Analysis of the flow cement-sandy solution under the vibration-extrusion method of manufacturing fiber concrete products

Abstract

The vibration-extrusion method of making fibro concrete products takes into account the features of disperse reinforcement, eliminates the lacing or destruction of the fibers during mixing and forming, increases the efficiency of using fibers due to the possibility of their orientation in the product, reduces the water-cement ratio in the composition, increases the density of the final product, etc.

The proposed method for describing isothermal laminar stable flow of incompressible Newtonian fluid in converging pyramidal channels of square cross-section, which allows to make calculations of a feeder solution vibro-extrusion plant.

In considering the process, a phenomenological approach that takes a cement-sand solution, as a homogeneous isotropic medium, whose structure is limited to general warnings, is used. Due to the fact that such solution in the vibration field behaves like a liquid, the hydrodynamic theories are the most suitable for describing the process. It is taken into account that in the conditions of vibration created by standard vibrators, the solution is a pseudo Newtonian system. The flood is carried out under the action of hydrostatic pressure of the mass as a result of thixotropic reduction of the viscosity of the cement-sandy solution.

To improve the formation of a thin layer of solution, device-feeder designs have been proposed that exclude the formation of stagnant zones and provide for obtaining the harnesses of a cement-sandy solution with stable shape and quality. The delivery of the solution to the conveyor at the same time is carried out through the square cross-sectional convergent channels. There are no analytical formulas for describing the flow in such channels.

The introduction of the proposed and proposed method in the calculation of the isothermal laminar stable flow of incompressible Newtonian fluid allows us to estimate the various hydrodynamic processes in pyramidal channels at low values of the Reynolds number when there are no so-called «creeping currents». This just happens during the flow of cement-sand solution in the channels of the feeder-feeder vibro-extrusion plant.