RU2754796C1 - Method for forcing two-circuit ejector pulsating air-jet engine and forced two-circuit ejector pulsating air-jet engine - Google Patents

Abstract

FIELD: aircraft engineering.

SUBSTANCE: invention relates to aircraft engines and can be used as an engine of small unmanned aircraft, such as, for example, unmanned reconnaissance aircraft, flying targets. The method involves purging the combustion chamber with a fuel-air mixture from mixers and air from the aerodynamic valve of the second circuit, forming an air jet blowing of the combustion zone, subsequent ignition and explosion with the release of combustion products through the resonator pipe, mixers and an aerodynamic valve, while the fuel supply during engine operation is carried out simultaneously in two circuits of the TCEPAJE, followed by the organization of intensive mixing in the combustion chamber by jet blowing with a fuel-air mixture of the combustion zone with the formation of annular vortices. A distinctive feature is that a cavity is arranged in the combustion chamber, in which the preheating of the fuel-air mixture is carried out and the combustion process is switched to the detonation mode, and at the exit from the organized cavity, the combustion products are inhibited. The TCEPAJE contains, in particular, a combustion chamber, an inlet system from the first inlet pipe-mixer and the second intake pipe-mixer, aerodynamic valves, a fuel collector and a fuel supply nozzle. A distinctive feature is that the outlet section of the second inlet pipe-mixer is made elongated and partially placed directly in the volume of the combustion chamber in such a way that a cylindrical cavity is formed between it, the front wall of the combustion chamber and its bottom part, in which the Shchelkin spiral is installed. The fuel supply nozzle can be placed directly in the cylindrical cavity formed in the combustion chamber.

EFFECT: invention achieves an increase in thermodynamic efficiency.

3 cl, 2 dwg

Description

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

Known pulsating jet engine (hereinafter PuVRD) German cruise missile during the Second World War V-1 (see GB Sinyarev, MV Dobrovolsky. Liquid rocket engines. - Oborongiz, 1957, pp. 19, 20) ... It is a channel with a circular cross-section open at both ends, which includes a sequentially located inlet diffuser, a valve grate, a combustion chamber and an outlet device consisting of a confuser and an exhaust pipe, as well as a fuel supply system and an ignition system with an electric igniter installed in the combustion chamber. In the general case, the input and output devices of the PUVRD can have a shape that differs from the prototype, therefore, in what follows, we will call them by the accepted terms - air intake and nozzle.

The valve lattice is a structure of supporting elements - transverse rods, moving elements - flat elastic plates of constant thickness, attached to the lateral 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 of plates parallel to them. Each pair has a blind gap facing backwards between the plates. The plates and spacers form longitudinal air ducts.

The flow on the engine passes through the air intake and the valve grate into the combustion chamber. Volatile fuel is supplied there, after which the air-fuel mixture is ignited by an electric igniter spark. Combustion products rapidly expanding in all directions, falling into the blind gap between the plates, are inhibited, as a result of which the pressure there increases. This causes the plates to bend laterally until they contact the support spacers or side walls. The air channels of the valve grate are blocked. The combustion products flow out through the nozzle into the atmosphere, and their pressure on the closed valve lattice creates a thrust impulse of the engine.

After a drop in pressure, the plates of the valve lattice, under the action of their elasticity, as well as the vacuum 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 advantages of PUVRD with mechanical valve grids are simplicity and low cost, low weight, reliability and high hydraulic resistance to combustion products trying to break through against the incoming flow during an explosion in the combustion chamber.

Their disadvantage is high hydraulic resistance when blowing out the combustion chamber, which leads to a low cyclic volumetric filling and, as a consequence, to a low specific and frontal thrust. But the main thing is that they give a drop in thrust at high flight speeds due to mechanical bending by the dynamic air pressure of the valve blades, which leads to a transition to the operation mode of the direct-flow BP D.

Also known are the design of PUVRD using aerodynamic valves, "Pulsating air-jet engines", ed. K.V. Migalina, - Togliatti: TSU Publishing House, 2014, p. 81. In addition, PuVRD, in which the replacement of mechanical valves with aerodynamic ones, is described in US patents No. 2796735, 1957; No. 2796734, 1957; No. 2746529, 1956; No. 2822037, 1958; 2812635, 1957; 3093962, 1963.

The disadvantages of such PUVRDs include a low amplitude of pressure pulsations and, accordingly, a low thermodynamic efficiency (efficiency) caused by significant losses of fuel emitted from the intake system.

Known device for a forced by-pass ejector pulsating air-jet engine protected by patent for invention RU 2717479, SPK F02K 7/067 (2020.01), published 03/23/2020, BI No. 9. The forced by-pass ejector pulsating air-jet engine (DEPuVRD) contains, in particular, a combustion chamber, an intake system from 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 partial diffuser opening. A distinctive feature of this DEPuVRD is that the rear wall of the combustion chamber is made with the first visor of the echelon with rectangular slots for the formation of flat jet flows behind them, inside the combustion chamber behind the first visor there is a perforated niche with a second visor protruding into the flow, and the fuel heating coil has an uneven in diameter and oblique along the axis of the winding.

As the closest analogue (prototype), a device for a forced by-pass ejector pulsating air-jet engine (DEPuVRD), protected by the patent for invention RU 2714463 SPK F02K 7/067 (2019.08), published on February 17, 2020, BI No. 5, was chosen, which contains, in particular , a combustion chamber, an intake system from the first and second mixer pipes, aerodynamic valves, a fuel manifold and a fuel supply nozzle. At the entrance to the second mixer of the considered DEPuVRD, an annular shell with a length of 0.3-0.5 caliber of the second mixer is installed, and the resonator tube is made with perforation with profiled holes in the area adjacent to the combustion chamber and partial diffuser opening located in the aerodynamic shadow behind the combustion chamber, when In this case, 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. It also presents a method for forcing a two-circuit pulsating air-jet engine, including purging the chamber with a fuel-air mixture of combustion from mixers and air from an 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 the resonator tube, pipes - mixers and an aerodynamic valve, while the fuel supply during the operation of the known DEPuVRD is carried out simultaneously into two circuits of the DEPuVRD, followed by the organization of intensive mixing in the combustion chamber by jet blowing the combustion zone with a fuel-air mixture with the formation of annular vortices.

In the closest analogue, there are opportunities to increase the thermodynamic efficiency (efficiency) and, accordingly, reduce the specific fuel consumption.

The technical result achieved as a result of the implementation of the proposed complex of inventions is to increase the thermodynamic efficiency due to the preliminary heating of the air-fuel mixture in the inlet mixer pipe and the transition of combustion to detonation.

The technical problem is solved by changing the design of the combustion chamber.

In the claimed complex of inventions, in the known method of forcing a two-circuit ejector pulsating air-jet engine (DEPuVRD), including purging the combustion chamber with a fuel-air mixture from the first and second mixer pipes and air from the aerodynamic valve of the second circuit, which forms an air jet blowing of the combustion zone, the subsequent ignition and explosion with the release of combustion products through the resonator tube, mixer pipes and an aerodynamic valve, while the fuel supply during operation of the DEPuVRD is carried out simultaneously in two DEPuVRD circuits with the subsequent organization of intensive mixing in the combustion chamber by jet blowing the combustion zone with the air-fuel mixture with the formation of ring vortices, in addition, a cavity is organized in the combustion chamber, in which preliminary heating of the fuel-air mixture and the transition of the combustion process to the detonation mode are carried out, and at the exit from the organized cavity, the combustion products are decelerated. Structurally, this is achieved by the fact that in the known DEPuVRD containing, in particular, a combustion chamber, an intake system from a first inlet mixer pipe and a second inlet mixer pipe, aerodynamic valves, a fuel manifold and a fuel supply nozzle, while the outlet section of the second intake pipe - the mixer is made elongated and partially placed directly in the volume of the combustion chamber in such a way that between it, the front wall of the combustion chamber and its bottom part, a cylindrical cavity is formed in which the Shchelkin spiral is installed.

In a preferred embodiment, the fuel delivery nozzle is located directly in the cylindrical cavity formed in the combustion chamber.

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

Analysis of the known technical solutions in this field of technology showed that the proposed device has features that are absent in the known technical solutions, and their use in the claimed set of features makes it possible to obtain a new technical result, therefore, the proposed technical solution has an inventive step in comparison with the existing level technology.

The proposed technical solution is industrially applicable, since can be industrially manufactured, operable, feasible and reproducible, and therefore meets the "industrial applicability" requirement of patentability.

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

FIG. 1 shows the claimed forced by-pass ejector pulsating jet engine (DEPuVRD).

FIG. 2 shows a cylindrical cavity formed in a combustion chamber (enlarged).

The positions in the drawing show:

Pos. 1 - gas supply nozzle,

Pos. 2 - the first inlet pipe - mixer,

Pos. 3 - triangular channel,

Pos. 4 - the second inlet mixer pipe,

Pos. 5 - annular shell,

Pos. 6 - combustion chamber,

Pos. 7 - visor,

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

Pos. 9 - resonator tube,

Pos. 10 - glow plug,

Pos. 11 - partial diffuser opening,

Pos. 12 - gas heating coil,

Pos. 13 - vortex aerodynamic valve

Pos. 14 - fuel supply nozzle

Pos. 15 - fuel manifold

Pos. 16 - elongated outlet section of the second inlet mixer pipe

Pos. 17 front wall of the combustion chamber

Pos. 18 - the bottom of the combustion chamber

Pos. 19 - cylindrical cavity

Pos. 20 - Shchelkin's spiral.

DEPuVRD shown in Fig. 1, contains a gas supply nozzle 1 with a coaxially fixed first inlet pipe - mixer 2 with a triangular channel 3 installed in its front part, a second inlet mixer pipe 4 with an annular shell 5 fixed on its inlet part, at the rear end of the second inlet mixer pipe 4, a combustion chamber 6 is fixed with a visor 7 and a rear end wall 8. A resonator tube 9 with a spark plug 10 and a partial diffuser opening is fixed to the rear end wall 8 of the combustion chamber 6. A gas heating coil is attached to the resonator tube 9. combustion 6, an aerodynamic valve 13 is fixed, at the inlet to which a fuel supply nozzle 14 from the fuel manifold 15 is installed. combustion 6 and its bottom part 18 formed a cylindrical cavity 19, in which is installed Shchelkin spiral 20.

The claimed DEPuVRD works as follows: the heated fuel from the gas heating coil 12 is sprayed by the fuel supply nozzle 14 and the incoming air flow through the second intake pipe-mixer 4 enters the combustion chamber 6, in which the fuel is burned. Fuel enters the cylindrical cavity 19 of the combustion chamber 6 from the fuel supply nozzle 14, and air flows through the vortex aerodynamic valve 13 at the moment when a vacuum is formed during the operation of the DEPuVRD. Ignition in the cylindrical cavity 19 of the combustion chamber 6 occurs from hot gases in the combustion chamber 6. At the exit from the cylindrical cavity 19, a Shchelkin spiral 20 is installed. Braking of combustion products by the Shchelkin spiral 20 at the outlet promotes combustion acceleration, as it accelerates the movement of unburned gas.

During the combustion of the cylindrical cavity 19, the lower part of the elongated outlet section 16 of the second intake pipe-mixer 4 is heated, which leads to the pyrolysis of the fuel and the improvement of the combustion process.

The implementation of the proposed method consists in the fact that when the combustible mixture is ignited, a normal combustion front appears, moving at a subsonic speed relative to the gas in front of it. Expanding combustion products generate compression waves and cause motion in the gas ahead of the front. Compression waves catch up with each other, forming shock waves. The state ahead of the front changes: the temperature, pressure, gas velocity increase, turbulence arises, which has a significant effect on the development of the combustion process. The flame front is curved and accelerated. Experimental and theoretical studies show that there are cases when the acceleration of the flame ends with the stabilization of the combustion rate at the subsonic level and when the acceleration of the flame leads to a jump-like transition of combustion in detonation. Ignition at a certain small distance from the front wall 17 of the combustion chamber 6 facilitates the occurrence of detonation, since this increases the initial velocity of the unburned gas due to the reflection in the initial period of compression waves from the front wall 17.

Thus, in the inventive method and in a possible embodiment of the DEPuRVD in which it is implemented, the technical problem is solved due to the fact that:

The elongated outlet section 16 of the second inlet pipe-mixer 4 is additionally heated, while pyrolysis of the fuel occurs, leading to an increase in the combustion rate and, as a consequence, to an increase in heat generation and an increase in efficiency.

The presence of an elongated outlet section 16 of the second inlet mixer pipe 4 leads to the formation in the combustion chamber 6 of a cylindrical cavity 19 with a closed front wall 17, during the combustion of fuel in which a normal combustion front appears, moving at a subsonic speed. In this case, the expanding combustion products generate compression waves. Compression waves catch up with each other, forming shock waves. The temperature, pressure, gas velocity rises, which has a significant effect on the development of the combustion process.

At the exit from the cylindrical cavity 17, a Shchelkin spiral 20 is installed, upon impact on which additional shock waves appear, leading to an increase in pressure and temperature.

The graphic part presented in the application materials is not exhaustive information. Various options for design changes are possible that do not go beyond the scope of claims declared by the formula.

Claims (3)

1. A method of forcing a double-circuit ejector pulsating air-jet engine (DEPuVRD), including purging the combustion chamber with a fuel-air mixture from mixers and air from an aerodynamic valve of the secondary circuit, forming an air jet blowing of the combustion zone, subsequent ignition and explosion with the emission of combustion products through the resonator tube, mixers and an aerodynamic valve, while the fuel supply during engine operation is carried out simultaneously into two engine circuits, followed by the organization of intensive mixing in the combustion chamber by jet blowing the combustion zone with a fuel-air mixture with the formation of annular vortices, characterized in that a cavity is organized in the combustion chamber, in which carries out preliminary heating of the fuel-air mixture and the transition of the combustion process to the detonation mode, and at the exit from the organized cavity, the combustion products are decelerated. 2. Forced by-pass ejector pulsating air-jet engine (DEPuVRD), containing, in particular, a combustion chamber, an intake system from the first inlet mixer pipe and the second inlet mixer pipe, aerodynamic valves, a fuel manifold and a fuel supply nozzle, characterized in that, that the outlet section of the second intake pipe-mixer is made elongated and partially located directly in the volume of the combustion chamber in such a way that between it, the front wall of the combustion chamber and its bottom part, a cylindrical cavity is formed, in which the Shchelkin spiral is installed. 3. Forced by-pass ejector pulsating air-jet engine (DEPuVRD) according to claim 2, characterized in that the fuel supply nozzle is placed directly in the cylindrical cavity formed in the combustion chamber.

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