卧螺离心机内压力场的数值模拟

Numerical simulation on pressure field in a decanter centrifuge

卧螺离心机在高浓度固液混合物分离领域中应用广泛,其内部结构复杂,且封闭高速运转,对其内部流场实时监测难度大,缺乏对其内部流场特性的了解,进而影响对其分离性能的研究。本文应用计算流体力学软件Fluent,采用RNG k-ε湍流模型多重参考系(MRF)方法,模拟分析了卧螺离心机的内部流场,得到了压力场分布情况。结果表明:模拟液压值与理论液压值之间存在着一个差值,该差值是由于液体转动的滞后造成,且随着转鼓转速的增大而增大。同时还发现,静压、动压均随着径向位置的增大而增大,且静压梯度比动压大;沿转鼓轴向即往排液口方向,静压有递减的趋势,而动压逐渐增大。这可为进一步深入研究卧螺离心机提供参考。

Decanter centrifuges have been widely used for the separation of solid-liquid mixtures with high solid concentration. The real-time monitoring of the flow field inside the centrifuge is believed to be difficult because of its complexity in structure and closed operation at high speed of rotation. RNG k-εturbulent model and MRF method based on the FLUENT software of computational fluid dynamic technology were used in this research to simulate the pressure field in the centrifuge. Results showed that the differences between simulated and theoretical hydraulic pressure caused by the lag of liquid rotation increased with increase in rotational speed. The static pressure and dynamical pressure increased with radius,and the gradient of static pressure was greater than that of dynamical pressure. The static pressure increased along the drum axis from the inlet to liquid discharge port,while the dynamical pressure decreased gradually. It could be used as guidance for researching the performance of decanter centrifuges.