基于分形桨的湍流耗散强度特征研究

Characteristics analysis of turbulent energy dissipation intensity based on fractal impellers

针对搅拌过程中湍能耗散造成的能量损失问题,提出了一类新型分形几何涡轮桨,并基于计算流体动力学,对系列分形桨进行湍能耗散强度分布数值模拟实验。通过分析分形桨的湍能耗散分布强度规律,探究了分形维数及迭代次数对搅拌设备各部分湍能耗散以及搅拌功率的影响。结果表明:流场湍能耗散强度分布特征为横向呈风轮状,纵向呈扇状;相对于无迭代桨,分形迭代桨湍流耗散强度降低;分形维数增加会降低各处的湍能耗散强度。迭代次数增加会降低流场中湍能耗散,但会增大搅拌桨上的耗散强度;分形迭代桨会降低搅拌功率,并随着分形维数增大而效果加强。研究结果为高速离心搅拌桨设计提供新的设计思路。

Aim to the energy loss caused by turbulent energy dissipation in high-speed centrifugal mixing processes, a new type of impellers with fractal geometry was proposed. Based on the computational fluid dynamics, the intensity distribution numerical simulations of turbulent energy dissipation was carried out for the series of fractal impellers. By analyzing the intensity law of turbulent energy dissipation distribution of the fractal Impellers, the effect of fractal dimension and number of iterations on the turbulent energy dissipation in each part of the mixing equipment and on the stirring power was investigated. The results show that the turbulent energy dissipation intensity distribution of the flow field has a wind-wheel shape in the transverse direction and a fan shape in the longitudinal direction. Compared to non-iterated impeller, the fractal iterative impellers reduce turbulent energy dissipation intensity. Increasing the fractal dimension can improve the turbulent energy dissipation intensity at each part. Increasing the number of iterations can reduce the turbulent energy dissipation in the flow field, but improve the dissipation intensity on the stirring impellers. The fractal iterative impellers reduce the stirring power, and the effect is enhanced as the fractal dimension increasing. The results of the study can provide new design references for high-speed centrifugal stirring impellers design.