Combined jet engine with compressor drive from internal combustion engine

Abstract

Combined jet engine with a compressor driven by an internal combustion engine, comprising an internal combustion engine, a control gearbox, a coupling device, an air compressor, a mixing chamber with a central body, an outlet device - jet nozzle and an automatic control system, characterized in that the air compressor (2.7 - 2.8) is driven by an internal combustion engine (1), wherein the internal combustion engine is arranged upstream of the air compressor in the direction of flow, the air compressor is single-stage and has a front power body with inlet guide vanes (2.6), wherein the rotor main bearing of the air compressor (2.7 - 2.8) with a support bearing is housed inside the body, a mixing chamber (2.11) with a central body (2.10) in the form of a profiled, perforated jacket is arranged behind the air compressor, and an uncontrolled jet nozzle is arranged behind the mixing chamber;

Description

[0001] The invention lies in the field of direct reaction engines. Despite the relatively high technical sophistication of modern aircraft engines, the task of increasing thermal efficiency has not been solved.

[0002] It is known [5; 8] that the overall efficiency of an aircraft engine ηpp is the product of the thrust efficiency η p and the thermal efficiency η t The thrust efficiency η p depends on the operating parameters of the engine as part of the propulsion system and on the flight speed. The thermal efficiency η t reflects the degree of perfection of the engine as a heat engine and indicates how much of the heat introduced into the engine with the fuel is used to perform useful work.

[0003] The degree of perfection of an engine as a heat engine can be determined by the thermal efficiency of the ideal thermodynamic cycle η realized in the engine. ti which represents the relative value of the heat used to perform useful work. The object of the invention is to determine the thermodynamic efficiency η ti by reducing heat loss due to heat entrainment in the exhaust gases.

[0004] The invention presents a combined air jet engine in which the air compressor is driven by an internal combustion engine (piston engine).

[0005] It is known [2] that patent FR 390 256 A proposes a direct reaction engine comprising an internal combustion engine as a drive group of piston pumps, each with its own combustion chamber terminating in an exhaust device. Upon rotation of the drive shaft, a fuel-air mixture is compressed in the piston, which ignites in the combustion chamber, and the hot gases and combustion products exit through the exhaust device into the atmosphere, generating the required thrust.

[0006] The main disadvantages of the aforementioned engine are: - low thermal efficiency, which means that its perfection as a heat engine is low; - high heat losses due to heat dissipation via the exhaust system of the reciprocating piston engine.

[0007] It is known [3;4] that the propulsion system of the Coanda aircraft consisted of a radial compressor, a four-stroke piston engine with 36.8 kW, an annular combustion chamber, and an exhaust system. The piston engine drives the air compressor, and the engine's exhaust gases are released into the atmosphere through the engine's exhaust system. The air compressed in the compressor was fed into the annular combustion chamber, where it was fed with fuel, which increased the temperature of the gases after combustion. After the combustion chamber, the heated gas was released into the atmosphere at a certain speed through the annular exhaust system, thus generating the thrust necessary for flight.

[0008] The main disadvantages of this drive system are: - high heat losses, since the internal energy of the exhaust gases is not used to perform useful work during the working cycle, but is dissipated through the exhaust system of the piston engine; - high heat losses in the exhaust gases of the annular exhaust system due to the low pressure drop across said exhaust system.

[0009] It is known [1] that an engine of the Campini Caproni N.1 aircraft, which includes a front air intake, a three-stage axial compressor, a liquid-cooled 12-cylinder piston engine Isotta Fraschini L.121 RC40 with a power of 662.4 kW for driving the said compressor, an air duct with a combustion chamber and an outlet device in the form of a jet nozzle with a movable central body for controlling the cross-sectional area of ​​the said nozzle. In this unit, the air flows through the front air inlet to the axial compressor. In the compressor, the air is compressed and flows through a long duct into the combustion chamber, where it mixes with the fuel. The fuel-air mixture is burned at constant pressure, and the hot gases are exhausted into the atmosphere through a nozzle with an adjustable nozzle passage, generating the thrust required for flight.

[0010] The main disadvantages of this drive system are: - high heat losses through the exhaust system of the reciprocating engine; - high total pressure losses in the intake tract due to high air resistance; - high heat losses in the exhaust system of the ring outlet due to the low pressure drop at this outlet.

[0011] It is known [6] that the I-250 and Su-5 aircraft use a combined engine consisting of a piston internal combustion engine with a propeller and an output shaft for driving an axial compressor, a compressor air intake, a combustion chamber, and an adjustable output device - a jet nozzle. This propulsion system serves to increase the speed and altitude of the aircraft. After the compressor, the air flows into the combustion chamber, where it is enriched with fuel. Part of the air behind the compressor is used to supercharge an internal combustion engine, which, among other things, drives the compressor. This propulsion system is characterized by high thrust, but also has significant disadvantages: - The propulsion system is as long as the hull and occupies the entire internal volume of the hull; - high total pressure loss in the air inlet due to the high air resistance caused by the length and complicated shape; - low compression ratio in the axial compressor and thus low thermal efficiency of the working cycle.

[0012] It is known [7] that the useful work in an internal combustion engine is generated by the combustion of fuel in compressed air and the release of heat to perform useful work during the expansion and change of the internal energy of the gas. The operating diagram of a piston engine (internal combustion engine or reciprocating piston engine) in the PV coordinates, Fig. (P - pressure, V - volume), shows that the useful work of the cycle is equal to the difference between the areas 0-1-2-2'-0'-0 and 3-2-2'-3'-3, shown in dark color. It can be seen that in a given cycle, it is impossible to use all the internal energy of the exhaust gas for useful work and that it must be transferred to the atmosphere - cooler.

[0013] It is known [9], D3: US 2012 / 0 198 814 A1. Energy conversion system with improved thermal efficiency, that the patent claims describe a method for utilising the internal energy of a gas (thermal energy + kinetic energy) which is used to cool parts of a plant or an internal combustion engine or exhaust gases which are produced during the combustion of fossil fuels such as oil, gas, petrol, paraffin, diesel, coal and the like, as well as devices for carrying out this method.

[0014] However, the method described in patent US 2012 / 0198814 A1 for transferring energy in the form of heat from one body to another has long been known, and the first and second laws of thermodynamics were formulated on its basis. (See, for example, Energy, Entropy, and Machines - An Introduction to Thermodynamics. Sanjeev Chandra, 2016, John Wiley & Sons, Ltd.; Or / end Handbook of Physics. Walter Benenson, John W. Harris, Horst Stocker, Holger Lutz, 2002 Springer-Verlag NY, Inc.).

[0015] A torque transmission from the turbine mentioned in patent US 2012 / 0198814 A1 to an internal combustion engine (see claim 7) is not sensible and is not used in industry.

[0016] It is known

[10] , D4: DE 20 2009 009 764 U1. Drive system for compressors, which is proposed as a jet engine for propelling a rocket, with an air inlet, with a turbo compressor for compressing the incoming air, with a combustion chamber for burning the fuel introduced into the compressed air, with an outlet for the combustion gases which are discharged from the combustion chamber, and with an internal combustion engine for driving a drive shaft which drives a turbo compressor, characterized in that the internal combustion engine is designed as a piston or rotary piston engine.

[0017] However, the proposed device lacks the turbo compressor claimed in position 4 of the claims.

[0018] The turbocompressor is a compressor connected directly or via a reducer to a gas turbine, from which the energy for rotation is extracted (see, for example, Advanced Gas Turbine Cycles. JH Horlock. Elsevier Science Ltd. 2003; Aircraft Propulsion. Second Edition. Saeed Farokhi. Wiley, 2014).

[0019] Patent DE 20 2009 009 764 U1 describes an internal combustion engine for driving a multi-stage axial compressor that essentially performs the function of a gas turbine. (See Jet Engines and Propulsion Systems for Engineers. Education and Educational Development and the University of Cincinnati for Human Resources Development. Edited by Thaddeus W. Fowler, Ed.D. GE Aircraft Engines. 1989).

[0020] Given that the proposed technical device is intended for installation in a jet-powered aircraft, the question arises as to the appropriateness of using such a device.

[0021] The object of the invention is to develop a combined jet engine with a compressor driven by an internal combustion engine, which makes it possible to achieve the following technical goal: to reduce the thermal efficiency of the ideal thermodynamic cycle η ti close to 1.0, thanks to the full utilization of the exhaust energy of the internal combustion engine in the working cycle of the developed power unit.

[0022] The core of the invention is a combined air jet engine with a compressor driven by an internal combustion engine, consisting of an internal combustion engine, a control gear with a clutch, an axial air compressor, a mixing chamber with a central body and an outlet device - a conical jet nozzle.

[0023] This technical result is achieved by: 1. The combined air-jet engine with compressor drive from the internal combustion engine is connected to the shaft of the driven compressor via a variable speed gearbox with a clutch device, which ensures the coordination of the torques and speeds of the drive (internal combustion engine) and the compressor rotor in all operating modes; 2. The exhaust gases of the internal combustion engine flow into the mixing chamber behind the compressor and mix with the air exiting the compressor, whereby the internal energy of the exhaust gases (pressure and temperature) is transferred to the air in the mixing chamber, thereby increasing the pressure in the mixing chamber and the temperature of the gas-air mixture; 3. The profile of the mixing chamber is formed by the outer shell of the mixing chamber and the perforated center bodies for the exhaust gas outlet, so that the pressure and temperature increase of the gas-air mixture increases evenly from the compressor outlet via the mixing chamber outlet to the inlet of the exhaust device; 4. By increasing the pressure and temperature of the gas-air mixture, the outflow velocity from the exhaust device and the thrust of the engine are increased, so that the internal energy of the exhaust gas is fully converted into usable work. This achieves the highest possible thermal efficiency of an ideal thermodynamic cycle, η ti reached.

[0024] List of figures: Fig. - Operating diagram of a piston engine Fig. - Functional diagram of a combined air jet engine; Fig. - Construction of a combined jet engine; Fig. - Operating diagram of a combined air jet engine; Fig. - Composition of the thrust module of a combined air jet engine; Fig. - Construction of a combined jet engine and air intake; Fig. - Gas flows in the thrust module of the combined air jet engine.

[0025] A schematic representation of a combined air jet engine that uses the entire internal energy of the exhaust gas is shown in Fig. The piston engine drives the compressor (axial compressor). The drive is via a variable-speed control gear with a clutch. The air for the piston engine and the axial compressor comes from the air intake. Engine operation is controlled by the automatic control system by varying the fuel supply to the internal combustion engine and the gear ratio of the control gear.

[0026] The air compressed in the axial compressor enters the mixing chamber, into which the exhaust gases from the combustion engine are also introduced. In the mixing chamber, the air mixes with the exhaust gases to form a gas-air mixture, with the pressure and temperature of the gas-air mixture increasing depending on the airflow parameters downstream of the compressor. The gas-air mixture is released from the mixing chamber into the atmosphere through the outlet device, a jet nozzle.

[0027] Compressor, mixing chamber and jet nozzle are combined to form a thrust module ( Fig. ). The structure of the jet engine is in Fig. shown, with the combustion engine drive marked as position 1 and the thrust module as position 2.

[0028] The operating diagram of the ideal cycle of the combined air jet engine in Fig. shows that by adding an air compressor and using the internal energy of the exhaust gas, thermal efficiencies η ti of almost 1.0 can be achieved. The area 0c - 1c - 4 - 5 - 0c (dark shaded) corresponds to the useful work performed by the exhaust gas in the shear modulus, since in an ideal thermodynamic process, the work expended to compress the air in the compressor is equal to the expansion work of the compressed air. The difference between the volumes of the gas-air mixture at point 5 and at point 0c at atmospheric pressure thus corresponds exactly to the exhaust volume of the internal combustion engine under the same conditions.

[0029] The structure of the aforementioned shear module is in Fig. The exhaust pipe 2.1 is located inside the drive shaft of the compressor rotor 2.3, which is mounted on the front support with a roller bearing 2.3 and on the main support 2.5 with an axial ball bearing. The bushing space at the inlet of the thrust module is enclosed by a casing tube 2.4. The compressor contains an inlet guide vane 2.6, a rotating blade disk 2.7, and a distributor 2.8. The power diaphragm 2.9, which forms the end wall of the central body 2.10 of the mixing chamber 2.11, is attached to the exhaust gas inlet line. The central body 2.10 is perforated with through holes, the density and cross-sectional area of ​​which are determined depending on the desired pressure and temperature change ratio of the gas-air mixture in the mixing chamber.

[0030] The air from the air inlet 3 ( Fig. ) flows to the combustion engine and to the inlet of the compressor of the thrust module ( Fig.The exhaust gases from the combustion engine flow through an internal pipe into the central body of the mixing chamber. Since their pressure is significantly higher than atmospheric pressure, they pass through perforations behind the compressor into the mixing chamber, where they mix with the air compressed in the compressor. The resulting gas-air mixture is released into the atmosphere via the exhaust, providing the necessary thrust.

[0031] The developed technical solution allows to achieve the declared technical result: a thermal efficiency of an ideal thermodynamic cycle η ti close to 1.0 through the complete utilization of the energy of the exhaust gases of the combustion engine in the working cycle of the engine to be developed.

[0032] Sources: 1. Alegi G. Campini Caproni. - Torino: La Bancarella AERONAUTICA, 1999. - C. 31. 2. BREVET D'INVENTION FR390256DA. OFFICE NATIONAL DE LA PROPRIÉTÉ INDUSTRIELLE. REPUBLIQUE FRANÇAISE. Système de propulsion [Text] / M. Camille - Jules - René LORIN (FR). - Application 05 / 14 / 1908; publ. 01.10.1908. 3. Gudju I., lacobescu G., lonescu O. Romanian Aeronautical Constructions 1905 - 1974. - Bucharest: Military Publisching House, 1974. - P. 385. 4. Opdycke LE French Aeroplanes before the Great War. - Atglen: Schiffer Publishing Ltd. & Design, 1999. - P. 288. - ISBN 0-7643-0752-5. 5. Willard W. Pulkrabek. Engineering Fundamentals of the Internal Combustion Engine. - New Jersey: Prentice Hall Upper Saddle River, 2002. - 426 p. 6. V. B. Shavrov. History of aircraft designs in the USSR 1938-1950. - 4th ed., corrected. - M.: Mashinostroenie, 2002. - P. 554. - ISBN 5-217-03103-4. 7. Internal combustion engines: Textbook for higher education institutions in the specialty “Construction and road machines and equipment” / Khachikyan A.S. [et al.]; edited by V.N. Lukanin. - 2nd ed., revised and enlarged. - M.: Higher school, 1985. - P-311. 8. Theory and calculation of air-breathing jet engines: Textbook for universities - 2nd edition, revised and expanded / V. M. Akimov [et al.]; edited by S. M. Shlyakhtenko. - Moscow: Mashinostroenie, 1987. - 568 p. 9. D3: US 2012 / 0 198 814 A1. Energy conversion system with improved thermal efficiency. 10. D4: DE 20 2009 009 764 U1. Antriebssystem für Kompressoren.

[0033] Abbildungen:

Claims

[1] Combined air jet engine with a compressor driven by an internal combustion engine, consisting of an internal combustion engine, variable speed gearbox, clutch device, air compressor, mixing chamber with central body, outlet device - jet nozzle and automatic control system, characterized by that the air compressor (2.7 - 2.8) is driven by an internal combustion engine (1), wherein the internal combustion engine is arranged upstream of the air compressor in the flow direction, the air compressor is single-stage and has a front power body with inlet guide vanes (2.6), wherein the rotor main bearing of the air compressor (2.7 - 2.8) is accommodated with a support bearing inside the body, a mixing chamber (2.11) with a central body (2.10) in the form of a profiled, perforated shell is attached behind the air compressor, and an unregulated jet nozzle is arranged behind the mixing chamber; [2] Combined jet engine according to claim 1, characterized by that the coupling device is combined with a variable speed gearbox and is controlled by the automatic control system already mentioned; [3] Combined jet engine according to claim 1, characterized by that the exhaust gases of the internal combustion engine are led through a gas line in the form of a round tube which opens into a conical wall into a central body provided with perforations, whereby the profile of the central body and the shape and the area of ​​the perforations in the cross-sections of the central body are selected according to the given laws of changes in temperature, pressure and flow velocity of the gas-air mixture in the mixing chamber.

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