18.01.2010
In November 2009, a highly regarded two-day seminar on "Technology and procedures of water flow measurement" was organised by the National Institute of Metrology (NIM) of the People's Republic of China, with the participation of PTB. The seminar was very wide ranging as regards contents and - besides questions on measurement uncertainty, traceability, relevant standards and legal regulations - also dealt with numerous interesting technical aspects.
On 17 and 18 November 2009 the "Seminar on Water Meters – International Recommendations and Water Flow Measurement Technology" took place at NIM in Peking. The purpose of this seminar was the bilateral exchange of knowledge and experience between NIM and PTB as well as the transfer of knowledge to representatives of different local metrology institutes from China's provinces.
Figure 1: Speaker Dr. R. Engel, PTB Braunschweig, and translator Dr. Li, NIM, Peking
While from the PTB's side, above all, such fundamental questions as testing facility requirements, the analysis of the measurement uncertainty, ensuring traceability, and international standardisation were in the foreground, from the Chinese side, also some problems very specific to China were presented. Here, for instance, as a very special metrological challenge, the flow measurement in the water inlet channels to the hydroelectric power plant of the Three Gorges Dam on the Yangtze River is to be mentioned. The dimensions of the flow "measuring instruments" are impressive here: after all, these are flow channels with a diameter of a little more than 12 m, in which the flowrate is to be determined by means of an 18-jet ultrasonic measuring device. The exact predetermination of the metrological properties is particularly complex both in its scientific and technical construction and in its concrete constructive design. For obvious reasons, the entire functioning flow measurement facilities are fixed components of the total dam construction and are, therefore, first constructed directly on site. All metrologically relevant investigations are, therefore, carried out on a model with a scale of 1:25 and then – also utilising CFD simulations – transferred to the original proportions.
Figure 2: Participants in the seminar "Technology and procedures of water flow measurement"
In the subsequent exchange of experience, the manifold problems in designing and constructing high-accuracy flow standard facilities were discussed in an extensive joint series of talks. The starting point here was the hydrodynamic test field of PTB and the metrology-relevant detailed solutions implemented there. A further aspect dealt with the concrete approaches that are pursued at PTB to guarantee the traceability of flow measurements of liquids. This question is not least of importance for NIM, as efficient and high-precision flow standard facilities also exist in different metrology institutes of China's provinces.In the subsequent exchange of experience, the manifold problems in designing and constructing high-accuracy flow standard facilities were discussed in an extensive joint series of talks. The starting point here was the hydrodynamic test field of PTB and the metrology-relevant detailed solutions implemented there. A further aspect dealt with the concrete approaches that are pursued at PTB to guarantee the traceability of flow measurements of liquids. This question is not least of importance for NIM, as efficient and high-precision flow standard facilities also exist in different metrology institutes of China's provinces.
In conclusion, the Departmental Head responsible, Ms Wang Chi pointed out the large interest of NMI's professional colleagues with regard to a further cooperation with PTB in the field of flow measurement.
In conclusion, the Departmental Head responsible, Ms Wang Chi pointed out the large interest of NMI's professional colleagues with regard to a further cooperation with PTB in the field of flow measurement.
Contact person:
Dr. Rainer Engel, Department 1.5, e-mail: rainer.engel@ptb.de