Perturbation method for heat exchange between a gas and solid particles

A. Shabani Shahrbabaki; R. Abazari

doi:10.1007/s10808-009-0129-4

THERMAL CONTROL OF MECHANOCHEMICAL REACTION

Integrated Technologies and Energy Saving ◽

10.20998/2078-5364.2021.2.01 ◽

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.

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

Journal of Applied Mathematics ◽

10.1155/2012/541348 ◽

2012 ◽

Vol 2012 ◽

pp. 1-15 ◽

Cited By ~ 2

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.

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