Numerical investigation of forced convection of non Newtonian fluids across a square cylinder

Daniel Dall'Onder dos Santos¹; Luís Gustavo Souza Machado¹

¹ Federal University of Uberlândia

doi:10.20906/CPS/COB-2015-2222

Resumo

Several fluids found in industrial processes exhibit non Newtonian behavior. In some applications, these materials are subjected to heat transfer by forced convection. The main goal of this work is to perform numerical simulations of non-isothermal two-dimensional steady state laminar flows of non Newtonian fluids through a planar channel obstructed by a square cylinder. The mechanical model is defined by the mass, momentum and energy balance equations coupled to non Newtonian constitutive models for pseudoplastic and viscoplastic fluids. This modeling is approximated by a stabilized multi-field Galerkin finite element methodology, having as primal variables the extra-stress, velocity, pressure and temperature fields. In this way, the compatibility conditions between the extra-stress-velocity and pressure-velocity finite element subspaces are violated, allowing the use of equal-order finite element interpolations. In the performed numerical simulations, the fluid rheological parameters, namely the jump number, the power-law coefficient, the non-dimensional flow rate and the non-dimensional density are varied in order to evaluate their influence on the heat transfer through the geometry.

Palavras-chave: forced convection heat transfer; multi-field mechanical modeling; Galerkin least-squares; non Newtonian fluids