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CN-116399438-B - Device and method for measuring sound velocity by schlieren imaging method

CN116399438BCN 116399438 BCN116399438 BCN 116399438BCN-116399438-B

Abstract

The invention discloses a device and a method for measuring sound velocity by a schlieren imaging method. The reflector, the sound field instrument, the light shield and the shooting component are sequentially arranged on the guide rail along the direction of the guide rail, the reflector linearly slides on the guide rail through the first three-dimensional adjusting frame and the first four-wheel sliding table, the sound field instrument linearly slides on the guide rail through the second four-wheel sliding table, the light shield linearly slides on the guide rail through the second three-dimensional adjusting frame and the third four-wheel sliding table, and the shooting component linearly slides on the guide rail through the third three-dimensional adjusting frame and the fourth four-wheel sliding table. The invention realizes the transformation of the standing wave schlieren imaging method for sound velocity measurement, shoots standing wave schlieren images by a mobile phone and a camera, accurately records the corresponding pixel value of the diameter of an ultrasonic probe and the corresponding pixel difference value of two adjacent antinodes of the standing wave by using schlieren image software, takes the actual diameter of the ultrasonic probe as a comparison object, and completes sound velocity measurement by calculating according to a related formula, thereby realizing accurate measurement.

Inventors

  • CHEN SHUIQIAO
  • WANG KUN

Assignees

  • 浙江大学

Dates

Publication Date
20260505
Application Date
20230327

Claims (8)

  1. 1. A device for measuring sound velocity by a schlieren imaging method, which is characterized in that: the device comprises a reflector, a sound field instrument, a light shutter (10) and a shooting component, wherein the reflector, the sound field instrument, the light shutter (10) and the shooting component are sequentially arranged on a guide rail (14) along the direction of the guide rail (14); The reflector is arranged on a first three-dimensional adjusting frame (12), the first three-dimensional adjusting frame (12) is arranged on a first four-wheel sliding table (13), and the first four-wheel sliding table (13) is arranged on a guide rail (14) and can slide freely along a straight line; the sound field instrument is arranged on a second four-wheel sliding table (16), the second four-wheel sliding table (16) is arranged on a guide rail (14) and can slide freely along a straight line, the light shield (10) is arranged on a second three-dimensional adjusting frame (20), the second three-dimensional adjusting frame (20) is arranged on a third four-wheel sliding table (21), the third four-wheel sliding table (21) is arranged on the guide rail (14) and can slide freely along a straight line, the shooting assembly is arranged on a third three-dimensional adjusting frame (22), the third three-dimensional adjusting frame (22) is arranged on a fourth four-wheel sliding table (23), and the fourth four-wheel sliding table (23) is arranged on the guide rail (14) and can slide freely along a straight line; The sound field instrument comprises a sound field instrument support (3), a screw sliding table (5), a movable platform (6), a first ultrasonic probe T1 (4), a second ultrasonic probe T2 (8) and a heating core (7), wherein the sound field instrument support (3) is arranged on a second four-wheel sliding table (16), a vertical screw sliding table (5) is arranged in the sound field instrument support (3), the movable platform (6) can move up and down and is arranged on a vertical guide rail of the screw sliding table (5) and is sleeved on a screw of the screw sliding table (5) through threads to move, the first ultrasonic probe T1 (4) is arranged on the movable platform (6) of the screw sliding table (5) and can move up and down along with the movable platform (6), the second ultrasonic probe T2 (8) is fixed on the bottom of the screw sliding table (5), and the heating core (7) is fixedly arranged between the first ultrasonic probe T1 (4) and the second ultrasonic probe T2 (8); The first ultrasonic probe T1 (4) and the second ultrasonic probe T2 (8) are arranged oppositely, and the first ultrasonic probe T1 (4) and the second ultrasonic probe T2 (8) are arranged oppositely in parallel; Signals generated by an ultrasonic power meter (15) are input into a first ultrasonic probe T1 (4) and a second ultrasonic probe T2 (8) which are parallel and opposite to each other in a sound field meter, the first ultrasonic probe T1 (4) and the second ultrasonic probe T2 (8) emit ultrasonic waves to generate an interference sound field, a movable platform (6) in the sound field meter is driven to move up and down by a program-controlled stepping meter (18), and then the first ultrasonic probe T1 (4) on the movable platform (6) is driven to move up and down, so that the distance between the two ultrasonic probes of the first ultrasonic probe T1 (4) and the second ultrasonic probe T2 (8) is changed, and a standing wave sound field is obtained; the heating core (7) is electrically connected with the adjustable thermostat (17), and a control signal output by the adjustable thermostat (17) drives the heating core (7) to heat up to heat surrounding air.
  2. 2. The apparatus for measuring sound velocity by schlieren imaging method according to claim 1, wherein: the reflector comprises a spherical mirror (2) and a spherical mirror support frame (1), wherein the spherical mirror support frame (1) is fixedly arranged on a first three-dimensional adjusting frame (12), and the spherical mirror (2) can be rotatably arranged on the side surface, close to the sound field instrument, of the spherical mirror support frame (1) in any direction and is arranged towards the sound field instrument.
  3. 3. The apparatus for measuring sound velocity by schlieren imaging method according to claim 1, wherein: the first ultrasonic probe T1 (4) and the second ultrasonic probe T2 (8) are electrically connected with an ultrasonic power meter (15), and the ultrasonic power meter (15) drives the first ultrasonic probe T1 (4) and the second ultrasonic probe T2 (8) to send out ultrasonic signals for detection; The screw sliding table (5) is electrically connected with the program-controlled stepper (18), the program-controlled stepper (18) outputs sine wave signals to drive a motor in the screw sliding table (5) to rotate and drive a screw of the screw sliding table (5) to rotate, so that a movable platform (6) arranged on a vertical guide rail of the screw sliding table (5) is driven to move up and down, and the first ultrasonic probe T1 (4) is driven to move up and down.
  4. 4. The apparatus for measuring sound velocity by schlieren imaging method according to claim 1, wherein: The light shield (10) comprises a light shielding plate (27), a light shielding plate (28) and an LED light source (9), wherein the annular light shielding plate (28) is arranged on the second three-dimensional adjusting frame (20), a circular opening (26) is formed in the center of the light shielding plate (28), a semicircular light shielding plate (27) is arranged at the lower half part of the opening (26), a semicircular through hole is formed in the upper half part of the opening (26), and the LED light source (9) is arranged on the light shielding plate (28) and is electrically connected with an LED power supply (19).
  5. 5. The apparatus for measuring sound velocity by schlieren imaging method according to claim 1, wherein: the light emitted by the LED light source (9) on the light shield (10) irradiates the spherical mirror (2) of the reflector through the sound field instrument to be reflected, the reflected light is transmitted through the sound field instrument again through adjusting the position and the direction of the spherical mirror (2) and irradiates on the light shielding plate (27) of the light shielding plate (28), and the height of the light shielding plate (27) is adjusted to enable the light to enter the camera (11) of the shooting assembly through the upper half part of the opening (26) of the light shielding plate (28) to be received; The position of the light shield (10) on the guide rail (14) is adjusted through the third four-wheel sliding table (21) so that a light beam is focused on the light barrier (27), and the upper and lower positions of the light shield (10) are adjusted through the second three-dimensional adjusting frame (20) so as to change the luminous flux entering the camera (11), so that the camera (11) acquires the schlieren image.
  6. 6. A method for measuring sound velocity by using a schlieren imaging method applied to the device of any one of claims 1 to 5, which is characterized in that the specific process is as follows: Step S1, starting an ultrasonic power meter (15), and starting the first ultrasonic probe T1 (4) and the second ultrasonic probe T2 (8) to work; s2, starting an adjustable thermostat (17), and starting heating by a heating core (7); Step S3, starting a program control stepper (18), controlling a screw in a screw sliding table (5) to rotate, and driving a first ultrasonic probe T1 (4) to move through a movable platform (6) so as to form a standing wave sound field between the first ultrasonic probe T1 (4) and a second ultrasonic probe T2 (8); S4, turning on an LED power supply (19), enabling light emitted by an LED light source (9) to irradiate a spherical mirror (2) of a reflector through a sound field instrument to reflect, enabling the reflected light to permeate the sound field instrument again through adjusting the position and the direction of the spherical mirror (2) and irradiate a light blocking plate (27) of a light blocking plate (28), enabling the light to permeate the upper half part of an opening (26) of the light blocking plate (28) again and enter a camera (11) of a shooting assembly to be received; The position and the direction of the spherical mirror (2) are regulated, so that the light reflected by the spherical mirror (2) irradiates on a light blocking plate (27) in a light blocking plate (28); The position of the light shield on the guide rail (14) is moved through the third four-wheel sliding table (21), so that the light spot irradiated on the light barrier (27) of the light shielding disc (28) is focused to form the clearest focusing point; S5, starting a camera (11) of the shooting assembly, focusing a lens of the camera (11) until a clear image is acquired on a display screen of the camera (11), and synchronously observing the image acquired by the camera (11) of the shooting assembly; s6, adjusting the up-down height position of the shading disc (28) through a second three-dimensional adjusting frame (20) until a schlieren image appears on a display screen of a camera (11) of the shooting assembly; Step S7, continuously adjusting the program control stepper (18) and further adjusting the movable platform (6) to move up and down, so as to drive the first ultrasonic probe T1 (4) above to move up and down until a schlieren image appears on a display screen of a camera (11) of the shooting assembly, and carrying out image analysis processing according to the schlieren standing wave image to obtain an acoustic wave velocity value in the air.
  7. 7. The method for measuring sound velocity by schlieren imaging according to claim 6, wherein: The step S7 specifically includes: S7.1, clicking a shooting button of camera APP software on a mobile phone (24), shooting a schlieren standing wave image, and transmitting the schlieren standing wave image shot in the mobile phone to a computer; And S7.2, opening schlieren image processing software in a computer, importing a photographed schlieren standing wave image, measuring and recording a pixel value corresponding to the diameter of the first ultrasonic probe T1 (4) in the image and a pixel difference value corresponding to two adjacent antinodes of the standing wave through the schlieren image software, substituting the two values and a known actual diameter value of the first ultrasonic probe T1 (4) into a related formula, and finally calculating the sound wave speed value in the air.
  8. 8. The method for measuring sound velocity by schlieren imaging according to claim 6, wherein: The step S7 specifically uses the following formula to obtain the sound wave velocity value v: , Wherein, the The diameter of the first ultrasonic probe T1 (4) is the actual diameter; An output frequency of the ultrasonic power meter (15); the pixel value corresponding to the diameter of the first ultrasonic probe T1 (4) in the image; The pixel difference value is corresponding to the antinode distance of two adjacent standing waves in the schlieren standing wave image.

Description

Device and method for measuring sound velocity by schlieren imaging method Technical Field The invention relates to a device and a method for measuring sound velocity in air, in particular to a device and a method for measuring sound velocity by using a schlieren imaging method, belonging to the technical field of sound velocity measurement. Background The measurement of sound velocity in air is a classical physical experiment, and has important significance in practical application, and the method for measuring sound velocity in the physical experiment is more, mainly comprises a phase difference method, a time difference method, a resonance interferometry method, a spectrum analysis method and the like. The accurate sound velocity measurement system is always valued in the field of physical experiments, so that the method for measuring the sound velocity is greatly improved. The common sound velocity measurement in a laboratory can be realized by using two ultrasonic probes, a signal generator and an oscilloscope, the technology is single, the system is simple, and the method is mainly used for learning mechanical and electrical knowledge. The invention provides a device and a method for measuring sound velocity by a schlieren imaging method, which mainly calculate sound velocity values by a method for measuring schlieren standing wave wavelength and relate to thermal, optical, electrical, mechanical and computer technical knowledge. Disclosure of Invention In order to solve the problems in the background art, the invention provides a device and a method for measuring the sound velocity by using a schlieren imaging method, which are experimental instrument systems for measuring the sound velocity by integrating thermal, optical, electrical, mechanical and computer technologies. The technical scheme adopted by the invention is as follows: 1. a device for measuring sound velocity by schlieren imaging method comprises: the device comprises a reflector, a sound field instrument, a light shutter and a shooting component, wherein the reflector, the sound field instrument, the light shutter and the shooting component are sequentially arranged on a guide rail along the direction of the guide rail; the light reflector is arranged on a first three-dimensional adjusting frame, the first three-dimensional adjusting frame is arranged on a first four-wheel sliding table, and the first four-wheel sliding table is arranged on the guide rail and can slide freely along a straight line; the sound field instrument is arranged on a second four-wheel sliding table which is arranged on a guide rail and can slide freely along a straight line, the light shield is arranged on a second three-dimensional adjusting frame which is arranged on a third four-wheel sliding table which is arranged on the guide rail and can slide freely along a straight line, the shooting component is arranged on the third three-dimensional adjusting frame which is arranged on a fourth four-wheel sliding table which is arranged on the guide rail and can slide freely along a straight line. The reflector comprises a spherical mirror and a spherical mirror support frame, wherein the spherical mirror support frame is fixedly arranged on the first three-dimensional adjusting frame, and the spherical mirror can be rotatably arranged on the side surface of the spherical mirror support frame, which is close to the sound field instrument, in any direction and is arranged towards the sound field instrument. The sound field instrument comprises a sound field instrument support, a screw sliding table, a movable platform, a first ultrasonic probe T1, a second ultrasonic probe T2 and a heating core, wherein the sound field instrument support is arranged on a second four-wheel sliding table, a vertical screw sliding table is arranged in the sound field instrument support, the movable platform can move up and down and is arranged on a vertical guide rail of the screw sliding table, and is sleeved on a screw of the screw sliding table through threads; The first ultrasonic probe T1 and the second ultrasonic probe T2 are respectively arranged in opposite directions, and the first ultrasonic probe T1 and the second ultrasonic probe T2 are arranged in parallel and opposite directions. The heating core is electrically connected with the adjustable thermostat, and a control signal output by the adjustable thermostat drives the heating core to heat up so as to heat surrounding air; The first ultrasonic probe T1 and the second ultrasonic probe T2 are electrically connected with an ultrasonic power meter, and the ultrasonic power meter drives the first ultrasonic probe T1 and the second ultrasonic probe T2 to send out ultrasonic signals for detection; The screw sliding table is electrically connected with the program-controlled stepper, the program-controlled stepper outputs sine wave signals to drive a motor in the screw sliding table to rotate and drive a screw of the screw slidin