A three-dimensional code for rotating blade-row flow analysis has been developed. The space discretization uses a cell-centered scheme with eigenvalue scaling the artificial dissipation. computational efficiency of four-stage Runge–Kutta is enhanced by using variable coefficients, implicit residual smoothing, and full-multigrid method. An application presented NASA rotor 67 transonic fan. Due to blade stagger twist, zonal, nonperiodic H-type grid used minimize mesh skewness. calculation...

Efficient acceleration techniques typical of explicit steady-state solvers are extended to tune-accurate calcu- lations. Stability restrictions greatly reduced by means a fully implicit time discretization. A four-stage Runge-Kutta scheme with local tune stepping, residual smoothing, and multigridding is used instead traditional computationally expensive factorizations. Two applications natural unsteady viscous flows presented check for the capability procedure. ECENT progress in...

A recently developed, time-accurate multigrid viscous solver has been extended to the analysis of unsteady rotor–stator interaction. In proposed method, a fully implicit time discretization is used remove stability limitations. By means dual time-stepping approach, four-stage Runge–Kutta scheme in conjunction with several accelerating techniques typical steady-state solvers, instead traditional time-expensive factorizations. The strategies include local stepping, residual smoothing, and...

The turbomachine industry is increasingly interested in developing automated design procedures that are able to summarize current experience, take into account manufacturing limitations and define new rules for improving machine performance. In this paper, a strategy the parametric analysis optimization of transonic centrifugal impellers was developed, using technique experiments coupled with three dimensional fluid-dynamic solver. geometrical parameterization conducted Bezier curves few...

Efficient acceleration techniques typical of explicit steady-state solvers are extended to time-accurate calculations. Stability restrictions greatly reduced by means a fully implicit time discretization. A four-stage Runge-Kutta scheme with local stepping, residual smoothing, and multigridding is used instead traditional time-expensive factorizations. Some applications natural forced unsteady viscous flows show the capability procedure.

A new kind of C-type grid is proposed, this non-periodic on the wake and allows minimum skewness for cascades with high turning large camber. Reynolds-averaged Navier-Stokes equations are solved type using a finite volume discretization full multigrid method which uses Runge-Kutta stepping as driving scheme. The Baldwin-Lomax eddy-viscosity model used turbulence closure. detailed numerical study proposed highly loaded transonic blade. independence analysis presented in terms pressure...

Parent stocks of meat birds are severely feed restricted to avoid obesity-related health and fertility problems. This restriction often leads chronic hunger, accompanied by stereotypic behavior. Research based in the United Kingdom has shown that using diets containing fiber appetite suppressants may relieve some symptoms hunger. However, few data available regarding North American-sourced ingredients or nondaily feeding regimens. study investigated effects 2 alternative diets, combination...

In low-pressure turbines (LPT) at design point, around 60–70% of losses are generated in the blade boundary layers far from end walls, while remaining 30–40% is controlled by interaction profile with end-wall layer. Increasing attention devoted to these flow regions industrial processes. This paper discusses characteristics T106 parallel walls realistic LPT conditions, as described experimental setup Duden, A., and Fottner, L., 1997, “Influence Taper, Reynolds Number Mach on Secondary Flow...

A quasi-three-dimensional, blade-to-blade, time-accurate, viscous solver was used for a three-stage LP turbine study. Due to the low Reynolds number, transitional computations were performed. Unsteady analyses then carried out by varying circumferential relative position of consecutive vanes and blade rows study effects clocking on turbine’s performance. strategy developed in order limit number configurations be analyzed is discussed. The optimum analytically-determined illustrated two...

A three-dimensional code for viscous cascade flow prediction has been developed. The space discretization uses a cell-centered scheme with eigenvalue scaling to weigh the artificial dissipation terms. Computational efficiency of four-stage Runge-Kutta is enhanced by using variable coefficients, implicit residual smoothing, and full-multigrid method. Baldwin-Lomax eddy-viscosity model used turbulence closure. zonal, nonperiodic grid minimize mesh distortion in downstream throat region....

This paper discusses the application of different transition-sensitive turbulence closures to prediction low-Reynolds-number flows in high-lift cascades operating low-pressure turbine (LPT) conditions. Different formulations well known γ-R˜eθt model are considered and compared a recently developed transition based on laminar kinetic energy (LKE) concept. All those approaches have been coupled Wilcox k-ω model. The performance has assessed by analyzing three cascades, tested experimentally...

This paper presents an efficient ‘Phase-Lagged’ method developed for turbomachinery applications. The is based on the generalized-shape-correction model. Moving average techniques as well double-passage domain formulation were adopted in order to reduce memory requirements and improve model robustness. was used evaluate aerodynamic performance of high-pressure transonic turbine stage CT3, experimentally studied at von Kármán Institute Fluid Dynamics framework EU funded TATEF2 project....

Abstract In low-pressure turbines (LPTs), around 60–70% of losses are generated away from end-walls, while the remaining 30–40% is controlled by interaction blade profile with end-wall boundary layer. Experimental and numerical studies have shown how strength penetration secondary flow depends on characteristics incoming techniques did shed light mechanism that controls growth vortices, scale-resolving computational fluid dynamics (CFD) allowed to dive deep into details vorticity generation....

A computer code for solving the Reynolds-averaged full Navier–Stokes equations has been developed and applied using H- C-type grids. The Baldwin–Lomax eddy-viscosity model is used turbulence closure. integration in time based on an explicit four-stage Runge–Kutta scheme. Local stepping, variable coefficient implicit residual smoothing, a multigrid method have implemented to accelerate steady-state calculations. grid independence analysis presented transonic rotor blade. Comparisons with...

A numerical model was included in a three-dimensional viscous solver to account for real gas effects the compressible Reynolds averaged Navier-Stokes (RANS) equations. The behavior of gases is reproduced by using property tables. method consists local fitting data provide thermodynamic required each solution step. This approach presents several characteristics which make it attractive as design tool industrial applications. First all, implementation simple and straightforward, since does not...

The laminar kinetic energy (LKE) concept has been applied to the prediction of low-Reynolds number flows, characterized by separation-induced transition, in high-lift airfoil cascades for aeronautical low-pressure turbine applications. LKE transport equation coupled with formulation Wilcox's k − ω turbulence model. proposed methodology assessed against two cascade configurations, different loading distributions and suction-side diffusion rates, tested over a wide range Reynolds numbers....

In commercial production, broiler breeders are severely feed restricted to maintain healthy BW. This restriction can induce stereotypic behavior, including feather pecking, which has negative welfare implications for both the victim and performer. It been suggested that problem may be symptomatic of chronic hunger or frustration feeding motivation. this study, we determined whether condition, as an indirect measure could improved via dietary manipulation. Six treatments were tested, each...

Multistage axial compressors have always been a great challenge for designers since the flow within these kind of machines, subjected to severe diffusion, is usually characterized by complex and widely developed 3D structures, especially next endwalls. The development reliable numerical tools capable providing an accurate prediction overall machine performance one main research focus areas in multistage compressor field. This paper intended present strategy used run simulations on achieved...

One and a half stages of low pressure turbine were investigated using three-dimensional time-accurate viscous solver. Unsteady analyses carried out by varying the circumferential relative position consecutive vanes to study effects clocking on performance. Assuming that efficiency improvements are linked wake tangential with respect successive blade, certain shift in this can be observed along blade height due twist nonradial stacking, giving different contributions. In order assess...

A three-dimensional Navier-Stokes solver is used to investigate the flow field of a high-pressure ratio centrifugal compressor for turbocharger applications. Such consists double-splitter impeller followed by vaned diffuser. The inlet open shrouded transonic, thus giving rise interactions between shock waves and boundary layers tip leakage vortices. These generate complex structures which are convected distorted through blades. Detailed laser Doppler velocimetry measurements available at...

A three-dimensional Navier–Stokes solver is used to investigate the flow field of a high pressure ratio centrifugal compressor for turbocharger applications. Such consists double-splitter impeller followed by vaned diffuser. Particular attention focused on analysis diffuser, designed subsonic inlet conditions. The diffuser characterized complex and influenced unsteady interaction with impeller. Detailed particle image velocimetry measurements within are available comparison purposes.

An accurate characterization of rotating stall in terms inception modality, flow structures, and stabilizing force is one the key goals for high-pressure centrifugal compressors. The unbalanced pressure field that generated within diffuser can be fact connected to a non-negligible aerodynamic then onset detrimental subsynchronous vibrations, which prevent machine from operating beyond this limit. inner comprehension on how induced pattern these conditions affects performance impeller its...

The design of radial-inflow turbines usually relies on one-dimensional or mean-line methods. While these approaches have so far proven to be quite effective, they can not assist the designer in coping with some important issues, such as mechanical integrity and complex flow features. Turbo-expanders are general characterized by fully three-dimensional fields, strongly influenced viscous effects passage curvature. In particular, for high pressure ratio applications, organic Rankine cycles,...

Within the European research project RECORD (Research on Core Noise Reduction) tone noise emissions of a high-pressure turbine stage have been numerically evaluated by six different academic and industrial partners. The geometry operating conditions match an HPT test rig located at Politecnico di Milano (Italy). Since constant demand for quieter greener propulsion systems has led to development several numerical aeroacoustic codes, this common benchmark represents important chance compare...