Ω涡识别方法在双进口两级中开泵中的应用

为了研究双进口两级中开泵内部流动的涡旋特性,基于SST k-ω湍流模型,采用非定常数值计算方法,通过外特性试验和GCI准则验证了数值计算方法的合理性,并引入新一代涡识别方法Omega(Ω)法,对其内流场中的涡旋结构进行分析.研究结果表明:传统的涡识别方法不能有效剔除壁面剪切层的影响,而Ω方法能将流体的剪切和纯旋转运动进行区分,获得较为清晰的泵内涡旋结构,特别是在两级叶轮中,能准确捕捉到尾迹涡的形态和分布情况;在不同工况下,将三维的Ω涡识别方法简化到二维平面后,其在反流道中的适应性更好,规避了之前许多没有形成涡旋结构而流线呈现出强扭曲的区域,同时证明了轴向涡旋在反流道中占主导地位.另外,研究过程证明了Ω方法在双进口两级中开泵这种复杂流体机械内部涡旋结构的识别中具有较大的优势,可以为该型泵进一步的设计优化提供相关理论依据.

Application of the Ω vortex identification method in a two-stage double-suction centrifugal pump

In order to study the vortex characteristics of internal flow inside the two-stage double-suction centrifugal pump, the unsteady numerical simulation method based on the SST k-ω turbulence model was adopted. The rationality of the numerical calculation method is verified by the performance test and GCI criterion. A new generation vortex identification method—Ω method is introduced to analyze the vortex structure in its internal flow field. The results showed that the traditional vortex identification method cannot effectively eliminate the influence of wall shear layer, while the Ω method can distinguish the shear and pure rotational motion of the fluid, and obtain a clearer vortex structure in the pump, especially in the two-stage impeller, which can accurately capture the morphology and distribution of the wake vortex. Under different working conditions, after simplifying the three-dimensional Ω vortex identification method to the two-dimensional plane, it has better adaptability in the back channel, and it circumvented many regions where the flow line showed strong distortion without forming vortex structures before, and it also proved that axial vortex structures is dominate in the back channel. In addition, the research process proved that the Ω method has a greater advantage in identifying the internal vortex structure of complex fluid machinery such as a two-stage double-suction centrifugal pump, which can provide a relevant theoretical basis for further design optimization of this type of pump.