Development of Micro-Flow Meter

摘要

A simple measurement method of micro flow rates with high precision is proposed for industrial use. Poiseuille flow is obtained within a very short entrance length in the case of low Reynolds number flows. A locally accelerated thermal flow is produced by a small spot heater, which is placed in the center part of the downwardly directed Poiseuille flow. Flow rate in a pipe can be obtained by using the linear relationship between the locally accelerated velocity due to the buoyancy force and the flow rate (maximum velocity is two times larger than the mean velocity in a Poiseuille pipe flow). The validity of measuring the flow rates below 0.1mL/min was confirmed by the numerical simulation using the unsteady two-dimensional Boussinesq equations.