Heat Exchange and Movement of the Solid Particles in the Plasma

2016 ◽  
pp. 399-430
Author(s):  
Shi Nguyen-Kuok
Keyword(s):  
Heat Exchange ◽  
Solid Particles

THERMAL CONTROL OF MECHANOCHEMICAL REACTION

2021 ◽  
pp. 3-10
Author(s):  
Yu. Tolchinsky ◽  
V. Ved ◽  
I. Rofe-Beketova
Keyword(s):  
Heat Exchange ◽  
Block Diagram ◽  
Mechanical Energy ◽  
Thermal Control ◽  
Solid Particles ◽  
Mechanochemical Reaction ◽  
Flow Mode ◽  
Stress Concentrations ◽  
Reaction Heat ◽  
Crushed Material

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.

scholarly journals Studies on the Effects of Interphase Heat Exchange during Thermal Explosion in a Combustible Dusty Gas with General Arrhenius Reaction-Rate Laws

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
K. S. Adegbie ◽  
F. I. Alao
Keyword(s):  
Heat Exchange ◽  
Thermal Explosion ◽  
Reaction Rate ◽  
Numerical Solutions ◽  
Combustion Process ◽  
Solid Particles ◽  
Dusty Gas ◽  
Rate Laws ◽  
Fuel Droplets ◽  
Interphase Heat Exchange

A mathematical model for thermal explosion in a combustible dusty gas containing fuel droplets with general Arrhenius reaction-rate laws, convective and radiative heat losses, and interphase heat exchange between gas and inert solid particles is investigated. The objective of the study is to examine the effects of interphase heat exchange between the gas and solid particles on (i) ignition of reacting gas, (ii) accumulation of heat by the solid particles during combustion process (iii) evaporation of the liquid fuel droplets, and (iv) consumption of reacting gas concentration. The equations governing the physical model with realistic assumptions are stated and nondimensionalised leading to an intractable system of first-order coupled nonlinear differential equations, which is not amenable to exact methods of solution. Therefore, we present numerical solutions as well as different qualitative effects of varying interphase heat exchange parameter. Graphs and Table feature prominently to explain the results obtained.

Abrasive wear of polymer/steel gear drives

2008 ◽  
Vol 4 (1) ◽  
pp. 1-26
Author(s):  
Gábor Kalácska
Keyword(s):  
Wear Resistance ◽  
Abrasive Wear ◽  
Material Selection ◽  
Solid Particles ◽  
Soil Types ◽  
General View ◽  
Modern Engineering ◽  
Clean Environment ◽  
Engineering Polymers ◽  
Plastic Gears

Research was performed on the friction, wear and efficiency of plastic gears made of modern engineering polymers and their composites both in a clean environment (adhesive sliding surfaces) and in an environment contaminated with solid particles and dust (abrasive), with no lubrication at all. The purpose is to give a general view about the results of abrasive wear tests including seven soil types as abrasive media. At the first stage of the research silicious sand was applied between the meshing gears and the wear of plastic and steel gears was evaluated and analyzed from the point of different material properties (elongation at break, hardness, yield stress, modulus of elasticity) and its combinations. The different correlations between the experienced wear and material features are also introduced. At the second stage of the project the abrasive sand was replaced with different physical soil types. The abrasive wear of gears is plotted in the function of soil types. The results highlight on the considerable role of physical soil types on abrasive wear resistance and the conclusions contain the detailed wear resistance. The results offer a new tribology database for the operation and maintenance of agricultural machines with the opportunity of a better material selection according to the dominant soil type. This can finally result longer lifetime and higher reliability of wearing plastic/steel parts.

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