Numerical Study of the Process of Hot Helical Rolling of Hollow Billets with a Small-Diameter Bottom

Metallurgist ◽  
2020 ◽  
Vol 64 (7-8) ◽  
pp. 839-847
Author(s):  
V. V. Kulteshova ◽  
A. V. Ivanov ◽  
I. V. Zavora
Keyword(s):  
Numerical Study ◽  
Small Diameter ◽  
Helical Rolling ◽  
Hollow Billets

scholarly journals Experimental and Numerical Study of Cold Helical Rolling of Small-Diameter Steel Balls

2021 ◽  
Author(s):  
Shengqiang Liu ◽  
Jinping Liu ◽  
Hao Xu ◽  
Zhipeng Wang ◽  
Jinxia Shen ◽  
...  
Keyword(s):  
Work Hardening ◽  
Fe Simulation ◽  
Numerical Study ◽  
Rolling Force ◽  
Effective Strain ◽  
Small Diameter ◽  
Helical Rolling ◽  
Forming Process ◽  
Cold Forming ◽  
Steel Balls

Abstract Cold helical rolling (CHR) is one of the most effective ways to produce small-diameter steel balls. In this study, one kind of work hardening model was established and implemented into Simufact 15.0 to investigate the work hardening phenomenon in the cold forming process. Firstly, based on the helical rolling theory, a set of finite element (FE) simulations was developed. The influence of CHR parameters, including the starting height of convex rib, forming area length, and rolling inclination angle, on the forming process was studied via simulation. Furtherly, the CHR process experiments and FE simulation were carried out , the results showed that the FE simulation was in good agreement with the experimental results, and consistent with the predicted value of the theoretical calculation. Finally, the evolution of effective strain, effective stress, rolling force, work hardening and microstructure during the cold helical rolling of Φ 5.12 mm steel balls was investigated via FE. As result, the evolution trend of hardness was consistent with that of dislocation density, indicating that the model is credible. Besides, the microstructure of the steel ball at different positions further verified this.

scholarly journals Numerical Study of Plasmon Resonance Silver Nanoparticles Coated Polyvinyl Alcohol (PVA) using Bohren-Huffman-Mie Approximation

2016 ◽  
Vol 1 ◽  
Author(s):  
Dede Djuhana
Keyword(s):  
Silver Nanoparticles ◽  
Polyvinyl Alcohol ◽  
Numerical Study ◽  
Large Diameter ◽  
Small Diameter ◽  
Resonant Mode ◽  
Major Peak ◽  
Ag Nps ◽  
Quadrupole Mode ◽  
Minor Peak

<p class="TTPAbstract">In this study, we have investigated the LSPR spectra of the silver nanoparticles (Ag-NPs) coated by polyvinyl alcohol (PVA) by means of a numerical study using Bohren-Huffman-Mie (BHMie) approximation. The LSPR of Ag-NPs shifted to red-shift as the diameter size of Ag-NPs and the thickness of PVA increased. The peak of the LSPR spectra exponentially increased as the thickness increased. Interestingly, there have three characteristic of the LSPR spectra, small, intermediate, and large diameter. In small diameter, the dipole resonant mode contributed to the LSPR spectra while in large diameter, the LSPR spectra originated from the quadrupole resonant mode. In contrast to intermediate diameter, the LSPR spectra originated from the competition between the dipole and the quadrupole mode. For this reason, at small and large diameter the LSPR peak has one peak and increased then until a certain thickness showed constant. Different at intermediate diameter, the LSPR peak appeared more one peak with major peak increased then until a certain thickness trend to decrease and minor peak followed at small diameter behavior.</p>

The Plane Parallel Flow of a Binary Mixture of Fluids

1981 ◽  
Vol 48 (4) ◽  
pp. 707-716
Author(s):  
L. M. Srivastava ◽  
V. P. Srivastava
Keyword(s):  
Binary Mixture ◽  
Particle Deposition ◽  
Numerical Study ◽  
Infinite Plate ◽  
Small Diameter ◽  
Hankel Transform ◽  
Physical Importance ◽  
Strong Motivation ◽  
Insight Into ◽  
Made In

The flow of a binary mixture of chemically inert incompressible, Newtonian fluids over an infinite plate, set into motion in its plane by impulse and by oscillation, is studied. The binary mixture consists of (i) two different viscous density nonstratified fluids, and (ii) two different viscous density stratified fluids. The exact solutions are obtained using two methods, (i) Laplace transform and (ii) Hankel transform. To further study the velocities and the wall shear stress, asymptotic expansion are found for small and large times. Some other results of physical importance such as results for noninteracting fluids, strongly interacting fluids, and extremely different fluids are also derived and compared analytically with other results. Finally, to gain an insight into the patterns of the flow, numerical study of the results has been made in detail using digital computer. A strong motivation of the present analysis has been the hope that such a theory of fluids is useful in providing some insight in rheological properties of complex fluids as polymers, liquid crystals and, in particular, blood in the vessels of small diameter. Also the theory of fluids might provide an improved understanding of such diverse subjects as diffusion of proteins, swimming of micro-organism and particle deposition in respiratory tract.

Failure of X52 Wrinkled Pipelines Subjected to Monotonic Axial Deformation

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Y. Zhang ◽  
S. Das
Keyword(s):  
Parametric Study ◽  
Numerical Study ◽  
Numerical Technique ◽  
Small Diameter ◽  
Full Scale ◽  
Thickness Ratio ◽  
Axial Deformation ◽  
Cross Sectional ◽  
Full Scale Tests ◽  
Internal Pressures

This study was undertaken to investigate and understand the behavior of a wrinkled energy pipeline when subjected to sustained monotonic axial compressive deformation. This study involved both experimental and numerical investigations. Two full-scale laboratory tests with moderate and high internal pressures on X52 grade steel pipes with a diameter-to-thickness ratio of 45 show that this pipeline is extremely ductile and did not rupture under axisymmetric compressive axial deformation. However, they fail due to the excessive cross-sectional deformation and the final deformed shape looks like an accordion due to the formation of multiple wrinkles. Subsequently, a detailed parametric study using a numerical technique was undertaken to determine the failure condition and failure mode of this pipeline for various realistic internal pressures and diameter-to-thickness ratios. A nonlinear finite element method was used for the numerical study. The numerical model was validated with the data obtained from the two full-scale tests. The parametric study shows that the X52 linepipe loses its integrity due to the rupture in the pipe wall if the internal pressure is low and/or if the pipe has a small diameter-to-thickness ratio. This paper presents and discusses the results obtained both from the experimental and numerical parametric studies.

Innovative Equipment for Producing Cost-Effective Hollow Billets for Mechanical-Engineering Parts of Small Diameter

Metallurgist ◽  
2017 ◽  
Vol 61 (3-4) ◽  
pp. 217-222 ◽  
Author(s):  
B. A. Romantsev ◽  
Yu. V. Gamin ◽  
A. V. Goncharuk ◽  
A. S. Aleshchenko
Keyword(s):  
Mechanical Engineering ◽  
Small Diameter ◽  
Cost Effective ◽  
Hollow Billets

scholarly journals Numerical Study of Plasmon Resonance Silver Nanoparticles Coated Polyvinyl Alcohol (PVA) using Bohren-Huffman-Mie Approximation

2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Dede Djuhana
Keyword(s):  
Silver Nanoparticles ◽  
Polyvinyl Alcohol ◽  
Numerical Study ◽  
Large Diameter ◽  
Small Diameter ◽  
Resonant Mode ◽  
Major Peak ◽  
Ag Nps ◽  
Quadrupole Mode ◽  
Minor Peak

<p class="TTPAbstract">In this study, we have investigated the LSPR spectra of the silver nanoparticles (Ag-NPs) coated by polyvinyl alcohol (PVA) by means of a numerical study using Bohren-Huffman-Mie (BHMie) approximation. The LSPR of Ag-NPs shifted to red-shift as the diameter size of Ag-NPs and the thickness of PVA increased. The peak of the LSPR spectra exponentially increased as the thickness increased. Interestingly, there have three characteristic of the LSPR spectra, small, intermediate, and large diameter. In small diameter, the dipole resonant mode contributed to the LSPR spectra while in large diameter, the LSPR spectra originated from the quadrupole resonant mode. In contrast to intermediate diameter, the LSPR spectra originated from the competition between the dipole and the quadrupole mode. For this reason, at small and large diameter the LSPR peak has one peak and increased then until a certain thickness showed constant. Different at intermediate diameter, the LSPR peak appeared more one peak with major peak increased then until a certain thickness trend to decrease and minor peak followed at small diameter behavior.</p>

Critical Mass Flow Rate Through Capillary Tubes

2010 ◽  
Author(s):  
A. Nouri-Borujerdi ◽  
P. Javidmand
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Numerical Study ◽  
Critical Mass ◽  
Small Diameter ◽  
Critical Conditions ◽  
Tube Length ◽  
Capillary Tubes ◽  
Drift Flux Model

This paper presented a numerical study that predicts critical mass flow rate, pressure, vapor quality, and void fraction along a very long tube with small diameter or capillary tub under critical condition by the drift flux model. Capillary tubes are simple expansion devices and are necessary to design and optimization of refrigeration systems. Using dimensional analysis by Buckingham’s π theory, some generalized correlations are proposed for prediction of flow parameters as functions of flow properties and tube sizes under various critical conditions. This study is performed under the inlet pressure in the range of 0.8 ≤ pin ≤ 1.5Mpa, subcooling temperature between 0 ≤ ΔTsub ≤ 10 °C. The tube diameter is in the range of 0.5 ≤ D ≤ 1.5mm and tube length between 1 ≤ L ≤ 2m for water, ammonia, refrigerants R-12, R-22 and R-134 as working fluids. Comparison between the results of the present work and some experimental data indicates a good agreement. Cluster of data close to the fitted curves also shows satisfactory results.

Development of a new class of precast concrete pipes - a numerical evaluation

2007 ◽  
Vol 34 (7) ◽  
pp. 870-884 ◽  
Author(s):  
H El Naggar ◽  
E N Allouche ◽  
M H. El Naggar
Keyword(s):  
Numerical Study ◽  
Precast Concrete ◽  
Small Diameter ◽  
Added Value ◽  
Element Analysis ◽  
Fibre Optics ◽  
New Class ◽  
Concrete Pipes ◽  
Concrete Pipe ◽  
Conduit System

The precast concrete pipe industry is in continuous pursuit to add value to its products to strengthen its market competitiveness against other pipe products. The research reported in this paper aimed at developing a new class of precast concrete pipes that will provide added value to the final user in comparison with existing products. The technology developed by the authors consists of lenses of a porous material that are used to create "conduits" within the wall of a precast concrete pipe, which are continuous across adjacent segments. These conduits can accommodate telecommunication lines (i.e., fibre optics) and other small diameter utilities. The concrete pipe provides protection for the smaller conduits while conserving underground right-of-way space. This paper describes the results of an extensive numerical study undertaken to evaluate the technical viability of the proposed conduit system. Key words: precast concrete pipe, cellular concrete pipe, finite element analysis, conduit system.

Numerical Study of Shear-Induced Heating in High-Speed Nozzle Flow of Liquid Monopropellant

1998 ◽  
Vol 120 (1) ◽  
pp. 58-64 ◽  
Author(s):  
X. Shi ◽  
O. M. Knio ◽  
J. Katz
Keyword(s):  
Wall Temperature ◽  
High Speed ◽  
Numerical Study ◽  
Small Diameter ◽  
Numerical Schemes ◽  
Axisymmetric Nozzle ◽  
Wall Boundary Layer ◽  
Speed Flow ◽  
Prandtl Numbers ◽  
Temperature Dependent Properties

A numerical study is performed which focuses on peak temperatures experienced by a liquid monopropellant during high-speed injection in a small-diameter nozzle. Attention is focused on short-duration injection during which the nozzle wall boundary layer is predominantly laminar. An unsteady ID analysis of the temperature distribution associated with sudden fluid acceleration over a flat insulated boundary is first conducted. Expressions are provided which relate the normalized peak wall temperature to the prevailing Eckert and Prandtl numbers. Results reveal a quadratic dependence of the normalized wall temperature on impulse velocity, and a nonlinear variation with Prandtl number. Next, simulation of high-speed flow in an axisymmetric nozzle is performed. The numerical schemes are based on finite-difference discretization of a vorticity-based formulation of the mass, momentum, and energy conservation equations. Implementation of the numerical schemes to flow of LP 1846 in a 4 mm diameter nozzle indicates that preignition is likely to occur for velocities higher than 200 m/s. The effects of wall heat transfer and temperature-dependent properties are also discussed.

Sign in / Sign up

Export Citation Format

Share Document