JP3042064B2 - Self-cooled plasma torch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention particularly relates to an aircraft engine or an automobile engine which accelerates ignition and combustion by injecting a working fluid converted into plasma into a combustor in which a fluid to be burned passes at a supersonic speed. The present invention relates to a self-cooling type plasma torch for ignition, cutting welding, thermal spraying, etc.

[0002]

2. Description of the Related Art A plasma torch as shown in FIG. 4 is known as a technique for igniting a fluid flowing at a supersonic speed, which is said to be difficult to ignite because its flow velocity is too high.

In FIG. 4, a combustor a in which air flows at a supersonic speed
A plasma torch b is provided so as to jet a working fluid for promoting combustion. Inside the plasma torch b, a cathode c and a copper formed of tungsten or the like as an arc generating means are provided. An anode d is formed. Further, a combustor a of the plasma torch b
Is provided with an injection hole e for injecting the working fluid into the combustor a, and a portion not facing the combustor a is provided with an inlet f for the working fluid. Further, cooling water inflow / outflow ports g, i and cooling water outflow ports h, j for cooling the cathode c and the anode d heated by arc discharge, respectively, are provided. The cooling water passing through the inflow / outflow ports g and i exerts a thermal pinch effect of narrowing the arc column at the anode d forming the nozzle portion. Further, a fuel injection nozzle k for injecting hydrogen as a fuel into the supersonic air flow is provided upstream of the supersonic air flow path flowing into the combustor a facing the plasma torch b.

When igniting a supersonic combustion fluid flowing in the combustor a, first, hydrogen as fuel is injected from the fuel injection nozzle k toward a supersonic air flow, and the supersonic air is injected. The stream is mixed with hydrogen to form a supersonic mixed fluid. Then, a working fluid in a state of being used alone or as a mixture thereof from an argon, hydrogen, nitrogen cylinder or the like (not shown) is caused to flow into the inlet f of the working fluid provided in the plasma torch b, and is connected to the cathode c in the plasma torch b. An arc is generated by applying a required voltage to the anode d and the working fluid is heated to an extremely high temperature to form a plasma state, and the generated plasma l is injected into the combustor a through which the supersonic combustion target fluid flows. Let it.

[0005] When the working fluid in the form of plasma is injected into the combustor a in which the mixed fluid flows at a supersonic speed, heat and kinetic energy of the injected plasma l and a chemical reaction accelerating effect accompanying generation of active groups are obtained. The combustion of the mixed fluid flowing at supersonic speed can be promoted, and spontaneous ignition can be performed.

When the above-described plasma torch b is actually applied to an aircraft engine, a diesel engine, or the like, it is desired that the plasma l can always be formed stably and reliably without blowing out the plasma l. Rarely, there is a demand for a device that is as simple as possible and can be miniaturized as much as possible, and that peripheral devices can be simplified.

[0007]

However, in the conventional plasma torch b, since cooling is generally performed using cooling water, the structure for cooling is complicated and it is difficult to reduce the size. In addition, cooling using cooling water has a poor cooling effect because the flow velocity cannot be increased so much. Therefore, the heat pinch effect of the plasma l is small, and the holding force for narrowing the plasma l and holding it stably is weak. When the plasma l is formed in the supersonic flow of air in the air, there is a problem that the plasma l becomes unstable or blows out. Therefore, the conditions (such as the altitude of the aircraft) where the plasma torch b can be used are narrowly limited. There was a problem that was done.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems. The structure of a flow path for cooling by a cooling gas is simplified, thereby making it possible to reduce the size of the cooling nozzle and to improve the efficiency of the injection nozzle. It is an object of the present invention to provide a self-cooling type plasma torch capable of forming good plasma by cooling.

[0009]

According to the present invention, there is provided a cathode rod provided in a nozzle casing, a nozzle port provided between the cathode rod and the nozzle casing, and a nozzle port provided between the cathode rod and a tip end of the cathode rod. An anode injection nozzle which forms a discharge ring passage which communicates with the inside of the front end of the nozzle casing and which forms a front end ring groove, and which communicates with the front end ring groove and extends to the front end side through the inside of the injection nozzle; An introduction flow path, a helical lead-out flow path formed between the injection nozzle and the nozzle casing by a thread provided on an outer peripheral surface of the injection nozzle and communicating with the tip ring groove, and a communication with the introduction flow path A self-cooling type plasma torch characterized by comprising a cooling gas supply path to be cooled and a cooling gas discharge path communicating with the spiral outlet path.

[0010]

The cooling gas introduced from the cooling gas supply path into the introduction flow path of the injection nozzle is guided to the tip ring groove to effectively cool the vicinity of the nozzle opening at the tip of the injection nozzle, and thereafter spirally led out. After the injection nozzle is further cooled from the outer periphery through the flow path, it is discharged to the outside from the cooling gas discharge path. The effective cooling of the vicinity of the nozzle opening and the cooling of the entire injection nozzle due to the high-speed flow of the cooling gas through the spiral outlet channel effectively cools the injection nozzle and increases the thermal pinch effect of the plasma. , The plasma is stabilized.

[0011]

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

FIG. 1 shows an embodiment of the present invention. As shown, a nozzle body 1 constituting a plasma torch is defined by a cylindrical nozzle casing 4 attached to a passage 3 of a combustor 2. Is formed. In the nozzle casing 4, a predetermined length is extended in the axial direction to the axial center portion,
A cylindrical cathode rod 5 constituting an arc generating electrode is provided. At the tip of the cathode rod 5, a cathode 6 formed of a metal, for example, hafnium, which promotes the formation of a high melting point oxide film on the surface thereof is formed. The cathode 6 may be formed by using zirconium, rhenium, yttrium or the like having the same characteristics as hafnium alone or as a composite material.

An injection nozzle 8 constituting an anode 7 of an arc generating electrode is provided between the nozzle casing 4 and the cathode rod 5 with a predetermined gap from the cathode 6.
An ejection passage 9 through which a working fluid 26 passes is formed in a gap between the cathode 6 and the anode 7 constituting the arc generating electrode,
The ejection passage 9 is connected to a nozzle port 10 formed at the tip of the ejection nozzle 8 located on the axis of the cathode rod 5.

A ring-shaped supply passage 11 is formed on the outer periphery of the upstream side of the cathode 6 so as to surround the cathode 6, and a working fluid supply passage is provided upstream of the supply passage 11 through a passage 11 ′. The tube 12 is connected and the cathode 6 of the supply passage 11 is connected.
A supply port 13 communicating with the ejection passage 9 and a swirl passage 13 ′ for giving swirl to the plasma 27 are formed at a lower end extending to the vicinity of the tip of the nozzle.

The injection nozzle 8 constituting the anode 7 is supported by the nozzle casing 4 via an anode block 14. When the injection nozzle 8 and the nozzle casing 4 are combined, the tip ends thereof are separated. A tip ring groove 15 is formed therebetween.

The injection nozzle 8 has an insertion hole 16 for the cathode rod 5 at the axial center as shown in FIGS. 2 and 3, and has a nozzle port 10 at the tip. Injection nozzle 8
An inner groove 17 is formed on the inner periphery on the side opposite to the front end (upper side), and an outer groove 18 is formed on the outer side so as to be concentric with the nozzle port 10. A plurality of introduction flow paths 19 communicating with the tip ring groove 15 are provided.

A thread 2 is provided on the outer peripheral surface of the injection nozzle 8.
0 is formed, and when the injection nozzle 8 is fitted to the nozzle casing 4, the screw lead 20 and the nozzle casing 4 form a spiral lead-out flow path 21 communicating the outer groove 18 and the tip ring groove 15. Is formed.

As shown in FIG. 1, a cooling gas supply passage 23 connected to a supply pipe 22 communicates with the upstream side of the inner groove 17, and a discharge pipe 24 is connected upstream of the outer groove 18. The cooling gas discharge path 25 communicates. Reference numeral 28 denotes a cooling gas composed of helium, hydrogen, oxygen, nitrogen, or the like.

In the above embodiment, the working fluid supply pipe 1
2 to supply the working fluid 26 at high pressure and supply pipe 2
The cooling fluid 28 is supplied from 2.

The high-pressure working fluid 26 supplied from the working fluid supply pipe 12 is supplied from the passage 11 ′ to the ring-shaped supply passage 1.
, The cathode rod 5 is cooled while passing through
The gas is guided to the jet flow path 9, passes through the arc generating electrodes 6, 7, and is turned into plasma. The generated plasma 27 is accelerated by the nozzle port 10 and injected so as to enter the combustor 2 deeply.

The cooling gas 28 supplied from the supply pipe 22 to the cooling gas supply path 23 is guided to the tip ring groove 15 through the inner groove 17 and the introduction flow path 19 of the injection nozzle 8 constituting the anode 7. In the meantime, particularly the inside tip portion of the injection nozzle 8 is intensely cooled, and then the entire injection nozzle 8 is cooled from the outer periphery while passing through the spiral lead-out flow path 21, and then the outer groove 18,
The cooling gas is discharged outside through a cooling gas discharge passage 25 and a discharge pipe 24.

As described above, the injection nozzle 8 is intensely cooled by the cooling gas 28 passing through the introduction flow path 19, the tip ring groove 15, and the spiral discharge flow path 21, so that the nozzle port 1
By increasing the thermal pinch effect due to zero, it is possible to form a high-density plasma 27 that is well narrowed down as shown in FIG.

In the above embodiment, the injection nozzle 8 can be effectively cooled with a simple structure including the introduction flow path 19, the tip ring groove 15, and the spiral discharge flow path 21 in the injection nozzle 8. Therefore, it is possible to reduce the size of the plasma torch as a whole, which facilitates application to an aircraft, a diesel engine, or the like.

Further, by adjusting the cooling temperature of the cooling gas 28, a high density plasma 27 can be formed stably.

It should be noted that the present invention is not limited only to the above-described embodiment, and it is needless to say that various changes can be made without departing from the scope of the present invention.

[0026]

According to the above-described self-cooling type plasma torch of the present invention, the cooling gas is introduced into the tip ring groove through the introduction flow passage formed in the injection nozzle, thereby cooling the inside tip of the injection nozzle. After that, since the entire injection nozzle is further cooled from the outer periphery by guiding to the spiral outlet flow path, effective cooling around the nozzle opening of the injection nozzle,
By improving the cooling effect by the cooling gas flowing at high speed through the spiral outlet flow path, the injection nozzle is cooled well, the thermal pinch effect of the plasma is increased, and the excellent effect of stabilizing the plasma is improved. I can play.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention.

FIG. 2 is a side view showing details of the injection nozzle of FIG. 1;

FIG. 3 is a longitudinal sectional view of the injection nozzle of FIG. 2;

FIG. 4 is a partial sectional view showing an example of a conventional plasma torch.

[Explanation of symbols]

 Reference Signs List 4 Nozzle casing 5 Cathode rod 8 Injection nozzle (anode) 9 Injection passage 10 Nozzle port 15 Tip ring groove 19 Introductory passage 20 Thread 21 Spiral outlet passage 23 Cooling gas supply passage 25 Cooling gas discharge passage

Continuation of the front page (72) Inventor Toshio Irisawa 1 Shin-Nakahara-cho, Isogo-ku, Yokohama-shi, Kanagawa Pref. Ishikawajima-Harima Heavy Industries Co., Ltd. Technical Research Institute 4-206399 (JP, A) Japanese Translation of PCT International Publication No. Hei 3-501467 (JP, A) Japanese Utility Model Hei 1-96274 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H05H 1/28 B23K 10/00 F02P 23/04 H05H 1/34

Claims (1)

(57) [Claims] 1. A cathode rod provided in a nozzle casing, and an ejection passage provided between the cathode rod and the nozzle casing and communicating with a nozzle port between the cathode rod and a tip end of the cathode rod. An anode injection nozzle forming a tip ring groove between the tip ring and the inside of the nozzle casing; an introduction flow path communicating with the tip ring groove and extending from the inside of the injection nozzle to a tip end side; A spiral outlet channel formed between the injection nozzle and the nozzle casing by a thread having an outer peripheral surface of the injection nozzle communicating with the groove, a cooling gas supply channel communicating with the introduction channel, A self-cooling type plasma torch characterized by comprising a cooling gas discharge path communicating with a spiral lead-out flow path.