Blending of non-Newtonian fluids in static mixers: assessment via optical methods

Alberini, Federico (2014). Blending of non-Newtonian fluids in static mixers: assessment via optical methods. University of Birmingham. Ph.D.

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Abstract

The performance of KM static mixers has been assessed for the blending of Newtonian and time-independent non-Newtonian fluids using planar laser induced fluorescence (PLIF). A stream of dye is injected at the mixer inlet and the distribution of dye at the mixer outlet is analyzed from images obtained across the pipe cross section. The effect of superficial velocity, scale of static mixer, flow ratio between a primary and a secondary injected flow and finally the injection position, are investigated to determine the consequences on mixing performance. Different methods are discussed to characterize mixing performance, comparing CoV and maximum striation thickness. Conflicting trends are revealed in some experiments results, leading to the development of an areal based distribution of mixing intensity and a distribution of striation with high mixing intensity. For two-fluids blending, the addition of a high viscosity stream into the lower viscosity main flow causes very poor mixing performance, with unmixed spots of more viscous component observable in the PLIF image. The final part of the work is focused on a preliminary understanding of advective mechanisms such as shearing of non-Newtonian fluid drops and stretching of a non- Newtonian fluid filaments.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

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