A high combustion efficiency grain water ram test engine

Abstract

This invention discloses a high-efficiency propellant-type water ramming test engine, comprising a front end cap, an outer cylinder, a rear end cap, a combustion chamber, and a nozzle connected in sequence, as well as an inner cylinder, an injection element, a piston, and a propellant grain. The front end cap serves as an air intake channel; the outer cylinder has a water inlet, forming a sandwich between the outer and inner cylinders; the rear end of the inner cylinder has a circular hole that forms a water flow channel with the injection element, and the interior of the inner cylinder forms a combustion chamber; the front end of the piston contacts the filling gas, and the rear end is in close contact with the propellant grain; the injection element sandwich forms a water flow channel, and a small circular hole on the injection element allows water to be injected into the combustion chamber; the propellant grain is a metal-rich fuel propellant, and during combustion, water in the propellant reacts with the metal to release energy through a chemical reaction. During operation, the propellant grain gradually burns and recedes, while the filling gas pushes the piston through the air intake channel to maintain an optimal constant distance between the propellant grain combustion surface and the water nozzle, ensuring that the combustion efficiency remains at its highest level.

Description

Technical Field

[0001] This invention belongs to the field of underwater propulsion technology and relates to a high-efficiency propellant-type water ramming test engine. Background Technology

[0002] In the mid-to-late 20th century, countries such as Russia and the United States proposed a new type of underwater propulsion device—the water ramjet engine—that uses water as an oxidizer in the underwater vehicle's operating environment and carries only high-energy metallic fuel. According to reports, underwater weapons such as torpedoes employing water ramjet engine technology and supercavitation technology combine high-speed penetration, high-speed attack, and high accuracy, resulting in a significant leap in their combat performance.

[0003] A water ramjet engine mainly consists of an inlet pipe, a water nozzle, a combustion chamber, a tailpipe, and fuel. The fuel can be divided into two types: pure water-reacting metal powder and water-rich reactive metal powder composite solid propellant grains. Therefore, water ramjet engines can be classified into powder water ramjet engines and propellant grain-type water ramjet engines. Propellant grain-type water ramjet engines have gained widespread attention due to their advantages such as simple structure, fast system start-up response, high reliability, and convenient use and maintenance. However, during engine operation, the propellant grain combustion surface gradually recedes away from the water nozzle, making it difficult to ensure sufficient mixing and reaction between the metal fuel and water, thus hindering the maintenance of high combustion efficiency and affecting the engine's specific impulse performance. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a high-efficiency propellant-type water ramjet test engine, solving the problems of existing propellant-type water ramjet engines where the propellant propellant gradually moves away from the water nozzle during operation, failing to ensure sufficient mixing and reaction between the metal fuel and water, making it difficult to maintain high-efficiency combustion, and affecting the engine's specific impulse performance.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A high-efficiency propellant-type water ramming test engine includes a front end cap, an outer cylinder, an inner cylinder, a piston, a propellant grain, an injection nozzle, a rear end cap, a combustion chamber, and a nozzle; the front end cap, outer cylinder, rear end cap, combustion chamber, and nozzle are connected in sequence; the inner cylinder is located inside the outer cylinder, the piston and propellant grain are located inside the inner cylinder and are in close contact with the inner wall of the inner cylinder, and the annular injection nozzle is located at the rear end of the inner cylinder;

[0007] The front end of the front end cap can be connected to an external gas source, and the rear end face of the front end cap is in contact with the front end face of the inner cylinder. The front and rear ends of the inner cylinder are sealed by sealing rings, forming a water flow interlayer between the inner cylinder and the outer cylinder. The outer cylinder has multiple water inlets, and external water can enter the water flow interlayer through the water inlets. The rear part of the inner cylinder has multiple circular holes arranged circumferentially and corresponding to the injection component to form a water flow channel. The front and rear ends of the injection component are sealed by sealing rings, and its side wall has multiple small circular holes circumferentially. The water entering the water flow interlayer can be injected into the combustion chamber inside the inner cylinder 3 in sequence through the circular holes, water flow channel and small circular holes. The front end of the piston can contact the gas filled by the front end cap interface, and the rear end is tightly bonded to the propellant grain coating layer.

[0008] The present invention also includes the following technical features:

[0009] Specifically, the piston consists of two parts: the front end is made of heat-insulating material and the rear end is made of high-temperature resistant ceramic composite material. The two parts are tightly bonded together with an adhesive to form a whole.

[0010] Specifically, the propellant grain is a water-rich reactive metal fuel propellant, including a composite solid propellant rich in Al, Mg, and Li metal powders.

[0011] Specifically, the propellant grain has a coating layer on its front end face and side wall, so that the combustion surface of the propellant grain is only on the rear end face.

[0012] Specifically, the front end cap is threaded to the front end of the outer cylinder; the rear end cap is threaded to the rear end of the outer cylinder, and its front end face is in contact with the end face of the injection component; the afterburning chamber is threaded to the rear end cap; and the nozzle is threaded to the afterburning chamber.

[0013] Specifically, the nozzle consists of a converging section, a throat, and a diverging section from front to back. The converging section is connected to the afterburner chamber via a thread, and the diverging section is connected to the outside.

[0014] Specifically, the rear end cap is provided with a pressure testing interface and an ignition interface.

[0015] Specifically, the rear end face of the propellant grain can be adhesively bonded to the ignition charge, and the ignition wire of the ignition charge is led out through the ignition interface.

[0016] Specifically, a pressure sensor is provided at the pressure measurement interface.

[0017] The working method of the high combustion efficiency propellant-type water spur test engine is as follows: when the engine is working, the propellant propellant gradually burns and moves backward, and the front end of the piston begins to fill with gas to increase the pressure. The piston movement is controlled by the gas pressure. When the gas pressure is greater than the combustion chamber pressure, it can push the piston to keep the burning surface of the propellant propellant propellant at the optimal constant distance from the water jet nozzle, ensuring that the combustion efficiency is maintained at the highest level.

[0018] Compared with the prior art, the present invention has the following technical effects:

[0019] The high-efficiency propellant-grain water ramjet test engine provided by this invention, after the engine enters the working state, uses gas pressure to control the piston movement. When the gas pressure is greater than the combustion chamber pressure, the propellant grain moves backward, generating a corresponding displacement. By controlling the pressure, the propellant grain's backward combustion surface and the water nozzle are always kept at the optimal distance, ensuring that the metallic fuel reacts fully with water to maintain high combustion efficiency, generate more energy, and ensure the engine's specific impulse performance. This high-efficiency propellant-grain water ramjet test engine lays the foundation for the development and testing of water ramjet engine prototypes and provides a theoretical and technical basis for the application of ultra-high-speed underwater propulsion systems. Attached Figure Description

[0020] Figure 1 This is a cross-sectional view of the overall structure of the engine according to an embodiment of the present invention.

[0021] Figure 2 This is a three-dimensional isometric view of the engine outer cylinder in an embodiment of the present invention.

[0022] Figure 3 This is a three-dimensional isometric view of the engine inner cylinder in an embodiment of the present invention.

[0023] Figure 4 This is a three-dimensional isometric view of the engine injection component in an embodiment of the present invention.

[0024] Figure 5 This is a three-dimensional isometric view of the engine rear end cap in an embodiment of the present invention.

[0025] The meanings of the labels in the diagram are as follows:

[0026] 1. Front end cap; 2. Outer cylinder; 3. Inner cylinder; 4. EPDM piston; 5. High-temperature resistant ceramic composite (W / UHTCs) piston; 6. Coating layer; 7. Propellant grain; 8. Injection part; 9. Rear end cap; 10. Afterburner chamber; 11. Nozzle; 12. Ignition charge. Detailed Implementation

[0027] The following are specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments. All equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0028] Example 1:

[0029] like Figures 1 to 5As shown, this embodiment provides a high-combustion-efficiency propellant-type water ramming test engine, including a front end cap 1, an outer cylinder 2, an inner cylinder 3, a piston, a propellant grain 7, an injection nozzle 8, a rear end cap 9, a combustion chamber 10, and a nozzle 11; the front end cap 1, the outer cylinder 2, the rear end cap 9, the combustion chamber 10, and the nozzle 11 are connected in sequence; the inner cylinder 3 is located inside the outer cylinder 2, the piston and the propellant grain 7 are located inside the inner cylinder 3 and are in close contact with the inner wall of the inner cylinder 3, and the annular injection nozzle 8 is located at the rear end of the inner cylinder 3.

[0030] The front end of the front end cap 1 can be connected to an external air supply system, and the rear end face of the front end cap 1 is in contact with the front end face of the inner cylinder 3. The front and rear ends of the inner cylinder 3 are sealed by sealing rings, forming a water flow interlayer between it and the outer cylinder 2. The outer cylinder 2 is provided with multiple water inlets, and external water can enter the water flow interlayer through the water inlets. The water flow in the water flow interlayer provides water flow to the engine combustion chamber and cools the engine cylinder, thereby reducing the design process of the insulation layer. The water inlets are welded to the outer cylinder 2 and connected to the external water inlet device to provide the engine with a certain pressure of water flow. The water flow can be controlled by controlling the external pressure. The rear of the inner cylinder 3 is circumferentially provided with multiple round holes that correspond to the injection part 8 to form a water flow channel. Specifically, the rear end of the inner cylinder 3 is designed with 24 holes. The injection part 8 has 8 small round holes. The front and rear ends of the injection part 8 are sealed with sealing rings, and its side walls are circumferentially provided with multiple small round holes. Specifically, the injection part 8 has 8 small round holes. The water entering the water flow interlayer through the small round orifice is injected into the combustion chamber inside the inner cylinder 3 via the round orifice, water flow channel, and small round orifice. The water flow is injected into the combustion chamber through the small round orifice, and by adjusting the external water inlet pressure, the water outlet is in a spray state. The atomized water reacts with the metallic fuel in the combustion chamber, releasing energy, which does work and generates thrust. The piston front end can contact the gas filled at the front end cap 1 interface, and the rear end is tightly bonded to the propellant grain 7 coating layer 6, ensuring precise and controllable displacement. The piston front end contacts the filling gas, and the piston movement is controlled by the gas pressure. When the gas pressure is greater than the combustion chamber pressure, the propellant grain 7 moves to the rear end, generating a corresponding displacement.

[0031] The piston consists of two parts: the front part is made of heat-insulating material, specifically EPDM piston 4, and the rear part is made of high-temperature resistant ceramic composite material, specifically W / UHTCs piston 5. The two parts are tightly bonded together with an adhesive to form a whole.

[0032] The propellant grain 7 is a water-rich reactive metal fuel propellant, including a composite solid propellant rich in metal powders such as Al, Mg, and Li. In this embodiment, it is specifically a composite solid propellant rich in Al metal powder (80% wt).

[0033] The propellant grain 7 has a coating layer 6 on its front end face and side wall, so that the combustion surface of the propellant grain 7 is only on the rear end face.

[0034] The front end cap 1 is threaded to the front end of the outer cylinder 2; the rear end cap 9 is threaded to the rear end of the outer cylinder 2, and its front end face is in contact with the end face of the injection component 8; the afterburning chamber 10 is threaded to the rear end cap 9; and the nozzle 11 is threaded to the afterburning chamber 10.

[0035] The nozzle 11 consists of a converging section, a throat, and a diverging section from front to back. The converging section is connected to the afterburner chamber 10 by a thread, and the diverging section is open to the outside. The nozzle 11 is lined with an erosion-resistant material to prevent metal particles from eroding the throat, causing it to enlarge, changing the divergence ratio, and affecting the specific impulse performance.

[0036] The rear end cap 9 is equipped with a pressure testing interface and an ignition interface.

[0037] The rear end face of the propellant grain 7 can be glued to the ignition charge 12, and the ignition wire of the ignition charge 12 is led out through the ignition interface.

[0038] A pressure sensor is installed at the pressure measurement interface.

[0039] The assembly sequence of the high combustion efficiency propellant-type water-jet test engine of this invention is as follows:

[0040] First, a sealing ring is fitted into the sealing groove at the rear end of the front end cap and connected to the outer cylinder via threads. Sealing rings are then fitted into the sealing grooves at both ends of the inner cylinder and inserted into the inner cavity of the outer cylinder. Next, a strong adhesive is used to bond the EPDM piston and the high-temperature resistant ceramic composite piston (W / UHTCs) to form a single unit. This integrated piston is then inserted into the inner cylinder until it reaches the predetermined positioning groove. A strong adhesive is applied to the bottom of the propellant grain outer casing, which is then inserted into the inner cylinder, with the bottom end connected to the ceramic composite piston. Plug in contact; fit sealing rings into the sealing grooves at both ends of the injection component, insert the lower end into the inner cylinder cavity, and press the higher end against the end face of the inner cylinder; use resin adhesive to bond the propellant grain end face of the pre-loaded ignition charge, lead out the ignition wire through the ignition interface on the rear end cap, and then connect the rear end cap to the outer cylinder 2 via threads, with the leftmost end face of the rear end cap pressed against the rear end face of the injection component; fit a sealing ring onto the rear port of the rear end cap, and then connect it to the afterburner chamber via threads; connect the nozzle to the afterburner chamber via threads.

[0041] Specifically, the inner and outer cylinders together form a water flow jacket; the water inlet is welded to the outer cylinder and serves as a channel for external water medium to enter the jacket chamber. At the same time, this channel forms a regenerative cooling system. The external water medium is heated in the jacket chamber to increase the engine's thermal efficiency. The high-speed flow of the water medium carries away a large amount of heat from the engine casing, causing the engine casing temperature to drop, which can effectively reduce the thermal protection pressure of the combustion chamber.

[0042] Engine ignition is achieved by igniting the propellant charge with an ignition charge, which is mainly composed of large black particles, small black particles, magnesium powder, and polytetrafluoroethylene. The electric ignition head is encased in the ignition charge.

[0043] The pressure sensor is connected to the sensor interface on the rear end cap to measure pressure changes during engine operation.

[0044] The assembled engine is then connected to the external air and water supply systems. The front end cap connects to the external air intake pipe, while the four water inlets on the outer cylinder connect to the external water supply pipe.

[0045] Example 2:

[0046] This embodiment provides a working method for a high-combustion-efficiency propellant-type water spur test engine. When the engine is working, the propellant grain gradually burns and moves backward, and the piston front end begins to be filled with gas to increase the pressure. The piston movement is controlled by the gas pressure. When the gas pressure is greater than the combustion chamber pressure, it can push the piston to keep the propellant grain burning surface at the optimal constant distance from the water jet nozzle, ensuring that the combustion efficiency is maintained at the highest level.

[0047] Specifically, the timing sequence of ignition, air intake, and water intake is controlled by an external measurement and control system. After the engine receives the ignition command, the ignition charge ignites and ignites the propellant grain. The external air intake and water intake system triggers the timing sequence to start working until the propellant grain is completely burned.

[0048] More specifically, the air intake sequence triggers the solenoid valve within 10ms after ignition, and the gas pushes the piston so that the displacement of the propellant grain is proportional to the propellant burning rate; the water intake sequence triggers the solenoid valve to open the water intake device 200ms after the propellant grain begins to burn, allowing external water medium to enter the water flow jacket through the water inlet, and then enter the combustion chamber to participate in the reaction through the water flow nozzle of the injection component. After the initial reaction, the gas-solid two-phase flow enters the afterburner to continue the reaction, and finally the working fluid formed in the afterburner is sprayed out at high speed through the nozzle to do work, thereby generating thrust.

[0049] This invention calibrates the water flow rate of the entire system before conducting ignition tests, that is, explores the relationship between water pressure (MPa) and water flow rate (Kg / s) so that the water pressure can be controlled to regulate the water flow rate entering the combustion chamber when the engine is working; the flow rate calibration process is carried out before the loading of propellant grains in the assembly sequence.

[0050] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0051] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0052] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A high-efficiency propellant-filled water-jet test engine, characterized in that, It includes a front end cap (1), an outer cylinder (2), an inner cylinder (3), a piston, a propellant grain (7), an injection nozzle (8), a rear end cap (9), a combustion chamber (10), and a nozzle (11); the front end cap (1), the outer cylinder (2), the rear end cap (9), the combustion chamber (10), and the nozzle (11) are connected in sequence; the inner cylinder (3) is located inside the outer cylinder (2), the piston and the propellant grain (7) are located inside the inner cylinder (3) and are close to the inner wall of the inner cylinder (3), and the annular injection nozzle (8) is located at the rear end of the inner cylinder (3); The front end of the front end cap (1) can be connected to an external gas source, and the rear end face of the front end cap (1) is in contact with the front end face of the inner cylinder (3). The front and rear ends of the inner cylinder (3) are sealed by a sealing ring and form a water flow interlayer between it and the outer cylinder (2). The outer cylinder (2) is provided with multiple water inlets and external water flow can enter the water flow interlayer through the water inlets. The rear part of the inner cylinder (3) is provided with multiple round holes in the circumferential direction and corresponds to the injection component (8) to form a water flow channel. The front and rear ends of the injection component (8) are sealed by a sealing ring and its side wall is provided with multiple small round holes in the circumferential direction. The water flow entering the water flow interlayer can be injected into the combustion chamber inside the inner cylinder (3) in sequence through the round holes, water flow channel and small round holes. The front end of the piston can contact the gas filled by the front end cap (1) interface and the rear end is tightly bonded to the coating layer (6) of the propellant grain (7).

2. The high combustion efficiency propellant-type water ramming test engine as described in claim 1, characterized in that, The piston consists of two parts: the front part is made of heat-insulating material and the rear part is made of high-temperature resistant ceramic composite material. The two parts are tightly bonded together with an adhesive to form a whole.

3. The high combustion efficiency propellant-type water ramming test engine as described in claim 1, characterized in that, The propellant grain (7) is a water-rich reactive metal fuel propellant, including a composite solid propellant rich in Al, Mg and Li metal powders.

4. The high combustion efficiency propellant-type water ramming test engine as described in claim 1, characterized in that, The propellant grain (7) has a coating layer (6) on its front end face and side wall, so that the combustion surface of the propellant grain (7) is only on the rear end face.

5. The high combustion efficiency propellant-filled water-jet test engine as described in claim 1, characterized in that, The front end cap (1) is threaded to the front end of the outer cylinder (2); the rear end cap (9) is threaded to the rear end of the outer cylinder (2), and the front end face is in contact with the end face of the injection component (8); the combustion chamber (10) is threaded to the rear end cap (9); the nozzle (11) is threaded to the combustion chamber (10).

6. The high combustion efficiency propellant-filled water-jet test engine as described in claim 1, characterized in that, The nozzle (11) consists of a converging section, a throat, and an expanding section from front to back. The converging section is connected to the combustion chamber (10) by a thread, and the expanding section is connected to the outside.

7. The high combustion efficiency propellant-filled water-jet test engine as described in claim 1, characterized in that, The rear end cap (9) is provided with a pressure testing interface and an ignition interface.

8. The high combustion efficiency propellant-filled water spur test engine as described in claim 7, characterized in that, The rear end face of the propellant grain (7) can be glued to the ignition charge (12), and the ignition wire of the ignition charge (12) is led out through the ignition interface.

9. The high combustion efficiency propellant-filled water spur test engine as described in claim 7, characterized in that, A pressure sensor is installed at the pressure measurement interface.

10. The operating method of the high combustion efficiency propellant-filled water-jet test engine according to any one of claims 1 to 9, characterized in that, When the engine is running, the propellant grain gradually burns and moves backward. The piston front begins to fill with gas to increase the pressure. The piston movement is controlled by the gas pressure. When the gas pressure is greater than the combustion chamber pressure, it can push the piston to keep the propellant grain burning surface at the optimal constant distance from the water injection nozzle, ensuring that the combustion efficiency is maintained at its highest level.

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