Numerical Simulation of Flow Regimes and Heat Transfer Interactions in Complex Geometries

Abstract

The recent advances in numerical methods and the vast development of computers had directed the designers to better development and modifications to airflow pattern and heat transfer in complex geometries such as boiler furnaces, combustion chambers, aluminum reductions cells and air conditioned operating theatres and plant rooms. The Present work reviews the status quo of the modeling techniques and presents a technical evaluation of the historical development of mathematical modeling from the early seventies of the twentieth century till now. The paper fosters mathematical modeling techniques to primarily predict what happens in threedimensional complex geometries and presents a summary of its status quo. Applications include, among others, combustion chambers, aero engines in terms of flow regimes and interactions .It also includes predictions of flow and heat transfer in Aluminum reduction pots where the pot is full with the molten metal and electrolyte in the anodes-cathode void under magnetic field and forces. The flow in air-conditioned operating theatres is also addressed in this paper among fire spreads in rooms and smoke management.The governing equations of mass, momentum, species and energy, expressed in a general finite difference form, are solved with the aid of various Algorithms that are critically analyzed for practical engineering applications. Examples are shown for computations using SIMPLE and SIMPLEC algorithms. The sample predictions results shown here are obtained in this work with the aid of the three-dimensional program; applied to three-dimensional complex geometries. The numerical grid comprises, typically, 100x100x50-grid mesh of total 500000-grid nodes; the numerical residual in the governing equations were typically less than 0.001 %.The obtained results include velocity components, turbulence intensities, temperatures and wall heat fluxes. Flow regimes and heat transfer were found to be strongly dependent on turbulent shear, mixing, blockages, wall conditions and inlet conditions. Examples of large industrial furnaces, reduction cells and operating theatres are shown and are in good agreement with experiments found in the open literature .One may conclude that flow patterns, turbulence and heat transfer in complex geometries are strongly affected by the inlet and boundary conditions; both micro and macro mixing levels are influential. The present modeling capabilities can adequately predict the local flow pattern and turbulence kinetic energy levels in Complex geometries

Air flow regimes and IAQ modeling in air conditioned spaces

“…The computational number of iterative steps is selected according space cell (spatial difference) to yield converged solutions [9]. The validity of the present computational technique was assessed previously in the open literature, for example in references [8][9][10][11][12][13][14][15][16][17]. where reference should be made for more detailed readings.…”