Measurement of flow rate at terminal device

Measurement of air flow is an important part of the commissioning and monitoring of ventilation installations both for residential and tertiary sectors. In the case of the measurement of flow rate at air terminal devices, an experimental approach highlights the practical limitations related to the usual methods available for on site measurements and the influence of the used instruments. The purpose of the present work is to make a critical analysis of the on site air flow measurement methods with regard to measurement configurations

Measurement of air flow in duct by velocity measurements

To measure a flow in a closed duct, one of the available methods is to explore the velocity field. With this method, the quality of the flow measurement is very dependent on the location of the velocity measurement points in the duct section. Recommendations about velocity schemes are proposed in international standards (ISO 3966, ISO 7145, EN 12599 …) for circular and rectangular ducts. These recommendations assume that a turbulent flow profile is established. This requires flow profiler and/or long straight lengths upstream and downstream the measurement section. On site, these recommendations are difficult to apply strictly because conditions of straight lengths are often not available. Secondly, the velocity measurement schemes proposed in standards are often time consuming and users prefer sometimes to simplify them. In this case, the estimation of the measurement error is not known. A numerical study has been carried out to investigate the influence of the velocity measurement scheme on the flow measurement when the distance between disturbances and the measurement section is small in the case of circular and rectangular ducts. The results are presented in term of measurement error according to the shape of the duct, velocity scheme, number of velocity measurements, distance between disturbances and measurement section

Modelisation of Pulverisation Systems : Some Aspect of Linear Stability Analysis

International audienc

CCM.FF-K3.2011 Intercomparison for airspeed

The CCM.FF-K3.2011 comparison was organized for the purpose of determination of the degree of equivalence of the national standards for air speed over the range 0.5 m/s to 40 m/s. An ultrasonic anemometer and a Laser Doppler anemometer were used as transfer standards. Nine laboratories from three RMOs participated between July 2013 and July 2015 – EURAMET: PTB, Germany; LNE-CETIAT, France; INRIM, Italy; VSL, The Netherlands; E+E, Austria; SIM: NIST, measurements were provided at ambient conditions. All results of independent participants were used in the determination of the key comparison reference value (KCRV) and the uncertainty of the KCRV. The reference value was determined at each air speed separately following “procedure A” presented by M. G. Cox. The degree of equivalence with the KCRV was calculated for each air speed and laboratory. Almost all reported results were consistent with the KCRV