Control of Rapid Transit Propulsion System Noise

1984 ◽  
Vol 106 (2) ◽  
pp. 270-277
Author(s):  
P. J. Remington ◽  
N. R. Dixon
Keyword(s):  
High Speed ◽  
Propulsion System ◽  
Laboratory Model ◽  
Rapid Transit ◽  
Blade Passage ◽  
Community Noise ◽  
System Noise ◽  
Cooling Fan ◽  
Urban Rail ◽  
Noise Impact

An extensive series of diagnostic measurements was carried out on an urban rail propulsion system of the type that was found to have the greatest community noise impact. At high speed, 3000 to 4000 rpm, the fan dominates all other sources by 10–15 dBA. At low speed, 1000 to 1500 rpm, fan, gears, and drive motors make comparable noise. A series of tests on a laboratory model of the fan/end housing of a Westinghouse 1447 propulsion motor showed that by modifying the geometry of the end housing posts and reducing the diameter of the cooling fan, the tone at the blade passage frequency was virtually eliminated. In addition, the overall noise was reduced by over 10 dBA while the same airflow was maintained through the fan. When these treatments were applied to the motor itself, it was possible to maintain the same airflow as in the unmodified motor by redesigning the grill over the inlet at the commutator end of the motor. Noise reductions, however, were not as significant as in the laboratory model. Although the blade passage tone was virtually eliminated, overall noise reduction was in the 3 to 6 dBA range, depending on the combination of treatments used.

Integrated Vehicle Comparison of Turbo-Ramjet Engine and Pulsed Detonation Engine

2002 ◽  
Vol 125 (1) ◽  
pp. 257-262 ◽  
Author(s):  
T. Kaemming
Keyword(s):  
Life Cycle Cost ◽  
High Speed ◽  
Fuel Efficiency ◽  
Pressure Rise ◽  
Propulsion System ◽  
Cross Sectional ◽  
Pulsed Detonation Engine ◽  
Pulsed Detonation ◽  
Large Matrix ◽  
Detonation Engine

The pulsed detonation engine (PDE) is a unique propulsion system that uses the pressure rise associated with detonations to efficiently provide thrust. A study was conducted under the direction of the NASA Langley Research Center to identify the flight applications that provide the greatest potential benefits when incorporating a PDE propulsion system. The study was conducted in three phases. The first two phases progressively screened a large matrix of possible applications down to three applications for a more in-depth, advanced design analysis. The three applications best suited to the PDE were (1) a supersonic tactical aircraft, (2) a supersonic strike missile, and (3) a hypersonic single-stage-to-orbit (SSTO) vehicle. The supersonic tactical aircraft is the focus of this paper. The supersonic, tactical aircraft is envisioned as a Mach 3.5 high-altitude reconnaissance aircraft with possible strike capability. The high speed was selected based on the perceived high-speed fuel efficiency benefits of the PDE. Relative to a turbo-ramjet powered vehicle, the study identified an 11% to 21% takeoff gross weight (TOGW) benefit to the PDE on the baseline 700 n.mi. radius mission depending on the assumptions used for PDE performance and mission requirements. The TOGW benefits predicted were a result of the PDE lower cruise specific fuel consumption (SFC) and lower vehicle supersonic drag. The lower vehicle drag resulted from better aft vehicle shaping, which was a result of better distribution of the PDE cross-sectional area. The reduction in TOGW and fuel usage produced an estimated 4% reduction in life cycle cost for the PDE vehicle. The study also showed that the simplicity of the PDE enables concurrent engineering development of the vehicle and engine.

scholarly journals Health co-benefits in mortality avoidance from implementation of the mass rapid transit (MRT) system in Kuala Lumpur, Malaysia

2016 ◽  
Vol 31 (1) ◽  
Author(s):  
Soo Chen Kwan ◽  
Marko Tainio ◽  
James Woodcock ◽  
Jamal Hisham Hashim
Keyword(s):  
Transport Infrastructure ◽  
Rapid Transit ◽  
Kuala Lumpur ◽  
First Line ◽  
Potential Health ◽  
Urban Rail ◽  
Infrastructure Project ◽  
Local Transport ◽  
Change Mitigation ◽  
Mass Rapid Transit

AbstractThe mass rapid transit (MRT) is the largest transport infrastructure project under the national key economic area (NKEA) in Malaysia. As urban rail is anticipated to be the future spine of public transport network in the Greater Kuala Lumpur city, it is important to mainstream climate change mitigation and public health benefits in the local transport development. This study quantifies the health co-benefits in terms of mortality among the urbanites when the first line of the 150 km MRT system in Kuala Lumpur commences by 2017.Using comparative health risk assessment, we estimated the potential health co-benefits from the establishment of the MRT system. We estimated the reduced COA total of 363,130 tonnes of COThe implementation of the MRT system in Greater Kuala Lumpur could bring substantial health co-benefits to both the general population and the MRT users mainly from the avoidance of mortality from traffic injuries.

scholarly journals The Behavior of Jet Currents over a Continental Slope Topography with a Possible Application to the Northern Current

2005 ◽  
Vol 35 (5) ◽  
pp. 790-810 ◽  
Author(s):  
M. M. Flexas ◽  
G. J. F. van Heijst ◽  
R. R. Trieling
Keyword(s):  
High Speed ◽  
Bottom Topography ◽  
Laboratory Model ◽  
Topographic Effects ◽  
Topographic Slope ◽  
Eddy Formation ◽  
Slow Flows ◽  
Bottom Depth ◽  
Source Sink ◽  
Northern Current

Abstract The Northern Current is a slope current in the northwest Mediterranean that shows high mesoscale variability, generally associated with meander and eddy formation. A barotropic laboratory model of this current is used here to study the role of the bottom topography on the current variability. For this purpose, a source–sink setup in a cylindrical tank placed on a rotating table is used to generate an axisymmetric barotropic current. To study inviscid topographic effects, experiments are performed over a topographic slope and also over a constant-depth setup, the latter being used as a reference for the former. With the aim of obtaining a fully comprehensive view of the vorticity balance at play, the flow may be forced in either azimuthal direction, leading to a “westward” prograde current (similar to the Northern Current) or an “eastward” retrograde current. For slow flows, eastward and westward currents showed similar patterns, dominated by Kelvin–Helmholtz-type instabilities. For high-speed flows, eastward and westward currents showed very different behavior. In eastward currents, the variability is observed to concentrate toward the center of the jet and shows strong meandering formation. Westward currents, instead, showed major variability toward the edges of the jet, together with a strong variability over the uppermost slope, which has been associated here with a topographic Rossby wave trapped over the shelf break. The differences between eastward and westward jets are explained through the balance between shear-induced and topographically induced vorticity at play in each case. Moreover, a model of jets over a beta plane is successfully applied here, allowing its extension to any ambient potential vorticity gradient caused either by latitudinal or bottom depth changes.

High Speed Locomotive Development: A European Experience

2010 ◽  
Author(s):  
Janis Vitins
Keyword(s):  
Power Unit ◽  
High Speed ◽  
Propulsion System ◽  
European Experience ◽  
History Of ◽  
And Performance

Europe has a long history of high speed locomotive and power unit development. This paper focuses on these developments in Sweden, Germany, Switzerland and Spain starting from high speed locomotives for 125 mph and ending with the AVE S112 high speed power unit for 206 mph. The major technical objectives starting in the 1970’s were to increase the speed and performance, while reducing the axle load from typically 21t at 125 mph to 17t at ≥ 156 mph. Developments of the propulsion system and vehicle concepts took place in many incremental steps, constantly improving the performance of high speed services. It is shown how American high speed locomotives relate to these developments and how one can learn from the European experience going forward.

Determinants of Train Service Costs in Metro Operations

2015 ◽  
Vol 2534 (1) ◽  
pp. 31-37 ◽  
Author(s):  
Ruben Brage-Ardao ◽  
Daniel J. Graham ◽  
Richard J. Anderson
Keyword(s):  
High Speed ◽  
Returns To Scale ◽  
Relative Weight ◽  
Rolling Stock ◽  
Substitution Effects ◽  
Passenger Rail ◽  
Operation Costs ◽  
Urban Rail ◽  
Metro Systems ◽  
The Cost

Research about service operation costs in the rail sector has usually focused on freight, high-speed, or national passenger rail, but has seldom included the study of the cost of urban rail (metro) rapid transit. This study analyzed the determinants of train service costs for a panel of 24 metro systems worldwide. The study used econometric modeling to assess the relative weight of each factor. Wages and electricity prices and consumption were found to have statistically significant elasticities and evidence of potential substitution effects between factors. Other factors, such as driver productivity, network length, percentage of rolling stock with air conditioning, and rolling stock age, also showed statistically significant elasticities. The study found evidence of strong returns to density and returns to scale in the provision of train service outputs (for example, car kilometers, passenger journeys, and train hours).

Gas Turbine Propulsion for High-Speed Railcars

1967 ◽  
Author(s):  
P. B. Garner ◽  
W. L. Hull
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
High Speed ◽  
Long Island ◽  
Experimental Tests ◽  
Propulsion System ◽  
Drive System ◽  
Market Potential ◽  
Demonstration Program ◽  
Gas Turbine Power Plant

Experimental tests of a turbine-powered, self-propelled, high-speed railcar are presently being conducted on a section of the Long Island Railroad. This paper describes the railcar, the unique gas turbine power plant and mechanical drive system, and the expected railcar performance. The objectives of the demonstration program, the merits of the selected turbomechanical drive system, and the market potential for production turbine-powered railcars are discussed. A summary of test experience to date and a preview of propulsion-system innovations that may be tested in follow-on programs are presented.

Laser Transit Anemometry Investigation of a High Speed Centrifugal Compressor

1989 ◽  
Author(s):  
David Japikse ◽  
David M. Karon
Keyword(s):  
Experimental Investigation ◽  
Secondary Flow ◽  
Centrifugal Compressor ◽  
Turbulence Intensity ◽  
High Speed ◽  
Flow Regimes ◽  
Compressor Stage ◽  
Blade Passage ◽  
Centrifugal Compressor Stage

A detailed experimental investigation of a small centrifugal compressor stage has been completed using laser transit anemometry. Measurements at the inlet and discharge of an impeller have been made while recording data relative to a blade passage. Classical primary and secondary flow regimes within the rotor have been shown plus several compact “cell-like” regions. Various components of velocity and turbulence intensity are presented. This study has demonstrated the capability of using the laser transit anemometer for investigating the kinematics of small, high speed turbomachinery components.

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