CN113090393B

CN113090393B - Device capable of igniting for multiple times based on solid energetic material

Info

Publication number: CN113090393B
Application number: CN202110373023.7A
Authority: CN
Inventors: 马虎; 姚新禹; 严宇; 胡洪波
Original assignee: Nanjing University of Science and Technology
Current assignee: Nanjing University of Science and Technology
Priority date: 2021-04-07
Filing date: 2021-04-07
Publication date: 2022-04-19
Anticipated expiration: 2041-04-07
Also published as: CN113090393A

Abstract

The invention discloses a device capable of igniting for multiple times based on a solid energetic material, which can be used for multiple ignition of various aerospace engines such as a detonation engine and a ramjet engine. Solid charge is filled in the ignition tube, the ignition of the excited charge is controlled, the ignited high-temperature and high-pressure flame is quickly transmitted into a combustion chamber of the engine through the flame transmission tube to realize ignition, and the ignition energy is far greater than the energy generated by spark discharge, so that the ignition requirement under certain limit conditions can be met, for example, the direct detonation of the detonation wave of the rotary detonation engine. Meanwhile, in order to realize multiple ignitions, a plurality of ignition tubes are connected in parallel, a rotary valve-like mechanism is utilized to rotate a preset angle of an ignition tube box, and the ignition tube which is not ignited is switched to a position communicated with a flame transfer tube, so that the next ignition can be realized, wherein the ignition frequency depends on the number of the ignition tubes connected in parallel.

Description

Device capable of igniting for multiple times based on solid energetic material

Technical Field

The invention belongs to the field of ignition devices of aerospace engines, and particularly relates to a device capable of igniting for multiple times based on a solid energetic material.

Background

For aerospace engines such as detonation engines and the like, extremely large ignition energy is needed to realize normal combustion of combustion, such as direct detonation of detonation waves, but ignition energy provided by an electric spark plug is far insufficient, so engineering application generally uses a long detonation tube to realize DDT (detonation-to-detonation process) in the prior art. For a rotary detonation engine, a combustion chamber is annular, a conventional solution is to use a pre-detonation tube, install a long and thin pre-detonation tube on the side of the combustion chamber, and fill the pre-detonation tube with premixed gas of hydrogen and oxygen. However, this method has many problems, the first is that the general length of the pre-detonation tube is above 0.5 m, if it is too short, the DDT can not be completed to form detonation wave, which increases the whole size of the engine, and in addition, if the engine is not using oxyhydrogen mixture as fuel, another set of hydrogen and oxygen storage and delivery system is needed, which greatly increases the mass size and complexity of the system, and the more complex the system, the more the probability of relative problems is. Secondly, the process of filling the pre-mixing gas into the pre-detonation tube can be automated through an electric control valve, but the replacement of a sealing cover between the pre-detonation tube and the combustion chamber is difficult to leave manual operation, and the sealing performance of an interface is difficult to ensure due to simple mechanical rotation replacement, so that the detonation waves leak from the interface easily and the combustion chamber cannot be ignited. This means that the method is disposable and difficult to re-fire if the aerospace vehicle is extinguished in flight. Therefore, the ignition device which has simple structure, small volume and high reliability and can be used repeatedly becomes a necessary condition for various novel aerospace engines from laboratories to engineering application.

Disclosure of Invention

The invention aims to provide a device capable of igniting for multiple times based on a solid energetic material so as to realize the multiple ignition function of some aerospace engines

The technical solution for realizing the purpose of the invention is as follows:

a device capable of igniting for multiple times based on solid energetic materials comprises a combustion chamber, a flame transfer pipe, an ignition pipe box, a rear cover plate, a central shaft, a charge and a front cover plate;

the ignition tube box is arranged between the rear cover plate and the front cover plate and can rotate relative to the two cover plates; one end of the central shaft penetrates through the rear cover plate and is fixedly connected with the ignition tube box, and the other end of the central shaft is connected with a rotation driving device for driving the ignition tube box to rotate; a plurality of ignition tubes are arranged in the ignition tube box in an annular and equally-spaced parallel manner, the axial direction of the ignition tubes is parallel to the axial direction of the flame transfer tube, and heat insulation materials are arranged between the ignition tubes; the front cover plate is provided with a flame transfer hole, one end of the flame transfer pipe is connected with the flame transfer hole, and the other end of the flame transfer pipe is connected with the combustion chamber; the outer side of the front cover plate is provided with a heat insulating material, and the outer side of the ignition tube is provided with a sealing cover; the ignition tubes are internally provided with sealed explosive charges, and the tail end of each ignition tube is provided with a detonating device for igniting the explosive charges; when the ignition device works, the ignition tube box rotates to align one ignition tube with the fire transfer hole, and the ignition device ignites the charge to finish the ignition of the fuel in the combustion chamber.

Compared with the prior art, the invention has the following remarkable advantages:

repeated ignition of the detonation engine can be realized, and even under the working condition of flying of the aircraft, the engine can still realize re-ignition after flameout; the length of the original detonation engine igniter can reach 50-100cm, and the detonation engine igniter can be reduced to about 10 cm.

The ignition energy generated by solid charge explosion is enough to realize direct detonation of detonation waves, and the whole size of the engine is reduced without a long pipe in a DDT process, so that the engine has one less long pipe of 50-100cm and becomes a standard cylinder, and in addition, the ignition is realized for many times by using a simple mechanical rotary valve, and the engine is safe and reliable. In addition to rotary detonation engines, other engines requiring high ignition energy may also use the present invention.

Drawings

Fig. 1 is a plan view of a solid energetic material based multiple ignition device.

Fig. 2 is a three-dimensional cross-sectional view of a solid energetic material based multiple ignition device.

Fig. 3 is a partial structure diagram of the ignition tube box, the ignition tube, the flame transfer tube and the central shaft.

FIG. 4 is a partial structure view of the flame tube and the front cover plate.

Fig. 5 is a partial structural view of the rear cover.

Detailed Description

The invention is further described with reference to the following figures and embodiments.

Fig. 1 is a plan view of a device for multiple ignitable based on solid energetic materials of the present invention, and fig. 2 is a three-dimensional sectional view, which comprises a combustion chamber 1, a flame transfer tube 2, an ignition tube 3, an ignition tube box 4, a rear cover plate 5, a central shaft 6, a charge 7, and a front cover plate 8.

With reference to fig. 1 to 5, the ignition tube box 4 is disposed between the rear cover plate 5 and the front cover plate 8, and can rotate relative to the two cover plates, and the three form a rotary valve; one end of the central shaft 6 penetrates through the rear cover plate 5 and is fixedly connected with the ignition tube box 4, and the other end of the central shaft 6 is connected with a rotary driving device for driving the ignition tube box 4 to rotate; a plurality of ignition tubes 3 are arranged in the ignition tube box 4, the ignition tubes 3 are annularly arranged in parallel at equal intervals, the axial direction of the ignition tube 3 is parallel to the axial direction of the flame transfer tube 2, and a heat insulating material is arranged between the ignition tubes 3; the front cover plate 8 is provided with a flame transfer hole 81, one end of the flame transfer pipe is connected with the flame transfer hole 81, and the other end of the flame transfer pipe is connected with the combustion chamber 1; the outer side of the front cover plate 8 is provided with a heat insulating material; a sealed explosive charge 7 is arranged in the ignition tube 3, a plastic sealing cover 31 is arranged outside the opening of the ignition tube 3, and the tail end of each ignition tube 3 is provided with a detonating device for igniting the explosive charge 7; in operation, the squib holder 4 is rotated to align one of the squibs 3 with the ignition hole 81, and the igniter ignites the charge 7 to complete ignition of the fuel in the combustion chamber 1.

In order to solve the above problems with the conventional methods, the present invention proposes a solution for ignition using a solid fuel. Black powder or other similar solid fuel is filled into the ignition tube 3, the ignition tube 3 to be ignited is aligned with the flame transfer tube 2, and the flame transfer tube 2 is communicated with the engine combustion chamber 1. The length of the whole ignition tube 3 is only a few centimeters at the shortest, and is far shorter than that of the pre-detonation tube, so that the overall size and weight of the aerospace engine are greatly reduced. In addition, the ignition energy requirement can be controlled by the igniters 3 with different pipe diameters or different charges. The charge 7 in the ignition tube 3 is ignited by an electric spark plug or a firing pin, high-temperature and high-pressure flame and shock wave generated by explosion of the charge 7 can easily burst the plastic sealing cover 31 and are transmitted into the combustion chamber 1 of the engine, the released energy is far larger than the energy directly released by a common electric spark plug, and for a detonation engine, the ignition energy generated by the igniter is enough to support direct initiation of the shock wave.

In order to realize multiple ignition, a plurality of ignition tubes 3 can be connected in parallel in an annular mode to form an ignition tube box 4, after the first ignition is finished, the position of the ignition tube 3 is kept unchanged, the ignited ignition tube 3 is right opposite to the engine combustion chamber 1, other ignition tubes are not communicated with the engine combustion chamber 1 and are blocked by a front cover plate 8, and therefore high-temperature and high-pressure gas does not enter the ignition tube 3 which is not ignited and charges in the ignition tube. When the ignition is needed again, the power device drives the ignition tube box 4 to integrally rotate for a preset certain angle, the ignition tube 3 of the unignited charge 7 is rotated to be aligned with the flame transmission tube 2, the to-be-ignited tube 3, the flame transmission tube 2 and the combustion chamber 1 are communicated, the mode of preparing to ignite the to-be-ignited charge 7 is started again, and the engine can be ignited to work again. Six to eight igniters 3 can be connected in parallel, so that the overall size is not overlarge, and sufficient ignition times can be guaranteed.

However, the problem exists that the charge is formed by mixing combustible materials and oxidant, and is easy to be accidentally ignited, and once the situation of high temperature and high pressure or physical impact occurs, the charge is easy to self-ignite and self-explode to cause danger.

The ignition box 4 is integrally a cylinder and is also a rotary valve, the top of the ignition box is provided with a front cover plate 8 which is tightly attached to the top surface of the ignition box 4, and the cover plate is provided with a through hole with the same diameter as that of the ignition pipe and is connected into a combustion chamber of an engine through a short pipe. Before ignition, the ignition tube to be ignited needs to be accurately aligned with the fire transfer hole 81 on the front cover plate 8, so that the explosion capability of the ignition tube can be smoothly transferred into the engine combustion chamber 1 without energy loss. In addition, the front cover plate 8 must be in close contact with the ignition box 4, and if a gap exists, the gap may cause leakage of high-temperature and high-pressure gas, whether generated when the ignition tube is ignited or generated in a combustion chamber of an engine in operation. If the high-temperature and high-pressure gas generated by the ignition tube 3 leaks, a part of ignition energy can be lost, and more seriously, if the high-temperature and high-pressure gas in the combustion chamber is transferred from the gap of the cover plate to the unignited ignition tube 3 in the working process of the engine, serious harm can be caused, the engine can continuously work for hours in practical application and the tightness of the front cover plate 8 and the ignition box 4 is continuously tested by the high-temperature and high-pressure combustion generated by the working of the engine unlike the explosion of only one moment in the ignition explosion.

The mass transfer and the heat transfer are transmitted from the engine combustion chamber 1, the engine releases a large amount of heat during working, the surface temperature of the outer wall of the engine combustion chamber is extremely high and can reach about 1000K generally, an igniter is arranged on the wall surface of the engine combustion chamber, the engine is roasted at high temperature all the time during long-time working, and once the charge reaches the minimum temperature required by combustion, the spontaneous explosion is very likely to occur. Therefore, the igniter must be insulated by a certain safety distance from the wall surface of the combustion chamber of the engine, and since a large amount of heat is transferred to the ignition tube 3 through the metal wall surface having good thermal conductivity by directly contacting the metal wall surface of the combustion chamber of the engine, the flame transfer tube 2 having a suitable length is required to separate the igniter from the wall surface of the combustion chamber 1. But not too long, which could lead to energy losses during the transfer of ignition energy and increase the overall size. In addition, the igniter needs to be wrapped entirely by a large amount of heat insulating material, especially the front end of the igniter, which is opposite to the combustion chamber of the engine, meaning that the maximum amount of heat is received. During operation, the ignited ignition tube 3 is directly communicated with the combustion chamber, and in the operation process, high-temperature and high-pressure fuel gas is filled in the ignition tube 3, so that heat can be transferred from the ignition tube to the adjacent ignition tube 3 to cause self-ignition and self-explosion, and therefore heat insulation materials are required to be filled between the ignition tubes in the ignition box.

As for the filling mode of the powder charge, the simple and traditional mode is that the ignition tube box 4 is a whole, a circle of ignition tube 3 is cut on the ignition tube box 4 in an annular mode, the tail end of the ignition tube 3 is sealed and provided with an electric spark plug, the powder charge 7 is filled at the tail end of the ignition tube 3, the electric spark plug releases energy to ignite the powder charge 7 during ignition, and the explosion wave breaks through the plastic sealing cover 31. This is structurally simple, but it is also quite time-consuming to fill a new charge 7 each time, since most of the solid charge is injected into the pipe in the pasty state and waits for it to solidify, if in the engineering practice the aircraft has just landed and has run out of all the ignition charges, but suddenly and temporarily has a flight mission, it is not too time to fill a new charge.

And a novel filling method is adopted, the powder charge is filled into an independent ignition tube 3 in advance and stored, and when the powder charge needs to be used, the ignition tube 3 is filled into an ignition tube box 4, so that the requirement of quick maneuvering reaction is met. Besides, the charging mode can be used for igniting by using an electric spark plug, the charging can be ignited by adopting a mode that a firing pin impacts a bullet tail, and in addition, the impact of explosion on the igniter during ignition can be reduced due to the protection of the tube shell of the ignition tube 3.

Claims

1. A device capable of igniting for many times based on solid energetic materials is characterized by comprising a combustion chamber, a flame transfer pipe, an ignition pipe box, a rear cover plate, a central shaft, a charge and a front cover plate;

the ignition tube box is arranged between the rear cover plate and the front cover plate and can rotate relative to the two cover plates; one end of the central shaft penetrates through the rear cover plate and is fixedly connected with the ignition tube box, and the other end of the central shaft is connected with a rotation driving device for driving the ignition tube box to rotate; a plurality of ignition tubes are arranged in the ignition tube box in an annular and equally-spaced parallel manner, the axial direction of the ignition tubes is parallel to the axial direction of the flame transfer tube, and heat insulation materials are arranged between the ignition tubes; the front cover plate is provided with a flame transfer hole, one end of the flame transfer pipe is connected with the flame transfer hole, and the other end of the flame transfer pipe is connected with the combustion chamber; the outer side of the front cover plate is provided with a heat insulating material, and the outer side of the ignition tube is provided with a sealing cover; the ignition tubes are internally provided with sealed explosive charges, and the tail end of each ignition tube is provided with a detonating device for igniting the explosive charges; when the ignition device works, the ignition tube box rotates, one ignition tube is aligned to the fire transfer hole, and the ignition device ignites the charge to finish the ignition of the fuel in the combustion chamber;

the ignition device is an electric spark plug or a firing pin, the electric spark plug is arranged in the ignition tube, and the firing pin is arranged in the ignition tube box and is opposite to the tail end of the ignition tube;

the ignition tube and the ignition tube box are of an integrated structure or a split structure, and when the ignition tube and the ignition tube box are of the integrated structure, a plurality of ignition tubes are processed in the ignition tube box; when the structure is split, a plurality of ignition tubes are arranged in the mounting hole of the ignition tube box.