幂律流体在圆管内湍流流动剪切率的近似计算

An estimation approach to the shear rate of the power law fluid in turbulent pipe flow

根据剪切率和能量耗散率的定义 ,建立了幂律流体湍流剪切率与能量耗散率的关系式。参照文献上对不可压缩牛顿流体湍流能量耗散率的近似算法 ,提出了一种幂律流体管内湍流能量耗散率的近似算法 ,从而得到了幂律流体管内湍流剪切率的实用近似算式 ,再利用湍流剪切率与脉动流剪切率的关系即可得到脉动流剪切率。

According to the definition, a relationship between the shear rate and the energy dissipation rate is obtained for turbulent flow of power law fluid. By imitating the approach to approximately estimating the turbulent energy dissipation rate for incompressible Newtonian fluid, an approximate calculation method is developed for the turbulent energy dissipation rate for the pipe flow of the power law fluid, thus a practical equation is obtained for estimation of the turbulent shear rate of the power law fluid. Therefore, shear rate due to velocity fluctuations can be determined by using its relationship with the turbulent shear rate. Characteristics of estimated turbulent shear rate and its variation with the power law index agree with known results.