Analyse d'écoulements liquides ou gazeux en micro-conduites : découplage des incertitudes expérimentales

Analysis of gas and liquid flows in micro-ducts: delinking of the experimental uncertainties » The different sources of uncertainty that occur during the experimental study of steady flows through micro-ducts is analyzed. It is noticed that the lack of precision when measuring the geometrical dimensions of the sections plays a crucial role. A method is proposed to avoid this source of uncertainty. It is illustrated with two examples. The first one is relative to gaseous flows in rectangular micro-ducts. The experiment allows to show the validity of a second-order slip-flow model, for Knudsen numbers up to 0.20, while a classic first-order model is no longer precise above 0.05. The second example is relative to liquid flows in trapezoidal micro-ducts. A deviation from the classic Poiseuille law is clearly revealed, for Reynolds numbers between 10 -1 and 10 -3 . A relation between Reynolds and Poiseuille numbers is proposed.