RU192758U1 - Device for ignition and stabilization of supersonic combustion - Google Patents

Abstract

A device for igniting and stabilizing a plasmatron-type supersonic combustion belongs to the field of aeronautical engineering and can be used to provide reliable ignition and stabilizing the combustion of hydrocarbon fuels in supersonic combustion chambers of ramjet engines. At high flow rates, additional energy input into the volume of the combustion chamber channel may be required. The device consists of a fragment of a direct-flow combustion chamber and two pylons protruding into the flow inside the combustion chamber. In the pylons there are tubes with injectors. Injectors located in the first pylon are connected to sources of chemically active additives and main fuel. Only the main fuel is injected through the injector of the second pylon. The use of chemically active additives allows to provide the required energy input into the volume of the combustion chamber. The proposed design of the device allows you to limit the consumption of additives, reducing the cost of their placement on board the aircraft. At the stage of starting the ramjet engine, the plasmatron type ignition device is briefly turned on.

Description

The utility model relates to the field of aviation technology and can be used to provide reliable ignition and stabilization of the combustion of hydrocarbon fuels in supersonic combustion chambers of ramjet engines. When traditional gas-dynamic methods do not allow the combustion process to be organized due to low static temperatures and pressures, as well as high flow rates, additional energy input into the volume of the combustion chamber channel may be required.

The invention is known "A method of stabilizing the process of burning fuel in a combustion chamber and a combustion chamber of a ramjet engine of an aircraft" (RF patent No. 2454607 IPC F23R 3/18, F02K 7/08). A thermochemical reactor using steam conversion of hydrocarbons is used to facilitate ignition of liquid hydrocarbon fuels in the channel of the ramjet combustion chamber. This occurs by separate injection from closely spaced injectors. The disadvantage of this solution is the need for a significant amount of conversion products required for ignition of liquid hydrocarbon fuels.

A device is known (Y. Tian, S. Yang, "Study on the Effect of Air Throttling on Flame Stabilization of an Ethylene Fueled Scramjet Combustor", International Journal of Aerospace Engineering vol. 2015, Article ID 504684) in which a local increase in pressure is achieved in the channel of the combustion chamber by injection of gases (eg air) from the wall, thereby ensuring reliable ignition of the fuel-air mixture. The disadvantage of the technical solution is the need to have a gas source - an additional capacity or an additional air intake reducing the streamlining of the aircraft. The disadvantage is that the injected gases have a low temperature. This does not allow their use for heating fuel-air mixtures while stirring in the channel of the combustion chamber.

A device is also known, (M. Vachon, T. Grindle, C. St. John, D. Dowdell, "X-43A Fluid and Environmental Systems: Ground and Flight Operation and Lessons Learned", AIAA / CIRA 13th International Space Planes and Hypersonics Systems and Technologies Conference, AIAA 2005-3337), in which, for ignition of the main fuel, mixing into a common mixture of a fuel additive with high chemical-kinetic parameters is used. The disadvantage is the need for a significant amount of additives. Bulky containers are required to store large volumes of additional fuels with increased danger.

The closest technical solution is the “Supersonic plasmachemical combustion stabilizer”, (RF patent No. 2499193 IPC F23R 3/18, F23R 3/34, F23Q 5/00, F23D 14/26), which is taken as a prototype by the maximum number of similar essential features. The known stabilizer contains two pylons installed in the combustion chamber channel with symmetrical aerodynamic profiles, one of which is also an electrode isolated from the housing of the combustion chamber. Injectors with tubes are built into one of the pylons, which are connected respectively to the main fuel source and the source of chemically active additives for their injection into the stream. The main disadvantage of this stabilizer is the supply of additives and fuel to the combustion chamber from one pylon, thereby achieving their complete mixing. This leads to increased consumption of additives. Significant disadvantages include the presence of high-voltage electrical insulation of the second pylon and the need to place on board a high-power high-voltage power supply that works for a long time.

The problem to be solved by the claimed invention is directed, and the result obtained by implementing this decision can be achieved by a combination of the claimed essential features necessary and sufficient to achieve a technical result.

The essence is that the claimed technical solution, like the prototype, contains a fragment of a direct-flow combustion chamber 1 with pylons 2 and 3 located in it, in the first of which injectors 4 are connected, connected via separate tubes to the source of chemically active additives 5 and the source of the main fuel 6. In contrast to the prototype, the proposed solution additionally introduces an injector 7 built into the pylon 3, connected via a pipe to the main fuel source 6. To ensure the starting of the ramjet engine to the fragment the burner chamber 1 is connected externally to the plasma torch 8 through the output channel of the plasma 9.

The essence is illustrated by the drawing, which shows a diagram of a device for stabilizing supersonic combustion, which shows:

1 is a fragment of a combustion chamber of a ramjet of a rectangular cross-section (in longitudinal section);

2, 3 - pylons;

4 - injectors of the main fuel and chemically active additives;

5, 6 - sources of chemically active additives and main fuel, respectively;

7 - main fuel injector;

8 - plasmatron type device;

9 - output channel of the plasmatron type device.

During operation of the device, chemical active additives are injected into the combustion chamber 1, which are characterized by high rates of ignition and heat during combustion. These additives are injected into the combustion chamber 1 from the source 5 together with the main fuel from the source 6 through the injectors 4 installed in the pylon 2 in a ratio sufficient to form a stable flame, due to which a pressure zone is also created in the channel. The rest of the fuel without chemical additives (due to which their consumption is reduced compared to the prototype) is supplied from the source 6 through the injector 7 installed in the pylon 3, into the flame-free area of the combustion chamber 1. In this case, a part of the fuel not activated by chemical additives is mixed , with air and ignition of the resulting mixture when interacting with flares of chemically activated fuels downstream. The formation in the channel of a zone of high pressure also contributes to easier ignition of the main fuel, that is, it involves, in addition to fire, a gas-dynamic mechanism of influence on in-chamber processes. The stabilization of the combustion of the main fuel is ensured by the effect of a more stable flame of chemically activated fuel. The plasmatron type device 8 is activated briefly at the start of the ramjet engine to ignite the torch with additional fuel by ejecting the plasma into the air-fuel mixture through the plasma outlet channel 9.

Chemical additives can be flammable fuels, including hydrogen, contained in the products of steam reforming of hydrocarbons at high temperatures (about 1000 C). It is possible to use compounds with a lower decomposition temperature, for example, ammonia, as well as complex hydrides as a source of hydrogen. Preliminary tests of additional fuels were carried out and estimates were obtained that can confirm the possibility of realizing the expected effect using the proposed device.

Thus, the positive effect of the claimed technical solution, namely: ignition and stabilization of supersonic combustion, is ensured by the ignition of fuel in a supersonic flow and the maintenance of combustion using chemically activated flares in ramjet engines with supersonic flow in the channel of combustion chamber 1, including and in regimes with low static temperatures and pressures, as well as high flow rates, using a minimum amount of chemical d Wallpaper and low power consumption. This is achieved by the spatial distribution of the injected chemically active substances in the volume of the combustion chamber.

Claims (1)

A device for igniting and stabilizing supersonic combustion, containing a direct-flow combustion chamber with pylons located in it, the first of which has injectors built in, connected via separate tubes to the source of chemically active additives and to the main fuel source, characterized in that the injector is built into the second pylon connected by a tube to the source of the main fuel, while a plasmatron is connected to the fragment of the combustion chamber from the outside through the plasma outlet channel.

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