Splitter imperfections in annular split-flow thin separation channels: experimental study of nonspecific crossover

Area of Science:

• Fluid dynamics
• Separation science
• Microfluidics

Background:

• Split-flow thin (SPLITT) separation device performance is sensitive to channel uniformity and splitter placement.
• Nonspecific crossover, sample transport without an applied field, indicates splitter irregularities.
• Computational fluid dynamics (CFD) can predict crossover due to splitter imperfections, assuming convection-driven transport.

Purpose of the Study:

• To validate CFD predictions of nonspecific crossover by comparing them with experimental results.
• To investigate the impact of severe splitter geometry imperfections on SPLITT device performance.
• To confirm that CFD can accurately quantify crossover contributions from geometrical defects.

Main Methods:

• Experimental measurement of nonspecific crossover in a SPLITT device with a deliberately bent splitter.
• Systematic variation of inlet and outlet flow rate ratios.
• Comparison of experimental data with CFD predictions.

Main Results:

• A severely bent splitter induced significant nonspecific crossover across various flow conditions.
• Experimental results showed good agreement with CFD predictions.
• Experimentally observed crossover was slightly higher than predicted, likely due to factors not fully modeled.

Conclusions:

• CFD is a reliable tool for predicting nonspecific crossover caused by geometrical imperfections in SPLITT devices.
• The study confirms that geometrical defects, even severe ones, can be accurately modeled.
• This validates the use of CFD for optimizing SPLITT device design and understanding separation performance limitations.