Estudo da convecção forçada, natural e mista em escoamentos laminares e turbulentos utilizando o método de volumes finitos

Abstract

A theoretical study of laminar and turbulent flow with heat transfer by forced, natural, and mixed convections is performed in this work using the finite volume method to approximate solutions to some different domains and, therefore, a few computational codes are developed in order to do that. When forced convection problems are concerned, the following situations are analyzed: laminar and turbulent convection in straight and U-shaped channels, both with and without restrictions. As for natural convection problems, the ones considered are: turbulent flow in rectangular cavities with the left, right, and horizontal walls being heated, cooled, and isolated, respectively. Some other geometries involving natural convection are studied such as triangular cavities submitted to many boundary conditions and a rectangular cavity with an internal heated cylinder and an upper surface with convection to the environment. In addition to the previous cases, there are still the mixed convection ones that are: square cavities with an upper inlet opening on the left vertical surface and a lower outlet opening on the right wall. These vertical surfaces with the openings are isothermal whereas the horizontal ones are adiabatic. The conservation equations are discretized through the finite volume method. The turbulence models which are implemented are: k-ω model and the sub-grid model (Smagorinsky model, Smagorinsky model with buoyancy terms, vorticity transfer theory model, and the sub-grid and velocity structure function model). Local and average Nusselt numbers are calculated for all the cases mentioned previously.