Pressure Increase in Elliptical Impact EHL Contacts With Surface Asperities

2012 ◽  
Author(s):  
M. Kaneta ◽  
F. Guo ◽  
J. Wang ◽  
I. Krupka ◽  
M. Hartl
Keyword(s):  
High Pressure ◽  
Numerical Analysis ◽  
Steel Plate ◽  
Pressure Level ◽  
Pressure Increase ◽  
Local Pressures ◽  
Steel Body

The phenomena which occur when a spherical steel body impacts a stationary steel plate with surface asperities are discussed through isothermal Newtonian numerical analysis using sinusoidal roughness. The ridges of the sinusoidal roughness produce large local pressures, particularly in elliptical contacts, when constant loads are imposed on the contact by impact. The pressure level is usually larger when the ridges are located along the major contact direction than along the minor contact direction, and increases as the loading speed increases. The high pressure induces a micro-groove in the ridge and the horse-shoe shaped constriction is formed at the ridges locating around the contact edge.

Pressure Increase in Elliptical Impact Elastohydrodynamic Lubrication Contacts With Longitudinal Asperities

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
M. Kaneta ◽  
F. Guo ◽  
J. Wang ◽  
I. Krupka ◽  
M. Hartl
Keyword(s):  
Numerical Analysis ◽  
Applied Load ◽  
Steel Plate ◽  
Elastohydrodynamic Lubrication ◽  
Major Axis ◽  
Minor Axis ◽  
Pressure Increase ◽  
Local Pressures ◽  
Ellipticity Ratio ◽  
Steel Body

The phenomena that occur when an elliptical steel body impacts a stationary steel plate with surface asperities are discussed through isothermal Newtonian numerical analysis using sinusoidal roughness. The ridges of the surface asperities produce large local pressures, especially at a large ellipticity ratio, when the surfaces are approaching each other under the applied load. The values of the local pressures are larger when the ridges are along the major axis than when the ridges are along the minor axis. Furthermore, as the loading speed increases, the pressure increases. As a result, the microgrooves are produced in the ridges and the horseshoe-shaped constrictions are formed at the ridges located around the contact edge.

Auto-Ignition and Numerical Analysis on High-Pressure Combustion of Premixed Methane-Air mixtures in Highly Preheated and Diluted Environment

2021 ◽  
pp. 1-23
Author(s):  
Subrat Garnayak ◽  
Ayman M Elbaz ◽  
Olawole Kuti ◽  
Sukanta Kumar Dash ◽  
William L Roberts ◽  
...  
Keyword(s):  
High Pressure ◽  
Numerical Analysis ◽  
Auto Ignition

scholarly journals Role of temperature in the numerical analysis of CaO under high pressure

2010 ◽  
Vol 8 (1) ◽  
pp. 126-133 ◽  
Author(s):  
Purvee Bhardwaj ◽  
Sadhna Singh
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Numerical Analysis ◽  
Thermodynamic Properties ◽  
Elastic Constants ◽  
Volume Change ◽  
Thermodynamical Properties ◽  
Phase Transition Pressure ◽  
Different Temperatures

AbstractIn this paper we focus on the elastic and thermodynamic properties of the B1 phase of CaO by using the modified TBP model, including the role of temperature. We have successfully obtained the phase transition pressure and volume change at different temperatures. In addition elastic constants and bulk modulus of B1 phase of CaO at different temperatures are discussed. Our results are comparable with the previous ones at high temperatures and pressures. The thermodynamical properties of the B1 phase of CaO are also predicted.

scholarly journals NUMERICAL ANALYSIS OF CORRUGATED STEEL PLATE BRIDGE WITH REINFORCED CONCRETE RELIEVING SLAB

2015 ◽  
Vol 22 (5) ◽  
pp. 585-596 ◽  
Author(s):  
Damian BEBEN ◽  
Adam STRYCZEK
Keyword(s):  
Reinforced Concrete ◽  
Numerical Analysis ◽  
Steel Plate ◽  
Numerical Models ◽  
Experimental Tests ◽  
Bridge Engineering ◽  
Steel Plates ◽  
The Finite Element Method ◽  
Calculation Results ◽  
Rc Slab

The paper presents a numerical analysis of corrugated steel plate (CSP) bridge with reinforced concrete (RC) relieving slab under static loads. Calculations were made based on the finite element method using Abaqus software. Two computation models were used; in the first one, RC slab was used, and the other was without it. The effect of RC slab to deformations of CSP shell was determined. Comparing the computational results from two numerical models, it can be concluded that when the relieving slab is applied, substantial reductions in displacements, stresses, bending mo­ments and axial thrusts are achieved. Relative reductions of displacements were in the range of 53–66%, and stresses of 73–82%. Maximum displacements and bending moments were obtained at the shell crown, and maximum stresses and axial thrusts at the quarter points. The calculation results were also compared to the values from experimental tests. The course of computed displacements and stresses is similar to those obtained from experimental tests, although the absolute values were generally higher than the measured ones. Results of numerical analyses can be useful for bridge engineering, with particular regard to bridges and culverts made from corrugated steel plates for the range of necessity of using additional relieving elements.

Estimation of Frictional Coefficient between Punch and Billet at Back-Stroke in Backward Can Extrusion Test of Steel

2018 ◽  
Vol 767 ◽  
pp. 248-255
Author(s):  
Kazuhito Asai ◽  
Kazuhiko Kitamura ◽  
Keisuke Goto ◽  
Nobukazu Hayashi
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Numerical Analysis ◽  
Frictional Coefficient ◽  
Expansion Ratio ◽  
Coated Steel ◽  
Forward Stroke ◽  
High Pressure High Temperature ◽  
The Coefficient Of Friction ◽  
Surface Expansion

A backward can extrusion test provides severe tribological conditions because high pressure, high temperature, and large surface expansion ratio affect the lubricant. During the forward stroke these conditions intensify with increasing cup depth of the extruded workpiece; additionally, the back-stroke force during retraction of the punch rises to a significant level under a poor-lubricated condition. This study estimates the coefficient of friction μp between punch and workpiece during the back-stroke by combining experiments using conventional soap-phosphate coated steel and numerical analysis by FEM. The values of μp were estimated to be 0.09 and 0.03 in case of small and large workpiece depth, respectively. Friction decreased with elevating temperature.

Microbiological Changes in Pressurized, Prepackaged Sliced Cooked Ham

1999 ◽  
Vol 62 (12) ◽  
pp. 1411-1415 ◽  
Author(s):  
M. E. LÓPEZ-CABALLERO ◽  
J. CARBALLO ◽  
F. JIMÉNEZ-COLMENERO
Keyword(s):  
High Pressure ◽  
Processing Time ◽  
Microbiological Quality ◽  
Viable Count ◽  
Pressure Level ◽  
Binding Properties ◽  
Water Binding ◽  
Chilled Storage ◽  
Cooked Ham ◽  
Brochothrix Thermosphacta

This was a study of the influence of high-pressure conditions (200 and 400 MPa, 5 and 20 min, 7°C) on microbiological quality and water-binding properties of vacuum-prepackaged sliced cooked ham and how this affects microbiological changes during chilled storage (2°C). Pressurization caused a degree of microbiological inactivation, which increased with pressure level and processing time. Pressurization at 400 MPa significantly reduced the total viable count and lactic acid bacteria to the extent that after 20 min no Enterobacteriaceae, Baird Parker flora, or Brochothrix thermosphacta were detected throughout any of the chilled storage periods studied. In general, gram-positive flora was more resistant to pressure than gram-negative flora. The fact that high pressure (400 MPa) causes considerable inactivation of microorganisms could be used to prolong the shelf life of vacuum-prepackaged sliced cooked ham.

Experimental Study of Mechanism of Rock Breakage with High-Pressure Cavitating Water Jets

2011 ◽  
Vol 243-249 ◽  
pp. 2130-2137
Author(s):  
Zhao Long Ge ◽  
Yi Yu Lu ◽  
Ji Ren Tang ◽  
Ke Hu ◽  
Wen Feng Zhang
Keyword(s):  
High Pressure ◽  
Confining Pressure ◽  
Rock Breaking ◽  
Pressure Increase ◽  
Rock Breakage ◽  
Bubble Cloud ◽  
Cubic Curve ◽  
Water Jets ◽  
Erosion Efficiency ◽  
Pump Pressure

To explore the relationship among the erosion ability of high-pressure cavitating water jets, hydraulic parameters and rock nature with a series of experiments relating to the efficiency of rock-breaking with cavitating water jets for different porosity of rock under different confining pressures and pump pressures. The results show that the erosion efficiency (erosion mass and erosion depth) of cavitating water jets is fitted a conic curve with pump pressure and confining pressure. It increases with the pump pressure increases while decreases with the confining pressure increases; the length of the bubble cloud decreases with the confining pressure increase and the length increases with the pump pressure increase, which is accorded with cubic curve. The bubble cloud length influences the rock-breaking efficiency by deciding the valid stand-off distance directly. Under the experimental condition, the cavitation happens once the pump pressure reaches 7MPa, and the cavitating water jets can crushing the sandstones which the uniaxial compressive strength is 96MPa. On the other hand, the porosity of rock is another main factor of rock breakage with high pressure cavitating water jets. The higher the porosity of rock is, the easier the rock can be broken.

Design, Part Load and Transient Operation of Combined Cycle Plants With Water Flashing

1995 ◽  
Author(s):  
P. J. Dechamps
Keyword(s):  
High Pressure ◽  
Steam Generator ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Vapour Phase ◽  
Pressure Level ◽  
Combined Cycle ◽  
Saturated Steam ◽  
Heat Recovery Steam Generator ◽  
Combined Cycles

The last decade has seen remarkable improvement in gas turbine based power generation technologies, with the increasing use of natural gas-fuelled combined cycle units in various regions of the world. The struggle for efficiency has produced highly complex combined cycle schemes based on heat recovery steam generators with multiple pressure levels and possibly reheat. As ever, the evolution of these schemes is the result of a technico-economic balance between the improvement in performance and the increased costs resulting from a more complex system. This paper looks from the thermodynamic point of view at some simplified combined cycle schemes based on the concept of water flashing. In such systems, high pressure saturated water is taken off the high pressure drum and flashed into a tank. The vapour phase is expanded as low pressure saturated steam or returned to the heat recovery steam generator for superheating, whilst the liquid phase is recirculated through the economizer. With only one drum and three or four heat exchangers in the boiler as in single pressure level systems, the plant might have a performance similar to that of a more complex dual pressure level system. Various configurations with flash tanks are studied based on commercially available 150 MW-class E-technology gas turbines and compared with classical multiple pressure level combined cycles. Reheat units are covered, both with flash tanks and as genuine combined cycles for comparison purposes. The design implications for the heat recovery steam generator in terms of heat transfer surfaces are emphasized. Off-design considerations are also covered for the flash based schemes, as well as transient performances of these schemes, because the simplicity of the flash systems compared to normal combined cycles significantly affects the dynamic behaviour of the plant.

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