JPH0439580Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention relates to a device for analyzing the motion state of a fluid containing particles flowing in a three-dimensional space, and is particularly applicable to pulverized coal pipes, combustion exhaust gas ducts, boilers, etc. The present invention relates to a device that suitably analyzes the three-dimensional movement of fluid in a wind box of a burner device.

(Prior art) Conventionally, devices for measuring fluid velocity include contact-type flowmeters such as pitot tubes, hot-wire flowmeters, and propeller flowmeters, and non-contact flowmeters such as laser Doppler flowmeters and ultrasonic flowmeters. Current meters are known. Contact-type current meters tend to disturb the flow field by inserting probes, making simultaneous measurement at multiple points difficult. Although non-contact current meters do not disturb the flow, simultaneous measurement at multiple points is still difficult. Further, it requires a great deal of effort to obtain the velocity distribution of a complicated three-dimensional flow using these current meters.

On the other hand, in a fluid where particles are scattered, the state of the flow field can be clarified by measuring the velocity of the particles. The method described below differs from conventional non-contact flow meters in that it visualizes the flow using particles mixed in the fluid as tracers.
This image data is used to quantitatively clarify the particle velocity, that is, the entire fluid flow field.

The first example of a device for determining particle velocity from visualized image data is one with the configuration shown in Figures 6 and 8 [Kobayashi, Saga: Analysis of flow fields by image processing: Japan Society of Mechanical Engineers, No. 604 Seminar materials (computer utilization techniques in the field of fluid engineering)]. That is, in this method, a flow field containing tracer particles is controlled by three cameras, 50a and 50, each having its exposure time controlled by an exposure time control device 52.
Shoot with b, 50c. At this time, as shown in FIG. 7, the camera 50a is exposed to light from time _t0 to time _t4 , and a trail image is photographed. The camera 50b is exposed by ΔT ₂ with a delay of Δt ₂ hours from time t ₀ ,
An instantaneous image can be obtained. The camera 50c captures an instantaneous image exposed for ΔT ₃ hours from time _t3 . That is, the camera 50b obtains a starting point image, and the camera 50c obtains an end point image. As shown in FIG. 8, these three photographs are taken again by the TV camera 54, converted into digital signals by the AD converter 5, and input to the image processing section 4. The image processing unit 4 performs signal processing according to the flow shown in FIG. 9 and calculates a velocity vector.
First, since the input image data is a grayscale image having brightness levels ranging from several tens to hundreds of levels, this data is binarized using an appropriate threshold value (image data). Next, the outline of the trail image is determined, and only the center of gravity positions are recorded for the start point and end point images (image data). Within the contour 63 of the trail image, a starting point 64,
When there is only one end point 65, the particle moves from the start point to the end point, and the time in between is t ₃ −t ₂ from FIG. 7, and 2
A dimensional velocity vector 67 is obtained.

As a second example of the prior art, the device configuration is
Although it is the same as the figure, only one camera is used, and as shown in Figure 10, a strobe is fired at the beginning of the exposure to capture the trail image, and the image at the starting point is emphasized and superimposed on the trail image. There is a way to get a photo. The photograph shown in FIG. 11 thus obtained is input into the apparatus shown in FIG. 8 in the same manner as in the first example. As in the first example, the trail image 68 and the starting point image 69 are binarized,
A contour image is obtained from the trail image, and its center of gravity is obtained from the starting point image. The starting point image and the trail image are made to correspond to each other by including only one starting point image center of gravity in the trail contour image and by ensuring that the outline of the starting point image has an appropriate shape. The travel distance of the particle is determined from the trail image, and the flow direction is determined from the starting point image, and a two-dimensional velocity vector is obtained. This second example allows the velocity vector to be obtained from just one photo, whereas the first example required three photos.

A third example is the method shown in FIG. In the first and second examples, the picture taken by the camera is taken again by the TV camera, whereas in the third example, the particles in the flow field are directly captured by the TV camera 5.
4a and 54b, input it to the trail signal processor, obtain a trail signal, and record the starting point image. From these two pieces of information, calculate the velocity vector in the same way as in the first and second examples. . In the third example, the host computer 55 is mainly used for calculations, and the external memory 56 is used for recording image data. In the third example, two TV cameras are arranged orthogonal to each other, and a three-dimensional velocity vector can be obtained.

As a fourth example, there is an unknown method shown in FIG. 13, which was filed by the applicant of the present invention with the Japan Patent Office on April 7, 1986. This method is used as a photographic device.
Using one TV camera, the state of motion of particles 8 in a space illuminated by slit light 7 is input as image data to image processing section 4, and the velocity distribution of the flow field is determined. To calculate the velocity from particle image data, as in the third example described above, a trajectory image obtained by superimposing the starting point image and the particle image data input at certain times, and the last input image The three-dimensional velocity is calculated from the three image information of the final point image using the method shown in FIG. The first input starting point gray images 40a, 40b are binarized to obtain starting point binary images 42a, 42b, and the image memory 26
Record in b. Next, the input grayscale image is also binarized and recorded in the image memory 26b'. A logical sum is obtained between the image memory 26b' in which the second binary image is recorded and the image memory 26b in which the starting point binary image is recorded and is recorded in the image memory 26b'. Here,
"Calculating a logical sum" is one of the set operations in the field of mathematics, and means an operation to obtain a union.
At this time, it is necessary to ensure that the contents of the image memory 26b in which the starting point binary image is recorded do not change. By binarizing the grayscale images that are inputted sequentially at fixed time intervals in this manner and performing a logical sum with the previous image, binary images 44a to 44d of trails are obtained. Also, from the last input image to the end point binary image 43
a, 43b are obtained.

Next, the trail binary images 44a to 44d, the starting point binary images 42a, 42b, and the trail binary image 44a
The starting point and ending point of the particle are determined from the AND of ~d and the end point binary images 43a and 43b. "Logical AND"
Like the above-mentioned disjunction, is one of the set operations in the field of mathematics, and means an operation to obtain an intersection set. If it is decided to perform a logical product between the image memory 26b and the image memory 26b' and record the result in the image memory 26b, the image memory 26 after the operation
b, the starting point binary images 42a, 42b and the trace binary images 44a to 44d are superimposed, and only the overlapping portion is extracted and recorded. At this stage,
The center of gravity of the starting point binary image 42a is the trail binary image 44a
, and the starting point of the trail 44b is 42b. It also becomes clear that trails 44c and 44d have no corresponding starting point. Similarly, the image memory 26 stores the trail binary images 44a to 44d.
An AND operation is performed between b' and the image memory 26b'' in which the end point binary images 43a and 43b are recorded, and the result is recorded in the image memory 26b''. The images recorded in the image memory 26b'' at this stage are the overlapping portions of the end point binary images 43a, 43b and the trail binary images 44a to 44d, and the end point binary image 4
It can be seen that 3a and 43b are the end points of trails 44a and 44c, respectively. It also becomes clear that the trails 44b, 44d have no corresponding end points. here,
Select only the trajectory 44a that has only one starting point and one ending point inside, and use the center of gravity positions of the starting point 42a and ending point 43a, the number of input images, and the imaging cycle to calculate the velocity vector 45 of the plane illuminated by the slit light. can be calculated. On the other hand, among the trail binary images, the trail binary image 44d that does not include either the start point or the end point enters the slit light area after the start point image shooting time and exits the area before the end point image shooting time. Since they are particles, if the thickness W of the slit light and the number of input images forming the trajectory 44d are given, the minute velocity 46 in the direction perpendicular to the illuminated planar space can be obtained. Although it is possible to set the thickness W of the slit light as a constant in advance, it is also possible to input it from the console 16 as necessary. In short, in the fourth example described above, a two-dimensional velocity vector of the slit light irradiation plane and a velocity vector perpendicular to the plane can be obtained with one TV camera. That is, a three-dimensional velocity vector is obtained.

(Problems to be solved by the invention) Among the above-mentioned conventional techniques, in the first and second examples, image data is input to the image processing unit via a photograph, and it is impossible to process it in real time, and the speed that can be obtained is Vectors are two-dimensional, and there is a problem in that they are difficult to apply to complex three-dimensional flows that involve swirling, such as jets from boiler furnaces and burners.
Also, in the third example, it can be processed in real time,
Although it is possible to measure three-dimensional flows, it requires two TV cameras, and there is a limit to the depth of focus of the TV camera, which naturally limits the size and shape of the ducts, piping, etc. that can be measured. There is. In the fourth example, the problems seen in the examples of platforms 1 to 3 are overcome, but when calculating the particle velocity in the direction perpendicular to the slit light irradiation plane, there is a sudden change in the thickness direction of the slit light irradiation plane. Errors occur for particles that change their direction of motion. That is, in the case of FIG. 15-A, the particle velocity in the direction perpendicular to the slit light irradiation plane can be calculated normally, but in the case of FIG. 15-B, an error occurs. The first method for minimizing such errors is to reduce the thickness of the slit light to reduce the probability that the particles will undergo a sudden change in direction within the slit light irradiation plane. However, the thickness of the slit light naturally has a lower limit. The second method is to change the position of the slit light irradiation device 2 in a direction perpendicular to the irradiated plane, obtain velocity distributions corresponding to each slit light irradiation device position, and then compare these velocity distributions. However, measurements that are inconsistent with the surrounding velocity vector should not be adopted. Conventionally, in this type of device, the movement of the slit light irradiation device is centered on the input, and it is extremely difficult to accurately maintain the distance and parallelism between the slit light irradiation planes that are the objects of measurement. , which also required a lot of effort.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides an apparatus for analyzing the motion of a fluid containing particles and moving in a space from the movement trajectory of the particles. A slit light irradiation device that illuminates a planar space, a photographic device that photographs the movement of particles in the irradiated planar space, a device that converts the photographed particle images into digital signals, and a digital A fluid motion analysis system comprising: an image processing unit that captures, records, and calculates the above-mentioned image signals; and a drive device that moves the slit light irradiation device or the slit light irradiation unit of the device based on the signals from the image processing unit. It provides equipment.

(Operation) When calculating the velocity of a particle that moves in a complex three-dimensional manner, after obtaining the respective velocity distributions corresponding to multiple slit light irradiation plane positions, these velocity distributions are compared, and the surrounding The movement of the slit light irradiation device, which is necessary when performing operations such as removing measured values that conflict with the velocity vector of I can do it. Furthermore, it becomes easy to maintain parallelism between the slit light irradiation planes before and after the movement. If the mutual parallelism of the slit light irradiation planes cannot be maintained, the calculated position of the velocity vector will be incorrect, and the obtained flow pattern will contain a large error.

(Example) FIG. 1 shows an example of the present invention. The present invention includes a slit light irradiation device 2 that irradiates slit light 7 into a duct 1 through which a fluid 9 containing particles 8 flows, a drive device 12 that moves the slit light irradiation device 2, and a photographing device that photographs the irradiated plane. 3. It mainly consists of an AD converter 5 and an image processing section 4. In image processing, the image to be processed is taken with a TV camera, etc., the analog signal is digitized with an AD converter, inputted to a computer, that is, recorded in memory, the desired calculation is performed, and then the analog signal is converted to analog signal with a DA converter. It is normal to convert it into a signal and output it to an output device such as a TV monitor. Therefore, as the image processing section 4,
Central Processing Unit (CPU)
Although it is also possible to use a general-purpose minicomputer device or microcomputer device that has a memory capable of recording image data, the entire system as shown in Figure 2 can be constructed using a system processor consisting of a microcomputer. Setusa 17
Image memory 2 that records images and is controlled by
An image processor 23 comprising an image processing unit 6, an image processing unit 25 for performing inter-image processing, and an address processor 24 may be connected to the system processor 17 via a system bus 19.

As the photographing device 3, a TV camera is usually used.
It is connected to an image memory 26 via an AD converter 5. Monitor TV6 is DA converter 27
It is connected to the image memory 26 via. A console display 16 is connected to the system processor 17 for system control or for inputting constant data used in the image processing process. In this example, the system bus 19 includes:
A floppy disk 21 and a fixed disk 22 can also be connected as auxiliary memory. Further, the signal output section 11 is connected to the system bus 19 . The drive device 12 of the slit light irradiation device 2 includes a control section 13 and a motor 14, and the control section 13 connects the image processing section 4 via a signal cable 29.
It is connected to the signal output section 11 inside. Motor 1
4 is usually a step motor. The rotation of the motor 14 is caused by a drive shaft 73 and a transmission mechanism 74.
This is converted into a sliding movement of the slit light irradiation device 2 located on the rail 72 of the drive device 12 via the slit light irradiation device 2 .

First, the initial position of the slit light irradiation device is set. The initial position is set by the system processor 17 based on data input in advance or based on data input from the console 16 to the drive device control unit 13 via the signal output unit 11 and signal cable 29. Issue a command and control unit 1
3 is executed by operating the motor 14 based on the command.

Next, when the slit light 7 is irradiated into the duct by the slit light irradiation device 2, the particles 8 reflect the light, so that the state of movement of the particles in the planar space having a minute thickness W can be visualized, that is, the tracer particles If you choose an appropriate one, you can visualize the flow field inside the duct. If the movement of particles in this planar space is photographed by the photographing device 3 from a direction perpendicular to the plane of the slit light, continuous instantaneous images can be obtained. The image signal of the photographing device 3 is digitized by the AD converter 5, and a plurality of images are successively input to the image memory 26 of the image processing section 4. Next, almost the same as that described above in the fourth example of the prior art,
A series of image processing operations shown in FIG. 14 are performed. 1
Upon completion of the process of calculating the velocity vectors on the two slit light irradiation planes, the system processor 17 again instructs the drive device control section 13 to move the slit light irradiation device 2 via the signal output section 11. . When the slit light irradiation device 2 is set to a new position, a particle image is photographed again and the velocity vector of the plane is calculated. This operation is repeated to check whether the velocity vector in the measurement plane of interest is consistent with the velocity vectors in the measurement planes on both sides. The method of checking is
This is performed by comparing the direction and magnitude of velocity vectors in the front, back, left, right, and top and bottom of the position of interest. In this way, if there is an abnormal value, it will not be adopted as a measured value.

In addition, as in this example, when the image processing unit 25 is independent of a plurality of image memories 26 and the system processor 17, image input and other calculations can be performed in parallel, and the slit light The movement command for the irradiation device 2 can also be issued at the time when the image input is completed. By using this method, it is possible to set the slit light irradiation device 2 to the next measurement position while executing the calculation to calculate the velocity vector, and when measuring a large number of surfaces, the total measurement time can be shortened. be able to.

A second embodiment of the invention is shown in FIG. In this embodiment, the slit light irradiation device is divided into a light emitting section 30 and a slit light irradiation section 32, which are connected by an optical transmission cable.
2 was installed. In this embodiment, the weight of the drive device 12 can be reduced, the motor 14 can be made smaller, and power consumption can be reduced. Furthermore, the light emitting section, which uses electricity as its energy source, can be separated from the fluid 9, which is advantageous from a safety standpoint.

A third embodiment of the invention is shown in FIGS. 4 and 5. The light emitting unit casing 34 surrounds the light emitter 33.
It is surrounded by a fence, but only one side is open. A shield plate 35 having a slit 36 is provided on this open surface, and the light emitted from the light emitter 33 passes through the slit 36 and becomes slit light 7.
The inside of the duct 1 is irradiated. A rack 37 is provided on a part of the shield plate 35 and is driven by the motor 14 via a pinion 38. The motor 14 is connected to the drive device control section 13 as in the first and second embodiments described above. In this example, in response to a command from the system processor 17, the shield plate 35 is finally moved to change the position of the slit light 7. In the third embodiment, the above-mentioned two
The motor 14 can be made smaller and the power consumption can be further reduced than in the two examples.

(Effects of the invention) According to the invention, when calculating the velocity of a particle that moves in a complex three-dimensional manner, after obtaining velocity distributions corresponding to a plurality of slit light irradiation plane positions,
When comparing these velocity distributions and removing measured values that are inconsistent with the surrounding velocity vectors, the movement of the slit light irradiation device, which is necessary, can be done without manual intervention.
Since it is based on a drive device controlled by an image processing section, the timing of movement is appropriate, and direction and distance can be easily controlled. Therefore, it becomes possible to shorten the time required for movement and to accurately maintain the parallelism and distance between the slit light irradiation planes before and after movement, which greatly contributes to labor saving and improvement in measurement accuracy.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram for explaining an embodiment of the present invention, FIG. 2 is a detailed diagram of the image processing device in FIG. 1, and FIG. 3 is a diagram for explaining a second embodiment of the present invention. 4 is a diagram showing the third embodiment of the present invention, FIG. 5 is a sectional view taken along line A-A' in FIG. 4, FIG. 6 is an explanatory diagram of the prior art, and FIG. FIG. 6 is an explanatory diagram of the operation of the prior art; FIG. 8 is an explanatory diagram of the prior art;
FIG. 9 is a diagram showing the processing flow in the prior art in FIG. 8, FIG. 10 is an explanatory diagram of the operation of the second example of the prior art, and FIG. Figure 12 shows the results obtained.
FIG. 13 is an explanatory diagram of the third example of the prior art, and FIG.
4 is a diagram showing the processing flow in the technique shown in FIG. 13, and FIG. 15 is a diagram showing the flow of processing in the technique shown in FIG. 13.
It is a figure which shows a part of B' cross-sectional view. 1...Duct, 2...Slit light irradiation device, 3
...Photographing device, 4...Image processing device, 5...AD
converter, 7... slit light, 8... particle, 9
... Fluid, 10 ... Flow direction, 11 ... Signal output section for the slit light irradiation device, 12 ... Drive device, 13 ... Drive device control section, 14 ... Motor,
15...Movement direction.

Claims (1)

[Scope of utility model registration request] In a device that analyzes the movement of a fluid containing particles and moving in a space based on the movement trajectory of the particles, a slit light irradiation device that irradiates a planar space with a minute thickness in the space, and a slit light irradiation device that irradiates a planar space with a minute thickness in the space, A photographing device that photographs the movement of particles, a device that converts the photographed image of the particles into a digital signal, an image processing device that captures, records, and calculates the digitalized image signal, and this image processing device. 1. A motion analysis device for a fluid containing particles and moving in space, comprising a drive device that moves a slit light irradiation device or a slit light irradiation section of the device in response to a signal from the slit light irradiation device.