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...
Starting from the demand of solving the reliable calibration mode of gas flow standard device, the concept of synchronous mutual-verification of flow standard device is presented in this paper. On this basis, the two system mutual-verification device of positive pressure critical flow sonic nozzle gas flow device and inlet type bell prover gas flow device is established, and advanced control system circuit design is adopted to realize the two system automatic control. The high precision roots flowmeter is used as the mutual-verification instrument. The uncertainty (k = 2) of the two sets of...
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...
Bell Prover is the primary standard system for low-pressure gas by National Measurement Laboratory. When Bell Prover conducts calibration, the density of the gas inside the bell jar must be determined by the measurement of the pressure and temperature of the gas inside the bell jar. It is essential to accurately measure the representative temperature of the bell jar interior. After the system is redesigned in temperature control and temperature measurement methods, the half interval of the measurement error due to temperature stratification inside the bell jar is reduced from the original...
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...
When the fluid passes through the elbow, it is easy to produce secondary flow, eddy flow, etc. The velocity distribution in the sonic flow channel is not symmetrical, which has an impact on the measurement accuracy of the flowmeter. In order to study the influence of turbulence on flowmeter by means of modelling and simulation, the measurement effect of G16 single-channel flowmeter is firstly studied under this condition. The condition is that the inlet pipe is double-bend pipe and half-moon double-bend pipe, and calculate the flow error in the two cases relative to the straight pipe. The...
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...
During machining along a complex tool path, it is difficult to connect the change in the amplitude and in the frequency of the recorded vibration signals to the actual state of tool wear. In this article, a method is presented in which the tool wear processes that occur during the machining of a complex geometry (cooling pocket formed on the ceramic coating of the turbine blade) can be evaluated based on the vibration data series recorded during the machining differentiating of some elements of the complex path movement performed by the tool.
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.
This paper presents the failure analysis and diagnostic of a hydraulic turbine. Shortly after a maintenance revision the thrust bearing of the turbine was destroyed when the turbine was put into operation. The damaged bearing was examined and the possible causes discussed. To identify the problem that led to the failure of the thrust bearing, a comprehensive on-site measurement campaign was done. Vibrations, pressures, temperatures and operating parameters were acquired at different operating conditions of the turbine. The analysis of the data allowed to determine the source of the problem...