This study explores the characteristics of twin-screw pumps when operated in turbine, i.e., reverse mode as an alternative to traditional control valves piping systems for recovering energy. Experimental and flow simulation methods are employed. By overset grid technique, unsteady three-dimensional (3D) simulations conducted, ensuring high cell quality spatial resolution, particularly wall proximity within gaps. To assess viscosity effects, pump turbine analyzed water oil. Compared water, a...

As a contribution to better understanding of cavitation erosion mechanisms, compressible inviscid finite volume flow solver with barotropic homogeneous liquid-vapor mixture model is applied ultrasonic horn set-ups and without stationary specimen, that exhibit attached at the tip. Void collapses shock waves, which are closely related erosion, resolved. The computational results compared hydrophone, shadowgraphy test data. At tip, vapor topology, subharmonic oscillation frequency as well...

Three-dimensional (3D) simulations with ansys cfx 16.1 as well measurements of the cavitating flow in a low specific speed centrifugal pump (nq = 12 min−1) are performed for different operation conditions and varying surface roughness. Surface roughness is considered by wall functions simulations. Good agreement between measured calculated head achieved noncavitating flow. Net positive suction (NPSH3%) rises toward overload due to incidence, separation, vapor zones at volute tongue. The...

Abstract Three-dimensional (3D) unsteady Reynolds-averaged Navier–Stokes (URANS) flow simulations are conducted to investigate the highly field at part load operation of a centrifugal pump. By availability measurement data in impeller wake region, thorough validation simulation method is performed. Grid independence results ensured. Unsteady characteristics terms head and shaft power as well transient blade loads evaluated assess pump performance. Significant mis-loading blading revealed...

A novel three-dimensional/one-dimensional (3D/1D) coupled simulation method is applied to study cavitation dynamics in a simplex plunger positive displacement pump. The compressible 3D unsteady Reynolds-averaged Navier–Stokes equations are solved by finite volume method, using deforming meshes and two-way fluid–structure interaction approach for modeling fluid-actuated valve dynamics. incorporates mass transfer model accounts non-dissolved air. Structural compliance approximated an enhanced...

Abstract An assessment of a two-fluid model assuming continuous liquid and dispersed gas phase for 3D computational fluid dynamics (CFD) simulations gas/liquid flow in centrifugal research pump is performed. A monodisperse model, conjunction with statistical eddy-viscosity turbulence utilized. By comprehensive measurement database, thorough inaccuracies enabled. The results on horizontal diffuser reveal that the one main limitation simulation accuracy flows. Regarding flows, distinctions...

Abstract A local loss analysis (LLA) based on entropy production is presented for the numerical three-dimensional (3D) simulation of isothermal centrifugal pump flow. finite volume method and a statistical turbulence model are employed. Wall functions direct turbulent in flow derived, implemented node-centered scheme as postprocessing procedure, validated an attached channel well separated asymmetric diffuser. The integrity wall function demonstrated by balance wide range boundary layer...

Cavitation induced wall loads at an ultrasonic horn facility are analyzed by 3D flow simulations and temporally high-resolved pressure measurements for varying gap widths between stationary erosion specimen. Piezoelectric polyvinylidene fluoride (PVDF) probes placed different radial positions the specimen opposite of oscillation yield a declining aggressiveness with increasing position width. The measurement results reproduced virtual in CFD simulations. Pressure measure terms load...

The acoustic properties of a single-stage centrifugal pump with low specific speed are investigated by means compressible 3D CFD simulations (URANS) and experiments. In order to determine the pump’s transmission excitation characteristics, four-pole approach in frequency domain is used. parameters determined simulation compared experiments water air as functions Helmholtz number. results indicate that characteristics within significantly influenced structural compliance volute casing terms...

Predicting pump performance and ensuring operational reliability under two-phase conditions is a major goal of three-dimensional (3D) computational fluid dynamics (CFD) analysis liquid/gas radial centrifugal flows. Hence, 3D CFD methods are increasingly applied to such flows in academia industry. The demands careful selection sub-models from several fields CFD, as turbulence modeling, well high-quality meshing complex geometries. This paper presents an overview current simulation strategies,...

Abstract This study investigates the flow field induced by a surface dielectric barrier discharge (SDBD) system, known for its efficient pollution remediation of volatile organic compounds (VOCs). We aim to understand dynamics that contribute high conversion observed in similar systems using this specific SDBD design. Examining how affects gas mixing chemical processes is important both understanding fundamentals and potential industrial applications. Experimental techniques, including...

Abstract A compressible finite volume Navier–Stokes flow solver is coupled to a method of characteristics for the seamless turbulent simulation entire pump systems. For pump, three-dimensional (3D) simulations including cavitating conditions are performed, and piping treated one-dimensional (1D) by characteristics. Thus, classical boundary at suction pressure pipe 3D computational domain substituted two-way 1D method. Particular emphasis has been placed on non-reflecting properties 3D–1D...

Cavitation leads to rapid degassing of fluids. Up date, there is a lack model approaches cavitation-induced degassing. The aim the present study gain more thorough knowledge process. Therefore, relation between cavitation intensity and air release investigated experimentally for an orifice flow as function number. For this, shadowgraphy imaging used visualize regions steam volume downstream orifice. Analysis images shows strongly nonlinear scaling behavior both Three distinct regimes could...