The simulation of the three-dimensional turbulent flow in turbomachines is currently based on the solution of the Reynolds Averaged Navier Stokes equations. A considerable computational effort usually goes to the mesh generation process due to the complexity of the impeller geometry. The use of Cartesian grids combined with a numerical technique for solving partially blocked cells is presented ...

the aim of this study is designing the impeller of a centrifugal compressor in order to supply pressure ratio for a 65 kw micro gas turbine. first, the primary thermodynamic analysis has been conducted for the considered cycle using a home made code. herein, the compressor pressure ratio was considered to be 4. the obtained thermal efficiency was 25.64%. then, the design of micro compressor in ...

During the startup process of a centrifugal pump, vibration and noise problems caused by unsteady flow are focus attention, pressure pulsation is one main reasons for this problem. In current research, special impeller with blade side trimming was proposed to reduce strong phenomenon during pumps. This article uses numerical simulation methods simulate three typical trailing edges: original edg...

In this paper the numerical simulation of flow field in the new design dynamic cyclone separator is investigated. The effects of different geometrical parameters such as impeller diameter, number of vanes, length and the location of impeller is investigated. The Reynolds averaged Navier–Stokes equations with Reynolds stress turbulence model (RSM) were solved. The Eulerian-Lagrangian computation...

Problem Statement: Mixing filamentous fungi entails delicate balance between promoting high volumetric oxygen transfer coefficient (kLa) while keeping low hydrodynamic stresses in the microenvironment of cultures. This study examined the oxygen transfer capability of a prototype low shear helical impeller as a potential replacement for the standard Rushton turbine. Approach: The dependence of k...

Traditional commercial centrifugal pump designs have specific speeds (Ns) greater than 500 because low values of Ns are usually associated with low efficiency, pulsation, and a drooping head characteristic. In this instance, acceptable hydraulic performance is achieved with a unique impeller design coupled with direct current (DC) motor characteristics. When the specific speed of a centrifugal ...

The turbulence dissipation rate and turbulence shear stress are estimated inside a cylindrical, stirred flow mixer by carrying out Stereo PIV measurements in twelve vertical and three horizontal planes. The flow domain is vertically oriented, filled with the water. A commercially-available, three-blade impeller, HR-100, is used as the agitator. The impeller is mounted near the tip of a thin, ri...

A narrative integrative review on the evidence for hoof trimming found 16 articles on efficacy, frequency, and associations with behavior and physiologic parameters. Review of these studies revealed (1) hoof trimming is associated with behavior and physiologic changes; (2) increasing the frequency of hoof trimming seems to decrease the incidence of hoof lesions; (3) there is limited research to...

OBJECTIVE In a univentricular Fontan circulation, modest augmentation of existing cavopulmonary pressure head (2-5 mm Hg) would reduce systemic venous pressure, increase ventricular filling, and thus substantially improve circulatory status. An ideal means of providing mechanical cavopulmonary support does not exist. We hypothesized that a viscous impeller pump, based on the von Kármán viscous ...

The transformation frequency of Escherichia coli C-600, continuously cultivated in a chemostat operated at constant dilution rate, increased with increase in agitation rate (impeller speed). Cell counts at each impeller speed remained approximately constant. The phenomenon correlated with changes in mean cell volume associated with the changes in agitation rate.