Towards an Optimal Pressure Tap Design for Fluid-Flow Characterisation at Microscales

Area of Science:

• Microfluidics
• Fluid dynamics
• Experimental methods

Background:

• Accurate fluid pressure measurement in microchannels is challenging.
• Optimal design guidelines for microfluidic pressure taps are lacking.
• Existing pressure tap designs may compromise measurement accuracy.

Purpose of the Study:

• To investigate the impact of pressure tap geometry on microchannel pressure drop measurements.
• To identify optimal pressure tap designs for enhanced measurement accuracy.
• To provide guidelines for pressure tap design in microfluidic systems.

Main Methods:

• Fabrication of 18 distinct microchannel pressure tap designs using soft-lithography.
• Parametric study varying sub-channel width (w), tap radius (R), and tap angle (α).
• Measurement of pressure drop in straight microfluidic channels using DI water across a range of flow conditions (creeping flow to Re ≈ 100).

Main Results:

• Microchannel pressure taps with smooth contours (radius R) and a sub-channel width (w) of 108 μm demonstrated superior performance.
• A specific design with R = 50 μm achieved results within approximately 5% of the analytical solution.
• The study identified key geometric parameters influencing pressure measurement accuracy.

Conclusions:

• Smooth-contoured pressure taps with optimized dimensions significantly enhance microfluidic pressure measurement accuracy.
• The findings offer practical design recommendations for microfluidic experimentalists.
• This research contributes to more reliable fluid pressure characterization in microscale systems.