Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Study of the influence of the film height on near interface turbulent structure in gas-liquid stratified via DNS
Submission Author:
Victor Wagner Freire de Azevedo , RN
Co-Authors:
Victor Wagner Freire de Azevedo, Emilio Paladino, Fabian Denner
Presenter: Victor Wagner Freire de Azevedo
doi://10.26678/ABCM.COBEM2023.COB2023-1073
Abstract
Stratified gas-liquid flows are present in several applications in nature and industrial processes. In such flows, the near-interface turbulence structure is important as is the region responsible for mass, momentum, and energy transfer between the phases. In flow with high Reynolds numbers, the turbulence phenomena in this region governs friction pressure loss and heat and mass diffusion, as well as it affects the onset of interfacial wave formation and, eventually, pattern transition. Despite the availability of turbulence models with different levels of detail and assumptions, the direct numerical simulation is still a useful tool for fundamental studies in many flows. Furthermore, for the case of turbulent flows in the presence of fluid-fluid interfaces, typical turbulence models are based on modifications of those developed for single phase flow and normally application based with adjustable parameters. Some previous works studied the turbulence in the near-interface region in stratified flows but did not consider the influence of the wall in near-interface turbulence statistics, as the developed models typically include only the interface region and not the actual wall-bounded stratified channel flow. In the present work, considering a computational domain bounded by no-slip walls, we show that near-interface turbulence structure is affected by the presence of walls by performing DNS of stratified channel flow considering different film heights. The model is developed in a second order finite volume framework for the flow in a wall-bounded gas-liquid stratified flow with different film heights considering the volume-of-fluid model for the advection of volume fraction. The results show increasing in interfacial friction factor and decreasing in turbulence production for the smaller film height with relation to the bigger film height, which leads to conclusion that not only the interface deformation but also the distance of the interface to the wall affects the turbulence structure in the near-interface region.
Keywords
Stratified flow, Direct Numerical Simulation (DNS);, near-interface turbulence
