scholarly journals Investigation on the Strain Distribution in Tube High-Pressure Shearing

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1117
Author(s):  
Jiajie Meng ◽  
Zheng Li ◽  
Ying Liu ◽  
Yebin Zhu ◽  
Shun Wang ◽  
...  
Keyword(s):  
High Pressure ◽  
Strain Distribution ◽  
Cone Angle ◽  
Strain Hardening Exponent ◽  
Theoretical Approaches ◽  
Geometric Factors ◽  
Dead Metal Zone ◽  
Deformation Inhomogeneity ◽  
Advantageous Position ◽  
Wedge Effect

The Finite-element method (FEM) and experiments were used to investigate the geometric factors and material parameter on the strain distribution during tube high-pressure shearing (t-HPS). The results show that t-HPS could be realized successfully either by pressurizing on both ends of the tube, or by pressurizing using the wedge effect; and in both cases, the “dead metal zone” could be found at both ends of the tube. The grain size distribution from the experiment confirmed this strain distribution feature. In the case of t-HPS pressurized using the wedge effect, the half cone angle has little effect on the strain distribution. Decreasing the strain-hardening exponent leads to increased deformation inhomogeneity in both the ideal t-HPS described by theoretical equations and the close to practical t-HPS described by FEM. This feature of t-HPS stands out from other SPD processes like HPT, and makes practical t-HPS behavior more predictable using the analytical formation than any other SPD processes, and places it an advantageous position in understanding the basics of deformation physics through the coupling between practical experiments and theoretical approaches.

Ionic conduction in sodium azide under high pressure: Experimental and theoretical approaches

2018 ◽  
Vol 112 (17) ◽  
pp. 173903 ◽  
Author(s):  
Qinglin Wang ◽  
Yanzhang Ma ◽  
Dandan Sang ◽  
Xiaoli Wang ◽  
Cailong Liu ◽  
...  
Keyword(s):  
High Pressure ◽  
Sodium Azide ◽  
Ionic Conduction ◽  
Theoretical Approaches

Effect of Geometric Parameters on the Performance of a Radial Flow Pressure Exchange Ejector

2010 ◽  
Author(s):  
Muhammad Umar ◽  
Charles A. Garris
Keyword(s):  
High Pressure ◽  
Radial Flow ◽  
Energy Levels ◽  
Cone Angle ◽  
Interface Pressure ◽  
Complex Flow ◽  
Transfer Energy ◽  
Two Fluids ◽  
Flow Pressure ◽  
Pressure Exchange

The “Pressure exchange” is a novel concept in turbomachinery whereby two fluids, at different energy levels, come in direct contact with each other to transfer energy and momentum between them through non-steady interface pressure forces. The rotating jets of the high pressure primary fluid, often referred to as pseudoblades, resemble solid blades on the impeller of a conventional turbomachine. The low pressure secondary fluid, ahead of the pseudoblades, is pressurized by the action of interface pressure forces. The current paper seeks to provide an insight into the complex flow phenomena occurring inside the radial flow pressure exchange ejector. This research presents the results of the first successful numerical simulation to explore the effects of spin angle, rotor cone angle and number of nozzles on the performance of a radial flow pressure exchange ejector. If this new concept is shown to be viable for gas compression at sufficiently high pressure ratios, then, in refrigeration applications, it would enable environmentally benign refrigerants to replace the harmful chlorofluorocarbons (CFC) and reduce the effluence of greenhouse gases. Applications in many other areas, where conventional ejectors are currently used, are also possible.

THREE-DIMENSIONAL SIMULATION OF DEFORMATION FIELDS UNDERNEATH VICKERS INDENTER: EFFECTS OF POWER-LAW PLASTICITY

2010 ◽  
Vol 24 (01n02) ◽  
pp. 238-246 ◽  
Author(s):  
NUWONG CHOLLACOOP ◽  
UPADRASTA RAMAMURTY
Keyword(s):  
Yield Strength ◽  
Strain Hardening ◽  
Power Law ◽  
Strain Distribution ◽  
Three Dimensional ◽  
Strain Hardening Exponent ◽  
Al Alloy ◽  
Element Analysis ◽  
Vickers Indenter ◽  
Experimental Heat

The effects of power-law plasticity (yield strength and strain hardening exponent) on the plastic strain distribution underneath a Vickers indenter was systematically investigated by recourse to three-dimensional finite element analysis, motivated by the experimental macro- and micro-indentation on heat-treated Al - Zn - Mg alloy. For meaningful comparison between simulated and experimental results, the experimental heat treatment was carefully designed such that Al alloy achieve similar yield strength with different strain hardening exponent, and vice versa. On the other hand, full 3D simulation of Vickers indentation was conducted to capture subsurface strain distribution. Subtle differences and similarities were discussed based on the strain field shape, size and magnitude for the isolated effect of yield strength and strain hardening exponent.

Optimization of a High Pressure Swirl Injector by Using Volume-of-Fluid (VOF) Method

2010 ◽  
Author(s):  
Mohammad Rezaeimoghaddam ◽  
Hossein Moin ◽  
M. R. Modarres Razavi ◽  
Mohammad Pasandideh-Fard ◽  
Rasool Elahi
Keyword(s):  
High Pressure ◽  
Stokes Equations ◽  
Cone Angle ◽  
Volume Of Fluid ◽  
Liquid Sheet ◽  
Vof Method ◽  
Geometric Parameters ◽  
Orifice Diameter ◽  
Swirl Chamber ◽  
Pressure Swirl

In this paper, the effects of various geometric parameters of a high pressure swirl Gasoline Direct Injector (GDI) on the injection flow quality are investigated. The two-dimensional axisymmetric Navier-Stokes equations coupled with the Volume-of-Fluid (VOF) method were employed for simulation of the formation mechanism of the liquid film inside the swirl chamber and the orifice hole of the pressure swirl atomizer. To validate the model, results for base injector were compared in the steady state operation with those of available experiments in the literature. Good agreements were obtained for discharge coefficient (Cd) and cone angle (θ) with experimental data. The effects of five characteristic geometric parameters of swirl injectors such as orifice ratio (orifice length to orifice diameter), angle of swirl chamber, orifice diameter, needle lift and needle head angle (assumed to be cone) were investigated. The results show that increasing the swirl chamber angle leads to an increase in mass flow rate and a decrease of the cone angle of liquid sheet. Through extensive simulations, geometric parameters of an optimum injector were obtained.

Pipeline Shore Approach Design: Case Study

2011 ◽  
Author(s):  
Scott Y. McMaster ◽  
Dean R. Campbell ◽  
Eric Jas
Keyword(s):  
High Pressure ◽  
Best Practice ◽  
Large Diameter ◽  
Cost Effective ◽  
Careful Consideration ◽  
Theoretical Approaches ◽  
Heritage Site ◽  
External Impact ◽  
Offshore Industry ◽  
Design Case Study

An insight is provided into the design of a large diameter high pressure gas pipeline shore approach for an LNG project off the coast of North Western Australia. The shore approach is located in a challenging and congested area, within one of Australia’s busiest ports. In close proximity to the pipeline route are two existing high pressure gas pipelines, several major shipping channels, a large spoil ground and environmentally sensitive coral reefs. Throughout the design process, careful consideration has been given to environmental and heritage constraints. In the case of the pipeline shore approach, prevention of coral mortality due to dredging induced turbidity has been a key priority. Ensuring the preservation of the heritage site adjacent to the landfall site has also been a major consideration. This paper describes the numerous challenges faced in designing the pipeline shore approach. A description of the design processes used to develop the secondary stabilisation and accidental external impact designs is provided. The unique methods employed to install the trunkline system across an operating shipping channel are also described. The information provided in this paper can be applied to the design and development of numerous pipeline shore approaches in the future. Individuals interested in pipeline secondary stabilisation, impact protection, shore crossings and pipelay techniques will also find this paper of value. This paper contributes to the technical knowledge base of the offshore industry by displaying the benefits of effectively combining relevant theoretical approaches with state of the art physical model testing methods and best practice installation techniques. This work demonstrates how innovative design practices can be successfully applied to produce a safe, cost effective and robust pipeline shore approach design in a challenging area.

Pressure induced semiconductor–metal phase transition in GaAs: experimental and theoretical approaches

RSC Advances ◽  
2016 ◽  
Vol 6 (12) ◽  
pp. 10144-10149 ◽  
Author(s):  
Jia Wang ◽  
Baojia Wu ◽  
Guozhao Zhang ◽  
Lianhua Tian ◽  
Guangrui Gu ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
First Principles ◽  
Metal Phase ◽  
First Principles Calculations ◽  
Electrical Measurements ◽  
Theoretical Approaches ◽  
Metal Phase Transition

GaAs undergoes a semiconductor–metal transition, which was investigated by in situ electrical measurements and first-principles calculations under a high pressure.

Effects of strain hardenability and strain-rate sensitivity on the plastic flow and deformation homogeneity during equal channel angular pressing

2001 ◽  
Vol 16 (3) ◽  
pp. 856-864 ◽  
Author(s):  
Hyoung Seop Kim ◽  
Sun Ig Hong ◽  
Min Hong Seo
Keyword(s):  
Strain Rate ◽  
Strain Hardening ◽  
Plastic Flow ◽  
Equal Channel Angular Pressing ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity ◽  
Strain Hardening Exponent ◽  
Angular Pressing ◽  
Deformation Inhomogeneity ◽  
Method Analysis

The effects of strain hardenability and strain rate sensitivity on the plastic flow and deformation inhomogeneity during equal channel angular pressing were studied using a finite element method analysis. In this study, perfect plastic nonhardening and rate-insensitive materials, and rate-sensitive materials were considered. In case of the nonhardening and rate-insensitive materials, the deformed geometry was predicted to be quite uniform and homogeneous. Deformation inhomogeneity developed, however, in materials with finite work-hardening exponent and strain-rate sensitivity. The corner gap formed in strain-hardening materials whereas the upper and lower channel gaps formed in strain-rate-sensitive materials. The deformation inhomogeneity was strongly dependent on the relative effects of strain-hardening exponent and strain-rate sensitivity. The predictions on the deformation inhomogeneity and the formation of corner and channel gaps were compatible with the experimental data published in the literature.

scholarly journals CFD simulations of the diesel jet primary atomization from a multihole injector

2017 ◽  
Author(s):  
Charalambos Chasos
Keyword(s):  
High Pressure ◽  
Nozzle Exit ◽  
Cone Angle ◽  
Injection Pressure ◽  
Liquid Jet ◽  
Spray Cone Angle ◽  
Two Phase ◽  
Spray Cone ◽  
Breakup Length ◽  
Jet Breakup

High pressure multi-hole diesel injectors are currently used in direct-injection common-rail diesel engines for the improvement of fuel injection and air/fuel mixing, and the overall engine performance. The resulting spray injection characteristics are dictated by the injector geometry and the injection conditions, as well as the ambient conditions into which the liquid is injected. The main objective of the present study was to design a high pressure multi-hole diesel injector and model the two-phase flow using the volume of fluid (VOF) method, in order to predict the initial liquid jet characteristics for various injection conditions. A computer aided design (CAD) software was employed for the design of the three-dimensional geometry of the assembly of the injector and the constant volume chamber into which the liquid jet emerges. A typical six-hole diesel injector geometry was modelled and the holes were symmetrically located around the periphery of the injector tip. The injector nozzle diameter and length were 0.2 mm and 1 mm, respectively, resulting in a ratio of nozzle orifice length over nozzle diameter L/D = 5. The commercial computational fluid dynamics (CFD) code STAR-CD was used for the generation of the computational mesh and for transient simulations with an Eulerian approach incorporating the VOF model for the two-phase flow and the Rayleigh model for the cavitation phenomenon. Three test cases for increasing injection pressure of diesel injection from the high pressure multi-hole diesel injector into high pressure and high temperature chamber conditions were investigated. From the injector simulations of the test cases, the nozzle exit velocity components were determined, along with the emerging liquid jet breakup length at the nozzle exit. Furthermore, the spray angle was estimated by the average radial displacement of the liquid jet and air mixture at the vicinity of the nozzle exit. The breakup length of the liquid jet and the spray cone angle which were determined from the simulations, were compared with the breakup length and cone angle estimated by empirical equations. From the simulations, it was found that cavitation takes place at the nozzle inlet for all the cases, and affects the fuel and air interaction at the upper area of the spray jet. Furthermore, the spray jet breakup length increases with elapsed time, and when the injection pressure increases both the breakup length and the spray cone angle increase.DOI: http://dx.doi.org/10.4995/ILASS2017.2017.5040

The dead metal zone in high-pressure torsion

2012 ◽  
Vol 67 (4) ◽  
pp. 384-387 ◽  
Author(s):  
Dong Jun Lee ◽  
Eun Yoo Yoon ◽  
Lee Ju Park ◽  
Hyoung Seop Kim
Keyword(s):  
High Pressure ◽  
High Pressure Torsion ◽  
Dead Metal Zone ◽  
The Dead
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