A transit-time flow meter, using periodic temperature fluctuations as tracers, has been developed for measuring liquid flow as small as 0.1 ml/min in microchannels. By injecting square waves of heat into the liquid flow upstream with a tiny resistance wire heater, periodic temperature fluctuations are generated downstream. The fundamental frequency phase shift of the temperature signal with respect to the square wave is found to be a linear function of the reciprocal mean velocity of the fluid. The transit-time principle enables the flow meter to have high accuracy, better than 0.2%, and good linearity. This flow meter will be used to measure and control the small liquid flow in microchannels in flow injection analysis. Review of Scientific Instruments is copyrighted by The American Institute of Physics.
Bibliographical noteCopyright (1988) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.
Yang, C., Kymmel, M., & Søeberg, H. (1988). A transit-time flow meter for measuring milliliter per minute liquid flow. Review of Scientific Instruments, 59(2), 314-317. https://doi.org/10.1063/1.1140247