A closed combustion chamber suitable for use in an unmanned underwater vehicle and methods of use thereof

Abstract

The application relates to a sealed combustion chamber suitable for an unmanned underwater vehicle and a use method thereof, and relates to the technical field of underwater vehicle thermal power. In the application, an upper end cover, a lower end cover and an outer shell constitute a combustion chamber outer shell, and the three parts are detachably connected, and the outer shell is provided with a cooling water channel. The outer shell, a metal bushing and an inner shell form a three-layer sleeve structure, a resistance wire is arranged on the inner side wall of the inner shell, and a liquid absorbing core is arranged in the inner cavity of the inner shell; a spark plug, an electrode and an oxidizing gas nozzle are extended from the upper end cover to the inside of the inner shell. The method is as follows: solid-state metal fuel is arranged at the bottom of the inner cavity of the combustion chamber, the metal fuel is heated through the resistance wire, and the combustion chamber power is controlled by adjusting the oxidizing gas input amount. The application has the advantages of quick starting, quick replacement of the liquid absorbing core, non-clogging of the nozzle, low-power operation and the like, and can meet the demand of UUV low-speed cruising.

Description

Technical Field

[0001] This invention relates to the field of underwater vehicle thermal power technology, specifically to a sealed combustion chamber suitable for unmanned underwater vehicles and its usage method. Background Technology

[0002] Unmanned underwater vehicles (UUVs) have broad application prospects in both military and civilian fields, and the research level of power and propulsion technologies largely determines the speed and quality of UUV development. To meet the current rapid development of UUVs, research into novel propulsion systems characterized by small size, light weight, high energy density, and no wake is urgently needed. Summary of the Invention

[0003] To meet the current development needs of UUVs, this invention provides a sealed combustion chamber suitable for unmanned underwater vehicles and its usage method.

[0004] A sealed combustion chamber for an unmanned underwater vehicle according to the present invention includes an upper end cover 2, a lower end cover 3, an outer shell 7, a metal bushing 6, an inner shell 5, a liquid-absorbing core 4, a resistance wire 17, a spark plug, electrodes, and an oxidizing gas nozzle. Cooling water channels are provided inside the upper end cover 2, the lower end cover 3, and the side wall of the outer shell 7. The upper end of the outer shell 7 is detachably connected to the upper end cover 2, and the lower end of the outer shell 7 is detachably connected to the lower end cover 3. The cooling water channels of the upper end cover 2, the lower end cover 3, and the side wall of the outer shell 7 are all provided. The cooling water channels of the end cap 2 are connected in sequence; the lower end cap 3 is provided with a combustion product outlet; the outer shell 7, the metal bushing 6, and the inner shell 5 form a three-layer sleeve structure, which is located in the cavity surrounded by the upper end cap 2, the lower end cap 3, and the outer shell 7; the cavity inside the inner shell 5 serves as the combustion chamber, the resistance wire 17 is arranged on the side wall of the combustion chamber, and the liquid suction core 4 is arranged in the combustion chamber; the spark plug, electrode, and oxidizing gas nozzle extend from the upper end cap 2 into the interior of the inner shell 5.

[0005] Optionally, the top of the liquid-absorbing core 4 is fixed to the top of the internal cavity of the inner housing 5.

[0006] Optionally, the liquid-absorbing core 4 is cylindrical.

[0007] Optionally, the top of the liquid-absorbing core 4 is fixed to the top of the internal cavity of the inner housing 5 by a circular fixing mechanism.

[0008] Optionally, the absorbent core 4 is made of stainless steel.

[0009] The above-mentioned method for using the sealed combustion chamber of an unmanned underwater vehicle includes: Step 1, placing solid metal fuel at the bottom of the combustion chamber and purging the combustion chamber with inert gas; Step 2, turning on the power supply of the resistance wire 17, and turning off the power supply of the resistance wire 17 after the solid metal fuel melts and reaches a preset temperature; Step 3, supplying oxidizing gas into the combustion chamber through the oxidizing gas nozzle, and igniting the spark plug when the oxidizing gas in the combustion chamber reaches a preset concentration, and supplying cooling water to the cooling water channel; Step 4, after the combustion reaction between the oxidizing gas and the metal fuel reaches a stable state, turning off the spark plug ignition, and controlling the power of the combustion chamber by adjusting the input of the oxidizing gas; Step 5, if the unmanned underwater vehicle needs to stop operating, stopping the input of the oxidizing gas.

[0010] Optionally, the method further includes: step six, if the unmanned underwater vehicle needs to be restarted repeatedly and the temperature of the metal fuel is higher than the preset temperature, then steps three to five are repeated; if the unmanned underwater vehicle needs to be restarted repeatedly and the temperature of the metal fuel has not reached the preset temperature, then steps two to five are repeated.

[0011] Optionally, the method further includes: step seven, if the metal fuel is exhausted, then the combustion products are discharged from the fuel product outlet.

[0012] This invention relates to a sealed combustion chamber suitable for unmanned underwater vehicles (UUVs). A liquid-absorbing core stably delivers metallic fuel upwards. Heating the metallic fuel with a resistance wire, combined with various insulation structures, rapidly melts the fuel, enabling quick start-up. Repeated starting of the combustion chamber is achieved through the use of spark plugs and oxidizing gas nozzles. The liquid-absorbing core is a consumable component and can be quickly replaced by removing only the lower end cap. The nozzle is separated from both the fuel and the byproducts, reducing the risk of nozzle clogging during repeated start-ups. It can maintain low-power operation, meeting the requirements of low-speed cruising for UUVs. Attached Figure Description

[0013] Figure 1 An exploded view of a sealed combustion chamber suitable for an unmanned underwater vehicle according to an embodiment of the present invention is shown;

[0014] Figure 2 An axial sectional view of a sealed combustion chamber suitable for an unmanned underwater vehicle according to an embodiment of the present invention is shown;

[0015] Figure 3 A schematic diagram of the structure of the upper end cover according to an embodiment of the present invention is shown;

[0016] Figure 4A schematic diagram of the fixing mechanism of the liquid suction core according to an embodiment of the present invention is shown.

[0017] In the above figures, 1. Sealing end cap, 2. Upper end cap, 3. Lower end cap; 4. Liquid suction core, 5. Inner shell, 6. Metal bushing, 7. Outer shell, 8. Cooling water outlet connector, 9. Cooling water inlet connector, 10. Sealing gasket, 11. Upper end cap sealing gasket, 12. Lower end cap sealing gasket, 13. Spark plug, 14. Oxidizing gas nozzle, 15. Electrode ceramic protective sleeve, 16. Nozzle ceramic protective sleeve, 17. Resistance wire, 18. Combustion product outlet. Detailed Implementation

[0018] To make the technical solutions and advantages of the embodiments of this application clearer, the exemplary embodiments of this application will be described in further detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not an exhaustive list of all embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0019] Figure 1 and Figure 2 Exploded view and axial sectional view of a sealed combustion chamber suitable for an unmanned underwater vehicle according to an embodiment of the present invention are shown respectively.

[0020] like Figure 1 and Figure 2 As shown, the sealed combustion chamber of the present invention, applicable to unmanned underwater vehicles, mainly includes an upper end cover 2, a lower end cover 3, an outer shell 7, a metal bushing 6, an inner shell 5, a liquid suction core 4, a resistance wire 17, a spark plug, an electrode, and an oxidizing gas nozzle.

[0021] The upper end cover 2, lower end cover 3, and outer shell 7 constitute the outer shell of the combustion chamber. Cooling water channels are provided inside the upper end cover 2, the lower end cover 3, and the side wall of the outer shell 7, and these three cooling water channels are interconnected to ensure the normal flow of cooling water within the sealed combustion chamber suitable for unmanned underwater vehicles. The inlet of the cooling water channel is located in the lower end cover 3, and a threaded hole is provided on the side of the lower end cover 3. This threaded hole is threadedly connected to the cooling water inlet connector 9 and communicates with the cooling water channel. The outlet of the cooling water channel is located in the upper end cover 2, and a threaded hole is provided on the side of the upper end cover 2. This threaded hole is threadedly connected to the cooling water outlet connector 8 and communicates with the cooling water channel. Cooling water enters from the cooling water channel inlet of the lower end cover 3, passes through the cooling water channel of the outer shell 7, and flows out from the cooling water channel outlet of the upper end cover 2.

[0022] The top of the outer casing 7 is connected to the upper end cover 2 by a pin, and a sealing gasket 10 is provided at the connection. The bottom of the outer casing 7 is connected to the lower end cover 3 by a pin, and a sealing gasket 10 is also provided at the connection. The sealing gasket 10 ensures the airtightness of the cooling water passage at the connection between the upper end cover 2 and the outer casing 7, as well as the airtightness of the connection between the lower end cover 3 and the outer casing 7, preventing cooling water from flowing into the combustion chamber cavity and affecting the operation of the combustion chamber. A sealing end cover 1 is also provided at the top of the upper end cover 2. The upper end of the upper end cover 2 is connected to the sealing end cover 1 by a pin, and the lower end is connected to the outer casing 7 by a pin. A combustion product outlet 18 is provided at the center of the lower end cover 3.

[0023] The outer shell 7, the metal bushing 6, and the inner shell 5 form a three-layer sleeve structure. The outer shell 7 is located outside the metal bushing 6, and there is a cavity between the outer shell 7 and the metal bushing 6. The inner shell 5 is located inside the metal bushing 6. The upper end cover 2, the lower end cover 3, and the outer shell 7 form a cavity, and the three-layer sleeve structure is located within this cavity. An upper end cover sealing gasket 11 is provided at the mating point between the upper end cover 2 and the inner shell 5, and a lower end cover sealing gasket 12 is provided at the mating point between the lower end cover 3 and the inner shell 5.

[0024] The cavity inside the inner shell 5 serves as the combustion chamber, providing a storage area for fuel, a storage area for combustion products, and a combustion reaction zone. Its service life directly affects the lifespan of the combustion chamber, which acts as a sealed heat source. The inner shell 5 is made of high-temperature resistant ceramic, which better adapts to the high-temperature environment inside the combustion chamber, extending its service life.

[0025] A resistance wire 17 is arranged on the side wall of the combustion chamber cavity. A groove can be formed in the side wall, and the resistance wire 17 is arranged in the groove. The resistance wire 17 is used to heat the solid fuel to melt. When the resistance wire 17 heats, the cavity structure between the outer shell 7 and the metal bushing 6 increases the thermal resistance for heat transfer to the outside, thereby causing the temperature of the solid fuel to rise rapidly and accelerating the start-up speed of the combustion chamber. This cavity structure increases the thermal resistance for heat transfer to the outside when the resistance wire 17 heats the solid lithium. A liquid absorber 4 is arranged in the combustion chamber cavity. The preferred structure of the liquid absorber 4 is a cylindrical structure surrounded by a metal mesh, with its central axis parallel to the central axis of the three-layer sleeve structure. The top of the liquid absorber 4 can be fixed to the top of the internal cavity of the inner shell 5 by a disc-shaped fixing mechanism. The structure of the fixing mechanism is as follows... Figure 4 As shown, the fixing mechanism has several holes and is fixed to the inner housing 5 with screws. The suction core 4 is a consumable part and needs to be replaced regularly. To replace the suction core 4, simply open the lower end cover 3 and remove the screws, which allows for quick replacement of the suction core 4.

[0026] The aforementioned sealed combustion chamber uses a spark plug 13 as the ignition device. Holes are made in the fixing mechanism of the upper end cap 2 and the liquid-absorbing core 4, through which the spark plug 13, the electrode ceramic protective sleeve 15, and the nozzle ceramic protective sleeve 16 extend into the inner cavity of the combustion chamber. Correspondingly, the sealing end cap 1 also has a hole for introducing oxidizing gas into the oxidizing gas nozzle 14. The electrode ceramic protective sleeve 15 houses the electrode, and the nozzle ceramic protective sleeve 16 houses the oxidizing gas nozzle 14. A cavity structure is provided at the mating point between the electrode ceramic protective sleeve 15 and the upper end cap 2 and inner shell 5 to increase the thermal resistance between the upper end cap 2, inner shell 5, and the oxidizing gas nozzle 14 and electrode, preventing abnormal operation of the oxidizing gas nozzle and electrode due to excessive temperature.

[0027] The aforementioned sealed combustion chamber uses metallic lithium as fuel and sulfur hexafluoride gas as the oxidizing gas. The reaction between lithium and sulfur hexafluoride releases a high amount of heat; 1 kg of lithium can release 46,800 kJ of heat. Furthermore, the products of the reaction are all liquid, and their volume is smaller than the volume of the consumed lithium liquid. Therefore, even without adding new storage devices, there is no need to discharge the products to the outside during device operation. These characteristics perfectly meet the requirements of a UUV. Solid lithium is placed inside the combustion chamber, with its height greater than three-fifths and less than two-thirds of the chamber's height. This ensures that the melted solid lithium can submerge the lower end of the wick 4, provides sufficient space for the combustion reaction, and prevents the resistance wire 17 from burning out due to no-load operation.

[0028] Resistance wire 17 heats solid lithium metal, melting it into a liquid state. The distance between the bottom of the wick 4 and the top of the inner shell 5 is approximately three-fifths of the combustion chamber cavity. The function of the wick 4 is to continuously transport fuel from its lower part to its upper part via capillary action, allowing it to evaporate and sustain combustion. The density of the combustion products is slightly greater than that of liquid lithium. These products flow back along the wick 4 and the inner wall of the inner shell 5 to the bottom of the inner shell 5, ensuring that the bottom of the wick 4 is fully immersed in the liquid lithium. This ensures that sufficient liquid lithium is transported to the upper part of the wick 4, preventing it from burning out and preventing the combustion products from being re-transported to the upper part, thus stopping the combustion reaction. Since the wick 4 is in direct contact with the liquid lithium and oxidant and operates in a high-temperature environment, it is highly susceptible to corrosion. Therefore, stainless steel is the preferred material for the wick 4 to prevent corrosion and ensure the combustion chamber's performance. The resistance wire 17 is placed at the bottom of the inner shell 5. The height of the resistance wire 17 is about three-fifths of the height of the combustion chamber. This position can increase the contact area between the lithium metal and the resistance wire 17, so that the temperature of the lithium metal can rise rapidly during heating to achieve the purpose of rapid start-up, and the resistance wire 17 will not be run unloaded, thus causing the resistance wire 17 to burn out.

[0029] During combustion chamber operation, combustion products are gradually generated. Since the volume of these products is smaller than the volume of consumed lithium liquid, the lithium liquid level gradually decreases. To improve the stability of the combustion chamber's power output, a denser liquid can be slowly introduced into the combustion chamber from the bottom to raise the lithium liquid level. Specifically, the power output of the combustion chamber is monitored, and the rate of liquid input is controlled based on the relationship between the power output and the lithium liquid level, enabling the combustion chamber to operate more stably.

[0030] The above-mentioned method for using the sealed combustion chamber of an unmanned underwater vehicle is as follows:

[0031] Step 1: Place solid lithium at the bottom of the combustion chamber and purge the combustion chamber with an inert gas (such as argon) to prevent the metal fuel placed in the combustion chamber from being oxidized by the air.

[0032] Step 2: Turn on the power supply of resistance wire 17 to heat the solid lithium. When the solid lithium melts and reaches the preset temperature, turn off the power supply of resistance wire 17 to stop heating.

[0033] Step 3: Sulfur hexafluoride oxidizing gas is delivered into the combustion chamber through the oxidizing gas nozzle. When the oxidizing gas in the combustion chamber reaches the preset concentration, the spark plug is started for ignition, and the inlet and outlet connectors of the cooling water are opened to allow the cooling water to flow along the cooling water channel.

[0034] Step 4: Once the combustion reaction between sulfur hexafluoride gas and lithium has reached a stable state, turn off the ignition device and control the power of the combustion chamber by adjusting the input of sulfur hexafluoride gas.

[0035] Step 5: If the unmanned underwater vehicle needs to be shut down, stop the input of oxidizing gas;

[0036] Step 6: If the unmanned underwater vehicle needs to be restarted repeatedly and the restart interval is short, that is, the lithium temperature is higher than the preset temperature when restarting, then repeat steps 3 to 5; if the unmanned underwater vehicle needs to be restarted repeatedly and the restart interval is long, that is, the lithium temperature does not reach the preset temperature when restarting, then repeat steps 2 to 5.

[0037] Step 7: If lithium is depleted, discharge the combustion products from the fuel product outlet and replace the wick 4 after the combustion chamber has cooled down.

[0038] Using the sealed combustion chamber described above, suitable for unmanned underwater vehicles, allows for rapid start-up and quick replacement of the liquid suction core 4. The combustion chamber can maintain stable operation at a relatively low power, making it very suitable for low-speed cruising UUVs.

[0039] Although the invention has been described with reference to a limited number of embodiments, those skilled in the art will understand from the foregoing description that other embodiments are conceivable within the scope of the invention described herein. Furthermore, it should be noted that the language used in this specification has been chosen primarily for readability and instructional purposes, and not for the purpose of explaining or limiting the subject matter of the invention.

Claims

1. A method of using a sealed combustion chamber suitable for an unmanned underwater vehicle, the sealed combustion chamber comprising an upper end cover (2), a lower end cover (3), an outer shell (7), a metal bushing (6), an inner shell (5), a liquid suction core (4), a resistance wire (17), a spark plug, an electrode, and an oxidizing gas nozzle; Cooling water channels are provided inside the upper end cover (2), the lower end cover (3), and the side wall of the outer shell (7). The upper end of the outer shell (7) is detachably connected to the upper end cover (2), and the lower end of the outer shell (7) is detachably connected to the lower end cover (3). The cooling water channels of the upper end cover (2), the outer shell (7), and the upper end cover (2) are connected in sequence. The lower end cap (3) is provided with a combustion product outlet; The outer shell (7), the metal bushing (6), and the inner shell (5) form a three-layer sleeve structure, which is located in the cavity surrounded by the upper end cover (2), the lower end cover (3), and the outer shell (7); The cavity inside the inner shell (5) serves as the combustion chamber cavity, the resistance wire (17) is arranged on the side wall of the combustion chamber cavity, and the liquid suction core (4) is arranged in the combustion chamber cavity. The spark plug, electrode and oxidizing gas nozzle extend from the upper end cap (2) into the interior of the inner housing (5); Its features are, The method of use includes: Step 1: Place solid metal fuel at the bottom of the combustion chamber and purge the combustion chamber with inert gas; Step 2: Turn on the power supply of the resistance wire (17), wait for the solid metal fuel to melt and reach the preset temperature, then turn off the power supply of the resistance wire (17). Step 3: Oxidizing gas is supplied to the combustion chamber through the oxidizing gas nozzle. Once the oxidizing gas concentration in the combustion chamber reaches the preset level, the spark plug is activated for ignition, and cooling water is supplied to the cooling water passage. Step 4: Once the combustion reaction between the oxidizing gas and the metal fuel has reached a stable state, turn off the spark plug ignition and control the power of the combustion chamber by adjusting the input amount of the oxidizing gas. Slowly input a liquid with a density greater than that of the lithium liquid into the combustion chamber from the bottom of the combustion chamber, detect the output power of the combustion chamber, and control the input speed of the liquid according to the change law of the output power of the combustion chamber with the height of the lithium liquid level. Step 5: If the unmanned underwater vehicle needs to be shut down, then stop the input of the oxidizing gas.

2. The method as described in claim 1, characterized in that, The top of the liquid-absorbing core (4) is fixed to the top of the cavity inside the inner shell (5).

3. The method as described in claim 1, characterized in that, The liquid-absorbing core (4) is cylindrical.

4. The method as described in claim 3, characterized in that, The top of the liquid-absorbing core (4) is fixed to the top of the cavity inside the inner shell (5) by a circular fixing mechanism.

5. The method as described in claim 1, characterized in that, The absorbent core (4) is made of stainless steel.

6. The method as described in claim 1, characterized in that, Also includes: Step 6: If the unmanned underwater vehicle needs to be restarted repeatedly and the temperature of the metallic fuel is higher than the preset temperature, then repeat steps 3 to 5; if the unmanned underwater vehicle needs to be restarted repeatedly and the temperature of the metallic fuel has not reached the preset temperature, then repeat steps 2 to 5.

7. The method as described in claim 1 or 6, characterized in that, Also includes: Step 7: If the metallic fuel is exhausted, the combustion products are discharged from the fuel product outlet.

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