JP2020033885A - Axial flow impeller and turbine - Google Patents

Abstract

To provide an axial flow impeller capable of improving output efficiency without inviting enlargement, and a turbine.SOLUTION: A plurality of rotary blades 13 is arranged at a regular angular interval around a predetermined central axis, extends in a radial direction from the central axis, and is provided so as to be rotatable around the central axis with the flow of fluid along the central axis direction. A plurality of auxiliary blades 14 is provided on the upstream surface and/or downstream surface of each rotary blade 13 with an interval 16 spaced from each rotary blade 13. The gap 16 between each rotary blade 13 and the corresponding auxiliary blade 14 may be wider or narrower on the rear side with respect to the front side in the rotation direction of each rotary blade 13.SELECTED DRAWING: Figure 1

Description

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

  Conventionally, in order to improve the output efficiency of a turbine impeller for wind power generation or the like, optimization of an airfoil, bending of a blade tip, provision of a vane or a vortex generator, and the like have been performed (for example, Patent Document 1). See), no significant improvement in output efficiency has been realized. Therefore, with the aim of greatly improving the output efficiency, a cylindrical diffuser (commonly known as a wind lens) formed so that the opening area expands from the inlet to the outlet of the wind is attached so as to surround the outer periphery of the impeller. A technique for increasing the output of the impeller by a factor of two to three has been developed (for example, see Patent Document 2).

  In a windmill using this wind lens, the wind lens itself is fixed and does not directly contribute to rotation, and the outer diameter of its outlet is 1.4 times the diameter of the impeller. This wind lens is an expansion type annular diffuser for fluid having a large opening area on the outflow side, and has a suction effect of increasing the speed on the inflow side, so that the output efficiency of the impeller can be increased.

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

  However, in the wind turbine using the wind lens described in Patent Document 2, it is necessary to increase the size of the impeller in order to further increase the output efficiency. For example, the outer periphery of a large wind power generation impeller having a diameter exceeding 100 m is used. In addition, it is very difficult to provide a wind lens having an inner diameter exceeding 100 m. As described above, in the windmill described in Patent Document 2, since the size of the wind lens is limited by the size of the impeller, there is a problem that improvement in output efficiency is limited.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide an axial impeller and a turbine capable of improving output efficiency without increasing the size.

  In order to achieve the above object, the axial impeller according to the present invention is disposed at equal angular intervals around a predetermined central axis, extends radially from the central axis, and extends in the central axis direction. A plurality of rotors rotatably provided around the central axis in response to a fluid flow along the rotor, and a gap between each of the rotors on an upstream surface and / or a downstream surface of each rotor. And a plurality of auxiliary wings provided apart from each other.

  In the axial impeller according to the present invention, the gap between each rotor and the corresponding auxiliary blade may be wider or narrower on the rear side than the front side in the rotation direction of each rotor. Good.

  In the axial flow impeller according to the present invention, when a fluid flowing along the central axis direction hits each of the rotors, the flow pushes each of the rotors so that each of the rotors rotates. At this time, since there is a gap between each rotor and each auxiliary wing provided on the upstream surface and / or downstream surface of each rotor, the rotation of each rotor is The surrounding fluid flows in from the front side in the direction and flows toward the rear side. When the gap between the rotor and the auxiliary blade is wider on the rear side than on the front side in the rotation direction of each rotor, the pressure is reduced on the rear side, so that a suction effect in which the front side is accelerated occurs. . In addition, when the gap between the rotor and the auxiliary blade is narrower on the rear side than on the front side in the rotation direction of each rotor, the pressure on the front side is increased, so that the rear side is accelerated. Occurs. The axial impeller according to the present invention is configured such that, in accordance with the density of the surrounding fluid, the speed-up of the fluid due to the suction effect and the speed-up effect acts in a direction to accelerate the rotation of each rotor, The number of rotations of each rotor can be increased.

  For example, when the surrounding fluid is air, since the density is 1/830 of that of water, the pressure reduction on the rear side is small and the suction effect is small. For this reason, the gap between the rotor and the auxiliary wing is made narrower on the rear side than the front side in the rotation direction of each rotor, so that the rotational speed of each rotor is reduced, in expectation of the speed increasing effect rather than the suction effect. Can be increased. On the other hand, when the surrounding fluid is water, the suction effect becomes large, so that the gap between the rotor and the auxiliary blade is made wider on the rear side than on the front side in the rotation direction of each rotor, so that each The number of revolutions of the rotor can be increased. As described above, the axial impeller according to the present invention can increase the rotation efficiency by adjusting the gap between the rotating blade and the auxiliary blade according to the surrounding fluid, thereby increasing the size of each rotating blade. Without this, the output efficiency can be improved.

  In the axial-flow impeller according to the present invention, it is preferable that each rotor has a blade-shaped shape whose cross section perpendicular to the radial direction swells toward the upstream side of the fluid. Further, it is preferable that each of the auxiliary wings has an airfoil shape whose cross section perpendicular to the radial direction swells toward the upstream side of the fluid. In these cases, by making the airfoil shape, lift is generated in each of the rotary wings and each of the auxiliary wings. For this reason, the rotation efficiency of each rotor can be further improved by adjusting the mounting angles of each rotor and each auxiliary blade so that the lift has a component in the rotation direction of each rotor.

  The axial-flow impeller according to the present invention may have a reinforcing portion provided to connect the respective rotary blades and the corresponding auxiliary blades so as to hold the gap. In this case, the rotating blades can be stably rotated with high rotation efficiency by the reinforcing portion.

A turbine according to the present invention includes the axial impeller according to the present invention.
Since the turbine according to the present invention includes the axial 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 the kinetic energy of the fluid can be converted into rotational energy, and examples thereof include a steam turbine, a gas turbine, a water turbine for power generation, and a wind turbine.

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

It is (a) front view and (b) right side view which show the axial-flow impeller of embodiment of this invention. (A)-(k) It is an AA line end figure which shows the modification of a rotating blade and an auxiliary | assistant blade of the axial-flow impeller shown in FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 and 2 show an axial impeller according to an embodiment of the present invention.
As shown in FIG. 1, the axial impeller 10 has a spinner 11, a nacelle 12, a plurality of rotating blades 13, a plurality of auxiliary blades 14, and a plurality of reinforcing portions 15.

  The spinner 11 and the nacelle 12 are arranged such that the spinner 11 is on the leeward side and the nacelle 12 is on the leeward side, and form a spindle shape as a unit. The spinner 11 is provided on the nacelle 12 so as to be rotatable around its central axis. The nacelle 12 houses therein a gearbox and a generator.

  The plurality of rotating blades 13 are formed in an elongated plate shape and are arranged around the spinner 11 at equal angular intervals. Each rotary wing 13 extends from the spinner 11 in the radial direction, and is mounted such that one surface faces the front side of the spinner 11. Each rotary wing 13 is provided to be inclined with respect to a rotating surface so as to be rotatable around the central axis of the spinner 11 when receiving a fluid flow along the central axis direction of the spinner 11.

  The plurality of auxiliary wings 14 have an elongated plate shape, and a gap 16 is provided between each of the rotary blades 13 on the upstream surface and / or the downstream surface of the rotary blade 13 so as to surround the spinner 11. Are located in Each auxiliary wing 14 is provided to extend from the spinner 11 in the radial direction. In the specific example shown in FIG. 1, the rotating blade 13 and the auxiliary wing 14 each include three pieces. In addition, each auxiliary wing 14 is arranged so as to cover the entire surface on the downstream side of each rotor 13, but may be arranged on the downstream side, or only on the front side in the rotation direction or on the rear side. It may be arranged to cover only

  It is preferable that each of the rotor blades 13 and each of the auxiliary blades 14 have an airfoil shape in which a cross section perpendicular to the extending direction swells on the upstream side of each of the rotor blades 13. Good. As shown in FIG. 2, in the axial impeller 10, the gap 16 between each rotor 13 and the corresponding auxiliary blade 14 is wider on the rear side than on the front side in the rotation direction of each rotor 13. Or may be narrow. For example, each of the plate-like auxiliary wings 14 is located upstream of each of the rotating blades 13 such that each of the rotating blades 13 has an airfoil shape, and the gap 16 is wider on the rear side than on the rotating side of each of the rotating blades 13. The front surface in the rotation direction (see FIGS. 2A and 2D), the rear surface (see FIGS. 2B and 2E), or the entire surface (see FIGS. 2C and 2F). ) And (g)). In addition, the plate-shaped auxiliary wings 14 are arranged on the downstream surface of each of the rotating blades 13 in the front of the rotating direction so that the gap 16 is narrower on the rear side than on the rotating side of each of the rotating blades 13 (see FIG. 2 (d)), the rear side (see FIG. 2 (e)), or the whole (see FIGS. 2 (f) and 2 (g)). Further, each auxiliary wing 14 may have a curved airfoil shape (see FIGS. 2H and 2I) or may have an uncurved airfoil shape (FIG. 2). (J), (k)).

  The plurality of reinforcing portions 15 are formed in a plate shape, and connect the rotating blades 13 and the auxiliary wings 14 so as to maintain a gap 16 between each rotating blade 13 and the corresponding auxiliary wing 14. Is provided. Each reinforcing portion 15 is attached so as to extend in the rotation direction of each rotor 13.

  In the specific example shown in FIG. 1, five reinforcing portions 15 are provided at equal intervals for one rotating blade 13. Further, the axial impeller 10 is attached to the upper end of the column 17 so as to rotatably fix the nacelle 12 about a vertical axis.

Next, the operation will be described.
When the fluid flowing along the central axis direction of the spinner 11 hits each of the rotating blades 13, the axial-flow impeller 10 pushes each of the rotating blades 13, and in addition, the blade-shaped cross-sectional shape of each of the rotating blades 13. Each rotary wing 13 is rotated by a lift caused by a pressure difference between the upstream side and the downstream side in the above. At this time, since there is a gap 16 between each rotary wing 13 and each auxiliary wing 14 provided on the upstream surface and / or the downstream surface of each rotary wing 13, The surrounding fluid flows in from the front side in the rotation direction of each rotary wing 13 and flows toward the rear side. When the gap 16 between the rotor 13 and the auxiliary blade 14 is wider on the rear side than on the front side in the rotation direction of each rotor 13, the pressure is reduced on the rear side, so that the suction speed is increased on the front side. The effect occurs. When the gap 16 between the rotor 13 and the auxiliary blade 14 is narrower on the rear side than on the front side in the rotation direction of each rotor 13, the pressure on the front side is increased, and the speed on the rear side is increased. A speed increasing effect occurs. The axial flow impeller 10 is configured such that, according to the density of the surrounding fluid, the speed of the fluid due to the suction effect and the speed-up effect acts in the direction in which the rotation of each rotary blade 13 is accelerated, so that each rotation is performed. The rotation speed of the wing 13 can be increased.

  For example, when the surrounding fluid is air, since the density is 1/830 of that of water, the pressure reduction on the rear side is small and the suction effect is small. For this reason, in order to expect a speed-up effect rather than a suction effect, the gap 16 between the rotor 13 and the auxiliary blade 14 is made narrower on the rear side than on the front side in the rotation direction of each rotor 13, so that each rotor 13 can be increased. On the other hand, when the surrounding fluid is water, the suction effect is increased, so that the gap 16 between the rotating blades 13 and the auxiliary blades 14 is made wider on the rear side than on the rotating direction of each rotating blade 13. Thereby, the rotation speed of each rotary wing 13 can be increased. As described above, the axial flow impeller 10 can increase the rotation efficiency by adjusting the interval of the gap 16 between the rotating blade 13 and the auxiliary blade 14 according to the surrounding fluid, and can increase the size of each rotating blade 13. Without increasing the output efficiency.

  The axial flow impeller 10 generates lift in each of the rotating blades 13 and each of the auxiliary blades 14 by forming each of the rotating blades 13 and each of the auxiliary blades 14 into an airfoil shape. For this reason, the rotation efficiency of each rotor 13 can be further improved by adjusting the mounting angle of each rotor 13 and each auxiliary blade 14 so that the lift has a component in the rotation direction of each rotor 13. . Moreover, since the axial-flow impeller 10 is provided with the reinforcing portion 15, the rotating blades 13 can be stably rotated with high rotation efficiency.

  The axial-flow impeller 10 can be used as an impeller of a turbine such as a steam turbine, a gas turbine, a water turbine for power generation, and a wind turbine. Thereby, the output efficiency can be improved without increasing the size of the turbine.

[Rotation experiment]
Using the 3D printer, the axial impeller 10 was manufactured, and a rotation experiment was performed. As the axial impeller 10, each of the rotary blades 13 and each of the auxiliary blades 14 were manufactured in four shapes shown in FIGS. 2 (c), (h), (j), and (k). The manufactured axial impeller 10 has a diameter of 300 mm, the diameter of the spinner 11 is 90 mm, and has three rotating blades 13. Each rotor 13 had a length of 105 mm, a width of 30 mm, an airfoil shape of NACA 4309, an angle of attack with respect to the rotating surface of 14 degrees, and no twist from the root to the tip. Each aileron 14 has a length of 105 mm, a width of 15 mm and an airfoil type of NACA 4309.

  In the axial-flow impeller 10 of FIGS. 2C and 2H, the gap 16 between each rotor 13 and each auxiliary blade 14 is wider on the rear side than on the front side in the rotation direction of each rotor 13. 2 (j) and 2 (k), the gap 16 between each rotor 13 and each auxiliary blade 14 is narrower on the rear side than on the front side in the rotation direction of each rotor 13 in the axial flow impeller 10 of FIGS. I have. In addition, the axial-flow impeller 10 for comparison is composed of only the respective rotating blades 13 and not having the respective auxiliary blades 14 (hereinafter referred to as “general rotating blades”). An 18-degree angle (hereinafter referred to as an "18-degree rotor") was produced.

  In the experiment, a three-phase motor for drone (measured value of internal resistance 0.2 Ω / phase) was diverted as a generator for output confirmation. In addition, in order to eliminate the influence of the weight difference between the axial impellers 10, a wide aluminum thin tape is attached to the surface of each of the rotary blades 13, and the length and number of the assembly screws are adjusted. The weight of the flow impeller 10 is unified to 86.5 g.

  In the experiment, a blower with a blade diameter of 30 cm was used, the distance from the blower outlet to each axial flow impeller 10 was set to 5 cm, air was blown at a wind speed of 5 m / s, and no load or heavy load (all-phase short circuit) ), Each axial flow impeller 10 was rotated, the rotation speed and phase voltage were measured, and the three-phase output power (W) and efficiency were calculated. Further, experiments were performed when the gap 16 between each rotor 13 and each auxiliary blade 14 was opened and when the gap 16 was closed on the inflow side. Table 1 shows the experimental results.

  As shown in Table 1, the axial impeller 10 in FIGS. 2C and 2H has a slightly increased rotation speed under heavy load at the inlet opening compared to the general rotary blade, and Performance improvement due to the effect is observed. In addition, the axial flow impeller 10 of FIGS. 2 (j) and 2 (k) has a heavy load output multiple of twice or more at the inlet opening compared to a general rotor, and is remarkable due to the speed increasing effect. Performance improvement is observed. Further, the rotating speed under heavy load is higher for the 18-degree rotating blades than for the general rotating blades. However, the axial flow impeller 10 of FIG. It was confirmed that the rotation speed was large and the performance improvement due to the speed increasing effect was particularly remarkable. For this reason, the axial impeller 10 of FIGS. 2 (j) and 2 (k) can obtain more output at a low rotation speed, and can be used for a large-scale commercial wind turbine or the like which does not necessarily need to rotate at high speed. Deemed suitable.

  Further, since the effect of improving the performance of the axial impeller 10 of FIGS. 2 (j) and 2 (k) in air is more remarkable than that of the axial impeller 10 of FIGS. 2 (c) and 2 (h), In order to obtain more output, the gap 16 between the rotor 13 and the auxiliary blade 14 is made narrower on the rear side than on the front side in the rotation direction of each rotor 13 in expectation of the speed increasing effect in the air. It would be better to use In addition, since a suction effect can be expected underwater, it is considered that a gap 16 between the rotating blades 13 and the auxiliary blades 14 that is wider on the rear side than on the rotating direction of each rotating blade 13 can be used.

  Further, in the axial-flow impeller 10 of FIGS. 2C and 2H, the rotation speed at the time of heavy load in a state where the inlet is closed is slightly higher than that in a state where the inlet is open. On the other hand, it was confirmed that the axial flow impeller 10 of FIGS. From this, it is considered that the axial-flow impeller 10 in FIGS. 2 (j) and 2 (k) exhibits the diffuser effect due to the opening.

DESCRIPTION OF SYMBOLS 10 Axial impeller 11 Spinner 12 Nacelle 13 Rotary wing 14 Auxiliary wing 15 Reinforcement part 16 Crevice 17 Prop

Claims (7)

Arranged equidistantly from each other around a predetermined central axis, extending radially from the central axis, receiving a flow of fluid along the central axis direction, and rotatably provided around the central axis. Multiple rotors,
On the upstream surface and / or downstream surface of each rotor, a plurality of auxiliary wings provided with a gap between each rotor,
An axial impeller comprising:   2. The axial-flow impeller according to claim 1, wherein a gap between each of the rotor blades and the corresponding auxiliary blade is wider on a rear side than on a front side in a rotation direction of each rotor blade.   2. The axial-flow impeller according to claim 1, wherein a gap between each of the rotors and the corresponding auxiliary blade is narrower on a rear side than on a front side in a rotation direction of each rotor.   4. The axial flow according to claim 1, wherein each rotor has a cross section perpendicular to the radial direction having an airfoil shape bulging upstream of the fluid. 5. Impeller.   The axial flow impeller according to claim 4, wherein each of the auxiliary wings has a cross section perpendicular to the radial direction having an airfoil shape bulging upstream of the fluid.   The axial flow blade according to any one of claims 1 to 5, further comprising a reinforcing portion provided so as to connect the rotary blades and the corresponding auxiliary blades so as to hold the gap. car. A turbine comprising the axial impeller according to any one of claims 1 to 6.

Images