Numerical Simulation And Experimental Study Of Power-law Fluid

On this paper, numerical simulation and experimental study of power-law laminar and turbulent flow are basing on a high-resolution code. The governing equations of power-law fluid are deduced according to Newtonian NS equations. A high-resolution code of SIMPLE method is established based on FVM. The finite volume procedure is tested by calculating two laminar flows of power-law fluids, in a pipe and in an axisymmetric expansion, respectively. Three typical turbulent examples are used to assess five low Reynolds number κ-ε models in this paper before the study of modified low Reynolds numberκ-εmodels for power-law fluid.In experiment, wall pressure fluctuations for a square-sectioned90°bend turbulent flows are obtained by high sensitivity sensors.According to simulation it is observed that,the numerical results of power-law laminar flow in pipe and axisymmetric expansion take great agreement with experiment data and analytical solutions. A strategy of limiting the range of apparent viscosity is proposed successfully to avoid the singularities of viscosity at zero-and infinite shear rates. In the five low Reynolds number κ-ε models,the simulation of Newtonian pipe flows by NH model and LB model are good. But LB model takes poor results in backward facing step flow. According to the simulation consequence in pipe、U-channel and backward facing step,the NH model was better than other four low Reynolds κ-ε models.The results of power-law turbulent flow in pipe with modified LB model is good, and the new stress model based on NH model takes poor agreement with experiment data because of no power-law modification.The experimental data show that wall pressure fluctuations of0.1%CMC solution is nonuniform in different sections.The spectra of fluctuating wall pressures show the Multi scale characteristics of pseudoplastic liquids.