In order to study the flow field of polyurethane low-pressure mixer and the influence of impeller's different structure to the species transport process in mixer,a unsteady species transport 3D numerical simulation was conducted by using computational fluid dynamics software Fluent,standard model,standard wall function and species transport equation (noreactions).The results indicate that fluid flow is in good condition,there is no obvious dead zone and the mixing time of species transport is 30 s.The mixing effectiveness is the best,when the impeller layers,impellers and impeller angel are 8,8 and 15 °,respectively.A species transport experiment was carried on to validate the reliability of simulation.A good agreement was obtained between the experimental data of acetone volume fraction and the simulation results in the flowfields of ethanol-acetone systems,and the maximum relative error was lower than 5％.This suggests that using CFD model to simulate and forecast the process of species transport is feasible and effective in the low-pressure mixer.%为探究聚氨酯低压混合器内流体流动状况以及不同混合头结构对混合器内组分输运过程的影响,利用流体力学软件Fluent,采用标准湍流模型和标准壁面函数,开启组分输运方程,不开启反应方程,对混合器内非稳态组分输运过程进行三维数值模拟.模拟结果表明:混合器内流体流动状况良好,无明显死区,混合器内组分输运过程混合时间为30s;当叶片层数为8、周向叶片数为8、叶片倾斜角为15°时,混合头的混合效果最好.为验证模拟的可靠性,对混合器内组分输运过程进行实验验证.结果显示:模拟结果与实验数据具有较高的吻合度,最大相对误差低于5％,这表明利用CFD模型对低压混合器内组分输运过程进行预测和模拟是可行的、有效的.
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