KR101876137B1 - 3d ldv system using 3 color and 5 beam laser - Google Patents

Abstract

In measuring the flow rate of a fluid flowing in a large cavitation, a three-color 5-line laser beam having different colors and wavelengths is emitted into a large cavitation, thereby generating three- And more particularly, to a three-dimensional laser speed measuring system using a three-color 5-line laser capable of accurately measuring a flow velocity and performing simultaneous measurement on a two-way laser beam requiring a vector analysis.

Description

TECHNICAL FIELD [0001] The present invention relates to a 3D laser speed measurement system using a three-color 5-line laser,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional laser beam measuring system using a three-color 5-line laser, and more particularly, to a three- It is possible to accurately measure the three-dimensional flow velocity in the vertical direction, the axial direction and the transverse direction of the fluid by discharging the beam into the large cavitation, and in particular, to simultaneously measure the two- And more particularly, to a three-dimensional laser speed measuring system using a three-color 5-line laser.

Generally, a wakerake equipped with a 5 - ball pipe is used for wake measurement on the propeller surface at the stern of the model in the towing tank.

At the same time, the countermeasure measurement in the towing tank is performed with the authorship test, and it is relatively easy to replace the automechanical instrument and the countermeasure measuring instrument. In a large cavitation tunnel, a cavitation test is mainly performed. In this case, since it is performed in a high-speed environment, the capacity of the driving motor and the dynamometer is large, and a separate structure is constructed and a structure is installed using a crane.

In addition, it takes about 1 day to install a large-sized cavitation tunnel with model motors with a drive motor and a dynamometer installed, and the installation time is long even in the process of installing a half-current measuring device using a 5-ball pitot tube in a large cavitation tunnel Had a problem.

On the other hand, laser velocimetry (LDV) technique measures the flow rate by using a laser beam in the process of measuring the flow rate of the reflux and fluid, so that it is possible to separately measure the reflux flow even when the model line for the cavitation test is installed. In addition, there is an advantage that the flow field is not changed since a separate device for measuring the model line half flow is not installed in the flow field.

However, in order to measure the flow rate in one direction, alignment of each laser beam is required because the two laser beams must be focused. In the case of a large cavitation tunnel, a 100 mm thick acrylic window structure and a 1.5 m water It is difficult to control and align the intensity of the laser beam.

In addition, since the flow velocity is measured only in the axial direction and the vertical direction of the fluid by using the LDV in the past, the two-dimensional flow measurement process is comparatively easy, while the lateral flow (for example, The direction of the fluid) is difficult to perform.

In order to solve the limitations and problems that arise in the process of measuring the flow velocity of a fluid using the conventional LDV, the inventor of the present invention has found that, in measuring the flow velocity of a fluid flowing in a large cavitation, The three-color 5-line laser beam is injected into the large cavitation to accurately measure the three-dimensional flow velocity in the vertical direction, the axial direction and the transverse direction of the fluid. In particular, Dimensional laser speed measuring system using a three-color 5-line laser capable of performing simultaneous measurement.

Korean Patent No. 10-1556251

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a method for measuring a flow rate of a fluid flowing in a large cavitation by discharging a three-color 5-line laser beam having different colors and wavelengths into a large cavitation, Dimensional three-dimensional 5-line laser that can perform simultaneous measurement on a two-way laser beam that requires vector analysis. Speed measurement system.

A three-dimensional laser speed measuring system using a three-color 5-line laser according to an embodiment of the present invention includes a first focusing lens positioned toward the inside of a large cavitation tunnel provided with a model propeller and emitting a plurality of laser beams, A pair of second focus lenses positioned on the same horizontal line as the first focus lens and emitting a laser beam, respectively, and a laser beam emitted from the first and second focus lenses, And a flow velocity calculation unit for measuring a period of scattered light for particles included in the fluid and calculating a flow velocity of the fluid based on the measured period.

In one embodiment, the first focal lens includes an upper laser beam and a lower laser beam respectively located in the vertical direction of the large cavitation tunnel, and a central laser beam positioned in a vertically central portion of the upper laser beam and the lower laser beam The second focus lens may include a left focus lens positioned on the left side of the center laser beam and a right focus lens positioned on the right side of the center laser beam.

In one embodiment, the flow velocity calculator measures the period of the scattered light for the particles based on the laser beam emitted from the upper laser beam and the lower laser beam, thereby measuring the vertical flow velocity of the fluid with respect to the vertical direction of the large- Can be calculated.

In one embodiment, both the upper laser beam and the lower laser beam emit a laser beam corresponding to a wavelength of a yellow color, and the central laser beam has a wavelength of green color and a color of blue And the left focus lens and the right focus lens respectively emit a laser beam corresponding to a wavelength of a blue color and a green color.

In one embodiment, the flow rate calculation unit calculates the period of the scattered light for the particles based on the laser beam emitted from each lens when the focal points of the central laser beam, the left focal lens, and the right focal lens coincide with each other The axial flow velocity and the lateral flow velocity of the fluid with respect to the axial direction and the transverse direction of the large cavitation tunnel can be calculated.

In one embodiment, the distance between the center laser beam and each of the left and right focus lenses may correspond to 250 mm.

In one embodiment, the first focus lens and the second focus lens may further include a focus coincident unit for matching the focus of each of the laser beams emitted from the first focus lens and the second focus lens.

In one embodiment, the focus aligning portion may be a charge coupled device (CCD).

In one embodiment, the focus aligning portion can match the focus of each of the upper laser beam and the lower laser beam, or the focus between the center laser beam and the left focus lens and the right focus lens.

In one embodiment, the flow rate calculator measures the period of scattered light for the particles contained in the fluid flowing in the large cavitation tunnel, wherein all particles passing through the matched focal point of the upper laser beam and the lower laser beam Can be randomly measured.

In one embodiment, the flow rate calculation unit calculates the period of the scattered light for the particles based on the laser beam emitted from each lens when the focal points of the central laser beam, the left focal lens, and the right focal lens coincide with each other The axial flow velocity and the lateral flow velocity of the fluid can be calculated by vector-analyzing the measurement result of each of the measurement periods of the scattered light of the particles measured through the left focus lens and the right focus lens at the same time.

In one embodiment, when a random mode signal for calculating the flow velocity of the fluid in the vertical direction is applied, the flow rate calculator calculates the flow rate of the fluid by using the laser beam emitted from the upper laser beam and the lower laser beam, Wherein said central laser beam and said central laser beam are separated from each other only in a vertical direction of said fluid with respect to a vertical direction of said cavitation tunnel and when a coincidence mode signal for calculating an axial flow velocity and a lateral flow velocity of said fluid is applied, The axial flow velocity and the lateral flow velocity of the fluid with respect to the axial direction and the transverse direction of the large cavitation tunnel can be separately calculated using the left focus lens and the laser beam emitted from the right focus lens.

According to an aspect of the present invention, a three-color 5-line laser beam having different colors and wavelengths is emitted into a large cavitation so that three-dimensional flow velocities in the vertical direction, the axial direction and the lateral direction of the fluid can be accurately measured And has the advantage of being capable of performing simultaneous measurement on a two-way laser beam, in particular, in which a vector analysis is required.

In addition, according to one aspect of the present invention, since only the cyan beams used in the axial and lateral flow velocity measurements are used in the simultaneous measurement mode, the time required for measuring the flow velocity is shortened.

1 is a schematic view showing a three-dimensional laser speed measuring system 100 using a three-color 5-line laser according to an embodiment of the present invention.
FIG. 2 is a front view of the arrangement of the first focus lens 110 and the pair of second focus lenses 120 shown in FIG. 1. Referring to FIG.
3 shows a state in which a flow velocity of a fluid generated at the stern of a model line in a large cavitation tunnel is measured using a three-dimensional laser velocity measuring system 100 using a three-color 5-line laser according to an embodiment of the present invention FIG.
FIG. 4 is a view showing a state in which the focus of each laser beam is not exactly matched.
5 is a view showing a state in which the focus between the laser beams is adjusted and matched with respect to one point through the focal point unit 140. FIG.

Hereinafter, preferred embodiments of the present invention will be described in order to facilitate understanding of the present invention. However, the following examples are provided only for the purpose of easier understanding of the present invention, and the present invention is not limited by the examples.

FIG. 1 is a schematic view showing a three-dimensional laser speed measuring system 100 using a three-color 5-line laser according to an embodiment of the present invention. FIG. 2 is a cross- 110 and the pair of second focus lenses 120 on the basis of the front view.

Referring to FIGS. 1 and 2, a 3D laser speed measuring system 100 using a three-color 5-line laser according to an embodiment of the present invention includes a first focus lens 110, a pair of second focus lenses 120, and a flow velocity calculating unit 130. In one embodiment, the focusing unit 140 may further include a focusing unit 140.

The first focus lens 110 is positioned toward the inside of the large cavitation tunnel in which the model propeller is installed, and has a structure capable of emitting a plurality of laser beams.

The first focus lens 110 is disposed between the upper laser beam 110a and the lower laser beam 110b and between the upper laser beam 110a and the lower laser beam 110b respectively positioned in the vertical direction of the large cavitation tunnel, And a central laser beam 110c positioned at the center in the vertical direction in FIG.

Here, the upper laser beam 110a and the lower laser beam 110b may all be applied with a lens element emitting a laser beam corresponding to a wavelength of yellow color, and the central laser beam 110c may be a green ) And a lens element that emits a laser beam corresponding to a wavelength of a blue color may be respectively applied.

At this time, since the upper laser beam 110a and the lower laser beam 110b emit laser beams in the vertical direction of the large cavitation tunnel due to their array characteristics, the velocity of the upper laser beam 110a and the lower The scattering light period of the particles in the fluid passing through the focal point of the laser beam emitted from each of the laser beams 110b is measured to thereby calculate the vertical flow velocity with respect to the vertical direction of the fluid.

Also, in one embodiment, the focal points of the upper laser beam 110a and the lower laser beam 110b may be adjusted to be coincident by the focal point unit 140. At this time, the focal point unit 140 is provided with a charge coupled device (CCD) ) May be applied.

In addition, in one embodiment, the center laser beam 110c may be positioned on the same horizontal line as the pair of second focus lenses 120, which will be described later.

The pair of second focus lenses 120 may be positioned on the same horizontal line as the center laser beam 110c among the first focus lenses 110 described above, The distance between the central laser beams 110c may be 250 mm.

The second focal lens 120 includes a left focal lens 120a located 250 mm from the left side of the center laser beam 110c and a right focal lens 120b located 250 mm from the right side of the center laser beam 110c. (120b).

Here, the left focus lens 120a may be a lens element that emits a laser beam corresponding to a wavelength of a blue color, and the right focus lens 120b may be a laser that emits a laser corresponding to a wavelength of a green color A lens element for emitting a beam can be applied.

At this time, the left focus lens 120a, the center laser beam 110c, and the right focus lens 120b are positioned on the same horizontal line, and the left focus lens 120a, the center laser beam The focus of the laser beam emitted from each of the right focus lens 110c and the right focus lens 120b can be matched.

Since the left focus lens 120a, the center laser beam 110c and the right focus lens 120b emit laser beams in the transverse direction of the large cavitation tunnel due to their array characteristics, the flow velocity calculator 130 ) Measures the scattering light period of the particles in the fluid passing through the focus of the laser beam emitted from each of the left focus lens 120a, the center laser beam 110c and the right focus lens 120b, The flow rate of the fluid in the axial direction and the flow rate in the transverse direction are calculated.

Here, the left focus lens 120a, the center laser beam 110c, and the right focus lens 120b emit three laser beams having different colors and wavelengths toward the same horizontal plane as they emit laser beams toward the coincident focus, respectively The flow rate calculator 130 simultaneously measures the period of the scattered light for the particles passing through the focus of the three laser beams to obtain measurement data and obtains measurement data of the wavelength of the green color The flow rate of the fluid can be calculated by analyzing the vector of the velocity of each of the measurement data measured from the laser beam corresponding to the wavelength of the laser beam and the wavelength of the blue color.

At this time, the flow rate calculator 130 measures the period of scattered light for the particles contained in the fluid flowing in the large cavitation tunnel, and measures the vertical flow velocity component of the large cavitation tunnel by using the upper laser beam 110a and the lower laser beam 110a, Since the beam 110b has no correlation with other velocity components, the scattered light of all the particles is randomly measured with respect to the particles passing through the matched foci of the upper laser beam 110a and the lower laser beam 110b. The measurement can be performed through the mode.

For this purpose, when a random mode signal for calculating the flow velocity of the fluid in the vertical direction is applied, the flow rate calculator 130 calculates the flow rate of the laser beam 110a and the laser beam 110b emitted from the upper side laser beam 110a and the lower side laser beam 110b, The vertical flow velocity of the fluid with respect to the vertical direction of the large-sized cavitation tunnel is separately calculated.

On the other hand, since the flow velocity in the axial direction and the lateral direction of the large cavitation tunnel must be simultaneously measured in the two-direction flow velocity at the same particle (particle), the focus for the two-directional laser beam must coincide with each other. It becomes impossible to measure the flow velocity in the axial direction and the lateral direction.

Therefore, when the focal points of the left focal lens 120a, the center laser beam 110c, and the right focal lens 120b are all coincident with each other, the flow velocity calculating unit 130 calculates the flow velocity of the particle based on the laser beam emitted from each lens The laser beam corresponding to the wavelength of the blue color and the laser beam corresponding to the wavelength of the green color are highly correlated with each other so as to perform vector analysis of the respective velocities, In matching the focal points by using the collimator 140, the laser beams corresponding to the wavelength of the green color and the laser beam corresponding to the wavelength of the blue color are made to coincide with each other.

Further, in one embodiment, each time the measurement data measured through the laser beam corresponding to the wavelength of the green color and the laser beam corresponding to the wavelength of the blue color is acquired, the flow rate calculation unit 130 The measured data is replaced with the axial flow velocity and the lateral flow velocity in real time.

For this purpose, the flow velocity calculator 130 calculates the flow velocity of the fluid through the left focal lens 120a, the center laser beam 110c, and the center focal lens 120a when a coincidence mode signal for calculating the axial flow velocity and the lateral flow velocity is applied, The axial flow velocity and the lateral flow velocity of the fluid with respect to the axial direction and the transverse direction of the large cavitation tunnel are separately calculated using the laser beam emitted from the right focal lens 120b.

At this time, simultaneous measurement may be difficult if the focuses of the five laser beams are not all matched. If the focus is not perfectly matched, the two-directional and three-directional simultaneous measurement modes can cause a large difference in measurement time. Directional laser beam to perform simultaneous measurement.

3 shows a state in which a flow velocity of a fluid generated at the stern of a model line in a large cavitation tunnel is measured using a three-dimensional laser velocity measuring system 100 using a three-color 5-line laser according to an embodiment of the present invention FIG.

3, a model line is installed inside the large-sized cavitation tunnel. In order to measure the flow rate of the current generated at the stern of the model line, the current from the central laser beam 110c corresponds to the wavelength of the green color And the laser beam corresponding to the wavelength of the blue color is emitted in the direction perpendicular to the large cavitation tunnel. A laser beam corresponding to a wavelength of a blue color and a laser beam corresponding to a wavelength of a green color are respectively emitted from the left and right focus lenses 120a and 120b located on both sides of the central laser beam 110c It can be seen that as the laser beam is emitted, it is emitted towards the same horizontal plane through the focused focus.

This is because the turbulence intensity generated from the upper surface of the stern propeller shaft of the model line is high and the measurement range of the lateral flow velocity is very wide. Therefore, the left focus lens 120a, the center laser beam 110c and the right focus lens 120b So as to effectively measure the axial flow velocity and the lateral flow velocity.

FIG. 4 is a view showing a state in which the focal points of respective laser beams are not exactly aligned. FIG. 5 is a view showing a state in which the focal points of the respective laser beams are adjusted with respect to one point via the focal point unit 140, Fig.

Referring to FIG. 4, in the process of matching the focuses of five laser beams corresponding to three colors and wavelengths, a thickness difference of about 2 mm may be obtained in the case of the acrylic window thickness 100t of the large cavitation tunnel . At this time, since the diameter of the laser beam at the focal point corresponds to about 0.2 mm, the focal point does not coincide precisely even if it is deviated only by 0.1 mm. Therefore, in order to accurately measure the three-dimensional flow velocity, an acrylic window having a thickness error of 0.2 mm is required, but this is not practical in practice.

As shown in FIG. 5, even if some regions of the three types of laser beams focus on each other at one point by using a CCD device, the focus may deviate from other positions as shown in FIG. 4 due to the difference in thickness of the acrylic window .

Accordingly, in the present invention, in the course of matching the focuses of five laser beams corresponding to three colors and wavelengths, the vertical flow velocity is calculated using only the laser beam corresponding to the wavelength of the yellow color, The laser beams emitted from the left focus lens 120a, the center laser beam 110c and the right focus lens 120b positioned on the horizontal line toward the same horizontal plane are made to coincide with each other, The axial flow velocity and the lateral flow velocity are obtained by performing a vector analysis based on the measured period.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as defined in the following claims. It can be understood that it is possible.

100: 3D Laser Velocity Measurement System using 3-color 5-line laser
110: first focus lens
110a: upper side laser beam
110b: Lower laser beam
110c: central laser beam
120: second focus lens
120a: Left focus lens
120b: right focus lens
130:
140: Focus on the cheek

Claims (12)

A first focusing lens positioned to face the inside of the large cavitation tunnel with the model propeller installed therein and emitting a plurality of laser beams;
A pair of second focus lenses positioned on the same horizontal line as the first focus lens and each emitting a laser beam; And
Measuring a period of scattered light for particles included in a fluid flowing in the large cavitation tunnel by using a laser beam emitted from the first and second focus lenses, Wherein the three-dimensional five-ray laser is used to measure the three-dimensional laser velocity.
The method according to claim 1,
Wherein the first focus lens comprises:
An upper laser beam and a lower laser beam respectively positioned in the vertical direction of the large cavitation tunnel; And
And a central laser beam positioned at a central portion in the vertical direction of the upper laser beam and the lower laser beam,
The second focal lens may include:
A left focus lens positioned on the left side of the central laser beam; And
And a right-side focus lens positioned on the right side of the center laser beam.
3. The method of claim 2,
The flow rate calculation unit may calculate,
Characterized in that the vertical flow velocity of the fluid with respect to the vertical direction of the large cavitation tunnel is calculated by measuring the period of the scattered light for the particle on the basis of the laser beam emitted from the upper laser beam and the lower laser beam Three - Dimensional Laser Velocity Measurement System Using Color 5 - Wire Laser.
3. The method of claim 2,
The upper laser beam and the lower laser beam emit a laser beam corresponding to a wavelength of a yellow color,
The central laser beam simultaneously emits a laser beam corresponding to a wavelength of a green color and a wavelength of a blue color,
Wherein the left focus lens and the right focus lens respectively emit a laser beam corresponding to a wavelength of a blue color and a green color, .
5. The method of claim 4,
The flow rate calculation unit may calculate,
Wherein a period of scattered light for the particle is simultaneously measured based on a laser beam emitted from each lens when the focal points of the central laser beam, the left focal lens, and the right focal lens coincide with each other, Wherein the axial flow velocity and the lateral flow velocity of the fluid with respect to the direction and the lateral direction of the fluid are calculated.
3. The method of claim 2,
Wherein the distance between the center laser beam and the left and right focal lenses is 250 mm.
3. The method of claim 2,
Further comprising a focal point unit that focal points of the laser beams emitted from the first focus lens and the second focal lens are coincident with each other.
8. The method of claim 7,
Wherein the focus-
Characterized in that a charge coupled device (CCD) is applied to the three-dimensional 5-line laser.
8. The method of claim 7,
Wherein the focus-
The focal points of the upper laser beam and the lower laser beam are matched,
Wherein the focus of the center laser beam is made to coincide with the focus of the left focus lens and the right focus lens.
10. The method of claim 9,
The flow rate calculation unit may calculate,
Measuring a period of scattered light for the particles included in the fluid flowing in the large cavitation tunnel and randomly measuring a period of scattered light of all the particles passing through the focused laser beam and the bottom focused laser beam Wherein the three-dimensional 5-line laser is used to measure a three-dimensional laser velocity.
6. The method of claim 5,
The flow rate calculation unit may calculate,
Wherein a period of scattered light for the particle is simultaneously measured based on a laser beam emitted from each lens when the focal points of the central laser beam, the left focal lens, and the right focal lens coincide with each other,
Wherein the axial flow velocity and the lateral flow velocity of the fluid are calculated by vector-analyzing the respective measurement results of the periods of the scattered light of the particles measured through the left focus lens and the right focus lens, Three - Dimensional Laser Velocity Measurement System Using.
3. The method of claim 2,
The flow rate calculation unit may calculate,
Wherein when a random mode signal for calculating a vertical flow velocity of the fluid is applied, the laser beam emitted from the upper laser beam and the lower laser beam is used to transmit the fluid to the vertical direction of the large cavitation tunnel Only the vertical direction flow velocity of the gas is separately calculated,
Wherein when a coincidence mode signal for calculating the axial flow velocity and the lateral flow velocity of the fluid is applied, the laser beam emitted from the central laser beam, the left focus lens, Characterized in that only the axial flow velocity and the transverse flow velocity of the fluid with respect to the axial direction and the transverse direction of the cavitation tunnel are calculated separately.

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