A novel investigation of a micropolar fluid characterized by nonlinear constitutive diffusion model in boundary layer flow and heat transfer.
The rheological and heat-conduction constitutive models of micropolar fluids (MFs), which are important non-Newtonian fluids, have been, until now, characterized by simple linear expressions, and as a consequence, the non-Newtonian performance of such fluids could not be effectively captured. Here, we establish the novel nonlinear constitutive models of a micropolar fluid and apply them to boundary layer flow and heat transfer problems. The nonlinear power law function of angular velocity is represented in the new models by employing generalized "n-diffusion theory," which has successfully described the characteristics of non-Newtonian fluids, such as shear-thinning and shear-thickening fluids. These novel models may offer a new approach to the theoretical understanding of shear-thinning behavior and anomalous heat transfer caused by the collective micro-rotation effects in a MF with shear flow according to recent experiments. The nonlinear similarity equations with a power law form are derived and the approximate analytical solutions are obtained by the homotopy analysis method, which is in good agreement with the numerical solutions. The results indicate that non-Newtonian behaviors involving a MF depend substantially on the power exponentnand the modified material parameter [Formula: see text] introduced by us. Furthermore, the relations of the engineering interest parameters, including local boundary layer thickness, local skin friction, and Nusselt number are found to be fitted by a quadratic polynomial tonwith high precision, which enables the extraction of the rapid predictions from a complex nonlinear boundary-layer transport system.
School of Energy and Environmental Engineering, University of Science and Technology Beijing , Beijing 100083, China.
Jize
0000-0002-0411-7930
J
Sui
School of Chemistry, Beijing Normal University , Beijing 100875, China.
Peng
P
Zhao
Artie McFerrin Department of Chemical Engineering, Texas A&M University , College Station, Texas 77843, USA.
Zhengdong
Z
Cheng
School of Mathematics and Physics, University of Science and Technology Beijing , Beijing 100083, China.
Liancun
L
Zheng
School of Mathematics and Physics, University of Science and Technology Beijing , Beijing 100083, China.
Xinxin
X
Zhang