A drag reduction device for amphibious vehicles using supercavitation

Abstract

The present disclosure provides a drag reduction device for an amphibious vehicle body using supercavitation for navigation on water. The device includes an exhaust gas collection device, a compressed gas storage device, an expansion unit, a thermostat, a gas delivery assembly, and a supercavitation launch device. The exhaust gas collection device collects and filters the exhaust gas generated by the amphibious vehicle engine, and compresses and stores it in the compressed gas storage device. During use, the gas is pressure- and temperature-regulated by the expansion unit and the thermostat, and then delivered to the supercavitation launch device provided at the bow of the amphibious vehicle body via the delivery assembly. The gas with the required pressure and stable temperature is emitted outward through the holes on the supercavitation launch device, forming supercavitation around the holes for drag reduction. The use of the present invention can reduce the resistance encountered by an amphibious vehicle during navigation on water.

Description

Technical Field

[0001] The present invention relates to the technical field of underwater drag reduction of amphibious vehicles, and in particular to a water navigation drag reduction device for an amphibious vehicle body utilizing supercavitation. Background Art

[0002] Currently, amphibious vehicles are often subject to significant water resistance when navigating on water, resulting in increased energy consumption and limited speed. Water resistance is particularly important when navigating water, and this factor significantly impacts efficiency. Therefore, effectively reducing resistance during navigating water has been a research hotspot in amphibious vehicle technology.

[0003] In many industrial applications, cavitation is generally considered a detrimental phenomenon, as it can lead to performance degradation and structural damage in hydraulic machinery. However, when navigating underwater, when a cavity surrounds a vehicle body, the surface of the vehicle contacts a gaseous fluid—for example, water vapor, air, exhaust gas—rather than liquid water. This significantly reduces the drag experienced by the vehicle while traveling through water. Cavitation can be categorized into two types: natural cavitation and ventilated cavitation, depending on the mechanism of cavitation formation.

[0004] Natural cavitation is primarily formed by pressure changes in fluid dynamics, while ventilated cavitation is a form of artificial cavitation created by injecting non-condensable gases, such as air or exhaust gas, into a liquid flow field. Both types of cavitation have broad application prospects in reducing drag on underwater vehicles and increasing speed and range.

[0005] Supercavitation occurs when a large, continuous gas cavity forms around the surface of an underwater vehicle, reducing the drag of the water flow on the object. Supercavitation can reduce the drag of a moving vehicle, enabling it to move at high speeds and stably underwater. When the flow around an object's surface is replaced by a layer of gas, both friction and pressure resistance are significantly reduced. This gas layer significantly reduces near-wall density and changes fluid viscosity, similar to the supercavitating flow around an underwater vehicle.

[0006] The use of supercavitation effect to reduce underwater resistance has not yet been applied to the drag reduction of amphibious vehicles on water. Summary of the Invention

[0007] In view of this, the present invention provides an amphibious vehicle water navigation drag reduction device using supercavitation, which can reduce the resistance encountered by the amphibious vehicle during water navigation.

[0008] In order to solve the above technical problems, the present invention is implemented as follows.

[0009] A supercavitation-based amphibious vehicle drag reduction device comprises an exhaust gas collection device, a compressed gas storage device, an expansion unit, a constant temperature device, a gas delivery assembly, and a supercavitation launch device.

[0010] The exhaust gas collection device is used to collect and filter the exhaust gas generated by the amphibious vehicle engine;

[0011] The compressed gas storage device is used to pressurize and store the filtered exhaust gas collected by the exhaust gas collection device through a compressor;

[0012] The expansion unit is used to expand the gas in the compressed gas storage device to reduce the gas pressure and temperature when sailing on water;

[0013] The constant temperature device is used to cool the depressurized gas and maintain the gas temperature within a certain range;

[0014] The gas, which has been regulated in pressure and temperature, is sent to the supercavitation launch device through the gas delivery assembly;

[0015] The supercavitation launcher is set at the bow of the amphibious vehicle and has a hole. It emits the gas with adjusted pressure and temperature to the outside, forming supercavitation around the hole for drag reduction.

[0016] Preferably, the tail gas collection device is provided with a filtering device to remove impurities and harmful gases contained in the tail gas.

[0017] Preferably, the compressed gas storage device compresses the gas using a compression unit and stores the compressed gas in a compressed gas tank.

[0018] Preferably, the outlet of the compressed gas tank is connected via a pneumatic valve.

[0019] Preferably, when the vessel is sailing on water, the expansion unit expands and exchanges heat on the gas in the compressed gas storage device through an expander, so that the pressure is reduced to a target pressure.

[0020] Preferably, the supercavitation launch device includes an upper bow skateboard and a lower bow skateboard, and the two parts are not connected; the upper bow skateboard and the lower bow skateboard are controlled by a hydraulic strut to control the folding state, and the folding state includes that there is an angle between the upper bow skateboard and the lower bow skateboard and covers the front surface of the amphibious vehicle body or is unfolded in the same plane and docked; the upper bow skateboard is a solid structure; the lower bow skateboard is divided into two layers, the inner layer is a solid structure, and the outer layer is a hollow structure, and a hole is opened on the outer surface of the lower part of the space.

[0021] Preferably, the hydraulic strut is connected to the upper bow slide via a fixed structure to fix and limit the unfolding angles of the upper bow slide and the lower bow slide.

[0022] Preferably, the hydraulic strut includes a left hydraulic strut and a right hydraulic strut.

[0023] Preferably, the gas delivery assembly is connected to the ventilation pipe of the constant temperature device and the supercavitation launch device. The ventilation pipe is a plurality of pipes evenly distributed at the bottom of the outer hollow structure of the lower bow slide, providing the hollow structure with gas with adjusted pressure and temperature.

[0024] Preferably, a pressure regulating valve and a temperature control valve are provided on the ventilation pipe to ensure that the gas introduced has the conditions to form supercavitation at the holes of the bow skateboard of the amphibious vehicle.

[0025] Beneficial effects:

[0026] (1) The present invention utilizes engine exhaust gas to generate supercavitation through treatment and pressure and temperature control, which can reduce the resistance encountered by amphibious vehicles during navigation on water.

[0027] (2) Compressed gas is expanded and reused. Compared with general supercavitation application scenarios, the flow rate required to form supercavitation on the lower side of the bow skateboard of an amphibious vehicle is larger, so an expansion unit is needed to increase the gas flow rate and control the exhaust gas pressure.

[0028] (3) The present invention uses a constant temperature device to help ensure the stability of gas flow and flow rate by maintaining the consistency of gas temperature, which helps to produce a more stable bubble layer and optimize the size and distribution of bubbles, thereby more effectively isolating water and the vehicle surface and reducing resistance.

[0029] (4) The supercavitation launch device is designed on the lower bow skateboard, which divides the lower bow skateboard into two layers, the outer layer is a cavity, and the lower part has a hole. The layered design can optimize the ratio of structural strength to weight, reduce the weight of the overall structure, and help improve the maneuverability and navigation performance of the amphibious vehicle.

[0030] (5) The compressed gas tank is output through the pneumatic valve control to control the flow of the discharged gas to ensure that the gas pressure and flow meet the requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic diagram of the principle of the amphibious vehicle water navigation drag reduction device using supercavitation in the present invention.

[0032] Figure 2 This is a schematic diagram of the bow ski of an amphibious vehicle;

[0033] Figure 3 Schematic diagram of the bow ski support rod.

[0034] Figure 4 Schematic diagram of the steps of the supercavitation drag reduction method of the present invention. DETAILED DESCRIPTION

[0035] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0036] The present invention provides an amphibious vehicle body water navigation drag reduction device using supercavitation. The device stores exhaust gas generated by the engine and processes the exhaust gas into gas with supercavitation forming conditions through pressure and temperature control during water navigation. The exhaust gas is then emitted outward through the holes of a supercavitation emission device, forming supercavitation around the holes, which is used for drag reduction during water navigation.

[0037] Figure 1 The schematic diagram of the present invention shows the principle of the amphibious vehicle water navigation drag reduction device using supercavitation. As shown in the figure, the device includes an exhaust gas collection device, a compressed gas storage device, an expansion unit, a constant temperature device, a gas transmission component, and a supercavitation launch device.

[0038] The exhaust gas collecting device is used to collect and filter the high-temperature exhaust gas generated by the amphibious vehicle engine. In a preferred embodiment, the exhaust gas collecting device is provided with a filtering device to remove impurities and harmful gases contained in the exhaust gas.

[0039] The compressed gas storage device is used to compress and store the filtered exhaust gas collected by the exhaust gas collection device through a compressor. In a preferred embodiment, the compressed gas storage device uses a compression unit to compress the gas and stores it in a compressed gas tank to ensure that the gas can be used for subsequent regulation.

[0040] The expansion unit is configured to expand the gas in the compressed gas storage device during navigation, thereby reducing the gas pressure and temperature. In a preferred embodiment, the expansion unit includes an expander. The gas stored in the compressed gas storage device enters the expander through a regulating valve for expansion and heat exchange, thereby increasing the gas flow rate and reducing the gas pressure to a target pressure. The unit also reduces the temperature of the high-pressure gas, thereby reducing the risk of supercavitation collapse.

[0041] The constant temperature device is used to cool the depressurized gas produced by the expansion unit to prevent uneven gas temperature and ensure that the gas temperature is stable within the range of 20 to 50°C.

[0042] The pressure- and temperature-regulated gas is delivered to the supercavitating launcher via a gas delivery assembly. In a preferred embodiment, the gas delivery assembly comprises multiple ventilation pipes, for example, three ventilation pipes, connecting the amphibious vehicle body and the supercavitating launcher. The gas, after being treated by the thermostat, enters the supercavitating launcher through the three ventilation pipes.

[0043] The supercavitation launcher is set at the bow of the amphibious vehicle and has a hole. It emits the gas with adjusted pressure and temperature to the outside, forming supercavitation around the hole for drag reduction.

[0044] Figure 2 and Figure 3 A schematic diagram of the supercavitation launcher of the present invention is shown. As shown, the supercavitation launcher comprises an upper bow slide 1 and a lower bow slide 2, which are not connected. Hydraulic struts control the folding state of the upper and lower bow slides 1 and 2. These folding states can be either angled and covering the front surface of the amphibious vehicle, or deployed in the same plane and docked. In this embodiment, two hydraulic struts are used: a left hydraulic strut 7 and a right hydraulic strut 8, which support the left and right sides of the upper and lower bow slides 1 and 2, respectively, ensuring balanced force distribution. When traveling on land, the left and right hydraulic struts 7 and 8 control the upper and lower bow skids 1 and 2 to form a certain angle, covering the front surface of the amphibious vehicle body. When traveling on water, the left and right hydraulic struts 7 and 8 extend, increasing the angle between the upper and lower bow skids 1 and 2, ultimately reaching 180°, that is, the two bow skids are spliced ​​together and remain in the same plane. To fix and limit the angle between the two bow skids, the left hydraulic strut 7 is connected to the bow skid via a left fixing structure 9, and the right hydraulic strut 8 is connected to the upper bow skid via a right fixing structure 10.

[0045] The upper bow skid 1 is a solid structure; the lower bow skid 2 is divided into two layers: the inner layer 5 is solid, and the outer layer 4 is hollow. A hole 3 is defined on the outer surface of the lower portion of the space. The amphibious vehicle body and the lower bow skid 2 are connected by a pipe 6. The connecting pipe is made of high-strength sealing materials and high-temperature resistant pipes to ensure the system's airtightness and stability. The injected gas is pumped through the ventilation pipe 6 into the hole 3 of the lower bow skid 2, forming supercavitation to reduce the resistance encountered by the amphibious vehicle during operation.

[0046] Furthermore, by setting a pressure regulating valve and a temperature control valve in front of the ventilation pipe connecting the bow skateboard and the vehicle body, it is ensured that the gas introduced has the conditions to form supercavitation at the holes of the bow skateboard of the amphibious vehicle, thereby generating supercavitation and reducing the resistance encountered by the amphibious vehicle during underwater driving.

[0047] Cavitation flow is usually characterized by a dimensionless number, the cavitation number σ. The cavitation number represents the ratio of the difference between the local and cavity absolute pressures to the kinetic energy per unit volume flow.

[0048]

[0049] Where P0 is the reference pressure, P c is the cavity pressure, U ∞ is the free stream velocity and ρ is the mass density of the fluid.

[0050] When the cavitation number σ is less than 0.1, supercavitation can occur. Therefore, it is necessary to control the pressure and flow rate of the injected gas so as to form supercavitation around the holes on the underside of the bow skateboard of the amphibious vehicle and reduce the resistance encountered by the vehicle when sailing underwater.

[0051] The present invention utilizes the working process of the supercavitation amphibious vehicle body water navigation drag reduction device, such as Figure 4 As shown:

[0052] Step 1: After the engine exhaust gas passes through a filtering device to remove impurities and harmful gases contained in the exhaust gas, it is collected through an exhaust gas collection device.

[0053] Step 2: The compression unit in the compressed gas storage device compresses the processed gas and stores it in a compressed gas tank;

[0054] Step 3: When sailing on water, the gas in the compressed gas tank is expanded through the expansion heat exchange unit to expand the gas flow rate to reach the target pressure;

[0055] Step 4: Pass the gas through a constant temperature device to reduce gas temperature fluctuations and maintain a stable gas temperature;

[0056] Step 5: inject gas into the cavity of the lower bow slide 2 through the ventilation pipe 6, and guide the gas through the cavity to the hole 3;

[0057] Step 6: Supercavitation is formed between the lower bow ski and the water body to reduce the resistance encountered by the amphibious vehicle when traveling underwater.

[0058] In step 1, the exhaust gas discharged by the engine enters the exhaust gas collection device through a pipeline, and harmful gases and impurities such as nitrogen oxides contained in the exhaust gas are removed by the filtering unit therein.

[0059] The compression unit in step 2 is mainly composed of a compressor. The compressor compresses the gas in the collection device and stores it in a compressed gas tank. The outlet of the compressed gas tank is connected through a pneumatic valve to control the flow of the exhaust gas to ensure that the gas pressure and flow meet the requirements.

[0060] The pressure released from the compressed gas tank in step 3 is controlled by a pneumatic control valve. The released gas flows through a pipeline into the expansion and heat exchange unit, which primarily consists of an expander. Compared to typical supercavitation applications, the flow rate required to form supercavitation on the bow ski of an amphibious vehicle is higher, requiring the expansion and heat exchange unit to increase the gas flow rate and control the exhaust gas pressure.

[0061] The constant temperature device in step 4 helps ensure the stability of gas flow and flow rate by maintaining the consistency of gas temperature, which helps to produce a more stable bubble layer and optimize the size and distribution of bubbles, thereby more effectively isolating the water and the vehicle surface and reducing resistance.

[0062] The above specific embodiments merely illustrate the design principles of the present invention. The shapes and names of the components described herein may vary and are not limiting. Therefore, those skilled in the art may modify or substitute equivalents for the technical solutions described in the above embodiments. Such modifications and substitutions, without departing from the inventive spirit and technical solutions of the present invention, shall fall within the scope of protection of the present invention.

Claims

1. A drag reduction device for an amphibious vehicle using supercavitation, characterized in that: include: Exhaust gas collection device, compressed gas storage device, expansion unit, constant temperature device, gas delivery assembly, supercavitation launch device; The exhaust gas collection device is used to collect and filter the exhaust gas generated by the amphibious vehicle engine; The compressed gas storage device is used to pressurize and store the filtered exhaust gas collected by the exhaust gas collection device through a compressor; The expansion unit is used to expand the gas in the compressed gas storage device to reduce the gas pressure and temperature when sailing on water; The constant temperature device is used to cool the depressurized gas and maintain the gas temperature within a certain range; The gas, which has been regulated in pressure and temperature, is sent to the supercavitation launch device through the gas delivery assembly; The supercavitation launcher is located at the bow of the amphibious vehicle and has a hole that emits pressure- and temperature-regulated gas outward, forming a supercavitation bubble around the hole for drag reduction. The supercavitation launch device comprises an upper bow slide (1) and a lower bow slide (2), which are not connected to each other; the upper bow slide (1) and the lower bow slide (2) are controlled to fold in a state by a hydraulic strut, and the folding state comprises the upper bow slide (1) and the lower bow slide (2) having an angle therebetween and covering the front surface of the amphibious vehicle body or unfolding in the same plane and docking; the upper bow slide (1) is a solid structure; the lower bow slide (2) is divided into an inner and outer layer, the inner layer being a solid structure and the outer layer being a hollow structure, and a hole is provided on the outer surface of the lower part of the space.

2. The amphibious vehicle water navigation drag reduction device using supercavitation as claimed in claim 1, characterized in that: The tail gas collecting device is provided with a filtering device to remove impurities and harmful gases contained in the tail gas.

3. The amphibious vehicle water navigation drag reduction device using supercavitation as claimed in claim 1, characterized in that: The compressed gas storage device compresses gas using a compression unit and stores the compressed gas in a compressed gas tank.

4. The amphibious vehicle water navigation drag reduction device using supercavitation as claimed in claim 3, characterized in that: The outlet of the compressed gas tank is connected via a pneumatic valve.

5. The amphibious vehicle water navigation drag reduction device using supercavitation as claimed in claim 1, characterized in that: When the vehicle is sailing on water, the expansion unit expands and exchanges heat on the gas in the compressed gas storage device through the expander, so that the pressure is reduced to the target pressure.

6. The amphibious vehicle water navigation drag reduction device using supercavitation as claimed in claim 1, characterized in that: The hydraulic strut is connected to the upper bow slide (1) via a fixed structure (9, 10) to fix and limit the unfolding angles of the upper bow slide (1) and the lower bow slide (2).

7. The amphibious vehicle water navigation drag reduction device using supercavitation as claimed in claim 1, characterized in that: The hydraulic support rod comprises a left hydraulic support rod (7) and a right hydraulic support rod (8).

8. The amphibious vehicle water navigation drag reduction device using supercavitation as claimed in claim 1, characterized in that: The gas delivery assembly is connected to the constant temperature device and the ventilation pipe of the supercavitation launch device. The ventilation pipe is a plurality of pipes evenly distributed at the bottom of the outer hollow structure of the lower bow slide (2) and provides the hollow structure with gas whose pressure and temperature are adjusted.

9. The amphibious vehicle water navigation drag reduction device using supercavitation as claimed in claim 8, characterized in that: The ventilation pipe is provided with a pressure regulating valve and a temperature control valve to ensure that the gas introduced has the conditions to form supercavitation at the holes of the bow skateboard of the amphibious vehicle.

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