報告題目：Flow Visualization in Spacer Filled Channels with Particle Image Velocimetry
報 告 人：G. Glenn Lipscomb (University of Toledo)
報告時間：2015年10月09日上午9：30
報告地點：化學樓二樓一號會議室
報告人簡介：
Prof Lipscomb obtained his PhD from University of California at Berkeley, USA in Chemical Engineering. He worked in The Dow Chemical Company in the California area for 2 years and as an Assistant Professor in University of Cincinnati for 5 years before joining the Department of Chemical & Environmental Engineering in University of Toledo. He is the Department Chair from 2004 to the present. Prof Lipscomb has published over 50 papers and several patents.
報告簡介：
Membranes in the form of sheets are used to form spiral wound membrane modules for a wide variety of separations ranging from seawater desalination to carbon dioxide capture from coal-fired power plants. Spacers are a critical component of these modules. Spacers create and maintain uniform flow channels for the feed and permeate flows. Spacers also are used to mix fluid within the channel to enhance mass transfer. Unfortunately, spacers increase pressure drop. This increase depends strongly on spacer geometry.
Computational fluid dynamics (CFD) has been used extensively to investigate flows within spacer filled channels. The CFD simulations have included two-dimensional and three-dimensional simulations for both steady and unsteady flows. The channel most commonly is approximated by a periodic cell to reduce the required computational resources. This body of work has examined the dependence of velocity field and pressure drop on spacer geometry variables including filament diameter, filament shape, filament spacing, angle between filaments and fluid attack angle.
Simulation results typically are validated by comparison to experimental measurements of pressure drop. Limited point-wise, volumetric comparisons of velocity fields with experimental measurements are available.
Detailed comparisons of experimental velocity fields, obtained using Particle Image Velocimetry (PIV), with simulation results are reported here. PIV captures the movement of seed particles in the flowing fluid to determine the local fluid velocity. Measurement of the two velocity components in the interrogation plane are presented for three types of spacers: 1) symmetric, 2) asymmetric, and 3) static mixing. The results indicate CFD simulations using a periodic cell generally are in good agreement with experimental results. The greatest errors in experimental measurements are associated with particle distribution throughout the flow channel and orientation of the experimental flow cell.
Stereographic measurements of all three velocity components in the interrogation plane also are reported. The out-of-plane velocity component is small for the symmetric and asymmetric spacers and values are near the resolution level of the experiment. However, good agreement is found for the static mixing spacer which possesses much larger out-of-plane velocities.
The results suggest CFD simulations provide good predictions of spacer performance. This further validates the use of CFD to optimize spacer geometry.
