Small valveless pulsating jet engine

Abstract

The invention discloses a small valveless pulsating jet engine which comprises a combustion chamber, an air inlet, a resonance tube, an exhaust nozzle and a rectifying ring. The rear end face of the combustion chamber is connected with air inlets and resonant tubes; the outlet direction of the air inlet faces behind the engine; the front end of the resonance tube is connected with the combustion chamber; and the rectifying ring is mounted at a nozzle of the exhaust nozzle. The pulsating jet engine is simple in structure, free of movable parts, stable in work in the flying process and high in thrust efficiency.

Description

Technical Field

[0001] This invention belongs to the field of aircraft technology, specifically relating to a small valveless pulse jet engine. Background Technology

[0002] Small valveless pulse jet engines are a type of power plant within the jet engine category. Currently, publicly available pulse jet engines, both domestically and internationally, primarily use valves or diaphragms to control the combustion chamber intake. The use of moving parts like valves significantly reduces engine lifespan and reliability, and also lacks the capability for long-term storage and maintenance-free operation. Therefore, the design of small valveless pulse jet engines must prioritize simple structure and ease of use and maintenance.

[0003] The small valveless pulse jet engine is a new engine structure currently under research. Based on the combustion principle and operating characteristics of pulse engines, after pulse combustion, the lengths of the air inlet and the tailpipe are different, resulting in different air flow rates and durations. At the same time, the hot gas in the tailpipe is not completely ejected and flows back to the engine combustion chamber for secondary combustion.

[0004] Currently available reports do not include flight performance studies of small valveless pulse jet engines. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this invention provides a small valveless pulse jet engine, comprising a combustion chamber, an air inlet, a resonator, a tail nozzle, and a rectifier ring; the rear end face of the combustion chamber is connected to the air inlet and the resonator; the air inlet outlet faces the rear of the engine; the front end of the resonator is connected to the combustion chamber, and the rear end is connected to the tail nozzle; the rectifier ring is installed at the tail nozzle nozzle. This invention's pulse jet engine has a simple structure, no moving parts, stable operation during flight, and high thrust efficiency.

[0006] The technical solution adopted by this invention to solve its technical problem is as follows: A small valveless pulse jet engine includes a combustion chamber, an air inlet, a resonator, a tailpipe, and a fairing ring. The rear end face of the combustion chamber is connected to the air intake and the resonant tube; The air intake outlet faces the rear of the engine; The front end of the resonant tube is connected to the combustion chamber, and the rear end is connected to the tail nozzle. The rectifier ring is installed at the nozzle of the tailpipe.

[0007] Preferably, the lengths of the air inlet and the tailpipe flow channel are different.

[0008] Preferably, the valveless pulse jet engine further includes an igniter; the igniter can be installed at any position on the combustion chamber wall.

[0009] Preferably, the valveless pulse jet engine further includes an injection port; the injection port is disposed inside the air intake of the valveless pulse jet engine.

[0010] Preferably, the diameter of the air inlet is 0.48 times the diameter of the combustion chamber; the diameter of the resonant tube is 0.5 times the diameter of the combustion chamber; the diameter of the tail nozzle is 1 to 1.1 times the diameter of the combustion chamber; the length of the air inlet is 2 times the length of the combustion chamber; and the total length of the tail nozzle is 12 times the diameter of the tail nozzle.

[0011] Preferably, the valveless pulse jet engine structure is constructed from thin-walled steel plates welded together.

[0012] Preferably, the tail nozzle has an expanding section structure, with the outlet portion including a cylindrical section; the expansion angle of the tail nozzle is between 1.5° and 3°.

[0013] Preferably, the air inlet structure is in the form of a cylindrical section; the inlet portion of the air inlet is a circular annular air inlet lip or an elliptical annular air inlet lip.

[0014] Preferably, the rectifier ring is fan-shaped, arc-shaped, or ring-shaped.

[0015] Preferably, the air inlet and the tail nozzle are in single or multiple parallel configurations.

[0016] The beneficial effects of this invention are as follows: This invention utilizes the structural proportions of the combustion chamber, air intake, resonant tube, and exhaust nozzle to generate stable pulsating combustion, producing a certain amount of thrust. This engine features a simple structure, convenient use and maintenance, high overload resistance, long storage life, and maintenance-free operation. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a valveless pulsating jet engine with a single air inlet and a single nozzle according to an embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram of a valveless pulsating jet engine with dual air inlets and a single nozzle, according to an embodiment of the present invention.

[0019] Figure 3 This is a schematic diagram of a valveless pulsating jet engine with dual air inlets and dual nozzles according to an embodiment of the present invention.

[0020] Reference numerals: 1-Combustion chamber; 2-Air inlet; 3-Resonator tube; 4-Tail nozzle; 5-Rectifier ring. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] To simplify the structure of valved pulse jet engines, this invention provides a novel valveless pulse jet engine that utilizes the combustion mechanism and operating characteristics of pulse jet engines. It reduces the number of intake valves, designs a pneumatic intake port, and effectively solves the problems of engine intake and adaptive ignition by utilizing the length difference between the intake port and the tail nozzle. This makes the structure of the pulse jet engine simpler and its operation more stable and reliable.

[0023] A small valveless pulse jet engine includes a combustion chamber, an air inlet, a resonator, a tailpipe, and a flow straightener. The combustion chamber is the main component of the engine, and its rear end is connected to the air inlet and the resonator. The air inlet faces the rear of the engine. The front end of the resonator is connected to the combustion chamber, and its rear end is connected to the tailpipe. The flow straightener is installed at the nozzle of the tailpipe.

[0024] The valveless pulse jet engine is constructed entirely of thin-walled steel plates welded together.

[0025] Valveless pulse jet engines utilize the different lengths of the air intake and exhaust nozzle to vary the amount of air drawn in for pulsed combustion. Furthermore, a portion of the hot combustion gases in the exhaust nozzle are retained and returned to the engine combustion chamber to ignite a new air-fuel mixture for the next cycle, thus enabling the engine to adapt to combustion.

[0026] For a valveless pulse jet engine to operate normally, it also requires an igniter and a fuel injector. The igniter can be installed anywhere on the wall of the pulse jet combustion chamber, and its output should have a certain temperature and energy. The fuel injector is located inside the engine's air intake and has the ability to mix with fresh air.

[0027] Based on the structural characteristics of valveless pulsating engines, to achieve stable pulsating combustion, the engine's combustion chamber, intake, resonator, and exhaust nozzle must have specific proportional relationships, such as cross-sectional dimensions and length proportions. Different proportional relationships will result in different thrust.

[0028] The diameter of the air intake is approximately 0.48 times the diameter of the combustion chamber, the diameter of the resonator tube is approximately 0.5 times the diameter of the combustion chamber, and the diameter of the tailpipe nozzle is 1 to 1.1 times the diameter of the combustion chamber. The length of the air intake is approximately twice the length of the combustion chamber, and the total length of the tailpipe is approximately 12 times its diameter.

[0029] The intake and exhaust nozzle of a valveless pulse jet engine have different lengths. This different ratio allows the intake and exhaust nozzle to be designed as a single unit or multiple units connected in parallel.

[0030] Example: Reference Figure 1 and Figure 2This invention designs a small valveless pulse jet engine with a diameter of 80mm-90mm and a total length of 800mm-900mm. The layout of the combustion chamber, air intake, resonator pipe and tail nozzle is shown in the figure. Figure 1 It uses a single air inlet and consists of two drawings: a front view and a top view. Figure 2 It employs two parallel air intakes. The engine produces an average thrust between 30N and 70N.

[0031] Reference Figure 3 A valveless pulsed jet engine with a parallel air intake and a parallel tailpipe structure was designed, with an engine diameter of 150mm-300mm and a total length of 900mm-1200m. The engine produces an average thrust between 50N and 500N.

[0032] Compared with existing valved pulse jet engine structures, this invention features simple structure, convenient use and maintenance, resistance to high overload, and long-term storage capability. Furthermore, in loitering munition applications, it demonstrates the ability to reliably operate and generate stable thrust under varying altitudes and flight speeds.

[0033] The valveless pulse jet engine of this invention simplifies the structure of valved pulse jet engines. The valveless pulse jet engine is simple and convenient to use and maintain, has a long service life, and produces stable and reliable thrust, especially demonstrating its reliability during flight.

Claims

1. A small valveless pulse jet engine, characterized in that, This includes the combustion chamber, air intake, resonator, exhaust nozzle, and fairing ring; The rear end face of the combustion chamber is connected to the air intake and the resonant tube; The air intake outlet faces the rear of the engine; The front end of the resonant tube is connected to the combustion chamber, and the rear end is connected to the tail nozzle. The rectifier ring is installed at the nozzle of the tailpipe.

2. A small valveless pulse jet engine according to claim 1, characterized in that, The air inlet and tail nozzle have different flow channel lengths.

3. A small valveless pulse jet engine according to claim 1, characterized in that, The valveless pulse jet engine also includes an igniter; the igniter can be installed at any position on the combustion chamber wall.

4. A small valveless pulse jet engine according to claim 1, characterized in that, The valveless pulse jet engine also includes an injection port; the injection port is located inside the air intake of the valveless pulse jet engine.

5. A small valveless pulse jet engine according to claim 1, characterized in that, The diameter of the air inlet is 0.48 times the diameter of the combustion chamber; the diameter of the resonant tube is 0.5 times the diameter of the combustion chamber; the nozzle diameter of the tailpipe is 1 to 1.1 times the diameter of the combustion chamber; the length of the air inlet is 2 times the length of the combustion chamber; and the total length of the tailpipe is 12 times the diameter of the tailpipe.

6. A small valveless pulse jet engine according to claim 1, characterized in that, The valveless pulse jet engine is constructed from thin-walled welded steel plates.

7. A small valveless pulse jet engine according to claim 1, characterized in that, The tail nozzle has an expanding section structure, with the exit portion including a cylindrical section; the expansion angle of the tail nozzle is between 1.5° and 3°.

8. A small valveless pulse jet engine according to claim 1, characterized in that, The air inlet has a cylindrical section structure; the inlet portion of the air inlet is a circular or elliptical annular air inlet lip.

9. A small valveless pulse jet engine according to claim 1, characterized in that, The rectifier ring can be fan-shaped, arc-shaped, or ring-shaped.

10. A small valveless pulse jet engine according to claim 1, characterized in that, The air inlet and tail nozzle can be a single unit or multiple units connected in parallel.

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