Analysis of the influence of movement and cooling of the melt in the model of a nozzle for boundary conditions in the problem of the formation of continuous basalt fibers

Abstract

A complex study of the formation of basalt continuous fibers (BCF) is the most effective. The data obtained by experimental methods allow us to develop an adequate mathematical model of fiber formation for a theoretical study of the process of fiber formation. Description and the basic equations of mathematical model of forming of basaltic continuous fibres are presented. The initial сomponent of this model is the nozzle model. Its continuation is the jet model, from which the fiber is drawn. The nozzle model was refined, which gives a more accurate approximation to the actual conditions of motion and cooling of basaltic melts in the nozzle. Empirical expressions are proposed for calculating the average flow velocity and flow rate of basaltic melts through a nozzle. This made it possible to determine the temperature of the melts at the exit of the nozzle. Тhe influence of the initial temperature, the rheological properties of the melts, the geometric dimensions of the nozzle, the level of the melt in the feeder on the temperature of the melt at its outlet is analyzed. The greatest decrease in temperature at the exit of the nozzle is observed in melts with high viscosity. A decrease in the initial melt temperature in the fiber production interval as well as a decrease in its level in the feeder leads to more cooling of the melt in the nozzle. When the melt flows out through large diameter nozzles, it cools more strongly than in small diameter nozzles. It is shown that the initial conditions for the jet model are determined by the boundary conditions of the nozzle model at its outlet. Thus, the main operating parameters of the fiber formation affect the initial conditions in the jet model and determine the nature of the movement and cooling of the jet, as well as the stresses in it when draw out the fibers.