A flow control device and method for improving ventilation cavitation stability

Abstract

The present invention discloses a flow control device and method for improving the stability of ventilation cavitation. The flow control device includes a cavitator, an air guide bowl, a ventilation pipeline, a spiral component, and a flow controller. The high-pressure airflow enters the interlayer through the air inlet along the ventilation pipeline and is finally discharged from the exhaust hole to form a vortex airflow, and impacts the spiral component to make it rotate around the supercavitating underwater vehicle. The present invention adds a flow control device to the traditional cavitator to make the gas in the cavitation rotate, and converts the internal energy of the high-pressure airflow into axial and tangential kinetic energy, thereby realizing active control of the cavitation morphology. The flow control method for improving the stability of ventilation cavitation can accelerate the generation rate of ventilation cavitation, inhibit the generation of liquid back jet flow in the cavitation, and the cavitation is rapidly generated until it wraps the entire underwater vehicle to form a supercavitation state, thereby greatly reducing the friction resistance on the surface of the underwater vehicle.

Description

Technical Field

[0001] The present invention relates to the technical field of underwater vehicle supercavitation technology, and in particular to a flow control device and method for improving the stability of ventilation cavitation. Background Art

[0002] With the continuous advancement of science and technology, it is derived from the subversive understanding of cavitation theory. It was previously believed that the cavitation phenomenon of propeller blades would reduce propulsion efficiency and the generation of cavitation should be suppressed. Later, it was found that the cavitation phenomenon that occurs when underwater vehicles sail at high speeds has shown excellent effects in reducing surface friction resistance, which has attracted extensive attention from researchers at home and abroad. After continuous and in-depth research and study, it has finally developed into artificial ventilation supercavitation technology. Its basic principle is to generate cavitation that stably wraps the vehicle through ventilation on the surface of the vehicle, so that the surface of the vehicle is isolated from the liquid medium, greatly reducing the friction resistance of the vehicle, and achieving a drag reduction rate of more than 90%. Supercavitation drag reduction technology completely changes the operation mode of underwater vehicles and will inevitably lead to technological changes in underwater transportation and weapon equipment.

[0003] However, the supercavitation formed by gas aggregation underwater has a very unstable side. Supercavitation vehicles will experience cavitation morphology oscillation, interface fluctuations, and even cavitation collapse in extreme cases, such as attitude changes during navigation and maneuvers, speed changes, changes in environmental pressure caused by changes in diving depth, eddy zones in the water, fish collisions, underwater near-free interface navigation, insufficient ventilation, excessive ventilation or uneven ventilation during entry and exit, and the influence of the suction effect of the tail jet, etc. The factors that cause cavitation instability can be roughly divided into two categories: parameter disturbances of the water flow environment outside the cavitation and disturbances of the fluid parameters inside the cavitation.

[0004] The hazards caused by supercavitation instability are also very obvious. The most direct harm is that it will change the dynamic characteristics of the navigation body and affect the stability of navigation. Secondly, the cavitation will generate extremely high instantaneous pressure during the oscillation or collapse process, which will damage the structure of the navigation body. Finally, there is a direct connection between the pressure pulsation in the cavitation and the gas noise. The noise problem caused by supercavitation instability will expose the existence of military targets and directly restrict the application of supercavitation technology in underwater weapons. It can be seen that the stability of supercavitation morphology is the premise and basis for ensuring the motion and dynamic stability of the navigation body with cavitation. Therefore, it is of great significance to study the flow control methods and devices that can improve the stability of cavitation.

[0005] Currently, the existing research on the problem of cavitation morphology stability mostly adopts the method of changing the shape of the cavitator and adjusting the ventilation flow rate. However, cavitation is prone to interface instability or even collapse under various complex disturbances such as external pressure fluctuations, tail jet disturbances and sudden increases in ventilation volume. How to improve the stability of the supercavitation morphology of underwater vehicles under complex disturbances is an issue that needs to be urgently addressed. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a flow control device and method for improving the stability of ventilation cavitation, by adding an axial spiral component to make the gas in the cavitation rotate, thereby achieving active control of the cavitation morphology and stability problems, and improving the stability of the supercavitation morphology of the underwater vehicle under complex disturbances.

[0007] In order to solve the above technical problems, the present invention is implemented by the following technical solutions: a flow control device for improving the stability of ventilation cavitation, comprising a cavitator detachably mounted on the head of a supercavitating underwater vehicle, and further comprising:

[0008] An air guide bowl, comprising a bowl body with an end fixedly connected to the cavitator, wherein the bowl body is a double-layer structure with a partition inside, wherein an air inlet hole is opened in the middle of the inner layer away from the cavitator, and a plurality of exhaust holes are evenly opened around the extension of the air inlet hole;

[0009] A ventilation pipeline, one end of which is fixedly connected to the inner layer of the bowl body, the other end of which is connected to an external high-pressure air flow source through a pipeline, and a spiral component is sleeved on the outer side of the middle part;

[0010] A spiral assembly, comprising a spiral sleeve sleeved on the outside of the ventilation pipeline and a plurality of spiral blades evenly arranged on the outside of the spiral sleeve;

[0011] The high-pressure airflow enters the partition through the air inlet along the ventilation pipeline and is finally discharged from the exhaust hole to form a vortex airflow, and impacts the spiral component to make it rotate around the supercavitating underwater vehicle.

[0012] Furthermore, the flow control device also includes a flow controller installed at the end of the ventilation pipeline away from the cavitator, which is used to adjust the total flow of the high-pressure airflow entering the ventilation pipeline.

[0013] Furthermore, the spiral component is installed inside the cavity of the air guide bowl.

[0014] Furthermore, the high-pressure airflow is the engine tail fuel gas jet gas.

[0015] Furthermore, the installation angle of the spiral blade relative to the horizontal plane is 15° to 45°.

[0016] Furthermore, the flow controller is a solenoid valve.

[0017] The present invention also provides a supercavitating underwater vehicle, comprising a vehicle body, an engine and a flow control device as described above, wherein the flow control device is fixedly connected to the vehicle body by welding, threading or bonding, and is coaxially arranged with the tail nozzle of the engine.

[0018] The present invention also provides a flow control method for improving the stability of ventilation cavitation bubbles, comprising the following steps:

[0019] S1, fixedly connecting the aforementioned flow control device to the main body of the navigation body;

[0020] S2, during navigation, a high-pressure airflow is introduced from the tail gas jet of the engine, enters the partition through the air inlet along the ventilation pipe and finally is discharged from the exhaust hole to form a swirling airflow;

[0021] S3, the high-pressure airflow discharged from the exhaust hole impacts the spiral component and causes it to rotate around the main body of the navigation body;

[0022] S4, the rotation of the spiral assembly drives the water-gas separation in the vicinity of the cavitator, accelerating the formation of cavitation until the entire supercavitating underwater vehicle is wrapped to form a supercavitating state;

[0023] S5, the rotation of the spiral component causes the gas in the cavitation to swirl, converting the internal energy of the high-pressure airflow into axial and tangential kinetic energy, thereby exerting active control on the cavitation morphology.

[0024] Furthermore, in step S2, when the high-pressure airflow is introduced, the flow controller outside the end of the ventilation pipeline is adjusted as needed to control the total flow of the high-pressure airflow.

[0025] Furthermore, in step S3, when the high-pressure airflow impacting the spiral assembly fails to reach the required swirl intensity, a motor is installed on one side of the cavitator to drive the spiral assembly to rotate, so as to enhance the swirling effect of the airflow around the underwater vehicle.

[0026] Compared with the prior art, the present invention is beneficial in that:

[0027] 1. The present invention adds a flow control device to the traditional cavitator to make the gas in the cavitation swirl, convert the internal energy of the high-pressure airflow into axial and tangential kinetic energy, thereby realizing active control of the cavitation morphology. By using the flow control device and method, the pressure pulsation of the ventilation cavitation under various disturbances can be significantly suppressed, the fluctuation and breakage of the cavitation interface can be improved, and the stability of the ventilation cavitation can be improved;

[0028] Second, the flow control device provided by the present invention fully utilizes the internal energy of the engine tail jet, and can achieve ventilation cavitation morphology and stability control without consuming additional energy;

[0029] 3. The supercavitating underwater vehicle provided by the present invention solves the problems that the shape of the supercavitating body generated by the conventional underwater vehicle carrying a fixed structure cavitator during acceleration does not match the shape of the underwater vehicle, the overall resistance is relatively large, the cavitation stability is poor, and the maneuverability is poor. The airflow in the cavitation can be swirled to enhance the ability of the cavitation to resist disturbances, improve the stability of the cavitation, and provide a guarantee for the high-speed and stable operation of the underwater vehicle. The structure is simple and practical.

[0030] 4. The flow control method for improving the stability of ventilation cavitation provided by the present invention introduces a high-pressure airflow from the tail gas jet of the supercavitating underwater vehicle, enters the interlayer through the air inlet along the ventilation pipeline and is finally discharged from the exhaust hole to form a swirling airflow, and impacts the spiral component to make it rotate around the supercavitating underwater vehicle. The rotation of the spiral component drives the separation of water and gas in the area near the cavitator, and the central low-pressure area is conducive to the aggregation of bubbles, which can accelerate the generation rate of ventilation cavitation and inhibit the generation of liquid back jet in the cavitation. The cavitation is rapidly generated until it wraps the entire underwater vehicle to form a supercavitation state, thereby greatly reducing the friction resistance on the surface of the underwater vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0032] The present invention is further described below in conjunction with the accompanying drawings:

[0033] Figure 1 It is a schematic structural diagram of a flow control device for improving the stability of ventilation cavitation bubbles according to the present invention;

[0034] Figure 2 yes Figure 1 A full cross-sectional view of

[0035] Figure 3 is a top view of the gas guide bowl of the present invention;

[0036] Figure 4 yes Figure 3 A full cross-sectional view of

[0037] Figure 5 is a schematic structural diagram of the spiral assembly of the present invention;

[0038] Figure 6 is a diagram of the use state of the flow control device of the present invention;

[0039] 1. Cavitation device; 2. Air guide bowl; 3. Ventilation pipe; 4. Spiral assembly; 5. Flow controller; 21. Bowl body; 22. Air inlet hole; 23. Exhaust hole; 24. Interlayer; 41. Spiral sleeve; 42. Spiral blade. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0042] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0043] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0044] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0045] Embodiment 1

[0046] As attached Figure 1-2 A flow control device for improving the stability of ventilation cavitation is shown. The gas in the cavitation is swirled by the cooperation of various components, so as to achieve active control of the cavitation morphology and stability. The device mainly includes a cavitator 1, a gas guide bowl 2, a ventilation pipeline 3, a spiral component 4, and a flow controller 5 which are interconnected, wherein:

[0047] The cavitator 1 is detachably mounted on the head of the supercavitating underwater vehicle and is a conventional cavitator structure, which will not be described in detail here. The present invention improves the conventional cavitator to make the gas in the cavitation swirl, thereby converting the internal energy of the high-pressure airflow into axial and tangential kinetic energy.

[0048] Gas bowl 2, as attached Figure 3-4 As shown, it comprises a bowl body 21 whose end is fixedly connected to the cavitator 1, the bowl body 21 is a double-layer structure with a partition 24 inside, and the partition 24 plays a role of buffering the high-pressure airflow, wherein an air inlet 22 is opened in the middle of the inner layer away from the cavitator 1, and a plurality of exhaust holes 23 are uniformly opened around the extension of the air inlet 22;

[0049] The ventilation pipeline 3 has one end fixedly connected to the inner layer of the bowl body 21, and the other end connected to the external high-pressure airflow source through a pipeline, and a spiral component 4 is sleeved on the outer side of the middle part. In this embodiment, the high-pressure airflow source is the engine tail jet gas of the supercavitating underwater vehicle. The gas is a non-condensable gas, which makes full use of the internal energy of the engine tail jet gas, does not consume additional energy, realizes the ventilation cavitation morphology and stability control, and saves energy;

[0050] The spiral assembly 4 is installed inside the cavity of the gas guide bowl 2, as shown in the attached Figure 5 As shown, it comprises a spiral sleeve 41 sleeved on the outside of the ventilation pipe 3 and a plurality of spiral blades 42 evenly arranged on the outside of the spiral sleeve 41, and the installation angle of the spiral blades 42 relative to the horizontal plane is in the range of 15° to 45°, and in this embodiment, it is further preferably 30°;

[0051] A flow controller 5, used for regulating the total flow of the high-pressure airflow entering the ventilation pipeline 3, is installed at the end of the ventilation pipeline 3 away from the cavitator 1. In this embodiment, the flow controller 5 is a solenoid valve;

[0052] The high-pressure airflow enters the partition 24 through the air inlet 22 along the ventilation pipe 3 for buffering and finally is discharged from the exhaust hole 23 to form a vortex airflow, and impacts the spiral component 4 to make it rotate around the supercavitating underwater vehicle.

[0053] The flow control device used to improve the stability of ventilation cavitation has the following characteristics: first, rotation is conducive to water-gas separation, can accelerate the generation of cavitation during the generation process of ventilation cavitation, and inhibit the generation of liquid back jet in the cavitation; second, when the air flow rotation reaches a certain intensity, the tangential velocity increases, and a negative pressure gradient appears in the central axial direction, which actively enhances the gas backflow intensity in the cavitation; third, the swirl can reduce turbulent pulsation to a certain extent, reduce parameter fluctuations when the cavitation is disturbed, thereby inhibiting interface fluctuations.

[0054] In another embodiment of the present invention, a multi-stage flow control device may be added to enhance the swirling effect of the ventilation cavitation bubble.

[0055] Embodiment 2

[0056] The present invention further provides a supercavitating underwater vehicle based on Example 1, which solves the problems of the supercavitating shape generated by the traditional underwater vehicle carrying a fixed structure cavitator during the acceleration process not matching the shape of the underwater vehicle, the overall resistance is relatively large, the cavitation stability is poor, and the maneuverability is poor. The supercavitating underwater vehicle comprises a vehicle body, an engine, and a flow control device as described in Example 1. The flow control device is fixedly connected to the vehicle body by welding, threaded connection or bonding, and is coaxially arranged with the tail nozzle of the engine.

[0057] The supercavitating underwater vehicle described in this embodiment adopts the flow control device described in Example 1. The vortex of the airflow in the cavitation can enhance the ability of the cavitation to resist disturbances, improve the stability of the cavitation, and provide a guarantee for the high-speed and stable operation of the underwater vehicle.

[0058] Embodiment 3

[0059] The present invention further provides a flow control method for improving the stability of ventilation cavitation bubbles based on the first embodiment, that is, the use process of the flow control device described in the first embodiment, comprising the following steps:

[0060] S1, the flow control device described in the first embodiment is fixedly connected to the main body of the navigation body, which can be fixedly connected by any method of welding, threading or bonding;

[0061] S2, during navigation, if Figure 6 As shown, a high-pressure airflow is introduced from the tail gas jet of the engine, enters the partition 24 through the air inlet 22 along the ventilation pipe 3 for buffering and finally discharged from the exhaust hole 23, and a swirling airflow is formed under the action of the spiral component 4;

[0062] S3, the high-pressure airflow discharged from the exhaust hole 23 impacts the spiral component 4 and causes it to rotate around the main body of the navigation body;

[0063] S4, the spiral assembly 4 rotates to drive the water-gas separation in the vicinity of the cavitator 1, accelerates the cavitation generation until the entire supercavitating underwater vehicle is wrapped to form a supercavitating state and inhibit the generation of the liquid back jet in the cavitation;

[0064] S5, the spiral component 4 rotates to make the gas in the cavitation swirl, so as to enhance the ability of the cavitation to resist disturbance, improve the stability of the cavitation, and convert the internal energy of the high-pressure airflow into axial and tangential kinetic energy, thereby exerting active control on the cavitation morphology.

[0065] Preferably, in step S2, when introducing the high-pressure airflow, the flow controller 5 on the outer side of the end of the ventilation pipeline 3 is adjusted as needed to adjust the total flow of the high-pressure airflow. The flow controller 5 is used to cooperate to achieve the purpose of fine flow control of the cavitation morphology. The cavitation shape can be roughly adjusted to meet the needs, because the larger the shape of the cavitation means the greater the cavitation resistance, and the larger the ventilation flow will cause unnecessary energy loss.

[0066] Preferably, in step S3, when the high-pressure airflow impacting the spiral assembly 4 fails to reach the required swirl intensity, a motor is installed on one side of the cavitator 1 to drive the spiral assembly 4 to rotate, so as to enhance the swirl effect of the airflow around the underwater vehicle and realize continuous adjustment of the rotation speed of the spiral blades 42, thereby achieving the purpose of fine flow control.

[0067] The flow control method described in this embodiment takes into account that the generation and collapse of artificial ventilation cavitation bubbles is essentially a process of flow separation and reattachment. Here, relatively mature methods such as wing boundary layer control and rotational mixing combustion in the field of aerodynamics are borrowed and applied to underwater supercavitation technology. A high-pressure airflow is introduced from the tail gas jet of the supercavitating underwater vehicle, and enters the partition 24 through the air inlet 22 along the ventilation pipeline 3 and is finally discharged from the exhaust hole 23 to form a swirling airflow, and impacts the spiral component 4 to make it rotate around the main body of the vehicle. The rotation of the spiral component 4 drives the separation of water and gas in the area near the cavitator, and the central low-pressure area is conducive to the aggregation of bubbles, which can accelerate the generation rate of ventilation cavitation and inhibit the generation of liquid back jet in the cavitation. The cavitation is rapidly generated until it wraps the entire underwater vehicle to form a supercavitation state, thereby greatly reducing the friction resistance on the surface of the underwater vehicle.

[0068] Embodiment 4

[0069] The present invention also provides another flow control method for improving the stability of ventilation cavitation. This method introduces high-pressure airflow from the tail gas jet of the supercavitating underwater vehicle, and uses tangential air intake to achieve swirling of the airflow in the cavitation, thereby increasing the reflow intensity in the cavitation, thereby achieving active control of the cavitation morphology and stability issues, improving the cavitation's ability to resist disturbances, and improving stability.

[0070] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A flow control device for improving the stability of a ventilated cavitation bubble, comprising a cavitator (1) detachably mounted on the head of a supercavitating underwater vehicle, It is characterized in that Also includes: An air guide bowl (2) comprises a bowl body (21) whose end is fixedly connected to the cavitator (1), the bowl body (21) being a double-layer structure having a partition (24) inside, wherein an air inlet hole (22) is provided in the middle of the inner layer away from the cavitator (1), and a plurality of air outlet holes (23) are uniformly provided around the outer extension of the air inlet hole (22); A ventilation pipeline (3), one end of which is fixedly connected to the inner layer of the bowl body (21), the other end of which is connected to an external high-pressure air flow source through a pipeline, and the outer side of the middle part is sleeved with a spiral component (4); A spiral assembly (4) comprising a spiral sleeve (41) sleeved on the outside of the ventilation pipeline (3) and a plurality of spiral blades (42) evenly arranged on the outside of the spiral sleeve (41); The high-pressure airflow flows along the ventilation pipeline (3) through the air inlet (22) into the partition (24) and finally is discharged from the air outlet (23) to form a swirling airflow, and impacts the spiral component (4) to make it rotate around the supercavitating underwater vehicle; The flow control device further comprises a flow controller (5) installed at an end of the ventilation pipeline (3) away from the cavitator (1), and used for regulating the total flow of the high-pressure airflow entering the ventilation pipeline (3); The spiral component (4) is installed inside the cavity of the air guide bowl (2); The high-pressure airflow is the engine tail fuel gas jet gas; The installation angle of the spiral blade (42) relative to the horizontal plane is 15° to 45°.

2. A flow control device for improving the stability of ventilation cavitation bubbles according to claim 1, Features: The flow controller (5) is a solenoid valve.

3. A supercavitating underwater vehicle, Features: It comprises a navigation body, an engine and a flow control device as described in claim 1 or 2, wherein the flow control device is fixedly connected to the navigation body by welding, threading or bonding, and is coaxially arranged with the tail nozzle of the engine.

4. A flow control method for improving the stability of ventilation cavitation bubbles, It is characterized in that The following steps are involved: S1, fixedly connecting the flow control device according to claim 1 or 2 to the main body of the navigation body; S2, during navigation, a high-pressure airflow is introduced from the tail gas jet of the engine, enters the partition (24) through the air inlet (22) along the ventilation pipeline (3) and is finally discharged from the exhaust hole (23) to form a swirling airflow; S3, the high-pressure airflow discharged from the exhaust hole (23) impacts the spiral component (4) and causes it to rotate around the main body of the navigation body; S4, the spiral assembly (4) rotates to drive the water and gas separation in the vicinity of the cavitator (1), accelerating the generation of cavitation bubbles until the entire supercavitating underwater vehicle is enveloped to form a supercavitating state; S5, the spiral component (4) rotates to cause the gas in the cavitation to swirl, converting the internal energy of the high-pressure airflow into axial and tangential kinetic energy, thereby exerting active control on the cavitation morphology.

5. A flow control method for improving ventilation cavitation stability according to claim 4, Features: In step S2, when the high-pressure airflow is introduced, the flow controller (5) outside the end of the ventilation pipeline (3) is adjusted as needed to control the total flow of the high-pressure airflow.

6. A flow control method for improving ventilation cavitation stability according to claim 5, Features: In step S3, when the high-pressure airflow impacting the spiral assembly (4) fails to reach the required swirl intensity, a motor is installed on one side of the cavitator (1) to drive the spiral assembly (4) to rotate, so as to enhance the swirl effect of the airflow around the underwater vehicle.

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