Numerical Simulation of a Pulsating Flow Generated in an Ejector

Abstract

SummaryThis paper presents a numerical simulation of a pulsating flow generated inside an ejector; the flow is intended to oxidize ferrous iron (Fe 2+ ) dissolved in drinking water to ferric iron (Fe 3+ ). The pulsating flow ejector can be used in water treatment systems where the water is saturated with oxygen before being treated by filters. It is shown that the pulsating flow is generated due to fluctuations in the pressure, density, and velocity of the flow inside the ejector. It is established that the flow pressure inside the ejector varies from 0.513 to 0.0719 MPa, the flow density varies from 4.64 to 0.66 kg/m 3 , and the flow velocity varies from 0 to 590 m/s. Numerical simulation results have shown that an acoustic field is generated inside the ejector during the mixing of air with water, which accelerates the coagulation of iron particles. The obtained sound power level value of 100 dB shows that the pulsating flow ejector can be used for non-reagent water treatment.

Investigation of Dynamics of Damped Bearing-Rotor System of Centrifugal Milk Separator

“…Numerical simulation was carried out by solving the Navier-Stokes equations that relate momentum, energy conservation and mass laws for fluid flow. Flow Simulation software utilizes Favre-averaged Navier-Stokes equations in which time-averaged effects of the turbulence on the flow parameters are considered, whereas the other, i.e., time-dependent, large-scale phenomena are considered directly [24,25]. During this process, some extra terms known as the Reynolds stresses appear in the equations.…”

“…During this process, some extra terms known as the Reynolds stresses appear in the equations. To close this system of equations, transport equations for the turbulent kinetic energy and its dissipation rate have to be employed (so-called k-ε model [24,25]).…”