JP2007040724A - Impulse detection method to inner wall of container and its detection system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an impulse detection method to an inner wall of a container and its detection system capable of anticipating the damage to the inner wall of the container without changing the shape of the flow path and without damaging the measurement device by an optical remote measurement. <P>SOLUTION: The impulse detection method for the inner wall of the container is the method for detecting the impulse pressure caused by the cavitation to the inner wall of the container 2, wherein a stress luminescent particle is fixed on the inner wall of the container, at the time of impulse pressure is imparted to the inner wall of the container, the radiated light from the stress luminescent particle is received for detecting the impulse on the inner wall of the container. The reception of the light is performed under the condition that the liquid is flowing in the container 2 or the liquid is stored in the container 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for detecting an impact on an inner wall of a container and a detection system thereof, and more specifically, a detection method for detecting an impact on an inner wall of a container due to the occurrence of cavitation in a liquid using stress luminescent particles, and It relates to the detection system.

Conventionally, the behavior of cavitation bubbles generated in a liquid and the generation amount thereof are examined.
Here, cavitation refers to a phenomenon in which when a pressure drops below a saturated vapor pressure due to a change in liquid movement (such as a flow velocity), the liquid is vaporized to form a cavity.
Preliminary investigation of the behavior and generation amount of these bubbles and accumulation of data can minimize the occurrence of environmental damage (erosion etc.) due to cavitation at the design stage. Is extremely important.

Therefore, in recent years, various methods for observing and measuring cavitation behavior and the like, and devices used for the method have been developed.
As a method for examining the behavior of cavitation and the like, for example, a method of directly observing with a camera or the like, a method of measuring by a light scattering method (for example, see Patent Document 1), and a method of measuring a capacitance (for example, Patent Document 2) Reference).

In order to quantify the amount of bubbles generated, two methods, a method of measuring by a light scattering method and a method of measuring a capacitance, are effective.
However, in the case of the measurement by the light scattering method, a relatively large and expensive apparatus such as a strobe or a laser light source is required.

Further, in the case of a method for measuring the capacitance, the fluid to be measured must be sandwiched between two electrodes.
In addition, when the electrode largely jumps into the tube, the channel cross-sectional shape is different from the channel when the electrode is not present, and the liquid flow changes as compared with the normal channel.

  As described above, both of the measurement method using the light scattering method and the method of measuring the capacitance have the disadvantage that the apparatus becomes complicated, and erosion due to cavitation is not directly observed. Therefore, it is difficult to predict damage (erosion) of the inner wall of the container.

  As a method for directly grasping the damage state of the inner wall of the container, a method for detecting an impact on the inner wall of the container and a detection system thereof for measuring the cavitation impact pressure using a piezoelectric sensor are known (for example, Patent Document 3). reference).

JP 2003-057164 A JP-A-7-198710 JP 2002-267484 A

However, in the method and system for detecting an impact on the inner wall of the container using the piezoelectric sensor as described above, the piezoelectric sensor disposed in the liquid is affected by the cavitation shock wave and damages the measuring apparatus itself. There was a problem.
Further, since the piezoelectric sensor itself jumps out into the flow path, a flow field different from the flow field of the normal flow path where no piezoelectric sensor exists is generated.

The present invention has been made under the above technical background.
That is, according to the present invention, by remotely measuring light, the impact on the inner wall of the container is directly detected without damaging the measuring device and without changing the shape of the flow path. It is an object of the present invention to provide a method for detecting an impact on the inner wall of a container and a detection system for the prediction.

  Thus, as a result of earnest research on the background of such problems, the present inventor has stress-luminescent particles fixed to the inner wall of the container, and stress luminescence generated when impact pressure is applied to the inner wall of the container by cavitation. It has been found that the above-mentioned problems can be solved by receiving the radiated light from the particles, and this finding has led to the completion of the present invention.

  That is, the present invention is (1) a method for detecting an impact on the inner wall of a container for detecting that an impact pressure is applied to the inner wall of the container by cavitation, wherein stress luminescent particles are fixed to the inner wall of the container, The present invention resides in a method for detecting an impact on an inner wall of a container that receives radiated light from stress luminescent particles generated when an impact pressure is applied to the inner wall of the container.

  That is, the present invention resides in (2) the method for detecting an impact on the inner wall of the container as described in (1) above, wherein the radiation light is received using an image sensor.

  That is, the present invention resides in (3) the method for detecting an impact on the inner wall of the container as described in (1) above, wherein the received light is received while the liquid flows in the container.

  That is, the present invention resides in (4) the method for detecting an impact on the inner wall of the container as described in (1) above, wherein the received light is received in a state where the liquid is stored in the container.

  That is, the present invention provides (5) an oxide in which the matrix material of the stress-stimulated luminescent particles has a stuffed tridymite structure, a three-dimensional network structure, a feldspar structure, a wurtzite structure, a spinel structure, a corundum structure, or a β-alumina structure, It exists in the detection method of the impact to the container inner wall as described in said (1) which is sulfide, carbide, or nitride.

  That is, the present invention resides in (6) the method for detecting an impact on the inner wall of the container according to the above (1), wherein the base material of the stress-stimulated luminescent particles has an α-SrAl 2 O 4 structure containing lattice defects.

  That is, the present invention relates to (7) the impact on the inner wall of the container according to (1), wherein a part of the container to which the stress-stimulated luminescent particles are fixed is made transparent and the radiated light is received through the transparent part. It exists in the detection method.

  That is, the present invention is (8) a system for detecting an impact on an inner wall of a container for detecting that an impact pressure is applied to the inner wall of the container by cavitation, the container containing a liquid in which stress luminescent particles are fixed to the inner wall And a light receiving means for receiving radiated light from stress luminescent particles generated when an impact pressure is applied to the inner wall of the container by cavitation, and a system for detecting an impact on the inner wall of the container.

  That is, the present invention resides in (9) the system for detecting an impact on the inner wall of the container as described in (8) above, wherein at least a part of the inner wall of the container to which the stress luminescent particles are fixed is made of a transparent material.

  That is, the present invention resides in (10) the system for detecting an impact on the inner wall of the container according to (8), wherein the container containing the liquid is a container through which the liquid can flow.

  That is, the present invention resides in (11) the system for detecting an impact on the inner wall of the container according to (8), wherein the container containing the liquid is a container capable of storing a liquid.

  In addition, as long as the objective of this invention is met, the structure which combined said (1) to (11) suitably is also employable.

According to the present invention, stress luminescent particles are fixed to the inner wall of the container, and radiated light from the stress luminescent particles generated when an impact pressure is applied to the inner wall of the container by cavitation is received.
Therefore, if the radiated light is received by the image sensor, the position where the impact is applied to the inner wall of the container and the degree of the impact can be accurately known.

Furthermore, since stress-stimulated luminescent particles are fixed to the inner wall of the container, the normal flow path and the cross-sectional shape of the flow path do not change, and the flow of liquid in the container is not hindered.
Without damaging the measuring apparatus and without changing the shape of the flow path, the impact on the inner wall of the container can be directly detected, and damage to the inner wall of the container can be predicted.

The best mode for carrying out the present invention will be described below with reference to the drawings.
[First embodiment]
FIG. 1 shows a first embodiment of a method and system for detecting an impact on the inner wall of a container according to the present invention.
The container in the figure is an example of a liquid circulation pipe 2 through which a liquid flows.
Here, the impact on the inner wall of the container due to the cavitation impact pressure generated in the liquid circulation pipe 2 is detected.

First, the principle of cavitation generation is briefly described for reference.
For example, in a single pipe in which a large-diameter portion and a small-diameter portion are connected via a throttle portion, when a liquid flowing through the large-diameter portion on the upstream side flows into the small-diameter portion on the downstream side through the mouth throttle portion, Since the path cross-sectional area decreases, the liquid flow rate increases, and as a result, the pressure decreases.
When this pressure drops below the saturated vapor pressure, the boiling point is low in that state, and the vaporization phenomenon similar to boiling occurs, that is, cavitation occurs.

When the liquid in which cavitation has occurred flows downstream and flows into the large diameter portion again, the flow path cross-sectional area increases, the liquid flow velocity decreases, and the pressure increases.
As a result, cavitation shrinks and disappears.
When the cavitation is reduced or eliminated, a large pressure of about several hundred atmospheres (that is, impact force) is generated.

The present invention utilizes the principle that stress-stimulated luminescent particles emit light by cavitation impact pressure when stress-stimulated luminescent particles are fixed to the inner wall of the container.
Here, the stress-stimulated luminescent particles are obtained by adding a luminescent center to a base material (see, for example, JP-A-2000-63824).
Examples of the matrix material include stuffed tridymite structure, three-dimensional network structure, feldspar structure, crystal structure with lattice defect control, wurtzite structure, spinel structure, corundum structure, β-alumina structure oxide, sulfide, carbide Alternatively, nitride can be used.

  As the emission center, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu rare earth ions, and Ti, Zr, V, Transition metal ions of Cr, Mn, Fe, Co, Ni, Cu, Zn, Nb, Mo, Ta, and W can be used.

The subscript of the chemical formula number of the material is the same as that of the particle patent and the revised version. Please refer to it.
For example, when strontium and aluminum-containing composite oxide is used as the base material, xSrO.yAl ₂ O ₃ .zMO (M is a divalent metal, Mg, Ca, Ba, x, y, and z are integers) as stress luminescent particles. XSrO.yAl ₂ O ₃ .zSiO ₂ (x, y, z are integers) may be used.
Among them, SrMgAl10O ₁₇ : Eu, (SrxBa1-x) Al ₂ O ₄ : Eu (0 <x <1), BaAl ₂ Si ₂ O ₈ : Eu, and the like are desirable.
In particular, an α-SrAl ₂ O ₄ structure containing lattice defects is preferable.

The particle diameter of the stress-stimulated luminescent particles is not particularly limited as long as it is easily dispersed uniformly throughout the polymer material.
However, if the resolution is increased and the light intensity is measured, the particle diameter is preferably small.
Specifically, the average particle diameter is preferably 50 μm or less.
In this embodiment, a polymer material and stress-stimulated luminescent particles mixed to form a paste are applied in layers to the measurement target portion to detect impact.
The polymer material is not particularly limited as long as it can strongly hold and fix the stress-luminescent particles.
For example, one-pack curable or two-pack curable acrylic resin, epoxy resin, or urethane resin can be used.

Now, the detection system of this embodiment has the measuring apparatus 1, the stress light emission layer S which fixed the stress light emission particle | grains, and the liquid distribution pipe 2 in which the transparent window 3 is provided.
The measuring device 1 has a light receiving means 4, a computing means 5, a personal computer 6, and a monitor 7.
In FIG. 1, a window 3 that is a transparent portion is provided in a part of the liquid circulation pipe 2.
The transparent portion such as the window 3 can be easily provided by using at least a part of the liquid circulation pipe 2 as a transparent material such as transparent resin or glass.

The stress luminescent layer S is formed by dispersing and applying stress luminescent particles in a polymer material.
Therefore, the stress-stimulated luminescent layer S can be formed very thin with a thickness on the order of microns, becomes translucent and the flow channel cross-sectional shape hardly changes.

When bubbles generated by cavitation disappear in the vicinity of the stress luminescent layer S, a shock wave hits the stress luminescent layer S directly.
As a result, light is emitted from the stress luminescent layer S (specifically, from the stress luminescent particles) and enters the light receiving means 4 through the transparent window 3.
The light receiving means 4 includes a condensing lens 41 and an imaging element (light receiving element) 42, and light emitted from the stress luminescent particles is received by the imaging element 42 via the condensing lens 41.

The image sensor 42 performs photoelectric conversion, and an electric signal is transmitted to the arithmetic means 5.
In the arithmetic means 5, the electric signal is A / D converted, the light intensity for each pixel of the image sensor 42 is digitized, and the data is stored in the recording medium in JPEG format, TIFF format, or the like.

In the measuring apparatus 1 shown in FIG. 1, a personal computer 6 is connected to the computing means 5, and the measurement result is displayed on a monitor 7 connected to the personal computer 6.
As a specific display form, for example, a three-dimensional display is performed with the distribution of impact pressure in the stress-stimulated luminescent layer S as the XY axis (surface along the stress luminescent layer S) and the light intensity as the Z-axis. Is called.

  Here, if the background data of the light intensity in the state where cavitation does not occur is measured in advance, the relative intensity of the impact pressure can be determined by correcting the light intensity at the time of cavitation generation using that data. It can be displayed more accurately.

According to the present invention, stress luminescent particles are fixed to the inner wall of the liquid circulation tube 2, and the emitted light from the stress luminescence particles generated when an impact pressure is applied to the inner wall of the liquid circulation tube 2 is received.
Therefore, if the radiated light is received by the image pickup device 42, the position where the impact is applied and the degree of the impact can be accurately known, and as a result, the state of destruction of the inner wall due to the impact pressure can be grasped.

Furthermore, since the stress-stimulated luminescent particles are fixed to the inner wall of the container in a layered manner, the normal flow path and the cross-sectional shape of the flow path do not change, and the liquid flow in the container is not hindered.
Without damaging the measuring apparatus and without changing the shape of the flow path, the impact on the inner wall of the container can be directly detected, and damage to the inner wall of the container can be predicted.

  In addition, when the stress light emitting layer S is relatively thick in the first embodiment described above, it is preferable that the inner wall is flush with the inner wall of the liquid circulation pipe 2 provided in a portion where a recess is formed.

[Second Embodiment]
In the first embodiment, light is received through a transparent partial window 3 formed in the liquid circulation pipe 2. However, in the second embodiment, as shown in FIG. The stress light emitting layer S is formed so as to correspond to the window 3 made transparent as a whole.
It is possible to detect that an impact pressure has been applied at any position of the liquid circulation pipe 2.
The light receiving means 4 can be moved along the liquid circulation pipe 2, and the impact state by the shock wave can be observed at a desired position.

[Third embodiment]
In the first embodiment and the second embodiment, the example in which the liquid flows in the container, that is, the example in the state in which the liquid flows in the liquid circulation pipe 2 has been described, but the example in which the liquid is stored in the container 2A. This is the third embodiment.
The detection system shown in FIG. 3 assumes a case where cavitation occurs for some reason such as the influence of ultrasonic waves in a liquid that does not flow.

Although the present invention has been described above, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the essence thereof.
For example, in the above-described embodiment, the example in which the fluid circulation pipe 2 or the container 2A is used as the container has been described. However, the present invention is not limited to this, and in short, any liquid can be accommodated or circulated. Good.

In the above-described embodiment, water is used as an example of the liquid. However, the present invention is not limited to this, and any liquid can be used as long as it generates cavitation.
Moreover, although the example of the lens and the camera is shown as the light receiving means 4, it is also possible to adopt a configuration in which the optical fiber is guided to the light receiving element.

  Hereinafter, although an example is given and explained, the present invention is not limited to these examples.

FIG. 4 shows a detection system used in an experiment for detecting the impact pressure applied to the inner wall of the container by cavitation.
As shown in the figure, the measurement apparatus 1 measured cavitation generated in a beaker 2B that is a container in which a liquid (here, water) is stored.
In this example, the same components as those in the above-described embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

This detection system includes a measuring device 1 including a light receiving means 4, a box-shaped ultrasonic generation cell 8 having a stainless steel generation container 81, and a bottom of a stainless steel generation container 81 filled with liquid (water). And a beaker 2B mounted on the vehicle.
In addition, as the ultrasonic wave generation cell 8, an SNT ultrasonic cleaner (US-1 type, 38 kHz, 80 W) was used.

A stress light emitting layer S was formed on the bottom of the beaker 2B by applying a paste in which an epoxy resin and stress light emitting particles were mixed at a weight ratio of 1: 1.
The subscript of the chemical formula number of the material is the same as that of the particle patent and the revised version. Please refer to it.
The average particle diameter of the stress luminescent particles used here is 1 μm, and the material is Sr _0.90 Eu _0.01 Al ₂ O ₄ .

When the ultrasonic generation cell 8 is turned on using the detection system as described above to generate ultrasonic vibrations, the ultrasonic vibrations are transmitted to the liquid in the generation container 81, and the cavitation also occurs in the liquid in the beaker 2B. There has occurred.
Light generated due to this cavitation was received by the light receiving means 4, and computer processing was performed via the calculation means 5.
The gate time of the light receiving means 4 was 20 ms.
The results are shown in FIGS.

  FIG. 5 shows image data before the generation of ultrasonic vibration and graph processing data (here, background data).

FIG. 6 shows the relationship between time (s) and light intensity.
This is a graph obtained by calculating the average value of the light intensity in the square area shown in FIG.

7 to 10 show images after ultrasonic vibration is generated.
Here, ultrasonic vibration is generated immediately after 86 pages (one frame).

For reference, some graph processing data is shown below.
FIGS. 11 to 15 show pages 89 (third frame), 90 pages (fourth frame), 102 pages (16th frame), 187 pages (101 frame) and 242 pages in FIGS. 7 to 10, respectively. (156th frame) data.
FIG. 16 shows the relationship between the time (horizontal axis) indicated by the number of pages and the average value (vertical axis) of light intensity (Intensity).

  The present invention can directly detect the impact on the inner wall of the container without damaging the measuring apparatus and changing the shape of the flow path, and can predict the erosion of the inner wall of the container. However, as long as the principle is utilized, it is naturally applicable to directly detect the impact of the surface of the object in the liquid.

FIG. 1 is an explanatory view showing a first embodiment of a method for detecting an impact on an inner wall of a container and a detection system thereof according to the present invention. FIG. 2 is an explanatory diagram showing a second embodiment of the method for detecting an impact on the inner wall of the container and the detection system thereof according to the present invention. FIG. 3 is an explanatory view showing a third embodiment of the method for detecting an impact on the inner wall of the container and the detection system thereof according to the present invention. FIG. 4 is an explanatory diagram showing an embodiment of the method for detecting an impact on the inner wall of the container and the detection system according to the present invention. FIG. 5 is a diagram showing the results in the example, where (a) shows image data and (b) shows the graphed data. FIG. 6 shows the relationship between time (s) and light intensity. FIG. 7 shows the results of image data (pages 86 to 93) after generating ultrasonic vibrations. FIG. 8 shows the results of image data (pages 94 to 101) after generating ultrasonic vibrations. FIG. 9 shows the results of image data (pages 102 to 109) after generating ultrasonic vibrations. FIG. 10 shows the result of image data (pages 110 to 242) after generating ultrasonic vibrations. FIG. 11 shows the result (page 89) of the graph processing data after the generation of ultrasonic vibration. FIG. 12 shows the graph processing data result (90 pages) after the generation of ultrasonic vibration. FIG. 13 shows the result (page 102) of the graph processing data after the generation of ultrasonic vibration. FIG. 14 shows the result (page 187) of the graph processing data after the generation of ultrasonic vibration. FIG. 15 shows the result (page 242) of the graph processing data after the generation of the ultrasonic vibration. FIG. 16 shows the relationship between the time (horizontal axis) indicated by the number of pages and the average value (vertical axis) of light intensity (Intensity).

Explanation of symbols

1 Measuring device 2 Container (liquid distribution pipe)
2A container 2B beaker 3 window 4 light receiving means 41 condensing lens 42 imaging element 5 computing means 6 personal computer 7 monitor 8 ultrasonic wave generating cell 81 generating container S stress light emitting layer

Claims (11)

A method for detecting an impact on the inner wall of a container for detecting that an impact pressure is applied to the inner wall of the container by cavitation,
A method for detecting an impact on an inner wall of a container, wherein stress luminescent particles are fixed to the inner wall of the container, and radiated light from the stressed luminescent particles generated when an impact pressure is applied to the inner wall of the container by cavitation is received.   2. The method for detecting an impact on the inner wall of a container according to claim 1, wherein the radiation light is received using an image sensor.   The method for detecting an impact on the inner wall of the container according to claim 1, wherein the reception of the radiated light is performed in a state where the liquid flows in the container.   2. The method for detecting an impact on an inner wall of a container according to claim 1, wherein the received light is received in a state where a liquid is stored in the container.   The matrix material of the stress-stimulated luminescent particles is an oxide, sulfide, carbide or nitride having a stuffed tridymite structure, a three-dimensional network structure, a feldspar structure, a wurtzite structure, a spinel structure, a corundum structure, or a β-alumina structure. The method for detecting an impact on the inner wall of the container according to claim 1.   The method for detecting an impact on an inner wall of a container according to claim 1, wherein the base material of the stress-stimulated luminescent particles has an α-SrAl2O4 structure including lattice defects.   The method for detecting an impact on the inner wall of the container according to claim 1, wherein a part of the container to which the stress-stimulated luminescent particles are fixed is made transparent and the radiated light is received through the transparent part. A system for detecting an impact on an inner wall of a container for detecting the impact pressure applied to the inner wall of the container by cavitation,
A container containing liquid with stress-stimulated luminescent particles fixed to the inner wall;
A light receiving means for receiving radiated light from stress luminescent particles generated when an impact pressure is applied to the inner wall of the container by cavitation;
A system for detecting an impact on the inner wall of the container.   The system for detecting an impact on the inner wall of the container according to claim 8, wherein at least a part of the inner wall of the container to which the stress luminescent particles are fixed is made of a transparent material.   The system for detecting an impact on the inner wall of the container according to claim 8, wherein the container containing the liquid is a container through which a liquid can flow.   The system for detecting an impact on an inner wall of a container according to claim 8, wherein the container containing the liquid is a container capable of storing a liquid.

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