The term rheology has a great impact on the velocity profile of a fluid flow by linking the shear stresses and shear rates in a control volume. Despite this relationship is being proportional in many fluids in the industry called Newtonian type, most of the fluids we interact with within our daily lives have non-Newtonian characteristics showing non-proportional relation. For instance, human blood, petrol, some medical mixtures, paint, toothpaste, shampoo, etc. Such fluids having non-Newtonian characteristics means that their rheology is a variable especially at the interactions with physical contiguities, such as wall boundaries. In the present study, the modeled non-Newtonian fluid fits the Herschel Bulkley model that includes the yield stress and shear thinning behavior. Therefore, a fluid having yield stress causes a region with no shear rate called plug flow in the control volume where the local shear stresses are below the yield stress. The CFD solution of a non-Newtonian fluid requires special treatment on both the Momentum equation and the rheology expression. This work covers a laminar flow analysis of a non-Newtonian fluid realized by a developed in-house CFD code. As a result, the work obtained the velocity profile and pressure distribution along the 2D parallel plate control volume through the inclusion of the Herschel Bulkley rheology model to the momentum equations. A concordance was observed between the velocity and pressure distributions obtained with different discretization schemes. This study is derived from the works of the authors Master thesis.
Anahtar Kelimeler: Herschel Bulkley, non-Newtonian, Parallel plates, CFD modeling