NIST logo

Publication Citation: Accurately Measuring Unsteady Water Flows Using A Dynamic Standard

NIST Authors in Bold

Author(s): Iosif I. Shinder; Michael R. Moldover;
Title: Accurately Measuring Unsteady Water Flows Using A Dynamic Standard
Published: April 01, 2009
Abstract: We recently presented and tested a model for a dynamic gravimetric standard for steady water flows. In the range 10 kg/s to 60 kg/s, the difference between the dynamic standard and NIST's static primary standard was 0.015 % with a standard deviation of 0.033 %, Here, we extend the model for the dynamic gravimetric standard to account for unsteady flows and we account for the different response times of the dynamic standard and an electromagnetic flow meter (EMF). After these improvements, we measured water flows with diverse time dependences during 100 s collection intervals. These flows averaged 12 kg/s; however, the flows ramped or stepped up or down 5 kg/s. When integrated over the collection interval, the difference between the dynamic standard and a statically-calibrated EMF was 0.008 % with a standard deviation of 0.012 %. This agreement justifies the further study of the dynamic standard, particularly at higher flows where the mechanical simplicity of a dynamic standard might reduce the cost of accurate measurements.
Proceedings: Measurement Science Conference
Location: Anaheim, CA
Dates: March 23-27, 2009
Keywords: flow measurement; primary standard; dynamic gravitational method; flow metrology
Research Areas: Calibrations (Mechanical)
PDF version: PDF Document Click here to retrieve PDF version of paper (278KB)