Since ultrasonic flowmeter is sensitive to the flow field. Insufficient development of the flow field such as vortex and asymmetric flow will cause deviations in the measurement results. It has become a common method to accelerate the stabilization of irregular fluids to a fully developed state by a flow conditioner. The flow conditioner is a device installed upstream of the flowmeter to accelerate the stabilization of the irregular flow field, eliminate abnormal flow, and reduce the influence of swirling flow.In practical application, the correlation between flow conditioner and flow meter model has also become an important obstacle restricting the design, compatibility and popularization of flow conditioner. It is an exploratory and meaningful work to design a universal flow conditioner and propose a flow field optimization evaluation method and other basic theories and common key technologies of flow measurement.This paper introduces the self-designed universal flow conditioner, and focuses on the flow adjustment effect evaluation method based on CFD.In order to verify the adjustment effect of the combined flow conditioner, the simulated calculation is carried out and the flow field adjustment effect is compared with that of the plate-type flow conditioner.When the inlet flow rate is 20 m/s, the simulation results show that the combined flow conditioner has excellent performance in eliminating flow field distortion at about 15D downstream the flow conditioner, while the flow velocity distribution in the axial direction can also be optimized to a fully developed symmetrical state.

In this study, the leakage noise and the pressure field generated by the underground pipeline leakage were calculated by the Computational Fluid dynamics (CFD) software ANSYS Fluent based on the Ffowcs Williams_x005f_x0002_Hawkings (FW-H) equation and Large Eddy Simulation (LES). Different leakage hole shape were carried out in the simulation. Weconsidered two conditions for the pipeline: the pipeline was surrounded by the air and the soil simulated by the porous materia. The second one was closer to the real situation. In the first condition, the results demonstrated that the aerodynamic noise frequency mainly ranged from 0 Hz to 500 Hz that was in good agreement with the literature. The thin and ellipse shape with larger pressure loss got the maximum overall sound pressure level (OASPL) due to stronger interaction between the wall and the fluid. The farther the receiver was from the leakage, the OASPL obtained by the receiver was lower. In the second condition, the frequency range was mainly distributed under 300 Hz and was different from the first condition. Besides, the OASPL was also lower than the first condition. These results were due to the soil characteristics of reducing velocity and pressure that contributed to lower wall stress and pressure variation.

The rationale for the expediency of using a diverter with a variable geometry of the nozzle exit in a calibration unit with weighing devices (hereinafter – Unit) is presented for the first time in this paper. The design, operating principle and timing diagram of a diverter with a variable geometry of the nozzle exit are described in this. The local hydrodynamic characteristics of the water flow in the nozzle exit of the diverter are made by a Pitot probe. The cut-off width of the diverter nozzle was changed at fixed values of the water flow rate. The metrological characteristics of the Unit are determined by the comparison method using a comparison standard. The effect of the width of the nozzle cut on the metrological characteristics of the Unit in the investigated range of the liquid flow rate has been established. The graphical dependencies of type τ = f(U(Qm ))and Qm=f (U (Qm )) of the expanded measurement uncertainty of the Unit when reproducing the unit of the mass flow rate of the liquid on the time interval of measurements and on the mass flow rate of the liquid are presented (k = 2, P = 0.95). Based on the research results, the optimal values of the nozzle exit width andmeasurement time intervals were determined depending on the values of the mass flow rate of the liquid when using a diverter with a variable geometry of the nozzle exit. Expansion of the range of operation of weighing devices included in Unit is justified.

The first formal comparison of gas flow primary standard facilities was conducted in China during 2016 ~ 2020. There were 4 participants from China, and PTB was invited as the link lab to connect this comparison with the serial key comparisons of CCM.FF.K5. There were 4 sets of sonic nozzles as the transfer meters, with which there were totally 105 set of measured results were conducted with the Reynolds range (4.8 × 10^4 ~ 1.1 × 10^7). To cover the Reynolds range, a theoretical equation of discharge coefficient was presented with only one parameter, which was used to evaluate the discharge coefficient at the exact same Reynolds number of the measured points. The evaluation model and uncertainty of the theoretical equation was presented. The degree of equivalence of En was finally evaluated. Among all 105 sets of measured results, there were 96 sets of results with En ≤ 1; while there were 8 sets of results with 1 < En ≤ 1.2.

The topic of the paper is the presentation of the methodology and the results of forecasting energy generation by the wind turbine with the utilization of three regression methods: factorization machines, decision trees and random forests. The data coming from the wind farm in Turkey was first preprocessed to facilitate prediction task. The prediction of the eneregy production.