Object surface microstructure and bubble composite resistance reduction measurement experiment device based on Taylor-Couette flow

Abstract

The invention provides an object surface microstructure and bubble composite resistance reduction measurement experimental device based on Taylor-Couette flow, and relates to the technical field of Taylor-Couette flow resistance reduction measurement. Comprising a rack supporting column, a rack supporting plate, a motor, an upper coupler, a torque sensor, an inner driving shaft, a lower coupler, a mechanical seal, an upper end sealing connecting piece, an inner rotor, an outer rotor, a lower end sealing connecting piece, a supporting column, a rack base, a one-way vent valve and a chassis. According to the invention, convenient replacement of different inner rotors with surface microstructures, smooth surfaces and the like can be realized according to experimental requirements; the switching between two ventilation modes of outward ventilation inside the inner rotor and vertical upward ventilation at the bottom of the inner rotor can be realized; flow control under different rotating speeds and gas flows can be realized through the gas flow meter and the motor controller; resistance borne by the inner rotor under different flow working conditions can be measured in real time through the torque sensor, and therefore research on the surface microstructure and bubble composite resistance reduction characteristic under Taylor-Couette flow is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of drag reduction measurement of Taylor-Couette flow, and particularly relates to an experimental device for measuring the combined drag reduction of microstructures and bubbles on the surface of an object based on Taylor-Couette flow. Background Art

[0002] During the navigation of surface ships and underwater vehicles, the propulsion energy consumption mainly comes from the work done by fluid resistance. To reduce fuel consumption, reduce pollution emissions, and increase the speed and range, drag reduction technology has been widely applied in the design of ships and underwater vehicles. Currently, underwater drag reduction technologies mainly include: drag reduction by microstructures on the surface of an object (such as grooved or corrugated surfaces), drag reduction by bubbles (forming a gas film by injecting bubbles), drag reduction by hydrophobic / superhydrophobic surfaces (using surface hydrophobicity to reduce drag), etc.

[0003] Previous studies on drag mainly focused on channel flow, flat plate flow, cavity flow, etc. Since their flows may exhibit spatial or temporal dependence, it is difficult to generalize the drag reduction data of different experimental devices into a unified conclusion, which brings difficulties to the general explanation of the drag reduction mechanism. The Taylor-Couette (TC) flow system overcomes these problems because in TC flow, a statistical steady state is easily achieved, and the system is a closed system with a clear energy balance, capable of measuring the global torque and gas volume fraction with high precision, directly correlating the influence of bubbles or microstructures on drag, and is very suitable for studying the drag experienced by an object when moving in bubble flow. Nevertheless, existing studies on drag reduction using TC flow devices often only consider one aspect, such as only studying drag reduction by bubbles or only considering the influence of microstructures on the surface of an object on drag reduction. These single studies often have certain limitations because in practical applications, the drag reduction effect often depends on the synergistic action of multiple factors (such as the coupling effect of superhydrophobic grooves and bubble injection). And the ventilation mode of existing TC flow devices is disconnected from the actual scenario. Existing TC flow devices mostly use bottom vertical ventilation, while ship drag reduction systems usually actively release bubbles through the hull sidewall or surface microstructures, resulting in significant differences between the experimental conditions and engineering applications. Therefore, an experimental device that can simulate complex actual environments and support multi-factor synergistic drag reduction research is needed to reveal the coupling mechanism between bubbles and microstructures and provide a theoretical basis for engineering applications.

[0004] To solve the above problems, the present invention provides an experimental device for measuring the combined drag reduction of surface microstructures and bubbles on an object based on Taylor-Couette flow, which can conveniently replace different inner rotor modules with surface microstructures and smooth surfaces according to experimental requirements. Moreover, various ventilation methods such as internal ventilation of the inner rotor or vertical ventilation at the bottom can be adopted, aiming to study the combined drag reduction mechanism of surface microstructures and bubbles on the inner rotor surface through a ventilation environment closer to actual applications, providing theoretical support and technical means for applications in related fields. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides an experimental device for measuring the combined drag reduction of surface microstructures and bubbles on an object based on Taylor-Couette flow, which has a simple structure, is driven by a single motor, has a low cost, and can achieve flow control under different rotational speeds and air flow rates.

[0006] To this end, the present invention provides an experimental device for measuring the combined drag reduction of surface microstructures and bubbles on an object surface based on Taylor-Couette flow, including a frame support column, a frame support plate, a motor, an upper coupling, a torque sensor, an inner drive shaft, a lower coupling, a mechanical seal, an upper end seal connecting member, an inner rotor, an outer rotor, a lower end seal connecting member, a support column, a frame base, a one-way ventilation valve, and a chassis. The frame support column is installed at one end above the frame base. One end of the frame support plate is installed on the frame support column, and the frame support plate is parallel and aligned with the frame base. The motor is installed at one end of the frame support plate above and away from the frame support column, and the output shaft of the motor penetrates to the lower side of the frame support plate. The inner drive shaft is connected to the output shaft of the motor through the upper coupling. The torque sensor is sleeved outside the inner drive shaft, and the torque sensor is slidably arranged with the inner drive shaft and is connected to the lower side of the frame support plate. The inner rotor is coaxially installed at the lower end of the inner drive shaft through the lower coupling. The chassis is arranged above the frame base through the support column. The outer rotor is fixed above the chassis, and a lower end seal connecting member is arranged at the lower end of the outer rotor, and an upper end seal connecting member is arranged at the upper end of the outer rotor. The outer rotor is coaxially sleeved outside the inner rotor. A circumferential gap is left between the inner rotor and the outer rotor. The chassis is provided with a plurality of one-way ventilation valves around the central axis. The one-way ventilation valves are located in the circumferential gap. A mechanical seal is arranged at the connection between the upper end seal connecting member and the inner drive shaft. By setting the motor, the inner rotor, the outer rotor, and the one-way ventilation valve, a viscous fluid is arranged between the inner rotor and the outer rotor, and bubbles are conveyed to the viscous fluid through the one-way ventilation valve. The motor drives the inner rotor to rotate, and the inner rotor is replaced among different inner rotors with surface microstructures and smooth surfaces according to experimental requirements, which is convenient for conducting research in the field of drag reduction measurement technology of Taylor-Couette flow by bubbles. The structure is simple, one motor can meet the research requirements, the cost is low, the rotation speed of the motor is controlled by a controller, and the flow rate of the bubbles is controlled by a bubble generator, and the control of different rotation speeds and gas flow rates can be achieved.

[0007] Further, a sliding bearing is sleeved between the inner drive shaft and the upper end seal connecting member. The upper end seal connecting member and the outer rotor adopt a static seal. The upper end of the one-way ventilation valve and the lower end seal connecting member adopt a static seal, and the one-way ventilation valves are arranged at equal intervals. The lower end of the one-way ventilation valve is connected to a bubble generator through a pipeline. The one-way ventilation valve is used to prevent the viscous fluid from flowing out of the outer rotor through the one-way ventilation valve. The output shaft of the motor, the upper coupling, the inner drive shaft, the lower coupling, the inner rotor, and the outer rotor are all coaxially and vertically arranged on the frame base.

[0008] Further, the motor is connected to an external power supply and a controller through wires and is used to control the rotation speed of the motor; the torque sensor is connected to the external power supply and the controller through wires and is used to monitor the torque of the inner rotor; a plurality of struts are provided, and the struts are arranged around the central axis of the chassis. The struts are used to adjust and support the chassis, and the struts are arranged at equal intervals. By setting the torque sensor, the torque sensor is used to monitor the torque of the inner drive shaft. The inner drive shaft rotates synchronously with the inner rotor, which is convenient for studying the change of the torque of the inner rotor due to the addition of bubbles, and is of great significance for understanding and optimizing the hydrodynamic system involving bubbles. By setting the struts, the struts are located below the chassis, and the chassis is adjusted by the struts to ensure that the motor output shaft, the upper coupling, the inner drive shaft, the lower coupling, the inner rotor and the outer rotor are all coaxially and vertically arranged, improving the working efficiency of the measuring device.

[0009] Further, the inner rotor adopts a detachable structure, which is convenient for the inner rotor to be quickly replaced with different inner rotor modules such as surface microstructures and surface smoothness according to experimental requirements. The inner rotor adopts the switching of two ventilation modes, namely internal outward ventilation and bottom vertical upward ventilation, aiming to be closer to the ventilation environment of actual applications.

[0010] Compared with the prior art, the present invention has the following beneficial effects:

[0011] 1. In the present invention, by setting a motor, an inner rotor, an outer rotor and a one-way ventilation valve, a viscous fluid is provided between the inner rotor and the outer rotor, and bubbles are conveyed to the viscous fluid through the one-way ventilation valve. The motor drives the inner rotor to rotate, and the inner rotor is replaced between different inner rotors with surface microstructures and surface smoothness according to experimental requirements, which is convenient for studying the influence of bubbles on the drag reduction measurement of Taylor-Couette flow. The structure is simple, and one motor can meet the research needs, with low cost. The rotation speed of the motor is controlled by the controller, and the flow rate of the bubbles is controlled by the bubble generator, and the control of different rotation speeds and gas flow rates can be realized;

[0012] 2. In the present invention, by setting a torque sensor, the torque sensor is used to monitor the torque of the inner drive shaft. The inner drive shaft rotates synchronously with the inner rotor, which is convenient for studying the change of the torque of the inner rotor due to the surface microstructure of the inner rotor and the addition of bubbles, so as to realize the research on the composite drag reduction mechanism of the surface microstructure and bubbles of the inner rotor.

[0013] 3. In the present invention, by setting struts, the struts are located below the chassis, and the chassis is adjusted by the struts to ensure that the motor output shaft, the upper coupling, the inner drive shaft, the lower coupling, the inner rotor and the outer rotor are all coaxially and vertically arranged, improving the working efficiency of the measuring device;

[0014] 4. In the present invention, it is possible to switch between two ventilation modes: ventilation from the inside to the outside of the inner rotor and vertical upward ventilation from the bottom, so as to better approximate the ventilation environment of actual applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic structural view of the present invention;

[0016] Figure 2 is a schematic structural view of the inner rotor with surface microstructures of the present invention;

[0017] Figure 3 is a schematic view of the inner rotor structure adopting the inner rotor internal ventilation mode of the present invention;

[0018] Figure 4 is of the present invention Figure 3 cross-sectional view taken along A-A;

[0019] Figure 5 is of the present invention Figure 3 cross-sectional view taken along B-B;

[0020] Figure 6 is a schematic structural view of the frame support column, inner rotor, outer rotor, frame base and one-way ventilation valve of the present invention;

[0021] Figure 7 is a schematic structural view of the one-way ventilation valve of the present invention.

[0022] In the figures:

[0023] 1. Frame support column; 2. Frame support plate; 3. Motor; 4. Upper coupling; 5. Torque sensor; 6. Inner drive shaft; 7. Lower coupling; 8. Mechanical seal; 9. Upper end seal connecting piece; 10. Inner rotor; 11. Outer rotor; 12. Lower end seal connecting piece; 13. Support pillar; 14. Frame base; 15. One-way ventilation valve; 16. Chassis. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The present invention will be further described below with reference to the accompanying drawings:

[0025] Embodiment:

[0026] As shown in Figure 1 to Figure 7 shown

[0027] The present invention provides an experimental device for measuring the combined drag reduction of object surface microstructures and bubbles based on Taylor-Couette flow, including a frame support column 1, a frame support plate 2, a motor 3, an upper coupling 4, a torque sensor 5, an inner drive shaft 6, a lower coupling 7, a mechanical seal 8, an upper end seal connecting member 9, an inner rotor 10, an outer rotor 11, a lower end seal connecting member 12, a support column 13, a frame base 14, a one-way air vent valve 15 and a chassis 16. One end of the frame support column 1 is installed above the frame base 14; one end of the frame support plate 2 is installed on the frame support column 1, and the frame support plate 2 is parallel and aligned with the frame base 14; the motor 3 is installed at one end of the frame support plate 2 above and away from the frame support column 1, and the output shaft of the motor 3 penetrates to the lower side of the frame support plate 2; the inner drive shaft 6 is connected to the output shaft of the motor 3 through the upper coupling 4; the torque sensor 5 is sleeved outside the inner drive shaft 6, and the torque sensor 5 is slidably arranged with the inner drive shaft 6, and the torque sensor 5 is connected to the lower side of the frame support plate 2; the inner rotor 10 is coaxially installed at the lower end of the inner drive shaft 6 through the lower coupling 7; the chassis 16 is arranged above the frame base 14 through the support column 13; the outer rotor 11 is fixed above the chassis 16, and a lower end seal connecting member 12 is arranged at the lower end of the outer rotor 11, and an upper end seal connecting member 9 is arranged at the upper end of the outer rotor 11, wherein the outer rotor 11 is coaxially sleeved outside the inner rotor 10; a circumferential gap is left between the inner rotor 10 and the outer rotor 11; a plurality of one-way air vent valves 15 are arranged around the central axis of the chassis 16; the one-way air vent valves 15 are located in the circumferential gap; a mechanical seal 8 is arranged at the connection between the upper end seal connecting member 9 and the inner drive shaft 6; by arranging the motor 3, the inner rotor 10, the outer rotor 11 and the one-way air vent valves 15, a viscous fluid is arranged between the inner rotor 10 and the outer rotor 11, and bubbles are conveyed to the viscous fluid through the one-way air vent valves 15, and the motor 3 drives the inner rotor 10 to rotate, which is convenient for studying the influence of bubbles on the drag reduction measurement of Taylor-Couette flow. The structure is simple, one motor 3 can meet the research requirements, the cost is low, the rotation speed of the motor 3 is controlled by a controller, and the flow rate of the bubbles is controlled by a bubble generator, and the control of different rotation speeds and air flow rates can be realized.

[0028] In this embodiment, specifically, a sliding bearing is sleeved between the inner drive shaft 6 and the upper end seal connecting member 9; a static seal is adopted between the upper end seal connecting member 9 and the outer rotor 11; a static seal is adopted between the upper end of the one-way air vent valve 15 and the lower end seal connecting member 12, and the one-way air vent valves 15 are arranged at equal intervals. The lower end of the one-way air vent valve 15 is connected to a bubble generator through a pipeline, wherein the one-way air vent valve 15 is used to prevent the viscous fluid from flowing out of the outer rotor 11 through the one-way air vent valve 15; the output shaft of the motor 3, the upper coupling 4, the inner drive shaft 6, the lower coupling 7, the inner rotor 10 and the outer rotor 11 are all coaxially and vertically arranged on the frame base 14.

[0029] In this embodiment, the motor 3 is connected to an external power supply and a controller through wires and is used to control the rotation speed of the motor 3; the torque sensor 5 is connected to an external power supply and a controller through wires and is used to monitor the torque of the inner rotor 10; a plurality of struts 13 are used, and the struts 13 are arranged around the central axis of the chassis 16. The struts 13 are used to adjust and support the chassis 16, and the struts 13 are arranged at equal intervals; the inner rotor 10 adopts a detachable structure, which facilitates the convenient replacement of different inner rotor modules such as surface microstructure and surface smoothness of the inner rotor 10 according to experimental requirements. The inner rotor 10 adopts the switching between two ventilation modes of internal outward ventilation and bottom vertical upward ventilation, and can be replaced between different inner rotors with surface microstructure and surface smoothness according to experimental requirements, so as to realize the research on the composite drag reduction mechanism of the surface microstructure and bubbles of the inner rotor; by setting the torque sensor 5, the torque sensor 5 is used to monitor the torque of the inner drive shaft 6. The inner drive shaft 6 rotates synchronously with the inner rotor 10, which is convenient for studying the change of the torque of the inner rotor 10 due to the addition of the surface microstructure and bubbles of the inner rotor, and is of great significance for understanding and optimizing the hydrodynamic system involving bubbles; by setting the struts 13, the struts 13 are located below the chassis 16, and the chassis 16 is adjusted through the struts 13 to ensure that the output shaft of the motor 3, the upper coupling 4, the inner drive shaft 6, the lower coupling 7, the inner rotor 10 and the outer rotor 11 are all coaxially and vertically arranged, improving the working efficiency of the measuring device.

[0030] Working principle

[0031] In the present invention, during use, a viscous fluid is arranged between the inner rotor 10 and the outer rotor 11, and bubbles are conveyed into the viscous fluid through the one-way ventilation valve 15. The motor 3 drives the inner rotor 10 to rotate. The inner rotor is replaced between different inner rotors with surface microstructure and surface smoothness according to experimental requirements, which is convenient for studying the influence of bubbles on the drag reduction measurement of Taylor-Couette flow. The structure is simple. Using one motor 3 can meet the research requirements, and the cost is low. The rotation speed of the motor 3 is controlled by the controller, and the flow rate of the bubbles is controlled by the bubble generator, and the control of different rotation speeds and gas flow rates can be realized; the torque sensor 5 is used to monitor the torque of the inner drive shaft 6. The inner drive shaft 6 rotates synchronously with the inner rotor 10, which is convenient for studying the change of the torque of the inner rotor 10 due to the addition of bubbles, and is of great significance for understanding and optimizing the hydrodynamic system involving bubbles; the struts 13 are located below the chassis 16, and the chassis 16 is adjusted through the struts 13 to ensure that the output shaft of the motor 3, the upper coupling 4, the inner drive shaft 6, the lower coupling 7, the inner rotor 10 and the outer rotor 11 are all coaxially and vertically arranged, improving the working efficiency of the measuring device; the convenient replacement of different inner rotors 10 with surface microstructure and surface smoothness and the switching between two ventilation modes of internal outward ventilation and bottom vertical upward ventilation of the inner rotor 10 can be realized, so as to realize the research on the composite drag reduction mechanism of the surface microstructure and bubbles of the inner rotor 10.

[0032] Any technical solution that makes use of the technical solution described in the present invention, or is designed by a person skilled in the art inspired by the technical solution of the present invention and achieves the above technical effects, shall fall within the protection scope of the present invention.

Claims

1. An experimental device for measuring the composite drag reduction of surface microstructure and bubbles based on Taylor-Couette flow, characterized by: The invention comprises a frame support column (1), a frame support plate (2), a motor (3), an upper coupling (4), a torque sensor (5), an inner drive shaft (6), a lower coupling (7), a mechanical seal (8), an upper end sealing connector (9), an inner rotor (10), an outer rotor (11), a lower end sealing connector (12), a support column (13), a frame base (14), a one-way vent valve (15) and a chassis (16), wherein the frame support column (1) is mounted on the frame base (14). one end of the frame support plate (2) is mounted on the frame support column (1), and the frame support plate (2) is aligned parallel to the frame base (14); the motor (3) is mounted on the end of the frame support plate (2) that is away from the frame support column (1), and the output shaft of the motor (3) passes through the lower side of the frame support plate (2); the inner drive shaft (6) is connected to the output shaft of the motor (3) through an upper coupling (4); the torque sensor (5) is sleeved on the inner drive shaft The outer side of the inner drive shaft (6) is provided with a torque sensor (5) which is slidably arranged with the inner drive shaft (6), and the torque sensor (5) is connected with the lower side of the frame support plate (2); the inner rotor (10) is coaxially mounted on the lower end of the inner drive shaft (6) through a lower coupling (7); the chassis (16) is arranged above the frame base (14) through a support (13); the outer rotor (11) is fixed above the chassis (16), and the lower end of the outer rotor (11) is provided with a lower end seal A connecting piece (12), wherein an upper end sealing connecting piece (9) is provided at the upper end of the outer rotor (11), wherein the outer rotor (11) is coaxially sleeved on the outside of the inner rotor (10); an annular gap is left between the inner rotor (10) and the outer rotor (11); the chassis (16) is provided with a plurality of one-way vent valves (15) around the central axis; the one-way vent valves (15) are located in the annular gap; and a mechanical seal (8) is provided at the connection between the upper end sealing connecting piece (9) and the inner drive shaft (6).

2. The Taylor-Couette flow-based object surface microstructure and bubble composite drag reduction measurement experimental device as claimed in claim 1, characterized in that: A sliding bearing is sleeved between the inner drive shaft (6) and the upper end sealing connector (9); and a static seal is adopted between the upper end sealing connector (9) and the outer rotor (11).

3. The experimental device for measuring the composite drag reduction of surface microstructure and bubbles based on Taylor-Couette flow according to claim 1, characterized in that: A static seal is adopted between the upper end of the one-way vent valve (15) and the lower end sealing connector (12), and the one-way vent valves (15) are arranged at equal intervals. The lower end of the one-way vent valve (15) is connected to the bubble generator through a pipeline, wherein the one-way vent valve (15) is used to prevent the viscous fluid from flowing out of the outer rotor (11) through the one-way vent valve (15).

4. The Taylor-Couette flow-based object surface microstructure and bubble composite drag reduction measurement experimental device as claimed in claim 1, characterized in that: The output shaft of the motor (3), the upper coupling (4), the inner drive shaft (6), the lower coupling (7), the inner rotor (10) and the outer rotor (11) are all coaxially and vertically arranged on a frame base (14).

5. The Taylor-Couette flow-based object surface microstructure and bubble composite drag reduction measurement experimental device as claimed in claim 1, characterized in that: The motor (3) is connected to an external power source and a controller via a wire, and is used to control the rotation speed of the motor (3).

6. The Taylor-Couette flow-based object surface microstructure and bubble composite drag reduction measurement experimental device as claimed in claim 1, characterized in that: The torque sensor (5) is connected to an external power source and a controller via a wire and is used to monitor the torque of the inner rotor (10).

7. The experimental device for measuring the composite drag reduction of surface microstructure and bubbles based on Taylor-Couette flow according to claim 1, characterized in that: The pillars (13) are multiple and are arranged around the central axis of the chassis (16). The pillars (13) are used to adjust and support the chassis (16), wherein the pillars (13) are arranged at equal intervals.

8. The Taylor-Couette flow-based object surface microstructure and bubble composite drag reduction measurement experimental device as claimed in claim 1, characterized in that: The inner rotor (10) adopts a detachable structure, which facilitates the convenient replacement of different inner rotor modules such as surface microstructure and surface smoothness according to experimental requirements. The inner rotor (10) adopts the switching of two ventilation modes: internal outward ventilation and bottom upright upward ventilation.

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