RU2553589C2 - Method of functioning of supersonic pulsing detonation straight-jet engine - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: invention relates to methods of functioning of supersonic pulsing detonation straight-jet engines, mainly when flying at Mach number above 6. The method of functioning of the supersonic pulsing detonation straight-jet engine according to which the fuel is supplied to the main supersonic combustion chamber where the pulsing process is performed, for this purpose an antechamber is used which is installed upstream the main supersonic camera. A part of fuel is supplied into the antechamber, a pulsing flow is obtained and superimposed on a flow in the main supersonic combustion chamber. The antechamber is designed as a valve chamber with a constant fuel combustion volume the number of working cavities of which is selected according to the required frequency of pulsations in the main supersonic combustion chamber. The flow from the antechamber is divided and sent to the main supersonic chamber in the axial and radial directions.

EFFECT: invention provides stable burning in a supersonic flow of the aviation fuel - kerosene - without oxidising gas, without air pre-heating.

2 dwg

Description

The present invention relates to methods of functioning of supersonic pulsating detonation ramjet engines, mainly when flying with a Mach number of more than 6.

A known method of functioning of a supersonic pulsating detonation ramjet engine, which consists in the fact that at the time of engine start supply fuel and initiate a detonation wave. Further engine operation is ensured sequentially periodically, changing the fuel supply, realizing a rich and poor air-fuel mixture in the combustion chamber and causing a change in the direction and velocity of the wave relative to the combustion chamber from its exit to the input through the rich mixture and in the opposite direction along the lean mixture, to the limit the case is in clean air, while maintaining the direction of movement of the wave against the stream (RF Patent 2157909, IPC ⁷ F02K 7/14, filed May 26, 1999, publ. October 20, 2000).

To ensure stabilization of combustion and completeness of fuel combustion, shock waves in a supersonic flow must propagate at a speed of at least 1000 m / s and with a high frequency, which is difficult to implement when implementing this method, because the frequency of wave generation is limited by the frequency of fuel supply, which depends on the capabilities of the fuel equipment. So, when the length of the combustion chamber is two meters, the fuel supply should change with a frequency of more than 1000 Hz. At lower frequencies, the wave can be carried outside the combustion chamber. Moreover, the greater the required fuel consumption, the more difficult it is to ensure a high frequency of fuel supply. This negatively affects the overall mass characteristics of the fuel equipment and complicates its design.

In addition, this method is difficult to implement when using hard-to-detonate kerosene-air mixture as fuel. For the organization of detonation in the entire stream of the mixture requires a powerful source of energy with a speed of its release, as in explosives.

There is also a known method of functioning of a supersonic pulsating detonation ramjet engine in which fuel is supplied to the main combustion chamber and a pulsating process is carried out in it. To create a pulsating process, a pre-chamber is used, which is installed at the entrance to the main chamber, part of the fuel is fed into it, a pulsating flow is obtained and imposed on the flow in the main combustion chamber. A tube pulsating detonation device (tube) is used as a pre-chamber, and an easily detonated oxygen-kerosene mixture is used as fuel (“Works of the leading aircraft engine building companies to create promising aircraft engines.” M.: TsIAM, 2004, pp. 381-382) .

However, tubular pulsating detonation devices have several disadvantages. These inlet devices use mechanical valves to facilitate knock control, which increases the complexity and cost of the device and also limits the knock frequency to 10 Hz, which cannot provide stable combustion in a supersonic flow. Low detonation frequencies can have a detrimental effect on the structural elements of the propulsion system, as knocks and vibrations are generated during detonations.

Moreover, tubular pulsating detonation devices do not work efficiently on commonly used aviation fuel - kerosene, because additional component is required - oxidizing gas, namely oxygen, which increases its detonation ability.

Also, this method does not allow you to create the required temperature in the main combustion chamber without additional heating of the air-fuel mixture, which ensures stable combustion in the supersonic stream of aviation fuel - kerosene.

The technical result to which the invention is directed is to ensure stable combustion in a supersonic stream of aviation fuel - kerosene without oxidizing gas, without preliminary heating of the air due to the complex effect of gas jets, shock waves that increase the temperature of the mixture in the main supersonic combustion chamber on the flow of the air-fuel mixture , and detonation waves, the frequency of which ensures their constant presence in it.

To achieve the named technical result, when implementing the method of functioning of a supersonic pulsating detonation ramjet engine, fuel is supplied to the main combustion chamber and a pulsating process is carried out in it. To implement the pulsating process, a pre-chamber is used, which is installed at the entrance to the main chamber, part of the fuel is fed into it, a pulsating flow is obtained and imposed on the flow in the main combustion chamber.

New in the invention is that the pre-chamber is made in the form of a spool chamber with a constant volume of fuel combustion, the number of cavities in which is selected in accordance with the required pulsation frequency in the main chamber. The pulsating stream obtained in the pre-chamber is separated and directed into the main chamber in axial and radial directions.

The accompanying drawings show:

figure 1 - supersonic pulsating detonation ramjet ramjet engine, General view;

figure 2 is a view A figure 1 is a device for implementing the method.

A device for implementing the method comprises a combustion chamber 1 with a constant volume of fuel combustion, mounted on pylons 2 of the fuel supply at the entrance to the main supersonic chamber 3 SPDP WFD.

The pre-chamber 1 contains an input device 4, a housing 5 with an input 6 and an output 7 windows and a flame-retarding channel-receiver 8. A fuel nozzle 9, an ignitor 10, are located on the housing 5, and a spool 11 with working cavities 12 is installed in the housing 5 for rotation, the number of which It is determined based on the required frequency of working pulsations: the higher the required frequency, the greater the number of cavities. The pre-chamber 1 is equipped with an output device 13, in communication with the entrance to the main supersonic combustion chamber 3 through the axial channel 14. Radial holes 15 are also made in the walls of the output device 13 for forming radial gas jets.

The method is as follows.

In the main chamber 3 of the pylons 2 serves fuel - aviation kerosene, part of the fuel is served in the chamber 1.

During the operation of the pre-chamber 1, the spool 11 rotates and sequentially communicates each of its working cavities 12 with an input window 6. with a fuel nozzle 9, an igniter 10 and an output device 13.

In the spool 11, fuel is burned at a constant (closed) volume, while the pressure rises.

To increase the reactivity of gas jets in the spool 11, a re-enriched air-fuel mixture can be burned with the formation of chemically highly active fuel in the combustion products.

After fuel combustion, when the window of the working cavity 12 is combined with the exit window 7, a supersonic flow of gas jets (mixture of products of combustion with a chemically highly active fuel) occurs from the outlet device 13 into the main supersonic chamber 3 through the channel 14 in the axial direction and through the radial holes 15 in the radial directions . The axial stream of fuel forms a shock wave in the main supersonic chamber 3, which propagates through the main chamber and increases the pressure and temperature of the mixture in it, creating conditions for its ignition. Numerous radial gas jets from the radial openings 15 of the output device 13 involve a large volume of the mixture in the reaction and cause its explosive combustion. Shock waves from the pre-chamber 1 enter the main supersonic chamber 3 with a frequency that ensures their constant presence in the main chamber 3.

Thus, in the main supersonic chamber 3 there is a constant pulsating effect on the flow of the air-fuel mixture of shock waves from an axial gas jet increasing its temperature, radial gas jets containing chemically highly active fuel, affecting the mixture and the resulting detonation waves, which ultimately increases the rate of combustion of the mixture.

This method allows for stabilization of combustion in a supersonic stream of aviation fuel - kerosene.

Claims (1)

The method of functioning of a supersonic pulsating detonation ramjet engine, in which fuel is supplied to the main supersonic combustion chamber and a pulsating process is carried out in it, for which a precamera is used, which is installed at the entrance to the main supersonic chamber, part of the fuel is fed into it, a pulsating flow is obtained and impose it on the flow in the main supersonic combustion chamber, characterized in that the pre-chamber is made in the form of a spool chamber with a constant volume Goran fuel, the amount of work chambers which are selected according to the desired pulsation frequency in the supersonic main combustion chamber, the flow from the antechamber is separated and fed into the main chamber at supersonic axial and radial directions.

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