An Analysis of the Effectiveness of Flow Conditioners in Reducing Turbulent Kinetic Energy in Pulsatile Pipe Flow

Turbulent flow produces significant fluctuations in fluid dynamic properties including volumetric flow rate, wall shear stress, and pressure. Moreover, in benchtop experimental setups, the use of equipment such as gear pumps can induce undesired and unpredictable flow disturbances that can lead to inaccurate or inconsistent flow measurements. Thus, for such experiments, proper flow conditioning is critical, to ensure measurements are highly repeatable and initial conditions are consistent across test cases. While significant research has been conducted on flow conditioning in large-scale environments, few studies have investigated optimal conditioners for use in small-diameter (D < 2 inches) and pulsatile flows, often needed for in vitro hemodynamic studies. In this work, we compare the performance of large-diameter flow conditioners (the Laws plate, Etoile, and tube bundle) at reducing the turbulent kinetic energy (TKE) in small-diameter, physiologically-relevant flows. We use both planar particle image velocimetry (PIV) and computational fluid dynamic (CFD) to evaluate the TKE upstream, within, and at several locations downstream of the flow conditioners. Reduction of TKE as well as the induced pressure drop were used to evaluate the efficacy of each flow conditioner tested.