Flow measurements that utilize differential pressure meters are commonly applied in industry. In such conditions, gas flow is often accompanied by liquid condensation. For this reason, errors occur in the metering process that can be attributed to the fluctuations in continuous phase parameters in the flow. Furthermore, the occurrence of a dispersed phase results in flow disturbance and dynamic pressure pulsations. For the above reasons, new methods and tools are sought with the purpose of performing measurements of gas-liquid flows providing measurement results that can be considered as fairly accurate in the cases when flow involves a liquid phase form. The paper reports the results of a study involving measurement of wet gas flow using differential pressure flowmeters. The experiments were conducted for three constant mass air flow rates equal to 0.06, 0.078 and 0.086 kg/s. After stabilization of the air flow rates, water was fed into the pipe with flow rates in the range from 0.01 to 0.16 kg/s. The research involved a standard orifice and three types of slotted orifices with various slot arrangements and geometries. The analysis focused on the effect of orifice geometry on the flow metering results. On the basis of the results, it was found that the slotted orifice generates smaller differential pressure values compared to the standard orifice. The water mass fraction in the gas leads to overestimated results of measurements across the flowmeter. Regardless of the type of the orifice, is necessary to undertake a correction of the results. The paper proposes a method of gas mass flow correction. The results were compared with the common over-reading correction models available in the literature.

The article presents the results of flow investigations downstream of a standard and slotted orifice plate, obtained using both experimental measurements with the Particle Image Velocimetry (PIV) method and numerical calculations performed in a CFD environment. The aim of the study was a detailed analysis of the velocity field structure and an evaluation of the prediction accuracy of different turbulence models in relation to experimental data. The study employed models from the k-ε and k-ω groups, which were compared in terms of their agreement with measurement results in various flow regions. The study demonstrated that no single turbulence model guarantees optimal results across the entire investigated domain. Model selection should therefore be adapted to the analyzed flow region k-ω models in the vicinity of the orifice and k-ε models in the developed flow region. The findings have significant practical implications for the engineering of orifice flow meters, enabling a more informed use of CFD methods in the design and validation of industrial measurement systems.

The differential pressure of gas measurement is very often used in industrial measurements. During the gas flow, liquid condensation often occurs. The result is that when measuring a gas flow, the gas-liquid mixture is essentially measured. Errors in the indications of measuring instruments are starting to appear due to a change in the properties of the continuous phase, which is gas. In addition, the appearance of liquid droplets leads to flow disturbances and pressure pulsations. Therefore, new methods and tools for measuring the flow of gas-liquid mixture are being sought. The work involves the use of slotted orifices for measuring gas-liquid mixtures. An analysis of the influence of the slotted orifice geometry on the measurement of the biphasic mixture stream was carried out. Standard orifice and three slotted orifices of various designs. The experiment included measuring the air flow with a small amount of water dispersed in the form of drops.

The paper presents the results of simulation studies of fluid flow through a standard orifice and two slotted orifices. The research that has been carried out concerns the analysis of the effect of the orifice geometry on the velocity profiles, turbulence kinetic energy and turbulence energy dispersion. The profile studies were conducted at different distances behind the orifice so that the results could be compared with each other. The studied flow included an airflow whose inlet velocity was 15 m/s. The turbulence model k-ε was used for numerical calculations. The tested orifices were characterized by an orifice constriction equal to β = 0.5. The calculations involved flow through a pipeline with a diameter of 160 mm. The results show that for a standard orifice, the maximum velocity of the flow is about 95 m/s and this is recorded at a distance of about 10–20 cm behind the orifice, and then it decreases, and at a distance of about 60 cm, the flow velocity is about 27 m/s. In the case of slotted holes, the maximum velocity is about 30% lower compared to the flow rate through a standard orifice design. The maximum velocity behind slotted orifices occurs directly behind the orifice, and in the cases of slotted orifice 1 and slotted orifice 2, was about 70 m/s and 67 m/s, respectively. For slotted orifice 1, at a distance of 20 cm behind the orifice, the flow assumed a velocity of about 19 m/s, whereas for slotted orifice 2, the flow reached a speed of about 18 m/s, at a distance of about 30 cm behind the orifice. The values of the maximum kinetic energy of turbulence for the tested orifices are about 420 m²/s² for the standard orifice, and about 250 m²/s² and 220 m²/s² for slotted orifices 1 and 2, respectively. The obtained simulation results demonstrated that slotted orifices lead to faster stream homogenization and do not disturb the flow as much as a standard orifice. Slotted orifices exhibit a higher flow coefficient.