油品脱水用碟式离心机的流场及分离性能

Flow Field and Separation Performance of Disc Centrifuge for Oil Dewatering

研究对象为油品脱水用碟式离心机,通过CFD模拟研究了碟式离心机碟片上螺旋型筋条对碟片间两相三维流动的影响规律。结果表明,同一径向位置上,相邻两碟片间液流的周向速度在平行于转轴的面内呈抛物线分布,接触碟片表面处流体跟随碟片旋转,远离碟片处流体的周向速度大于碟片的周向速度;螺旋型筋条能够有效地减小这种滞后性,而且能够有效地减小碟片间流动的湍流强度;不同碟片间的分散相体积分数分布不一,顶层和底层中的高,中间层内的低;同一碟片间,中性进料孔和定距筋条附近有水相浓集现象。螺旋型筋条能够有效地提高分散相分布的均匀性和分离效率,研究发现,螺旋型筋条的碟片结构能使碟式离心机实现航空煤油的高精度分离。

The research object of this paper is a disc centrifuge for oil products dewatering.CFD simulation is used to study the effects of helical ribbing on the three-dimensional flow between discs in the disc centrifuge.Simulation results show that,at the same radial position,the circumferential velocity of the liquid flow between two adjacent discs is parabolically distributed in the plane parallel to the rotating shaft.The fluid on the surfaces of discs is rotated with the discs.For the fluid far away from the disc,their circumferential velocity is greater than that of the disc.Not only can spiral ribs effectively reduce the above hysteresis,but also can effectively reduce the turbulent flow intensity between discs.It is also found that the concentration distribution of dispersed phase between layers is different,i.e.higher concentration in top and bottom layers,but lower concentration in the middle.It has been observed that water phase is concentrated in the neutral feed hole and near the ribs between the two discs.Spiral ribs can effectively improve the uniformity of the dispersed phase distribution and separation efficiency.The disc structure of the spiral ribs enables the disc centrifuge to achieve high-precision separation of aviation kerosene.