Mass flowrate measurement using the swirl motion in circular conduits

Abstract

In this paper, a method of mass flow measurement was presented based on swirl motion motivated by specific shapes of swirlers. The measuring principle of the method has been proposed by theoretical analysis and has been verified by experiment and numerical simulation. The relationship between the average axial velocity (vz̅) and the static differential pressure between the pipe wall and pipe center of a cross section downstream of a swirler (∆P) was especially emphasized. It shows that vz̅ is in direct proportion to ∆P when certain fluid flows through a specific swirler. For a certain cross section downstream of a swirler, there exist two places with different radius and different corresponding tangential average velocities, whereas with the same values of tangential average acceleration. The RSM was used as the turbulence model in simulation. Compared with the experiments, the relative errors of the flow coefficient (α) are 1.25% and 4.74% for the cross sections of 2.7D and 11.8D downstream of the swirler, respectively, which are within the scope of acceptable. In addition, we conducted the numerical simulation work of the influences of swirler on α. The results show that the bigger the angle between each slice and pipe cross section and less numbers of slices will achieve less ∆P and bigger α. This method may provide an alternative way to mass flow measurement which is easier to be standardized than other nonstandard differential pressure flowmeters.