KR101836674B1 - Muti­axis laser Doppler velocimeter for fluid velocity visualization - Google Patents

Abstract

The present invention relates to a multiaxial laser Doppler velocimeter, velocity measurement method and system for fluid flow visualization. And more particularly, to a laser Doppler velocimeter, comprising: a housing; A pair of first laser diodes each generating a laser of the same first specific wavelength; A pair of second laser diodes each generating a laser of the same second specific wavelength; A laser fiber provided between an end of each of the first laser diode and the second laser diode and a mounting end of the rear end of the housing; And a laser diode disposed at a front end of the housing to focus the laser oscillated in each of the pair of first laser diodes to a front side to output a flux at a point to be measured to form a focus, A condensing lens for converging the oscillated laser to the front side and outputting it to a point where a flow velocity is to be measured to form a focus; A light receiving lens for receiving and accumulating first scattered light by the laser having the first specific wavelength and second scattered light by the laser having the second specific wavelength; And a detector for detecting the first scattered light and the second scattered light integrated; Analyzing the waveform of the first scattered light detected by the first detector of the detector to analyze the velocity of the fluid in the first direction and analyzing the waveform of the second scattered light by the second detector to determine the velocity of the fluid in the second direction Axis laser Doppler velocimeter and analysis system for fluid flow visualization.

Description

[0001] The present invention relates to a multiaxis laser Doppler velocimeter, a velocity measurement method and a system for visualizing fluid velocity,

The present invention relates to a multiaxial laser Doppler velocimeter, velocity measurement method and system for fluid flow visualization.

In recent years, the development of optical measurement techniques has led to the widely used Laser Doppler Velocimeter (LDV) system, which measures the flow velocity using Doppler effect, in the flow field.

As a general measurement method for measuring the flow velocity, a probe equipped with a focusing lens is installed so that a focus is formed at a measurement position outside the flow field equipped with a visible window, and a laser is scanned to measure scattered light of the flowing particles to measure the flow velocity .

To move the measuring point, the probe is mechanically moved using a transfer device or the like. The reason why the probe is moved in accordance with the position of the measurement point is that the focusing distance of the focusing lens is fixed.

On the other hand, in the flow measurement, the flow velocity information in the boundary layer region of the flow field structure is very important in engineering. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing the velocity gradient of a boundary layer appearing on the surface of a structure in a flow field. FIG. As shown, there exists a boundary layer having a velocity gradient U (y), which is affected by the shear frictional force of the surface up to a certain region on the surface 1 of the structure. In the boundary layer (3), the velocity decreases gradually as the shear frictional force with the structure becomes closer to the structure, and the flow velocity becomes "0" at the surface (1) of the structure. There is a region having the same flow velocity U _{0 because} the influence of the shearing force of the surface is small at a position away from the surface region 3 or more from the surface. It is known that the velocity gradient is linear in the boundary bottom layer (2) region and the surface shear stress of the structure in Newtonian fluid is linearly proportional to the velocity gradient. Therefore, the accurate flow measurement in the y direction in the boundary layer is very important for information on the surface shear stress as well as the flow velocity distribution around the structure.

Since the boundary layer is adjacent to the surface of the structure and the surface shear stress and the like are required to secure a plurality of measurement points within 1 mm of the surface, a LDV system having a fine resolution is required. Therefore, the conventional LDV system or a measurement method using the LDV system There is a limit.

Recently, a compact LDV system suitable for the above applications has been developed and is gradually being used. For example, in the US, MSE has developed a mini LDV by using a semiconductor laser to miniaturize the probe, which is used to measure the boundary layer flow. In order to measure the surface shear stress of the structure closer to the surface, a measuring device dedicated to shear stress was also developed which is mounted integrally on the surface of the structure. Since the focal length of the laser focusing lens is fixed, the mechanical transporting device should still be used for mini LDV, and the measurement position is fixed when the sensor is of small size.

FIG. 2 is a conceptual diagram of a compact LDV probe, which is a typical example of such an LDV and integrates a small-output small-sized diode laser, particularly when the focal length of the focusing lens is not long. When the power 5 for generating laser is supplied to the LDV probe 4 aimed at the measurement position of the flow field, a laser is generated in the diode light generating unit 6, which is transmitted to the spectral unit 7 and the reflector 8 to be transmitted to the focusing lens 41. [ A laser focused at a measurement point a, that is, a focal distance y, forms a fringe by the focusing lens, and the suspended particles b passing through this area scatter the laser light.

This scattered light causes a frequency variation (Doppler effect) corresponding to the velocity of the suspended particles, and part of the scattered light returns and is focused by the light receiving lens 42 in the probe. The focused optical signal is transmitted to the frequency analyzer through the optical cable 43. By detecting the Doppler frequency from the jukebox analyzer, it is possible to detect the floating particles, that is, the flow rate at the measuring point.

However, such a conventional LDV speedometer measures only one specific direction of flow from one focus area to one probe. In order to measure the velocity of suspended particles at different measurement points or to measure the flow rate of suspended particles in another direction, the angles and distances must be modified by separate mechanical moving means. As a result, the volume of the apparatus becomes large, and there is a problem in fast and precise driving in transportation.

Korean Patent Publication No. 2008-0085741 Korean Patent Publication No. 1996-0008447 Korea Patent No. 1282494

SUMMARY OF THE INVENTION Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide a laser Doppler velocimeter capable of simultaneously measuring and analyzing a fluid velocity in a multi- And more particularly, to a multi-axis laser Doppler velocimeter, a velocity measurement method, and a system for visualization.

According to an embodiment of the present invention, a center wavelength of each of a plurality of scattered light scattered by a laser having a plurality of different wavelengths is detected, and a background signal canceller is provided between a plurality of detectors, And more particularly, to a multiaxial laser Doppler velocimeter, velocity measurement method, and system for fluid flow visualization.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are not intended to limit the invention to the precise form disclosed. It can be understood.

A first object of the present invention is, in a laser Doppler velocimeter, comprising: a housing; A pair of laser diodes each generating a laser beam of the same specific wavelength; A laser fiber provided between an end of each laser diode and a mounting end of a rear end of the housing; A converging lens provided at a front end of the housing for converging a laser beam oscillated in each of the laser diodes to a front side and outputting the laser beam to a point where a flow velocity is to be measured to form a focus; A light receiving lens for receiving and accumulating scattered light of the focused laser beam; And a detector for detecting integrated scattered light. The multi-axis laser Doppler velocimeter for fluid flow visualization can be achieved.

The detector may include a detector for detecting the scattered light and a background signal removing unit for absorbing a part of the scattered light to reduce noise.

A second object of the present invention is to provide a fluid velocity analysis system using a laser Doppler velocimeter, comprising: a laser Doppler velocimeter according to the first object; And a signal analyzer for analyzing the velocity of the fluid by analyzing the waveform of the scattered light detected by the detector of the speedometer. The fluid velocity analyzing system using the multiaxial laser Doppler velocimeter for fluid visualization .

A third object of the present invention is to provide a method of measuring a fluid velocity using a laser Doppler velocimeter, comprising the steps of: oscillating a laser beam of the same specific wavelength in each of a pair of laser diodes; Scanning a pair of laser beams to a focusing lens through a laser fiber provided between an end of each laser diode and a mounting end of a rear end of the housing; Focusing the laser beam oscillated in each of the laser diodes to a front side by a focusing lens provided at a front end of the housing and outputting the focused laser beam to a point where a flow velocity is to be measured to form a focus; Receiving the scattered light of the laser beam focused by the light receiving lens; Detecting scattered light integrated in the detector; And analyzing the waveform of the scattered light detected by the detector to measure and analyze the velocity of the fluid. The fluid velocity measuring method using the multi-axis laser Doppler velocimeter may be achieved.

The detecting step may be characterized in that the detector detects the scattered light and absorbs a part of the scattered light by the background signal removing unit to reduce noise.

A fourth object of the present invention is a laser Doppler velocimeter, comprising: a housing; A pair of first laser diodes each generating a first laser beam of the same first specific wavelength; A pair of second laser diodes each generating a second laser beam of the same second specific wavelength; A laser fiber provided between each of the first laser diode and the mounting end of the housing rear end, and between the mounting end of the rear end of the housing and the end of the second laser diode; A pair of first laser beams are converged to the front side and output to a point where the flow velocity is to be measured to form a focus, and the pair of second laser beams are converged to the front side to measure the flow velocity A focus lens for outputting a focus to a desired point to form a focus; A light receiving lens for receiving and accumulating first scattered light by the pair of first laser beams and second scattered light by the pair of second laser beams; And a detector for detecting the accumulated first scattered light and the second scattered light. The multi-axial laser Doppler velocimeter for fluid flow visualization can be achieved.

The detector includes a first detector that detects the first scattered light, a second detector that detects the second scattered light, and a second detector that is provided between the first detector and the second detector, And a background signal removing unit for reducing a noise by absorbing a part of the background noise.

The first detector may detect the center wavelength of the first scattered light, and the second detector may detect the center wavelength of the second scattered light.

A pair of third laser diodes, each of which generates a third laser beam having the same third specific wavelength; and a third detector, which detects the center wavelength of the third scattered light by the pair of third laser beams, And further comprising:

A pair of fourth laser diodes, each of which generates a fourth laser beam having the same fourth specific wavelength, and a fourth detector for detecting the center wavelength of the fourth scattered light by the pair of fourth laser beams, And further comprising:

A fifth object of the present invention is to provide a fluid velocity analysis system using a laser Doppler velocimeter, comprising: a laser Doppler velocimeter according to the fourth object; And analyzing the waveform of the first scattered light detected by the first detector of the speedometer to analyze the velocity of the fluid in the first direction and analyzing the waveform of the second scattered light by the second detector, And a signal analyzer for analyzing the velocity of the fluid. The fluid velocity analysis system using the multi-axis laser Doppler velocimeter for fluid flow visualization can be achieved.

A pair of third laser diodes each for generating a third laser beam having the same third specific wavelength; and a third laser diode for detecting the center wavelength of the third scattered light by the pair of third laser beams, And the signal analyzer analyzes the waveform of the third scattered light detected by the third detector of the detector to analyze the velocity of the fluid in the third direction.

A pair of fourth laser diodes for generating a fourth laser beam each having the same fourth specific wavelength; and a fourth laser diode for detecting the center wavelength of the fourth scattered light by the pair of fourth laser beams, And the signal analyzer analyzes the waveform of the fourth scattered light detected by the fourth detector of the detector to analyze the velocity of the fluid in the fourth direction.

A sixth object of the present invention is to provide a method of measuring a fluid velocity using a laser Doppler velocimeter in which a first laser beam of the same first specific wavelength is oscillated in each of a pair of first laser diodes, Oscillating a second laser beam of the same second specific wavelength in each; A pair of first laser beams and a pair of second laser beams are provided through laser fibers provided between the respective first laser diodes and the mounting ends of the rear ends of the housing and between the mounting ends of the second laser diode and the rear end of the housing, 2 scanning the laser beam to the focusing lens side; A step of converging the pair of first laser beams and the pair of second laser beams to a front side by a focusing lens provided at a front end of the housing to output the focused laser beams to a point where a flow velocity is to be measured to form a focus ; Receiving the first scattered light by the pair of first focused laser beams and the second scattered light by the pair of focused laser beams on the receiving lens; The first detector of the detector detects the central wavelength of the integrated first scattered light and the second detector detects the central wavelength of the integrated second scattered light; And the signal analyzer analyzes the waveform of the first scattered light detected by the first detector to analyze the velocity of the fluid in the first direction and analyzes the waveform of the second scattered light at the second detector, And measuring the velocity of the fluid, wherein the velocity of the fluid is measured using the multiaxial laser Doppler velocimeter.

And, in the step of oscillating the laser, a third laser beam of the same third specific wavelength is oscillated in each of the pair of third laser diodes, and in the detecting step, the third detector transmits a pair of third laser beams The signal analyzer analyzes the waveform of the third scattered light detected by the third detector and analyzes the velocity of the fluid in the third direction, .

Further, in the step of oscillating the laser, a fourth laser beam having the same fourth specific wavelength is oscillated in each of the pair of fourth laser diodes, and in the detecting step, the fourth detector is connected to the pair of fourth laser Wherein the signal analyzer analyzes the waveform of the fourth scattered light detected by the fourth detector and analyzes the velocity of the fluid in the fourth direction by detecting the central wavelength of the fourth scattered light by the beam, .

According to the embodiment of the present invention, the fluid velocity in the direction of the multi-axis can be simultaneously measured and analyzed through one laser Doppler velocimeter.

According to an embodiment of the present invention, a center wavelength of each of a plurality of scattered light scattered by a laser having a plurality of different wavelengths is detected, and a background signal canceller is provided between a plurality of detectors, Effect.

It should be understood, however, that the effects obtained by the present invention are not limited to the above-mentioned effects, and other effects not mentioned may be clearly understood by those skilled in the art to which the present invention belongs It will be possible.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate preferred embodiments of the invention and, together with the description, serve to further the understanding of the technical idea of the invention, It should not be construed as limited.
BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic flow diagram of a flow velocity distribution in a surface boundary layer of a structure in a flow field,
2 is a schematic diagram of a conventional LDV system
3 is a schematic diagram showing the configuration of a multiaxial laser Doppler velocimeter for fluid flow visualization according to an embodiment of the present invention.
Fig. 4 is an enlarged view of a portion A as a measurement region in Fig. 3,
FIG. 5 is a graph showing waveform signals according to time of scattered light,
6 is a partial forward perspective view of a multi-axis laser Doppler velocimeter for fluid flow visualization according to an embodiment of the present invention,
Figure 7 is a partial rear perspective view of a multi-axis laser Doppler velocimeter for fluid flow visualization according to an embodiment of the present invention,
8 is a partial plan view of a multi-axis laser Doppler velocimeter for fluid flow visualization according to an embodiment of the present invention,
9 is a partial front view of a multi-axis laser Doppler velocimeter for fluid flow visualization according to an embodiment of the present invention;
Figure 10 is a partial back view of a multi-axis laser Doppler velocimeter for fluid flow visualization according to an embodiment of the present invention;
11A is a front view of a detector having a first detector, a second detector, two background signal cancellers according to an embodiment of the present invention,
FIG. 11B is a front view of a detector having three background signal cancellers according to an embodiment of the present invention, a first detector, a second detector, a third detector,
12 is a schematic diagram of a measurement area irradiated with a laser diode having a first specific wavelength for measuring a velocity in a first direction according to an embodiment of the present invention;
13 is a schematic diagram of a measurement area irradiated with a laser diode having a second specific wavelength for measuring a velocity in a second direction according to an embodiment of the present invention;
14 is a schematic diagram of a measurement area irradiated with a laser diode having a third specific wavelength for measuring the velocity in the third direction according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features, and advantages of the present invention will become more readily apparent from the following description of preferred embodiments with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments disclosed herein are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art.

In this specification, when an element is on another element, it means that it can be directly formed on another element, or a third element may be interposed therebetween. Also in the figures, the thickness of the components is exaggerated for an effective description of the technical content.

Embodiments described herein will be described with reference to cross-sectional views and / or plan views that are ideal illustrations of the present invention. In the drawings, the thicknesses of the films and regions are exaggerated for an effective description of the technical content. Thus, the shape of the illustrations may be modified by manufacturing techniques and / or tolerances. Accordingly, the embodiments of the present invention are not limited to the specific forms shown, but also include changes in the shapes that are produced according to the manufacturing process. For example, the area shown at right angles may be rounded or may have a shape with a certain curvature. Thus, the regions illustrated in the figures have attributes, and the shapes of the regions illustrated in the figures are intended to illustrate specific forms of regions of the elements and are not intended to limit the scope of the invention. Although the terms first, second, etc. have been used in various embodiments of the present disclosure to describe various components, these components should not be limited by these terms. These terms have only been used to distinguish one component from another. The embodiments described and exemplified herein also include their complementary embodiments.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. The terms "comprises" and / or "comprising" used in the specification do not exclude the presence or addition of one or more other elements.

In describing the specific embodiments below, various specific details have been set forth in order to explain the invention in greater detail and to assist in understanding it. However, it will be appreciated by those skilled in the art that the present invention may be understood by those skilled in the art without departing from such specific details. In some instances, it should be noted that portions of the invention that are not commonly known in the description of the invention and are not significantly related to the invention do not describe confusing reasons to explain the present invention.

3 is a schematic diagram showing a configuration of a multi-axis laser Doppler velocimeter 100 for fluid flow visualization according to an embodiment of the present invention. 4 shows an enlarged view of a portion A as a measurement region in Fig. FIG. 5 shows a waveform signal graph according to time of scattered light.

3, the multiaxial laser Doppler velocimeter 100 for fluid flow visualization according to an embodiment of the present invention is a velocity measurement using a Doppler effect, i.e., scattered by particles (b) in a moving fluid And that the scattered light has information on the motion of the particle (b).

The velocity of the fluid is easily measured using the phenomenon that particles (b) moving in the fluid scatter the laser beam. Since most of the fluid has a lot of scattering particles (b), it is possible to measure the velocity of the fluid by measuring the frequency change of the scattered light.

A laser diode 10, a light control unit 17, a laser fiber 30, a focusing lens 41, a light receiving lens 42, a detector 50, a signal An analyzer 60, and the like.

The laser diode 10 is configured as a pair in which each generates the laser beam 11 of the same specific wavelength. Further, the output of the light irradiated through the light control unit 17 can be adjusted.

The laser fiber 30 connects between the ends of the respective laser diodes 10 and the mounting end 23 of the rear end of the housing 20.

Therefore, the laser beam 11 oscillated in each of the laser diodes 10 is converged to the front side measurement area A through the focusing lens 41 provided at the front end of the housing 20, So as to form a focus.

The integrated scattered light is transmitted to the detector 50 through the optical cable 43 to detect scattered light accumulated in the detector 50. The scattered light of the focused laser is received by the light receiving lens 42, do. The signal analyzer 60 analyzes the waveform of the scattered light detected by the detector 50 to analyze the velocity of the fluid.

As shown in FIG. 4, in the fluid velocity measurement method using the LDV method, a group of interference fringes having a constant interval generated by overlapping two coherent laser beams in the measurement region A is divided into particles b ), And measures the period of the scattered light waveform to measure the flow velocity of the particle (b).

As shown in Fig. 4, the interval d between the interference fringes generated when the two laser beams 11 having a specific wavelength? Cross each other at a certain angle? Is calculated by the following equation (1) .

[Equation 1]

When the intensity of the scattered light generated when the particle b having the velocity v passes through the interference fringe is detected through the detector 50 and the signal analyzer 60, the intensity of the scattered light generated by the laser beam 11 having the Gaussian intensity distribution 5 will be generated. Here, the time interval between the attachment of the waveform and the peak is referred to as t, and the velocity of the fluid can be measured and analyzed by the following equation (2).

&Quot; (2) "

In addition, the laser Doppler velocimeter 100 according to an embodiment of the present invention may include a plurality of pairs of laser diodes 10 to simultaneously measure fluid velocities in multiple axes directions.

6 shows a partial forward perspective view of a multi-axis laser Doppler velocimeter 100 for fluid flow visualization according to an embodiment of the present invention. 7 shows a partial rear perspective view of a multi-axis laser Doppler velocimeter 100 for fluid flow visualization according to an embodiment of the present invention. 8 is a partial plan view of a multi-axis laser Doppler velocimeter 100 for fluid flow visualization according to an embodiment of the present invention, and Fig. 9 is a cross- 10 is a partial rear view of a multi-axial laser Doppler velocimeter 100 for fluid flow visualization according to an embodiment of the present invention.

6 to 10, the housing 20 according to an embodiment of the present invention includes four fiber mounting ends 23, a focusing lens 41, and a light receiving lens 42 mounted on the rear surface of the housing 20 And the optical cable insertion hole 22, which is provided on the rear surface and into which the optical cable 43 is inserted and connected, is formed. 6 to 10, a check hole 24 is formed on a side surface of the housing 20 to form a focusing lens 41, a light receiving lens 42, a detector 50, An optical cable 43, and the like.

The multiaxial laser Doppler velocimeter 100 for fluid flow visualization according to an embodiment of the present invention comprises a pair of first laser diodes 12 and a pair of second laser diodes 14. [ Each of the pair of first laser diodes 12 generates the first laser beam 13 having the same first specific wavelength. Further, each of the pair of second laser diodes 14 generates the second laser beam 15 having the same second specific wavelength.

6 to 10, the laser fiber 30 connects each of the first laser diode 12 and the mounting end 23 and connects the ends of the respective second laser diodes 14 And the mounting end 23 of the rear end of the housing 20 is connected.

The mounting end 23 connected to the second laser diode 14 is disposed between each pair of the first laser diode 12 and the mounting end 23 connected thereto as shown in FIG. 10, the left upper mounting end 23 and the right lower mounting end 23 are connected to the first laser diode 12, and the right upper mounting end 23 and the left lower mounting end 23 are connected to each other. The mounting end 23 is connected to the second laser diode 14.

Then, the laser beam transmitted through the laser fiber 30 is irradiated to the focusing lens 41 side. That is, a pair of first laser beams 13 having a first specific wavelength oscillated in each of the pair of first laser diodes 12 are spaced apart from each other by a specific distance to converge toward the front side while passing through the focusing lens 41 And outputs it to the point (a) for measuring the flow velocity to form a focus. The first scattered light is generated by the pair of first laser beams 13, and the first scattered light is detected by the first detector 51 of the detector 50.

 On the other hand, a pair of second laser beams 15 having a second specific wavelength oscillated in each of the pair of second laser diodes 14 are spaced apart from each other by a specific distance to converge toward the front side while passing through the focusing lens 41 And outputs it to the point (a) for measuring the flow velocity to form a focus. The second scattered light is generated by the pair of second laser beams 15, and the second scattered light is detected by the second detector 52 of the detector 50.

That is, when the light receiving lens 42 receives the first scattered light by the pair of first laser beams 13 having the first specific wavelength and the second scattered light by the pair of second laser beams 15 having the second specific wavelength The first detector 51 of the detector 50 detects the first scattered light, and the second detector 52 detects the second scattered light.

11A shows a front view of a detector 50 having a first detector 51, a second detector 52 and two background signal remover 54 according to an embodiment of the present invention. 11A, the detector 50 includes a first detector 51 for detecting the first scattered light, a second detector 52 for detecting the second scattered light, a first detector 51 for detecting the second scattered light, 2 detector 52 for absorbing the first and second scattered lights to reduce the noise. The background signal removing unit 54 may be configured to detect the scattered light.

That is, the detector 50 is provided with a first detector 51 having a filter equal to the central wavelength of the first scattered light, and a second detector 52 having a filter such as the center wavelength of the second scattered light, The detector is used to remove the background signal to reduce noise.

The signal analyzer 60 analyzes the waveform of the first scattered light detected by the first detector 51 to analyze the velocity of the fluid in the first direction and analyzes the waveform of the second scattered light at the second detector 52 Thereby analyzing the velocity of the fluid in the second direction. Therefore, it is possible to simultaneously measure and analyze the fluid flow rate in two directions.

In addition, the multi-axis laser Doppler velocimeter 100 for fluid flow visualization according to an embodiment of the present invention may further include a pair of third laser diodes and a third detector 53. Each of the pair of third laser diodes generates a third laser beam having the same third specific wavelength, and the third detector 53 generates a third laser beam having a center wavelength of the third scattered light by the third laser beam having the third specific wavelength . 11B shows a front view of a detector 50 having three background signal removing units 54 according to an embodiment of the present invention, a first detector 51, a second detector 52, a third detector 53, It is.

The signal analyzer 60 analyzes the waveform of the third scattered light detected by the third detector 53 of the detector 50 to analyze the velocity of the fluid in the third direction. Accordingly, the fluid flow rate in three directions can be simultaneously measured and analyzed by this configuration.

12 is a schematic diagram of a measurement area A irradiated with a first laser beam 13 having a first specific wavelength for measuring a velocity in a first direction according to an embodiment of the present invention. 13 is a schematic diagram of a measurement area A irradiated with a second laser beam 15 having a second specific wavelength for measuring the velocity in the second direction according to an embodiment of the present invention, 14 is a schematic diagram of a measurement area A irradiated with a third laser beam 16 having a third specific wavelength for measuring the velocity in the third direction according to an embodiment of the present invention.

The pair of first laser beams 13 generated by the pair of first laser diodes 12 are converged by the focusing lens 41 to the measurement point a of the measurement region A, The first detector 51 detects the first scattered light, and the signal analyzer 60 measures and analyzes the fluid velocity in the first direction.

13, the pair of second laser beams 15 generated by the pair of second laser diodes 14 are converged by the focusing lens 41 to the measurement point A of the measurement area A a), the second detector 52 detects the second scattered light, and the signal analyzer 60 measures and analyzes the fluid velocity in the second direction.

14, a pair of third laser beams 16 generated by the pair of third laser diodes are converged by the focusing lens 41 to the measurement point a of the measurement area A The third detector 53 detects the third scattered light, and the signal analyzer 60 measures and analyzes the fluid velocity in the third direction.

Accordingly, the fluid flow rate in three directions can be simultaneously measured and analyzed by this configuration.

In one embodiment of the present invention, as described above, a pair of laser diodes is constituted of one set, two sets, and three sets so that the flow velocity can be measured in one direction, two directions, and three directions simultaneously However, it is also possible to simultaneously measure velocities in four or more directions by using a pair of laser diodes.

The present invention can also be embodied as computer-readable codes on a computer-readable recording medium. A computer-readable recording medium includes all kinds of recording apparatuses in which data that can be read by a computer system is stored. Examples of the computer-readable recording medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like, and may be implemented in the form of a carrier wave (for example, transmission over the Internet) . In addition, the computer-readable recording medium may be distributed over network-connected computer systems so that computer readable codes can be stored and executed in a distributed manner. In addition, functional programs, codes, and code segments for implementing the present invention can be easily inferred by programmers of the technical field to which the present invention belongs.

It should be noted that the above-described apparatus and method are not limited to the configurations and methods of the embodiments described above, but the embodiments may be modified so that all or some of the embodiments are selectively combined .

1: Structure surface
2: Lower boundary layer
3: In the boundary layer
4: Probe
5: Power
6: Light generating unit
7: Spectroscopy unit
8: reflector
10: Laser diode
11: laser beam
12: first laser diode
13: first laser beam
14: second laser diode
15: second laser beam
16: Third laser beam
20: Housing
21: Optical system mounting stage
22: Optical cable insertion hole
23: Mounting stage
24: OK ball
30: laser fiber
41: focusing lens
42: receiving lens
43: Optical cable
50: Detector
51: first detector
52: second detector
53: third detector
54: background signal cancellation
60: Signal Analyzer
100: Multi-Axis Laser Doppler Speedometer for fluid flow visualization

Claims (16)

delete delete delete delete delete housing;
A pair of first laser diodes each generating a first laser beam of the same first specific wavelength;
A pair of second laser diodes positioned respectively between the pair of first laser diodes and each generating a second laser beam having the same second specific wavelength;
A laser fiber provided between each of the first laser diode and the mounting end of the housing rear end, and between the mounting end of the rear end of the housing and the end of the second laser diode;
A pair of first laser beams are converged to the front side and output to a point where the flow velocity is to be measured to form a focus, and the pair of second laser beams are converged to the front side to measure the flow velocity A focus lens for outputting a focus to a desired point to form a focus;
A light receiving lens for receiving and accumulating first scattered light by the pair of first laser beams and second scattered light by the pair of second laser beams;
A detector for detecting the integrated first scattered light and the second scattered light; And
Analyzing the waveform of the first scattered light detected by the first detector of the detector to analyze the velocity of the fluid in the first direction and analyzing the waveform of the second scattered light by the second detector to analyze the velocity of the fluid in the second direction The signal analyzer comprising:
A first detector which detects the first scattered light; a second detector which detects the second scattered light; and a second detector which is provided between the first detector and the second detector for absorbing a part of the first and second scattered light, Wherein the first detector detects a center wavelength of the first scattered light and the second detector detects a center wavelength of the second scattered light, wherein the first detector detects a center wavelength of the first scattered light, and the second detector detects a center wavelength of the second scattered light. Fluid velocity analysis system using multi - axis laser Doppler velocimeter.
delete delete The method according to claim 6,
A pair of third laser diodes each for generating a third laser beam having the same third specific wavelength; and a third detector for detecting the center wavelength of the third scattered light by the pair of third laser beams Wherein the fluid velocity analyzing system comprises a multiaxial laser Doppler velocimeter for fluid visualization.
10. The method of claim 9,
A pair of fourth laser diodes each for generating a fourth laser beam of the same fourth specific wavelength; and a fourth detector for detecting the center wavelength of the fourth scattered light by the pair of fourth laser beams Wherein the fluid velocity analyzing system comprises a multiaxial laser Doppler velocimeter for fluid visualization.
delete 11. The method of claim 10,
A pair of third laser diodes each for generating a third laser beam having the same third specific wavelength; and a third detector for detecting the center wavelength of the third scattered light by the pair of third laser beams Including,
Wherein the signal analyzer analyzes the waveform of the third scattered light detected by the third detector of the detector and analyzes the velocity in the third direction of the fluid. The fluid velocity analysis using the multi-axis laser Doppler velocimeter for fluid visualization system.
13. The method of claim 12,
A pair of fourth laser diodes each for generating a fourth laser beam having the same fourth specific wavelength; and a fourth detector for detecting a center wavelength of the fourth scattered light by the pair of fourth laser beams Including,
Wherein the signal analyzer analyzes the waveform of the fourth scattered light detected by the fourth detector of the detector and analyzes the velocity of the fluid in the fourth direction. The fluid velocity analysis using the multi-axis laser Doppler velocimeter for fluid velocity visualization system.
A fluid velocity measurement method using the fluid velocity analysis system according to claim 6,
The first laser beam having the same first specific wavelength is oscillated in each of the pair of first laser diodes and the second laser beam having the same second specific wavelength is oscillated in each of the pair of second laser diodes;
A pair of first laser beams and a pair of second laser beams are provided through laser fibers provided between the respective first laser diodes and the mounting ends of the rear ends of the housing and between the mounting ends of the second laser diode and the rear end of the housing, 2 scanning the laser beam to the focusing lens side;
A step of converging the pair of first laser beams and the pair of second laser beams to a front side by a focusing lens provided at a front end of the housing to output the focused laser beams to a point where a flow velocity is to be measured to form a focus ;
Receiving the first scattered light by the pair of first focused laser beams and the second scattered light by the pair of focused laser beams on the receiving lens;
The first detector of the detector detects the central wavelength of the integrated first scattered light and the second detector detects the central wavelength of the integrated second scattered light; And
The signal analyzer analyzes the waveform of the first scattered light detected by the first detector to analyze the velocity of the fluid in the first direction and analyzes the waveform of the second scattered light at the second detector to detect the velocity of the fluid in the second direction And measuring the flow rate of the fluid by using the multiaxial laser Doppler velocimeter.
15. The method of claim 14,
In the step of oscillating the laser, a third laser beam of the same third specific wavelength is oscillated in each of the pair of third laser diodes,
In the detecting step, the third detector detects the center wavelength of the third scattered light by the pair of third laser beams,
Wherein the signal analyzer analyzes the waveform of the third scattered light detected by the third detector and analyzes the velocity of the fluid in the third direction, .
16. The method of claim 15,
In the step of oscillating the laser, a fourth laser beam having the same fourth specific wavelength is oscillated in each of the pair of fourth laser diodes,
In the detecting step, the fourth detector detects the center wavelength of the fourth scattered light by the pair of fourth laser beams,
Wherein the signal analyzer analyzes the waveform of the fourth scattered light detected by the fourth detector and analyzes the velocity of the fluid in the fourth direction, .

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