Uncertainty Assessment for Determining the Discharge Coefficient <i>C</i> for a Multi-Opening Orifice

Abstract

This article contains the results of experimental studies of a multi-opening orifice with substitute constriction factor of β = 0.5 (m = 0.25), mounted in a DN50 hydraulic measuring flume. Flow measurements were taken from a progressing turbulent flow within Reynolds numbers (Re = 4700–19,500). Based on conducted experimental data, flow characteristics, and discharge coefficient C characteristics were determined. Relative expanded uncertainty of determining a discharge coefficient C was estimated within the changes of volume flow qv from 0.35 to 0.68 dm3/s, based on rules from the GUM international standard. The value, determined from uncertainty analysis, did not exceed 1.25% within the changes of Reynolds numbers 9800 ≤ Re ≤ 19,500.

Keywords

• volume flow
• multi-opening orifice
• experimental studies
• measurement uncertainty analysis