Direct Numerical Simulation of Multiphase Flows with Unstable Interfaces

7th European Thermal-Sciences Conference

Schillaci, Eugenio^1 ; Lehmkuhl, Oriol^1 ; Antepara, Oscar^1 ; Oliva, Assensi^1

Heat and Mass Transfer Technological Centre (CTTC), Universitat Politcnica de Catalunya (UPC), ESEIAAT, Carrer de Colom 11, Terrassa (Barcelona)

08222, Spain^1

关键词: Adaptive mesh refinement;    Interface capturing;    Interface phenomena;    Kelvin- helmholtz instabilities;    Rayleigh instability;    Surface instability;    Turbulent vortices;    Unstable interfaces;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/745/3/032114/pdf
DOI  :  10.1088/1742-6596/745/3/032114

来源: IOP

【 摘 要 】

This paper presents a numerical model that intends to simulate efficiently the surface instability that arise in multiphase flows, typically liquid-gas, both for laminar or turbulent regimes. The model is developed on the in-house computing platform TermoFluids, and operates the finite-volume, direct numerical simulation (DNS) of multiphase flows by means of a conservative level-set method for the interface-capturing. The mesh size is optimized by means of an adaptive mesh refinement (AMR) strategy, that allows the dynamic re-concentration of the mesh in the vicinity of the interfaces between fluids, in order to correctly represent the diverse structures (as ligaments and droplets) that may rise from unstable phenomena. In addition, special attention is given to the discretization of the various terms of the momentum equations, to ensure stability of the flow and correct representation of turbulent vortices. As shown, the method is capable of truthfully simulate the interface phenomena as the Kelvin-Helmholtz instability and the Plateau-Rayleigh instability, both in the case of 2-D and 3-D configurations. Therefore it is suitable for the simulation of complex phenomena such as simulation of air-blast atomization, with several important application in the field of automotive and aerospace engines. A prove is given by our preliminary study of the 3-D coaxial liquid-gas jet.