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Pipeline transportation of liquid CO2 can not only prevent coal mine fires, but also effectively store greenhouse gase CO2 in underground, which is in line with the current global economic development model. Due to the temperature difference of the mine environment and the inclination of the roadway, heat exchange and large pressure drop will inevitably occur in the pipeline. In order to avoid the phase change of liquid CO2 during transportation, it is necessary to consider factors such as ambient temperature, wind speed, insulation cotton, pipeline inclination, and terrain elevation to ensure safe, cost-effective transportation. Based on the commercial simulation software ASPEN HYSYS V8.4, this paper simulates the process of liquid CO2 transportation. The results show that the inclination of the pipeline has a great influence on the CO2 transportation process among environmental factors and is conducive to liquid CO2 transportation.

This article presents a computer vision-based approach for monitoring water flow at outlet points of a tile drain system. The approach relies only on video capture of events at outlet points, thus a camera can be installed remotely and without contact with water. The algorithm detects, identifies, and tracks flows by motion, shape, and color features and measures flow rate based on a proposed model and two provided dimensions. The software was tested in a laboratory environment with three different target flow rate conditions: 0.312, 0.946, and 1.58 L/s (5, 15, and 25 gal/min). Flow rates reported by the computer vision approach are within 12% of the ground-truth flow rate baseline. The results of this work show that computer vision can be used as a reliable method for monitoring outlet flows from free-standing outlet structures under laboratory conditions. This work opens the possibility of applying computer vision techniques in tile drain monitoring from outlet points with mobile video recording devices in the field. [ABSTRACT FROM AUTHOR]

Based on the rapidly varying casing pressure method and multiphase flow theory, we have constructed a transient mathematical model for managed pressure drilling (MPD) that combines kick with mud loss in a single fracture. The finite difference method was used to iteratively solve this model. The model calculated values agree well with the experimental results, which confirms the reliability of the model. Casing pressure, casing shoe pressure, pit gain, outlet flow, and choke opening during the entire well control process are analyzed. Experimental results show that equality of inlet flow and outlet flow may not imply influx stoppage when a kick is coupled with mud loss. In addition, the loss rate at the casing shoe initially increases linearly over time and then decreases exponentially, ultimately becoming constant. After completion of well control, drilling can be safely continued until loss is negligible. This study may provide a theoretical basis for better control of wells with complicated kick and circulation loss in managed pressure drilling (MPD). [ABSTRACT FROM AUTHOR]

This paper is a numerical study on the prediction of a cavitation bubble in the wake of an elasto-hydrodynamically lubricated ball-on-plate contact as observed in experiments at low velocity. A standard EHL-model is coupled with an elementary 2-phase pressure–density model, which yields a strong density decrease for sub-atmospheric pressures. A cavitation bubble can indeed be predicted, but its length is highly underpredicted when compared with available experimental results. Accurate prediction appears to call for more advanced fluid modeling, e.g. the physics of cavitation and aspects of 3D 2-phase flow. [ABSTRACT FROM AUTHOR]

3D hydrological modeling was performed, using CATHY (acronym for CATchment HYdrology model), with the basic objective of checking whether the model could reproduce the effects of subsurface agricultural drainage on stream flows and soil water storage. The model was also used to further our understanding of the impact of soil hydrodynamic properties on watershed hydrology. Flows simulated by CATHY were consistent with traditional subsurface drainage approaches and, for wet years, flows at the outlet of the study watershed corroborated well with observed data. Temporal storage variation analyses illustrated that flows depended not only on the amount of rainfall, but also on its distribution throughout the year. Subsurface agricultural drainage increased base and total flows, and decreased peak flows. Hydrograph separation using simulated results indicated that exfiltration was the most dominant process; peak flows were largely characterized by overland flow; and subsurface drain flow variations were low. [ABSTRACT FROM AUTHOR]

Air-driven boosters are widely used to obtain high-pressure gas. Through analysis of the boosting process of an air-driven booster, the basic mathematical model of working processes can be set up. By selecting the appropriate reference values, the basic mathematical model is transformed to a dimensionless expression. Using MATLAB/Simulink for simulation and studying the booster experimentally, the dimensionless outlet flow characteristics of the booster were obtained and the simulation results agree well with the experimental results. Through analysis, it can be seen that the dimensionless outlet flow of the booster is mainly determined by the dimensionless input pressure of the driving chamber, the dimensionless outlet condition pressure of the booster and the dimensionless area of the piston in the driving chamber. The dimensionless average outlet flow becomes larger with an increasing dimensionless input pressure of the driving chamber, but it becomes smaller with an increase in the dimensionless outlet condition pressure of the booster. Especially when the dimensionless outlet condition pressure is approximately 1.4, the dimensionless average outlet flow reaches zero. With an increase in the dimensionless area of the piston in the driving chamber, the dimensionless average outlet flow increases and peaks at approximately 1.89, and after this peak, it starts to decrease. This research can be referred to in the design of air-driven boosters. [ABSTRACT FROM AUTHOR]