Block Nested Refinement and Numerical Estimation for Sudden Expansion Pipes in Various Step Angles

AUTHOR(S):

Christina G. Georgantopoulou

KEYWORDS

flow in pipes, sudden expansion, block nested grids, Navier-Stokes equations

ABSTRACT

The numerical simulation and estimation of flows inside channels is an essential tool for various applications due to the critical contribution in pipe control and inspection issues. In the present paper a simple, flexible and accurate numerical methodology is developed for the incompressible flows study inside sudden expansion pipes. Due to the nature of the physical domain the Cartesian grid approach is indicated for the domain discretization while it is combined with a block nested refinement technique in order to overcome the large number of computational cells are created due to the high aspect ratio of the specific problems. We develop testing of the refinement technique concerning the accuracy in various refinement factors as well as the step angle influence to the flow behavior and characteristics inside the pipe. The Navier-Stokes equations are solved using third accuracy upwind schemes in combination with the artificial compressibility technique for the pressure and the flux-vector splitting technique for the relating vectors. The flow behavior and variables are presented for various Reynolds numbers and step angle values in order to identify the optimum relation among expansion ratio, flow rate and separation zones. Corresponded results by the literature and by other numerical techniques are used for validation purposes presenting accepted convergence.

Cite this paper

Christina G. Georgantopoulou. (2016) Block Nested Refinement and Numerical Estimation for Sudden Expansion Pipes in Various Step Angles. International Journal of Mechanical Engineering, 1, 84-92