CN111721496A - Resistance testing device and method under high Reynolds number in fluid - Google Patents
Resistance testing device and method under high Reynolds number in fluid Download PDFInfo
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- CN111721496A CN111721496A CN201910202409.4A CN201910202409A CN111721496A CN 111721496 A CN111721496 A CN 111721496A CN 201910202409 A CN201910202409 A CN 201910202409A CN 111721496 A CN111721496 A CN 111721496A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M10/00—Hydrodynamic testing; Arrangements in or on ship-testing tanks or water tunnels
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Abstract
The invention discloses a resistance testing device and method under a large Reynolds number in fluid. The device comprises: the driving mechanism is in transmission connection with the test sample through a transmission shaft and at least used for providing rotary power for the test sample; the rotating speed adjusting mechanism is connected with the driving mechanism and at least used for adjusting the rotating speed of the driving mechanism and keeping the rotating speed of the driving mechanism constant; a resistive environment mechanism comprising a housing containing a fluid medium and at least for providing a resistive environment for a test sample immersed in the fluid medium; a resistance monitoring mechanism for at least monitoring a flow transition of a fluid medium surrounding the test sample during the testing. The testing device provided by the invention can accurately test the resistance and drag reduction of the disc at high Reynolds number, and is convenient for researchers to research and analyze the resistance and drag reduction mechanism.
Description
Technical Field
The invention relates to a resistance testing device under a large Reynolds number in fluid, in particular to a testing device for testing the frictional resistance of different test disks in water and the flow state of water near the test disks at a high rotating speed, namely a high Reynolds number.
Background
Along with the continuous deepening of the degree of automation, the dependence of human beings on non-renewable energy sources is stronger and stronger, how to reduce the consumption of the energy sources becomes the important part of the research at present, a great problem is faced in the daily life and the national defense of the human beings, namely, the frictional resistance under high Reynolds number, particularly the national defense, if the frictional resistance of a ship is reduced by 10%, the speed and the range of the ship are greatly improved, and therefore, the design of the frictional resistance device for evaluating the sample has important strategic and practical significance for improving the energy utilization, the speed and the range of the water and underwater aircrafts.
At present, devices for testing the frictional resistance of the surface of a sample mainly comprise experimental devices such as a towing tank, a large-scale wind tunnel, a water tank and the like, and the devices make great contribution to the research on the frictional resistance and the flow field state of the sample. However, the above devices have significant problems, such as: (1) the cost of the above devices is very expensive and not affordable for any enterprises or research units, thus making researchers prohibitive and hindering the development of frictional resistance research. (2) The structure is complicated and the maintenance is difficult. (3) The occupied area is large, and the requirements on the knowledge and the skill of operators are high. Therefore, how to design a resistance testing device with low cost, simple operation and reliable test becomes the focus of research.
Disclosure of Invention
The invention mainly aims to provide a device and a method for testing resistance under a large Reynolds number in fluid, the device has the advantages of simple structure, low preparation cost, no need of sealing, strong operability, high precision, higher reliability and stability, and can be used for long-distance petroleum transportation, analysis and evaluation of resistance of airplanes and underwater vehicles, and research on frictional resistance and resistance reduction mechanisms.
In order to achieve the purpose, the technical scheme adopted by the invention comprises the following steps:
the embodiment of the invention provides a resistance testing device under a large Reynolds number in fluid, which comprises:
the driving mechanism is in transmission connection with the test sample through a transmission shaft and at least used for providing rotary power for the test sample;
the rotating speed adjusting mechanism is connected with the driving mechanism and at least used for adjusting the rotating speed of the driving mechanism and keeping the rotating speed of the driving mechanism constant;
a resistive environment mechanism comprising a housing containing a fluid medium and at least for providing a resistive environment for a test sample immersed in the fluid medium;
a resistance monitoring mechanism for at least monitoring a flow transition of a fluid medium surrounding the test sample during the testing.
Furthermore, the rotating speed adjusting mechanism comprises a rotating speed monitoring mechanism and a rotating speed adjusting mechanism, and the rotating speed monitoring mechanism is connected with the driving mechanism and the transmission shaft respectively.
Furthermore, the rotating speed monitoring mechanism is connected with the driving mechanism through a first coupler, and the rotating speed monitoring mechanism is connected with the transmission shaft through a second coupler.
Further, the output shafts of the rotating speed monitoring mechanism, the transmission shaft and the driving mechanism are coaxially arranged, wherein the rotating speed monitoring mechanism comprises a torque sensor and a torque sensor display instrument, and the rotating speed adjusting mechanism comprises a speed regulator.
Further, the test sample is detachably arranged at one end of the transmission shaft.
Furthermore, the test sample is in threaded connection with the transmission shaft, a locking nut is further arranged at one end of the transmission shaft, and the thread directions of the test sample and the locking nut are opposite.
Further, the test sample comprises a low density, high hardness test disc.
Preferably, the material of the test disc includes an aluminum alloy, but is not limited thereto.
Further, the thickness of the test disc is more than 5mm, and the radius is more than 20 cm.
Furthermore, the resistance monitoring mechanism comprises a laser sheet light source and a particle image velocimeter, wherein light beams emitted by the laser sheet light source are perpendicular to the designated surface of the test sample, and the orientation of a camera of the particle image velocimeter is perpendicular to the light beams emitted by the laser sheet light source and parallel to the designated surface of the test sample.
Further, the resistance testing device under the large reynolds number in the fluid further comprises: the supporting platform is fixed on a base body (such as the ground) through a supporting column, and the driving mechanism and the rotating speed adjusting mechanism are fixed on the supporting platform.
Furthermore, the driving mechanism comprises a driving motor, and a positioning screw capable of adjusting the perpendicularity of an output shaft of the driving motor is further arranged between the driving motor and the supporting platform.
Preferably, the driving motor comprises a direct current motor, the power of the direct current motor is more than 3KW, and the rotating speed is continuously adjustable within 0-5000 rpm.
Furthermore, the transmission shaft is also connected with a verticality adjusting mechanism, and the verticality adjusting mechanism is fixed on the supporting platform and at least used for adjusting the verticality of the transmission shaft.
Preferably, the verticality adjusting mechanism comprises a horizontal fixed seat.
Further, the fluid medium comprises water, and the box body is a transparent box body.
Preferably, the box body is a tempered glass box body, but is not limited thereto.
Further, the resistance testing device under the large reynolds number in the fluid further comprises: and the control assembly is connected with the driving mechanism, the rotating speed adjusting mechanism and the resistance monitoring mechanism.
The embodiment of the invention also provides a resistance testing method under the condition of large Reynolds number in fluid, which comprises the following steps:
providing a resistance testing device under a large Reynolds number in the fluid;
fixing a test sample on a transmission shaft, placing the test sample in a box body, and enabling the test sample to enter a fluid medium in the box body;
the test sample is rotated at different rotating speeds by adjusting the rotating speed adjusting mechanism, so that the resistance of the test sample at different rotating speeds in the fluid medium is tested;
and observing the flowing state of the fluid medium around the test sample at least through the resistance monitoring mechanism, thereby obtaining the frictional resistance mechanism of the test sample.
Compared with the prior art, the testing device provided by the invention has the advantages of simple structure, low preparation cost, no need of sealing, strong operability, high precision, higher reliability and stability, capability of accurately testing the resistance and resistance reduction of the disc at high Reynolds number, and convenience for researchers to research and analyze the resistance and resistance reduction mechanism.
Drawings
FIG. 1 is a schematic diagram of a resistance testing apparatus for high Reynolds number in a fluid according to an exemplary embodiment of the present invention;
FIG. 2 is a schematic diagram of a resistance testing apparatus for high Reynolds number in a fluid according to an exemplary embodiment of the present invention;
FIG. 3 is a flow chart of a method for resistance testing at high Reynolds numbers in a fluid according to an exemplary embodiment of the present invention;
description of reference numerals: the test method comprises the following steps of 1-direct current motor, 2-supporting platform, 3-coupler, 4-torque sensor, 5-horizontal fixed seat, 6-transmission shaft, 7-test disc, 8-self-locking nut, 9-water tank, 10-ground foot, 11-torque sensor display instrument, 12-direct current motor speed regulator, 13-fixing screw, 14-positioning screw and 15-positioning plate.
Detailed Description
In view of the deficiencies in the prior art, the inventors of the present invention have made extensive studies and extensive practices to provide technical solutions of the present invention. The technical solution, its implementation and principles, etc. will be further explained as follows.
The embodiment of the invention provides a resistance testing device under a large Reynolds number in fluid, which is characterized by comprising a direct current motor, a support platform, a positioning screw, a shaft coupling, a direct current motor, a positioning plate, a torque sensor, a horizontal fixing seat, a self-locking screw, a support platform, a horizontal fixing seat, a positioning plate, a shaft coupling, a transmission shaft, a positioning shaft; the perpendicularity of the direct current motor can be adjusted through the positioning screw, so that the direct current motor and the torque sensor are in the same straight line, the output power of the motor is reduced, and the service life of the coupler is prolonged; the torque sensor and the transmission shaft can be positioned on the same straight line by adjusting the position of the positioning plate, so that the test reliability of the torque sensor is improved, the vertical sliding of the transmission shaft can be positioned by the horizontal fixing seat, the lower pulling force of the torque sensor is reduced, and the service life of the torque sensor is prolonged; the screw thread and the rotation of the self-locking nut can be reversed, so that the disc is prevented from slipping and loosening during testing.
Furthermore, the light beam of the laser sheet light source is vertical to the surface of the test disc, and the light beam of the laser sheet light source is vertical to the surface of the test disc and parallel to the surface of the test disc by the particle image velocimeter.
Furthermore, in order to prevent the test disc from being distorted and deformed in the test, the test disc is made of light high-strength aluminum alloy, the thickness of the aluminum alloy is more than 5mm, and the radius of the aluminum alloy is more than 20 cm; the water tank adopts transparent organic glass so as to facilitate the light beam of the laser sheet light source to pass and the capture of the water flowing state by a camera of the particle image velocimeter; the power of the driving motor is more than 3KW, the maximum rotating speed is 5000rpm, the rotating speed of the motor can be directly input through a control system, the rotating speed of the direct current motor is adjusted through the testing rotating speed of the torque sensor, the direct current motor is in a constant rotating speed state, and the testing stability and reliability are improved.
The technical solution, the implementation process and the principle thereof will be further explained with reference to the drawings.
Referring to fig. 1 and 2, a resistance testing device under a large reynolds number in a fluid, namely a testing device for measuring frictional resistance of a test disc and flow state of a flow field on the wall surface of the test disc at different rotating speeds, comprises a direct current motor 1, a supporting platform 2, a coupler 3, a torque sensor 4, a horizontal fixing seat 5, a transmission shaft 6, a test disc 7, a self-locking nut 8, a water tank 9, a ground landing foot 10, a torque sensor display instrument 11, a direct current motor speed regulator 12, a fixing screw 13, a positioning screw 14 and a positioning plate 15; the support platform 2 is arranged on a plane floor through a ground foot 10, the direct current motor 1 is arranged on the support platform 2 through a fixing screw 13, the verticality of an output shaft of the direct current motor can be adjusted through a positioning screw 14, and the rotating speed of the direct current motor 1 is ensured to be continuously adjustable within 0-5000 rpm; the torque sensor 4 is connected with the direct current motor 1 through the coupler 3, the torque sensor 4 is fixed on the supporting platform through the positioning plate 15, and the axis of the torque sensor 4, the axis of the direct current motor 1 and the axis of the transmission shaft are on the same straight line; the transmission shaft 6 and the torque sensor 4 are connected together through a coupler 3, the transmission shaft 6 is fixed on the supporting platform through a horizontal fixing seat 5, and the positioning and fixing of the transmission shaft 6 can be adjusted through the horizontal fixing seat 5; the test disc 7 is fixed at the lower end of the transmission shaft 6 through a self-locking nut (i.e. the aforementioned locking nut) 8 (the test disc 7 itself can be screwed on the transmission shaft), wherein the direction of rotation of the dc motor 1 is opposite to the screwing direction of the self-locking nut 8, and the screwing direction of the test disc 7 is opposite to that of the self-locking nut 8. The test disc 7 is placed in the water tank 9, the water tank 9 is made of transparent toughened glass, light beams of the laser sheet light source are perpendicular to the disc surface of the test disc 7, and the particle image velocimeter is perpendicular to the light beams of the laser sheet light source and parallel to the disc surface of the test disc 7.
Specifically, the speed regulator 12 of the direct current motor can be adjusted to adjust the rotating speed of the direct current motor 1, and the rotating speed feedback is tested by the torque sensor 4 to stabilize the rotating speed of the direct current motor 1 at a constant value; the laser sheet light source and the particle image velocimeter can monitor and analyze the flow field of the test disc 7 at different rotating speeds and analyze the mechanism of the surface friction resistance of the test disc.
Referring to fig. 3, a method for testing resistance in a fluid at a large reynolds number includes:
providing a resistance testing device under a large Reynolds number in the fluid;
fixing the test disc on the transmission shaft, placing the test disc in a water tank, and enabling a test sample to enter water in the water tank;
the test sample is rotated at a set rotating speed by adjusting the rotating speed adjusting mechanism, and the resistance of the test disc in water is further tested at the rotating speed;
and observing the flowing state of water around the test disc at least through the resistance monitoring mechanism, thereby obtaining the frictional resistance mechanism of the test sample.
After the test is finished, the motor stops rotating, the self-locking screw cap 8 is loosened to switch the test disc 7, and the next experiment is carried out.
It should be noted that the control assembly, the torque sensor display instrument, the direct current motor speed regulator, the particle image velocimeter, the laser sheet light source and the like adopted by the resistance testing device under the large reynolds number in the fluid provided by the invention can be all commercially available equipment, and can also be commercially available, wherein the adopted numerical control program and the like can also be commercially available.
The testing device provided by the invention has the advantages of simple structure, low preparation cost, no need of sealing, strong operability, high precision, higher reliability and stability, capability of accurately testing the resistance and resistance reduction of the disc at high Reynolds number, and convenience for researchers to research and analyze the resistance and resistance reduction mechanism.
It should be understood that the above-mentioned embodiments are merely illustrative of the technical concepts and features of the present invention, which are intended to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and therefore, the protection scope of the present invention is not limited thereby. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.
Claims (10)
1. A resistance testing device under large Reynolds number in fluid is characterized by comprising:
the driving mechanism is in transmission connection with the test sample through a transmission shaft and at least used for providing rotary power for the test sample;
the rotating speed adjusting mechanism is connected with the driving mechanism and at least used for adjusting the rotating speed of the driving mechanism and keeping the rotating speed of the driving mechanism constant;
a resistive environment mechanism comprising a housing containing a fluid medium and at least for providing a resistive environment for a test sample immersed in the fluid medium;
a resistance monitoring mechanism for at least monitoring a flow transition of a fluid medium surrounding the test sample during the testing.
2. The device for testing the resistance of a fluid under high Reynolds number according to claim 1, wherein: the rotating speed adjusting mechanism comprises a rotating speed monitoring mechanism and a rotating speed adjusting mechanism, and the rotating speed monitoring mechanism is connected with the driving mechanism and the transmission shaft respectively.
3. The device for testing the resistance of a fluid under high Reynolds number according to claim 2, wherein: the rotating speed monitoring mechanism is connected with the driving mechanism through a first coupler, and the rotating speed monitoring mechanism is connected with the transmission shaft through a second coupler.
4. Device for testing the resistance in a fluid at a high reynolds number according to claim 3, wherein: the output shafts of the rotating speed monitoring mechanism, the transmission shaft and the driving mechanism are coaxially arranged, wherein the rotating speed monitoring mechanism comprises a torque sensor and a torque sensor display instrument, and the rotating speed adjusting mechanism comprises a speed regulator.
5. The device for testing the resistance of a fluid under high Reynolds number according to claim 2, wherein: the test sample is detachably arranged at one end part of the transmission shaft; and/or the test sample is in threaded connection with the transmission shaft, a locking nut is further arranged at one end of the transmission shaft, and the thread directions of the test sample and the locking nut are opposite.
6. The device for testing the resistance of a fluid under high Reynolds number according to claim 5, wherein: the test sample comprises a low density high hardness test disc; preferably, the material of the test disc comprises aluminum alloy; and/or the thickness of the test disc is more than 5mm, and the radius is more than 20 cm.
7. The device for testing the resistance of a fluid under high Reynolds number according to claim 6, wherein: the resistance monitoring mechanism comprises a laser sheet light source and a particle image velocimeter, wherein light beams emitted by the laser sheet light source are perpendicular to an appointed surface of the test sample, and the orientation of a camera of the particle image velocimeter is perpendicular to the light beams emitted by the laser sheet light source and parallel to the appointed surface of the test sample.
8. The apparatus for testing resistance under high reynolds number in fluid according to claim 7, further comprising: the supporting platform is fixed on the base body through a supporting column, and the driving mechanism and the rotating speed adjusting mechanism are fixed on the supporting platform; and/or the driving mechanism comprises a driving motor, and a positioning screw capable of adjusting the perpendicularity of an output shaft of the driving motor is arranged between the driving motor and the supporting platform; preferably, the driving motor comprises a direct current motor, the power of the direct current motor is more than 3KW, and the rotating speed is continuously adjustable within 0-5000 rpm; and/or the transmission shaft is also connected with a verticality adjusting mechanism which is fixed on the supporting platform and at least used for adjusting the verticality of the transmission shaft; preferably, the verticality adjusting mechanism comprises a horizontal fixed seat; and/or the fluid medium comprises water, and the box body is a transparent box body; preferably, the box body is a toughened glass box body.
9. The apparatus for testing resistance under high reynolds number in fluid according to claim 8, further comprising: and the control assembly is connected with the driving mechanism, the rotating speed adjusting mechanism and the resistance monitoring mechanism.
10. A method for testing resistance in fluid under a large Reynolds number is characterized by comprising the following steps:
providing a resistance test device at high reynolds number in a fluid according to any one of claims 1 to 9;
fixing a test sample on a transmission shaft, placing the test sample in a box body, and enabling the test sample to enter a fluid medium in the box body;
the test sample is rotated at different rotating speeds by adjusting the rotating speed adjusting mechanism, so that the resistance of the test sample at different rotating speeds in the fluid medium is tested;
and observing the flowing state of the fluid medium around the test sample at least through the resistance monitoring mechanism, thereby obtaining the frictional resistance mechanism of the test sample.
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| CN201910202409.4A CN111721496A (en) | 2019-03-18 | 2019-03-18 | Resistance testing device and method under high Reynolds number in fluid |
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| CN201910202409.4A CN111721496A (en) | 2019-03-18 | 2019-03-18 | Resistance testing device and method under high Reynolds number in fluid |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112858586A (en) * | 2021-01-13 | 2021-05-28 | 青岛卓润智能科技有限公司 | Rapid testing device for resistance reduction performance of large Reynolds number and detection method thereof |
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| CN112858586A (en) * | 2021-01-13 | 2021-05-28 | 青岛卓润智能科技有限公司 | Rapid testing device for resistance reduction performance of large Reynolds number and detection method thereof |
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