水平分支型集输管汇偏流程度数值模拟研究

Numerical simulation on the flow maldistribution degree of horizontal branched gathering manifolds

以水平分支型集输管汇为研究对象,选用FLUENT作为模拟软件分析了管汇入口来流气相折算速度、液相折算速度对水平双出口与水平四出口管汇偏流程度的影响规律,并开展了水平双出口分支型管汇偏流敏感性分析。结果表明,如果管汇几何结构完全对称且各出口压力相同,那么双出口管汇内各分支管的流量将会均匀分配,而四出口管汇则会出现偏流。2个分支管长度存在较小偏差对水平双出口分支型管汇偏流的影响可以忽略不计;实际生产中双出口分支型管汇偏流的主要原因为各分支管出口压力不一致和当量管径不一致,当两个分支管出口压力偏差恒定时,存在着决定管汇偏流严重程度的临界气液比;若来流气液比小于该临界值,则管汇偏流程度通常在可接受范围内。为控制由分支管管径偏差引起的偏流,建议首先可以考虑调节来流气液比,其次考虑清管处理。本文研究成果可为控制集输管汇偏流程度提供依据。

Taking horizontal branched gathering manifolds as the research object,this paper uses FLUENT software to analyze the influences of the superficial gas velocity and the superficial liquid velocity at the manifold inlet on the flow maldistribution degree of the manifolds with two outlets and four outlets,respectively.Moreover,a sensitivity analysis of the horizontal manifold with two outlets is carried out.Simulation results show that if the manifold geometry is fully symmetrical and the pressure of every outlet is equal,the fluid in the manifold with two outlets will be evenly distributed among each outlet,and the manifold with four outlets will experience a flow maldistribution.The minor deviation of the length of the two branch pipes has a negligible effect on the flow maldistribution of the manifold with two outlets.In field production,the inconsistency between the pressure and the equivalent diameter of the two outlets cause the flow maldistribution of a branched gathering manifold.For a constant deviation of the outlet pressure,the flow maldistribution degree is determined by the critical gas-liquid ratio.When the gas-liquid ratio is lower than the critical valve,the flow maldistribution degree is usually acceptable.For controlling the flow maldistribution caused by the deviation of the diameters of branch pipes,the gas-liquid ratio should be firstly adjusted and then the pigging process should be implemented.The results in this paper can provide a reference for control the flow maldistribution degree of gathering manifolds.