Axisymmetric plastic expansion of a cylindrical hole in isotropic metallic foam

2012 ◽  
Vol 64 (1) ◽  
pp. 165-173 ◽  
Author(s):  
Z. Fan ◽  
T.X. Yu ◽  
G. Lu
Keyword(s):  
Cylindrical Hole ◽  
Metallic Foam ◽  
Axisymmetric Plastic

Finite element simulation of mechanical behaviour of nickel-based metallic foam structures

2009 ◽  
Vol 471 (1-2) ◽  
pp. 147-152 ◽  
Author(s):  
Sid-Ali Kaoua ◽  
Djaffar Dahmoun ◽  
Abd-Elmouneim Belhadj ◽  
Mohammed Azzaz
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
Mechanical Behaviour ◽  
Metallic Foam ◽  
Element Simulation

Assessment of a Double Hole Film Cooling Geometry Using S-PIV and PSP

2013 ◽  
Author(s):  
Lesley M. Wright ◽  
Stephen T. McClain ◽  
Charles P. Brown ◽  
Weston V. Harmon
Keyword(s):  
Film Cooling ◽  
Density Ratio ◽  
Three Dimensional ◽  
Field Measurements ◽  
Secondary Flows ◽  
Cylindrical Hole ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Hole Geometry ◽  
Compound Angle

A novel, double hole film cooling configuration is investigated as an alternative to traditional cylindrical and fanshaped, laidback holes. This experimental investigation utilizes a Stereo-Particle Image Velocimetry (S-PIV) to quantitatively assess the ability of the proposed, double hole geometry to weaken or mitigate the counter-rotating vortices formed within the jet structure. The three-dimensional flow field measurements are combined with surface film cooling effectiveness measurements obtained using Pressure Sensitive Paint (PSP). The double hole geometry consists of two compound angle holes. The inclination of each hole is θ = 35°, and the compound angle of the holes is β = ± 45° (with the holes angled toward one another). The simple angle cylindrical and shaped holes both have an inclination angle of θ = 35°. The blowing ratio is varied from M = 0.5 to 1.5 for all three film cooling geometries while the density ratio is maintained at DR = 1.0. Time averaged velocity distributions are obtained for both the mainstream and coolant flows at five streamwise planes across the fluid domain (x/d = −4, 0, 1, 5, and 10). These transverse velocity distributions are combined with the detailed film cooling effectiveness distributions on the surface to evaluate the proposed double hole configuration (compared to the traditional hole designs). The fanshaped, laidback geometry effectively reduces the strength of the kidney-shaped vortices within the structure of the jet (over the entire range of blowing ratios considered). The three-dimensional velocity field measurements indicate the secondary flows formed from the double hole geometry strengthen in the plane perpendicular to the mainstream flow. At the exit of the double hole geometry, the streamwise momentum of the jets is reduced (compared to the single, cylindrical hole), and the geometry offers improved film cooling coverage. However, moving downstream in the steamwise direction, the two jets form a single jet, and the counter-rotating vortices are comparable to those formed within the jet from a single, cylindrical hole. These strong secondary flows lift the coolant off the surface, and the film cooling coverage offered by the double hole geometry is reduced.

General Features of Plastic-Elastic Problems as Exemplified by Some Particular Solutions

1949 ◽  
Vol 16 (3) ◽  
pp. 295-300
Author(s):  
Rodney Hill
Keyword(s):  
Spherical Shell ◽  
Infinite Medium ◽  
Cylindrical Hole ◽  
Particular Solutions ◽  
Complete Solutions ◽  
Complex Cases

Abstract New complete solutions based upon the Reuss equations are obtained for various plastic-elastic problems. These include the expansion of a spherical shell and of a cylindrical hole in an infinite medium. The solutions are used to exemplify certain features common to all plastic-elastic problems, with a view to introducing valid approximations in more complex cases.

Effects of Film Hole Shape and Turbulence Intensity on the Thermal Field Downstream of Single Row Film Holes

2020 ◽  
Author(s):  
Zheng Zhang ◽  
Hui-ren Zhu ◽  
Wei-jiang Xu ◽  
Cun-liang Liu ◽  
Zhuang Wu
Keyword(s):  
Secondary Flow ◽  
Inclination Angle ◽  
Water Drop ◽  
Lateral Diffusion ◽  
Cylindrical Hole ◽  
Normal Velocity ◽  
Hole Shape ◽  
Blowing Ratio ◽  
Nylon Mesh ◽  
Shaped Hole

Abstract A nylon mesh coated with broadband thermochromic liquid crystal was set in different planes perpendicular to the mainstream direction at various locations downstream of the film hole. By the temperature visualization technique, the colorful non-dimensional temperature images on the nylon mesh of cylindrical hole, water-drop hole and dustpan shaped hole at different blowing ratios and turbulence at angle of 30° and 60° were visualized. The visualization experiment visually studied the effects of hole shape, hole inclination angle, blowing ratio and mainstream turbulence on the distribution of the film. The results show that stream-wise diffusion of water-drop hole reduces kidney vortex intensity, making higher attachment of the film of water-drop than that of cylindrical hole, consequently the lateral coverage range of water-drop hole film is wider than that of cylindrical hole film. The lateral diffusion of dustpan shaped hole further reduces the kidney vortex intensity. This obviously increases the film coverage and strengthens the adhesion of film of dustpan shaped hole. Increasing the inclination angle of the hole and the blowing ratio will increase the normal velocity of the jet and increase the thickness of the film. however, increasing inclination angle and blowing ratio will enhance kidney vortex intensity and decrease the film cooling effectiveness. The high turbulent intensity of mainstream will enhance the lateral diffusion of the film and enhance the mixing of the secondary flow and mainstream, so the continuity and uniformity of film are better. However, the intense mix of secondary flow and mainstream results in the non-dimensional temperature of the film drops sharply and the film coverage reduced accordingly.

Periodic Forced Convection in a Darcy Metallic Foam: The LTNE Model

2012 ◽  
Author(s):  
Eugenia Rossi di Schio ◽  
Antonio Barletta
Keyword(s):  
Forced Convection ◽  
Outer Boundary ◽  
Method Of Lines ◽  
Mean Value ◽  
Entrance Region ◽  
Solid Matrix ◽  
Metallic Foam ◽  
The Method Of Lines ◽  
Thermal Entrance Region ◽  
Thermal Entrance

The present paper studies the thermal entrance region in a concentric annular duct filled by a fluid saturated porous metallic foam, with reference to steady forced convection and to a thermal boundary condition given by a wall temperature longitudinally varying with a sinusoidal law. The effect of viscous dissipation in the fluid is taken into account, and a two-temperature model is employed in order to evaluate separately the local fluid and solid matrix temperatures. The governing equations in the thermal entrance region are solved numerically by the method of lines. The Nusselt numer and its mean value in an axial period is evaluated, with reference both to the inner and the outer boundary.

Laser Beam Welding of Open-Porous Metallic Foams for Application in Cooling Structures of Combined Cycle Power Plants

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
Uwe Reisgen ◽  
Simon Olschok ◽  
Stefan Longerich
Keyword(s):  
Laser Beam ◽  
Power Plants ◽  
Laser Beam Welding ◽  
Combined Cycle ◽  
Metallic Foam ◽  
Research Centre ◽  
Combustion Chambers ◽  
Multilayer Systems ◽  
Wall Area ◽  
Graded Structures

Within the Collaborative Research Centre 561, “Thermally highly loaded, porous and cooled multilayer systems for combined cycle power plants,” open-porous and high-temperature stable Ni-based structures are being developed for the requirements of effusion cooling. A two-dimensional cooling strategy for the walls of combustion chambers, which allows the outflow of the cooling medium over the complete wall area of the combustion chamber, could be realized by an open-porous metallic foam structure. The open-porous metallic foam is produced by the “slip reaction foam sintering” process, a powder metallurgical process. To join several foams to assemble structural elements, laser beam welding has been used. Different joining strategies have been examined to find out the most suitable method to join these foams. In this paper, the process setups, settings of the different strategies, and results of trials (seam geometry and strength tests) are discussed. The need for graded structures to combine the essential permeability and adequate weldability is also shown.

Sign in / Sign up

Export Citation Format

Share Document