CFD Flocculation Tank Simulation
Overview
Little information is available about the fluid behavior within the flocculation. The flow is turbulent and involves separation, reattachment, and high shear. Our team examines CFD simulation to predict velocity gradients, pressure losses and energy dissipation rate in the flocculation tank. By varying geometric configurations, and analyzing the resulting energy dissipation rates, the design of the flocculation tank can be optimized. Below is the energy dissipation rate for the a five baffle flocculator with a height to baffle spacing ratio of 2, and a clearance height to baffle spacing ratio of 1.
CFD Flocculation Tank Simulation goals and meeting minutes.
Research
Fall 2008 Research Paper
CFD Analysis of Flocculation Tank and Design Recommendation
Fall 2008 Research Paper Sub-TopicsTurbulence model validation
Validate which turbulence model to use. K-e realizable or K-w SST
Examines the back-step example to determine the type of turbulence model to use in FLUENT.Gtheta computationGtheta computationGtheta computation
Calculate Gθ and compare with the theoretical data
Determines the Gθ value for various flocculation height (fh) to baffle spacing (bs) ratios using a UDF in FLUENT.Reynolds effects on energy dissipation rateReynolds effects on energy dissipation rate
Analyze how energy dissipation rate is affected by Reynolds number
Examines the affect of varying the velocity inlet from .1 m/s which corresponds to a Re=10,000 to 1 m/s (Re=100,000) and .01 m/s (Re=1,000).Investigation of Turbulence Boundary ConditionInvestigation of Turbulence Boundary Condition
Investigation of Turbulence Boundary Condition
Examines the affect of varying the turbulent inlet length scale for the optimal geometry.Uniform Energy Dissipation Rate Approach in Determining Optimal GeometryUniform Energy Dissipation Rate Approach in Determining Optimal Geometry
Uniform Energy Dissipation Rate Approach in Determining Optimal Geometry
Determines the optimal geometry for the flocculation tank by varying the fh/bs, and ch/bs ratios.Performance Parameter Approach in Determining Optimal GeometryPerformance Parameter Approach in Determining Optimal Geometry
Performance Parameter Approach in Determining Optimal Geometry
Determines the optimal fh/bs ratio for the flocculation tank height by comparing performance parameters which quantify flocculation collision potential
Spring 2008 Research Topics
- Model and validate a simple 180 degree turn over two baffles:*
- Create fully second order accurate model
- Perform mesh sensitivity analysis (using coarse, medium and fine meshes)
- Model the baffles using alternate Turbulence models (K-e Standard, K-e Realizable, K-w)
- Analyze the effects of changing the baffle clearance height
- Understand and analyze the relationship between Strain Rate, Energy Dissipation and Kinematic Viscosity
- Create a flexible mesh that uses parametrization to easily change geometry dimensions
- Analyze the effect of the Reynolds Number on the results
- Analyze the sensitivity of the model to convergence residuals
- Model flocculation tank and compare Simulation to Experimental results.*
Spring 2008 Documentations:
Other Information
- Flocculator with multiple baffles
- Automation of Mesh Creation
- Nondimensional Analysis
- Johannes Haarhoff and Jeremia J. van der Walt , J Water SRT - Aqua 50 (2001) 149-160 - - Towards optimal design parameters for around-the-end hydraulic flocculators.
- Relation of Shear Stresses to Floc Strength
- CFD Flocculation Tank Simulation Research
- CFD Fall 2008 Midtem Report
- CFD Spring 2008 Midterm Teach-in Presentation
- CFD Spring 2008 Final Report
- CFD Fall 2008 Midterm Teach-in Presentation
- CFD Fall 2008 Midtem Report
- CFD Fall 2008 Final Report
- CFD Flocculation Tank Next Semester Quiz