Numerical study on the flow characteristics in swirl meter

Abstract

The swirl meter (vortex precession flow meter) popularly used in natural gas industry is a kind of velocity flow meter with high turndown ratio and well performance in low flow measurement and other known advantages. In order to further understand the flow pattern of swirl meter to further improve its performance, computational fluid dynamics simulations are used to simulate the flow and predict the coefficient for swirl meter at different flow rates. Using renormalization group k–ε turbulent model and SIMPLEC algorithm, numerical simulations have been performed through commercial codes Fluent, and meter coefficients are also obtained experimentally to validate the numerical results. The simulated velocity and pressure in swirl meter are analyzed in detail, which are time-averaged distributions during a time period based on the transient numerical simulation. It is found that centerline pressure is lowest at the outlet of the swirler and rises gradually along the axial direction. While near-wall pressure presents an opposite variation tendency, it is significantly low at the end of throat due to strong influence of vortex precession. Centerline velocity increases as the flow approaches throat and reaches its maximum at center region of throat, and then it decreases and keeps relatively stable at downstream of divergent section. Both time-averaged pressure and axial velocity distributions are axisymmetric, and pressure variation is small on the cross section at the end of throat, although vortex precession is strong.