Wind power generator

Details Wind power generator Wind power generator

2003-02-03

2004-06-29

Waks, Joseph (Department: 2834)

Prime-mover dynamo plants

Fluid-current motors

Wind

C415S208100

Reexamination Certificate

active

06756696

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to a wind power generator that produces high output power of electricity by increasing wind flow speed.
Recently, in the field of power generation, wind power generators are attracting attention from such aspects as the breakaway from oil-based energy production and conservation of clean environment. Wind power generators, which utilize a natural wind flow, sometimes fail to produce sufficient wind power depending on geographical and weather conditions where generators are installed. Therefore, it has been suggested that by employing some means to generate sufficient power a weak wind flow is accelerated.
The present inventors have provided a wind speed-up device capable of efficiently increasing wind flow speed with a simple structure, which is disclosed in Unexamined Japanese Patent Publication No. 2002-213343.
FIG. 8
is a longitudinal sectional view showing the wind speed-up device in Unexamined Japanese Patent Publication No. 2002-213343.
The wind speed-up device illustrated in
FIG. 8
comprises a wind tunnel body
51
having a long cylindrical shape and expanding from an inlet
52
toward an outlet
53
through which wind flows. On an opening edge of the inlet
52
of the wind tunnel body
51
provided is an inlet shroud
55
opened outwardly with a curved surface. An opening edge of the outlet
53
is provided with a collar-shaped flange
56
that outwardly expands. An area adjacent to the inlet
52
is adopted for a position for outputting the generated wind power.
By the above structure, wind around a central axis of the wind tunnel body
51
, flowing in from the front of the inlet
52
, pulls in slow wind flowing along an inner wall surface of the wind tunnel body
51
and, on the rear side of the outlet
53
, the wind around the central axis and wind flowing outside the wind tunnel body
51
pull in the slow wind flowing on the inner wall surface of the wind tunnel body
51
, thereby obtaining a high-speed wind area adjacent to the inlet
52
inside the wind tunnel body
51
to output wind power.
By employing the above-described wind speed-up device to construct a wind power generator with a wind turbine for generating electricity disposed at a position for outputting wind power adjacent to the inlet
52
, the wind turbine disposed at the position adjacent to the inlet
52
inside the wind tunnel body
51
, which is a high-speed wind area in the wind tunnel body
51
of the wind speed-up device, can be efficiently rotated even by weak wind outside, which leads to a significant improvement in power generating ability as a wind power generator.
In the wind speed-up device of Unexamined Japanese Patent Publication No. 2002-213343, it is further suggested that the angle of inclination of a side wall portion against the axis of the wind tunnel body
51
be preferably in a range from 2 to 5 degrees. With the angle of inclination below 2 degrees, even when the ratio of the length of the wind tunnel body
51
to the diameter of the inlet
52
of the wind tunnel body
51
is increased, the effect of increasing the speed-up ratio tends to become smaller. With the angle of inclination above 5 degrees, the effect of pulling in the slow wind flowing on the inner wall surface of the wind tunnel body tends to become smaller. Accordingly, with a range from 2 to 5 degrees, the slow wind flowing on the inner wall surface of the wind tunnel body can be efficiently pulled in.
However, although the above-described wind speed-up device, when used as itself, has the greatest speed-up effect with a range from 2 to 5 degrees, the device provided with a wind turbine disposed for generating electricity adjacent to the inlet
52
of the wind tunnel body
51
has proven not to be most appropriate with the angle of inclination in a range from 2 to 5 degrees. This is because the wind turbine rotating within the wind tunnel body
51
has an influence on a wind flow passing through the wind tunnel body
51
.
An object of the present invention is to provide a wind power generator having a wind turbine rotating inside a wind tunnel body, which can generate high output power by efficiently increasing wind flow speed.
SUMMARY OF THE INVENTION
A wind power generator according to the present invention is a wind power generator comprising a cylindrical wind tunnel body expanding toward a flowing direction of wind and a wind turbine for generating electricity disposed at a position adjacent to an inlet for a wind flow of the wind tunnel body, wherein an angle of inclination of a side wall portion of the wind tunnel body against an axis of the wind tunnel body is in a range from 5 to 25 degrees or, preferably, from 5 to 14 degrees.
FIGS. 1 and 2
show distribution of static pressure and wind velocity at positions from the front through the inside to the rear of the wind tunnel body. The horizontal axes in
FIGS. 1 and 2
indicate a ratio obtained by normalizing a horizontal position X of which origin is the inlet of the wind tunnel body by length L of the wind tunnel body, where the direction of the outlet of the wind tunnel body is indicated as positive. The distribution of static pressure in
FIG. 1
indicates the difference from the static pressure in a position free from influence of the wind tunnel body, and the vertical axis shows a ratio obtained by normalizing the difference in static pressure by dynamic pressure of approach wind velocity U∞. The vertical axis of
FIG. 2
shows a ratio obtained by normalizing wind velocity U by the approach wind velocity U∞.
As shown in
FIG. 1
, with respect to the wind tunnel body disposed at an open space, the static pressure of wind both in front of the inlet and at the rear of the outlet is substantially equal to the static pressure of atmospheric pressure outside the wind tunnel body. In the case of the cylindrical wind tunnel body expanding toward a flowing direction of wind, as the static pressure inside the wind tunnel body increases in a direction toward the outlet as shown in
FIG. 1
, the pressure greatly drops around the inlet inside the wind tunnel body. Accordingly, wind flowing in from the front of the inlet into the wind tunnel body sharply accelerates around the inlet as shown in FIG.
2
and gradually decelerates toward the outlet while the pressure is recovered to become substantially equal to the static pressure of the atmospheric pressure at the outlet as shown in FIG.
1
.
In other words, in the cylindrical wind tunnel body expanding toward a flowing direction of wind, wind has negative pressure and converges around a position on a slightly downstream side of the inlet inside the wind tunnel body, which provides an area of high-speed wind to output wind power thereat.
In a wind power generator of the present invention, a wind turbine for generating power is disposed at a position adjacent to the inlet of the wind tunnel body. Thus, resistance by the wind turbine itself can prevent separation of a wind flow on an inner wall surface of the wind tunnel body even if an angle of inclination of a side wall portion against an axis of the wind tunnel body is increased to more than 5 degrees. Furthermore, since rotation of the wind turbine accelerates flow rate of wind in a radial direction of the wind tunnel body, the wind flow on the inner wall surface of the wind tunnel body is further prevented from separating, and wind flowing in from the inlet of the wind tunnel body can smoothly flow along the inner wall surface of the wind tunnel body to the outlet. Therefore, even if the angle of inclination of the side wall portion is increased up to 25 degrees at the maximum, separation of the wind flow on the inner wall surface of the wind tunnel body can be prevented until the wind flow reaches the outlet.
When the angle of inclination of the side wall portion exceeds 14 degrees, separation of wind on the inner wall surface of the wind tunnel body shows a slight tendency to occur. However, with high-speed rotation of the wind turbine for generating electricity, the wind flow can be re

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