A new, miniature design of a clamp-on ultrasonic transit-time difference flow meter for use in liquids is presented, with particular application to small diameter, thin walled metal pipes, opening up new areas of application, including smart water metering. The particular embodiment of the hardware is low cost and can be installed by unskilled users, and uses a type of guided wave mode that is significantly different to previous examples of clamp-on flowmeters that have used a leaky guided wave in the pipe to generate compression waves in the liquid. In the example presented in this paper, the entire liquid-pipe system acts as a wave guide, providing large amplitude ultrasonic signals with outstanding signal to noise, even from a drive voltage of just a few volts. The flowmeter is capable of measuring flow rates down to a few millilitres per second, with an accuracy better than 0.5 millilitres per second. The results presented mainly focus on 15 mm diameter copper pipes of wall thickness 0.7 mm, but the same approach works well on pipes with larger diameters and slightly thicker walls, up to around 30mm diameter in the current embodiment, In many instances, in previous work, the presence of the guided wave modes has prevented clear interpretation of the ultrasonic signals that are detected.

Water cut is one of the key parameters in the process of oil and gas production. In the present study, wepropose a microwave resonant cavity sensor(MRCS) which can work in both TM010 and TM110 modes, andestablished a water cut measurement of vertical upward oil–water two-phase flow in the range of 0-100 %. The response characteristics of the two resonant modes to water cut are analyzed by the coupling simulation offlow field and electromagnetic field using COMSOL finite element simulation software. A flow experimentisconducted with the designed MRCS measurement system. The sensitivity of the two modes resonantfrequency in different water holdup range is compared. The results show that 95 % of the experimental points’ relative errors is less than ± 5 %.It is indicated that the model can predict water hold with high accuracy, which may provide a solution for wellhead water cut measurement of oil field.

With the development of the gas-liquid two phase flow dynamics theory and the continuous improvement of two phase flowrate measurement requirements, the importance of slug flow research has become increasingly prominent. The wire mesh sensor (WMS), which consists of the perpendicular "cross-point" between the transmitting wires and receiving wires, forms a particular "hard field" measurement mode. This paper aims toinvestigate the measurement characteristics and accuracy of a 16×16-electrode conductivity WMS with a spatial resolution of 3.125 mm for gas-liquid two phase slug flow by means of flow experiments. Experimentswere performed in a 50 mm horizontal pipe with air and water as the working medium at atmospheric conditions, meanwhile, the time series data were collected by WMS. Comparing the cross sectional, a good correspondence can be found in the cross sectional direction between axial reconstructed images of fluid distribution and averaged void fraction time series. The WMS can realize the quantitative measurement of local void fraction and the qualitative spatial phase reconstruction of fluid distribution. Furthermore, distribution characteristics of the cross sectional averaged void fraction time series of gas-liquid two phase slug flow were analyzed. We found when superficial gas velocity is less than 3 m/s, the gas phase mainly exists in the form of elongate gas slug. When superficial gas velocity is around 5 m/s, it appears as typical bullet-shape gas slug. As superficial gas velocity increases to 10 m/s, the liquid slug becomes blurred and the gas phase almost penetrates through the liquid slug structures. In addition, a Probability Density Function (PDF) is generated from the instantaneous cross sectional averaged void fraction data for different flow regime conditions. The results show that the PDFs for lower superficial gas velocity case (3 m/s), two peaks in the void fraction signal are observed. Nevertheless, with an increase in superficial gas velocity, it is seen that the peak in the low void fraction region, which corresponds to the liquid slug structures, becomes much smaller even disappears.

This contribution describes a research of measurement uncertainty of industrial emissions flowing through vertical stacks and its dependence on different geometrical configurations and physical conditions. Since the legislative requirements for emission limits from industrial processes are decreasing, the higher measurement accuracy is becoming more important and new uncertainty standards needs to be implemented. Thiscontribution is a part of the research project 18NRM04 Heroes under European Metrology Program for Innovation and Research (EMPIR). CFD modelling is used to analyse particle distributions in stacks with three different geometries of a supply pipe, different size of the particles and several concentrations. Vertical stack with a circular cross section of a diameter of 0.75 m is considered with the supply pipe containing none, one or two bends. The number of particles entering the stack defines the initial volumetric concentration from 0.1 to 10 mg/m³ with the particle size from 10 to 50 µm.Concentration fields in several cross-sections were compared and the particle distributions were analysed as functions of the physical conditions and the chosen geometry of the stack. The results show not very high sensitivity of the concentration profiles on the initial concentrations. On the other hand, significant changes of the concentration fields are observed when the stack geometry or the particle diameter is changed. This should be taken into account in the iso-kinetic sampling practise where the overall concentrations are calculated from measurements in several points.

The measurement of liquid film parameters is of great significance in the momentum transfer and heat transfer characteristics of gas-liquid two phase in annular flow. The liquid film at the bottom of the horizontal annular flow is the thickest and produces the greatest influence on the nature of the annular flow. In large diameter horizontal pipes, the effect of pressure on liquid film behavior lacks systematic discussion. Therefore, a dynamic measurement system for annular flow liquid film was designed based on near-infrared(NIR) sensing technology to complete the measurement of annular flow liquid film thickness data under five pressures. The average liquid film thickness at the bottom is obtained by variational modal decomposition(VMD) of the time series signal, and the wave velocity parameter is obtained by mutual correlation velocimetry. The article initially discusses the effect of pressure on the average thickness of the bottom liquid film as well as the interfacial wave velocity.