Computational Modeling and Simulation of a Single-Jet Water Meter

摘要

A single-jet water meter was modeled and simulated within a wide measuring range that included flow rates in laminar, transitional, and turbulent flow regimes. The interaction between the turbine and the flow, on which the operating principle of this kind of meter is based, was studied in depth from the detailed information provided by simulations of the three dimensional flow within the meter. This interaction was resolved by means of a devised semi-implicit time-marching procedure in such a way that the speed and the position of the turbine were obtained as part of the solution. Results obtained regarding the turbine's mean rotation speed, measurement error, and pressure drop were validated through experimental measurements performed on a test rig. The role of mechanical friction on the performance of the meter at low flow rates was analyzed and interesting conclusions about its influence on the reduction of the turbine's rotation speed and on the related change in the measurement error were drawn. The mathematical model developed was capable of reproducing the performance of the meter throughout the majority of the measuring range, and thus was shown to be a very valuable tool for the analysis and improvement of the single-jet water meter studied.