Steady and transient flow structure in a rotameter with a ball float

Abstract

Dimensions and material specifications of a commercial rotameter were used for investigating steady and transient flow structure in a rotameter with a ball float. Since drag coefficient of sphere versus Reynolds number is well known and the range of the commercial rotameter is given, the investigation relies on strong validation data. An axially symmetric geometric model is used for steady analysis of the system as the initial step of the investigation. Assessing the proper mesh structure and turbulence model is aimed for this step. Then full three dimensional solid model is put into transient analysis with RANS and LES models. Vortex shedding frequency, Strouhal number and drag coefficient values are evaluated. Vortex induced vibrations are assessed according to transient results. The work is a preliminary study for future investigation on rotameter floats. The framework of future studies is also presented.