Jet resistance reduction device for small waterplane area catamaran and control method

Abstract

The invention discloses a small waterplane area catamaran jet resistance reduction device and a control method, the device comprises a catamaran body and an air compressor arranged on the catamaran body, and the catamaran body comprises an upper body located above the water surface and a submerged body in contact with the water body; the exhaust ring pipes are arranged on the periphery of the submerged body at intervals and used for forming a gas interlayer on the periphery of the submerged body, the density sensor is used for detecting the density of fluid on different surfaces of the submerged body, each exhaust ring pipe is of an annular structure, and a plurality of exhaust holes are formed in the end, facing the tail of the submerged body, of each exhaust ring pipe; an inner cavity of each exhaust ring pipe is divided into an upper exhaust chamber and a lower exhaust chamber which are independent, and the two exhaust chambers of the two exhaust ring pipes are communicated with an air compressor. The upper and lower independent gas interlayers are formed on the outer surface of the submerged body, the situation that the effect of the gas interlayers is not ideal due to the pressure difference of the underwater submerged body and the movement of the ship body is avoided, and the overall drag reduction efficiency can be improved.

Description

Technical Field

[0001] The present invention relates to a jet drag reduction device, in particular to a jet drag reduction device for a small waterplane area catamaran and a control method thereof. Background Art

[0002] Small waterplane area catamarans mainly reduce the designed waterline area so that most of the displacement volume is moved to a depth away from the water surface line to reduce the wave disturbance force (moment) of the ship's movement. Its Froude number is generally 0.7-1 during navigation. At the same time, it will bring corresponding problems: due to the large wet surface area of ​​the underwater submersible, the frictional resistance is large during high-speed navigation, which will cause serious energy consumption during high-speed navigation and other problems.

[0003] Existing technologies generally use bubble drag reduction or air layer drag reduction to reduce frictional resistance during navigation. However, there are relatively few drag reduction technologies specifically designed for small waterplane area catamarans (SWATs). Bubble drag reduction achieves drag reduction by forming tiny bubbles on the hull surface. However, as the hull moves backward away from the bubble generator during navigation, the tiny bubbles will form larger bubbles, making it difficult to achieve the desired drag reduction effect. Air layer drag reduction achieves drag reduction by forming an air layer on the hull surface. However, when existing air layer drag reduction technologies are actually applied, it is difficult to form a complete air layer on the hull surface, and it is also difficult to achieve the desired drag reduction effect. Summary of the Invention

[0004] Purpose of the invention: The first purpose of the present invention is to provide a small waterplane area catamaran jet drag reduction device with good drag reduction effect.

[0005] The second object of the present invention is to provide a control method for a small waterplane area catamaran jet drag reduction device.

[0006] Technical solution: The present invention discloses a jet drag reduction device for a small waterplane area catamaran, comprising a hull and an air compressor arranged on the hull, wherein the hull comprises an upper body located above the water surface and a submerged body in contact with the water body; and further comprises at least two groups of exhaust ring pipes alternately arranged at the periphery of the submerged body and used to form a gas barrier at the periphery of the submerged body, and a density sensor for detecting the fluid density at different surfaces of the submerged body, wherein the exhaust ring pipe is arranged in an annular structure, and a plurality of exhaust holes are opened at one end of the exhaust ring pipe toward the tail of the submerged body, and the inner cavity of the exhaust ring pipe is divided into two independent upper and lower exhaust chambers, and the two exhaust chambers of the two exhaust ring pipes are respectively connected to the air compressor.

[0007] Furthermore, a diverter box connected to the air compressor is provided inside the submerged body for diverting compressed gas, and the diverter box is provided with multiple diverter holes that can achieve different exhaust flow rates, and the two exhaust chambers of the two exhaust ring pipes are respectively connected to different diverter holes.

[0008] Furthermore, the diversion box includes three upper chambers independently arranged from top to bottom for diverting the gas, a middle chamber for storing the diverted gas, and a lower chamber for regulating the flow rate of the gas when it is discharged from the diversion hole.

[0009] Furthermore, a plurality of diversion boxes are fixedly installed inside the upper chamber, and the plurality of diversion boxes are distributed in a circular array with the center points of the upper chambers, and ventilation holes for gas to enter the diversion boxes are opened in the direction of the vertical center axis of the diversion box; a sealing plate is fixedly installed on the inner wall of the middle chamber, which divides its inner cavity into a plurality of independent gas storage chambers, the number and positions of the gas storage chambers are adapted to the diversion box bodies, and ventilation channels are opened between the diversion box bodies corresponding to the gas storage chambers to connect the two; the diversion holes are arranged at the bottom of the diversion box, and the number and positions of the diversion holes are adapted to the diversion box bodies, a diversion air pipe connected to the gas storage chamber and the corresponding diversion holes is installed in the lower chamber, and an electric ball valve for controlling the gas flow and a flow monitor for monitoring the gas flow are installed on the diversion air pipe.

[0010] Furthermore, a rectifying orifice plate for diversion is installed in the diversion box body; the edges of two adjacent diversion box bodies are adhered and fixedly connected, and the top and bottom plates of the diversion box bodies are adhered and fixedly connected to the inner wall of the upper chamber.

[0011] Furthermore, a bracket is fixedly connected to the outer periphery of the diversion box, and one end of the bracket away from the diversion box is fixedly connected to the inner wall of the submersible body.

[0012] Furthermore, the outer surface of the exhaust ring tube is set to a conical surface, and the diameter of the exhaust pipe gradually increases from the head of the submersible body to the tail of the submersible body; the exhaust hole is set to a conical shape, and the diameter of the exhaust hole gradually increases from the head of the submersible body to the tail of the submersible body, and there is a certain distance between the exhaust hole and the submersible body.

[0013] Furthermore, a plurality of density sensors are provided, and the density sensors are symmetrically mounted on the upper and lower surfaces of the submersible body, and the density sensors are located on the side of the exhaust ring pipe facing the tail of the submersible body.

[0014] Based on the same inventive concept, the present invention also discloses a control method for a small waterplane area catamaran jet drag reduction device, comprising the following steps:

[0015] S1: Start the air compressor, and the compressed gas enters the two independent exhaust chambers of the two exhaust ring pipes after being diverted by the diverter box. The gas discharged through the exhaust chamber above the exhaust ring pipe near the head of the submersible body forms a first gas barrier on the upper surface of the middle part of the submersible body, the gas discharged through the exhaust chamber above the exhaust ring pipe near the head of the submersible body forms a second gas barrier on the lower surface of the middle part of the submersible body, the gas discharged through the exhaust chamber above the exhaust ring pipe near the tail of the submersible body forms a third gas barrier on the upper surface of the tail of the submersible body, and the gas discharged through the exhaust chamber above the exhaust ring pipe near the tail of the submersible body forms a fourth gas barrier on the lower surface of the tail of the submersible body;

[0016] S2: Gas density sensors symmetrically arranged on one side of the two exhaust ring pipes detect the fluid density at the first gas barrier layer, the second gas barrier layer, the third gas barrier layer, and the fourth gas barrier layer respectively;

[0017] S3: Determine whether the fluid density at the first gas barrier layer, the second gas barrier layer, the third gas barrier layer, and the fourth gas barrier layer reaches a preset value. If the fluid density at a certain gas barrier layer reaches the preset value, maintain the current state of the gas barrier layer. If the fluid density at a certain gas barrier layer is lower than the preset value, adjust the gas flow rate discharged from the exhaust chamber corresponding to the gas barrier layer until the fluid density at the gas barrier layer of the gas barrier layer reaches the preset value.

[0018] Furthermore, the method for adjusting the gas flow discharged from the exhaust chamber in real time is: adjusting the air compressor connected to the exhaust chamber or the electric ball valve on the diversion air pipe corresponding to the diversion hole connected to the exhaust chamber to control the gas flow discharged from the exhaust chamber, and the flow monitor monitors the gas flow discharged from the corresponding diversion air pipe in real time.

[0019] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: The present invention forms upper and lower independent gas barriers on the outer surface of the submerged body, which is beneficial to reducing the friction resistance caused by the wet surface of the submerged body, thereby reducing the energy consumption of the hull during navigation. The inner cavity of the exhaust ring pipe of the present invention is divided into two upper and lower independent exhaust chambers, which can independently control the gas barriers on the upper and lower surfaces of the submerged body, and facilitate the adjustment of the gas barriers on the upper and lower surfaces of the submerged body according to actual conditions, thereby avoiding the unsatisfactory gas barrier effect caused by the underwater submerged body pressure difference and the movement of the hull, and is beneficial to improving the overall drag reduction efficiency. The present invention arranges the front and rear exhaust ring pipes alternately on the outer periphery of the submerged body. The cooperation of the two exhaust ring pipes can effectively prevent the gas barrier from breaking in the middle or tail of the submerged body. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is the front view of the present invention;

[0021] Figure 2 It is a left side view of the hull of the present invention;

[0022] Figure 3 is a cross-sectional view of the present invention;

[0023] Figure 4 is a cross-sectional view of the diverter box of the present invention;

[0024] Figure 5 is a cross-sectional view of the upper chamber of the diverter box of the present invention;

[0025] Figure 6 A bottom view of the diverter box of the present invention;

[0026] Figure 7 is a cross-sectional view of a submerged body of the present invention;

[0027] Figure 8 is an enlarged view of the exhaust ring pipe of the present invention;

[0028] Figure 9 Another enlarged view of the exhaust ring pipe of the present invention;

[0029] Figure 10 is a flow chart of an embodiment of the present invention. DETAILED DESCRIPTION

[0030] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0031] Example 1

[0032] The present invention discloses a small waterplane area catamaran jet drag reduction device, such as Figures 1 to 3 As shown, it includes a hull, an air compressor 1 installed on the hull, an exhaust ring pipe 6 and a density sensor 7. The hull is composed of an upper body 2, a submerged body 3 and pillars 4 connected between the upper body 2 and the submerged body 3. The upper body 2 is located above the water surface and the submerged body 3 is in contact with the water. The air compressor 1 is fixedly installed inside the upper body 2. Figure 1 、 Figure 3 、 Figure 8 and Figure 9As shown, there are at least two groups of exhaust ring pipes 6, and the two groups of exhaust ring pipes 6 are alternately installed on the outer periphery of the submerged body 3. The exhaust ring pipes 6 are arranged in a ring structure, and a plurality of exhaust holes 9 are opened at one end of the exhaust ring pipe 6 facing the tail of the submerged body 3, and the inner cavity of the exhaust ring pipe 6 is divided into two independent exhaust chambers 10 above and below. The two exhaust chambers 10 of the two exhaust ring pipes 6 are respectively connected to the air compressor 1, and finally the gas is discharged from the exhaust hole 9 and forms an air barrier on the surface of the submerged body 3. By adjusting the output of the air compressor 1, the gas flow discharged from different exhaust chambers 10 is controlled. In actual use, the air compressor 1 can be connected to different exhaust chambers 10 respectively through a multi-way valve and a connecting pipe. The gas flow discharged from the corresponding exhaust chamber 10 can be adjusted by adjusting the corresponding valve. Preferably, when the exhaust ring pipes 6 are set as two groups, one group of exhaust ring pipes 6 is installed at the transition position between the conical surface and the cylindrical surface of the head of the submersible 3, the other group of exhaust ring pipes is installed between the transition position of the head and the transition position of the tail of the submersible 3, and the other group of exhaust ring pipes is installed at the position of 1 / 10 to 6 / 10 from the head to the tail of the cylindrical surface of the submersible 3.

[0033] Preferably, the small waterplane area catamaran jet drag reduction device further comprises a diverter box 5, which is mounted inside the submerged body 3, and a bracket 19 is fixedly connected to the periphery of the diverter box 5, and one end of the bracket 19 away from the diverter box 5 is fixedly connected to the inner wall of the submerged body 3, and an air inlet is provided on the top of the diverter box 5, such as Figure 4 and Figure 6 As shown, the bottom of the diverter box 5 is provided with a plurality of diverter holes 8 capable of achieving different exhaust flow rates, and the air inlet is connected to the air compressor 1 via a vent pipe 20. The diverter box 5 diverts the gas compressed by the air compressor 1, and the diverted gas is discharged from different diverter holes 8. The two exhaust chambers 10 of the two exhaust ring pipes 6 are respectively connected to different diverter holes 8. After being diverted by the diverter box 5, the gas compressed by the air compressor 1 enters the exhaust chamber of the corresponding exhaust ring pipe 6 from different diverter holes 8, and is finally discharged from the exhaust hole 9 and forms an air barrier on the surface of the submerged body 3.

[0034] When the small waterplane area catamaran is sailing at high speed, the wet area of ​​the submerged body 3 is large due to its location in the water body, and the friction resistance accounts for the vast majority of the total resistance. The present invention forms an air layer barrier on the outer surface of the submerged body 3, and utilizes the physical properties of water and air such as density and viscosity to effectively reduce the friction resistance of the hull during navigation; due to the changes in the navigation posture of the small waterplane area catamaran and the influence of wind, waves and currents on the movement of the ship, an air flow distribution method is adopted in which two groups of exhaust ring pipes 6 arranged alternately in the front and rear cooperate with each other. When the movement amplitude of the submerged body 3 is too large, resulting in the rupture of the gas barrier in the middle of the submerged body 3, the exhaust ring pipe 6 near the tail of the submerged body 3 can replenish the broken air layer in time, thereby improving the overall gas barrier coverage rate. The exhaust ring pipe 6 adopts a strategy of controlling the air flow separately in the upper and lower parts, mainly because the density difference between air and water is large, the gas barrier will float up, resulting in a decrease in the gas barrier coverage rate on the upper surface of the submersible 3. The strategy of separately controlling the upper and lower air flows formed by the upper and lower independent exhaust chambers 10 of the exhaust ring pipe 6 is conducive to adjusting the distribution of the upper and lower air flows according to actual working conditions and improving the coverage rate of the gas barrier; that is, it avoids the situation where the pressure difference between the underwater submersible 3 and the surface submersible 3 and the unsatisfactory gas barrier effect caused by the movement of the hull.

[0035] like Figure 1 and Figure 3 As shown, a density sensor 7 is mounted on the outer surface of the submerged body 3 and is used to detect the density of the fluid on the surface of the submerged body 3. Multiple density sensors 7 are provided, and the density sensors 7 are symmetrically mounted on the upper and lower surfaces of the submerged body 3, and the density sensors 7 are located on the side of the exhaust ring pipe 6 facing the tail of the submerged body 3. Preferably, at least four density sensors 7 are provided, and the four density sensors 7 are respectively mounted on one side of the four exhaust chambers 10. The four density sensors 7 are used to detect the fluid density at the air barrier generated by the four exhaust chambers 10, and indirectly determine the gas proportion in the air barrier by the fluid density, so as to facilitate the subsequent control of the exhaust flow of the air compressor 1 connected to the exhaust chamber 10 or the diverter hole 8 connected to the exhaust chamber 10, thereby adjusting the generated air barrier. For example, the gas flow of the exhaust ring pipe 6 near the head of the submerged body 3 is increased to prevent the submerged body 3 from moving too much and causing the gas barrier to break in the middle of the submerged body 3; for example, the gas flow of the exhaust chamber 10 above the two exhaust ring pipes 6 is increased to avoid the situation where the gas barrier coverage rate on the upper surface of the submerged body 3 is reduced due to the large density difference between air and water. In actual use, the air compressor 1 and the density sensor 7 can be electrically connected to the controller of the hull or another controller to facilitate the staff to control the gas barrier on the surface of the submerged body 3.

[0036] like Figure 4As shown, the diverter box 5 includes three independently arranged upper chambers for diverting the gas, a middle chamber for storing the diverted gas, and a lower chamber for regulating the flow rate of the gas when it is discharged from the diverter hole 8. A plurality of diversion box bodies 11 are fixedly installed inside the upper chamber and are distributed in a circular array with the center point of the upper chamber, and a plurality of diversion box bodies 11 are provided with air vents 12 for gas to enter the diversion box body 11 in the direction of the vertical center axis of the diversion box 5. The gas entering from the air inlet on the top of the diversion box 5 enters different diversion box bodies 11 through different air vents 12 to realize gas diversion; preferably, a rectifying orifice plate 18 for diversion is installed in the diversion box body 11, and the rectifying orifice plate 18 is conducive to uniformly introducing the compressed gas into the gas storage chamber 14; the edges of two adjacent diversion box bodies 11 are adhered and fixedly connected, and the top and bottom plates of the diversion box body 11 are adhered and fixedly connected to the inner wall of the upper chamber. This arrangement can prevent gas leakage during the diversion process. A sealing plate 13 is fixedly mounted on the inner wall of the intermediate chamber, dividing its interior into multiple independent air storage chambers 14. The number and position of air storage chambers 14 are compatible with the diversion box body 11, and a ventilation channel is provided between the corresponding diversion box bodies 11, connecting the two. The diverted gas is stored in the corresponding air storage chamber 14. A diversion air pipe 15 is installed in the lower chamber, connecting the air storage chamber 14 and the corresponding diversion holes 8. The diversion air pipe 15 is also equipped with an electric ball valve 16 for controlling the gas flow and a flow monitor 17 for monitoring the gas flow. The number of diversion holes 8 matches the number of diversion pipes 15, and the bottom of the diversion air pipe 15 is connected to the corresponding diversion holes 8. The number and position of the diversion holes 8 are compatible with the diversion box body 11. In actual use, the air compressor 1, density sensor 7, electric ball valve 16, and flow monitor 17 can be electrically connected to the hull controller or another controller to facilitate personnel to control the gas barrier on the surface of the submerged body 3.

[0037] Preferably, Figure 8 As shown, the outer surface of the exhaust ring pipe 6 is set to a conical surface, and the diameter of the exhaust pipe gradually increases from the head of the submerged body 3 to the tail of the submerged body 3; the setting of the conical surface of the exhaust ring pipe 6 is conducive to reducing the resistance caused by the exhaust ring pipe 6 itself. Figure 9 As shown, the exhaust hole 9 is set to be conical, and the diameter of the exhaust hole 9 gradually increases from the head of the submerged body 3 to the tail of the submerged body 3. The conical setting of the exhaust hole 9 allows the gas ejected from the exhaust hole 9 to better fit the surface of the submerged body 3; and there is a certain distance between the exhaust hole 9 and the submerged body 3; this distance is conducive to the formation of a negative pressure area behind the exhaust hole 9, which can effectively prevent the incoming flow from affecting the formation of the gas barrier. The existence of the negative pressure area can effectively increase the coverage area of ​​the gas barrier on the surface of the submerged body 3.

[0038] Example 2

[0039] The present invention discloses a control method for a small waterplane area catamaran jet drag reduction device, which is characterized by comprising the following steps:

[0040] S1: Start the air compressor 1. The compressed gas is diverted by the diverter box 5 and enters the two independent exhaust chambers 10 of the two exhaust ring pipes 6 respectively. The gas discharged through the exhaust chamber 10 above the exhaust ring pipe 6 near the head of the submersible 3 forms a first gas barrier on the upper surface of the middle part of the submersible 3, the gas discharged through the exhaust chamber 10 above the exhaust ring pipe 6 near the head of the submersible 3 forms a second gas barrier on the lower surface of the middle part of the submersible 3, the gas discharged through the exhaust chamber 10 above the exhaust ring pipe 6 near the tail of the submersible 3 forms a third gas barrier on the upper surface of the tail of the submersible 3, and the gas discharged through the exhaust chamber 10 above the exhaust ring pipe 6 near the tail of the submersible 3 forms a fourth gas barrier on the lower surface of the tail of the submersible 3.

[0041] S2: The gas density sensors 7 symmetrically arranged on one side of the two exhaust ring pipes 6 detect the fluid density at the first gas barrier layer, the second gas barrier layer, the third gas barrier layer and the fourth gas barrier layer respectively.

[0042] S3: Determine whether the fluid density at the first, second, third, and fourth gas barriers reaches a preset value. If the fluid density at a particular gas barrier reaches the preset value, maintain the current state of the gas barrier. If the fluid density at a particular gas barrier is lower than the preset value, adjust the gas flow rate discharged from the corresponding exhaust chamber 10 until the fluid density at the gas barrier of the gas barrier reaches the preset value. The method for adjusting the gas flow rate discharged from the exhaust chamber 10 is to adjust the electric ball valve 16 on the diversion air pipe 15 corresponding to the air compressor 1 connected to the exhaust chamber 10 or the diversion hole 8 connected to the exhaust chamber 10 to control the gas flow rate discharged from the exhaust chamber 10. The flow rate monitor 17 monitors the gas flow rate discharged from the corresponding diversion air pipe 15 in real time. If the air compressor 1 is connected to multiple exhaust chambers 10, the gas flow rate can be directly obtained through the air compressor 1, or an air flow control and monitoring device can be installed on the multi-way valve of the air compressor 1. In actual use, the air compressor 1, density sensor 7, electric ball valve 16 and flow monitor 17 can be electrically connected to the hull controller or another controller to facilitate the staff to control the gas barrier on the surface of the submerged body 3. The steps of controlling the gas barrier are as follows: Figure 10 The flowchart is shown in FIG.

[0043] When the small waterplane area catamaran is sailing at high speed, due to the large wet area of ​​the submerged body 3 and the fact that frictional resistance accounts for the vast majority of the total resistance, the gas barrier formed on the surface of the submerged body 3 can effectively reduce the frictional resistance. Due to the changes in the navigation posture of the small waterplane area catamaran and the influence of wind, waves and currents on the movement of the ship, the airflow distribution method in which the front and rear two sets of exhaust ring pipes 6 cooperate with each other can effectively prevent the situation in which the gas barrier breaks in the middle of the submerged body 3 due to excessive movement of the submerged body 3. The exhaust ring pipe 6 in the rear row can replenish the broken gas barrier in time and improve the overall air layer coverage. The exhaust ring pipe 6 adopts a control strategy of regulating the gas flow rate by using two independent upper and lower exhaust chambers 10. This is mainly due to the large difference in density between air and water. The gas layer will float up, resulting in a decrease in the gas barrier coverage rate on the upper surface of the submerged body 3. The upper and lower airflow rates are controlled separately, and the distribution of the upper and lower airflow rates is adjusted according to the actual working conditions to improve the coverage rate of the air layer.

Claims

1. A jet drag reduction device for a small waterplane area catamaran, comprising a hull and an air compressor (1) arranged on the hull, wherein the hull comprises an upper body (2) located above the water surface and a submerged body (3) in contact with the water; characterized in that: The invention also includes at least two groups of exhaust ring pipes (6) arranged alternately on the periphery of the submerged body (3) and used to form a gas barrier layer on the periphery of the submerged body (3), and a density sensor (7) for detecting the density of the fluid at different surfaces of the submerged body (3). The exhaust ring pipe (6) is arranged in an annular structure, and a plurality of exhaust holes (9) are opened at one end of the exhaust ring pipe (6) facing the tail of the submerged body (3). The inner cavity of the exhaust ring pipe (6) is divided into two independent exhaust chambers (10) in an upper and lower part. The two exhaust chambers (10) of the two exhaust ring pipes (6) are respectively connected to the air compressor (1).

2. The jet drag reduction device for a small waterplane area catamaran according to claim 1, characterized in that: The submerged body (3) is provided with a diverter box (5) connected to the air compressor (1) for diverting compressed gas, and the diverter box (5) is provided with a plurality of diverter holes (8) capable of achieving different exhaust flow rates, and the two exhaust chambers (10) of the two exhaust ring pipes (6) are respectively connected to different diverter holes (8).

3. The jet drag reduction device for a small waterplane area catamaran according to claim 2, characterized in that: The diverter box (5) comprises three independently arranged upper chambers for diverting gas, a middle chamber for storing the diverted gas, and a lower chamber for regulating the flow rate of the gas when it is discharged from the diverter hole (8).

4. The jet drag reduction device for a small waterplane area catamaran according to claim 3, characterized in that: A plurality of diversion boxes (11) are fixedly installed inside the upper chamber and are distributed in a circular array with the center point of the upper chamber, and a plurality of diversion boxes (11) are provided with vent holes (12) for gas to enter the diversion boxes (11) in the direction of the vertical center axis of the diversion box (5); a sealing plate (13) is fixedly installed on the inner wall of the middle chamber to divide its inner cavity into a plurality of independent gas storage chambers (14), the number and position of the gas storage chambers (14) are adapted to the diversion boxes (11), and the gas storage chambers (14) are arranged in a circular array. An air vent is provided between the air chamber (14) and the corresponding diverter box body (11) to connect the two. The diverter holes (8) are provided at the bottom of the diverter box (5), and the number and position of the diverter holes (8) are adapted to the diverter box body (11). A diverter air pipe (15) connected to the air storage chamber (14) and the corresponding diverter holes (8) is installed in the lower chamber, and an electric ball valve (16) for controlling the gas flow and a flow monitor (17) for monitoring the gas flow are installed on the diverter air pipe (15).

5. The jet drag reduction device for a small waterplane area catamaran according to claim 4, characterized in that: A rectifying orifice plate (18) for diverting is installed in the diverter box body (11); the edges of two adjacent diverter boxes (11) are affixed and fixedly connected, and the top and bottom plates of the diverter box bodies (11) are affixed and fixedly connected to the inner wall of the upper chamber.

6. The jet drag reduction device for a small waterplane area catamaran according to claim 2, characterized in that: A bracket (19) is fixedly connected to the outer periphery of the diversion box (5), and one end of the bracket (19) away from the diversion box (5) is fixedly connected to the inner wall of the submerged body (3).

7. The jet drag reduction device for a small waterplane area catamaran according to claim 1, characterized in that: The outer surface of the exhaust ring pipe (6) is configured as a conical surface, and the diameter of the exhaust pipe gradually increases from the head of the submerged body (3) to the tail of the submerged body (3); the exhaust hole (9) is configured as a conical shape, and the diameter of the exhaust hole (9) gradually increases from the head of the submerged body (3) to the tail of the submerged body (3), and a certain distance exists between the exhaust hole (9) and the submerged body (3).

8. The jet drag reduction device for a small waterplane area catamaran according to claim 1, characterized in that: A plurality of density sensors (7) are provided, and the density sensors (7) are symmetrically mounted on the upper surface and the lower surface of the submerged body (3), and the density sensors (7) are located on the side of the exhaust ring pipe (6) facing the tail of the submerged body (3).

9. The control method of the jet drag reduction device for a small waterplane area catamaran according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1: Start the air compressor (1), and the compressed gas is diverted by the diverter box (5) and enters the two independent exhaust chambers (10) of the two exhaust ring pipes (6) respectively. The gas discharged through the exhaust chamber (10) above the exhaust ring pipe (6) near the head of the submersible (3) forms a first gas barrier layer on the upper surface of the middle part of the submersible (3), the gas discharged through the exhaust chamber (10) above the exhaust ring pipe (6) near the head of the submersible (3) forms a second gas barrier layer on the lower surface of the middle part of the submersible (3), the gas discharged through the exhaust chamber (10) above the exhaust ring pipe (6) near the tail of the submersible (3) forms a third gas barrier layer on the upper surface of the tail of the submersible (3), and the gas discharged through the exhaust chamber (10) above the exhaust ring pipe (6) near the tail of the submersible (3) forms a fourth gas barrier layer on the lower surface of the tail of the submersible (3); S2: Gas density sensors (7) symmetrically arranged on one side of the two exhaust ring pipes (6) detect the fluid density at the first gas barrier layer, the second gas barrier layer, the third gas barrier layer and the fourth gas barrier layer respectively; S3: respectively judging whether the fluid density at the first gas barrier layer, the second gas barrier layer, the third gas barrier layer and the fourth gas barrier layer reaches a preset value; if the fluid density at a certain gas barrier layer reaches the preset value, the current state of the gas barrier layer is maintained; if the fluid density at a certain gas barrier layer is lower than the preset value, adjusting the gas flow rate discharged from the exhaust chamber (10) corresponding to the gas barrier layer until the fluid density at the gas barrier layer of the gas barrier layer reaches the preset value.

10. The control method of the small waterplane area catamaran jet drag reduction device according to claim 9, characterized in that: The method for adjusting the gas flow rate discharged from the exhaust chamber (10) is as follows: an electric ball valve (16) on a diversion air pipe (15) corresponding to an air compressor (1) connected to the exhaust chamber (10) or a diversion hole (8) connected to the exhaust chamber (10) is adjusted to control the gas flow rate discharged from the exhaust chamber (10), and a flow monitor (17) monitors the gas flow rate discharged from the corresponding diversion air pipe (15) in real time.

Images