Date on Master's Thesis/Doctoral Dissertation

7-2007

Document Type

Master's Thesis

Degree Name

M. Eng.

Department

Chemical Engineering

Committee Chair

Berson, Robert E. (Eric)

Subject

Fluid dynamics; Cell culture

Abstract

Orbital shakers are commonly used in the cell culture industry due to their ease of use, but the fluid dynamics of this system have not been extensively modeled as the system is difficult to quantify analytically. It is desirable to understand how cultured cells respond to fluid forces as the result of motion of a dish on an orbiting platform under varying flow conditions. Wall shear stresses are commonly accepted as the primary influence affecting characteristics of anchored cells subjected to fluid flow. Cells become aligned and elongated with the direction of flow when shear stresses are experienced. In this work, FLUENT, a commercial CFD package is utilized to model fluid behavior in these dishes. To simplify computational effort, the investigation is reduced to the study of the following three dimensionless parameters: the Stokes Number, the Froude Number, and the Slope Ratio. It is desirable to identify how the fluid behaves at low and high values for each of these parameters and where the transition from low to high occurs for each of these values. The study yielded the following findings. The Stokes Transition occurs at a Stokes Number of 4.1±0.1 for a Froude Number of 1.0 and a Slope Ratio of 1.0 and results in a localized increase in the slope of maximum WSS vs. Stokes Number. The Froude Transition occurs at a Froude Number of 0.25±0.05 for a Stokes Number of 5.0 and a Slope Ratio of 1.0 and results in a localized increase in the slope of maximum WSS vs. Froude Number. The Slope Transition occurs at a Slope Ratio of 1.25±;0.15 for a Stokes Number of 5.0 and a Froude Number of 1.0 and results in a localized increase in the slope of maximum WSS vs. Slope Ratio.

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