Development and characterization of a capacitance-based microscale flowmeter

Current microflowmeters can be used accurately in laminar flow conditions for Reynolds (ReRe) number greater than 50 or when μPIV trace particles are used. However, many applications require accurate measurement of very low flow rates using a simple and reliable apparatus at low cost. Design and analysis of a capacitance-based flowmeter has enabled the successful construction and testing of an accurate low Reynolds number flow sensing device for liquid applications. Experimental results revealed that the devised microscale flowmeter can perform adequately at Reynolds number as low as 5 with a signal-to-noise ratio greater than 40. Experimental results also revealed that the electrical capacitance of the devised flowmeter sensing element is directly proportional to the flow rate and Reynolds number, and can be used without adjusting the testing fluid’s physical properties.