JP2015071981A - Rocket engine burning test device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rocket engine burning test device capable of further ensuring afterburning measures at a time of purging unburned propellant.SOLUTION: Provided is a rocket engine burning test device 1. The rocket engine burning test device 1 includes an afterburning prevention mechanism 10 that includes a liquid supply source 11 supplying a liquid of an inert gas; a transfer pipe 12 connected to the liquid supply source 11 and transferring the inert gas supplied from the liquid supply source 11; and a purge pipe 13 connected to the transfer pipe 12 and arranged around an opening portion that serves as an exhaust side of a rocket engine. The transfer pipe 12 is configured to gasify the liquid during transfer while transferring the liquid of the inert gas. The purge pipe 13 is configured to inject the inert gas transferred by the transfer pipe 12 in a gaseous state.

Description

  The present invention relates to a rocket engine combustion test apparatus.

  In general, in a combustion test for a rocket engine, unburned propellant is discharged from the engine by purging at the end of the test or at the time of cutoff when the engine is turned off to stop combustion. And the unburned propellant discharged is ignited by the flame of the external torch, burned, and consumed, thereby preventing the unburned propellant from burning unexpectedly and ensuring the safety of the test.

By the way, when the unburned propellant discharged is ignited by the flame of the external torch and burned, so-called “afterburning” occurs in which the flame wraps around the engine. For this reason, the flame is prevented from being burned around by sufficiently taking disaster prevention measures.
In addition, as such a fire extinguisher for a rocket engine combustion test, a fire extinguisher that directly sprays liquid nitrogen in a liquid state is known (see, for example, Patent Document 1).

JP-A-4-116255

  However, when the above-mentioned “afterburn” occurs, a cable around the engine may be burnt even though the fire prevention measures are sufficiently taken. Therefore, since the cost of the combustion test becomes high due to damage or deterioration of the equipment, it is desired to provide a more reliable countermeasure for afterburning.

  In addition, the fire extinguishing device that sprays liquid nitrogen directly in liquid form is a fire extinguishing facility for unexpected fires, and it can be applied when purging unburned propellant as part of a combustion test. Can not. That is, the combustion of the unburned propellant by the purge is performed in order to consume the entire amount of the unburned propellant by combustion in order to prevent the unburned propellant from being accidentally burned. Therefore, if you spray liquid nitrogen directly into the flame when burning this unburned propellant, the flame will disappear before the entire amount of unburned propellant is consumed, and part of the unburned propellant will not be consumed. Will remain. As a result, the unburned propellant that remains without being consumed remains unresolved.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an engine combustion test apparatus for a rocket that can more reliably take measures against afterburning when purging of unburned propellant.

The rocket engine combustion test apparatus of the present invention is a rocket engine combustion test apparatus,
A liquid supply source for supplying an inert gas liquid, a transfer pipe connected to the liquid supply source for transferring an inert gas liquid supplied from the liquid supply source, and connected to the transfer pipe; A purge pipe disposed around an opening on the exhaust side of the rocket engine, and a post-combustion prevention mechanism,
The transfer pipe is configured to vaporize the liquid during the transfer while transferring the liquid of the inert gas, and the purge pipe jets the inert gas transferred by the transfer pipe in a gaseous state. It is configured.

  Further, in the rocket engine combustion test apparatus, the purge pipe is formed in a ring shape and injects an inert gas in a cylindrical shape in an extending direction on the opening side of the rocket engine. It is preferable to be configured.

  Further, in the rocket engine combustion test apparatus, the purge pipe is formed with a plurality of nozzles for injecting an inert gas in a gaseous state, and the nozzle of the purge pipe is the opening of the rocket engine. It is preferable that they are arranged so as to have a height equal to or higher than the height of the edge.

  Further, in the rocket engine combustion test apparatus, the purge pipe is disposed so that an edge of the opening of the rocket engine is positioned within an injection angle of an inert gas injected from the nozzle. Is preferred.

According to the rocket engine combustion test apparatus of the present invention, while the inert gas liquid is being transferred by the transfer pipe, the liquid is vaporized during the transfer, and the inert gas is injected in a gaseous state from the purge pipe. Therefore, a relatively small volume of inert gas liquid can be quickly transferred by transferring the liquid, and a relatively large volume of inert gas can be instantaneously injected by jetting in a gaseous state. Can do. Thereby, the facilities accompanying the transfer of the inert gas can be simplified, and the cost of the combustion test can be reduced.
In addition, since a relatively large volume of inert gas can be instantaneously injected, for example, when the discharged unburned propellant is burned by injecting the gas of the inert gas into a cylindrical shape, the flame wraps the engine. “Afterburning” can be reliably prevented. Therefore, it is possible to more reliably take measures against afterburning when unburned propellant is purged.

1 is a schematic configuration diagram of an embodiment of a rocket engine combustion test apparatus of the present invention. It is a schematic diagram for demonstrating the afterburn prevention mechanism with which the engine combustion test apparatus for rockets shown in FIG. 1 is equipped. It is a principal part enlarged view for demonstrating the structure of purge piping and its nozzle.

The rocket engine combustion test apparatus of the present invention will be described in detail below.
FIG. 1 is a diagram showing a schematic configuration of an embodiment of a rocket engine combustion test apparatus according to the present invention. FIG. 2 is a diagram for explaining a post-combustion prevention mechanism provided in the rocket engine combustion test apparatus shown in FIG. FIG.

  In FIG. 1, reference numeral 1 is a rocket engine combustion test apparatus, and 2 is a rocket engine subjected to a combustion test by the combustion test apparatus 1. The rocket engine 2 includes a combustion chamber 3 and a nozzle extension (not shown) connected to the combustion chamber 3. However, in this embodiment, as the rocket engine 2, the combustion test is performed in a state where the nozzle extension is removed, that is, only the combustion chamber 3.

  The combustion chamber 3 is connected to an injection (not shown) and burns a propellant composed of a fuel and an oxidant supplied from the injection. The combustion chamber 3 is formed in a cylindrical shape on the downstream side, that is, on the side opposite to the injection, and its side surface is gradually reduced in diameter and then gradually expanded, thereby allowing the combustion gas to expand. .

  The rocket engine combustion test apparatus 1 holds the rocket engine 2 (combustion chamber 3) so that the downstream (downward) opening of the combustion chamber 3 is at a predetermined distance from the floor surface 4. Is lifting. The rocket engine combustion test apparatus 1 is configured to supply a propellant to the combustion chamber 3. When supplying the propellant, the rocket engine combustion test apparatus 1 adjusts the mixing ratio of the fuel and oxidant in the propellant to an appropriate ratio set for the test, for example, or supplies the propellant supply pressure, The combustion pressure can be adjusted to a preset pressure. The rocket engine combustion test apparatus 1 is provided with various measuring devices so that the combustion state can be observed and various data can be obtained.

  A plurality of external torches 6 are arranged on the floor surface 4 on the combustion gas exhaust side of the rocket engine 2, that is, below the opening 5 of the combustion chamber 3. These external torches 6 continue to form a flame by combustion during the combustion test of the rocket engine 2 and further when the unburned propellant is purged at the time of cut-off described later. As a result, these external torches 6 are ignited by the propellant discharged without being burned from the rocket engine 2 unexpectedly or by purge, and burned. That is, the unburned propellant stays as it is without being consumed, and is prevented from unexpectedly burning.

  In addition, the rocket engine combustion test apparatus 1 includes a post-combustion prevention mechanism 10. As shown in FIG. 2, the afterburning prevention mechanism 10 includes a liquid supply source 11 that supplies a liquid of nitrogen that is an inert gas, and liquid nitrogen that is connected to the liquid supply source 11 and supplied from the liquid supply source 11. A transfer pipe 12 to be transferred and a purge pipe 13 connected to the transfer pipe 12 are provided.

The liquid supply source 11 is provided in a cryoevaporator line 30 provided in a factory, a laboratory, or the like. The liquid supply source 11 stores liquid nitrogen (LN ₂ ) and vaporizes it through a pipe 31 in the line. Nitrogen (GN ₂ ) is supplied to a desired location. That is, the pipe 31 is provided with the evaporator 32, liquid nitrogen by therethrough (LN ₂₎ is vaporized, and is transported with the nitrogen gas (GN _2).

  On the other hand, the transfer pipe 12 constituting the afterburning prevention mechanism 10 does not include an evaporator in the present embodiment, and transfers the liquid nitrogen while vaporizing the liquid nitrogen by receiving heat or the like during the transfer. It is configured. When the transfer pipe 12 is supplied to the purge pipe 13, almost the entire amount of liquid nitrogen is vaporized. That is, the length, inner diameter, and the like of the transfer pipe 12 are set corresponding to the amount of nitrogen supplied to the purge pipe 13, so that almost the entire amount of liquid nitrogen is vaporized during the transfer.

  In the transfer pipe 12, a plurality of on-off valves 33 are provided in the cryoevaporator line 30, and a pressure reducing valve 14 is provided outside the cryoevaporator line 30. Thereby, the transfer pipe 12 is divided into the high pressure equipment side and the test equipment side on the upstream side and the downstream side of the pressure reducing valve 14. The transfer pipe 12 is provided with a pressure sensor 15 and a temperature sensor 16 on the downstream side of the pressure reducing valve 14. As a result, the pressure and temperature of nitrogen flowing in the transfer pipe 12 are continuously detected during operation.

  A flexible pipe 17 is provided on the downstream side of the pressure reducing valve 14. Thereby, even if the pressure in the transfer pipe 12 suddenly changes due to the rapid change from liquid nitrogen to nitrogen gas or the injection of nitrogen gas from the purge pipe 13, the flexible pipe 17 expands and contracts, This sudden change is absorbed. For example, when the length of the transfer pipe 12 cannot be sufficiently secured and it is difficult to vaporize almost the entire amount of liquid nitrogen by receiving heat during transfer, the downstream side of the pressure reducing valve 14 in the transfer pipe 12 A heater or an evaporator may be provided to facilitate the vaporization of liquid nitrogen.

  In this embodiment, the purge pipe 13 is formed in a ring shape (annular shape) surrounding the opening 5 of the combustion chamber 3 of the rocket engine 2 shown in FIG. The purge pipe 13 is provided with a plurality of nozzles 18 along its circumferential direction as shown in FIG. These nozzles 18 are formed by holes formed downward and obliquely (inward) as shown in FIG. 3, and are arranged at equal intervals along the circumferential direction of the purge pipe 13. For example, 26 holes (nozzles 18) having an inner diameter of 3 mm are formed in the purge pipe 13 at a pitch of about 15 °.

Further, as shown in FIG. 1, the purge pipe 13 is disposed horizontally surrounding the opening 5 of the combustion chamber 3 of the rocket engine 2. As shown in FIG. 3, the nozzle 18 of the purge pipe 13 is arranged so that its height is equal to or higher than the height of the edge 5 a of the opening 5 of the combustion chamber 3. Under such a configuration, by injecting nitrogen (GN ₂ ) downward and obliquely (inward) from the nozzle 18, the purge pipe 13 extends in the direction of extension on the opening 5 side of the combustion chamber 3 (see FIG. (Indicated by a two-dot chain line in FIG. 3), nitrogen (GN ₂ ) is jetted in a cylindrical shape.

Further, as the angle at which the nozzle 18 is inclined (inward), that is, the inclination angle θ that is inclined with respect to the vertical line, the injection angle of nitrogen (GN ₂ ) in the range indicated by the arrow in FIG. Assuming that the spread angles are 45 ° each, the edge 5a of the opening 5 of the combustion chamber 3 is set within the injection angle, that is, within the injection range. For example, the inclination angle θ is about 10 °. With this configuration, between the injection range of the edge 5a and nitrogen of the opening portion 5 of the combustion chamber 3 (GN _2), so that a gap is not formed.

Next, a test method using the rocket engine combustion test apparatus 1 having such a configuration will be described.
First, as shown in FIG. 1, the combustion chamber 3 of the rocket engine 2 to be tested is set in the rocket engine combustion test apparatus 1 and is floated from the floor 4 by a predetermined distance (for example, 50 cm to 100 cm). Hang it on. At this time, the purge pipe 13 is adjusted so that the nozzle 18 is arranged as shown in FIG.
Then, after a flame is blown out from the external torch 6, a predetermined combustion test is performed.

When the combustion test is completed or interrupted in this way, the unburned propellant is discharged from the opening 5 of the combustion chamber 3 by purging in the same manner as in the prior art at the time of cutoff. At that time, simultaneously with or prior to the discharge of the unburned propellant, the afterburning prevention mechanism 10 is operated, the on-off valve 33 is opened, and liquid nitrogen (LN ₂ ) is supplied from the liquid supply source 11 to the transfer pipe 12. For example, liquid nitrogen (LN ₂ ) is supplied to the transfer pipe 12 at a flow rate of about 0.04 kg / s to 0.05 kg / s.

Liquid nitrogen (LN ₂ ) supplied to the transfer pipe 12 receives heat from outside air or the like through the transfer pipe 12 while flowing through the transfer pipe 12. Then, the gas passes through the pressure-reducing valve 14 and is transferred from the high-pressure facility side set to a high pressure to the test facility side set to a relatively low pressure, thereby gradually evaporating and flowing the gas in the flowing nitrogen (GN Increase the amount of ₂ ).

When reaching the purge pipe 13, the entire amount is vaporized to become nitrogen gas (GN ₂ ) and is injected as it is from the nozzle 18. In addition, even if a part of the nitrogen transferred to the purge pipe 13 is liquid, there is a high possibility that the nitrogen will be vaporized by being decompressed when jetted from the nozzle 18. Therefore, the transfer pipe 12 may be configured to transfer the liquid nitrogen (LN ₂ ) to the purge pipe 13 while slightly containing liquid without necessarily vaporizing the entire amount of liquid nitrogen (LN ₂ ) during the transfer. Furthermore, liquid nitrogen (LN ₂ ) may be slightly contained in the nitrogen gas (GN ₂ ) ejected from the nozzle 18. Even if a part of the nitrogen sprayed from the nozzle 18 is liquid nitrogen (LN ₂ ), this liquid nitrogen (LN ₂ ) is instantly vaporized by a flame formed by the combustion of unburned propellant described later. This is because it does not act to extinguish this flame instantaneously.

When nitrogen gas (GN ₂₎ is injected from the way the nozzle 18, the nozzle 18 as described above is disposed at a height above the height of the edge 5a of the opening 5 of the combustion chamber 3 Thus, nitrogen gas (GN ₂ ) is injected in a cylindrical shape in the extending direction on the opening 5 side of the combustion chamber 3. Further, a gap is not formed between the nitrogen gas injected in this way and the edge 5 a of the opening 5 of the combustion chamber 3.

It should be noted that the external torch 6 has a strong combustion force, so even if it receives nitrogen gas (GN ₂ ) injected from the nozzle 18, it spreads when the nitrogen gas (GN ₂ ) itself reaches the external torch 6 side. Since the flow velocity is low, the flame is not blown out.

Under these conditions, when unburned propellant is discharged from the opening 5 of the combustion chamber 3 by purging, nitrogen gas (GN ₂ ) 19 is shown by a two-dot chain line in FIG. 1 as shown in FIG. Since it is injected in a cylindrical shape along the extending direction 20 on the opening 5 side of the combustion chamber 3, the discharged unburned propellant is confined in the nitrogen gas 19. Then, it is ignited by the flame of the external torch 6 and burns to form a flame 21.

However, the flame 21 thus formed is also trapped in the nitrogen gas 19 because the unburned propellant discharged from the combustion chamber 3 is still trapped in the nitrogen gas 19. Maintained in a state.
Since the discharge of the unburned propellant by such a purge is completed in about 1 minute, for example, the injection of nitrogen from the purge pipe 13 is performed for 1 minute or more, for example, about 2 minutes.

Note that when unburned propellant is discharged by such a purge, the operator visually observes the state of the flame 21, confirms that the flame 21 has completely disappeared, and then stops after-burning so as to stop nitrogen injection. The prevention mechanism 10 is controlled.
At this time, in the present invention, nitrogen gas (GN ₂ ) is injected from the purge pipe 13, so that the water vapor in the atmosphere is cooled and condensed as when liquid nitrogen (LN ₂ ) is injected, and the white smoke Is not generated. Therefore, the flame 21 in the nitrogen gas 19 can be observed with good visual observation.

According to such a rocket engine combustion test apparatus 1, liquid nitrogen (LN ₂ ) is transferred by the transfer pipe 12, liquid nitrogen is vaporized during the transfer, and nitrogen gas (GN ₂ ) is injected from the purge pipe 13. As a result, a relatively small volume of liquid nitrogen can be quickly transferred by transferring the liquid, and a relatively large volume of nitrogen gas (GN ₂ ) can be instantaneously injected by injecting it in a gaseous state. Can be injected. Thereby, the facility accompanying the transfer of nitrogen can be simplified, and the cost of the combustion test can be reduced.

In addition, since a relatively large volume of nitrogen gas (GN ₂ ) can be instantaneously injected, by injecting the nitrogen gas (GN ₂ ) into a cylindrical shape, the discharged unburned propellant flame 21 wraps around the engine. “Afterburning” can be reliably prevented. Therefore, it is possible to more reliably take measures against afterburning when unburned propellant is purged.

Further, since the purge pipe 13 is disposed so that the edge 5a of the opening 5 of the combustion chamber 3 is located within the injection angle of the nitrogen gas injected from the nozzle 18, the end of the opening 5 of the combustion chamber 3 is located. A gap is not formed between the edge 5 a and the nitrogen (GN ₂ ) injection range, that is, the nitrogen gas 19. Therefore, it is possible to reliably prevent the unburned propellant flame 21 from leaking through such a gap and causing “afterburning” that envelops the engine.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.
For example, in the above-described embodiment, the liquid supply source 11 provided in a cryoevaporator line 30 provided in a factory, a laboratory, or the like is used. However, if the tank stores liquid nitrogen, the cryoevaporator is used. It is also possible to use an independently provided one instead of the one provided at 30.

In the above embodiment, nitrogen is used as the inert gas, but an inert gas such as helium (He) or argon (Ar) may be used instead.
Further, in this embodiment, the rocket engine 2 as a test object is only in the combustion chamber 3 with the nozzle extension removed, but depending on the type of combustion test, the nozzle extension is attached to the combustion chamber 3. It is good also as a to-be-tested body. In that case, the afterburning prevention mechanism is configured so that the purge pipe is arranged around the opening of the nozzle extension.

DESCRIPTION OF SYMBOLS 1 ... Rocket engine combustion test apparatus, 2 ... Rocket engine, 3 ... Combustion chamber, 5 ... Opening, 5a ... Edge, 6 ... External torch, 10 ... Afterburning prevention mechanism, 11 ... Liquid supply source, 12 ... Transfer pipe, 13 ... purge pipe, 18 ... nozzle, 19 ... nitrogen gas, 21 ... flame

Claims (4)

A rocket engine combustion test device,
A liquid supply source for supplying an inert gas liquid, a transfer pipe connected to the liquid supply source for transferring an inert gas liquid supplied from the liquid supply source, and connected to the transfer pipe; A purge pipe disposed around an opening on the exhaust side of the rocket engine, and a post-combustion prevention mechanism,
The transfer pipe is configured to vaporize the liquid during the transfer while transferring the liquid of the inert gas, and the purge pipe jets the inert gas transferred by the transfer pipe in a gaseous state. An engine combustion test apparatus for a rocket characterized by comprising.   The purge pipe is formed in a ring shape and configured to inject a gas of an inert gas in a cylindrical shape in an extending direction on the opening side of the rocket engine. The engine combustion test apparatus for rockets according to 1. The purge pipe is formed with a plurality of nozzles for injecting an inert gas in a gaseous state,
The rocket engine combustion test apparatus according to claim 2, wherein the purge pipe is arranged such that the nozzle has a height equal to or higher than a height of an edge of the opening of the rocket engine. .   The rocket engine according to claim 3, wherein the purge pipe is arranged so that an edge of the opening of the rocket engine is positioned within an injection angle of an inert gas injected from the nozzle. Engine combustion test equipment.

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