, bending of a blade tip, addition of a vane or a vortex generator, and the like have been performed (for example, Patent Document 1). See), and no significant improvement in output efficiency has been realized. Therefore, with the aim of drastically improving output efficiency, a cylindrical diffuser (commonly known as a wind lens) formed so that the opening area increases from the wind inlet to the outlet is installed so as to surround the outer periphery of the impeller. A technique for increasing the output of the impeller by 2 to 3 times has been developed (for example, see Patent Document 2). Further, a radial turbine using a flow of air or water in the radial direction from the center of rotation is known as one that can achieve high-efficiency rotation (see, for example, Patent Document 3).

JP 2002-349418 A International Publication No. 2010/109800 JP 2006-37791 A

  In the windmill using the wind lens described in Patent Document 2, the wind lens itself is fixed and does not directly contribute to the rotation, and the outer diameter of the outlet is 1.4 times the diameter of the impeller. In the wind turbine using this wind lens, it is necessary to increase the size in order to further increase the output efficiency, but the size of the impeller is limited by the size of the wind lens. For this reason, there has been a problem that there is a limit in improving the output efficiency.

  In addition, the radial flow turbine as described in Patent Document 3 rotates at high efficiency because the impulsive force and reaction force with respect to the turbine increase, but it is still necessary to increase the size in order to further increase the output efficiency. However, since the radial flow turbine has a three-dimensional structure, it is limited in size by the installation space. For this reason, there has been a problem that there is a limit in improving the output efficiency.

  The present invention has been made paying attention to such problems, and an object thereof is to provide an axial-flow impeller and a turbine capable of improving output efficiency without increasing the size.

  The inventor of the present invention pays attention to the fact that in the conventional axial flow type impeller, the radial flow component of the fluid flowing in the radial direction from the rotation center along the impeller rotor blades does not contribute to the rotation of the impeller. As a result of trial and error for a technique for effectively utilizing this radial flow component for the rotation of the impeller, the present invention has been achieved.

That is, the axial-flow impeller according to the present invention is disposed around the predetermined central axis at an angular interval, and is provided to be able to rotate around the central axis in response to a fluid flow along the central axis direction. A plurality of rotor blades, and one or a plurality of projecting portions projecting toward the upstream side on the upstream surface of each rotor blade and provided in an arc shape along the rotation direction of each rotor blade , Each projecting portion is characterized in that a cross section along the rotating surface of each rotor blade has an airfoil shape that swells outside the rotation .

  In the axial flow impeller according to the present invention, when a fluid flowing along the central axis direction hits each rotary blade, the flow pushes each rotary blade to rotate each rotary blade. At this time, the fluid hitting each rotor blade becomes a flow having a rotational direction component and a radial flow direction component of each rotor blade along the upstream surface of each rotor blade. It flows in a direction inclined from the central axis toward the outside from the side edge to the rear edge. A part of the inclined flow hits each protrusion from the central axis side, flows along each protrusion, and escapes to the rear edge in the rotation direction of each rotor blade. At this time, since each protrusion is pushed obliquely by the flow, the force of the rotational direction component of each rotor blade is obtained, and the rotation efficiency of each rotor blade can be increased. Thus, the axial flow impeller according to the present invention can increase the rotation efficiency by using the radial flow component along each rotary blade by providing each protrusion, and without increasing the size, the output Efficiency can be improved. Note that the axial flow impeller according to the present invention may be increased in size to further improve the output efficiency.

  In the axial-flow impeller according to the present invention, each projecting portion is provided in an arc shape along the rotation direction of each rotor blade, and thus is not easily subjected to resistance due to the rotation of each rotor blade. Each protrusion is preferably formed from the front side edge to the rear side edge in the rotation direction of each rotary blade over the entire width of each rotary blade. Each protrusion may be formed by attaching an arc-shaped protruding piece to the surface of each rotor blade, or may be formed by raising the surface of each rotor blade in an arc shape. An arcuate groove may be formed. The arcuate raised shape and the cross section of the groove may be, for example, a triangular shape. Each protrusion may be formed by arranging a plurality of protrusions in an arc shape.

  It is preferable that a plurality of protrusions are provided at predetermined intervals on each rotary blade. Each protrusion may be provided on the downstream surface of each rotor blade. In this case, the radial flow component along the downstream surface of each rotor blade can also be used, and the rotational efficiency of each rotor blade can be further increased. In the axial flow impeller according to the present invention, each of the rotor blades may be any propeller or screw as long as it is an axial flow type, and may be a conventional axial flow type impeller.

In the axial-flow impeller according to the present invention, it is preferable that each protrusion is inclined forward with respect to the rotation direction of each rotor blade. In the axial-flow impeller according to the present invention, each protrusion has an airfoil shape in which the cross section along the rotation surface of each rotor blade swells outside the rotation, and therefore flows on the surface of each rotor blade. The fluid generates lift at each protrusion toward the outside of the rotation. At this time, by rotating each protrusion forward, a rotational direction component of each rotor blade can be obtained from the lift force, so that the rotation efficiency of each rotor blade can be further increased. Further, by tilting each protrusion forward, resistance due to rotation of each rotor blade can be made more difficult to receive, and rotation efficiency can be increased.

The turbine according to the present invention includes the axial-flow impeller according to the present invention.
Since the turbine according to the present invention includes the axial flow impeller according to the present invention, the output efficiency can be improved without increasing the size. The turbine according to the present invention may be any turbine as long as it can convert the kinetic energy of the fluid into rotational energy, such as a steam turbine, a gas turbine, a water turbine for power generation, a wind power generator, and the like.

  ADVANTAGE OF THE INVENTION According to this invention, the axial-flow impeller and turbine which can improve output efficiency can be provided, without enlarging.

BRIEF DESCRIPTION OF THE DRAWINGS (a) Front view which shows the axial-flow impeller of embodiment of this invention, (b) The cutting part end view which passes along the center axis | shaft and the center of a rotary blade. It is the front view which expanded the protrusion part which shows the force which acts on a protrusion part of the axial-flow impeller shown in FIG. The front view which shows the head and one rotary blade of the 1st modification of the (a) rotary blade of the axial-flow impeller of embodiment of this invention, (b) It passes along the center axis | shaft and the center of a rotary blade. FIG. 6 is a cut-part end view, (c) a front view showing a head and one rotary blade of a second modification of the rotary blade, and (b) a cut-part end view passing through the central axis and the center of the rotary blade. The front view which shows the head and one rotary blade of the 3rd modification of the (a) rotary blade of the axial-flow impeller of embodiment of this invention, (b) It passes along the center axis | shaft and the center of a rotary blade. It is a cutting part end view.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 4 show an axial-flow impeller according to an embodiment of the present invention.
As shown in FIG. 1, the axial flow impeller 10 includes a head 11, a plurality of rotating blades 12, and a plurality of protrusions 13.

The head 11 has a conical shape and is provided so as to be rotatable about its central axis.
Each rotary blade 12 has an elongated plate shape, and is arranged around the head 11 at equiangular intervals. Each rotary blade 12 extends from the head 11 in the radial direction, and is attached so that one surface faces the front side of the head 11. Each rotor blade 12 is provided so as to be rotatable around the central axis of the head 11 and inclined with respect to the central axis direction of the head 11 when receiving a fluid flow along the central axis direction of the head 11. .

  Each protrusion 13 is plate-shaped, and the same number of protrusions 13 are provided at predetermined intervals on each rotor blade 12. Each protrusion 13 is provided on the upstream surface of each rotor blade 12 so as to protrude toward the upstream side. Each protrusion 13 is provided vertically upright with respect to the surface of each rotor blade 12. Each protrusion 13 is provided in a circular arc shape along the rotational direction of each rotary blade 12 over the entire width of each rotary blade 12 from one side edge to the other side edge of each rotary blade 12. In the specific example shown in FIG. 1, the rotor blades 12 are composed of six sheets, and five protrusions 13 are provided on each rotor blade 12.

Next, the operation will be described.
In the axial flow impeller 10, when a fluid flowing along the central axis direction hits each rotary blade 12, the flow pushes each rotary blade 12 to rotate each rotary blade 12. At this time, the fluid hitting each rotary blade 12 becomes a flow having a rotational direction component and a radial flow direction component of each rotary blade 12 along the upstream surface of each rotary blade 12. From the front side edge in the rotational direction to the rear side edge, it flows in a direction inclined outward from the central axis. In the specific examples shown in FIGS. 1 and 2, each rotor blade 12 rotates in the direction of arrow A, and fluid flows in the direction of arrow B on the surface of each rotor blade 12.

  A part of the inclined flow hits each protrusion 13 from the central axis side, flows along each protrusion 13, and escapes to the rear edge in the rotation direction of each rotor blade 12. At this time, since each protrusion 13 is pushed obliquely by the flow, the force of the rotational direction component of each rotary blade 12 is obtained, and the rotational efficiency of each rotary blade 12 can be increased. In the specific example shown in FIG. 2, when the flow in the direction of the arrow B hits each protrusion 13, an impulse C and a reaction D are generated by the flow, and the rotation of the rotor 12 is generated from the resultant force E. A direction component is obtained, and the rotation efficiency of each rotor blade 12 can be increased.

  As described above, the axial flow impeller 10 can increase the rotation efficiency by using the radial flow components along the rotary blades 12 by providing the protrusions 13, and can increase the output efficiency without increasing the size. Can be improved. Further, even when the axial flow impeller 10 is tilted backward by the downwind method or when coning occurs in which each rotor blade 12 is inclined downstream due to the pressure of the fluid, the radial flow component is increased by each. The protrusion 13 can be used effectively, and the rotation efficiency can be increased. In addition, the axial flow impeller 10 can effectively utilize the radial flow component that increases due to the disk effect by the protrusions 13 even when the rotary blades 12 rotate at a high speed, thereby improving the rotation efficiency. it can.

  Further, the conventional impeller has little contribution to rotation at the end of each rotary blade on the central axis side, but the axial impeller 10 also protrudes from the end of each rotary blade 12 on the central axis side. By providing the part 13, the contribution to the rotation by the part can be increased and the rotation efficiency can be increased. Further, the axial flow impeller 10 is less susceptible to resistance due to the rotation of each rotary blade 12 because each protrusion 13 is provided in an arc shape along the rotation direction of each rotary blade 12. The axial-flow impeller 10 can be used as an impeller of a turbine such as a steam turbine, a gas turbine, a power generation water turbine, or a wind power generator. Thereby, output efficiency can be improved, without enlarging a turbine.

  In the axial flow impeller 10, each protrusion 13 may be provided on the downstream surface of each rotary blade 12. In this case, the radial flow component along the downstream surface of each rotor blade 12 can also be used, and the rotational efficiency of each rotor blade 12 can be further increased. Further, as shown in FIGS. 3A and 3B, the axial flow impeller 10 is provided with alternately a raised portion 21 in which the surface of each rotary blade 12 has an arc shape and an arc-shaped groove 22. A shape may be formed, and each raised portion 21 may form each protruding portion 13. The cross sections of the raised portion 21 and the groove 22 are triangular. Further, as shown in FIGS. 3C and 3D, each protrusion 13 may be formed by arranging a plurality of protrusions 23 in an arc shape.

  Further, as shown in FIG. 4, each protrusion 13 has an airfoil shape in which the cross section along the rotation surface of each rotary blade 12 swells outside the rotation, and with respect to the rotation direction of each rotary blade 12. May be tilted forward. In this case, as shown in FIG. 4A, the fluid flows along the surface of each rotary blade 12 along each airfoil-shaped protrusion 13, so that lift is generated outward of rotation at each protrusion 13. F is generated. At this time, since each rotor blade 12 is tilted forward, the rotational direction component of each rotor blade 12 is obtained from the lift F, and the rotational efficiency of each rotor blade 12 can be further increased. Further, since each rotor blade 12 is tilted forward, it is possible to further reduce resistance to the fluid (arrow B) flowing obliquely on the surface of each rotor blade 12 and to increase the rotation efficiency.

[Rotation experiment]
Using the axial flow impeller 10 shown in FIG. In the axial-flow impeller 10 used in the experiment, the diameter of each rotor blade 12 is 280 mm, the pitch angle is 10 degrees, and the height of each protrusion 13 is 5 mm. Moreover, the wind of the wind speed of 5 m / s was applied from the front of the axial flow impeller 10, and the rotation speed of each rotary blade 12 was measured with the non-contact infrared type tachometer. For comparison, an experiment was also performed on an impeller having the same conditions except that the protruding portion 13 was not provided.

The experimental results are shown in Table 1. In Table 1, each value of the impeller without the projecting portion 13 is set to 1.00, and the result of the axial flow impeller 10 is shown. The output is weight × number of rotations.

  As shown in Table 1, it was confirmed that the axial flow impeller 10 having the protruding portion 13 has an output efficiency improved by 130% or more compared to the conventional impeller without the protruding portion 13.

DESCRIPTION OF SYMBOLS 10 Axial flow impeller 11 Head 12 Rotary blade 13 Protrusion

21 upper part 22 groove 23 protrusion

Claims (4)

A plurality of rotor blades disposed at angular intervals around a predetermined central axis and provided to be able to rotate around the central axis in response to a fluid flow along the central axis direction;
The upstream surface of each rotor blade has one or more protrusions protruding toward the upstream side and provided in an arc shape along the rotation direction of each rotor blade ,
An axial-flow impeller characterized in that each protrusion has an airfoil shape in which a cross section along the rotation surface of each rotor blade swells outside the rotation . 2. The axial-flow impeller according to claim 1 , wherein each protrusion is formed by arranging a plurality of protrusions in an arc shape. The axial flow impeller according to claim 1 or 2 , wherein each protrusion is inclined forward with respect to the rotation direction of each rotor blade. A turbine comprising the axial flow impeller according to any one of claims 1 to 3 .

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