JP2006152854A - Wind mill with diffuser - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the power-generation efficiency of a wind mill with a diffuser by sucking air in a boundary layer near a diffuser outlet to heighten an in-flow wind speed of a diffuser inlet. <P>SOLUTION: The small-area opening 21 and large area opening 22 of a diffuser 20 are arranged at windward and leeward sides, respectively, and a rotor 30 and a nacelle 40 are arranged at the windward side of a flow path space surrounded by the diffuser 20. The diffuser 20 and the nacelle 40 are interconnected with a coupling part 50, and the holes 23 are provided on an inner wall 22a near the large area opening 22 of the diffuser 20. Further, a flow path communicating from the holes 23 to the inside of the nacelle 40 through the insides of diffuser 20 and coupling part 50 is set up, and an exhaust outlet is provided on the nacelle 40 to generate an air stream from the communicating flow path toward the exhaust outlet by an air stream-generating means (a cooling fan 70). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wind turbine with a diffuser.

  Currently, as a means for increasing the amount of power generated by a horizontal axis wind turbine, a diffuser (expansion tube) formed so that the flow passage area gradually increases is employed. The diffuser inlet (small area opening) is arranged on the leeward side, the outlet (large area opening) is arranged on the leeward side, and the rotor of the horizontal axis wind turbine is arranged near the diffuser inlet to flow into the rotor. The amount of power generation can be increased by increasing the wind speed.

In recent years, various techniques have been proposed for further improving the wind collecting effect by reducing the pressure in the vicinity of the outlet of the diffuser. For example, an attempt has been made to increase the inflow air velocity at the diffuser inlet by attaching a “collar” to the diffuser outlet to generate a Karman vortex and generating a low pressure region near the diffuser outlet (for example, Non-Patent Document 1). reference.).
Yuji Oya and five others, “High output of wind power generation by wind lens (local concentration effect of wind)”, Proceedings of the 33rd Fluid Dynamics Conference, Japan Aerospace Society, 2001, p.229-232

  However, since the technique described in Non-Patent Document 1 actively generates Karman vortices near the diffuser outlet, the boundary layer peels off near the outlet 120 of the diffuser 100 as shown in FIG. As a result, the flow path does not substantially expand. For this reason, the inflow wind speed to the inlet 110 of the diffuser 100 may become low, and there exists a possibility that electric power generation efficiency may fall.

  An object of the present invention is to improve power generation efficiency by increasing the inflow air velocity at the diffuser inlet by suppressing separation of the boundary layer in the vicinity of the diffuser outlet in the wind turbine with a diffuser.

  In order to solve the above-mentioned problems, the invention according to claim 1 is a diffuser in which the flow path area is gradually increased and the small area opening is disposed on the windward side and the large area opening is disposed on the leeward side. A rotor that rotates around a rotating shaft that is disposed in the vicinity of the small-area opening of the channel space surrounded by the diffuser and extends in the horizontal direction, and a nacelle that supports the rotating shaft. In the wind turbine, a connecting portion that connects the diffuser and the nacelle, a hole provided in an inner wall near the large-area opening of the diffuser, and the nacelle from the hole through the diffuser and the connecting portion A communication flow path leading to the interior of the battery, an exhaust port provided in the nacelle, and an air flow generation means for generating an air flow from the communication flow path to the exhaust port. To.

  According to the first aspect of the present invention, a hole is provided in the inner wall near the exit of the diffuser (a large area opening on the leeward side), and a communication channel extending from the hole to the inside of the nacelle is provided. The airflow generating means generates an airflow that goes from the exhaust to the exhaust port provided in the nacelle. For this reason, the air in the vicinity of the outlet of the diffuser can be guided to the inside of the nacelle via the communication channel and discharged from the exhaust port. Accordingly, separation of the boundary layer on the inner wall of the diffuser outlet can be suppressed, so that the flow path near the diffuser outlet can be substantially expanded. As a result, the inflow wind speed at the diffuser inlet can be increased, and the power generation efficiency can be improved.

  According to a second aspect of the present invention, in the wind turbine with a diffuser according to the first aspect, a generator for converting the rotational force of the rotor into electric power, and heat released from the generator from the exhaust port to the nacelle. A generator cooling fan that discharges to the outside, and the generator cooling fan functions as the airflow generating means.

  According to the second aspect of the present invention, the generator cooling fan that cools the generator by discharging the heat released from the generator from the exhaust port to the outside of the nacelle is caused to function as the airflow generating means. That is, since the function and effect of the present invention (wind collecting function and power generation amount increasing effect) can be obtained by effectively using a cooling fan for a generator that has been used conventionally without separately providing an airflow generating means, Costing can be achieved.

  According to a third aspect of the present invention, in the wind turbine with a diffuser according to the first or second aspect, a generator that converts the rotational force of the rotor into electric power, and the rotational speed of the rotor is increased and transmitted to the generator. And a speed increasing gear cooling fan that discharges heat released from the speed increasing gear to the outside of the nacelle from the exhaust port, and the speed increasing speed cooling fan is configured to generate the airflow. It functions as a means.

  According to the third aspect of the present invention, the speed-up gear cooling fan that cools the speed-up gear by discharging the heat released from the speed-up gear to the outside of the nacelle from the exhaust port is caused to function as the airflow generation means. In other words, the effect of the present invention (wind collecting action and power generation increase effect) can be obtained by effectively using the cooling fan for the speed increaser that has been conventionally used without separately providing an airflow generating means. Cost reduction can be achieved.

  According to the present invention, by providing a hole in the inner wall near the outlet of the diffuser, providing a communication channel from the hole to the inside of the nacelle, and generating an air flow from the communication channel to the exhaust port, The air in the vicinity of the outlet can be led into the nacelle and discharged from the exhaust port. As a result, separation of the boundary layer at the outlet inner wall of the diffuser can be suppressed to achieve smooth airflow in the diffuser, and the inflow air velocity at the diffuser inlet can be increased to improve power generation efficiency.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  First, the structure of the wind turbine 1 with a diffuser which concerns on embodiment of this invention is demonstrated using FIG.1 and FIG.2. As shown in FIGS. 1 and 2, the wind turbine 1 with a diffuser according to the present embodiment includes a tower 10 installed at a predetermined location, a diffuser 20 attached to the top of the tower 10, and a flow path surrounded by the diffuser 20. The rotor 30 and the nacelle 40 disposed in the space, the connecting portion 50 connecting the diffuser 20 and the nacelle 40, the generator 60 mounted in the nacelle 40, the cooling fan 70, and the like are configured.

  As shown in FIGS. 1 and 2, the diffuser 20 is an expansion pipe formed so that the flow path area gradually increases, and is disposed on the leeward side with a small area opening 21 disposed on the leeward side. A large area opening 22. As shown in FIG. 2, a plurality of orifices (holes) 23 are provided on the inner wall 22 a in the vicinity of the large-area opening 22 of the diffuser 20. Further, as shown in FIG. 2, a diffuser internal flow path 24 that communicates with each orifice 23 and is connected to a connection internal flow path 51 described later is provided inside the diffuser 20.

  As shown in FIGS. 1 and 2, the rotor 30 includes two blades 31 that convert wind force into rotational force and a hub 32, and a rotation shaft 33 that is fixed to the hub 32 and extends in the horizontal direction. It is comprised so that it may rotate around. The rotor 30 is disposed on the windward side of the flow path space surrounded by the diffuser 20 (that is, in the vicinity of the small area opening 21).

  As shown in FIGS. 1 and 2, the nacelle 40 is connected to the diffuser 20 by the connecting portion 50 in a state of being disposed on the leeward side of the rotor 30. Various devices such as a generator 60, a cooling fan 70, and a controller (not shown) are mounted inside the nacelle 40. A rotating shaft 33 of the rotor 30 is rotatably attached to the windward end portion of the nacelle 40, and the leeward side end portion of the nacelle 40 is illustrated for discharging the air in the nacelle 40 to the outside. There is no exhaust vent. Further, on the upper and lower surfaces of the nacelle 40, there are provided through holes (not shown) that are aligned with a flow path 51 in the connecting portion described later.

  As shown in FIGS. 1 and 2, the connecting portion 50 that connects the diffuser 20 and the nacelle 40 keeps the attitude of the nacelle 40 constant in the flow path space surrounded by the diffuser 20. In the present embodiment, two plate-like members having a predetermined thickness and disposed above and below the nacelle 40 are employed as the connecting portion 50. As shown in FIG. 2, the inside of the connecting portion 50 is connected to the diffuser passage 24 provided in the diffuser 20 and is aligned with the through hole provided in the nacelle 40. Is provided. The communication channel from the orifice 23 of the diffuser 20 to the inside of the nacelle 40 is configured by the in-diffuser channel 24, the connection-portion channel 51, and the through hole provided in the nacelle 40.

  The generator 60 is mounted inside the nacelle 40 as shown in FIG. 2A, and converts the rotational force of the rotor 30 into electric power. The cooling fan 70 generates an air flow from the windward side to the leeward side in the nacelle 40, thereby discharging heat released from the generator 60 to the outside of the nacelle 40 from the exhaust port to cool the generator 60. To do. Moreover, the cooling fan 70 sucks the boundary layer from the orifice 23 through the communication flow path by generating the air flow from the windward side to the leeward side as described above, and the air flowing into the nacelle 40 is exhausted from the exhaust port. To discharge from. That is, the cooling fan 70 functions as an airflow generating means in the present invention.

  Next, with reference to FIG. 3 and Table 1, a wind collecting action and a power generation amount increasing effect when the wind turbine 1 with a diffuser according to the present embodiment is employed will be described.

First, as shown in FIG. 3, the flow area at the inlet (small area opening 21) of the diffuser 20, the velocity of the airflow, and the static pressure are respectively S ₁ , U ₁ , and p _1, and the outlet (large area) of the diffuser 20 The opening area at the opening 22), the velocity of the air flow and the static pressure are U ₂ , S ₂ and p ₂ , respectively. Then, assuming that the velocity and static pressure of the uniform flow in the flow tube having a cross-sectional area S ₀ are U ₀ and p ₀ and the air density is ρ, Bernoulli's equation (A) and flow equation (B) are as follows: become.

Using the Bernoulli equation (A) and the flow rate equation (B), the velocity of the airflow flowing into the rotor 30 (the velocity of the airflow at the diffuser inlet: hereinafter referred to as “inflowing wind velocity”) U ₁ is obtained. ₁ is expressed as a function of the pressure coefficient C _P2 in the diffuser outlet as shown in equation (C). Such formula (C), the pressure at the diffuser outlet is more incoming wind speed U ₁ is found to increase low (wind collecting action).

Next, when the output coefficient of the diffuser with the wind turbine 1 and eta (constant), an air energy (hereinafter referred to as "Output") E _R per unit can be used for power generation time is expressed by the following formula (D). Then, the equation (E) is obtained by substituting the equation (C) into U ₁ of the equation (D). As shown in equation (E), the output E _R is the be expressed as a function of the pressure coefficient C _P2 in the diffuser outlet.

When this equation (E) is differentiated by the pressure coefficient _CP2 , the following equation (F) is obtained.

Here, focusing on the fact that the pressure p ₂ at the diffuser outlet is sufficiently close to the uniform flow pressure p ₀ , it can be approximated as “C _P2 ≈0” in the equation (F). The approximate expression (G) is obtained by setting “dE _R ” as the output fluctuation “ΔE _R ” and “dC _P2 ” as the pressure coefficient fluctuation “ΔC _P2 ” in the expression (F). Such formula (G), when the pressure at the diffuser outlet is decreased (when the pressure coefficient variation [Delta] C _P2 in the diffuser outlet is negative), the variation amount Delta] E _R of the output E _R increases (output E _R and a positive It becomes clear (power generation increase effect).

<Specific example>
The uniform flow velocity U ₀ is “8 m / s”, the output coefficient η is “0.35”, the air density ρ is “1.225 kg / m ³ ”, the area of the rotor 30 (= flow path area at the inlet of the diffuser) S ₁ is “200 m ² ”, and the flow path area S ₂ at the diffuser outlet is “230 m ² ”. Then, the pressure coefficient C _P2 at the diffuser outlet when the present invention is not applied is “−0.4”, and the pressure coefficient C _P2 at the diffuser outlet when the present invention is applied is “−0.6”. and it obtains the theoretical value of the incoming wind speed U _1, and the output E _R by using equation (E), and the results are shown in Table 1.

As shown in Table 1, when the pressure was decreased coefficient _{C P2} of the diffuser outlet to "-0.6" from "-0.4" is the theoretical value of the incoming wind speed _{U 1} is "0.8 m / s "increases, the theoretical value of the output E _R has become possible to increase" 12.3kW ".

  In the wind turbine 1 with a diffuser according to the embodiment described above, an orifice 23 is provided on the inner wall 22a in the vicinity of the outlet (large-area opening 22) of the diffuser 20, and a communication channel (diffuser) from the orifice 23 to the inside of the nacelle 40 is provided. An internal flow path 24, a connecting section flow path 51 and a through hole), and a cooling fan 70 generates an air flow from the communication flow path to the exhaust port. For this reason, the air in the vicinity of the outlet of the diffuser 20 can be guided to the inside of the nacelle 40 via the communication channel and discharged from the exhaust port. Accordingly, separation of the boundary layer at the outlet inner wall 22a of the diffuser 20 can be suppressed, so that the flow path can be substantially expanded near the outlet of the diffuser 20. As a result, the inflow wind speed at the inlet of the diffuser 20 can be increased, and the power generation efficiency can be improved.

  Moreover, in the windmill 1 with a diffuser which concerns on embodiment described above, the cooling fan 70 which discharges | emits the heat discharge | released from the generator 60 to the exterior of the nacelle 40 from an exhaust port, and cools the generator 60 is an airflow production | generation means. Can function as. That is, it is possible to effectively use the cooling fan 70 for the generator 60 that has been conventionally used without separately providing an airflow generating means, thereby obtaining the effects (wind collecting action and power generation increase effect) of the present invention. Therefore, cost reduction can be achieved.

  In each of the above embodiments, an example in which only the cooling fan 70 for the generator 60 is provided has been described. However, a speed increaser is provided between the rotor 30 and the generator 60, and the speed increaser is cooled. The speed-up gear cooling fan is provided, and the air-flow going from the windward side to the leeward side can be generated by the speed-up gear cooling fan. The speed-up gear cooling fan in such a case functions as the airflow generating means in the present invention. In addition, a dedicated fan other than the generator cooling fan and the speed increasing gear cooling fan can be mounted inside the nacelle 40 as an air flow generating means to generate an air flow from the leeward side toward the leeward side.

  Moreover, in the above embodiment, although the example which has arrange | positioned the connection part 50 (plate-shaped member) on the upper and lower sides of the nacelle 40 was shown, the position of the connection part 50 is not restricted to this, For example, the nacelle 40 The connection part 50 can also be arrange | positioned at right and left. In the above embodiment, a “plate member” is used as the connecting portion 50. However, the connecting portion 50 is a member that can fix the nacelle 40 to the diffuser 20 and can provide a flow path therein. Any material can be used.

  Moreover, in the above embodiment, although the example which provided the some orifice 23 in the inner wall 22a of the large area opening part 22 vicinity of the diffuser 20 was shown, the form of the hole provided in the inner wall 22a of the diffuser 20 is shown to this It is not limited. For example, a slot may be provided instead of the orifice 23, and the slot may be communicated with the in-diffuser flow path 24.

1 is a schematic perspective view of a wind turbine with a diffuser according to an embodiment of the present invention. (A) is sectional drawing of the II-II part of the windmill with a diffuser shown in FIG. 1, (b) is a part of inner wall near the diffuser exit of the windmill with a diffuser shown in (a) from arrow B direction. It is an enlarged view when seen. It is a conceptual diagram showing the airflow in the diffuser of the windmill with a diffuser which concerns on embodiment of this invention. It is a conceptual diagram showing the airflow in the diffuser of the conventional windmill with a diffuser.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Windmill with a diffuser 20 Diffuser 21 Small area opening part 22 Large area opening part 22a Inner wall 23 Orifice (hole)
24 Channel in diffuser (part of communication channel)
30 Rotor 33 Rotating shaft 40 Nacelle 50 Connection part 51 Flow path in connection part (part of communication flow path)
60 generator 70 cooling fan (cooling fan for generator, airflow generating means)

Claims (3)

A diffuser formed so that the flow channel area gradually increases, with a small area opening on the leeward side and a large area opening on the leeward side, and in the vicinity of the small area opening in the flow channel space surrounded by the diffuser In a wind turbine with a diffuser, comprising: a rotor that rotates around a rotating shaft that is disposed in a horizontal direction and a nacelle that supports the rotating shaft;
A connecting portion for connecting the diffuser and the nacelle;
A hole provided in an inner wall near the large-area opening of the diffuser;
A communication flow path from the hole to the inside of the nacelle through the diffuser and the connecting portion;
An exhaust port provided in the nacelle;
An air flow generating means for generating an air flow from the communication channel toward the exhaust port;
A wind turbine with a diffuser characterized by comprising: A generator for converting the rotational force of the rotor into electric power;
A generator cooling fan that discharges heat released from the generator to the outside of the nacelle from the exhaust port, and
The generator cooling fan is:
The wind turbine with a diffuser according to claim 1, wherein the wind turbine functions as the air flow generation means. A generator for converting the rotational force of the rotor into electric power;
A speed increaser that increases the number of rotations of the rotor and transmits it to the generator;
A speed-up gear cooling fan that discharges heat released from the speed-up gear to the outside of the nacelle from the exhaust port, and
The cooling fan for the gearbox is
The wind turbine with a diffuser according to claim 1 or 2, wherein the wind turbine functions as the air flow generation means.

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