Application of Embedded Capacitive Pressure Sensors in Pressure Drop Measurement of Microchannels

The measurement of pressure drops within microchannels is pivotal for exploring microfluidic flow dynamics and advancing microfluidic device technology. Traditionally, assessing liquid pressure drops in silicon microchannels has necessitated alterations to the original design of the microchannels to accommodate the integration of small pressure sensors. This adaptation, however, introduces a limitation: the small size of the sensor compromises its sensitivity, thereby impairing the reliability of pressure drop measurements. This study explored an approach to the application of capacitive pressure sensors, designed to be seamlessly embedded into microchannels, to accurately measure pressure drops in silicon microchannels. By carefully regulating the outlet pressure, the overall absolute pressure in the microchannel was increased without affecting the pressure drop values. This approach enhanced the capacitive pressure sensor's sensitivity across a broader operational range. The findings from pressure drop tests conducted on a straight microchannel, possessing a hydraulic diameter of 524 μm and examined across a Reynolds number range of 383.8 to 1644.9, align with established macroscopic theories.