International Journal of Fluid Power Engineering, ISSN:2051-0732, Vol.20, Issue.1 1139 © RECENT SCIENCE PUBLICATIONS ARCHIVES| February 2014|$25.00 | 27703043 | *This article is authorized for use only by Recent Science Journal Authors, Subscribers and Partnering Institutions* Influence of Expansion Ratio of Varied Inclined Sudden Expansion Step on Hydrodynamics of Non- Newtonian Fluids Flow Khudheyer S. Mushatet College of Engineering, Thiqar University, Nassiriya, Iraq Email: khudheyer2004@yahoo.com Qais A. Rishak College of Engineering, Basra University, Basra, Iraq Email: qais_abd200@yahoo.com Sarah E. Hamdi College of Engineering, Thiqar University, Nassiriya, Iraq Email: msc_sara_emad@yahoo.com ABSTRACT A numerical study has been obtained to investigate the effect of a channel expansion ratio of varied inclined step on hydrodynamics behavior of the non-Newtonian fluids flow. The study covered a range of parameters such step angle of inclination (   90 30    ) and Prandtle number (2.5≤ Pr≤ 15) for Re=200. A Fluent software was used to get the solution of the governing equations while the mesh was created by using Gambit 2.3. The conducted results show that the size and strength of recirculation for shear thinning fluids is increased as expansion ratio increases and this trend is reflected for shear thickening fluids. Keywords-non-Newtonian fluids, sudden expansion, laminar flow 1. INTRODUCTION Investigation of non-Newtonian fluids flow in a sudden expansion is still represent one of the target issues for many researchers in recent years. The flow in such configuration is considered complex because the variable viscosity needs a suitable treatment models. Many devices uses the non-Newtonian fluids flow as polymers and manufacturing of coated sheets. The author here is still develop here an a sudden varied inclined step configuration by investigating the effect of its expansion ratio on hydrodynamics performance of non-Newtonian fluid flow. Many researchers studied the Newtonian and non-Newtonian fluid flow in a sudden expansion. Hawa and Rusak [1] studied numerically the dynamics of the incompressible laminar flow in a symmetric long channel with a sudden expansion. The results showed that the bifurcation at critical Reynolds number has a pitchfork nature and grew in parabolic manner near the critical Reynolds number. Pinho et al. [2] investigated the non- Newtonian fluid flow inside an axi symmetric sudden expansion channel. The shear thinning and inelastic with a viscosity obeying the power law model were used. They showed that at low Reynolds number, the local loss coefficient enhanced by more than 100٪ while it was enhanced by more than 50٪ at higher Reynolds number. Thiruvengadam et al.[3] investigated the laminar three dimensional Newtonian flow in a duct with expansion ratio 2 and aspect ratio of 4. It was found that the bifurcation induced due to the critical Reynolds number made the heat transfer and temperature distribution to be a symmetric in the transverse direction. An experimental study on the effect of three dimensionality on low Reynolds number flows past a symmetric sudden expansion channel was performed by Battaglia and Papadopoulos [4]. It was found that that the two dimensional numerical simulation failed to capture the effect of the expansion when the geometry was defined by the expansion ratio only. The laminar incompressible non- Newtonian fluids flow through a sudden expansion channel was studied by Manica and Bortelli [5]. The obtained results verified that the bifurcation was appeared after that of the Newtonian situation for shear-thinning and the opposite occurs for shear thickening.. The bifurcation phenomena in a two dimensional symmetric sudden expansion for different values of Reynolds numbers and expansion ratios was studied by Drikakis as cited by Nabavi [6]. It was noticed that the flow tendency to be asymmetric was increased with increasing the value of Reynolds number while it was decreased with increasing the value of expansion ratio. Ternik [7] investigated numerically the steady laminar flow of shear-thickening fluid in a 1:3 symmetric sudden expansion channel. The obtained results showed that the shear thickening trend lowers the thresh hold of the transition from flow symmetry to flow asymmetry. Alves et al. [8] made a numerical study to investigate the three dimensional non- Newtonian fluids flow in a square sudden contraction. Their results showed that the increase in the flow rate resulted multiple flow parameters depending on the studied fluids besides to the Deborah number. Chiang et al. [9] investigated the side wall effect on fluid down stream of a planar sudden expansion for different aspect ratios. They verified that the symmetry state was obtained at AR< 3.5 and Re=60 and the flow symmetry beyond this value was disappeared due to conda effect. Kalaf et al[10] studied the bifurcation phenomena in a sudden expansion channel of expansion ratio 1:3. They used a power law model along with a finite volume method to discretize the governing equations. The results verified that the non- Newtonian fluids behavior was similar to that of Newtonian fluids beyond the critical Reynolds number. In this study, a numerical investigation has been conducted to state the impact of expansion ratio on hydrodynamics of non-Newtonian fluids flow for varied inclined sudden expansion step. This study is performed