JPH06201513A - Constrictor type arc heater - Google Patents

Abstract

PURPOSE:To reduce deterioration of a constrictor disk due to heat by improving the efficiency of cooling of the constrictor disk by cooling water. CONSTITUTION:In a constrictor type arc heater having a construction wherein a constrictor 11 constructed by providing a plurality of constrictor disks 12 in continuity in the axial direction with insulating members 13 interposed therebetween is provided between a cathode and an anode, wherein a cooling channel 18 is provided circularly inside each constrictor disk 12 so that it surrounds a discharge path 3 d formed in the core part of the constrictor 11, and wherein cooling water 10 is led into and out of the cooling channel 18 through a water supply passage and a water discharge passage extending in the direction of the radius of the constrictor disk 12, a fin 19 is formed in projection from the wall surface 18a of the cooling channel 18 so that it does not intercept the flow of the cooling water 10 from the water supply passage to the water discharge passage, and thereby the area of heat exchange is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a restrictor type arc heater.

[0002]

2. Description of the Related Art Conventionally, arc heating has been carried out by blowing a high-temperature plasma stream onto a specimen placed at a required position in a wind tunnel to perform a thermal test (heat resistance test, corrosion test, etc.) on the specimen. Although a wind tunnel test apparatus is known, in recent years, since a thermal test with a large heat capacity has been desired, the arc heating wind tunnel test apparatus tends to be large, and heating for generating a plasma air flow with a large heat capacity is required. A constrictor type arc heater has come to be used as a device.

FIGS. 4 and 5 show an example of the constrictor type arc heater. Basically, a working gas is introduced into a discharge passage 3 formed between a cathode 1 and an anode 2 through a working gas introducing passage 4. 5 to supply the working gas 5 to the cathode 1 and the anode 2
A high-temperature plasma flow 5'is ejected from the nozzle 7 by an arc discharge 6 generated between the cooling flow and the cooling flow via the water supply channel 8 and the drain channel 9 in order to further increase the heat capacity. A constrictor 11 capable of maintaining a low temperature around the discharge path 3 by the cooling water 10 introduced into the path 17 is interposed between the cathode 1 and the anode 2 to increase the distance between the cathode 1 and the anode 2. It is designed to be able to apply large currents and voltages.

That is, in order to apply a large current and a large voltage, it is necessary to lengthen the separation distance between the cathode 1 and the anode 2. However, if the separation distance between the cathode 1 and the anode 2 is simply increased, arc discharge will occur. 6 cannot be stabilized. However, since the electrical conductivity of gas increases as the temperature increases, if the surroundings of the discharge path 3 are cooled by surrounding the discharge path 3 with the constrictor 11, the arc discharge 6 (current) causes the discharge path 3 having a low temperature. Discharge path 3 avoiding the peripheral wall of 3
Will flow near the axis of the
The temperature rises near the axis of the discharge path 3 due to Joule heat, and the electric conductivity increases, so that the arc discharge 6 more easily flows to the axis of the discharge path 3 and the arc discharge 6 is stabilized. Will be planned.

Since the constrictor 11 must maintain an appropriate potential gradient in the axial direction of the discharge path 3 (left-right direction in FIG. 4), the disc-shaped metal constrictor disk 12 is used. A plurality of sheets are continuously combined in the axial direction while being insulated from each other by interposing an insulating member 13, and the rear position of the cathode 1 and the front position of the anode 2 in the jetting direction of the plasma airflow 5 '. The relatively long connecting bolts 1 extending in the axial direction of the constrictor 11 are formed by connecting the flange members 14 and 15 respectively arranged in the
By fastening at 6, the respective constrictor disks 12 and the insulating member 13 combined as the constrictor 11 are sandwiched and integrally sandwiched.

[0006]

However, in the above-mentioned conventional constrictor type arc heater, the discharge path 3 is used.
The cooling efficiency is poor only by cooling the cooling water 10 by flowing it through the annular cooling passage 17 formed in the periphery, and although the periphery of the discharge passage 3 can be cooled and the arc discharge 6 can be stabilized,
Since the entire restrictor disk 12 constituting the restrictor 11 could not be sufficiently cooled, there was a problem that the restrictor disk 12 was severely deteriorated by heat.

The present invention has been made in view of the above situation, and an object thereof is to reduce the deterioration of the constrictor disk due to heat by improving the cooling efficiency of the constrictor disk by the cooling water.

[0008]

According to the present invention, a constrictor having a plurality of constrictor disks connected in the axial direction via an insulating member is provided between a cathode and an anode, and the axial center of the constrictor is provided. Has a ring-shaped cooling passage inside each of the constrictor disks so as to surround the discharge passage formed in the portion, and the cooling water is supplied to the cooling passage through a water supply passage and a drain passage extending in the radial direction of the constrictor disc. In a constrictor-type arc heater configured to introduce and discharge a fin, a fin is formed on the wall surface of the cooling channel so as not to block the flow of cooling water from the water supply channel to the drain channel. The present invention relates to an arc heater and a constrictor type arc heater characterized in that a notch is formed at a position facing the water supply passage of the fin.

[0009]

Therefore, in the present invention, when the cooling water is introduced from the water supply passage, the cooling water sufficiently cools the constrictor disk by heat exchange with the wall surface of the cooling passage and the surface of the fins, and the cooling water is passed through the drainage path to the outside of the constrictor disk. Is discharged to.

Further, if the notch is formed at a position facing the water supply passage of the fin, the cooling water introduced from the water supply passage mainly passes through the notch so that the cooling flow does not receive resistance. It reaches the inner circumference of the passage and spreads evenly inside the cooling passage.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 3 show an embodiment of the present invention, in which parts designated by the same reference numerals as those in FIGS. 4 and 5 represent the same parts.

As shown in the figure, in the present embodiment, a conventional cooling passage 17 (see FIGS. 4 and 5) formed only in the vicinity of the discharge passage 3 inside the constrictor disk 12 constituting the constrictor 11 is used. A cooling passage 18 is formed in an annular shape so as to surround the discharge passage 3 and expands to the outer peripheral side in the radial direction of the constrictor disk 12.
On the wall surface 18a on the front side (right side in FIG. 1), fins 19 are formed so as not to block the flow of the cooling water 10 from the water supply passage 8 to the drain passage 9.

The shape of the fins 19 is the same as that of the cooling channel 1.
8 from the position near the inner circumference of the wall surface 18a on the front side toward the rear side (left side in FIG. 1) and then bent toward the outer circumferential side in the radial direction of the constrictor disk 12, In the present embodiment, a notch 20 extending in the radial direction is formed at a position facing the water supply passage 8 of the fin 19.

As a means for disposing the fins 19 in the cooling flow passage 18, as shown in FIG. 3, for example, a wall surface 18a on the front side of the cooling flow passage 18 and the fins 19 are integrated into a fitting piece 21. It may be divided into separate parts, fitted into the restrictor disk 12 and brazed.

When the cooling water 10 is introduced from the water supply passage 8, the cooling water 10 spreads in the cooling flow passage 18 and heat is exchanged with all the wall surfaces of the cooling flow passage 18 and the surfaces of the fins 19. The constrictor disc 12 is cooled and discharged to the outside of the constrictor disc 12 through the drainage channel 9.

Therefore, according to the above-described embodiment, the fins 19 are formed on the wall surface 18a of the cooling flow passage 18 having the shape expanded toward the outer peripheral side in the radial direction of the constrictor disk 12, whereby the cooling water 10 and the constrictor disk are formed. 1
The heat exchange area with the second side can be sufficiently increased, and the cooling efficiency of the constrictor disk 12 by the cooling water 10 can be significantly improved as compared with the conventional case, so that deterioration of the constrictor disk 12 due to heat can be significantly reduced. can do.

Further, since the notch 20 is formed at a position of the fin 19 facing the water supply passage 8, the cooling water 10 introduced from the water supply passage 8 is provided with no resistance and the inner peripheral side of the cooling flow passage 18 is provided. The cooling water 10 can be evenly distributed in the cooling flow path 18.

The constrictor type arc heater of the present invention is not limited to the above-mentioned embodiment, and the shape of the fins is not limited to the illustrated example, and the scope of the present invention is not deviated. Of course, various changes can be made within.

[0020]

The constrictor type arc heater of the present invention described above can exert various excellent effects as described below.

(I) Since the fins are formed on the wall surface of the cooling passage, the heat exchange area between the cooling water and the constrictor disk side can be increased, and the cooling efficiency of the constrictor disk by the cooling water can be improved more than before. Since it can be greatly improved, deterioration of the constrictor disk due to heat can be significantly reduced.

(II) Since the life of the constrictor disk can be greatly extended by the above (I), a heating test using a constrictor type arc heater can be continuously performed without replacing the constrictor disk. You can

(III) If the notch is formed at a position facing the water supply passage of the fin, the cooling water introduced from the water supply passage can be satisfactorily extended to the inner peripheral side without giving resistance to the cooling water. The cooling water can be evenly distributed in the cooling flow path.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of the present invention.

FIG. 2 is a view taken along the line II-II in FIG.

FIG. 3 is a vertical cross-sectional view showing an example of means for arranging fins in the cooling channel of FIG.

FIG. 4 is a vertical sectional view showing a conventional example.

5 is a cross-sectional view of the constrictor disc of FIG.

[Explanation of symbols]

 1 Cathode 2 Anode 3 Discharge Channel 8 Water Supply Channel 9 Drainage Channel 10 Cooling Water 11 Constrictor 12 Constrictor Disk 13 Insulating Member 18 Cooling Channel 18a Wall Surface 19 Fin 20 Notch

Claims (2)

[Claims] 1. A constrictor comprising a plurality of constrictor disks connected in the axial direction via an insulating member, is provided between a cathode and an anode, and surrounds a discharge path formed in the axial center of the constrictor. As described above, each of the constrictor discs has an annular cooling channel, and the cooling water is introduced into and discharged from the cooling channel via a water supply channel and a drain channel extending in the radial direction of the constrictor disk. A restrictor-type arc heater, wherein fins are formed on the wall surface of the cooling channel so as not to block the flow of the cooling water from the water supply channel to the drain channel. 2. The constrictor type arc heater according to claim 1, wherein a cutout is formed at a position of the fin facing the water supply passage.