STSMs approved in the 1st Grant Period
STSM Coordinator: Dariusz Asendrych
E-mail: darek@imc.pcz.czest.pl
Host: Dariusz Asendrych, Czestochowa University of Technology, PL
Period: 15/01/2012 - 15/03/2012 (COMPLETED! Download the final report)
Work Plan Summary: The objective of the present STSM grant proposal is to simulate the pipe flow of pulp suspensions using the CFD commercial software ANSYS FLUENT and to validate the simulations by comparing the numerical results and experimental results for the pressure drop. The licensed access to Ansys Fluent (unavailable at Coimbra University) will be provided by Czestochowa University of Technology, also in future computations after STS mission is completed. The work will be divided in two stages. The first step will be to become proficient in the use of ANSYS FLUENT, in particular the STSM candidate will acquire knowledge about:
• geometry and mesh generation in Gambit (Fluent`s preprocessor),
• setting up the CFD case in Fluent,
• execution of calculations, convergence monitoring, post-processing,
• preparation and use of UDFs (user-defined functions) for model development e.g. implementation of rheological material properties, adding source terms to equations,
• use of Linux platform and multi-processor machines for parallel computing.
The second step will be dedicated to simulate an experimental case for the turbulent pipe flow of pulp suspensions with a pseudo-homogeneous model. The dynamic viscosity will be introduced in the model as a function of velocity or a function of shear rate. It is foreseen to conduct the calculations for different fibre types, varying consistencies and bulk velocities. The numerical results will be compared with experimental results for the pressure drop obtained in a pilot rig and with the draft results obtained with the use of COMSOL Multiphysics software.
Host: Juha Salmela, VTT technical Research Center of Finland, FI
Period: 22/01/2012 - 18/02/2012 (COMPLETED! Download the final report)
Work Plan Summary: The objective of the STSM mission is to perform series of experiments devoted to the measurements of the flow file including detailed velocity distribution as well as the motion and deformation of single fibres. The experiments will be conducted with the use of specialised measuring equipment including ultra sound velocimetry, optical coherence tomography and particle image velocimetry. It is planned to perform experimental trials for different fibre types, consistencies and flow conditions. Hosting intuition enables possibility to take into consideration different types of fibres (having different material properties and dimensions) including natural fibres like Birch or Pine ass well as synthetic ones. The results of this experiments will be used for the validation of the numerical model of fibre suspension behaviour being developed by STMS applicant in the frame of PhD project. It should be noted that the above mentioned experimental work can not be done in applicant home institution. Hosting Institution will provide the necessary assistance and guidance in realization of the proposed scientific mission.
Host: Fredrik Lundell, KTH - Royal Institute of Technology, SE
Period: 06/02/2012 - 06/05/2012 (COMPLETED! Download the final report)
Work Plan Summary: Objectives of work are to Combine PIV and fibre orientation measurements. On the water table at Linne FLOW Centre, KTH Mechanics, a suspension film of water and fiber is flowing down an inclined plate driven by gravity. This is a good experimental model of one-half of channel flows often used in direct numerical simulation studies. Measurements will be carried out by capturing images of fibres and PIV tracer particles in planes parallell to the wall. The planes are defined by a illumination with a laser sheet and images will be acquired both with and without fibres. The images will be analyzed in two ways: PIV will be used to determine the local, instantaenous flow velocities, and a steerable filter will be used to determine the fiber orientation and Position of the fibres in the images. The first purpose is to provide information on local structures of flow, fibre positions and fibre orientations, albeit not simultaneous. When this are achieved, efforts will be made to extract flow data from the images with both tracers and fibres by eliminating the fibres from the images once their positions and orientations has been determined.
Host: Cristian Marchioli, CISM and University of Udine, IT
Period: 24/06/2012 - 30/06/2012 (COMPLETED! Download the final report)
Work Plan Summary: During the stay, we would like to analyse recent results of direct numerical simulation (DNS) and Large eddy simulation (LES) of turbulent flows in presence of particles and micro-fibers. In particular, it would be instructive to study and understand the statistical and geometrical nature of the error committed in the large eddy simulation in order to devise some original and novel approaches for the fiber suspension flow modelling. With this analysis, on one hand we would like to measure on a quantitative ground the statistics of that error also with respect to different physical parameters at play, notably form and dimensions of fibers. On the other hand, we would like to figure out which geometrical coherent structures are mainly relevant for the dynamics of fibers and if this dynamics change drastically with fiber shape. Hence we should analyse present results and on this basis schedule a series of quantitative studies. It would be also interesting to try to write down a first subgrid model for LES. Even though a precise comprehension of fiber suspension flow modelling is far from being acquired, we expect a somewhat analogy with simple point-particle case, at least in some limit. Therefore, the model should be stochastic and the basis for a suitable one would be a Langevin equation. This conjecture should be clearly confirmed via the analysis of simulations. Definition of the different terms in that model remains the challenging issue.
Host: Cristian Marchioli, CISM and University of Udine, IT
Period: 18/06/2012 - 30/06/2012 (COMPLETED! Download the final report)
Work Plan Summary: The applicant will apply and extend the development of pdf methods based on simple Stokes drag for spherical particles to non spherical particles of variable geometry and shape factor. The objective will be to develop an appropriate PDF eqn. and use this to obtain the mass momentum and kinetic stress equations together with similar equations for the angular momentum and rotational energy. The focus to begin with will be on dispersion in homogeneous turbulence and simple shear flows as has been dome for spherical particles. Simulation will be carried out to validate some of the results in KS random flow fields and in DNS. In particular:
1. Formulate kinetic equations for non spherical particles to take advantage of drag lift and rotations
2. Apply suitable closure models either based on LHDI or Furutsu Novikov theorem
3. Derive the appropriate continuum equations and consider the predicted forms for the kinetic stress diffusion coefficient tensor in homogenous isotropic turbulence as well as simple shear flow
4. Validate the results against simulation using Kinematic simulation and DNS
E-mail: darek@imc.pcz.czest.pl
| Beneficiary: Ms Carla Cotas, University of Coimbra, PT |  |
Host: Dariusz Asendrych, Czestochowa University of Technology, PL
Period: 15/01/2012 - 15/03/2012 (COMPLETED! Download the final report)
Work Plan Summary: The objective of the present STSM grant proposal is to simulate the pipe flow of pulp suspensions using the CFD commercial software ANSYS FLUENT and to validate the simulations by comparing the numerical results and experimental results for the pressure drop. The licensed access to Ansys Fluent (unavailable at Coimbra University) will be provided by Czestochowa University of Technology, also in future computations after STS mission is completed. The work will be divided in two stages. The first step will be to become proficient in the use of ANSYS FLUENT, in particular the STSM candidate will acquire knowledge about:
• geometry and mesh generation in Gambit (Fluent`s preprocessor),
• setting up the CFD case in Fluent,
• execution of calculations, convergence monitoring, post-processing,
• preparation and use of UDFs (user-defined functions) for model development e.g. implementation of rheological material properties, adding source terms to equations,
• use of Linux platform and multi-processor machines for parallel computing.
The second step will be dedicated to simulate an experimental case for the turbulent pipe flow of pulp suspensions with a pseudo-homogeneous model. The dynamic viscosity will be introduced in the model as a function of velocity or a function of shear rate. It is foreseen to conduct the calculations for different fibre types, varying consistencies and bulk velocities. The numerical results will be compared with experimental results for the pressure drop obtained in a pilot rig and with the draft results obtained with the use of COMSOL Multiphysics software.
| Beneficiary: Mr Gregorz Kondora, Czestochowa University of Technology, PL | |
Host: Juha Salmela, VTT technical Research Center of Finland, FI
Period: 22/01/2012 - 18/02/2012 (COMPLETED! Download the final report)
Work Plan Summary: The objective of the STSM mission is to perform series of experiments devoted to the measurements of the flow file including detailed velocity distribution as well as the motion and deformation of single fibres. The experiments will be conducted with the use of specialised measuring equipment including ultra sound velocimetry, optical coherence tomography and particle image velocimetry. It is planned to perform experimental trials for different fibre types, consistencies and flow conditions. Hosting intuition enables possibility to take into consideration different types of fibres (having different material properties and dimensions) including natural fibres like Birch or Pine ass well as synthetic ones. The results of this experiments will be used for the validation of the numerical model of fibre suspension behaviour being developed by STMS applicant in the frame of PhD project. It should be noted that the above mentioned experimental work can not be done in applicant home institution. Hosting Institution will provide the necessary assistance and guidance in realization of the proposed scientific mission.
| Beneficiary: Mr Afshin Abbasi Hoseini, Trondheim University of Technology, NO | |
Host: Fredrik Lundell, KTH - Royal Institute of Technology, SE
Period: 06/02/2012 - 06/05/2012 (COMPLETED! Download the final report)
Work Plan Summary: Objectives of work are to Combine PIV and fibre orientation measurements. On the water table at Linne FLOW Centre, KTH Mechanics, a suspension film of water and fiber is flowing down an inclined plate driven by gravity. This is a good experimental model of one-half of channel flows often used in direct numerical simulation studies. Measurements will be carried out by capturing images of fibres and PIV tracer particles in planes parallell to the wall. The planes are defined by a illumination with a laser sheet and images will be acquired both with and without fibres. The images will be analyzed in two ways: PIV will be used to determine the local, instantaenous flow velocities, and a steerable filter will be used to determine the fiber orientation and Position of the fibres in the images. The first purpose is to provide information on local structures of flow, fibre positions and fibre orientations, albeit not simultaneous. When this are achieved, efforts will be made to extract flow data from the images with both tracers and fibres by eliminating the fibres from the images once their positions and orientations has been determined.
| Beneficiary: Dr Sergio Chibbaro, Institut D'Alembert Universite' Paris 6, FR | |
Host: Cristian Marchioli, CISM and University of Udine, IT
Period: 24/06/2012 - 30/06/2012 (COMPLETED! Download the final report)
Work Plan Summary: During the stay, we would like to analyse recent results of direct numerical simulation (DNS) and Large eddy simulation (LES) of turbulent flows in presence of particles and micro-fibers. In particular, it would be instructive to study and understand the statistical and geometrical nature of the error committed in the large eddy simulation in order to devise some original and novel approaches for the fiber suspension flow modelling. With this analysis, on one hand we would like to measure on a quantitative ground the statistics of that error also with respect to different physical parameters at play, notably form and dimensions of fibers. On the other hand, we would like to figure out which geometrical coherent structures are mainly relevant for the dynamics of fibers and if this dynamics change drastically with fiber shape. Hence we should analyse present results and on this basis schedule a series of quantitative studies. It would be also interesting to try to write down a first subgrid model for LES. Even though a precise comprehension of fiber suspension flow modelling is far from being acquired, we expect a somewhat analogy with simple point-particle case, at least in some limit. Therefore, the model should be stochastic and the basis for a suitable one would be a Langevin equation. This conjecture should be clearly confirmed via the analysis of simulations. Definition of the different terms in that model remains the challenging issue.
| Beneficiary: Prof Mike Reeks, University of Newcastle upon Tyne, UK | |
Host: Cristian Marchioli, CISM and University of Udine, IT
Period: 18/06/2012 - 30/06/2012 (COMPLETED! Download the final report)
Work Plan Summary: The applicant will apply and extend the development of pdf methods based on simple Stokes drag for spherical particles to non spherical particles of variable geometry and shape factor. The objective will be to develop an appropriate PDF eqn. and use this to obtain the mass momentum and kinetic stress equations together with similar equations for the angular momentum and rotational energy. The focus to begin with will be on dispersion in homogeneous turbulence and simple shear flows as has been dome for spherical particles. Simulation will be carried out to validate some of the results in KS random flow fields and in DNS. In particular:
1. Formulate kinetic equations for non spherical particles to take advantage of drag lift and rotations
2. Apply suitable closure models either based on LHDI or Furutsu Novikov theorem
3. Derive the appropriate continuum equations and consider the predicted forms for the kinetic stress diffusion coefficient tensor in homogenous isotropic turbulence as well as simple shear flow
4. Validate the results against simulation using Kinematic simulation and DNS