弯管内成品油顺序输送混油数值计算

为了研究弯管对成品油顺序输送混油量的影响，采用volume of fluid（VOF）多相流模型，通过改变水平弯管的弯曲角度、曲率半径与竖直双弯管油品的输送顺序、方向及速度等因素，对水平弯管和竖直双弯管两种状态下成品油顺序输送进行三维数值模拟。结果表明：成品油在不同弯曲角度水平弯管中顺序输送时，随弯管弯曲角度增大，弯管处流场变化对混油段干扰加剧，混油量加大；在不同曲率半径水平弯管中输送时，随着弯管曲率半径增大，混油“双前锋”效应减弱，顺序输送过程中的混油段也相应缩短；成品油在竖直双弯管中顺序输送时，对于油品上行，汽油前行比柴油前行产生的混油量少，对于油品下行，相同输送顺序下结果则正好相反；当油品上行、汽油前行时，增大油品输送速度，紊流径向脉动加剧，油品间轴向扩散减小，混油段明显变短。

Numerical calculation for mixed oil in batch transportation at an elbow

In order to study the influence of an elbow pipe on the amount of refined oil mixed in sequential delivery, the volume of fluid (VOF) multi-phase flow model was adopted. By changing the bending angle of the horizontal elbow pipe, the radius of curvature and the delivery sequence of the vertical double elbow pipe, direction and speed, three-dimensional numerical simulations of the orderly delivery of refined oil under both horizontal and vertical double bends have been carried out. The results show that when the product oil is transported sequentially in different horizontal bending pipes with different bending angles, as the bending angle of the pipe increases, the variation of flow field at the bend increases the interference in the mixed oil section and the rate of mixing of the oil increases. When conveyed in horizontal bends with different radii of curvature, as the curvature radius of the elbow increases, the "double forward" effect of the mixed oil decreases and the mixed oil segment in the process of sequential delivery decreases accordingly. When the product oil is conveyed sequentially in a vertical double-bend pipe, for the oil to go up, the amount of the mixed oil produced by the gas oil forward is smaller than that from the diesel oil forward; for the oil to go down, the result is exactly opposite for the same sequence of delivery. When the oil goes up and the gas oil goes ahead, as the oil delivery speed increases, the radial pulsation of the turbulent flow is increased, the axial diffusion between the oil products decreases and the mixed oil section becomes significantly shorter.