In offshore oil and gas transport, gas-liquid mixed transport is a basic flow phenomenon. In general, pipeline undulations are caused by seabed topography; therefore, it is of great significance to study the mechanisms underlying gas and liquid flows in hilly-terrain pipeline-riser systems. This study established a hilly-terrain pipeline-riser experimental system in an indoor laboratory. The flow pattern and its flow mechanism were studied via experimental observation and pressure detection. Experimental results showed that the gas-liquid flow pattern in the hilly-terrain pipeline-riser system can be divided into four types: severe slugging, dual-peak slug, oscillation flow, and stable flow, where dual-peak slug flow is a special flow pattern in this pipeline system. Hilly-terrain units obstruct the downstream gas transport, weaken the gas-liquid eruption in the riser, and increase the cycle of severe slugging. In this paper, gas is regarded as power in the flow of gas and liquid, and the accumulation of liquid in low-lying areas is regarded as an obstacle. Then, the moment of gas-liquid blowout is studied as main research object, and the mechanism of flow pattern transformation is described in detail. This study investigated the accuracy of the OLGA 7.0 simulation results for the gas-liquid two-phase flow in the hilly-terrain pipeline-riser. The results show that OLGA 7.0 achieves a more accurate calculation of severe slugging and stable flow and can predict both the pressure trend and change characteristics. However, the simulation accuracies for dual-peak slug flow and oscillation flow are poor, and the sensitivity to gas changes is insufficient.
This paper focuses on the maintenance of automotive stamping automation equipment. Through long-term self-study and accumulated experience, we independently developed a process monitoring system based on the three pumping stations of clutch, tension pad and lubrication in the stamping automation production line, which is used for real-time monitoring and diagnosis in the automatic production process without stopping the machine, and for the detection of oil temperature change, high-pressure pipeline leakage and oil return pipe In this paper, the improved case has strong practicability, low development cost, and has been recognized by peers in terms of cost efficiency improvement, which is easy to be popularized.
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