The Dynamics of High-Speed Sliding Power Collection Systems for Electrically Propelled Vehicles

1974 ◽  
Vol 96 (2) ◽  
pp. 158-162
Author(s):  
J. A. Bain
Keyword(s):  
Surface Roughness ◽  
Contact Force ◽  
High Speed ◽  
Reference Case ◽  
The Third ◽  
Measured Sample ◽  
Force Variation ◽  
Random Irregularity

A method is presented for estimating the contact force variation between a collector brush and a rigid third rail when the third rail has a surface with random irregularity. Results are obtained for a reference case where the third rail roughness is estimated from the roughness of other known surfaces. The surface roughness of an actual commercial third rail is measured and the results are used to estimate the performance of a collector on the measured sample at 300 mph. Conclusions are drawn about the feasibility of power collection at 300 mph.

Computer Evaluation of Controlled Pantographs for Current Collection From Simple Catenary Overhead Equipment at High Speed

1983 ◽  
Vol 105 (4) ◽  
pp. 287-294 ◽  
Author(s):  
T. Vinayagalingam
Keyword(s):  
Contact Force ◽  
High Speed ◽  
Overhead Line ◽  
Combined System ◽  
Current Collection ◽  
Constant Height ◽  
Force Profile ◽  
Force Variation ◽  
Computer Simulation Technique

A digital computer simulation technique is used to study the effects of changing pantograph characteristics upon the quality of current collection from simple catenary overhead equipment at high speed. In particular, the likely benefits to be derived by the use of controlled pantographs are assessed. Pantograph performance is judged on the basis of contact force variation and displacement responses of pantograph and contact wire. These studies have shown that the dynamic displacements of the combined system are determined primarily by the overhead line parameters rather than by the pantograph. At higher speeds droppers in the vicinity of the pantograph slacken and this is seen to influence significantly the contact force profile. On a “constant height” overhead line, the proposed “frame compensated” and “panhead inertia compensated” pantographs do not show any marked improvement in the quality of current collection.

Active Control of a High-Speed Pantograph

1997 ◽  
Vol 119 (1) ◽  
pp. 1-4 ◽  
Author(s):  
D. N. O’Connor ◽  
S. D. Eppinger ◽  
W. P. Seering ◽  
D. N. Wormley
Keyword(s):  
Dynamic Model ◽  
Active Control ◽  
Contact Force ◽  
High Speed ◽  
High Speed Train ◽  
Single Measurement ◽  
Force Variation ◽  
Catenary System ◽  
And Performance ◽  
And Control

The design and performance of an active controller for a pantograph which collects current for a high-speed train are considered. A dynamic model of the pantograph/catenary system is described and control objectives are established. A design which incorporates a frame-actuated controller and requires only a single measurement is described. Over an array of train speeds, the contact force variation with the actively controlled pantograph is 50 percent less than for the equivalent passive pantograph system.

Effect of Design Changes in Railway Catenary-Pantograph Systems on Power Collection at High Speed

1968 ◽  
Vol 90 (4) ◽  
pp. 680-689
Author(s):  
R. T. Gray ◽  
S. Levy ◽  
J. A. Bain ◽  
E. J. Leclerc
Keyword(s):  
Contact Force ◽  
High Speed ◽  
Operating Conditions ◽  
Department Of Transportation ◽  
High Speeds ◽  
Design Changes ◽  
Force Variation ◽  
Suitable System ◽  
The U.S

Using a GE-635 computer program developed for the U.S. Department of Transportation, a study has been made of the effect of changes in the catenary-pantograph system on the quality of power collection at high speeds. The study explored the effect of: (a) Sag between towers, (b) pantograph spacing, (c) stiffness of the tower support, (d) damping and stiffness of the pantograph, (e) stiffness of the contact spring, (f) dropper stiffness, (g) dropper spacing. It was found that all of these have a significant effect on the constancy of the contact force between catenary and pantograph. By proper choice of system constants, the contact force variation can be substantially reduced. A basis is provided for selecting suitable system constants for a given range of operating conditions.

Dynamics of a Power Collector With Friction Dampers

1976 ◽  
Vol 98 (1) ◽  
pp. 306-311 ◽  
Author(s):  
K. Yoshida ◽  
T. Shimogo
Keyword(s):  
Contact Force ◽  
Coulomb Friction ◽  
High Speed ◽  
Equivalent Linearization ◽  
Friction Damper ◽  
Friction Forces ◽  
Friction Dampers ◽  
Force Variation ◽  
Optimal Values ◽  
The Mean

Using the friction damper, the construction of power collector for a very high-speed railway will be considerably simplified. In this paper, the power collector with friction dampers is considered, and its dynamic characteristics are analyzed by the equivalent linearization technique. The main purpose of this paper is to investigate the effects of Coulomb friction forces on the mean squared value of contact force variation between a contactor and a rigid collecting rail with a randomly wavy surface. A numerical example is presented, and the optimal values of Coulomb friction forces which minimize the probability that the contact force becomes negative are found as a result.

Enhancement of EDM Performance by Using Copper-Silver Composite Electrode

2020 ◽  
Vol 38 (9A) ◽  
pp. 1352-1358
Author(s):  
Saad K. Shather ◽  
Abbas A. Ibrahim ◽  
Zainab H. Mohsein ◽  
Omar H. Hassoon
Keyword(s):  
Surface Roughness ◽  
Material Removal Rate ◽  
Material Removal ◽  
High Speed ◽  
Composite Electrode ◽  
Removal Rate ◽  
Pure Copper ◽  
High Speed Steel ◽  
Pulse On Time ◽  
Pulse Off Time

Discharge Machining is a non-traditional machining technique and usually applied for hard metals and complex shapes that difficult to machining in the traditional cutting process. This process depends on different parameters that can affect the material removal rate and surface roughness. The electrode material is one of the important parameters in Electro –Discharge Machining (EDM). In this paper, the experimental work carried out by using a composite material electrode and the workpiece material from a high-speed steel plate. The cutting conditions: current (10 Amps, 12 Amps, 14 Amps), pulse on time (100 µs, 150 µs, 200 µs), pulse off time 25 µs, casting technique has been carried out to prepare the composite electrodes copper-sliver. The experimental results showed that Copper-Sliver (weight ratio70:30) gives better results than commonly electrode copper, Material Removal Rate (MRR) Copper-Sliver composite electrode reach to 0.225 gm/min higher than the pure Copper electrode. The lower value of the tool wear rate achieved with the composite electrode is 0.0001 gm/min. The surface roughness of the workpiece improved with a composite electrode compared with the pure electrode.

Experimental investigation of wall heat transfer due to spray combustion in a high-pressure/high-temperature vessel

2021 ◽  
pp. 146808742110072
Author(s):  
Karri Keskinen ◽  
Walter Vera-Tudela ◽  
Yuri M Wright ◽  
Konstantinos Boulouchos
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
High Pressure ◽  
High Temperature ◽  
High Speed ◽  
Transfer Problem ◽  
Wall Heat Transfer ◽  
Gas Temperature ◽  
Reference Case ◽  
High Pressure High Temperature

Combustion chamber wall heat transfer is a major contributor to efficiency losses in diesel engines. In this context, thermal swing materials (adapting to the surrounding gas temperature) have been pinpointed as a promising mitigative solution. In this study, experiments are carried out in a high-pressure/high-temperature vessel to (a) characterise the wall heat transfer process ensuing from wall impingement of a combusting fuel spray, and (b) evaluate insulative improvements provided by a coating that promotes thermal swing. The baseline experimental condition resembles that of Spray A from the Engine Combustion Network, while additional variations are generated by modifying the ambient temperature as well as the injection pressure and duration. Wall heat transfer and wall temperature measurements are time-resolved and accompanied by concurrent high-speed imaging of natural luminosity. An investigation with an uncoated wall is carried out with several sensor locations around the stagnation point, elucidating sensor-to-sensor variability and setup symmetry. Surface heat flux follows three phases: (i) an initial peak, (ii) a slightly lower plateau dependent on the injection duration, and (iii) a slow decline. In addition to the uncoated reference case, the investigation involves a coating made of porous zirconia, an established thermal swing material. With a coated setup, the projection of surface quantities (heat flux and temperature) from the immersed measurement location requires additional numerical analysis of conjugate heat transfer. Starting from the traces measured beneath the coating, the surface quantities are obtained by solving a one-dimensional inverse heat transfer problem. The present measurements are complemented by CFD simulations supplemented with recent rough-wall models. The surface roughness of the coated specimen is indicated to have a significant impact on the wall heat flux, offsetting the expected benefit from the thermal swing material.

Characteristic properties of AlTiN and TiN coated HSS materials

2015 ◽  
Vol 67 (2) ◽  
pp. 172-180 ◽  
Author(s):  
Mumin Sahin ◽  
Cenk Misirli ◽  
Dervis Özkan
Keyword(s):  
Surface Roughness ◽  
Tensile Strength ◽  
High Speed ◽  
Cutting Tools ◽  
High Speed Steel ◽  
Wear Properties ◽  
Content Type ◽  
X Ray ◽  
Number Of Cycles ◽  
Future Work

Purpose – The purpose of this paper is to examine mechanical and metallurgical properties of AlTiN- and TiN-coates high-speed steel (HSS) materials in detail. Design/methodology/approach – In this study, HSS steel parts have been processed through machining and have been coated with AlTiN and TiN on physical vapour deposition workbench at approximately 6,500°C for 4 hours. Tensile strength, fatigue strength, hardness tests for AlTiN- and TiN-coated HSS samples have been performed; moreover, energy dispersive X-ray spectroscopy and X-ray diffraction analysis and microstructure analysis have been made by scanning electron microscopy. The obtained results have been compared with uncoated HSS components. Findings – It was found that tensile strength of TiAlN- and TiN-coated HSS parts is higher than that of uncoated HSS parts. Highest tensile strength has been obtained from TiN-coated HSS parts. Number of cycles for failure of TiAlN- and TiN-coated HSS parts is higher than that for HSS parts. Particularly TiN-coated HSS parts have the most valuable fatigue results. However, surface roughness of fatigue samples may cause notch effect. For this reason, surface roughness of coated HSS parts is compared with that of uncoated ones. While the average surface roughness (Ra) of the uncoated samples was in the range of 0.40 μm, that of the AlTiN- and TiN-coated samples was in the range of 0.60 and 0.80 μm, respectively. Research limitations/implications – It would be interesting to search different coatings for cutting tools. It could be the good idea for future work to concentrate on wear properties of tool materials. Practical implications – The detailed mechanical and metallurgical results can be used to assess the AlTiN and TiN coating applications in HSS materials. Originality/value – This paper provides information on mechanical and metallurgical behaviour of AlTiN- and TiN-coated HSS materials and offers practical help for researchers and scientists working in the coating area.

scholarly journals Aerodynamic Losses in Turbines with and without Film Cooling, as Influenced by Mainstream Turbulence, Surface Roughness, Airfoil Shape, and Mach Number

2012 ◽  
Vol 2012 ◽  
pp. 1-28 ◽  
Author(s):  
Phil Ligrani
Keyword(s):  
Surface Roughness ◽  
Mach Number ◽  
Film Cooling ◽  
Total Pressure ◽  
High Speed ◽  
Density Ratio ◽  
Aerodynamic Loss ◽  
Pressure Losses ◽  
Loss Coefficients ◽  
Exit Mach Number

The influences of a variety of different physical phenomena are described as they affect the aerodynamic performance of turbine airfoils in compressible, high-speed flows with either subsonic or transonic Mach number distributions. The presented experimental and numerically predicted results are from a series of investigations which have taken place over the past 32 years. Considered are (i) symmetric airfoils with no film cooling, (ii) symmetric airfoils with film cooling, (iii) cambered vanes with no film cooling, and (iv) cambered vanes with film cooling. When no film cooling is employed on the symmetric airfoils and cambered vanes, experimentally measured and numerically predicted variations of freestream turbulence intensity, surface roughness, exit Mach number, and airfoil camber are considered as they influence local and integrated total pressure losses, deficits of local kinetic energy, Mach number deficits, area-averaged loss coefficients, mass-averaged total pressure loss coefficients, omega loss coefficients, second law loss parameters, and distributions of integrated aerodynamic loss. Similar quantities are measured, and similar parameters are considered when film-cooling is employed on airfoil suction surfaces, along with film cooling density ratio, blowing ratio, Mach number ratio, hole orientation, hole shape, and number of rows of holes.

A Comprehensive Study on Surface Roughness in Machining of AISI D2 Hardened Steel

2012 ◽  
Vol 576 ◽  
pp. 60-63 ◽  
Author(s):  
N.A.H. Jasni ◽  
Mohd Amri Lajis
Keyword(s):  
Surface Roughness ◽  
High Speed ◽  
End Milling ◽  
Cutting Speed ◽  
Hardened Steel ◽  
Depth Of Cut ◽  
Feed Speed ◽  
Radial Depth ◽  
Aisi D2 ◽  
Coated Carbide

Hard milling of hardened steel has wide application in mould and die industries. However, milling induced surface finish has received little attention. An experimental investigation is conducted to comprehensively characterize the surface roughness of AISI D2 hardened steel (58-62 HRC) in end milling operation using TiAlN/AlCrN multilayer coated carbide. Surface roughness (Ra) was examined at different cutting speed (v) and radial depth of cut (dr) while the measurement was taken in feed speed, Vf and cutting speed, Vc directions. The experimental results show that the milled surface is anisotropic in nature. Surface roughness values in feed speed direction do not appear to correspond to any definite pattern in relation to cutting speed, while it increases with radial depth-of-cut within the range 0.13-0.24 µm. In cutting speed direction, surface roughness value decreases in the high speed range, while it increases in the high radial depth of cut. Radial depth of cut is the most influencing parameter in surface roughness followed by cutting speed.

Theoretical Surface Roughness Model in High Speed Face Milling

2014 ◽  
Vol 989-994 ◽  
pp. 3331-3334
Author(s):  
Tao Zhang ◽  
Guo He Li ◽  
L. Han
Keyword(s):  
Surface Roughness ◽  
Surface Integrity ◽  
High Speed ◽  
Cutting Parameters ◽  
Angular Speed ◽  
Face Milling ◽  
Advanced Manufacturing ◽  
Roughness Model ◽  
Machined Parts ◽  
Important Object

High speed milling is a newly developed advanced manufacturing technology. Surface integrity is an important object of machined parts. Surface roughness is mostly used to evaluate to the surface integrity. A theoretical surface roughness model for high face milling was established. The influence of cutting parameters on the surface roughness is analyzed. The surface roughness decreases when the cutter radius increases, total number of tooth and rotation angular speed, while it increases with the feeding velocity. The high speed face milling can get a smooth surface and it can replace the grinding with higher efficiency.

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