Determination of the parameters of suspended particles using acoustic radiation

2021 ◽  
Vol 87 (5) ◽  
pp. 27-33
Author(s):  
V. V. Semenov

The flow of a gas or liquid can be visualized by detecting and analyzing sequential images of the particle distribution on the surface of the object under study through the determination of the motion parameters. However, this approach does not provide estimation of the mass and density of solid particles along with visualization of their distribution. We present the results of determining the mass and density of suspended particles using additional irradiation of the particle flux with acoustic radiation. The technique is based on the use of the method of visual processing of images of particle flows entrained by an acoustic field of a given frequency and amplitude for at least two periods of acoustic vibrations. Relaxation of the particles in the measuring plane «cut out» by the light «knife» was also taken into account. The basic mathematical expressions required for estimation of the mass, density, velocity field and shape of the particles using digital image processing and temperature measurement in the flow area are presented. The block diagram and design of the device used for the implementation of the proposed diagnostic method are presented. This technique can be used to determine the parameters of suspended particles in medicine, biology, ecology, powder metallurgy and other fields of science and technology.

2018 ◽  
Vol 58 (3) ◽  
pp. 171 ◽  
Author(s):  
Jan Krupička ◽  
Tomáš Picek ◽  
Štěpán Zrostlík

Laser stripe measurement (LSM) is a relatively novel method for measuring a local concentration of coarse particles in a mixture with fluid. It is based on an analysis of camera records of the laser sheet penetration in to the mixture. We report on our measurements of the concentration of suspended particles in a fluidization cell and focus on the parameters affecting the evaluation procedure for the measured data. A high sensitivity of the measured concentration to the correction for the position of the wall and to the threshold brightness for data filtering is demonstrated. The uncertainty in the wall position is reduced by applying a rectification procedure based on an identification of the position of a laser stripe drawn at the wall of the fluidization cell. The main motivation for the presented study was to find guidelines for the determination of the threshold brightness, absence of which can be considered a serious weakness of the LSM when particles of non-ideal optical properties are tested. Histograms of the brightness of laser stripes drawn on a surface of suspended particles are analysed with the aim to find a connection between the histograms and the threshold brightness. The threshold brightness is shown to be proportional to a position of the second of the two peaks identified in a histogram. Based on the results of the analysis, a method is proposed for the determination of the threshold brightness.


Author(s):  
K. R. Daly ◽  
T. Roose

In this paper, we use homogenization to derive a set of macro-scale poro-elastic equations for soils composed of rigid solid particles, air-filled pore space and a poro-elastic mixed phase. We consider the derivation in the limit of large deformation and show that by solving representative problems on the micro-scale we can parametrize the macro-scale equations. To validate the homogenization procedure, we compare the predictions of the homogenized equations with those of the full equations for a range of different geometries and material properties. We show that the results differ by ≲ 2 % for all cases considered. The success of the homogenization scheme means that it can be used to determine the macro-scale poro-elastic properties of soils from the underlying structure. Hence, it will prove a valuable tool in both characterization and optimization.


2009 ◽  
Vol 71 (S208) ◽  
pp. 33c-39c
Author(s):  
Enping Chen ◽  
Jang-Hyun Chung ◽  
Per G. Söderberg ◽  
Bo Lindström
Keyword(s):  

Author(s):  
Yu. Tolchinsky ◽  
V. Ved ◽  
I. Rofe-Beketova

Mechanochemistry studies and explains the processes of chemical and physicochemical transformations that are generated by mechanical action on a substance. When carrying out deep mechanochemical transformations, as a rule, it is necessary to transfer to solid reagents a portion of energy comparable to the energy of interatomic bonds. For this, various machines and apparatus are used, such as extruders, in which mechanical energy is constantly transferred to the crushed material. The article discusses the interaction of two reagents in a simple chemical reaction in the state of a mixture of particles of two types, which occurs during compression of particles having a rough irregular shape, and colliding with each other, forming areas of contact. Significant stress concentrations and heating of the substance with the formation of a new phase arise in these regions. Thermal control of the mechanochemical reaction is to maintain an optimal balance of dissipative heat and heat from the coolant in the worm reactor so that the rate of flow and the final product of the reaction meet the specified specifications. The formulas provided in the article for calculating the coefficient of the rate of mechanochemical reaction, heat transfer between worm reactor and jacket channel, heat exchange between jacket and environment allows to calculate the balance conditions for thermal management. The block diagram of the technological line, which is presented in the article, is more economical in comparison with carrying out the same reaction in a solvent. The economic benefit lies in the elimination of the steps of introducing and removing the solvent from the reaction product. At the end, it is indicated that the mechanochemical reaction of the transformation of a mixture of two dispersed materials consisting of solid particles into a liquid can be realized in continuous conditions in a flow mode in a worm machine. And thermal control of the course of a mechanochemical reaction can be carried out using controlled heat exchange with a coolant in a jacket under conditions of turn-around spatial dispersion.


1960 ◽  
Vol 82 (3) ◽  
pp. 609-621 ◽  
Author(s):  
S. L. Soo ◽  
H. K. Ihrig ◽  
A. F. El Kouh

Experimental methods for the determination of certain statistical properties of turbulent conveyance and diffusion of solid particles in a gaseous state are presented. Methods include a tracer-diffusion technique for the determination of gas-phase turbulent motion and a photo-optical technique for the determination of motion of solid particles. Results are discussed and compared with previous analytical results.


2014 ◽  
Vol 955-959 ◽  
pp. 1204-1209
Author(s):  
Xiao Li ◽  
Xiao Man Li ◽  
Xiao Xia Yang ◽  
Qiang Li ◽  
Bin Huang ◽  
...  

An efficient and reliable analytical method has been used for determination of polybrominated diphenyl ethers (PBDEs) in atmospheric total suspended particles collected from the six state controlling air sampling sites and two self-selection sampling sites in Kunming, China. The results showed that the overall average concentrations of TSP collected from Kunming were in the range of 44.36 μg/m3 to 82.22 μg/m3. This pattern was lower than the average concentrations of Guiyu, Guangzhou and similar to Hong Kong. In TSP, the penta-BDEs and octa-BDEs were the dominant PBDEs and the PBDEs concentration ranged from 12.39 pg/m3 to 71.51 pg/m3, with a mean value of 46.82 pg/m3. This level was below the city of Guiyu, Örebro in Sweden and similar to Hong Kong, Guangzhou. The average concentrations of PBDEs had the trend of descent from the urban center to the outskirts of Kunming.


2017 ◽  
Vol 22 (2) ◽  
Author(s):  
EMILIAN MOȘNEGUȚU ◽  
VALENTIN NEDEFF ◽  
MIRELA PANAINTE-LEHĂDUȘ ◽  
NARCIS BÂRSAN ◽  
DANA CHIȚIMUȘ ◽  
...  

This article presents the methodology for determining the real values of kinematic indices which characterizes the mechanical separation of a mixture of solid particles. Mechanical separation of a mixture of solid-solid on surface provided with holes is the most common method of separation. To optimize equipment that performs this operation, both theoretical and practical characteristics are determined. Kinematic indices are part of the theoretical characteristics, helping to identify behavior of solid particles on a surface flat swing. Starting from an experimental batch, real values of the kinematic indices corresponding to up, down and sideways movement on the sieve were determined for the following types of real particles: grain, large grain beans, small grain beans and soybeans.


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