Chromatography Column Scale-Up
One chromatography column developer was having challenges scaling up an existing design to a larger version. Our team worked with the manufacturer using Computational Fluid Dynamics (CFD) to understand the reasons for the reduced performance. CFD modeling was used to pinpoint reduced performance when moving from existing, small scale units to upscaled columns.
In the work we peformed, we were able to validate a CFD model and calibrate porous dispersion coefficients for the existing column. Moving to the larger column, however, initial results could not be reproduced with CFD. It was found that for the upscaled column, the synthetic textile mesh that forms the boundary between the distributor and the packed bed had deformed under the packing pressure of the column, such that the distributor was pinched off, and the outer radius of the packed bed was starved of flow. Computing the deformation of this mesh around the radial rib supports—and including this effect in the CFD simulations—showed that the upscale experimental results could be reproduced. The solution was verified in subsequent experiments.
Through a recommended design change, we were able to show that the high level of performance typical of the existing column could be reproduced in the upscaled column. The improved design is also able to be packed more consistently, and operates at a lower pressure loss than the original.
Capability
Applied Data & TechnologyServices
Process EngineeringRelated Projects
In order to meet screen velocity requirements of the Clean Water Act 316 b rule, American Electric Power has investigated the possibility of replacing the Clifty Creek Power Plant traveling water screens with an array of cylindrical wedgewire screens in the cooling water intake forebay. The site on the Ohio River experiences significant siltation, and there were concerns about associated vulnerability of the wedgewire screens.
Alden performed flow modeling to evaluate this possibility, and provide possible solutions. The model scope included river flow both upstream and downstream of the intake structure and flow within the intake structure. To model the geometric details of the system accurately, a field survey conducted by Alden was performed prior to the flow modeling efforts. The flow study included 2D and 3D numeric modeling, as well as scale physical modeling.
}', 13='{type=image, value=Image{width=2000,height=683,url='https://20952198.fs1.hubspotusercontent-na1.net/hubfs/20952198/PROJECTS/ALDEN/Clifty-Creek/Clifty-Creek-Site-Visit.jpg',altText=''}}', 14='{type=string, value=Field survey conducted prior to model testing}', 25='{type=number, value=0}', 27='{type=number, value=1}', 28='{type=number, value=0}', 29='{type=number, value=30}'}
Applied Data & Technology | Civil Infrastructure
Clifty Creek Power Plant Intake Modification
investigation of the hydraulic, thermal, and sediment dynamics within a cooling water intake forebay on the Ohio River, including both 3D numeric and physical modeling
As part of project/dam surrender and removal efforts at the Saccarappa Hydroelectric Project (Saccarappa), Alden provided S. D. Warren Company d/b/a Sappi North America (Sappi) with the final design and fish passage analysis for nature-like fishways in the upper channels at Saccarappa Falls. The final design involves reshaping the existing bedrock channel into a form that is more conducive to fish passage while mimicking the morphology of a natural bedrock channel. Alden provided agency consultation while developing the design and will ultimately provide construction support. The proposed design complements a proposed double Denil fishway over the lower portion Saccarappa Falls designed in partnership with Acheron Engineering.
Alden conducted a site visit and reviewed existing geotechnical, hydrologic, site constraints, and other site data prior to developing the final design for the nature-like fishways. The final design was achieved by way of iteration between a 3D CAD representation of the proposed bathymetric surface and a 3D computational fluid dynamics (CFD) model. Expected small-scale roughness of the channel bed was incorporated into the CAD surface through a novel texturizing technique based on a high resolution laser scan of the existing bedrock surface. The CFD model was used to simulate proposed conditions at four discrete design flow rates. Hydraulic data output by the CFD model (e.g., depth and velocity) informed subsequent improvements of the proposed surface in CAD. Sappi and agency review and feedback was provided at 30%, 60%, 90%, and final drafts of the design. Fish passage effectiveness of the final design was analyzed by Alden biologists and engineers using USFWS’s SMath models developed for assessing velocity impediments by estimating fatigue, survivorship, and work. Alden also provided engineering consultation and inspections to support project construction.
}', 13='{type=image, value=Image{width=2000,height=905,url='https://www.verdantas.com/hubfs/PROJECTS/Saccarappa-Falls-Nature-Like-Fishway-Design.jpg',altText=''}}', 14='{type=string, value=3D CFD modeling was used to aid in the design and evaluation of the nature-like fishway}', 15='{type=image, value=Image{width=1623,height=826,url='https://www.verdantas.com/hubfs/assets/news/saccarappa-dam-removal-iso-rendering.jpg',altText=''}}', 16='{type=string, value=CFD Modeling helped guide the engineering of two channels in the upper falls and the Denil ladder at the lower falls.}', 17='{type=image, value=Image{width=1500,height=750,url='https://www.verdantas.com/hubfs/IMAGES/Alden/Imported_Blog_Media/CFD-Nature-Like-Fishway.jpg',altText=''}}', 18='{type=string, value=CFD-based design provided an innovative approach to create the Nature-Like Fishway}', 25='{type=number, value=0}', 27='{type=number, value=1}', 28='{type=number, value=1633352533000}', 29='{type=number, value=350}'}
Applied Data & Technology | Civil Infrastructure | Natural Resources & Environmental Planning
Saccarappa Falls Nature-Like Fishway Modeling and Design
Innovative 3D CFD modeling was used to design a fishway to mimic natural bedrock following removal of tow spillway dams.