Two-fluid modeling of gas-solid flows: a sub-grid analysis applying forcing function method and application of dynamical adjustment to large scale simulations

• Grant number: 14/11359-2
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: March 01, 2015
• End date: February 29, 2016
• Field of knowledge: Engineering - Chemical Engineering - Chemical Process Industries
• Principal Investigator: Paulo Seleghim Júnior
• Grantee: Christian Lea Coelho da Costa Milioli
• Supervisor: Sankaran Sundaresan
• Host Institution: Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Institution abroad: Princeton University, United States
• Associated to the scholarship: 13/03745-7 - Sug-grid closures for gas-solid flows modeling, BP.PD

Abstract

The present proposal of abroad research stage integrates the context of the current post-doctoral work, project FAPESP 2013/03745-7. Professor Sankaran Sundaresan is a collaborator to this project and the abroad stage is proposed to be developed at Princeton University under his supervision. The project FAPESP 2013/03745-7 was implemented in july 2013 and its major goals are the development of new sub-grid correlations for gas-solid flows applying the procedure of forcing function and the implementation of dynamical adjustment in large scale simulations. Until now, it was accomplished an extensive review of the pertinent literature and the implementation of preliminary tests of the forcing procedure applied to highly resolved simulations of gas-solid flows. The results of the performed tests applying two different mathematical shapes of the forcing procedure proved promising allowing the values of the scalar shear rates of both the phases to be changed, as intended, without introducing any pattern or changing the flow topology. Verified the successful implementation of forcing on gas-solid flows, the current stage of the work turns towards the systematic verification of the flow response to the disturbances imposed by forcing in different ranges of frequency. This procedure, usual in sub-grid studies of monophasic turbulence, will allow to investigate the issue of the lack of scale separation in gas-solid flows, besides introducing in the simulations different values of scalar shear rate to verify the response of filtered viscous parameters of both phases. The stage of testing will continue over the next months in order to rigorously establish the way through which the forcing disturbances must be imposed over the simulations, thereby establishing a methodology. In Princeton it is intended to accomplish an extended stage of computational experimentation applying forcing followed by result analysis looking for the enhancement of the viscous models proposed by Milioli et al., 2013. The other topic, also a subject of the current post-doctoral project, is the dynamical adjustment, to be applied in large scale simulations. At this moment, the dynamic adjustment issue is in process of literature review and establishment of preliminary implementation tests, which should be extended over the next months. It is expected to continue these developments through the staying in Princeton. The current post-doctoral project in development in Brazil represents a continuity of the research work accomplished by this researcher in Princeton between october/2011 and december/2012 (FAPESP process 2011/11278-4). The work developed in Princeton in 2011-2012 was highly productive, resulting in two publications in scientific journals and seven publications in international scientific events. The researches that were accomplished in Princeton produced a real contribution to the state of the art with the development of new sub-grid models that were recently implemented in the open code MFIX of the USA Department of Energy (release MFIX2013-2, National Energy Technology Laboratory, U. S. Department of Energy, https://mfix.netl.doe.gov/). It is evaluated that the achieved success in 2011-2012 was a direct consequence of the work conditions offered by Princeton University and by Professor Sundaresan's research group. The rhythm of the work was intense in view of the constant interactions with the local high level scientists in the concerning research area, and in view of the wide availability of infrastructure, high level computational resources and highly efficient technical support. Such conditions do not exist at EESC-USP, where the current post-doctoral project is being developed. For this new stage of research proposed to be developed in Princeton results similar to those obtained in 2011-2012 are expected, with new contributions to the state of the art through the proposition of even more realistic sub-grid models. (AU)