Numerical simulation study of nozzle bench mark axial velocity before sudden expansion using computational fluid dynamics

Food and drug administration (FDA) benchmark study for biomedical flow transition. An idealized medical device is presented and CFD predictions of pressure and velocity are compared against experimental measurements of pressure and velocity. The fluid flow transitions considered laminar (Re=500), transitional (Re =2000), and turbulent (Re=6500) with various turbulence fluid flow simulation models of laminar, k-omega, k-omega SST and k-epsilon based on inlet throat Reth. = 500, 2000 and 6500. Axial velocity at centreline for Reth = 500, 2000 and 6500 at line X =0, showed maximum difference of 77.4% for velocity at centerline at 0.08m and 19% for wall pressure at -0.09m sudden expansion at laminar region of Re = 500. Good agreement with simulation happened at 65.6% and 17.2% transition Re =2000. At turbulent region Re = 6500, all models were in good agreement at 49.6% velocity centerline and 8.10% pressure drop, But in laminar legion, downstream of the simulation of Reth =6500, other models disappeared which demonstrated K-epsilon model is best at higher Reynolds turbulent region. Emphatically, from 0 to -120N/m2 counterbalanced at Reth = 500 wall pressure showed negligible axial pressure gradient at centerline with drop in normalization point of experimental data.