G. Ficco, L. Canale, M. Dell’Isola, L. Lanza, A. Malengo, F. Saba, L. Solofrizzo
Individual metering for heating and cooling application has been recognized as an effective tool to improve energy efficiency in buildings in EU. Hence, thermal energy meters are widely spreading in district heating networks and in buildings served by a central heating/cooling source. By a legal metrology point of view, while type approval and initial verification of thermal energy meters are regulated by MID and harmonized standards EN 1434, no technical common procedure is still available in EU for subsequent verifications both in laboratory and on the field and member states are tackling...
FLOMEKO 2022
· TC9
· 2022
· 10.21014/tc9-2022.097
· Download
M.D. Schakel, W. Stiphout, R. Pettinen, M. Zabihigivi, U. Wagner
Exhaust flow meters (EFM) measure the amount of exhaust gas during type approval tests of diesel and petrol fuelled vehicles. They are embedded in portable emissions measurement systems (PEMS), together with analysers which measure pollutants in the exhaust gas. The European Union adopted Real Driving Emissions legislation in 2016 - 2018 in which real-driving emission tests using PEMS are a requirement for type approvalof vehicles. SI-traceable calibration of the exhaust flow meter and analysers in PEMS for real driving conditions is a challenging task. Currently a conformity factor is...
FLOMEKO 2022
· TC9
· 2022
· 10.21014/tc9-2022.096
· Download
Peijuan Cao, Yuhan Xiang, Chunhui Li, Han Zhang
To investigate the influence of complex body temperature distribution, especially the temperature drop near the throat on the discharge coefficient Cd of sonic nozzles, an adiabatic sonic nozzle with the throat of 2 mm and temperature acquisition systems including insulation sleeve with 15 mm Polytetrafluoroethylene (PTFE) and 5mm pearl cotton, multichannel data collector, three T type thermocouples, were established. Moreover, this system can be directly installed on the 100 L pVTt facility with or without insulation sleeve at National Institute of Metrology of China (NIM), to obtain these...
FLOMEKO 2022
· TC9
· 2022
· 10.21014/tc9-2022.095
· Download
Chunhui Li, Rundong Qi, Xiaoyi Zhu, Peng Cao
With the atmospheric air as the working fluid, the premature unchoking phenomena were investigated with 18 sets of critical flow Venturi nozzles under 8 types of upstream flow conditions. Unlike the available research, there were no clear relationship between the upstream flow condition and the flow rate fluctuation and flow rate recovery for the premature unchoking phenomena. However, the diverse and unsteady characteristics of the premature unchoking phenomena were shown. With the comparison of upstream flow conditions, the new disturbance might be resulted from the “improper” upstream...
FLOMEKO 2022
· TC9
· 2022
· 10.21014/tc9-2022.094
· Download
G. Bobovnik, P. Sambol, R. Maury, J. Kutin
Critical flow Venturi nozzles (CFVNs) are very stable and widely used secondary standards for gas flow rate measurements. The current study presents the first step in introducing CFVNs in the traceability scheme for gaseous hydrogen. The study was arranged in the framework of a Joint Research Project (EMPIR – MetHyInfra) and deals with the characterisation of the hydrogen discharge coefficient and the identification of a potential alternative gas for calibration of nozzles. The presented experimental study was made for two CFVNs with throat diameters of 0.175 mm and 0.436 mm. Tests were...
FLOMEKO 2022
· TC9
· 2022
· 10.21014/tc9-2022.093
· Download
S. Weiss, B. Mickan, J. Polansky, K. Oberleithner, M. Bär, S. Schmelter
This numerical study investigates the flow through a cylindrically shaped critical flow Venturi nozzle regarding the transitional behavior of the boundary layer inside the nozzle throat region. For the flow simulations, two different turbulence modeling approaches were used, and the simulation results were validated by comparison with experimental data. Characteristic quantities for describing the boundary layer development, namely the displacement and momentum thickness, were analyzed within the cylindrical part of the nozzle and compared with theoretical predictions based on integral...
FLOMEKO 2022
· TC9
· 2022
· 10.21014/tc9-2022.092
· Download
N. Takegawa, N. Furuichi
Gas flow measurement is indispensable for social activities. Critical flow nozzles used for flow standards have been improved in ISO 9300 in 1990 and 2005. However, there are still issues regarding their rational shape. The main reason is that it is difficult to measure the flow velocity in the nozzle with low disturbance and high accuracy, although various velocity measurement methods have been proposed.In this paper, we developed a recovery temperature anemometry (RTA) to measure the flow velocity from micrometer-order temperature sensors. The validity of RTA was verified through...
FLOMEKO 2022
· TC9
· 2022
· 10.21014/tc9-2022.091
· Download
Peijuan Cao, Junying Sun, Han Zhang, Chunhui Li, Liang Wang
The boundary layer transition of sonic nozzle is affected by many factors, including Reynolds number, macro structure (throat diameter), meso-micro surface structure (wall roughness, waviness), turbulence intensity, wall heat transfer and so on. Therefore, in order to analyse the influences of macrostructure, meso-micro surface structure and turbulence intensity on boundary layer transition, the Cd and geometric dimension (throat diameter, d, average roughness, Ra, maximum roughness, Rz, and waviness, wa) of sonic nozzles with throat diameter of 1.919 mm, 3.808 mm, and 7.453 mm were...
FLOMEKO 2022
· TC9
· 2022
· 10.21014/tc9-2022.090
· Download
Feng Gao, LiFen Wan, Tao Wang, QiMing Li, Yong Wang, Qian Cheng
A test system for the critical back pressure ratio (CBPR) of sonic nozzle was built in Hubei Institute and Measurement and Testing Technology, which was based on the high pressure sonic nozzle gas flow standard facility. The system used a gas volume flowmeter to judge the CBPR. A pressure reducing valve was installed upstream of the gas volumetric flowmeter and the back pressure ratio was adjusted by the valve downstream of the sonic nozzle. The experimental study on the CBPR at different Reynolds numbers was carried out. The results showed that for a nozzle with the positive pressure...
FLOMEKO 2022
· TC9
· 2022
· 10.21014/tc9-2022.089
· Download
L.Saidoripov, A. Stetsenko, Y. Glova, V. Naumenko, O. Ukolov
The problem of water resources in Central Asia and, especially, in the Republic of Uzbekistan, requests to keep a high-quality and accurate accounting of water and/or liquid consumption using water flow meters of various types, classes and modifications. In turn, there is a need (in the Republic of Uzbekistan - once every two years) to verify and calibrate liquid flow meters, using a specific verification facility. Following the Resolutions of the President of the Republic of Uzbekistan No. PP-2935 dated April 28, 2017, and No. PP-4059 dated December 12, 2018, on December 2018 № PP-4059 for...
FLOMEKO 2022
· TC9
· 2022
· 10.21014/tc9-2022.088
· Download