Swirling Flow Research Papers - Academia.edu (original) (raw)

The United Nations estimates that 1 billion people worldwide access to electricity, has a poor power quality. China has an installed capacity of hydroelectric power plants ranked first in the world. The United Nations estimates that 1... more

The United Nations estimates that 1 billion people worldwide access to electricity, has a poor power quality. China has an installed capacity of hydroelectric power plants ranked first in the world. The United Nations estimates that 1 billion people poor quality of electricity. . From the above five countries are aggressively developing micro hydro as in the graph below show, from five countries such as Russia, USA, Canada, Brazil, China had an installed capacity of hydroelectric power plants ranked first in the world. In 2011, the national electrification ratio only amounted to 72.95% . A total of 27.05% in Indonesian territory has not reached by electricity with diverse obstacles, either because the remote location so that access is difficult. One attempt to do to resolve the electricity problem is to exploit the potential of existing energy sources around the residence society. One of the potential that may be used is the energy source of water. From a survey conducted in rural . showed that much of the energy sources of water around settlements with head and low discharge. Utilization of water sources with discharge as described above, ideally performed by using a system that uses a generator turbine type propeller. The turbine in addition to expensive and difficult to make than in the other turbines that can be used for low head like a cross flow. The difficulty of making a turbine propeller especially at home and turbine blade manufacture. In this research in the search effort for simplification of the turbine casing and turbine blades so easily made. Simplification of the turbine casing is done by making the turbine casing of iron pipes and simplification of turbine blades is done by making a turbine blade by removing an aerodynamic cross-section of the blade, so the blade can be made of steel plate without casting as treated on an aerodynamic cross-section. Keywords : low head, blade, simplification,aerodinamic, non aerodinamic,

Axisymmetric solution of radial, axial and tangential components of velocity of flow through a cylindrical chamber with an inflow containing swirl and outflow is investigated numerically using Finite Volume Method. An in-house developed... more

Axisymmetric solution of radial, axial and tangential components of velocity of flow through a cylindrical chamber with an inflow containing swirl and outflow is investigated numerically using Finite Volume Method. An in-house developed computer code for solving the three components of velocity and pressure is developed and validated using experimental data available from literature on the problem of axial vortex breakdown of confined flow in a cylinder due to rotation of one of the end walls. The code uses a staggered approach and fractional step projection method for decoupling the velocity and pressure. The convection and diffusion terms are approximated using a second-order accurate central difference scheme. This paper discusses the characteristics features of flow such as mixing streams, streams of fluid flowing close to the solid walls(cooling streams), swirl motion and development of flow structures.

Abstract Fluid flow phenomena in a cylindrical bath stirred by a top submerged lance (TSL) gas injection was investigated by using the computational fluid dynamic (CFD) modeling technique for an isothermal air–water system. The multiphase... more

Abstract Fluid flow phenomena in a cylindrical bath stirred by a top submerged lance (TSL) gas injection was investigated by using the computational fluid dynamic (CFD) modeling technique for an isothermal air–water system. The multiphase flow simulation, based on ...

The paper presents a numerical investigation of the 3D inviscid and incompressible swirling flow in a pipe with constant diameter. In order to evaluate the influence of different parameters (numerical schemes, grid refinement,... more

The paper presents a numerical investigation of the 3D inviscid and incompressible swirling flow in a pipe with constant diameter. In order to evaluate the influence of different parameters (numerical schemes, grid refinement, velocity-pressure coupling methods, outlet boundary conditions) the 3D Euler computations were performed. The 3D computational domain corre- sponds to a pipe with constant diameter. The objective of

Impinging jets are widely used for their effective heat and mass transfer for several decades. Arrays of jet impingement have also been studied before due to its practical relevance to electronics cooling. A number of jet variations and... more

Impinging jets are widely used for their effective heat and mass transfer for several decades. Arrays of jet impingement have also been studied before due to its practical relevance to electronics cooling. A number of jet variations and jet-to-jet orientations have previously been studied, mainly to further improve the magnitude and uniformity of heat transfer. In recent years, swirling jets has also gained interest in heat transfer application due to their inherent mixing and spreading characteristics, which is believed to be an improvement on overall heat and mass transfer. As such, this paper numerically investigates an array of circular jets with and without swirl that impinges vertically onto a flat surface located at a fixed vertical distance H = 2D and at Reynolds number equals to 11,600, where D is the nozzle diameter. As the entire was symmetric, only quarter of the model was constructed for numerical analysis to save computational cost. In this case, numerical calculations were done via commercial software package ANSYS Fluent using SST k-ω turbulence model. Inlet conditions were taken from experimental data. The jet flows were in downward direction and gravity was not considered. This paper also compares numerical predictions with previously published literature for non-swirling and swirling jets.

This work studied how in-cylinder flow structure is affected in a light-duty, swirl-supported diesel engine, when equipped with three different piston geometries: the first two featuring a conventional re-entrant bowl, either with or... more

This work studied how in-cylinder flow structure is affected in a light-duty, swirl-supported diesel engine, when equipped with three different piston geometries: the first two featuring a conventional re-entrant bowl, either with or without valve cutouts on the piston surface, and the third featuring a stepped-lip bowl. Particle Image Velocimetry (PIV) experiments were conducted inside an optical engine to measure swirl vortex intensity and structure during the intake and compression strokes. A full computational model of the optical diesel engine was built using the FRESCO code, a recently developed object-oriented parallel CFD platform for engine simulations. The model was first validated against the measured swirl-plane velocity fields, and the simulation convergence for multiple cycles was assessed. Flow topology was studied by addressing bulk flow and turbulence quantities, including swirl structure, squish flux, plus geometric and operating parameters, such as the presence of valve cutouts on the piston surface, compression ratio and engine speed. The results demonstrated that conventional re-entrant bowls have stronger flow separation at intake, hampering bowl swirl, but higher global swirl than for stepped-lip bowls thanks to a stronger and more axisymmetric squish mechanism, and less tilted swirl. Stepped-lip bowls have larger in-homogeneities (tilt, axisymmetry) and higher turbulence levels, but also faster turbulence dissipation towards top dead center. They have weaker squish flux but larger squish inversion momentum as a result of the smaller inertia.

This paper presents the effect of inserting swirler outlet orifice plate of different sizes at the exit plane of the flat blade radial air swirler in liquid fuel burner system. Tests were carried out with three different orifice plates... more

This paper presents the effect of inserting swirler outlet orifice plate of different sizes at the exit plane of the flat blade radial air swirler in liquid fuel burner system. Tests were carried out with three different orifice plates with area ratios (orifice area to swirler exit area ratio) between 1.0 to 0.7 using 280 mm inside diameter combustor of

We report a novel and spectacular instability of a fluid surface in a rotating system. In a flow driven by rotating the bottom plate of a partially filled, stationary cylindrical container, the shape of the free surface can spontaneously... more

We report a novel and spectacular instability of a fluid surface in a rotating system. In a flow driven by rotating the bottom plate of a partially filled, stationary cylindrical container, the shape of the free surface can spontaneously break the axial symmetry and assume the form of a polygon rotating rigidly with a speed different from that of the

In this study, an exact Eulerian solution is derived for the bidirectional vortex in a conical chamber. Our model is applicable to idealized representations of cyclone separators and liquid rocket engines with slowly expanding chamber... more

In this study, an exact Eulerian solution is derived for the bidirectional vortex in a conical chamber. Our model is applicable to idealized representations of cyclone separators and liquid rocket engines with slowly expanding chamber cross-sections. The bulk fluid motion is assumed to be nonreactive, steady, rotational, inviscid, and incompressible. Our approach is founded on the Bragg-Hawthorne equation and seeks to overcome some of the deficiencies encountered by Bloor and Ingham (Bloor, M. I. G., and Ingham, D. B., “The Flow in Industrial Cyclones,” Journal of Fluid Mechanics, Vol. 178, 1987, pp. 507-519). Despite inevitable similarities with Bloor and Ingham’s model, ours is constructed using a judicious framework that connects the solution to the swirl number and the cone divergence angle. In consequence, a self-similar formulation is produced that is independent of the cone’s finite body length. closed-form representations for the principal variables This enables us able to c...

In this paper the laminar axisymmetric swirling flow of an incompressible viscous fluid from the entry to the fully developed downstream region in a straight circular pipe of uniform cross-section has been studied. The swirl has been... more

In this paper the laminar axisymmetric swirling flow of an incompressible viscous fluid from the entry to the fully developed downstream region in a straight circular pipe of uniform cross-section has been studied. The swirl has been prescribed at the entry, along with the longitudinal flow. The development of the flow has been divided into three regions and the analysis is based on the method of matched asymptotic expansions.In dieser Arbeit wird die laminare achsensymmetrische Wirbelströmung einer inkompressiblen viskosen Flüssigkeit in einem geraden kreisförmigen Rohr mit gleichbleibendem Querschnitt vom Eintritt bis zum voll entwickelten Fallstrombereich untersucht. Der Wirbel wird beim Eintritt zusammen mit der Längsströmung vorgegeben. Die Entwicklung der Strömung wird in drei Bereiche eingeteilt, wobei die Analyse mittels angepaßter asymptotischer Reihen durchgeführt wird.

Our recent results on stability and multiplicity of flow states for confined flows of an incompressible Newtonian fluid are surveyed. The considered laminar flows are caused by either thermal, mechanical, or electromagnetic effects and... more

Our recent results on stability and multiplicity of flow states for confined flows of an incompressible Newtonian fluid are surveyed. The considered laminar flows are caused by either thermal, mechanical, or electromagnetic effects and beyond the stability limit exhibit multiplicity of stable, steady or oscillatory, asymptotic states. Stability diagrams as well as examples of multiple flow states are given. It

Despite the recent upsurge of theoretical reduced models for vesicle shape dynamics, comparisons with experiments have not been accomplished. We review the implications of some of the recently proposed models for vesicle dynamics,... more

Despite the recent upsurge of theoretical reduced models for vesicle shape dynamics, comparisons with experiments have not been accomplished. We review the implications of some of the recently proposed models for vesicle dynamics, especially the Tumbling-Trembling domain regions of the phase plane and show that they all fail to capture the essential behavior of real vesicles for excess areas, \Delta, greater than 0.4. We emphasize new observations of shape harmonics and the role of thermal fluctuations.

Direct numerical simulation data from the self similar region of a planar mixing layer is filtered at four different length scales, from the Taylor microscale to the dissipative scales, and is used to examine the scale dependence of the... more

Direct numerical simulation data from the self similar region of a planar mixing layer is filtered at four different length scales, from the Taylor microscale to the dissipative scales, and is used to examine the scale dependence of the strain-rotation interaction in shear flow turbulence. The interaction is examined by exploring the alignment between the extensive strain-rate eigenvector and the vorticity vector. Results show that the mechanism for enstrophy amplification (propensity of which increases when the two vectors are parallel) is scale dependent with the probability of the two vectors being parallel higher for larger length scales. However, the mechanism for enstrophy attenuation, i.e., the probability of the two vectors being perpendicular to each other, appears to be scale independent.