Towards a thermal noise limited micro-coriolis mass flow sensor

Accurate measurement and control of fluid flow is critical in many applications, such as gas chromatography, wind sensing and biomedical applications. Therefore, flow sensors are often the crucial component in fluidic systems. Over the last decades, the research field of micro-machined flow sensors has been ever growing due to the advantages that come with miniaturization of such sensors. The main advantages of micro-machined flow sensors are their low power consumption and their ability to measure very low flow rates. Thermal flow sensors are widely used for their high resolution. However, thermal flow sensors have to be calibrated for a specific fluid, since each fluid has a different heat capacity. On the other hand, Coriolis mass flow sensors measure true mass flow, independent of fluid properties such as density and viscosity. This has made them of great importance in the field of mass flow measurement. The first micro-machined Coriolis mass flow sensors were presented almost two decades ago. Since then, much progress has been made to improve their performance. The aim of the research in this thesis is to push the resolution of the μ-Coriolis mass flow sensor (μ-CMFS) towards the limit associated with mechanical-thermal noise. The research in this thesis focuses on limitations to the performance of a μ-CMFS related to the mechanical design and how to address these. The research can be divided into two parts: 1) Definition of the limitations to the performance of a μ-CMFS and modelling of said sensor, 2) Presentation of methods and designs which address the aforementioned limitations.