JPH08223902A - Disk-shaped mhd generator - Google Patents

Abstract

PURPOSE: To obtain a disk-shaped MHD generator which prevents a ceramic insulating wall from being cracked due to a thermal stress by a method wherein a torus-shaped electrode on the side of a discharge dust is formed so as to be divided in the circumferential direction. CONSTITUTION: Ceramic insulating walls 6 are interposed between a torus-shaped electrode 4 and a torus-shaped electrode 5, and edges of every insulating wall 6 are tapered. The torus-shaped electrode 5 is divided into a plurality of parts in the circumferential direction in dividing parts 5a. The electrode 5 is moved in the radial direction due to the slip of a mounting bolt for the electrode with reference to the expansion in the radial direction of every ceramic insulating wall 6 so as to absorb a thermal stress, and a thermal stress due to thermal expansion is not generated. Consequently, it is possible to prevent ceramic insulating walls from being cracked due to the thermal stress.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of an annular electrode used in a magnetohydrodynamic generator (hereinafter referred to as MHD generator).

[0002]

2. Description of the Related Art Generally, as shown in FIG. 2, a disk type MHD generator uses a working gas 10 which diffuses radially from a central portion, and a radial direction from a gas inflow duct 2 via a power generating unit 1. The working gas 10 passes through to the gas exhaust duct 3. Of these, in the power generation unit 1, FIG.
Also has a ring-shaped anode 4 and a ring-shaped cathode 5, and a working gas 10 is provided between the anode 4 and the cathode 5.
An electromagnet 7 that allows the magnetic flux B to pass in a direction perpendicular to is provided.

A ceramic insulating wall 6 for passing a working gas is provided between the anode 4 and the cathode 5 in the power generation section 1 as shown in FIGS. In FIG. 3, 8 is a water-cooled voltage terminal piece connected to the electrode.

[0004]

The ceramic insulating wall 6 between the electrodes 4 and 5 which is also the flow passage of the working gas 10 in the power generation section 1 is formed by the taper edge 6a with the electrodes 4 and 5 and the mounting bolt 9. It has a structure that can be firmly tightened. Therefore, the thermal expansion when the ceramics insulating wall 6 reaches a high temperature is restricted, and a large thermal stress is generated,
The ceramic insulating wall 6 may be damaged.

The present invention has been made in view of the above problems, and an object thereof is to provide a disk type MHD generator in which cracks due to thermal stress of a ceramic insulating wall are prevented from occurring.

[0006]

The present invention which achieves the above object is characterized by the following constitution. A power generation unit is provided between an inflow duct in the central part for allowing the working gas to flow in and an exhaust duct for discharging the working gas radially diffused from the central part, and the central part side and the exhaust duct side of the power generating part are provided. In the MHD generator formed by a pair of annular electrodes via an insulating wall, the annular electrode on the side of the exhaust duct is formed by being divided in the circumferential direction.

[0007]

[Function] The reason why the insulating wall is constrained is the shape of the annular electrode, and since the radially arranged power generating portions uniformly thermally expand, the annular electrode restricts this elongation.
If the annular electrode is divided, it can move in the radial direction according to the thermal expansion, and the restraint of the insulating wall can be prevented.

[0008]

EXAMPLE An example of the present invention will now be described with reference to FIG. In FIG. 1, the same parts as those in FIG. 4 are designated by the same reference numerals. FIG. 1 is a plan view of the power generation section of the disk-type MHD generator of this embodiment. A ceramic insulating wall 6 is interposed between the annular electrodes 4 and 5, and the end of this insulating wall 6 is shown. Has a tapered edge 6a. The annular electrode 5 is circumferentially divided into a plurality of divided portions 5a, and the electrode 5 is radially divided by the sliding of the electrode mounting bolt (bolt 9 in FIG. 3) against the radial extension of the ceramic insulating wall 6. It is possible to move in the direction and absorb the thermal stress, and the thermal stress due to thermal elongation is not generated.

To explain the operation with reference to FIGS. 1 and 3,
At a high temperature of about 2000 ° K, the electrically conductive working gas 10 flows into the apparatus from the inflow duct 2 and generates a voltage between the annular anode electrode 4 and the divided annular cathode electrode 5, and the working gas is generated after power generation. Is discharged from the discharge duct 3. The voltage generated at each of the electrodes 4 and 5 is taken out from the water-cooled voltage terminal strip 8 as a current. In this case, the annular electrodes 4 and 5 are cooled by the cooling water, but the ceramic insulating wall 6 disposed between the annular electrodes 4 and 5 is heated to a high temperature (1200 ° C. to 1300 ° C.) by heat from the hot working gas 10. (° C), thermal expansion occurs in the circumferential and radial directions. In this case, it is possible to move the ceramic insulating wall 6 in the radial direction by the sliding of the mounting bolt 9 of the water-cooled voltage terminal strip 8 without restraining the insulating wall 6. As a result, thermal stress is not generated by restraining the thermal expansion of the insulating wall 6, and damage to the insulating wall 6 can be prevented.

Although the above description is based on the closed cycle MHD power plant, it can be naturally applied to the open cycle MHD power plant.

[0011]

As described above, according to the present invention, the structure in which the ring-shaped electrode is divided allows the ring-shaped electrode to absorb the thermal expansion generated as the temperature of the insulating wall rises. The generation of thermal stress that restrains the thermal expansion of the insulating wall is eliminated, and damage to the insulating wall can be prevented.

[Brief description of drawings]

FIG. 1 is a partial plan view of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a disk type MHD generator.

FIG. 3 is a partial cross-sectional view mainly showing a power generation unit.

FIG. 4 is a partial plan view of a conventional example taken along the line AA of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Power generation part 2 Inflow duct 3 Exhaust duct 4,5 Ring-shaped electrode 5a Dividing part 6 Insulating wall 6a Tapered edge 9 Mounting bolt

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Katsuo Hashizaki 2-5-1, Marunouchi, Chiyoda-ku, Tokyo Sanryo Heavy Industries Co., Ltd. (72) Inventor Naoki Omura 1-1, Atsunoura-machi, Nagasaki-shi, Nagasaki Mitsubishi Heavy Industries Nagasaki Shipyard Co., Ltd.

Claims (1)

[Claims] 1. A power generation unit is provided between an inflow duct in the central portion for allowing the working gas to flow in and an exhaust duct for discharging the working gas radially diffused from the central portion, and the power generation unit is connected to the central portion side. In a MHD generator formed with a pair of annular electrodes on the exhaust duct side through an insulating wall, the annular electrode on the exhaust duct side is formed by being divided in the circumferential direction. Machine.