Intensification of the Foam Technology by the Energy of Electrohydrothermal Force Fields. Part 2. Regularities of Optimi
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Vol. 61, No. 4, November, 2020
INTENSIFICATION OF THE FOAM TECHNOLOGY BY THE ENERGY OF ELECTROHYDROTHERMAL FORCE FIELDS. PART 2. REGULARITIES OF OPTIMIZATION OF THE STRUCTURE OF A LIGHTWEIGHT FOAM MATERIAL UNDER THE INFLUENCE OF EHTFF1 V. N. Sokov2,4 and A. A. Kulibaev3 Translated from Novye Ogneupory, No. 7, pp. 63 – 66, July, 2020.
Original article submitted April 26, 2020. The formation of the structure of lightweight materials is governed by the complicated processes running in complex three-phase systems. We study the procedure of electric heating as a control factor guaranteeing the possibility of forced lowering of the moisture content of foam masses and the acceleration of the processes of structure formation. A model of gas pores with force vectors is proposed. The internal and external factors affecting air pores in the course of electric heating are analyzed. The thermodynamic changes in the foam system and the phenomena of heat-and-mass transfer in this system are analyzed. The state of the foam system is determined by variable parameters, such as temperature, excess pressure, and electric voltage. As a result of the complex action of electrohydrothermal force fields on the foam masses, the presence of stratification and cavities is excluded, and the macrostructure becomes homogeneous. The choice of a foaming agent according to its pH value and the electric conductivity of a solution of surfactant is substantiated. Keywords: electric heating, electrohydrothermal force field (EHTFF), model of gas-filled pores, vectors of forces, interpore partitions, coalescence, surfactants, steric effect.
of the moisture content of formed masses, acceleration of the processes of structurization, and hence, weakening of the influence of the foam stability factor. We also analyze the action of internal and external factors affecting the air-filled pores in the course of electric heating. The ratios of tensile and compressing actions upon the interpore partitions and the factors affecting these actions in the course of electric treatment vary as functions of time. The processes of electric treatment of foam masses is accompanied by the thermodynamic transformations and the phenomena of heat-and-mass transfer affecting its temperature and the volume of the gas component. After the termination of treatment, the variations of the gas component and the increase in its volume are restricted by the formed interpore partitions. In other words, the degree of pore-formation in the foam mass up to the attainment of the structural strength of membranes depends on the temperature of the mixture and pressure inside the gas bubbles. All phenomena described in what follows are observed in the early stages of structure formation, i.e., when the struc-
INTRODUCTION The formation of the structures of lightweight foam material is determined by the complex physicochemical processes of formation of three-phase heterogeneous systems of interacting continua (gaseous, liquid, and solid). In this case, as important basic characteristics of th
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