RU2563092C2 - Method of detonation-deflagration combustion and detonation-deflagration ramjet engine - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: claimed process consists in that supersonic approach airflow is braked in the air intake curvilinear chamber, in the area of speed formation lower that speed of detonation wave generated at combustion but lower than that of shock wave produced at detonation wave suppression. Fuel is continuously fed via fuel nozzles and mixed with air to create a continuous flow of combustible mix with zone of poor mixing in fuel nozzles area and zone of fine mixing located downstream of mix flow. Combustible well-mixed mix is ignited. Detonation wave developed thereat and moving against the flow is suppressed in said poor-mixing zone to produce shock wave and sources of deflagration combustion carried by the flow downstream. Well-mixed combustible mix is ignited by said sources of deflagration combustion to initiate a new detonation wave to propagate against the flow for changeover from detonation to deflagration combustion. This causes detonation-deflagration combustion with pulsation frequency defined by the speeds of detonation wave and supersonic flow.

EFFECT: simplified design, pulsations of detonation wave without application of mechanical or gas-dynamic valves at continuous fuel feed.

2 cl, 2 dwg

Description

The invention relates to pulsating detonation aircraft engines. More precisely, the invention relates to a method for organizing detonation-deflagration combustion and detonation-deflagration pulsating ramjet engine, which does not use mechanical valves or gas-dynamic blocking of fuel channels when creating pulsations.

A known method of organizing a detonation mode of combustion in a combustion chamber of a supersonic ramjet engine (RF patent No. 2285143, publ. 10.10.2006), which includes the supply of fuel-air gas mixture to the combustion chamber of the engine, the generation of internal shock waves in the flow part of the combustion chamber formed by adjustable elements of the combustion chamber. In the flow part of the combustion chamber, a system of symmetrical inclined incident shock waves is created. In the central part of the cross section of the combustion chamber as a result of the interaction of these waves with each other, an overdriven detonation wave, the Mach leg, is formed with the possibility of controlling its size and location in the flow part of the combustion chamber. The size of the Mach legs, and thus its position in the longitudinal direction of the combustion chamber, as well as its stationarity, is set by changing the geometric parameters of the control elements of the combustion chamber depending on the Mach number of the stream at the entrance to the combustion chamber and the chemical composition of the incoming fuel-air gas mixtures.

Known supersonic pulsating detonation direct-flow (SPDD) jet engine (SPDVRD) (RF patent No. 2157909, publ. 20.10.2000), which contains a supersonic air intake, a supersonic mixing chamber, a supersonic combustion chamber, a supersonic nozzle, an engine start device and a feed system fuel. The fuel supply system contains pylons with nozzles and valves for changing the fuel supply mode. There is a known method of functioning of this supersonic pulsating detonation ramjet engine in which at the moment of engine start fuel is supplied and a detonation wave is initiated, further engine operation is provided sequentially from time to time, changing the fuel supply, realizing a rich and lean fuel-air mixture in the combustion chamber and causing changes in the direction and velocity of the detonation wave relative to the combustion chamber from its output to the input through the rich mixture and in the opposite direction in the lean mixture, in the extreme case - in clean air, while maintaining the direction of the wave against the fuel flow.

Known pulsating detonation ramjet engine (RF patent No. 2476705, publ. 02.27.2013), which contains a supersonic air intake, a supersonic mixing chamber, a supersonic combustion chamber, an exhaust supersonic nozzle, a fuel-air mixture igniter and a fuel supply system. The fuel supply system includes headers and pylons with fuel channels and nozzles installed in a supersonic mixing chamber. The engine also comprises a gas duct located between the supersonic air intake and the supersonic mixing chamber. Pylons of the fuel supply system are located at the outlet of the latter. The igniter of the fuel-air mixture is placed in a supersonic combustion chamber in a transverse niche and is made continuously working. The nozzles of the fuel supply system are made open with the possibility of gas-dynamic overlap.

In known technical solutions, detonation combustion is organized by changing the fuel supply to the ramjet. The pulsation of the detonation wave is organized by changing the fuel supply, for which they use mechanical valves or gas-dynamic blocking of the fuel channels. "Gas-dynamic valve" - a shock wave, which at each cycle, completely interrupting the supply of fuel, which reduces traction, moves to the air intake and can disrupt its operation.

The basis of the invention is the simplification of the design of a detonation pulsating ramjet ramjet engine by creating detonation-deflagration combustion and detonation-deflagration pulsating ramjet ramjet engine.

The technical result is the functioning of the pulsation of the detonation wave without mechanical or gas-dynamic valves during continuous supply of fuel and the prevention (due to the selection of the degree of braking of the high-speed flow in the air intake) of the shock wave resulting from this to the fuel nozzles and air intake. Other technical results are increased thrust due to the continuous flow of fuel and a high frequency of the process, determined by the high speeds of the detonation wave and supersonic flow, demolishing foci of slow combustion.

The problem is solved by organizing detonation-deflagration combustion in an air-jet engine for high flight speeds, for which the incident high-speed supersonic air flow is inhibited in the curvilinear space of the air intake as it moves forward, in the formation zone of the velocity less than the speed of the detonation wave, arising from combustion, continuously supply fuel, which is mixed with air, and create a continuous flow of a combustible mixture having a zone of insufficient mixing with the images With a “lean” mixture in the fuel injection area and a well-mixed fuel mixture in an area located downstream of the stream, a well-mixed fuel mixture is ignited, which forms a detonation wave moving at a speed higher than the speed of the fuel mixture and propagating together with the shock wave against flow, quenched when entering the zone of insufficient mixing due to self-extinguishing in the "poor" mixture, and foci of slow deflagration combustion that occur during quenching and are carried down by the oncoming flow June, fall into a well-mixed combustible mixture, ignite it and initiate a new detonation wave propagating upstream, realizing a transition from deflagration to detonation, as a result of which a pulsating process of detonation-deflagration combustion with a high frequency, determined by the high speeds of the detonation wave and supersonic flow, is organized to the fuel nozzles and air intake.

It is advisable if the fuel is supplied in the zone of formation of speed, relatively large Mach numbers (M = 3-4).

The problem is also solved by the fact that the detonation-deflagration pulsating ramjet engine for high flight speeds includes sequentially placed supersonic air intake, a fuel supply system with pylons and sound or supersonic nozzles, supersonic mixing and combustion chambers and an exhaust nozzle that are structurally adapted to implement the above method of organizing detonation-deflagration combustion.

It is advisable that the fuel nozzles are located at the inlet of the mixing chamber and are made open for constant supply of fuel into the flow at the required flow rate, and the supersonic flow rate in the mixing chamber is designed with the supersonic flow velocity at which the shock wave arising from the extinction of the detonation wave after it getting into the zone of an insufficiently mixed combustible mixture does not reach the fuel pylons and the air intake, and the air intake is designed so that its circuit slows down the oncoming high-speed th air flow to a Mach number (M = 3-4) and the speed slower than the speed of the detonation wave, but most of the shock wave velocity arising during extinction of the detonation wave.

The invention is further explained by the description and figures, where, in FIG. 1 and FIG. 2, respectively, the general and internal circuits of a detonation-deflagration pulsating ramjet ramjet engine for carrying out the method according to the invention are shown.

The following is an example of the method and detonation-deflagration pulsating ramjet engine for the implementation of the method.

The method of organizing detonation-deflagration combustion, according to the invention, can be implemented in a pulsating detonation-deflagration ramjet engine for high flight speeds, which contains sequentially placed supersonic air intake 1, a fuel supply system 2 with pylons and nozzles, supersonic mixing chambers 3 and combustion 4, and exhaust supersonic nozzle 7.

Fuel nozzles are placed at the beginning of the mixing chamber 3. The igniter of the combustible mixture 6 is placed at the end of the combustion chamber 4 in the transverse niche 5 and is intended to be launched.

According to the invention, in a supersonic air stream after an air intake 1 inhibiting a high-speed incoming flow, from the sound or supersonic fuel nozzles of the system 2 are continuously fed into the fuel and mixed with air in the mixing chamber 3. This creates a continuous flow of combustible mixture having an insufficient mixing zone with the formation of a "poor" mixture in the fuel injection area (at the fuel nozzles of system 2) and a well-mixed combustible mixture in the zone located downstream. A well-mixed combustible mixture is primarily ignited by the igniter 6. During ignition, a combustion process is organized with the formation of shock (SW) and detonation waves (DW). The resulting detonation wave moves at a speed above the flow rate of the combustible mixture and propagates along with the shock against the flow. When entering the zone of insufficient mixing (at the fuel nozzles of system 2), the detonation wave is quenched due to its self-quenching in the “poor” mixture. A rarefaction wave (BP) is formed, contact discontinuity (RC) and a slow combustion front (FG). The foci of slow deflagration combustion that occur during extinction, the incoming flow of the combustible mixture carries them downstream, where they enter the well-mixed combustible mixture, ignite it and initiate a new detonation wave propagating against the flow, realizing a transition from deflagration to detonation, as a result of which a pulsating process of detonation-deflagration combustion is organized with a high frequency determined by the high speeds of the detonation wave and supersonic flow to the fuel nozzles and air intake ika.

It is advisable if the fuel is supplied in the zone of formation of speed, relatively large Mach numbers (M = 3-4).

The detonation wave (DW) goes out when it gets into the zone of insufficient mixing, the shock wave (SW) arising from this cannot overcome the supersonic flow and reach the fuel nozzles and air intake. The detonation wave (DW) moves along the combustion chamber 4 and part of the mixing chamber 3. When it enters the zone of insufficient mixing, the detonation wave self-extinguishes due to falling into the “poor” mixture.

The passage of the shock wave into the air intake 1 is prevented by a supersonic flow in the mixing chamber 3 with a specially selected Mach number. Due to the selection of the degree of inhibition of the high-speed flow in the air intake 1, the shock wave arising from the quenching does not reach the fuel nozzles and the air intake.

The engine is adapted to implement the method by known calculation means by changing the geometric parameters of the control elements of the combustion chamber depending on the Mach number of the stream at the inlet of the combustion chamber and the chemical composition of the incoming fuel-air gas mixture and experiments (see: 1. Netleton M. Detonation in gases / Under the editorship of LG Gvozdeva. M: Mir, 1989. P. 15, 33-39; 2. Mitrofanov VV Detonation of homogeneous and heterogeneous systems. Novosibirsk: IGL SB RAS, 2003. 199 p. ; 3. Vasiliev AA Features of the application of detonation in engines p.129, 141-145; 4. Levin V.A. et al. Initiation of gas detonation by electric discharges. P.235-254; 5. Bykovsky F.A. et al. Initiation of detonation in hydrogen-air flows mixtures. S.521-539 / Pulse Detonation Engines. Edited by S. M. Frolov. M.: Torus-Press, 2006. 592 p.).

In the case of the best execution, the fuel nozzles of the system 2 were located at the inlet of the mixing chamber 3 and were made open for the constant supply of fuel into the stream with the required flow rate. The supersonic flow rate in the mixing chamber 3 is calculated with the supersonic flow velocity at which the shock wave arising from the extinction of the detonation wave after it enters the zone of insufficiently mixed combustible mixture does not reach the fuel pylons and to the air intake 1. The air intake 1 is made so that its circuit inhibits the oncoming high-speed air flow to Mach numbers (M = 3-4) and a speed that is less than the speed of the detonation wave, but greater than the speed of the shock wave that occurs when the detonation is extinguished constant wavelength.

This design extends the range of flight speeds of the aircraft to Mach numbers 5-8.

The method of operation of a detonation-deflagration pulsating ramjet engine for high flight speeds consists in supplying air to the inlet of the supersonic mixing chamber 3 through the supersonic air intake 1 and fuel through the fuel nozzles of the system 2. Behind the nozzles, a combustible mixture is formed in the supersonic mixing chamber 3, directed to the combustion chamber 4, and the niche 5 is filled. In the niche, the igniter 6 initiates primary ignition and combustion of the mixture, which passes into detonation. Further engine operation is ensured by directing the resulting detonation wave against the flow due to the choice of its supersonic speed lower than the speed of the detonation wave. After entering the zone of insufficient mixing near the fuel nozzles, the detonation wave dies away, generating a shock wave that moves against the flow at a speed less than the speed of a supersonic flow. The flow demolishes a contact rupture with foci of slow burning close to it and a rarefaction wave. The foci of slow burning arising during the extinction of the detonation wave are carried away by the stream to the zone of good mixing, where a “rich” combustible mixture is formed. When the engine operates on a “rich” combustible mixture, the foci form a continuous front, realize the transition from deflagration to detonation, ensuring the frequency of the process. Thus, the detonation wave always moves against the flow between the cross section of the transition from deflagration to detonation (SW cross section) and the cross section of the insufficiently mixed mixture near the fuel nozzles of system 2, where the existence of a detonation wave is impossible.

To support research on detonation engines, an experimental setup has been created that simulates the operation of mixing and combustion chambers in the “connected pipeline” mode (the supersonic air flow at the inlet to the mixing or combustion chambers creates a supersonic nozzle). When modeling the work of the proposed method on it, it was found that with a constant supply of hydrogen fuel for air excess coefficients from 1 to 1.4, a pulsating process with damping and re-emerging detonation waves going upstream is realized. A steady pulsating mode of operation is realized, which is obviously more high-frequency than in SPDDRD.

For the working process, one can expect high fuel efficiency, completeness of combustion and temperature of the combustion products.

At flight Mach numbers M = 5–8, the combustion process that is required requires less drag than in ramjet ramjet (ramjet engine) and ramjet ramjet (ramjet with supersonic combustion) (to M = 3-4 at the outlet of the air intake), reducing heat stress tract of the engine.

Thus, the present invention in the absence of providing pulsating operation of the engine mechanical valves:

expands the range of flight speeds of aircraft to Mach numbers M = 5-8;

when the flight Mach numbers M = 5-8 reduces the heat stress of the engine path;

provides constant fuel consumption and preventing shock waves moving against the flow to the air intake.

Claims (2)

1. The method of organizing detonation-deflagration combustion in an air-jet engine for high flight speeds, which consists in the fact that the incoming high-speed supersonic air flow is inhibited in the curved space of the air intake, as it moves, in the formation zone of the velocity, less than the speed of the detonation wave, arising during combustion, but greater than the velocity of the shock wave arising from the quenching of the detonation wave, fuel is continuously supplied through the fuel nozzles, mixed with air and create a continuous flow of a combustible mixture having a zone of insufficient mixing in the area of the fuel nozzles and a zone of a well-mixed fuel mixture located downstream of the stream, ignite a well-mixed fuel mixture, the resulting detonation wave moving against the stream, quench in the zone of insufficient mixing with the formation shock waves and foci of deflagration combustion, carried downstream, ignite a well-mixed combustible mixture with the indicated foci of deflagration combustion and initiate -hand detonation wave that propagates against the flow, thereby realizing a transition from deflagration to detonation combustion, as a result of the process is provided by deflagration-detonation combustion pulsations at a frequency determined by the speed of the detonation wave and supersonic flow. 2. Detonation-deflagration pulsating ramjet engine for high flight speeds, including sequentially placed supersonic air intake, fuel supply system with pylons and sonic or supersonic fuel nozzles, supersonic mixing and combustion chambers and an exhaust nozzle, characterized in that the geometric parameters are curved the air intake spaces are selected based on the formation conditions in the area of the fuel nozzles where the flow rate is lower than soon be a detonation wave produced by combustion, but greater than the velocity of the shock wave formed in the quench of the detonation wave and fuel nozzles are arranged to form a zone near them insufficient mixing of air and fuel flows.

Images