气液混输悬链线立管系统两相流特性实验

严重段塞流是海洋工程气液混输管线--立管系统中常见的一种特殊有害流动现象, 采用水平--下倾--悬链线立管气液混输组合管道系统, 通过系列实验在悬链线立管中获得了严重段塞流、间歇流和震荡流等流型, 阐述了这些流动现象的形成机理, 提出了能够产生严重段塞流的判定准则. 结果表明, 悬链线立管严重段塞流具有明显周期性, 在一个周期内的流动特征可分为液塞形成、液体出流、液气喷发及液体回流等4个阶段, 进而给出了各阶段中相关流动参数的变化规律. 在实验中同时还对悬链线与垂直立管中严重段塞流形成机理进行了比较分析, 发现两者在液塞形成阶段有显著差别. 其中, 在悬链线立管中液塞形成之前首先需要经历一个气液混合液塞形成过程, 而垂直立管则没有这个过程. 

Experiments on two-phase flow characteristics in a catenary riser system with the gas and liquid mixture transportation

Severe slugging is an undesirable flow phenomenon for a pipline-riser system with the gas-liquid mixture transportation in ocean engineering. In present paper experiments were performed for the two-phase flow characteristics in a horizontal/ declination pipeline-catenary riser system with the gas-liquid mixture transportation, and flow patterns were identified by series combinations of gas and liquid superficial velocities, including severe slug, intermittent and oscillation flows. The formation mechanisms of these flow patterns were presented and the conditions where the severe slug flow can be produced in the catenary riser were obtained. The results show that the severe slug flow in a catenary riser has remarkably periodic characteristics and consists of four stages in a circle, including slug formation, slug production, slug blowout and liquid fallback, respectively, where the characteristics of the flow parameters in each stage were given. Moreover, the formation mechanisms of severe slug flows in both catenary and vertical risers were compared and analyzed, and a remarkable differentiation in the slug formation stages for the two types of risers was observed, where the formation procedure of a mixture liquid slug with both gas and liquid first occurs before the pure liquid slug in the catenary riser can be produced, however, there is no occurrence of such a procedure of the mixture liquid slug for the vertical riser.