Abstract: Numerical simulation is applied to design the internal flow passage of a fluidic flowmeter and research on the velocity distribution and pressure distribution of the flow field in the fluidic flowmeter, as well as the mechanism of fluid alternation and oscillation induced by the Coanda effect. The results of the simulation indicate that the deflection of main jet is always accompanied with strength alternation of two vortexes acting on the main jet together. Subsequently a fluidic flowmeter prototypeis optimized based on the simulation model. Experimental study is carried out to verify the effects of fluidic vibration and the characteristic relationship between conduit velocity and vibration frequency. A fluidic flow sensor with a measuring range from 0.55 m/s to 6.5 m/s for gas medium and an accuracy grade higher than grade 2 is finally developed. Hence effective methods of structural improvement and optimum design for fluidic flowmeter are provided.

Key words: Coanda effect, Fluid vibration Flow field simulation, Fluidic flowmeter