Research of hydrodynamics of gas flow filtration through a stationary layer of crushed cotton stalks (wild cotton)

Abstract

The object of this research is the hydrodynamics of the stationary layer of crushed cotton stalks. One of the most problematic areas is the influence of the physical and mechanical characteristics of the stationary layer of crushed cotton stalks on the hydrodynamics of filtration drying.

In the course of research, methods of physical and mathematical modeling are used. Sieve analysis is used to determine the granulometric composition of the polydisperse mixture of crushed cotton stalks.

The granulometric composition of the crushed stalks of cotton is determined and the graphical dependence of the percentage of each fraction is presented. The hydrodynamics of gas flow filtration through a stationary layer of crushed cotton stalks are experimentally investigated, and a graphical dependence of pressure losses on the fictitious rate of gas flow filtration is presented. It is found that pressure losses in the stationary layer of crushed cotton stalks are parabolic, which indicates the influence of both inertial and viscous components on pressure losses. The unknown coefficients of the modified Ergun equation are determined on the basis of experimental data. The correlation dependence between the experimental and theoretically calculated values is presented and it is shown that the maximum relative error is 9.6 %, which is quite acceptable for practical calculations. The results of experimental studies are also presented in the form of a graphical dependence of the Euler number on the Reynolds number. Based on the generalization of the experimental data, the calculated dependences are obtained in the form of dimensionless complexes, which describe the hydrodynamics of the gas flow filtration through a stationary layer of crushed cotton stalks. This makes it possible to predict the energy costs for creating a differential pressure, with an accuracy sufficient for practical calculations. The ratio of the experimental values of pressure losses to the theoretically calculated ones, depending on the Reynolds number, is graphically presented. It is shown that the maximum relative error does not exceed 8 %. The proposed generalizations of experimental data will make it possible to determine the energy consumption for creating a pressure drop at the design stage of the drying equipment, as well as to calculate the optimal process parameters and predict its economic feasibility.