Numerical Modeling For Primary Atomization Of Liquid Jets

Author : Vincent Henri Marie Le Chenadec
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (89 download)

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Download or read book A Stable and Conservative Framework for Detailed Numerical Simulation of Primary Atomization written by Vincent Henri Marie Le Chenadec and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Energy conversion devices often rely on the combustion of high energy-density liquid fuel to meet weight and volume restrictions. The efficiency of the conversion and the emission of harmful pollutants depend directly on the mixing of the fuel and oxidizer, which itself results from a cascade of mechanisms initiated by the atomization of a coherent liquid stream. Despite existing investigations, the effects of nozzle design, surface tension, turbulence, and cavitation on atomizer performance are still poorly understood. The challenges found in experimental studies caused by the multi-scale and multi-physics aspects of such flows have motivated the development of numerical strategies to simulate the atomization process. In the direct numerical simulation approach considered in this work, the physics of the flow are all solved for directly. In the presence of complex topologies, the underlying equations are stiff, and, therefore, the development and improvement of numerical methods has been an area of active research. Among algorithms that have emerged, sharp interface methods including Volume-of-Fluid and Level Set have been shown to give reasonable performance. Applications of these methods to study primary atomization of turbulent jets have been documented, but the rare convergence studies available show strong grid dependence, suggesting the need for further developments. The present work focuses on two novel developments: an unsplit Volume-of-Fluid interface capturing algorithm designed to improve conservation on arbitrary grids, and a robust flow solver for incompressible Navier-Stokes equations in two-phase flows involving large density ratios. The resulting approach is shown to be stable and second order accurate. The framework is then assessed in a set of validation cases. In particular, the effect of mesh resolution is studied, and the ability of the method to accurately retain under-resolved structures is shown. Finally, computations of a large scale atomizer for varying operating conditions are presented. The excellent computational efficiency of the algorithm motivates the use of such a framework for simulating industrially relevant configurations.