JPH02188158A - Electromagnetic flow coupler - Google Patents

Abstract

PURPOSE:To reduce the change of flux density and to miniaturize an electromagnetic flow coupler by providing a bending section in the passage of a region where the flux density changes. CONSTITUTION:A ring-shaped flow coupler makes use of a ring-shaped space formed by a passage inner wall 6 and a passage outer wall 5 as its passage. The ring-shaped space is divided circumferentially by a passage pipe 1. An external pole 3 and an exciting coil 2 are arranged outside the passage outer wall 5 surrounding the passage. In this ring-shaped electromagnetic flow coupler at an end section in the passage direction and an exciting coil section the flux density changes steeply. Then, by twisting the passage pipe 1 of the exciting coil section, a bending section is provided. In this way, the distance passing through the exciting coil section along the center of passage is lengthened and the rate of change in flux density apparent against the fluid inside the passage gets reduced. The occurrence of overcurrent can thereby be blocked and the efficiency of the electromagnetic flow coupler improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electromagnetic flow coupler, which is a device for driving liquid metal, and particularly relates to an annular electromagnetic flow coupler that takes into consideration the arrangement of flow channels to improve efficiency. Regarding.

[Conventional technology]

Regarding the influence of the rate of change in the distribution of magnetic flux density at the ends of the flow direction of an electromagnetic flow coupler on the efficiency of the electromagnetic flow coupler, Magneto Hydrodynamics, No. 19,
Volume 2 (1983), pages 211 to 215 (Mag
netohydrodynamics, Vo119,
No. 2 (1983) PP 211-215). However, the magnetic pole structure and flow path structure for improving efficiency are not discussed.

[Problem to be solved by the invention]

The above paper states that the efficiency improves as the rate of change in magnetic flux density at the ends of the electromagnetic flow coupler in the flow direction decreases. Generally, in order to reduce the rate of change in magnetic flux density between magnetic poles, it is possible to make the magnetic poles longer and gradually increase the distance between them. The problem arises that it becomes long.

In addition, especially in the case of an annular electromagnetic flow coupler, since a radial magnetic field is used, the direction of the magnetic field is reversed with respect to the flow direction of the electromagnetic flow coupler, as shown in Figure 2, and even in the excitation coil part. The magnetic flux density distribution changes rapidly. Changes in the magnetic flux density distribution in this excitation coil section also pose a major challenge for improving efficiency.

An object of the present invention is to reduce the rate of change in a region where magnetic flux density changes and to miniaturize an electromagnetic flow coupler as much as possible.

(Means for solving illjl) The above purpose is to solve the flow direction end of the electromagnetic flow coupler or
In an area where the magnetic flux density changes, such as the excitation coil part of an annular electromagnetic flow coupler, a bending part is provided in the flow path so that the length passing through the area where the magnetic flux density changes is effectively increased. This is achieved by This situation is shown in FIG. 3. In FIG. 3, one set of the generator side flow path 7 and the pump side flow path 8 are taken out for simplicity. Bent portions of the flow path are provided at the portion where the excitation coil 2 is sandwiched between the magnetic poles 3 and at the upper and lower ends of the magnetic poles 3.

[Effect]

By providing a bend in the flow path in the region where the magnetic flux density changes, the distance traveled through the region where the magnetic flux density changes effectively increases, so the ratio of change in the apparent magnetic flux density to the fluid in the flow path increases. becomes small, and the generation of eddy currents can be suppressed.

【Example〕

An embodiment of the present invention will be described below with reference to FIG.

Changes in magnetic flux density are a particular problem in annular electromagnetic flow couplers that utilize radial magnetic fields, so an annular electromagnetic flow coupler will be explained as an example. As shown in Fig. 1, the annular electromagnetic flow coupler has two cylinders that are the outer wall 5 and the inner wall 6 of the flow path arranged coaxially, and the annular space formed by these cylinders as the flow path. Make use of it. The annular space is circumferentially divided by flow pipes 1 having high electrical conductivity.

Outside the flow path outer wall 5, an external magnetic pole 3 and an excitation coil are arranged to surround the flow path. In addition, the flow path inner wall 6
An internal magnetic pole 4 is arranged inside. These channel outer wall 5, channel inner wall 6, and excitation coil 2 generate a radially inward or outward magnetic field in the channel. Channel pipe 1
The fluid inside is forced to 1 by an external force! It is called the generator side flow path 7 because it is surrounded by a magnetic field and a flow acts on it, and generates an electromotive force according to Fleming's right-hand rule. On the other hand, on the outside of the flow pipe 1, a current flows due to the electromotive force generated in the generator side flow path 7, and this current receives electromagnetic force from the magnetic field according to Fleming's left-hand rule, and generates a pumping force on the fluid. It is called a pump side flow path 8. FIG. 2 shows an example of the magnetic flux density distribution of an annular electromagnetic flow coupler. As shown in FIG. 2, in an annular electromagnetic flow coupler, the direction of the magnetic field changes as it advances in the flow direction. In particular, the machine direction ends and.

In the excitation coil section, the magnetic flux density changes rapidly, generating eddy currents inside the fluid. In FIG. 1, a bent portion is provided in the flow path pipe 1 at this excitation coil portion, and the generator side flow path 7. By adding a circumferential twist to both the pump-side flow channels, the distance passing through the excitation coil section along the center of the flow channel is increased, and the ratio of change in the apparent magnetic flux density to the fluid inside the flow channel is increased. is made smaller. Although not shown in Figure 1.

By providing similar bent portions at the upper and lower ends of the outer magnetic pole 3, it is possible to reduce the rate of change in the apparent magnetic flux density at the upper and lower ends. Although the present invention has been described above using an annular electromagnetic flow coupler as an example, similar effects can be obtained with an electromagnetic flow coupler configured with a rectangular flow path by providing a bent portion in the flow path.

In addition, in the figure, 9 is the flow of fluid on the generator side, and 10 is the flow of fluid on the pump side.

〔Effect of the invention〕

According to the present invention, the gradient of magnetic flux density attenuation can be reduced without increasing the length of the electromagnetic flow coupler in the flow direction, and the efficiency of the electromagnetic flow coupler can be improved by suppressing the generation of eddy currents.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an embodiment of the present invention, FIG. 2 is a magnetic flux density distribution diagram, and FIG. 3 is a detailed explanatory diagram of the present invention. DESCRIPTION OF SYMBOLS 1... Channel tube, 2... Excitation coil, 3... External magnetic pole, 4... Internal magnetic pole, 5... Channel outer wall, 6... Channel inner wall, 7... Power generation Machine side flow path, 8... Pump side flow path, 9... Generator side fluid flow, 10... Pump side fluid flow. Figure I? rl! 7 Tomu J h & Beggar A

Claims (1)

[Scope of Claims] 1. An electromagnetic flow coupler comprising a plurality of electrically connected flow channels that drive a conductive fluid and an excitation device that generates a magnetic field in a direction perpendicular to the flow channels, comprising: An electromagnetic flow coupler characterized by having a bend in the flow path. 2. The electromagnetic flow coupler according to claim 1, wherein the bent portion is an end portion of an excitation device. 3. The electromagnetic flow coupler according to claim 1, wherein the flow path is annular and formed by a coaxial cylinder. 4. The electromagnetic flow coupler according to claim 3, wherein a part of the flow path has a spiral shape.