Design evaluation of multiroll mills for small-diameter wire rolling

2001 ◽  
Vol 215 (1) ◽  
pp. 77-86
Author(s):  
K Kuroda ◽  
T Kuboki ◽  
Y Imamura ◽  
C Hayashi
Keyword(s):  
Numerical Experiments ◽  
Laboratory Experiments ◽  
Small Diameter ◽  
Wire Diameter ◽  
Experimental Results ◽  
Design Evaluation ◽  
Dimensional Precision ◽  
Roll Mill ◽  
Rolled Wire ◽  
Comprehensive Study

A comprehensive study on the evaluation of mill designs was carried out for three types of multiroll mill for wire rolling by using both prototype mills and numerical experiments. The laboratory experiments were carried out in order to examine both the deformation and loading characteristics of two-, three- and four-roll mills using a set of rolls of the same diameter. As a result, the data allow a direct comparison of the rolling characteristics among the three types of mill, which is not found in previous work. The analytical results showed a good matching with the experimental results, and evaluation was then carried out on the three mills. It has been found that the four-roll mill ensures the highest reduction and the two-roll mill the lowest reduction under the restriction that certain dimensional precision of the rolled wire be maintained. This tendency becomes greater as wire diameter decreases and in practice it is recommended that a four-roll mill equipped with small-diameter rolls be used when rolling small-diameter wire. As regarding the loading characteristics, similar conclusions apply. Finally, domains were determined where four-roll mills show their marked superiority.

Characteristics of Hydraulic Shock Waves in an Inclined Chute Contraction - Experiments

2009 ◽  
Vol 25 (1) ◽  
pp. 129-136 ◽  
Author(s):  
C.-D. Jan ◽  
C.-J. Chang ◽  
J.-S. Lai ◽  
W.-D. Guo
Keyword(s):  
Experimental Data ◽  
Shock Waves ◽  
Froude Number ◽  
Inclination Angle ◽  
Laboratory Experiments ◽  
Deflection Angle ◽  
Experimental Results ◽  
Regression Analyses ◽  
Hydraulic Shock ◽  
Empirical Relations

AbstractThis paper presents the experimental results of the characteristics of hydraulic shock waves in an inclined chute contraction with consideration of the effects of sidewall deflection angle φ, bottom inclination angle θ and approach Froude number Fr0. Seventeen runs of laboratory experiments were conducted in the range of 27.45° ≤φ ≤ 40.17°, 6.22° ≤ θ ≤ 25.38° and 1.04 ≤ Fr0 ≤ 3.51. Based on the experimental data, three empirical dimensionless relations for the shock angle, maximum shockwave height, and corresponding position of maximum shockwave were obtained by regression analyses, respectively. These empirical relations would be useful for hydraulic engineers in designing chute contraction structures.

PC-Based Computer Modeling of Combustion Processes

1999 ◽  
Author(s):  
Greg W. Gmurczyk ◽  
Ashwani K. Gupta
Keyword(s):  
Numerical Simulations ◽  
Computer Modeling ◽  
Numerical Experiments ◽  
Laboratory Experiments ◽  
Combustion Process ◽  
Numerical Algorithms ◽  
Computer Hardware ◽  
Simplifying Assumptions ◽  
High Level ◽  
Analytical Approaches

Abstract Constant and significant progress in both computer hardware and numerical algorithms, in recent years, have made it possible to investigate complex phenomena in engineering systems using computer modeling and simulations. Advanced numerical simulations can be treated as an extension of traditional analytical-theoretical analyses. In such cases, some of the simplifying assumptions can usually be dropped and the nonlinear interactions between various processes can be captured. One of the most complex engineering processes encountered in industry is a combustion process utilized either for power/thrust generation or incineration. However, even nowadays, because of the high level of complexity of the general problem of a combustion process in practical systems, it is not currently possible to simulate directly all the length and time scales of interest. Simplifying assumptions still need to be made, but they can be less drastic than in analytical approaches. Therefore, another view of numerical simulations is as a tool to simulate idealized systems and conduct numerical experiments. Such numerical experiments can be complementary to laboratory experiments and can also provide more detailed, nonintrusive diagnostics. Therefore, simulations, along with theory and laboratory experiments, can provide a more complete picture and better understanding of a combustion process. As an example of computer modeling of industrial combustion systems, an enclosed spray flame was considered. Such a flame can frequently be encountered in power generation units, turbine engines, and incinerators. Both the physical and mathematical models were formulated based on data from earlier laboratory studies and results obtained for open air spray flames. The purpose of this study was to use those data as model input to predict the characteristics of a confined flame and provide a means of optimizing the system design with a PC computer.

scholarly journals A MODEL FOR BREACH GROWTH IN A DIKE-BURST

1988 ◽  
Vol 1 (21) ◽  
pp. 140 ◽  
Author(s):  
Paul J. Visser
Keyword(s):  
Mathematical Model ◽  
The Netherlands ◽  
Laboratory Experiments ◽  
Suspended Load ◽  
Experimental Results ◽  
Sand Transport ◽  
Model Predictions ◽  
Pumped Storage

A mathematical model for sand-dike breach erosion is presented. The heart of the model is a modified Bagnold (1963) energetics—based sand transport conception combined with a simplified Galappatti and Vreugdenhil (1985) pick up mechanism for the suspended load. The model has been tested to three laboratory experiments. The agreement between model predictions and experimental results is surprisingly good. Prototype calculations are presented for the 73 m high sand—dike of a proposed pumped—storage plant in the Netherlands.

Accelerated Cooling of Optical Fiber

1989 ◽  
Vol 172 ◽  
Author(s):  
S. Kyriacou ◽  
C. E. Polymeropoulos ◽  
V. Sernas
Keyword(s):  
Optical Fiber ◽  
Gas Flow ◽  
Small Diameter ◽  
Experimental Results ◽  
Accelerated Cooling ◽  
Fiber Motion

AbstractA novel apparatus for accelerated cooling of optical fiber has been used at different fiber speeds using Nitrogen and Helium as the cooling gases. The gas flow was counter to the direction of the fiber motion inside a small diameter tube. The experimental results show significant improvement over natural cooling, as well as over available transverse cooling.

Research of Dinosaurs Weathering Mechanism in Zhucheng Shandong

2015 ◽  
Vol 723 ◽  
pp. 757-762 ◽  
Author(s):  
Shang Kun Zhang ◽  
Sheng Xian Du ◽  
Xue Feng Yu ◽  
Guo Rong Zhang ◽  
Xiang Yu Luo ◽  
...  
Keyword(s):  
Water Temperature ◽  
Numerical Experiments ◽  
Laboratory Experiments ◽  
Reference Value ◽  
Scientific Basis ◽  
Geological Heritage ◽  
Physical Models ◽  
Process Water ◽  
Excavation Process ◽  
Weathering Process

In recent years, more and more domestic and international dinosaur fossils geological heritage were found, and many dinosaur fossils severe weathering within a few years after excavation.This study were based on Zhucheng dinosaur fossils ,the research of weathering mechanism of dinosaur fossils were from aspects of physical - mechanical characteristics.Means of laboratory experiments, physical models, theories and numerical experiments were used to explores the effect of weathering by the factors of excavation process, water, temperature , acidic substances and other factors on dinosaur fossils and relics.The results reveal the physical destruction of Shandong Zhucheng dinosaur fossils in the mechanism and characteristics of weathering process can provide theoretical and scientific basis for the protection of fossils, and other parts of the mechanism of weathering and protection of dinosaur fossils study provides reference value.

Numerical experiments on two-dimensional foam

1992 ◽  
Vol 241 ◽  
pp. 233-260 ◽  
Author(s):  
Thomas Herdtle ◽  
Hassan Aref
Keyword(s):  
Initial Data ◽  
Analytical Solutions ◽  
Numerical Experiments ◽  
Laboratory Experiments ◽  
Evolution Equations ◽  
Two Dimensional ◽  
Von Neumann ◽  
Cpu Time ◽  
Statistical Evolution ◽  
Physical Principles

The statistical evolution of a two-dimensional polygonal, or ‘dry’, foam during diffusion of gas between bubbles lends itself to a very simple mathematical description by combining physical principles discovered by Young. Laplace, Plateau, and von Neumann over a period of a century and a half. Following a brief review of this ‘canonical’ theory, we report results of the largest numerical simulations of this system undertaken to date. In particular, we discuss the existence and properties of a scaling regime, conjectured on the basis of laboratory experiments on larger systems than ours by Glazier and coworkers, and corroborated in computations on smaller systems by Weaire and collaborators. While we find qualitative agreement with these earlier investigations, our results differ on important, quantitative details, and we find that the evolution of the foam, and the emergence of scaling, is very sensitive to correlations in the initial data. The largest computations we have performed follow the relaxation of a system with 1024 bubbles to one with O(10), and took about 30 hours of CPU time on a Cray-YMP supercomputer. The code used has been thoroughly tested, both by comparison with a set of essentially analytic results on the rheology of a monodisperse-hexagonal foam due to Kraynik & Hansen, and by verification of certain analytical solutions to the evolution equations that we found for a family of ‘fractal foams’.

Characteristics of Hydraulic Shock Waves in an Inclined Chute Contraction - Experiments

2009 ◽  
Vol 25 (2) ◽  
pp. 129-136 ◽  
Author(s):  
C.-D. Jan ◽  
C.-J. Chang ◽  
J.-S. Lai ◽  
W.-D. Guo
Keyword(s):  
Experimental Data ◽  
Shock Waves ◽  
Froude Number ◽  
Inclination Angle ◽  
Laboratory Experiments ◽  
Deflection Angle ◽  
Experimental Results ◽  
Regression Analyses ◽  
Hydraulic Shock ◽  
Empirical Relations

AbstractThis paper presents the experimental results of the characteristics of hydraulic shock waves in an inclined chute contraction with consideration of the effects of sidewall deflection angle φ, bottom inclination angle θ and approach Froude number Fr0. Seventeen runs of laboratory experiments were conducted in the range of 27.45° ≤φ≤ 40.17°, 6.22°≤ θ ≤ 25.38° and 1.04 ≤ Fr0 ≤ 3.51. Based on the experimental data, three empirical dimensionless relations for the shock angle, maximum shockwave height, and corresponding position of maximum shockwave were obtained by regression analyses, respectively. These empirical relations would be useful for hydraulic engineers in designing chute contraction structures.

scholarly journals A COMPREHENSIVE STUDY OF THE STABILITY OF LATERAL ROCKS WITH A SUPPLE SUPPORT

World Science ◽  
2020 ◽  
Vol 1 (1(53)) ◽  
pp. 4-17 ◽  
Author(s):  
Iordanov I. V. ◽  
Simonova Yu. I. ◽  
Polozhy A. V. ◽  
Podkopayev Ye. S. ◽  
Skyrda A. Ye. ◽  
...  
Keyword(s):  
Strain State ◽  
Laboratory Experiments ◽  
Flexible Structures ◽  
Crushed Rock ◽  
Beam Model ◽  
Coal Pillars ◽  
The Stability ◽  
Stratified Rock ◽  
Roof Rocks ◽  
Comprehensive Study

A complex of analytical studies of the stability of lateral rocks with a supple support, where the coal seam roof was a beam model, some laboratory experiments on samples made from optical and equivalent materials, as well as some mine experiments were was carried out. As a result of the studies, it was found that the stability of lateral rocks with a supple support of crushed rock depended on the compaction of the backfill array on which the roof rocks were based. It was experimentally proved that with external force, the coefficient of compaction of the backfill array changes according to the hyperbolic dependence, the maximum values of which were determined as a result of compaction of the supple support consisting of heterogeneous fractions of the starting material of a certain bulk density. The change in the stress-strain state of the lateral rocks in the coal array with a roadway depended on the bending stiffness of the stratified rock mass and the parameters of flexible structures used to support the roadway. When supporting the roadways with supple support structures, the convergence of the lateral rocks on the contour of the stoop roadway was observed exponentially until the support was completely compressed, while supporting the roadways with coal pillars, the displacement of the rocks on the contour of the roadway increased having linear dependence due to the destruction of the pillar. The stability of the lateral rocks, which determines the operational state of the excavation roadways, was ensured by the use of supple supports or stowing the mined-out space, taking into account the reasonable granulometric content of crushed rock, which ensured the maximum values of the compaction coefficient of the backfill array when the roof and coal seat got deformed.

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