RU2577076C2 - Low-temperature electrochemical generator - Google Patents

Abstract

FIELD: aviation.

SUBSTANCE: low-temperature plasma electrochemical generator for ignition, stabilization and optimisation of supersonic combustion chamber includes thermochemical reactor with nozzle for feeding gas with chemically active component. Thermochemical reactor is docked with supersonic combustion chamber. Generator is equipped with a plasmatron, serially connected with the thermochemical reactor.

EFFECT: invention provides reliable ignition, as well as stabilisation of combustion of hydrocarbon fuels in straight supersonic combustion chambers.

1 cl, 1 dwg

Description

The invention relates to the field of aviation technology and can be used to provide reliable ignition and stabilization of the combustion of hydrocarbon fuels in once-through supersonic combustion chambers under conditions when traditional gas-dynamic methods do not allow this (low static temperatures and pressures, lean mixtures).

Known modules for ignition and stabilization of combustion using nanosecond discharges in which the temperature of electrons can be the highest, significantly higher than the temperature of neutral molecules and ions (nonequilibrium discharges), due to which they can effectively excite high levels of molecules, the participation of which leads to intensification of chemical processes occurring during combustion, proposed in the work: Aleksandrov N., Anikin N., Bazelyan E., Zatsepin D., Starikovskaia S., Starikovskii A .. - “Chemical reactions and ignitions in hydrocarbon-air mixtures by high- voltage nanosecond gas discharge)) (AIAA Paper. 2001-2949). However, to realize nanosecond discharges, voltages of 40–50 kV are required, which are technologically difficult to apply in combustion chambers.

Known modules for igniting and stabilizing the combustion of hydrocarbon fuels that use nonequilibrium microwave and high-frequency discharges with high electron temperatures, for example, those proposed in the works: Esakov I., Grachev L., Kholftaev K. - “Investigation of under-critical microwave streamer discharge for jet engine fuel ignition ”(AIAA Paper 2001-2939) and Klimov A., Bityurin V., Brovkin V., Kuznetsov A., Sukovatkin N., Vystavkin N. -“ Plasma assisted combustion ”(Proceedings of the 3 th Workshop on Magneto-Plasma Aerodynamics in Aerospace Applications. - M .: IVTAN. 2001. p. 33-37). The disadvantage of such modules is the need to use translucent dielectric windows and coatings that break down at temperatures significantly lower than the temperature of the walls of the combustion chambers in operating modes and the specific features of the combination of electromagnetic radiation sources with cameras made of metal.

Known electrical discharge pilot flame module, which uses nonequilibrium electrode discharges that are technologically most easily implemented in combustion chambers, proposed in the work: Leonov S., Bityurin V., Savelkin K., Yarantsev D. - “Plasma-induced ignition and plasma assisted combustion of fuel in high speed flow ”(Proceedings of 5 th Workshop" PA and MHD in Aerospace Applications ". - M .: IVTAN. 2003, p. 56).

The disadvantage of this module is that the ignition zone is formed on the periphery of the combustion chamber, near its wall, and the need to use a ledge, in the recirculation region behind which a zone of plasma-chemical reactions is created, leads to an increase in aerodynamic resistance to the flow in the combustion chamber.

The closest technical solution is a supersonic plasma-chemical combustion stabilizer for a direct-flow combustion chamber (RF patent No. 2499193), which is taken as a prototype by the maximum number of similar essential features. The known combustion stabilizer contains a thermochemical reactor (TXR) in one of two consecutively located downstream electrodes of the anode and cathode, made in the form of streamlined pylons with symmetrical aerodynamic profiles and installed in the flow part of the combustion chamber, while the anode is electrically isolated from the metal wall of the combustion chamber, and the cathode is located in the wake of the anode and is mounted directly on the chamber wall. The anode has a kink and consists of two sections: the root, with a negative sweep relative to the direction of flow, and the end, with zero sweep, providing gas-dynamic stabilization of the position of the discharge channel and the intensification of plasma-chemical reactions that occur in the zone of low pressure behind the zero sweep profile. To inject fuel into the stream, injectors are placed on the streamlined surface of the anode (pylon), to which fuel is supplied through a supply tube built into the pylon. The disadvantage of the prototype is the increased level of aerodynamic losses due to the difficulty of moving the anode end of the discharge channel from the breakdown point to the zone of low pressure at the trailing edge of the anode. Breakdown occurs on the nearest metal wall of the chamber.

The objective and technical result of the invention is to provide a low level of energy costs with a significant impact, allowing ignition and maintaining stable combustion of the fuel-air mixture on processes in the volume of the combustion chamber, as well as controlling the energy efficiency of fuel combustion to achieve the functioning of energy-driven installations of supersonic aircraft in the required range of flight conditions.

The problem to which the claimed invention is directed, and the technical result obtained by implementing it, is to optimize the internal chamber processes and characteristics and can be achieved by a combination of the claimed essential features necessary and sufficient for the implementation of the technical result.

The essence is illustrated by the drawing, which shows a diagram of the claimed electrochemical generator of low-temperature plasma, where:

1 - thermochemical reactor;

2 - a combustion chamber;

3 - plasmatron case (anode);

4 - cathode;

5 - plasmatron;

6 - fitting for supplying a gaseous working fluid of the plasmatron;

7 - ceramic holder;

8 - metal holder clip;

9 - cathode electrode;

10 - diffuser;

11 - insulated nozzle;

12 - a small dielectric tube;

13 - a large dielectric tube;

14 - gas supply fitting with a chemically active component;

15 - tube-swirl;

16 - centering insert.

The essence of the proposed technical solution is that, like the prototype, it contains a thermochemical reactor 1, a combustion chamber 2, anode 3, cathode 4.

In contrast to the prototype, a plasmatron 5 connected with a thermochemical reactor 1, which is connected to the combustion chamber 2, was additionally introduced. The plasmatron housing 5 with a nozzle 6 is an anode 3. The ceramic holder 7 of the electrode 9 of the cathode 4, mounted in a metal shell 8, insulates the electrode 9 of the cathode 4 from the plasmatron body 5. The diffuser 10 and the nozzle 11 are located on the dielectric inserts in the form of tubes 12 and 13. Gas with a chemically active component is supplied to the thermochemical reactor 1 through the nozzle 14. Low temperature plasma is blown through the nozzle 11 in the direction of the anode 3 and then of the thermochemical reactor 1. The anode 3 is made of a high-temperature material or a material with high thermal conductivity. In the anode 3 there is an axial hole for blowing plasma into the swirl tube 15. The swirl tube 15 is connected to a graphite centering insert 16.

The device operates as follows.

The plasma is introduced into the combustion chamber 2. The introduced plasma has a diffuse character due to its formation in the plasmatron 5. This makes it possible to affect a larger volume of the fuel-air mixture inside the combustion chamber 2. Both electric and chemical energy are used, and the main power is allocated precisely for due to the use of the chemical component, which is more effective from the point of view of technical implementation, as electric power may not be enough on board an aircraft for a significant impact on the in-chamber processes of an energy propulsion system. The electrode 9 of the cathode 4 is supplied with power from a source with an arc ignition circuit. The electrode 9 is isolated from the body of the plasmatron 5, which plays the role of the anode 3, with a ceramic holder 7, mounted in a metal casing 8. Between the cathode 4 and the body of the plasmatron 5, an independent electric discharge occurs in the medium of the working fluid through the isolated nozzle 11. The gaseous working fluid is supplied through the nozzle 6 to the plasmatron body 5. Next, the gaseous working fluid through leaks enters the large dielectric tube 13 to the ceramic tangential diffuser 10, due to the passage of gas through which the gas-dynamic twisting of the anode contact spot of the arc with the plasmatron body 5 to reduce erosion with on the one hand, and stabilization of the arc on the channel axis of the plasmatron 5 on the other hand. The nozzle 11 is isolated from the cathode 4 by a diffuser 10, and from the anode small 12 and large 13 by dielectric tubes. The low-temperature plasma of the working fluid is fed through a hole in the end face of the plasmatron body 5 to the thermochemical reactor 1, which is aligned coaxially with the plasmatron 5. The plasma through the graphite centering insert 16 enters the swirl tube 15. The insert 16 and tube 15 are located inside the thermochemical reactor 1, into which through the fitting 14 is supplied gas with a chemically active component. Gas passing through the tangential openings in the wall and leaks at the ends of the tube-swirler 15 cools it and reacts with the plasma. In the swirl tube 15, mixing and reaction between the plasma and the gas with the chemically active component takes place. Tube 15 experiences high thermal loads. Their significant reduction is achieved due to the supply of plasma along the axis of the tube 15 and the supply of gas with a chemically active component along the inner wall through a series of holes located tangentially to the plasma flow. In this case, a partial veil of convective heat transfer from the plasma flow to the quartz tube occurs, as well as cooling due to blowing with a gas with a chemically active component. For more efficient optimization of intracameral processes, the supply of low-temperature plasma to combustion chamber 2 can be carried out by simultaneously connecting several electrochemical generators of low-temperature plasma.

The thermochemical reactor 1 is connected to the combustion chamber 2. The low-temperature plasma with the generated radicals for initiating and maintaining combustion enters the combustion chamber 2 of the propulsion system.

The performed simulation confirmed the possibility of igniting the fuel in the channel of the combustion chamber 2 and maintaining the flame in the vicinity of the injection zone (due to several local effects of injected plasma jets with a temperature of more than 3000 K and with a mass velocity of 500 m / s) under conditions when traditional gas-dynamic methods do not allow this to be done. Thus, the technical result of the invention is to provide a low level of energy costs when obtaining a significant impact on the processes in a supersonic combustion chamber of an aircraft engine power plant for efficient ignition, stabilization and optimization of combustion.

Claims (1)

An electrochemical generator of a low-temperature plasma containing a thermochemical reactor that interfaces with a supersonic combustion chamber, an anode and a cathode, characterized in that the generator is equipped with a plasmatron in series with which a thermochemical reactor is connected, while the plasmatron body with a fitting for supplying a gaseous working fluid is an anode, through a ceramic holder in a metal holder introduced the cathode electrode, and the cathode through a diffuser is connected to an insulated nozzle fixed in the plasmatron housing through small and large dielectric tubes, and at the end of the plasmatron body there is a channel for supplying plasma to a thermochemical reactor having a fitting for supplying gas with a chemically active component, a high-temperature swirl tube with holes is installed inside the thermochemical reactor body, which is held on the axis of the thermochemical centering reactor insertion.

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