JPH05288875A - Magnetic field generating device for magnetohydrodynamic power generation - Google Patents

Abstract

PURPOSE:To obtain a magnetic field generating device for magnetohydrodynamic power generation with a high generation efficiency by making uniform magnetic flux density distribution of a conductive fluid within a channel. CONSTITUTION:The title device allows at least a pair of permanent magnets 5 and 7 to be provided on the inner-periphery surface of a yoke which is formed so that two sets of parallel sides exist on a cross section so that different poles oppose each other while sandwiching the channel of a conductive fluid. Then, a first permanent magnet 5 generating a main magnetic field is provided through a spacing each while sandwiching a plane including a center axis of a channel 4 of the conductive fluid. A second permanent magnet 7 generating a sub magnetic field is provided on the inner-periphery surface of a yoke 20 which crosses the yoke 1 where the first permanent magnet 5 is provided through a spacing each while sandwiching a plane crossing the plane and at the same time a magnetic pole at the side of the channel 4 of the second permanent magnet 7 is formed at the same pole as the magnetic pole of the first permanent magnet 5. Also, division plates 6 and 8 consisting of a non-magnetic material are provide at the spacing between the permanent magnets.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY In the present invention, a conductive fluid such as a high-temperature, high-speed plasma (mainly combustion gas such as kerosene, heavy oil, and coal), a molten metal (multiphase flow of liquid and gas) and the like crosses the magnetic field. Magnetohydrodynamic power generation (Magneto-hydrodynam), which tries to obtain electric power directly by using electromotive force generated when moving
ic Power Generation, hereinafter referred to as MHD power generation).

[0002]

2. Description of the Related Art Conventionally, for example, a power generation passage having a rectangular cross section is used, and a magnetic field B is applied to a flow path composed of two plate electrodes facing each other and an insulating wall to accelerate a conductive fluid. v
When the current is flown at, a Lorentz electromotive force of v × B per unit length is generated in the direction orthogonal to v and B according to Fleming's right-hand rule, so that a potential difference is generated between the plate electrodes. This is the principle of MHD power generation.
The D power generation is considered to be one of the direct power generation means like the fuel cell and thermionic power generation because it directly converts the energy contained in the fluid into electric energy.

FIG. 2 is a side view of essential parts showing an example of a conventional magnetic field generator used for MHD power generation. In FIG. 2, reference numeral 1 is a yoke, and 2 is a side yoke, which are made of a soft magnetic material such as a soft iron plate, and are arranged so as to face each other in parallel so that the overall cross-sectional shape is a square or a rectangle. To configure. Reference numeral 3 denotes a permanent magnet, which is formed to have a rectangular cross section and is magnetized in the height direction (thickness direction) so that the different poles face each other across the flow path 4 of the conductive fluid. It is fixed to the inner peripheral surface of the yoke 1.

With the above structure, if the conductive fluid is made to flow in the direction orthogonal to the paper surface, the above-mentioned MHD power generation can be performed by the action of the magnetic field of the permanent magnet 3.

[0005]

The electromotive force obtained in MHD power generation is, as described above, the velocity v of the conductive fluid,
It is proportional to the magnetic field B, that is, the magnetic flux density. Therefore, if the velocity v of the conductive fluid is constant, the magnitude of the electromotive force depends on the magnetic flux density of the permanent magnet 3 in the flow path 4.
However, the magnetic flux density due to the permanent magnets 3 is not uniform in the flow path 4, and normally becomes lower as the position is vertically separated from the axis of the flow path 4.

FIG. 3 is a diagram showing the relationship between the vertical position and the horizontal magnetic flux density from the axis in the flow path 4 in FIG. In this case, the diameter of the channel is 65 mm. As indicated by curve b in FIG.
Although it is slightly less than 00G, it is recognized that it decreases to 1500G around the flow path 4 (see FIG. 2). Therefore, there is a difference in the magnitude of the electromotive force obtained depending on the position in the flow path 4 in the vertical direction. In other words, in the magnetic field generator shown in FIG. 2, the magnetic flux density distribution in the flow path 4 is non-uniform. , MHD has a problem that power generation efficiency is low. On the other hand, in order to make the vertical magnetic flux density distribution in the flow path 4 uniform, it is conceivable to increase the width dimension of the permanent magnet 3 (vertical dimension in FIG. 2). It is necessary to increase the thickness of the yoke 1 and the side yoke 2 and the like to increase the width dimension of the magnet 3, which leads to an increase in the size of the entire apparatus and the utilization of the magnetic energy product of the permanent magnet 3. There is a problem of reducing efficiency.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems existing in the above-mentioned prior art and to provide a magnetic field generator for magnetohydrodynamic power generation which has a uniform magnetic flux density distribution in the flow path of a conductive fluid and has high power generation efficiency. And

[0008]

In order to achieve the above object, in the present invention, a flow path for a conductive fluid is formed on the inner peripheral surface of a yoke formed so that two sets of parallel sides exist in a cross section. In a magnetic field generator for magnetohydrodynamic power generation, wherein at least one pair of permanent magnets is provided so that the different poles face each other with the first pole magnet generating a main magnetic field including a central axis of a flow path of a conductive fluid. A second permanent magnet that generates a sub magnetic field is provided on the inner peripheral surface of the yoke that is orthogonal to the yoke on which the first permanent magnet is provided and that is provided on both sides of the plane and that is orthogonal to the plane. And the second through
The technical means of forming the magnetic pole of the permanent magnet on the side of the flow path to be the same as the magnetic pole of the adjacent first permanent magnet.

In the present invention, a dividing plate made of a non-magnetic material can be provided in the gap between the permanent magnets.

[0010]

With the above structure, the magnetic flux density distribution in the flow path is made uniform and the power generation efficiency can be improved.

[0011]

1 is a side view of an essential part of an embodiment of the present invention, in which the same parts are designated by the same reference numerals as in FIG. Figure 1
The yoke 1 and the side yoke 2 are, for example, SS
400, the thickness is 10 mm and the width is 110 mm.
mm and 140 mm, and joined together by bolts (not shown) so that the cross section becomes rectangular. Note that the flow path 4 for the conductive fluid has a diameter of 65 m as in FIG.
m.

Next, 5 is a first permanent magnet for generating a main magnetic field, which is a rare earth / iron / boron permanent magnet (made by Hitachi Metals).
HS37BH) has a width of 21 mm and a height of 29 mm and is magnetized in the height direction to form the flow path 4
It is provided on the inner peripheral surface of the yoke 1 so that the different poles face each other with the pole sandwiched therebetween. Reference numeral 6 denotes a dividing plate, which is made of, for example, aluminum and has a width dimension of 8 mm and a height dimension of 29 mm, and is provided between the first permanent magnets 5 and 5. That is, the split plate 6 is fixed to the yoke 1 by bolts (not shown), and the first permanent magnets 5 and 5 are fixed to the yoke 1 so as to sandwich the split plate 6 via, for example, an epoxy adhesive. ..

Reference numeral 7 is a second permanent magnet that generates a sub-magnetic field, and is a rare earth / iron / boron permanent magnet (HS manufactured by Hitachi Metals).
37BH), width dimension 10mm, height dimension 12
It is formed on the inner peripheral surface of the side yoke 2 so that the same poles face each other across the flow path 4 while being formed in the height direction. The permanent magnets 5 and 7 may have a maximum magnetic energy product different from that described above. Numeral 8 is a dividing plate, which is made of aluminum, for example, and has a width of 20 mm,
It is formed with a height of 12 mm and is provided between the second permanent magnets 7, 7. The magnetic pole of the second permanent magnet 7 on the flow path 4 side is formed to be the same as the magnetic pole of the adjacent first permanent magnet 5.
The means for fixing the second permanent magnet 7 and the division plate 8 to the side yoke 2 is the same as the means for fixing the first permanent magnet 5 and the division plate 6 to the yoke 1.

The result of measuring the magnetic flux density in the horizontal direction at the position in the vertical direction from the axis in the flow path 4 with the above configuration will be described. The curve a in FIG. 3 corresponds to the structure shown in FIG. Figure 3
As is clear from the above, according to the present invention, the magnetic flux density is 3 from the axis of the flow path 4 (see FIG. 1) to the outer peripheral portion.
Values around 300 G are shown, indicating that the distribution is extremely uniform.

As shown in FIG. 1, by providing the first permanent magnets 5 and 5 for generating the main magnetic field on both sides of the dividing plate 6, the magnetic flux is distributed in a relatively wide range of the flow path 4. It is recognized that the magnetic flux becomes relatively linear by providing the second permanent magnets 7 and 7 that generate the auxiliary magnetic field. That is, FIG.
In the conventional one shown in Fig. 3, the magnetic flux between the permanent magnets 3 is bulged outward in a circular arc or curved shape in a portion closer to the upper and lower outer circumferences of the flow path 4, so that the magnetic flux density in the horizontal direction decreases. To do. On the other hand, in the case of the present invention, the second permanent magnets 7, 7 for generating the auxiliary magnetic field are provided, and their magnetic poles are formed to be the same as the magnetic poles of the adjacent first permanent magnets 5, 5. Therefore, it is recognized that the magnetic flux can be prevented from bulging outward in the vicinity of the upper and lower outer peripheries of the flow path 4, and the linearity of the magnetic flux can be promoted.

[0016]

EFFECTS OF THE INVENTION Since the present invention has the structure and operation as described above, the magnetic flux density in the flow path of the conductive fluid is uniform and has a high level from the position of the axis of the flow path to the position of the outer circumference. Therefore, the power generation efficiency can be significantly improved.

[Brief description of drawings]

FIG. 1 is a side view of an essential part showing an embodiment of the present invention.

FIG. 2 is a side view of essential parts showing an example of a conventional magnetic field generator used for MHD power generation.

FIG. 3 is a diagram showing the relationship between the position in the vertical direction from the axis of the flow path 4 in FIGS. 1 and 2 and the magnetic flux density in the horizontal direction.

[Explanation of symbols]

 4 flow path 5 first permanent magnet 7 second permanent magnet

Claims (2)

[Claims] 1. At least one pair of permanent magnets are provided on an inner peripheral surface of a yoke formed to have two parallel sides in a cross section so that different poles face each other with a flow path for a conductive fluid interposed therebetween. In the magnetic field generator for magnetohydrodynamic power generation, the first permanent magnet that generates a main magnetic field is provided with a gap between each of the planes including the central axis of the flow path of the conductive fluid. The second permanent magnet for generating the sub-magnetic field is provided on the inner peripheral surface of the yoke orthogonal to the above-mentioned yoke with a gap between each of the planes orthogonal to the plane, and the flow of the second permanent magnet is A magnetic field generator for magnetohydrodynamic power generation, wherein the magnetic pole on the road side is formed to be the same as the magnetic pole of the adjacent first permanent magnet. 2. The magnetic field generator for magnetohydrodynamic power generation according to claim 1, wherein a dividing plate made of a non-magnetic material is provided in the gap between the permanent magnets.