Validation of CFD Simulation with Scaled Physical Model of Tailings Dissipation Boxes

Transcription

1 Validation of CFD Simulation with Scaled Physical Model of Tailings Dissipation Boxes José Facusse Ingeniero Mecánico Daniel Manzo Ingeniero Hidráulico

2 PRESENTATION TOPICS Company Overview; Problem Description; Methodology; Results; Conclusions and Next Steps.

3 COMPANY OVERVIEW Energy Environment & Sustainability Minerals & Metals Process Infrastructure Program Management

4 COMPANY OVERVIEW What we do Infrastructure Energy Operations and Maintenance Pipeline Systems Port and Terminals Transportation Systems Minerals Processing Environment and Sustainability

5 COMPANY OVERVIEW Presence worldwide 30 OFFICES 19 COUNTRIES

6 PROBLEM DESCRIPTION Tailings Transportation System (TTS) Tailings impoundment facilities located 2200 m below the mine site. Launder 50 km long; about 5 km of high slope sections or rapids. Head Box Mine Site Final Box Tailings Impoundment 44 Dissipation Boxes

7 PROBLEM DESCRIPTION Dissipation Boxes Devices made of concrete, designed to dissipate the excess of kinetic energy of the flow at the discharge of a rapid.

8 PROBLEM DESCRIPTION Previous Simulations Simulation of dissipation boxes in real size.

9 METHODOLOGY First phase: CFD Simulation Scaling of the dissipation boxes (geometry and hydrodynamics); Generation of CAD models; CFD simulation (pre-processing, processing, post-processing); Results evaluation. Second phase: Laboratory Laboratory testing of scaled boxes; Comparison of results with CFD simulation.

10 METHODOLOGY Geometry Scaled dissipation boxes (1:12,5) Outlet Launder Outlet Volume Inlet rapid Receiving Chamber 12 parts Discharge Chamber Baffle

11 METHODOLOGY Meshing Elements type: Predominantly hexaedral. N of elements: About elements.

12 METHODOLOGY CFD Simulation ANSYS-CFX Multiphase flow simulation Euler-Euler model Air and tailings Turbulence model Shear Stress Transport (SST) Interphase transfer model Inhomogeneous model Particle model continuous phase (air) and disperse phase (tailings) Drag coefficient Schiller-Naumann

13 METHODOLOGY CFD Simulation ANSYS-CFX Model assumptions Isothermal domains; Channel and box walls and baffle are infinitely stiff with no structural bending; Self-aeration is not considered at the inlet rapid.

14 METHODOLOGY Physical model Equivalent fluid Water + glycerol (Newtonian; no particles) Velocity measurement Pitot tube (jet profile) ADV (velocity field) Pressure measurement Piezometers Level measurement Image processing

15 METHODOLOGY Comparison parameters CFD vs Physical comparison was based on the following parameters: Velocity profile of the submerged jet; Velocity field in the box; Fluid levels in the box; Pressure along the baffle in the jet impingement area.

16 RESULTS Physical models Laboratory facilities

17 RESULTS Physical models Laboratory facilities

18 RESULTS Physical models Dynamic pressure along the baffle

19 RESULTS Jet velocity field CFD vs Physical model submerged jet velocities Box 1 - Inlet slope 20% Box 2 - Inlet slope 40%

20 RESULTS Jet velocity field Good correlation between velocity distributions. First plane of measurements shows: Slightly higher maximum velocity magnitudes in physical models; Similar velocity profiles in both cases. Second plane of measurements shows: Similar velocity magnitudes in both cases; Velocity profile sharply decreases with depth in the lower part of the jet in the physical model.

21 RESULTS Jet velocity field Jet centerline tends to deflect upward in both cases Upward deflection is more pronounced in the physical models than in the CFD simulations.

22 RESULTS Fluid velocity field outside the jet region CFD vs Physical model fluid velocities Box 1 - Inlet slope 20% Vertical plane on the inlet rapid center Box 2 - Inlet slope 40% Horizontal plane at 4 cm

23 RESULTS Fluid velocity field outside the jet region Differences in the velocity fields are observed. In the central zone of the plane, both CFD and scale model results show velocities similar in magnitude but slightly different in direction. Significant differences are noted in the zones near the back wall and the bottom of the box.

24 RESULTS Fluid level CFD vs Physical model fluid levels (lateral view) Box 1 - Inlet slope 20% Box 2 - Inlet slope 40%

25 RESULTS Fluid level Results are qualitatively consistent with each other. Levels are higher in physical models than CFD. Overelevation effect before the baffle is higher in physical model.

26 RESULTS Pressure along the baffle CFD vs Physical model pressure along a vertical plane in the baffle Box 1 - Inlet slope 20% Box 2 - Inlet slope 40%

27 RESULTS Pressure along the baffle Pressure in the physical model are higher than in the CFD. The maximum dynamic pressure is obtained at a higher location in the physical model, which is consistent with the differences in the submerged jet trajectory.

28 CONCLUSIONS The results show coherence between CFD simulations and laboratory scaled models results. Satisfactory results were obtained in terms of overall hydraulic behavior and jet dissipation. However, some discrepancies in velocity distribution and levels inside the boxes were found. The physical-cfd simulation comparison provided data for calibration of the CFD simulation. At this point it is concluded that the two-phase simulation is still necessary to validate the results.

29 NEXT STEPS A more accurate CFD simulation should be obtained in the future, possibly dispensing with the physical modeling phase. Physical model results to be used to improve CFD simulation.

30 Muchas gracias.

31 Validación de Simulación CFD con Modelo Físico a Escala de Cajones Disipadores de Relaves José Facusse Ingeniero Mecánico Daniel Manzo Ingeniero Hidráulico