KR100505916B1 - Construction of pulse gun and reusable cavity for stability rating test of rocket engine and purging system thereof - Google Patents

Abstract

The present invention relates to a pulse gun, which is an artificial disturbance supply device, and a reusable induction joint device used for the combustion stability confirmation test that must be verified in the development of a rocket engine, and a purging system used therein. The present invention relates to a pulse gun for rocket engine combustion stability evaluation, a reusable joint device and a purging system that can save time / cost due to trial and error, and to develop an engine with high stability and reliability.

Description

Pulse gun and reusable cavity for stability rating test of rocket engine and purging system

The present invention provides a pulse gun, an artificial disturbance supply device, a reusable induction joint device, and a purging system used therefor, for the combustion stability confirmation test, which must be verified when developing a rocket engine. The present invention relates to a pulse gun operation and reusable induction joint device for purging rocket engine combustion stability, and a purging system used therein, which can reduce the time / cost due to a mistake and develop an engine with high stability and reliability. .

The combustion instability of rocket engines is a phenomenon that occurs during almost all rocket engine developments, and is caused by the mutual coupling of the combustion process and the flow inside the combustion chamber. Amplification can cause catastrophic damage to the operation of the engine itself and the entire vehicle system.

The Stability Rating Test (SRT) is a technique for evaluating the combustion stability of rocket engines. In addition to the statistical stability analysis, the most commonly used as dynamic stability analysis is bomb or pulse gun. (pulse gun).

This is to evaluate the combustion stability of the engine by determining whether the pressure vibration in the combustion chamber radiates or attenuates by generating an artificial disturbance as shown in FIG. 1 during the combustion process using a bomb or a pulse gun.

As a device for generating artificial disturbances, a night, which has been widely used in the past, is directly installed in a combustion field of a combustion chamber, and thus is exposed to a high temperature / high pressure flow during a combustion process, thereby predicting a melting point of a material surrounding the initiator. It is difficult to set the exact point of disturbance because it is difficult.

On the other hand, the pulse gun is installed on the outer wall of the combustion chamber and is not directly exposed to the high temperature / high pressure combustion gas, and since the electrical ignition method is generally used, it has an advantage of generating artificial disturbance at a desired time during the combustion process.

Accordingly, the pulse gun is the most widely used in the stability evaluation technique that is commonly used recently.

Although this combustion stability evaluation technique is an essential core technology that must be preceded in the rocket engine development process, it has not been developed in Korea due to the avoidance of technology transfer in developed countries.

In developed countries, the development of rocket engines has undergone combustion stability verification tests during dozens or hundreds of combustion tests, followed by the life test of rocket engines.

Although only a limited amount of artificial pressure wave disturbances are used in Korea, there are no experiments in connection with the combustion phenomenon of the engine.

In the case of pulse guns, less thermal considerations are required than at night, but a purging system is required to prevent the introduction of hot / high pressure gases in the direction of the pulse gun outlet, and the optimum purge flow rate must also be determined according to the size of the combustion chamber.

In other words, in order to apply the pulse gun to rocket engines of various scales, the operating conditions of the engine combustion chamber, that is, the combustion phenomenon, should not be greatly distorted, and the error of the pulse gun caused by the high temperature and high pressure combustion gas from the engine in operation should be avoided. There is a need for a purging system.

In particular, in the case of a small thrust size engine, the operating conditions may be distorted by the purging flow, so it is necessary to pay close attention to this.

The operation of the pulse gun is first used by placing a cavity between the detonator and the combustion chamber, connecting the cavity with the detonator.

The pressure wave transmitted from the detonator and the momentary hot gas cause damage to the contact surface of the adapter for the pulse gun.

In general, for the safety of the operator during operation, the pulse gun adapter and the induction cavity are used in a manner of replacing only the detonation part in a pre-welded state, and thus preventing such damage in order to reuse the pulse gun contact part (adapter and the induction cavity). It is important to maintain safety.

The present invention provides a design / fabrication technique and a test and operation technique of a reusable induction cavity and a pulse gun, which is an artificial disturbance supply device, for a combustion stability confirmation test, which must be verified when developing a rocket engine.

Through this, it is possible to save time / cost due to trial and error in the development of rocket engine, and to develop an engine with high stability and reliability.

Through the design / manufacture and test techniques of this pulse gun, it is possible to provide not only the response characteristics of the engine by a single pressure wave in a single combustion test, but also a device / test technique that can give two or more artificial excitations to the rocket engine test and You can save development costs.

This could be used as a technique to verify the instability characteristics of low-pollution gas turbine combustors, which are becoming a big issue not only in rocket engines but also in developed countries.

A purging system is provided to prevent the inlet of combustion gases from the combustion chamber to the pulse gun, especially on small scale rocket engines, which must not distort the operating conditions of the combustion chamber.

To this end, by separately configuring the purging unit using the orifice in the purging system to be applicable to the engine of various thrust size.

In the case of a pulse gun body, breakage of the body due to the alleged weak explosive force may cause interruption of the test or damage to the combustion chamber equipment due to high / high pressure combustion gas leakage in the combustion chamber.

To prevent this, the pulse gun explosives and the burst resistance of the body are secured and airtightness can be maintained even after use.

Pulse gun induction cavities should generally be available several times, and are welded to the pulse gun adapter to facilitate airtightness.

Thus, the condition after the explosion test at the contacting part of the membrane should be in good condition and airtight as well, and it is necessary to be able to handle the debris generated after the explosion test.

This solves the health of the body so that it can be reused more than once for cost savings and operational safety.

The present invention consists of a pulse gun design / manufacture technology that can generate a pressure wave at a desired time point, and a pressure wave induction device design technology and a test technology to efficiently install a pulse gun in a rocket engine to perform combustion stability test. do.

First, the whole system can be largely divided into a pulse gun unit (A) capable of applying instantaneous pressure through the gunpowder, a pressure induction unit (B) for inducing the pressure to the engine, and a purging system.

Pulse gun portion (A) is one side of the detonation portion 24 to which the connection nut 2 is connected, the airtight portion fixing portion 10 fixes the airtight portion 5 and the fixing pin (6), the electrical connector (7) ) Is installed to receive the electricity supply (4).

It consists of the initiator 9 which is installed inside the initiator 24, the electricity supply 4 for igniting the initiator 9, and the assertive medicine 3 for generating main explosion force by the explosion of the initiator 9 do.

That is, the explosive force supplies a pulse signal of a predetermined voltage / current to the electric supply unit 4 to explode the initiator 9, and the explosive charge 3 explodes by this explosive force to generate a strong pressure instantaneously.

This pressure fills the pulse gun cavity 8 in the pulse gun with high pressure gas, which breaks the membrane 1 blocking the pressure and transmits a momentary pressure wave toward the combustion chamber.

The connecting nut 2 is assembled to the detonation part 24 surrounding the outer side of the capillary drug 3, and the pulse gun is engaged with the pulse gun adapter 13 of the pressure inducing part B, and compresses the membrane 1. It plays a role.

In addition, it is possible to adjust the magnitude of the excitation pressure applied to the engine by adjusting the filling amount and the filling density of the charge drug 3 of the pulse gun.

The membrane 1 serves to protect the pulse gun portion A from the high temperature / high pressure gas that may be introduced from the combustion chamber, and at the same time, the pressure wave is introduced into the engine.

The pressure induction part B for efficiently applying the pulse gun as described above to the rocket engine combustion test is as shown in FIG. 3.

The pressure induction part B is provided with a pulse gun adapter 13 coupled with a pulse gun and a nitrogen purging adapter 16 for preventing a malfunction of the pulse gun by effectively preventing the inflow of combustion gas in the engine.

In addition, an engine adapter 17 for injecting pressure waves into the combustion chamber of the thrust engine is installed upward, and an induction cavity 11 is installed on the opposite side of the pulse gun adapter 13, and the induction cavity 11 One side forms a hemispherical shape 19 and is installed to have a locking jaw 20 on the side of the pulse gun adapter 13 which is a part corresponding to the hemispherical shape 19.

Debris of the membrane 1 due to the explosion pressure inside the pulse gun by treating the shape of the induction cavity 11 in the pressure wave induction apparatus in the opposite direction of the adapter 13 for the pulse gun as shown in FIG. 4. As shown in the dotted line 12 shown in Figs. 3 and 4, collisions occur within the cavity hemisphere 19 along the pulse gun pressure wave trajectory 18, so that a large amount of momentum decreases, so that most of the fragments are hollow hemispheres. It is trapped in the space of the hemispherical shape 19 and the locking jaw 20 by the locking jaw 20 in (19).

In addition, by bending the exit direction of the pulse gun and the outlet of the engine adapter 17 by 90 degrees with respect to each other, there is no damage to the engine combustion chamber wall as the debris is already greatly reduced when the debris flows into the engine. .

By designing the induction cavity 11 of the pressure induction part B to have a hemispherical shape 19 and a locking jaw 20 as shown in FIG. 3, damage by debris that may be applied to the combustion chamber wall can be minimized. .

Also, by installing two or more pulse gun adapters 13 with an inclination like the pulse gun pressure wave inlet 14, the pulse gun adapter 13 is directly connected to the high pressure / high temperature pressure wave of the pulse gun that is pre-exploded when a pressure wave is generated at a time interval. By preventing exposure, it serves to protect the pulse gun which will be exploded later.

The timing of artificial disturbance of the pulse gun is carried out at B ₁ and B ₂ in a graph indicating time (τ) on the x-axis and combustion chamber pressure (Pc) on the y-axis, as shown in FIG. In the initial ignition section, excessive overshoot of the combustion pressure occurs, and after a certain time, it reaches a steady state of the combustion pressure (Pc nom), and in general, the perturbation component of the combustion chamber pressure is dissipated by external disturbance. It is stable if the time taken to secure a stable state is within about 25 msec. Therefore, since the time difference Δτ between the two atoms B ₁ and B ₂ may be a value larger than this 25 msec, there may be a difference in the atomization time of 2 to 3 seconds as shown in FIG. 1. The total burning time is 10 seconds appears, but 10 seconds at 1 is an arbitrary value, initial detonator (B ₁₎ 5 seconds to again initial detonator (B ₁₎ the final detonator (B ₂₎ extent of up to 2 seconds to 3 seconds from to Detonation occurs at intervals of time, since the detonation is usually carried out when the combustion of the engine is stabilized, the pulse gun is exposed to high temperatures as the hot / high pressure combustion gas flows into the pressure wave induction device and the pulse gun. Depending on the nature of the initiator, misexplosion can occur.

In order to prevent such an explosion of the pulse gun, a nitrogen purging adapter 16 is installed in the pressure wave inducing apparatus, and the nitrogen is set to an atmospheric pressure higher than the combustion chamber pressure (about 2 to 5 atmospheres higher than the combustion chamber pressure) before purging the engine. By supplying in the direction of nitrogen 15, hot / high pressure gas from the engine is prevented from flowing into the pressure wave induction device and the pulse gun.

When the pulse gun is ignited at a given point in time, a pressure wave such as the pulse gun pressure wave trajectory 18 is applied to the engine because a pressure considerably higher than the pressure by nitrogen purging is applied to the pressure wave induction apparatus.

In the case of small engines, the pressure setting alone may cause a flow rate that interferes with normal operation, and may cause malfunctions such as dissipation or excessively hard start at the ignition moment or in the normal combustion section.

Therefore, in order to apply to the miniature engine, a small amount of purging system must be separately constructed as shown in FIG. 5. 5 is a schematic diagram of a purging system according to the present invention, which includes one or more reservoirs 510 for storing nitrogen among inert gases such as nitrogen, argon, and helium, a manual valve 520, and an automatic valve 530. ) And a main purging part including a check valve 570, and a sub purging part including an automatic valve 540, an orifice 550, and a check valve 560. Before the combustion test, the nitrogen of the reservoir 510 is supplied through the manual valve 520, wherein the pressure of the reservoir 510 is set to a pressure higher than the combustion pressure, for example, about 2 to 5 bar higher than the combustion pressure. A pressure gauge and a pressure transmitter may be provided between the reservoir 510 and the manual valve 520 to check whether the nitrogen gas is pressurized at an appropriate pressure. Nitrogen supplied through the manual valve 520 is supplied to the automatic valve 530 of the main purging part and the automatic valve 540 of the sub purging part, and these automatic valves 530 and 540 are externally controlled (not shown). When the engine is controlled by the controller to perform the opening and closing operation, and the engine is operated with a small thrust force (for example, a thrust of 1 ton or less), the sub purging part is operated first by the control of the control unit so that nitrogen is discharged by the automatic valve 540. Supplied. The nitrogen passing through the automatic valve 540 is controlled and supplied to a predetermined amount of nitrogen gas by the orifice 550 of the sub-purging part. For example, when the engine thrust is 100 kg, the diameter of the orifice is 1 mm and the nitrogen gas is supplied. 1t engine thrust is equipped with an orifice of 5mm diameter, when the combustion test is connected to a 550kg thrust engine as in the present invention is equipped with an orifice having a diameter of 2mm to 2.5mm to supply a predetermined nitrogen gas do. The reason for supplying with a predetermined amount of nitrogen gas is that in the initial ignition section, even a small amount of nitrogen can seriously affect the combustion of the combustion chamber. For example, even if the flame is stably formed, the shape of the flame may be distorted or unstable by the purged nitrogen (eg, the detonation flame is turned off by a predetermined amount of nitrogen). In order to prevent such serious effects, a predetermined amount of nitrogen gas is supplied through the sub purging portion. After a certain period of time and a stable combustion situation is secured, the main purging unit is operated by the control of the controller to supply more than a predetermined amount of nitrogen. Of course, combustion tests of large thrust engines (eg, two or more ton thrust engines) supply nitrogen only through the main purge without the need for a sub purge. Here, both the main purge part and the sub purge part are provided with check valves for preventing reverse flow of nitrogen, respectively.

The sub purging part has an orifice 550 and is connected to the pressure inducing part B to be applied to engines of various sizes.

Since the amount of propellant supplied to the combustion chamber is small until the main combustion, the sub-purging system using the orifice is operated to supply a small purge flow rate, preventing severe distortion of the combustion field even in a small scale engine, and the main combustion region Will act as the main fuzzing system.

If a high explosive such as RDX is in close contact with the pulse gun body, the impact is transmitted directly to the pulse gun body by the omnidirectional explosion force and the body may rupture.

Detonation in a state in which the air gap 25 is not completely in contact with the body may cause serious damage to the body, such as full / partial rupture.

This is because the explosive force of the assertive medicine (3) is omnidirectional, so that all the shock is transmitted to the outer wall of the body. A 1 mm air gap 25 as shown in FIG. 6 was introduced.

In general, damage is caused to the contact surfaces before and after the membrane 1 by the pressure waves generated by the detonation of the gunpowder and the high temperature flame.

In this case, the pulse gun adapter must be replaced every time due to damage, which is not only cumbersome in the operation of the experiment but also causes time / economical loss.

Therefore, it is preferable to operate the remaining portions except for the detonation unit (A) to be reusable.

In order to solve the problem of thermal damage of the contact surface before and after the membrane (1), by introducing a disposable outlet jaw insert (23) having an outlet extension on the outer contact surface of the membrane (1) by preventing the hot gas flow into the contact portion You can stop it.

In addition, in order to maintain the airtightness on the contact surface and to absorb the explosion impact amount, the O-ring 22 is installed to detonate, thereby solving the problem of good condition and airtightness.

The present invention provides a technique for manufacturing a pulse gun that can reliably provide artificial disturbance in order to evaluate the combustion stability of the rocket engine combustion, and to provide a reusable pressure wave induction device for effective experiments in actual engine combustion test.

By performing the SRT in the operation of the actual combustion chamber using the present invention, it is possible to reduce the trial and error associated with engine development, and to develop a stable engine.

The present invention can be applied to the purging system according to the thrust size and operating conditions of the engine, and at the same time to provide the effect that can be reused multiple times the joint device without a separate replacement only by replacing the detonator.

1 is a test operation graph of the present invention.

Figure 2 is a cross-sectional view of the installation state of the pulse gun of the present invention.

Figure 3 is a cross-sectional view of the pressure wave induction apparatus of the present invention.

Figure 4 is a top view of the pressure wave induction apparatus of the present invention.

5 is a block diagram of a purging system of the present invention.

Figure 6 is a detailed view of the detonator of the present invention.

Figure 7 is an exploded cross-sectional view of the pulse gun adapter and the detonator of the present invention.

[Description of Symbols for Main Parts of Drawing]

1: membrane 2: connecting nut

3: Claim 4: Electric supply unit

5: airtight part 6: fixing pin

7: electrical connector 8: pulse gun cavity

9: initiator 10: airtight part fixing part

11: guide cavity 12: main trajectory of membrane fragments

13: pulse gun adapter 14: pulse gun pressure wave inlet

15: nitrogen for purging 16: adapter for nitrogen purging

17 engine adapter 18 pulse gun pressure wave trajectory

19: induction cavity hemispherical shape 20: locking jaw 22: O-ring 25: air gap

23: exit jaw insert 24: detonation part

Claims (8)

A detonator provided with a pulse gun cavity in which an assertive drug and an initiator are installed and a membrane sealing one side of the pulse gun cavity; An electrical supply connected to the electrical supply and an electrical supply for igniting an initiator installed inside the initiator, opposite the membrane; An airtight part fixing part connecting the electrical connector and the detonating part and having a fixing pin positioned therein; A connection nut for connecting the initiator and the pulse gun adapter at the membrane side of the initiator; An outlet jaw insert having an extension mounted between the pulse gun adapter and the membrane; O-ring for airtightness and shock absorption between the pulse gun adapter and the detonator; Pulse gun operation for rocket engine combustion stability evaluation, characterized in that the nitrogen purging adapter connected to the nitrogen purging system and the engine adapter are installed on both sides and the pressure inducing part is installed on the opposite side of the pulse gun adapter. And reusable joint devices. A nitrogen purging system used in connection with a nitrogen purging adapter of a reusable induction joint device, A reservoir storing nitrogen; A manual valve for supplying nitrogen of the reservoir; A main purging part having an automatic valve and a check valve for sending nitrogen supplied from the manual valve; And A sub-purging portion having an orifice, one automatic valve, and a check valve for supplying any amount of nitrogen supplied from the manual valve, According to the thrust of the engine to which the induction cavity device is connected, purge with a predetermined nitrogen gas using the sub purging part below a predetermined engine thrust, and use the main purging part without the sub purging part above a predetermined engine thrust. Nitrogen purging system, characterized in that for purging. The method of claim 1, wherein an air gap is provided between the outside of the claim drug and the inside of the pulse gun body to prevent damage caused by the explosive force of the claim drug. Reusable induction cavity device. delete delete The method of claim 1, wherein the internal shape of the induction cavity has a hemisphere in the induction cavity and a locking jaw on the opposite side of the hemispherical shape, the operation of the pulse gun for the rocket engine combustion stability evaluation Joint device. According to claim 1, wherein the pulse gun adapter is a pulse gun operating and reusable induction joint device for rocket engine combustion stability evaluation, characterized in that at least two or more pulse gun pressure wave inlet is installed inclined toward the center of the pressure induction portion. . 2. The apparatus of claim 1, wherein the outlet of the engine adapter is angled 90 degrees with respect to the exit direction of the pulse gun.