چكيده به لاتين
Because of Iran's oil production high value, financial losses due to inaccuracy in measuring could be significant. Therefore, in this study, by studying and reviewing numerous literature, the most recent methods of accurate measurement of multi phase flows are introduced, among which, the cross-correlation ultrasonic flow meter, due to high accuracy, uninterrupted measurement, easy installation, low cost and also the clamp-on installation is becoming the first option for measuring the multi-phase flows. Cross correlation flow meters, like other types of flow meters in the industry, requires calibration and debugging in various operating conditions. Therefore, the purpose of this study is to simulate the cross-correlation ultrasonic flow meter and calculating correction factor in different operational conditions. Also, in this investigation, the most important operational parameters affecting the flow meter performance are introduced and the effect of each one are investigated. The most important parameters affecting the flow meter performance and the correction factor, according to studies and surveys, are the distance between the two sensors, the length of the direct pipe before the meter, the operating pressure of the system, the pattern of flow and roughness of the tube surface. Using CFD simulation and applying turbulent kinetic energy, turbulent dissipation rate and axial flow velocity in meter model presented in the literature, the flow rate of the meter and its correction factor were calculated for two phase flow air-water in range of Reynolds number from 0.07 to 0.19 million with stratified and bubbly flow patterns. The results were validated with maximum of 2% errors compared to the data presented in the literature. Also, it was found that the correction factor changes in range of Reynolds number 0.86 to 0.9 which shows relative accuracy of flow meter. Also, CFD shows that with increasing distance between the two sensors, reducing the length of the direct pipe before the meter, increasing the surface roughness of the pipe and increasing the operating pressure, the accuracy of the meter decreases and the flow correction factor increases. Furthermore, it was found that correction factor depends on two phase flow pattern and sensor array on pipe.
