Study of mixed convection flow around a falling spherical object within water filled vertical tube

Abstract

A numerical investigation is done for unsteady motion of a solid spherical object within water filled vertical tube. An important natural phenomenon that occurs in many industrial processes is the sedimentation and falling of solid objects in gases and liquids. Primarily, sedimentation results from a tendency of suspended objects in fluids to settle and come to rest, due to the forces acting on them through the fluid. This thesis presents numerical investigation into the solution of laminar and turbulent mixed convective heat transfer in flow around a falling spherical object within water filled vertical tube. In this thesis, the behavior of falling spherical object within a water filled vertical tube is investigated by using Finite Element Method (FEM). The influence of physical parameters on terminal velocity is discussed. Moreover, comparing the techniques, it is found that FEM is very efficient for solving governing equation and that has the best agreement with numerical results. The results are compared using Collocation Method (CM), Galerkin Method (GM) and Numerical Method. It is shown that GM gives accurate results. The terminal settling velocity has achieved earlier based on mass of the objects (i.e Aluminum, Copper and Lead). Numerical results obtained and indicated that the time of reaching the terminal velocity in a falling process is significantly increased with growing diameter of the object that validated with Numerical Method.