Velocity Measurement Of Irregular Granular Flow With Spatial Filtering Velocimetry Based On Liner CCD

There are common presence of particulate materials in natural environment and Industrial production.Particulate flows when external or internal stresses change,exhibiting the properties of a fluid that form a particle stream.The measurement of the velocity field of particle flow plays a decisive role in revealing the regularity of particle flow and thus the inherent nature of the flow.The traditional method of flow measurement is mainly contact measurement,which does not meet the needs of actual production and life.In recent years,non-intrusive measurement methods based on digital image,laser speckle and fluoroscopy have been developed.These methods have their own limitations in the measurement of particle velocity and are not suitable for the fast and accurate velocity of surface irregular flow of irregular particles measuring.However,most of the granular materials in real life and industrial production belong to the irregular particles.The traditional methods have many limitations in measuring them.Therefore,the research on the measurement method of the irregular particle velocity has very important realities significance.In this paper,we propose a new method to measure the velocity of irregular particles based on linear CCD in the rotating drum,and set up the system to measure the velocity and distribution of particles in a horizontal rotating drum.Study on Movement Characteristics of Irregular Particles in Cylinder.The main contents of this thesis are as follows:(1)Firstly,two models of theoretical research,which are common in the field of particle research,are introduced.The three modes of particle movement in the cylinder and the main factors affecting the transformation of particle movement mode are emphatically introduced.(2)The general method of particle velocity measurement in the traditional measurement technology is introduced,and the limitations of each method are analyzed.In view of the limitations of traditional measurement methods,this paper proposes to measure the velocity of particles in the drum by using the spatial filter velocity method.The linear CCD camera is used as the spatial filter device and image acquisition device.The moving particles are photographed continuously to obtain the original image.After spatial filtering,Spectrum analysis,results calculation and other operations to achieve particle velocity measurement.(3)The speed measurement principle of spatial filtering method and the filteringcharacteristic of the linear array CCD spatial filter are analyzed,and the main parameters that affect the spatial filtering characteristic are discussed.A system and device of particle velocity measurement based on linear CCD spatial filtering are designed.The linear CCD pixels are grouped and distributed to measure the particle velocity and its distribution.The differential structure is designed to reduce the base of the spatial filtering signal Components,and improve the signal-to-noise ratio of the output signal of the filter.It is proposed to use the center of gravity method for spectrum correction in the process of spatial filtering signal processing to improve the stability and accuracy of the measurement result.The validity of the system measurement results is verified through the verification experiments,the measurement accuracy of the system is evaluated,and the parameters that affect the system measurement results are optimized through experiments.(4)Particle velocity measurement system based on line array CCD spatial filtering is used to measure the velocity distribution of irregular particles.The variation of the moving velocity of irregular particles with roller rotation speed and the radial particle velocity The results show that there is an essential difference in the movement characteristics between glass beads and glass beads with different particle sizes and different shapes,which verifies the accumulation of particles during the particle movement occur.In this paper,the spatial filtering method is mainly applied to the measurement of the particle velocity distribution in the drum.An irregular particle velocity measurement system based on linear CCD spatial filtering is set up.The validity of the method is verified by experimental data.Of the measurement accuracy,strongly confirmed that the system can be used for measuring the particle velocity in the drum and its distribution.