MODELLING METHODS FOR TAILING DAMS, COMPUTATIONAL FLUID DYNAMICS (CFD)

Transcription

1 1 MODELLING METHODS FOR TAILING DAMS, COMPUTATIONAL FLUID DYNAMICS (CFD) RESEM Workshop D.Sc.(Tech) Timo Kulju

2 2 INTRODUCTION CFD is based on solving the Navier-Stokes flow equations Fluid properties, such as density, viscosity, heat capacitance, together with operating and boundary conditions of the system determines the simulation results It can be used to model e.g. Newtonian and non-newtonian fluids, thermal energy transport, Multiphase flows including gas and liquid phases, as well as (small) solid particles For tailing dams it can be used to model e.g. paste flow dynamics, and Particle segregation from the main flow, i.e. sedimentation FACULTY OF TECHNOLOGY / Environmental and Chemical Engineering / Timo Kulju

3 3 CFD RESEARCH DONE IN DIFFERENT APPLICATIONS Oil industry Preventing sedimentation of the tube heat exhanger Steel industry Blast furnace modeling Modelling mixing of molten steel Laminar cooling of horizontal plates Heat recovery Thermal behaviour of heat exchangers Inorganic fouling on heat transfer surfaces FACULTY OF TECHNOLOGY / Environmental and Chemical Engineering / Timo Kulju

4 4 PREVENTING SEDIMENTATION IN TUBE HEAT EXHANGER Study the effect of flow modifiers in preventing the sedimentation Both physical and numerical CFD modelling utilized Validated CFD model applied to industrial setup Optimal flow odifier configurations obtained based on the CFD results FACULTY OF TECHNOLOGY / Environmental and Chemical Engineering / Timo Kulju

5 5 MULTIPHASE FLOWS STEEL INDUSTRY CAS-OB process is used in the secondary steel making to adjust the steel composition The vigorous Argon stirring has been modeled with CFD. Purpose of the detailed modelling is to Describe transport phenomena in the CAS- OB ladle. Wearing of the ladle Formation of the open-eye area Optimize the process operation FACULTY OF TECHNOLOGY / Environmental and Chemical Engineering / Timo Kulju

6 6 TAILING DYNAMICS Paste dynamics can be modeled with shear thinning Bingham model Utilizing multiphase modelling the paste spreading can be modeled FACULTY OF TECHNOLOGY / Environmental and Chemical Engineering / Timo Kulju

7 7 SEDIMENTATION Sedimentation in the dam can be done by By following the shear rates, the material deposits can be distinguished modelling several fluids simulataneously (Eulerian multiphase model), where paste grain size is included FACULTY OF TECHNOLOGY / Environmental and Chemical Engineering / Timo Kulju

8 8 HYDROLOGICAL MODELLING PEKKA ROSSI, UNIVERSITY OF OULU OULU, FINLAND 2 ND OF FEBRUARY 2016

9 DIFFERENT HYDROLOGICAL MODELLING ASPECTS 9 Groundwater modelling Integrated modelling (groundwatersurface water) Surface water flow models Chemical reaction models Water management

10 10 GROUNDWATER MODELLING Groundwater flow hard to measure, modelling a basic tool E.g. finite models as Modflow Groundwater flow from Rokua Esker aquifer to surrounding catchments a) Isotope 18 O/ 16 O ratio distribution, b) particle lines (lines), flow velocities (arrows) and c) tracer concentration in Kompsasuo wetland (Ronkanen & Kløve 2009 Water Res) Examples: treatment wetlands Aquifer modeling (e.g. new mining areas) Dams (3d-model cases) Recharge modelling

11 11 Groundwater modelling combined with surface water Understanding the role of groundwater e.g. in lakes or rivers Example of remote sensing as calibration method on lakes INTEGRATED MODELLING Thermal imagery data of colder shorelines (green) compared to modelled groundwater seepage (red) to lakes (Ala aho, P. et al J Hydrol.)

12 SURFACE WATER, CHEMICAL AND WATER MANAGEMENT MODELLING 12 Surface water flow models To understand pollutant transportation and mixing in river systems Clarify effect of wastewater discharging methods on mixing processes in river system Chemical purification reactions modelling Pollutant specifications PHREECQ, Hydrus Water management: water balance modelling of mines with stochastic models Goldsim