Abstract
A simple cylindrical choke-type instantaneous flow meter, responding to the change in flow rate in high frequency up to 400 Hz, has been proposed and developed by the authors. The validity of the unsteady flow meter has been confirmed experimentally through comparisons with a laser Doppler flow rate sensor and gear motor-type flow meter. However, to apply the flow meter for practical use, there are problems still to be solved how the measurement dynamic accuracy is influenced due to the upstream flow condition.
In this research, particularly, the influence on measurement accuracy due to the existence of coaxial dynamic jet-flow velocity profile in front of the chokes is investigated experimentally.
In addition, a simple mathematical model of the pressure drop of the choke under the influence of the dynamic jet is proposed. The theoretical results are in good agreement with the experimental results. It is also confirmed that the equipment of newly-devised rectifiers upstream the chokes give sufficient effect to avoid any measurement error due to the unsteady jet flow.
