二次流实现流体混沌混合的数值研究

在加权残余法与谱方法相结合的基础上,分析了扭转弯管中的二次层流,并说明了在某些情况下将诱发混沌现象.根据二次流的动力学特性,建立了扭管不同截面之间的非线性映射关系,用数值方法研究了流体微团在该映射下的混合特性,并进行了实验研究.结果表明,利用不同的单元弯管的组合与连续扭转,可以实现流体在层流状态下的高效无切割混合.

NUMERICAL STUDY ON CHAOTIC MIXING CAUSED BY SECONDARY FLOW

The secondary flow in a twisted curved pipe is studied by using Gelarkin method together with spectral method, and the secondary approximating solution of the velocity profile in the cross - section is given. Based on this velocity profile, the nonlinear mapping between the cross-sections is studied by numerical integration. It is found that the periodic pair-vortex induced from the secondary flow resulted in a chaotic mapping, which stretch and fold the fluid units in an exponential way, and mix the fluid in the pipe efficiently. The result is displayed by numerical simulation and experimental study.