舟山LNG取水泵站泥沙减淤清淤试验研究

Experimental study on sediment reduction and dredging at Zhoushan LNG intake pump station

LNG接收站取水流道内水流形态复杂,泥沙淤积问题往往难以避免,特别是在含沙量较高水域,流道内泥沙淤积可能威胁接收站的正常运营。为实现LNG取水泵站不停机条件下清淤,开展取水泵站射流冲刷物理模型试验,模拟了射流冲沙装置开启后吸水间射流水流特征及冲刷效果,探究了射流冲刷设置的喷嘴与翼墙夹角、射流流量、冲刷时间等因素影响下流道内减淤清淤效果。试验结果表明,在理想状态下吸水间射流冲沙装置连续作用12h基本可达到较为理想的清淤效果;一次大风浪过后,装置连续作用0.5h基本可达到较为理想的清淤效果。清淤效果视射流流量、喷嘴与翼墙夹角以及冲刷时间不同而有差别。结合取水泵站泥沙淤积物理模型试验研究成果,取水泵站淤积区主要发生在前池、过滤池末端、吸水间和消防泵附近,建议在这些区域安装射流冲沙装置,实现不停机状态下的减淤清淤,提高取水安全保证率,从而提高运营效益。

The water flow in the LNG receiving station’s water intake channel is complex,and sedimentation issues are often unavoidable,especially in areas with high sediment content.Sedimentation within the channel may pose a threat to the normal operation of the receiving station.To achieve dredging without stopping the operation of the LNG intake pump station,a physical model experiment of jet flushing was conducted.The experiment simulated the characteristics of the water flow between suction intervals and the flushing effect after the jet flushing device was activated.It explored the impact of factors such as the angle between the nozzle and the wing wall,jet flow rate,and flushing time on the sediment reduction and dredging effect within the channel.The results indicate that under ideal conditions,continuous operation of the jet flushing device for 12 h can achieve a relatively ideal dredging effect.After a single large wave,the device’s continuous operation for half an hour can also achieve a relatively ideal dredging effect.The dredging effect varies with different jet flow rates,nozzle and wing wall angles,and flushing times.Combining the results of the physical model experiment on sedimentation at the intake pump station,sedimentation mainly occurs in the forebay,end of the filtration pool,suction intervals,and near the firefighting pump.It is recommended to install jet flushing devices in these areas to achieve sediment reduction and dredging without stopping the operation,improving water intake safety assurance,and enhancing operational efficiency.