Abstract
Visualizations of the flow patterns in a square-square contraction were undertaken using streak line photography, and detailed velocity field measurements were conducted using a Particle Image Velocimetry technique. We analyze the effect of contraction ratio on the flow patterns observed with a Newtonian and a Boger fluid. For the Newtonian fluid, the experimental results are compared with numerical simulations performed using a Finite-Volume method, and excellent agreement is found. For the viscoelastic case, we observe complex flow patterns that are dependent on the contraction ratio. For low contraction ratios strong divergent flow is observed upstream of the contraction, which is consistent with the findings of Alves and Poole [1]. On the other hand, for high contraction ratios no upstream divergent flow is observed, except in the vicinity of the re-entrant corner, where a localized atypical divergent flow is observed. For all contraction ratios studied (CR = 2.4, 4, 8 and 12), increasing the Deborah number leads to a strong elastic vortex enhancement upstream of the contraction, until a periodic complex flow is established at higher flow rates.
Original language | English |
---|---|
Title of host publication | AIChE Annual Meeting, Conference Proceedings |
Subtitle of host publication | 2007 AIChE Annual Meeting |
Publication status | Published - 2007 |
Event | AICHE Annual Meeting - Salt Lake City, Utah, United States Duration: 4 Nov 2007 → 9 Nov 2007 |
Conference
Conference | AICHE Annual Meeting |
---|---|
Country/Territory | United States |
City | Salt Lake City, Utah |
Period | 4/11/07 → 9/11/07 |
Keywords
- viscoelastic fluid flow
- Three-dimensional flow
- square-square contractions