JP3380822B2 - Magnetic field generator for magnetohydrodynamic power generation - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION In the present invention, a conductive fluid such as high temperature, high speed plasma (mainly combustion gas such as kerosene, heavy oil and coal), molten metal (mixed phase flow of liquid and gas) crosses the magnetic field. Magnetohydrodynamic power generation (Magneto-hydrodynam) that tries to directly obtain electric power 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 constituted by two plate electrodes facing each other and an insulating wall to accelerate a conductive fluid. v
When flowing at, a Lorentz electromotive force of v × B per unit length is generated in a 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. 4 is a side view of essential parts showing an example of a conventional magnetic field generator used for MHD power generation. In FIG. 4, 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. 5 is a diagram showing the relationship between the vertical position from the axis in the flow path 4 and the horizontal magnetic flux density. The conventional one shown in FIG. 4 and an embodiment of the present invention described later. Is also shown. In this case, the diameter of the channel 4 is 72 mm
And As shown by the curve d in FIG. 5, in the conventional device shown in FIG. 4, the magnetic flux density in the horizontal direction is 4800 G on the axial line, while the magnetic flux density around the flow path 4 (see FIG. 4) is 4000 G. It can be seen that it drops to a strong level.

Therefore, there is a difference in the magnitude of the electromotive force obtained depending on the vertical position in the flow path 4, in other words, in FIG.
In the magnetic field generator shown in (1), since the magnetic flux density distribution in the flow path 4 is non-uniform, there is a problem that the power generation efficiency of the MHD 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. 4).
Increasing the width of the permanent magnet 3 in this way requires increasing the thickness of the yoke 1 and the side yoke 2 and the like, which leads to an increase in the size of the entire apparatus and
There is a problem that the utilization efficiency of the magnetic energy product of the permanent magnet 3 is reduced.

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

[0009]

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. A pair of main permanent magnets for generating a main magnetic field are provided so that the different poles face each other with the opposite poles sandwiched between the inner peripheral surface of another yoke orthogonal to the yoke having the main permanent magnet and the side surface of the main permanent magnet. An auxiliary permanent magnet formed in a flat plate shape and magnetized in the thickness direction is interposed so as to be in close contact with each of the surfaces, and one edge of these auxiliary permanent magnets has a magnetic pole end surface of the main permanent magnet. The technical means of forming a magnetic pole on the side of the auxiliary permanent magnet that is in contact with the main permanent magnet with the same pole as the magnetic pole of the end surface of the main permanent magnet so as to project from the side toward the flow path side of the conductive fluid.

In the present invention, the other end of the auxiliary permanent magnet can be formed so as to be located closer to the flow path of the conductive fluid than the contact end face of the main permanent magnet with the yoke.

[0011]

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

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a side view of an essential part showing a first embodiment of the present invention, and the same parts are designated by the same reference numerals as those in FIG.
In FIG. 1, the yoke 1 and the side yoke 2 have a thickness of 25 mm and a width of 160 mm, respectively, according to SS400, for example.
mm and 155 mm, and joined together by bolts (not shown) so that the cross section becomes square. Note that the flow path 4 for the conductive fluid has a diameter of 7 mm as in FIG.
Form to 2 mm.

Next, 5 is a main permanent magnet for generating a main magnetic field in the flow path 4, and a width dimension (see FIG. In the vertical direction) and the height dimension (horizontal dimension in FIG. 1) of 40 mm, and are magnetized in the height direction so that different poles face each other across the flow path 4. It adheres to the inner peripheral surface of 1.

Reference numeral 6 denotes an auxiliary permanent magnet, which is made of the same permanent magnet material as the main permanent magnet 5 and has a width dimension (horizontal dimension in FIG. 1) of 55 mm and a thickness dimension (vertical dimension in FIG. 1). Is formed in a plate shape of 15 mm, magnetized in the thickness direction, and fitted between the inner peripheral surface of the side yoke 2 and the side surface of the main permanent magnet 5. One end edge of the auxiliary permanent magnet 6 projects 25 mm from the magnetic pole end surface of the main permanent magnet 5 to the flow path 4 side, and the magnetic pole of the auxiliary permanent magnet 6 on the side in contact with the main permanent magnet 5 is the main permanent magnet. It is provided so as to have the same pole as the magnetic pole of the end surface of the magnet 5. Further, the other end edge portion of the auxiliary permanent magnet 6 is formed so as to exist at a position 10 mm closer to the flow path 4 side from the other magnetic pole end surface of the main permanent magnet 5.

FIG. 2 is a side view of an essential part showing a second embodiment of the present invention, and the same parts are designated by the same reference numerals as those in FIG. In FIG. 2, the other end of the auxiliary permanent magnet 6 is the same as that shown in FIG. 1 except that it is formed so as to be in the same plane as the other magnetic pole surface of the main permanent magnet 5.

FIG. 3 is a side view of an essential part showing a third embodiment of the present invention, and the same parts are designated by the same reference numerals as those in FIGS. 1 and 2. In FIG. 3, the auxiliary permanent magnet 6 is made of the same permanent magnet material as the main permanent magnet 5 and has a width of 15 mm.
It is formed to have a thickness of 10 mm, magnetized in the thickness direction, and fixed to the inner peripheral surface of the side yoke 2. A space of 20 mm is provided between the auxiliary permanent magnets 6 and 6, and a magnetic pole having the same pole as the main permanent magnet 5 in the vicinity is provided on the flow path 4 side.

The result of measuring the magnetic flux density in the horizontal direction at the vertical position from the axis in the flow path 4 with the above structure will be described with reference to FIG. In FIG.
The curves a, b and c are shown in FIGS.
It corresponds to the configuration shown in. As can be seen from FIG. 5, the magnetic flux density in the horizontal direction of each of the curves a, b and c is higher than that of the conventional curve d. However, the curve c has a non-uniform distribution from the axis of the flow path 4 (see FIG. 3) to the outer circumference. On the other hand, the curves a and b show that the distribution is uniform, and in particular, in the curve a, the magnetic flux density is 6 over the entire area of the flow path 4 (see FIG. 1).
A value of 000 G or more is shown.

This is as shown in FIGS.
An auxiliary permanent magnet 6 is provided between the main permanent magnet 5 and the side yoke 2.
It is considered that this is due to the fact that the magnetic flux becomes relatively linear due to the provision of. That is, in the conventional structure shown in FIG. 4, the magnetic flux between the permanent magnets 3, 3 bulges outward in an arc shape or a curved shape in a portion closer to the upper and lower outer circumferences of the flow path 4, so that the magnetic flux in the horizontal direction is increased. The magnetic flux density decreases. On the other hand, according to the present invention, the main permanent magnet 5
Since the auxiliary permanent magnet 6 is provided on the side surface of the main magnetic pole and the magnetic pole on the side in contact with the main permanent magnet 5 is formed to be the same pole as the magnetic pole on the side surface of the main permanent magnet 5, It is recognized that the bulging of the magnetic field can be prevented and the linearity of the magnetic flux can be promoted.

[0019]

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. The effect is that the power generation efficiency can be significantly improved.

[Brief description of drawings]

FIG. 1 is a side view of essential parts showing a first embodiment of the present invention.

FIG. 2 is a side view of essential parts showing a second embodiment of the present invention.

FIG. 3 is a side view of an essential part showing a third embodiment of the present invention.

FIG. 4 is a side view of essential parts showing an example of a magnetic field generator used for conventional MHD power generation.

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

[Explanation of symbols]

4 channels 5 Main permanent magnet 6 Auxiliary permanent magnet

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Claims (2)

(57) [Claims] 1. A pair of main magnetic field generators for generating different magnetic poles on the inner peripheral surface of a yoke formed so that there are two sets of parallel sides in a cross section so that different poles face each other with a flow path for a conductive fluid interposed therebetween. A main permanent magnet is provided, and an auxiliary permanent magnet formed in a flat plate shape and magnetized in the thickness direction between the inner peripheral surface of another yoke orthogonal to the yoke provided with this main permanent magnet and the side surface of the main permanent magnet. A magnet is interposed so as to be in close contact with each of the above-mentioned surfaces, and one edge of these auxiliary permanent magnets projects from the magnetic pole end surface of the main permanent magnet to the flow path side of the conductive fluid, and the auxiliary permanent magnet. 2. The magnetic field generator for magnetohydrodynamic power generation, wherein the magnetic pole on the side in contact with the main permanent magnet is formed to be the same pole as the magnetic pole on the end face of the main permanent magnet. 2. The electromagnetic fluid according to claim 1, wherein the other end of the auxiliary permanent magnet is formed so as to be present on the flow path side of the conductive fluid with respect to the contact end face of the main permanent magnet with the yoke. Magnetic field generator for power generation.