液-液旋流器内近壁湍流处理方法及数值模拟

Numerical simulation of the wall region of turbulence flow in the liquid-liquid hydrocyclone (LLHC)

无论k-ε模型及其修正模型,还是广泛应用于水力旋流器数值模拟的雷诺应力模型(RSM),都只是针对湍流核心区,对近壁区无效,如何确定液-液水力旋流器湍流场模拟的近壁处理方法亟待深入研究。在介绍湍流近壁区流动特点和处理方法的基础上,引入了2种湍流近壁处理函数——标准的和非平衡的壁面函数,在相同的网格系统和计算条件下计算了双锥双柱型水力旋流器内湍流场,结果与激光多普勒测速仪(LDV)测试结果基本吻合,但采用非平衡的壁面函数预报结果更为可信,为进一步精确研究旋流器内的流动过程打下良好的基础。

No matter the k-ε model or RSM used in hydrocyclone simulation, they both focused on the turbulence core and are invalid in near-wall region. Determination of the near-wall treatment approach for simulating the turbulence field in the hydrocyclone was deserved to further research. Based on an introduction of the characteristics of near-wall flow and the treatment approaches, a double-cone hydrocyclone was simulated under the same boundary conditions using RSM and different models of near-wall treatment. The prediction results showed good coincidence with result of LDV test. However, prediction results based on the non-equilibrium wall function is more reasonable and reliable through further comparison and analysis. The results had provided the foundation for future research of flow and separation process in LLHC.