Analysis of influence exerted by structural and regime parameters of cylindrical hydrocyclones on degassing efficiency of non-Newtonian media on the basis of regression model

Abstract

A procedure is developed for calculation of separation indicators for the degassing of liquids possessing non-Newtonian properties in a cylindrical hydrocyclone using a regression model. The effect of determining similitude numbers characterizing the degassing of non-Newtonian liquids in a cylindrical hydrocyclone and the rheologic properties of the liquid on the distribution of the extent to which gas bubbles are extracted over the height of the effective space of the hydrocyclone is analyzed. The procedure proposed for calculation of separation indicators will permit well-founded selection of structural parameters and operating regimes in the design stage of a hydrocyclone employed for the degassing of non-Newtonian liquids.Degassing of inhomogeneous liquid systems, which can be appreciably intensified in a centrifugal-force field during film flow, has come into widespread use in the chemical branch of industry. The conditions under which many chemical-engineering processes are conducted (production of suspension and emulsion polyvinyl chlorides, gaprin, biomasses, and processes, the quality of which will depend on the presence of gas bubbles in the liquid) make it possible to degas a product in hydrocyclones; this substantially reduces energy outlays, shortens the time of the process, and improves the quality of production obtained.The purpose of the present study is to analyze the effect of structural and regime parameters of a hydrocyclone on the degassing of non-Newtonian media using a regression equation derived by processing results of numerical modeling over a broad range of variation in influencing factors.The problem of the degassing of inhomogeneous liquid systems exhibiting non-Newtonian properties has been solved in many studies [1][2][3][4][5][6]; the assumptions adopted in these studies, however, are not equal to the conditions under which the processes are actually conducted in hydrocyclones, and do not therefore make it possible to obtain practically acceptable results. In [7], the problem of simulating the film flow of a non-Newtonian liquid in a cylindrical hydrocyclone was solved by the numerical method using complete equations of rheodynamics; this served as the basis for subsequent modeling of various separation processes in a hydrocyclone.A mathematical description of degassing in a hydrocyclone during the film flow of a non-Newtonian liquid with a freely forming surface, which is based on solution of a complete system of rheodynamics equations is developed in [8,9] with consideration of the liquid mass connected to the bubbles, and the effect on the bubbles in a centrifugal field of inertial and Coriolis forces.At the present time, however, widespread degassing of liquids in hydrocyclones at establishments associated with the chemical branch of industry is being suppressed by the lack of a practically acceptable and scientifically proven procedure for the engineering analysis of structural and regime parameters of the hydrocyclone as applies to a specific process.