A hybrid method for the simulation of Reynolds-averaged turbulent ̄ows in axial ̄ow impeller driven mixing vessels is described. The time-mean ̄ow in the impeller region is modelled using blade element theory, while the ̄ow in the remainder of the vessel is simulated using a second-order ®nite-volume Reynolds-averaged numerical scheme. The two models are iteratively coupled through boundary con...

The VentrAssist implantable rotary blood pump (IRBP) is a centrifugal pump that uses a hydrodynamic bearing to support its impeller. The pump is to be used as a left ventricular assist device (LVAD). Varying pump speed can control the degree of left ventricular assistance. By increasing impeller speed, it is possible to transition from the normal physiological state of ventricular ejection (VE)...

According to tradition, permanent maglev cannot achieve stable equilibrium. The authors have developed, to the contrary, two stable permanent maglev impeller blood pumps. The first pump is an axially driven uni-ventricular assist pump, in which the rotor with impeller is radially supported by two passive magnetic bearings, but has one point contact with the stator axially at standstill. As the ...

To finalize the design of the next generation of the HeartQuest left ventricular assist device, a suitable impeller had to be designed and tested. The new prototype was based on calculations and test results of previous designs, but required several changes to decrease the size. For most pump designs, this is a simple matter of altering impeller geometry and rotational speed to achieve the desi...

The flow hydrodynamics in a low specific speed radial pump-turbine reduced scale model is experimentally investigated under off-design operating conditions in generating mode. Wall pressure measurements, in the stator, synchronized with high-speed flow visualizations in the vaneless space between the impeller and the guide vanes using air bubbles injection are performed. When starting from the ...

the non-uniformity factor is used for correction of the formulas obtained from the one-dimentional fluid flow method in a centrifugal impeller pump. the variations of radial velocity at the outlet of five centrifugal impellers with the specific speed of about ns =50 are calculated at design point by using two-dimentional potentional flow method for an invisid fluid. on the other hand~ the varia...

An experiment in forced vibration was conducted to study the fluidinduced rotordynamic force on an impeller whirling along a trajectory eccentric to its undeflected position. The prescribed whi l trajectory of the rotor is a circular orbit of a b e d radius. The force measured is a combination of a steady radial force due to volute asymmetries and an unsteady force due to the eccentric motion o...

Centrifugal compressors are most widely used in large capacity refrigeration and air conditioning plants. Its other applications include in gas turbines for air craft applications, diesel engine turbochargers, chemical and process industries, factory workshop air supplies etc. In refrigeration field these are suitable for high specific volume refrigerants or low pressure stages. They have been ...

in this research, the effect of micro turbulence on the flotation rate of quartz particles was investigated. the maximum particle reynolds number (rep) was obtained at 60.25 with a particle size of -500+420 µm, impeller speed of 900 rpm, bubble surface area flux of 10.21 1/s and micro scale turbulence size of 162 µm. when the micro turbulence size was equal to the particle size, the maximum flo...

Stirred tank reactors are one of the most commonly used equipments in industry for achieving mixing and reaction. Flow fields in a stirred reactor are obtained via computational fluid dynamics. In this work CFD is used for the simulation of a reactive flow process consisting of a second order reaction. The extent of reaction is found to depend on impeller speed and its position from the bottom ...