Flow patterns and shear stress distributions were investigated in a doublelumen cannula. Pressure and flow rate were measured on a steady-flow rig by imposing 6 KPa and 12 KPa pressure drop across the drainage and infusion lumen, respectively (flow rate about 2 L/min). The fluid was modeled as newtonian with density and dynamic viscosity equal to 1050 Kg/m3 and 0,0035 Kg/ m/s, respectively. The numerical results well predicted the global performances of the cannula, thus allowing to evaluate the incidence of geometry on the hemolytic potential. The simulations were performed in a transitional flow regimen. The 3D RANS equations were considered using the “transitional” version of the standard k-w turbulence model. The discretization of the governing equations was based on a cell-centered finite volume method. For the drainage lumen, shear stress peak values (326 Pa), mainly due to presence of side holes, have been computed. Lower peak values (213 Pa) were computed for the infusion lumen in proximity of the outlet section. In both cases, shear stress levels were lower than the hemolysis threshold: 400–600 Pa.
Numerical and Experimental flow analysis of the Wang-Zwische double-lumen cannula
DE BARTOLO, CARMINE;FRAGOMENI G;DE NAPOLI, Luigi;DANIELI G;
2009-01-01
Abstract
Flow patterns and shear stress distributions were investigated in a doublelumen cannula. Pressure and flow rate were measured on a steady-flow rig by imposing 6 KPa and 12 KPa pressure drop across the drainage and infusion lumen, respectively (flow rate about 2 L/min). The fluid was modeled as newtonian with density and dynamic viscosity equal to 1050 Kg/m3 and 0,0035 Kg/ m/s, respectively. The numerical results well predicted the global performances of the cannula, thus allowing to evaluate the incidence of geometry on the hemolytic potential. The simulations were performed in a transitional flow regimen. The 3D RANS equations were considered using the “transitional” version of the standard k-w turbulence model. The discretization of the governing equations was based on a cell-centered finite volume method. For the drainage lumen, shear stress peak values (326 Pa), mainly due to presence of side holes, have been computed. Lower peak values (213 Pa) were computed for the infusion lumen in proximity of the outlet section. In both cases, shear stress levels were lower than the hemolysis threshold: 400–600 Pa.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
