Local Refinement Approach For Incompressible Developing Flows Inside Pipes
Pipeline’s flow simulation and estimation is a critical topic with high industrial interest. However in order to produce a flexible, simple and accurate enough numerical scheme high aspect ratios as well as local non-Cartesian pipes bound have to be treated. In order to overcome these difficulties a local mesh refinement technique is developed and applied in flows inside pipes producing approximated outer bounds wherever is necessary simultaneously. The numerical scheme is applied for incompressible, viscous, laminar steady and unsteady flows giving priority to the boundary conditions application according to the position of outer cells. Navier-Stokes equations are solved using upwind schemes, cell centered approach and finite volume methodology. Numerical results for the flow variables values and distribution are presented for straight pipe, pipe with step in various. According to each specific physical domain, a local refinement grid approach is developed providing accurate results and reducing the computational memory and time simultaneously. Validation of the results has been presented with satisfied convergence with corresponded results from the literature as well as from the commercial flow software package ANSYS. Emphasis is given to recirculation zones localization as well as to pressure drop regions providing by this way useful data to the related industries. The methodology is simple and accurate enough in order to predict industrial flows inside pipes as crude oil, gas or air internal flows.
Key-words- Block-structured grids, Navier Stokes equations, incompressible flows, channel flow, flow in pipes.