Numerical Solution of the Transient Flow in Horizontal Cylindrical Tanks Produced by the Injection of Airwith Three Nozzles

Abstract

The numerical transient analysis of the flow generated by the injection of air in a horizontal cylinder that contains water and is open to the atmosphere, is presented. The air is introduced with three nozzles and, in front of them, two types of baffles with circular and triangular cross-section are placed. The mathematical model considers the Reynolds-Navier-Stokes equations in cylindrical coordinates for a two-phase viscous Newtonian fluid, in the turbulent regime, and the transitory state; and it is solved using the numerical finite element method. The results show the transient velocity fields in the crosssection of the container which coincides with the center of the nozzles that inject the air into the container. The behavior of azimuthal velocity along the diameter of the cylinder for different times and the aforementioned axial position is also analyzed. By comparing the fields of velocity in a steady state of the system with triangular baffles against circular ones it was found that: (a) the value of the velocity vector in the left upper part of the tank diminished 3.20%; and (b) the maximum average positive value of the azimuth velocity along the diameter of the container diminished 3.71%.