CN201072403Y - Device for measuring solid particle three-dimensional concentration field and velocity field in gas/solid two-phase stream - Google Patents

Abstract

The utility model discloses a device used for measuring a three-dimensional concentration field and a velocity field of solid particles in dual-phrase distribution of gas and solid. A particle flux transmitting tube is arranged in front of a high speed stereo vision system formed by a double visual angle stereoscope and a high speed video camera. Jet particles are refracted by a mirror face of the double visual angle stereoscope and two particle flux images are obtained from different angles at the same time by a single target face of the high speed video camera. After the images are input into a computer, a particle stereo image is processed by a program module that is composed of a pattern recognition arithmetic program and a three-dimensional reverse projection arithmetic program to get a transient state three-dimensional concentration field of the particles, and a series of microsecond level temporal variation particle images are processed by the program module to get a three-dimensional moving track and the three-dimensional speed field of the particles. A single-camera system is used, which results in being stable and solves complicated structure and poor synchronism of a multiple camera system.

Description

A device for measuring the three-dimensional concentration field and velocity field of solid particles in gas-solid two-phase flow

technical field

The utility model relates to a technology for analyzing three-dimensional motion characteristics of a gas-solid two-phase fluid, in particular to a device for measuring the three-dimensional concentration field and velocity field of solid particles in the gas-solid two-phase flow.

Background technique

The study of gas-solid two-phase flow is an important and cutting-edge topic in the field of turbulent flow research. At present, one of the main research directions for the trajectory of solid particles in gas-solid two-phase flow is the two-phase flow measurement technology, in which the particle image velocity measurement PIV technology And DPIV technology has been widely used and researched due to the advantages of non-contact full-field measurement, simple principle, and convenient implementation. However, the above technologies generally use a sheet light source and a single-lens photography system, which can only obtain two-dimensional projection images of solid particles in two-phase flow in three-dimensional motion, lacking a sense of three-dimensionality, so they can only be used in two-dimensional or three-dimensional flow fields. A study on the characteristics of particle motion in a section. In order to obtain real three-dimensional moving images, multiple cameras can be used to shoot from different angles. The problem of this method is that the system is complex, the investment in equipment is large, the synchronization between different cameras is difficult to grasp, and the parameters of the multi-camera system cannot be fixed. Apply this method to reconstruct There are great difficulties in the trajectory of particles in three-dimensional space.

Contents of the invention

The purpose of this utility model is to provide a method and device for analyzing and measuring the three-dimensional concentration field and velocity field of solid particles in gas-solid two-phase flow using a high-speed stereo vision system composed of a dual-view stereo mirror and a single high-speed camera.

The technical scheme that the utility model solves its technical problem adopts is:

It is divided into two parts: the hardware system and the software system. The hardware system mainly includes three parts: a dual-view stereoscopic mirror fixed in front of the high-speed camera lens, a high-speed camera for collecting images, and a background computer for image processing. The two-view stereoscopic mirror is arranged in the following way by four plane mirrors, that is, the first plane mirror, the second plane mirror, the third plane mirror and the fourth plane mirror are arranged in sequence from left to right, the first plane mirror and the second plane mirror are arranged in parallel, and the second plane mirror is arranged in parallel. The three plane mirrors and the fourth plane mirrors are arranged in parallel, the first plane mirror and the second plane mirror are placed symmetrically with the third plane mirror and the fourth plane mirror, the angle between the second plane mirror and the third plane mirror is 90 degrees, and the four plane mirrors The lens is fixed on the frame, and the dual-view stereo mirror is fixed on the camera lens as a whole; the software system is developed by Visual Studio 6.0 and MATLAB programming software.

The particle flow emission tube is placed in front of a high-speed stereo vision system composed of a dual-view stereo mirror and a high-speed camera. The jet particles are refracted by the mirror surface of the dual-view stereo mirror. A single high-speed camera target surface can simultaneously obtain particle flow images from two different angles. After the image is input into the computer, the program module composed of the pattern recognition algorithm program and the three-dimensional reverse projection algorithm program processes a three-dimensional particle image to obtain the transient three-dimensional concentration field of the particle, and the program module processes a series of microsecond time-series particle images , to get the three-dimensional trajectory of the particle and the three-dimensional velocity field.

The beneficial effect that the utility model has is:

Simultaneous acquisition of particle images from two different angles on a single high-speed camera target surface, and obtaining the three-dimensional coordinates of particles in the flow field through particle pattern recognition technology and back projection algorithm are the best solutions for analyzing gas-solid two-phase flow. This method has the following advantages:

1. Use a single camera system to simultaneously acquire particle motion images from different angles, which overcomes the problems of complex structure and poor synchronization of multi-camera systems.

2. The single-camera system is stable, providing stable parameters for the reconstruction and calculation of the particle's three-dimensional trajectory.

3. The high-precision particle pattern recognition algorithm based on sub-pixel fitting greatly improves the recognition accuracy of the corresponding two-phase particles in images from different angles, and the three-dimensional coordinates of particles in the image can be obtained through the intersection of two reverse projection surfaces from different angles.

4. Combined with microsecond-level time series coordinate changes, the three-dimensional velocity field and concentration field of particles in two-phase flow can be analyzed and studied.

Description of drawings

Figure 1 is a schematic diagram of the structure of a high-speed stereo vision system.

Fig. 2 is a diagram of the optical path of the dual-view stereoscopic mirror.

Fig. 3 is a front view of the structure of the dual-view stereoscopic mirror.

Fig. 4 is a bottom view of Fig. 3 .

Figure 5 is a flow chart of the image processing software system.

In the figure: 1. Particle flow emission tube, 2. Dual-view stereoscopic mirror, 3. High-speed camera, 4. Plane reflector, 5. Plane reflector, 6. Plane reflector, 7. Plane reflector, 8. Lens, 9, the target surface, 10, the mirror frame, 11, the light transmission hole of the double viewing angle stereoscopic mirror.

Detailed ways

As shown in Fig. 1, Fig. 2, Fig. 3, Fig. 4, the utility model is divided into two parts of hardware system and software system, and hardware system mainly comprises three parts: the double viewing angle stereoscopic mirror 2 that is fixed in front of high-speed camera lens, The high-speed video camera 3 used to collect images and the background computer for image processing, the two-view stereoscopic mirror 2 is placed and arranged in the following way by four plane mirrors, that is, the first plane mirror 4, the second plane mirror 5, the third plane mirror The plane mirror 6 and the fourth plane mirror 7 are arranged successively from left to right, the first plane mirror 4 and the second plane mirror 5 are arranged in parallel, the third plane mirror 6 and the fourth plane mirror 7 are arranged in parallel, the first plane mirror 4 and the second plane mirror 5 are arranged in parallel with the third plane mirror Both the plane mirror 6 and the fourth plane mirror 7 are symmetrically placed, the angle between the second plane mirror 5 and the third plane mirror 6 is 90 degrees, and the four plane mirror eyeglasses are fixed on the mirror frame 10, and the two-view stereoscopic mirror is integrally fixed on the On the camera lens; the software system is developed using Visual Studio 6.0 and MATLAB programming software.

As shown in Fig. 1, Fig. 2, Fig. 3 and Fig. 4, a stereo vision system is used to shoot particle jets, and a dual-view stereo mirror 2 is horizontally fixed in front of the lens of a high-speed camera 3 . The software system flowchart of the high-speed stereo vision system is shown in Figure 5. Firstly, the CCD imaging optical path model is established by using the standard grid image and the CCD parameter calibration algorithm developed based on the MATLAB platform, and the CCD optical projection matrix is obtained. Afterwards, use the high-speed stereo vision system to shoot the particle jet, and the jet particles pass through the two-view stereo mirror 2 optical path formed by four plane mirrors 4, 5, 6, and 7 shown in Fig. The light transmission hole 11 and the lens 8 of the mirror are projected on the camera CCD target surface 9 to obtain two stereoscopic images of different angles, that is, a dual-view particle moving image, and the images are imported into the computer. On the basis of obtaining the CCD optical projection matrix, the single By processing the moving image of the particle from the viewpoint, the normalized coordinates of the two-dimensional image of the particle can be obtained. Using the sub-pixel pattern recognition algorithm developed based on the VisualStudio 6.0 platform to process the dual-view particle moving image, combined with the obtained optical projection model to calculate the three-dimensional diameter depth of the particle, that is, the depth information of the particle in three-dimensional space. After obtaining the normalized coordinates of the two-dimensional image of the particle and its three-dimensional diameter and depth information, the three-dimensional coordinates of the particle are calculated using the reverse projection algorithm developed based on the VisualStudio 6.0 platform. Combined with the microsecond-level particle image sequence, the three-dimensional trajectory of the particle can be reconstructed, the three-dimensional velocity field of the particle, and the concentration field change of the particle cluster can be obtained.

Claims (1)

1. measure solid particle three-dimensional concentration field in the Dual-Phrase Distribution of Gas olid for one kind, the device of velocity field, it is characterized in that: be divided into two parts of hardware system and software systems, hardware system mainly comprises three parts: be fixed in the preceding double vision angle stereoscope (2) of high-speed camera camera lens, be used for the high-speed camera (3) of images acquired and the background computer that image is handled, described double vision angle stereoscope (2) is placed arrangement as follows by four plate plane catoptrons, i.e. first level crossing (4), second level crossing (5), the 3rd level crossing (6) and the 4th level crossing (7) are arranged in order from left to right, first level crossing (4) and second level crossing (5) are arranged in parallel, the 3rd level crossing (6) and the 4th level crossing (7) are arranged in parallel, first level crossing (4) and second level crossing (5) are placed with the 3rd level crossing (6) and both symmetries of the 4th level crossing (7), angle between second level crossing (5) and the 3rd level crossing (6) is 90 degree, four plate plane catoptron eyeglasses are fixed on the mirror holder (10), and double vision angle stereoscope overall fixed is on camera lens; Software systems adopt Visual Studio 6.0 and the exploitation of MATLAB programming software.

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