RU2145039C1 - Method and device for fuel feed to thermal engine chamber - Google Patents

Abstract

FIELD: cooling of the mixing head of the thermal engine combustion chamber. SUBSTANCE: the method consists in fuel feed to the duct at an angle to its axis. First fuel is fed to the cooling circuit of the thermal engine chamber, and then it is successively fed to the cooling jackets of the funnel, duct cylindrical part, manifold and fuel pipe-line, and further to the accumulator-heat exchanger, where it is heated and in a gaseous state through the inner cavities of the pipe-line, manifold and through the holes in the funnel walls is fed first to the duct, and then to the engine chamber. The device has a casing with a duct with radial holes in the walls for fuel feed, and the duct cylindrical part changes into a taper funnel connected to the engine chamber. Holes for fuel feed to the duct are made perpendicularly to the funnel generating lines, the duct cylindrical part section and the funnel are embraced by the fuel manifold with the pipe-line, which is connected to the heat exchanger. The engine cooling circuit and the cooling jackets of the funnel, cylindrical part of the oxidizer duct, manifold and fuel pipe-line are successively connected to one another and to the heat exchanger. EFFECT: enhanced efficiency of cooling of the thermal engine head both in operation without after-burning when one fuel is fed, and in operation with after-burning, when two fuel components are fed. 3 cl, 1 dwg

Description

 The invention relates to engine building, in particular, can be used to supply gaseous fuel heated to a temperature above the heat resistance limits of the applied structural materials, for example, stainless steel and nickel alloys, to the mixing device of a heat engine.

Known combustion chamber rocket engines, the operability of the inner walls of which when exposed to high temperatures is provided using external and (or) internal cooling. In a similar way, the nozzle and the firing bottom of the mixing head can be cooled [1]. The organization of special cooling of the mixing elements and the internal cavities of the mixing heads of the rocket engine was not previously used, because the temperature of the fuel components during LRE operation, even according to the scheme with generator gas afterburning, is usually not more than 800 ^o C, which does not exceed the heat resistance limit of the applied structural materials.

Cooled mixing elements for supplying fuel to a high-temperature air stream are used in the WFD, especially when flying at high speeds in dense atmospheric layers. In particular, cooled mixing elements are known for supplying liquid fuel to a high temperature gas stream. In the mixing element of the first type, cooling is performed due to the porous structure of the wall of the element located in the air stream. In the mixing element of the second type, a cooling film is formed on its surface when fuel is supplied through holes with a diameter of 0.2 ... 2 mm in the wall, located at an angle of 10 ... 30 ^o to the surface of the element [2].

 The disadvantages of this design is the presence of energy associated with the creation of a cooling film, fuel loss. In addition, the manufacture of a porous wall or holes of small diameter at small angles to the surface can cause technological difficulties, especially for small products. In this case, resizing within manufacturing tolerances can lead to significant non-uniformity of the cooling film and, consequently, instability of the cooling structure.

 There are various fuel supply devices used in the chemical and gas industry, the design of which is cooled using water flowing through the cooling path. For example, block nozzles are known for gasifying liquid fuel, in particular fuel oil, miscible with water vapor and oxygen, followed by feeding them through cone-shaped bells with tangential openings into the combustion zone. To protect the mixing elements and the oxygen cavity from the heat flux, flow cooling of the cylindrical and end surfaces of the burner with water is used [3].

 Known multi-nozzle sectional burner for producing process gas under pressure. In this case, fuel (hydrocarbon gas and oxygen) is supplied to the reactor through coaxial pipes: gas passes through the external channel, oxygen through the middle channel, and cooling water circulates through the central channels [4].

 Known multi-nozzle burner for the partial oxidation of liquid fuels (gaseous, liquid and mixtures thereof) in an oxygen environment. Fuel is fed into the combustion zone through a central pipe and through a tube sheet enters two-component nozzles. An oxidizing agent (or oxygen-containing vapor) is supplied to the nozzles through an annular space defined by a housing and fuel pipes. To protect the cylindrical and end (with fuel nozzles) surfaces of the burner body from heat flow from the combustion zone, a water-cooled shirt is used [5].

 The disadvantages of the presented designs is a significant overheating of their end surfaces during operation, leading to the appearance of microcracks at the junction of the nozzles with the bottom, burning oxygen nozzles and disruption of the burners.

 Known gas burner used in the chemical industry, for example for the breakdown of natural gas with oxygen and steam. Oxygen passes through the central pipe and through pipes fixed in the base plate is supplied to the combustion zone. Steam is fed through the annular gap between the oxidizer pipe and the fuel cavity into the collector through which the oxidizer pipes pass, and then through the steam pipes, coaxial pipes of the oxidizer, is fed into the combustion zone. Combustible gas is fed into the combustion zone through an annular gap between the housing with the distribution grid fixed to it and steam pipes. To protect the cylindrical surface of the burner from the effects of thermal radiation, a water-cooled shirt is used [6]. The end surface of the burner with the oxygen and steam pipes leaving it does not cool, which leads to their overheating during operation and failure.

 A fuel supply device without prior mixing is known, in which fuel is supplied to the combustion zone through a central pipe, the oxidizer through an annular passage, coaxial to the central pipe, and then through channels to the oxidizer nozzles located in circles around the outlet of the central pipe. The cooling fluid passes through the annular channels coaxial with the central tube: the inner one, located between the central tube and the annular passage of the oxidizer (towards the end surface of the burner), and the outer one, located between the passage of the oxidizer and the outer wall of the casing (from the end surface of the burner to the outlet). The channels for the passage of coolant are interconnected by grooves running parallel to the end surface of the burner between the oxidizer nozzles [7].

 During the operation of the device, cases of overheating of the massive front wall of the burner caused by insufficient cooling were observed.

Known burner for the partial oxidation of gaseous hydrocarbons in gases containing CO and H ₂ , operating as follows. Combustible gases pass through a central pipe ending with a distributor with a tube sheet, and then through pipes fixed at the base of the burner, they are fed into the reaction zone. The oxidizing agent passes through the annular gap between the casing and the water cavity used to cool the burner, and through the oxidizing pipes fixed at one end in the casing bottom and the other at the base of the burner, is fed into the reaction zone. The cooling water passes through the annular gap between the fuel pipes and the oxidizer cavity through a pipe plate with water pipes fixed to it, aligned with the fuel pipes, cools the base of the burner and goes to the outlet through the outer jacket [8].

 However, the workflow in the above inventions [3-8] proceeds at a significantly lower level of temperatures and pressures than is required for the operation of heat engines, in particular LRE. The level of overall and mass characteristics, as well as the use of water as a cooler, does not satisfy the requirements for products installed on aircraft.

 As a prototype of the invention adopted jet-jet gas-liquid nozzle liquid propellant rocket engine and the method of its operation. The nozzle consists of a tubular body with a channel into which a gaseous oxidizing agent can be supplied. Radial openings are made in the walls of the channel at an angle to the gas stream for injection into the liquid fuel stream. In the channel behind the fuel openings, when an oxidizing agent is introduced into it, a mixing section is formed on which the fuel components are sprayed and mixed, and mixture burning can occur immediately after the fuel jets, as evidenced by the often observed discolouration colors on the walls of the housing behind the fuel openings [9].

 The technical problem solved by the claimed group of inventions is the development for heat engines, in particular for LRE, the design of a cooled fuel supply device, the temperature of which exceeds the heat resistance limits of stainless steel and nickel alloys, usually used as structural materials in LRE as on non-afterburning mode, when one fuel is supplied, as well as in the afterburning mode, when two components of the fuel are supplied - the oxidizing agent and the fuel.

 This problem is solved by the fact that in the method of operation of the device for supplying fuel to the heat engine chamber, which consists in supplying fuel into it, radially at an angle to the axis of the channel, according to the invention, the fuel is first fed to the cooling path of the heat engine chamber, and then sequentially sent to the bell cooling jackets , the cylindrical part of the channel, manifold and fuel pipe. After that, the fuel enters the accumulator-heat exchanger, where it is heated to a high temperature and in a gaseous state through the internal cavity of the pipeline, the collector and through the holes in the walls of the socket, first fed into the channel and then into the chamber of the heat engine.

 The proposed method of operation is realized in that in the fuel supply device to the heat engine chamber, comprising a housing with a channel, radial openings for supplying fuel are made in the walls of which at an angle to the axis of the channel, the cylindrical part of the channel passes into a conical socket connected to the heat engine chamber. The holes for supplying fuel to the channel are made perpendicular to the socket forming a bell, a portion of the cylindrical part of this channel and the socket are covered by a fuel manifold with a pipeline. The pipe is connected to a heat exchanger battery. The cooling path of the heat engine chamber and the cooling jacket of the bell, the cylindrical part of the oxidizer channel, the manifold, and the fuel pipe are connected in series with each other and the battery-heat exchanger.

 In the event that the temperature of one or more fuel components is so high that only regenerative cooling of structural elements is not enough, the inner walls of the manifold and the fuel pipe can be made of heat-resistant structural material, such as molybdenum.

 The proposed device can operate both in the afterburning mode (fuel and oxidizer are supplied), and in the non-afterburning mode (one fuel is supplied).

To ensure optimal mixing of the fuel and the oxidizing agent in the afterburning mode, the ratio of the geometric dimensions of the diameter of the chamber (D _to ) and the diameter of the opening of the fuel supply (d _g ) is determined by the formula:
D _c / d _g = 4.76 (ρ _g W $\genfrac{}{}{0ex}{}{\text{2}}{\text{g}}$ / ρ _o W $\genfrac{}{}{0ex}{}{\text{2}}{\text{o}}$ -0.2) ^0.35 ,
where ρ _g , ρ _o - respectively, the density of the fuel and the oxidizing agent in the place of interaction of the jets of fuel components;
W _g , W _about - respectively, the speed of the fuel and the oxidizing agent at the site of interaction of the jets of the fuel components.

 The drawing shows a diagram of a cooled device for supplying fuel components to the chamber of a heat engine.

 The device consists of a housing with a channel 1, into which an oxidizing agent can be supplied, the cylindrical part of the channel passes into a conical socket 2, the perpendicular to which there are openings 3 for supplying fuel to the channel. The cylindrical part of the channel and the bell have inner and outer walls forming cooling jackets of the channel and the bell 4, 5, respectively. The inner and outer walls of the bell are connected respectively to the inner wall 6 and the outer wall 7 of the combustion chamber 8. The walls 6 and 7 form the cooling path of the chamber 9. On the outer walls of the bell and the section of the cylindrical part of the channel, a collector 10 for supplying heated fuel with a pipe 11 is fixed. The collector and the pipeline has double walls between which cooling jackets 12 and 13 are located. The channel 1 is equipped with a leveling grid 14 and is connected to the oxidizer feed pipe 15 using an adapter 16.

 The feed device operates as follows. Fuel, such as hydrogen, passes through the cooling path 9 of the chamber 8, the cooling jacket of the socket 5, the section of the cylindrical part of the channel 4, the manifold 12 and the fuel pipe 13, respectively, and enters the battery-heat exchanger 17, where it is heated using an external heat source, for example, solar energy to high temperature. Then the heated fuel through the internal cavity of the pipe 11, the collector 10 and the holes 3 located on the conical socket 2, is fed into the channel, and then into the chamber 8 of the heat engine. Thus, the operating mode of the engine without afterburning is realized.

 The proposed device can also work in the afterburning mode, while an oxidizing agent, for example, oxygen, enters the chamber 8 through the channel 1 with the leveling grating 14 and the conical bell 2, and the fuel enters the engine chamber in the above manner. During the interaction of the fuel jets with the oxidizer stream, the fuel components are mixed and the mixture self-ignites due to its high mass-average temperature. After the expiration of the combustion products from the heat engine chamber, the afterburning mode is implemented.

 The use of gaseous fuel heated to a high temperature by an external energy source can significantly increase the specific impulse of engine thrust. So, the use of hydrogen heated to a high temperature, for example, up to 2000 ... 2200K, as a fuel, in units of a power plant, will increase the specific thrust of the chamber by about 20% compared to a hydrogen-oxygen engine without heating it from an external source of energy.

 Using the fundamental provisions of the invention, a combustion chamber was designed, structurally designed and manufactured that successfully passed fire tests with confirmation of operability and high energy performance.

Sources of information
1. Sinyarev G.B., Dobrovolsky M.V. Liquid rocket engines. M .: Oborongiz, 1955.p. 261, 272, 291, FIG. 86, 91, 104.

 2. US patent N 3699773, MKI class. F 02 G 1/00; NKI class 60-39.74 R, 1972.

 3. Copyright certificate of the USSR N 186065, cl. F 23 D 11/12, 1966.

 4. Copyright certificate of the USSR N 330306, cl. F 23 D 14/32, 1972.

 5. Patent GDR N 146765, cl. F 23 D 17/00, 1981.

 6. Patent GDR N 214912, CL F 23 D 15/00, 1984.

 7. Patent EPO N 0151683, cl. F 23 D 14/78, 1989.

 8. The patent of Germany N 3726875, cl. F 23 D 14/78, 1989.

 9. Andreev A.V., Bazarov V.G., Grigoriev S.S., Dushkin A.L., Lyulka L.A. Dynamics of gas-liquid nozzles, Moscow: Mashinostroenie, 1991.p.5. fig. 1.1.

Claims (3)

 1. The method of supplying fuel into the chamber of a heat engine, which consists in supplying fuel to the channel at an angle to its axis, characterized in that the fuel is sequentially directed to the cooling path of the heat engine chamber, to the cooling cools of the socket, of the cylindrical part of the channel, manifold, pipeline and a heat exchanger accumulator, where it is heated to a high temperature and in a gaseous state through the internal cavities of the pipeline and collector and through openings in the walls of the socket, is fed into the channel, and then into the heat engine chamber la.  2. A device for supplying fuel to the chamber of a heat engine, comprising a housing with a channel, in the walls of which holes for supplying fuel are made at an angle to the axis of the channel, characterized in that the cylindrical part of the channel passes into a conical socket connected to the chamber of the heat engine perpendicular to the socket holes are made for supplying fuel to the channel, a section of the cylindrical part of this channel and the bell are covered by a fuel collector with a pipeline connected to the battery-heat exchanger, while kt cooling chamber of the heat engine and the cooling jacket of the socket and the cylindrical portion of the channel and the reservoir conduit and fuel and interconnected with the accumulator-heat exchanger sequentially.  3. The device according to claim 2, characterized in that the inner walls of the collector with the pipeline are made of heat-resistant material, such as molybdenum.