Errors of turbine meters due to swirl

Abstract

This chapter addresses the question of the error in metering of a flow with a turbine flow meter caused by swirl in the oncoming flow. The problem is approached by analyzing the signal-generation mechanism of a turbine flow meter from a fundamental fluid mechanics point of view when the oncoming flow shows departures from its calibration state. The fundamental physical mechanism in question is the driving moment experienced by the rotor of the turbine flow meter due to the aerodynamic forces on the rotor blading. Swirl in the oncoming flow belongs in this scheme to one class of possible disturbances to the calibration flow. The study brings out the salient parameters that govern the error in metering due to swirl, and the pattern of error dependance on swirl strength. © Springer-Verlag Berlin Heidelberg 2005.