RU2765672C1 - Method for forcing a dual-flow ejector pulse jet engine and forced dual-flow ejector pulse jet engine - Google Patents

Abstract

FIELD: engine building.

SUBSTANCE: group of inventions relates to equipment, primarily military, namely, to engines of aerial vehicles, and can be used, most likely, in engines of small unmanned aerial vehicles, such as surface-to-air, aviation, and tactical missiles, unmanned reconnaissance aircrafts, flying targets, etc. Forcing of a dual-flow ejector pulse jet engine (DFEPJE) consists in accelerating the combustion process by implementing the mechanism of oxidative methane pyrolysis forming acetylene. In order to implement the described process, coolable plates are installed in the second intake mixer pipe of the DFEPJE, and a coolable channel is installed in the back wall of the combustion chamber. Upon completion of the working cycle, burning gases containing methane, being cooled on the coolable plates and walls of the coolable channel, form acetylene further entering the combustion chamber at the suction cycle and causing acceleration of burning and growth of jet thrust.

EFFECT: claimed group of inventions allows for an increase in the jet thrust of the DFEPJE in the range of 15 to 20%.

2 cl, 5 dwg

Description

The invention relates to technology, primarily military, namely to aircraft engines, and can most likely be used in the engines of small unmanned aerial vehicles, such as, for example, unmanned reconnaissance aircraft, flying targets.

Known pulsating jet engine (hereinafter PuVRD) of the German cruise missile of the Second World War V-1 (see G.B. Sinyarev, M.V. Dobrovolsky. Liquid rocket engines. - Oborongiz, 1957, p. 19, 20) .

The well-known PuVRD is a pipe with a valve lattice, which consists of bearing elements - transverse rods, movable elements - flat elastic plates of constant thickness, attached to the side faces of the rods in pairs parallel to each other at a distance equal to the thickness of the rod, and support spacers placed in the middle between the pairs plates parallel to them. Each pair has a back-facing blind gap between the plates. Plates and spacers form longitudinal channels for the passage of air.

The flow on the PUVRD passes through the air intake and the valve grill into the combustion chamber. Easily evaporating fuel is also supplied there, after which the air-fuel mixture is ignited by a spark of an electric igniter. The combustion products rapidly expanding in all directions, falling into the dead gap between the plates, are slowed down, as a result of which the pressure increases there. This causes the plates to bend to the sides until they come into contact with the support spacers or side walls. The air channels of the valve grill are blocked. The combustion products flow through the nozzle into the atmosphere, and their pressure on the closed valve grill creates a thrust impulse of the PUVRD.

After the pressure drop, the valve lattice plates, under the action of their elasticity, as well as the rarefaction created in the chamber by the inertia of the outflowing gases, return to their original position. The next portion of air enters the chamber and the cycle repeats.

The main advantage of this type of PUVRD, based on the use of mechanical valve grids, is the high hydraulic resistance to combustion products trying to break through against the oncoming flow during an explosion in the combustion chamber.

Their drawback is the high hydraulic resistance when blowing the combustion chamber, especially at low flight speeds, which leads to a low cyclic volumetric filling and, as a result, to low specific and frontal thrust. But the main thing is that they give a drop in thrust at high flight speeds due to the mechanical bending of the valve petals by the dynamic air pressure, which leads to the transition to the ramjet mode.

The PuVRD is also known with the help of aerodynamic valves, which are often used as simple tubes, "Unsteady Flame Propagation", ed. J. G. Markstein, M., MIR, 1968, p. 401-407. In addition, PuVRD, in which mechanical valves are replaced with aerodynamic ones, are described in US patents No. 2796735, 1957; No. 2796734, 1957; No. 2746529, 1956; No. 2822037, 1958; 2812635, 1957; 3093962, 1963.

The disadvantages of this method of purging the PUVRD include the low amplitude of pressure pulsations in the combustion chamber and, accordingly, the low thermodynamic efficiency (efficiency) due to the low combustion rate of the air-fuel mixture.

A device is known for a forced bypass ejector pulsating jet engine protected by a patent for the invention RU 2717479, SEC F02K 7/067 (2020.01), published on 03/23/2020, BI No. 9. The forced dual-circuit ejector pulsating air-jet engine (DEPuVRD) contains, in particular, a combustion chamber, an inlet system of the first and second mixer pipes, aerodynamic valves, a fuel manifold and a fuel supply nozzle, a fuel heating coil and a resonator tube with a partial diffuser opening. A distinctive feature of this DEPuVRD is that the rear wall of the combustion chamber is made with the first echelon visor with rectangular slots for the formation of flat jet flows behind them, a perforated niche is made inside the combustion chamber behind the first visor with a second visor protruding into the flow, and the fuel heating coil has an uneven along the diameter and oblique along the axis of the winding.

As the closest analogue (prototype), the device of a forced bypass ejector pulsating air-jet engine (DEPuVRD), protected by a patent for invention RU 2714463 SPK F02K 7/067 (2019.08), published on February 17, 2020, BI No. 5, which contains, in particular, , a combustion chamber, an intake system of the first and second mixing pipes, aerodynamic valves, a fuel manifold and a fuel supply nozzle. An annular shell with a length of 0.3-0.5 caliber of the second mixer is installed at the entrance to the second mixer of the considered DEPuVRD, and the resonator tube is made with perforation with profiled holes in the area adjacent to the combustion chamber and a partial diffuser opening located in the aerodynamic shadow behind the combustion chamber, with At the same time, a triangular channel with a length of 0.1 to 0.5 of the length of the first mixer pipe is installed inside the inlet section of the first mixer. Both air valves are aerodynamic. Also presented here is a method for forcing a bypass pulsating air-jet engine, including blowing the chamber with an air-fuel mixture of combustion from mixers and air from the aerodynamic valve of the second circuit, which forms an air jet blowing of the combustion zone, subsequent ignition and explosion with the release of combustion products through a resonator tube, pipes - mixers and an aerodynamic valve, while the supply of fuel during operation of the known DEPuVRD is carried out simultaneously into two DEPuVRD circuits, followed by the organization of intensive mixing in the combustion chamber by jet blowing the combustion zone with an air-fuel mixture with the formation of annular vortices.

In the considered closest analogue, there are possibilities for additional increase in the reactive thrust of the DEPuVRD.

It is possible to increase the specific and frontal thrust and reduce the specific fuel consumption by increasing the amplitude of pressure pulsations, which is achieved by increasing the burning rate. An increase in the pulsation amplitude leads to an increase in the thermodynamic efficiency and, accordingly, to a decrease in the specific fuel consumption. Therefore, a natural technical solution is to increase the concentration in the combustible mixture of a gas that has a high burning rate and is capable of accelerating the combustion process in a mixture with other combustible components. Such a gas may in particular be acetylene. This gas has a high burning rate and is distinguished by its exceptional tendency to detonation combustion. Even in small quantities, it is able to accelerate combustion up to detonation. So it is known that the addition of 0.2% acetylene to carbon monoxide makes it capable of detonation combustion.

The technical result achieved as a result of the implementation of the group of proposed inventions is to increase the thermodynamic efficiency by increasing the amplitude of pressure pulsations occurring due to an increase in the combustion rate.

The technical problem is solved by implementing in the combustion chamber of the engine a process known in the chemical industry as "oxidative pyrolysis of methane", as a result of which acetylene is obtained from methane. This process is described in the given sources [1,2,3]. The chemical formula of the process is given below.

6CH ₄ + 4O ₂ \u003d C ₂ H ₂ + 8H ₂ + 3CO + CO ₂ + 3H ₂ O

Zootechnically, this process is realized with a sharp cooling of a burning over-enriched mixture of methane. As a result of stopping the decomposition of methane molecules, acetylene is released. The described process is implemented in two zones of the combustion chamber, the first is located in the second mixer and is a set of cooled plates, the second is on the rear end cover and is a cooled channel.

The specified technical result, in the implementation of the invention, is achieved by the fact that in the known method of forcing a dual-circuit ejector pulsating air-jet engine (DEPuVRD, hereinafter, to the text of the formula and abstract - the engine), including purging the chamber with an air-fuel mixture of combustion from mixers and air from the aerodynamic valve of the second circuit, which forms an air jet blowing of the combustion zone, subsequent ignition and explosion with the ejection of combustion products through the resonator tube, mixers and an aerodynamic valve, during which the products of incomplete combustion are partially sent to the cooled channel and to a set of cooled plates in the second mixer, where due to oxidative pyrolysis of methane takes place, and the resulting gases, including acetylene on the suction stroke, fall back into the combustion chamber, where they cause an increase in the combustion rate.

The implementation of the forcing method described above is carried out in the design of the DEPuVRD containing a combustion chamber, an intake system of the first and second mixers, aerodynamic valves, a fuel manifold and fuel supply nozzles, while a set of cooled plates is installed at the outlet of the second mixer, and on the rear end wall of the chamber combustion, cooled channel.

Comparison of scientific, technical and patent documentation on the date of priority in the main and adjacent headings of the MKI shows that the totality of the essential features of the claimed solution was not previously known, therefore, it meets the condition of patentability "novelty".

An analysis of known technical solutions in this field of technology has shown that the proposed device has features that are absent in known technical solutions, and using them in the claimed set of features makes it possible to obtain a new technical result, therefore, the proposed technical solution has an inventive step compared to the existing level. technology.

The proposed technical solution is industrially applicable, because can be manufactured industrially, workable, feasible and reproducible, therefore, meets the condition of patentability "industrial applicability".

Other features and advantages of the claimed invention will become clear from the following detailed description, given solely in the form of a non-limiting example and with reference to the accompanying drawing illustrating the preferred embodiment, which shows a diagram of the proposed DEPUWRD.

In FIG. 1 shows the claimed DEPuVRD.

In FIG. 2 shows a view - A - on the triangular channel of the first inlet pipe - mixer.

In FIG. 3 shows a view - B - of a partial diffuser opening of the resonator tube.

In FIG. 4. View - C is shown on a set of cooled plates.

In FIG. 5. view is shown - D on the cooled channel.

The positions in the drawing show:

Pos. 1 - gas supply nozzle,

Pos. 2 - the first inlet pipe - mixer,

Pos. 3 - triangular channel,

Pos. 4 - second inlet pipe - mixer,

Pos. 5. - cooled plates,

Pos. 6. - annular shell,

Pos. 7. - combustion chamber,

Pos. 8. - rear wall of the combustion chamber,

Pos. 9. - cooled channel,

Pos. 10. - resonator tube,

Pos. 11. - glow plug,

Pos. 12. - partial diffuser opening,

Pos. 13. - gas heating coil,

Pos. 14. - vortex aerodynamic valve

Pos. 15. - fuel supply nozzle

Pos. 16. - fuel manifold.

DEPuVRD shown in Fig. 1, contains a gas supply nozzle 1 with a coaxially fixed first inlet pipe - a mixer 2 with a triangular channel 3 installed in its front part, a second inlet pipe - a mixer 4 with cooled plates 5 fixed in it, and on its inlet part an annular shell 6, on a combustion chamber 7 with a rear end wall 8 is fixed to the rear end of the second inlet pipe - a mixer 4. A cooled channel 9 and a resonator tube 10 with a spark plug 11 and a partial diffuser opening 12 are fixed to the rear end wall 8 of the combustion chamber 6. A coil is attached to the resonator tube 10 gas heating 13. An aerodynamic valve 14 is fixed on the front wall of the combustion chamber 7, at the inlet to which a fuel supply nozzle 15 from the fuel manifold 16 is installed.

With a partial supply of gaseous fuel through the coil 13 and the supply of a spark to the glow plug 11, the fuel ignites and combustion occurs inside the combustion chamber 7. After some time, the gas heating coil 13 and the walls of the combustion chamber 7 heat up, and a further increase in the fuel supply leads to the implementation of the working cycle of the proposed DEPuVRD. It is carried out as follows.

The supplied gas through the gas supply nozzle 1 ejects air into the first circuit - into the first inlet pipe-mixer 2 and the second inlet pipe - mixer 4, which also perform the function of an aerodynamic valve in the claimed DEPuVRD. Further, the jet flow of the air-gas mixture reaching the rear end wall 8, the combustion chamber 7 collides with it and, turning around, is ignited by the return flow of combustion products from the resonator tube 10. Then the air-fuel mixture explodes and gas is released in four directions.

The first direction is the resonator tube 10. The ejection in this direction is productive, it creates jet thrust and vacuum for the subsequent purge process.

The second direction is to the inlet pipes - mixers 2 and 4. At the stage of the work process, the gas ejected through the second pipe - mixer 4 is a mixture of partially burned and burning pyrolysis products of gasoline that has passed in the coil 13. As you know, gasoline during pyrolysis decomposes into three the main components are methane, ethylene and propylene with a content of approximately 25-30% each. The high-temperature products of combustion of this mixture of gases, flowing onto the plates 5 cooled by the oncoming air flow, are cooled. In this case, the process of further decomposition of methane is interrupted, accompanied by the release of acetylene. The resulting acetylene on the suction stroke returns to the combustion chamber 7 and leads to an acceleration of the combustion process.

The third ejection direction is a vortex aerodynamic valve 14.

The fourth direction of ejection is the cooled channel 9. The burning, over-enriched gas mixture, when moving along the cooled channel 9, goes out from contact with cold walls and cools quickly, which stops the decomposition of methane molecules and produces acetylene, which remains in the volume of the cooled channel 9 on the cycle suction again enters the combustion chamber 7 and leads to an increase in the burning rate.

The described process corresponds to two phases of the working cycle. The first phase is the explosive combustion of the over-enriched gas mixture in the combustion chamber 7, followed by cooling of part of the combustion products on the cooled plates 5 and in the cooled channel 9. The second phase is the suction of part of the combustion products and the resulting acetylene into the combustion chamber 7. Then the cycle repeats.

Of course, the invention is not limited to the described example of its implementation shown in the attached figure. It remains possible to change the various elements, or replace them with technically equivalent ones, without going beyond the scope of the present invention.

Literature:

1. Sokolik A.S. Self-ignition, flame and detonation in gases. - M.: Publishing house of the Academy of Sciences of the USSR, 1960. - 427 p.

2. Mehtiev S.D., Kambarov Yu.G. Olefinic hydrocarbons and their application in the petrochemical industry - Baku: Azerbaijan state. publishing house, 1962.

3. Antonov V.N., Lapidus A.S. Acetylene production. M. Chemistry 1970. - 415 p.

Claims (2)

1. A method for forcing a dual-circuit ejector pulsating air-jet engine (DEPuVRD), including purging the combustion chamber with an air-fuel mixture from mixers and from an aerodynamic valve of the second circuit, which form air jet blowing of the combustion zone, subsequent ignition and explosion with the release of combustion products through a resonator tube, mixers and an aerodynamic valve, characterized in that the process of oxidative pyrolysis of methane is implemented in the combustion chamber, leading to the production of acetylene. 2. Forced double-circuit ejector pulsating air-jet engine (DEPuVRD), containing a combustion chamber, an intake system from the first and second mixers, aerodynamic valves, a fuel manifold and fuel supply nozzles, characterized in that cooled plates are installed at the outlet of the second mixer, and on the rear wall of the combustion chamber - a cooled channel.

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