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Micro channels for applications in liquid dosing and flow rate measurement

: Richter, M.; Woias, P.; Weiß, D.

Puers, R. ; Catholic Univ., Leuven:
Eurosensors X. Proceedings
Leuven: Catholic University, 1996
ISBN: 90-803282-1-9
pp.1297-1300, Bd.4
Eurosensors <10, 1996, Louvain>
Conference Paper
Fraunhofer IFT; 2000 dem IZM eingegliedert
flow rate measurement; liquid dosing applications; micro channel; physical sensor

To investigate the performance of microengineered fluid channels in liquid dosing applications, flow rate measurements were performed with various channel geometries in a range from 0.01 ml/min up to 1000 ml/min. An optical flow measurement technique was developed to enhance the measurement range into the desired low flow range (10(exp -3)ml/min to 1 ml/min), and was compared to a standard gravimetric method, which is preferably used for flow rates above 1 ml/min. In addition, influences of the temperatur-dependent viscosity and effects arising from fluidmechanical characteristics were studied. These influences were also calculated from laminar flow theory and semi-empirical models to obtain a theoretical model. It was found, that the theoretical model is able to describe the measurement results well agreeing in the whole flow range. The model was implemented on a PC-based system, which measures the pressure drop across the microchannel and the fluid temperature and calculates the flow . In a temperature range from 20 deg C to 50 deg C an excellent compensation effect was found.