New Flow Equation for Rotameter

Currently used flow equation of rotameter was obtained by analogy of orifice meter, which is not rigorous in theoretic. In this paper, according to the fluid motion characteristics in rotameter, the integrity form flow equation of rotameter is derived based on flow around a body, and the tapered tube rotameter flow equation with dead zone error is also derived, the experimental results related flow coefficient are explained very well by means of drag coefficient of flow around a body. The experimental results show that new flow equation derived in this paper is correct. Meanwhile, the reason that current used flow equation has been using ever since is explained. These working are very important to perfect rotameter theory and guide design.