scholarly journals Issues of emission evaluation of road-rail vehicles in the aspect of current type approval regulations

2019 ◽  
Vol 178 (3) ◽  
pp. 269-273
Author(s):  
Paweł DASZKIEWICZ ◽  
Łukasz RYMANIAK ◽  
Michalina KAMIŃSKA
Keyword(s):  
Environmental Performance ◽  
Test Bench ◽  
Exhaust Emissions ◽  
Operating Conditions ◽  
Engine Test Bench ◽  
Rail Vehicles ◽  
Type Approval ◽  
Wide Range ◽  
Negative Environmental Impact ◽  
The Impact

One of the ways to reduce exhaust emissions from vehicles is to replace worn-out shunting locomotives with road-rail tractors. The main purpose of this solution is to reduce the negative environmental impact of the vehicle and to reduce the fuel consumption compared to a shunting locomotive performing the same work. The tests on exhaust emissions of rail vehicles are carried out on an engine test bench, making it impossible to determine the environmental performance of these vehicles during real operation. Therefore, it is advisable to carry out measurements in real operating conditions in order to obtain reliable reference results. This enables the verification of vehicles ecological indicators in a wide range of operational work parameters. It is possible to obtain reliable results regarding the impact of the tested vehicle on the natural environment in this way and compare them with the applicable emission standards.

scholarly journals Ethanol/Gasoline Blends as Alternative Fuel in Last Generation Spark-Ignition Engines: A Review on CO and HC Engine Out Emissions

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4034
Author(s):  
Paolo Iodice ◽  
Massimo Cardone
Keyword(s):  
Physicochemical Properties ◽  
Alternative Fuels ◽  
Experimental Studies ◽  
Alternative Fuel ◽  
Exhaust Emissions ◽  
Spark Ignition ◽  
Operating Conditions ◽  
Spark Ignition Engine ◽  
Spark Ignition Engines ◽  
The Impact

Among the alternative fuels existing for spark-ignition engines, ethanol is considered worldwide as an important renewable fuel when mixed with pure gasoline because of its favorable physicochemical properties. An in-depth and updated investigation on the issue of CO and HC engine out emissions related to use of ethanol/gasoline fuels in spark-ignition engines is therefore necessary. Starting from our experimental studies on engine out emissions of a last generation spark-ignition engine fueled with ethanol/gasoline fuels, the aim of this new investigation is to offer a complete literature review on the present state of ethanol combustion in last generation spark-ignition engines under real working conditions to clarify the possible change in CO and HC emissions. In the first section of this paper, a comparison between physicochemical properties of ethanol and gasoline is examined to assess the practicability of using ethanol as an alternative fuel for spark-ignition engines and to investigate the effect on engine out emissions and combustion efficiency. In the next section, this article focuses on the impact of ethanol/gasoline fuels on CO and HC formation. Many studies related to combustion characteristics and exhaust emissions in spark-ignition engines fueled with ethanol/gasoline fuels are thus discussed in detail. Most of these experimental investigations conclude that the addition of ethanol with gasoline fuel mixtures can really decrease the CO and HC exhaust emissions of last generation spark-ignition engines in several operating conditions.

Experimental investigation of isothermal and reacting flow characteristics downstream of axisymmetric bluff body stabilizers under stratified or fully premixed inlet mixture conditions

2020 ◽  
Author(s):  
Γεώργιος Πατεράκης
Keyword(s):  
Experimental Investigation ◽  
Turbulent Flow ◽  
Bluff Body ◽  
Operating Conditions ◽  
Reacting Flow ◽  
Wide Range ◽  
Flow Features ◽  
Air Mixing ◽  
The Impact ◽  
Stratified Flames

The current work describes an experimental investigation of isothermal and turbulent reacting flow field characteristics downstream of axisymmetric bluff body stabilizers under a variety of inlet mixture conditions. Fully premixed and stratified flames established downstream of this double cavity premixer/burner configuration were measured and assessed under lean and ultra-lean operating conditions. The aim of this thesis was to further comprehend the impact of stratifying the inlet fuelair mixture on the reacting wake characteristics for a range of practical stabilizers under a variety of inlet fuel-air settings. In the first part of this thesis, the isothermal mean and turbulent flow features downstream of a variety of axisymmetric baffles was initially examined. The effect of different shapes, (cone or disk), blockage ratios, (0.23 and 0.48), and rim thicknesses of these baffles was assessed. The variations of the recirculation zones, back flow velocity magnitude, annular jet ejection angles, wake development, entrainment efficiency, as well as several turbulent flow features were obtained, evaluated and appraised. Next, a comparative examination of the counterpart turbulent cold fuel-air mixing performance and characteristics of stratified against fully-premixed operation was performed for a wide range of baffle geometries and inlet mixture conditions. Scalar mixing and entrainment properties were investigated at the exit plane, at the bluff body annular shear layer, at the reattachment region and along the developing wake were investigated. These isothermal studies provided the necessary background information for clarifying the combustion properties and interpreting the trends in the counterpart turbulent reacting fields. Subsequently, for selected bluff bodies, flame structures and behavior for operation with a variety of reacting conditions were demonstrated. The effect of inlet fuel-air mixture settings, fuel type and bluff body geometry on wake development, flame shape, anchoring and structure, temperatures and combustion efficiencies, over lean and close to blow-off conditions, was presented and analyzed. For the obtained measurements infrared radiation, particle image velocimetry, laser doppler velocimetry, chemiluminescence imaging set-ups, together with Fouriertransform infrared spectroscopy, thermocouples and global emission analyzer instrumentation was employed. This helped to delineate a number of factors that affectcold flow fuel-air mixing, flame anchoring topologies, wake structure development and overall burner performance. The presented data will also significantly assist the validation of computational methodologies for combusting flows and the development of turbulence-chemistry interaction models.

Uncertainty Analysis of Inflow Conditions on an HPT Gas Turbine Nozzle: Effect on Particle Deposition

2020 ◽  
Author(s):  
R. Friso ◽  
N. Casari ◽  
M. Pinelli ◽  
A. Suman ◽  
F. Montomoli
Keyword(s):  
Gas Turbine ◽  
Energy Efficient ◽  
Gas Turbines ◽  
Particle Deposition ◽  
Operating Conditions ◽  
Wide Range ◽  
And Performance ◽  
Gas Turbine Nozzle ◽  
The Impact ◽  
Inflow Conditions

Abstract Gas turbines (GT) are often forced to operate in harsh environmental conditions. Therefore, the presence of particles in their flow-path is expected. With this regard, deposition is a problem that severely affects gas turbine operation. Components’ lifetime and performance can dramatically vary as a consequence of this phenomenon. Unfortunately, the operating conditions of the machine can vary in a wide range, and they cannot be treated as deterministic. Their stochastic variations greatly affect the forecasting of life and performance of the components. In this work, the main parameters considered affected by the uncertainty are the circumferential hot core location and the turbulence level at the inlet of the domain. A stochastic analysis is used to predict the degradation of a high-pressure-turbine (HPT) nozzle due to particulate ingestion. The GT’s component analyzed as a reference is the HPT nozzle of the Energy-Efficient Engine (E3). The uncertainty quantification technique used is the probabilistic collocation method (PCM). This work shows the impact of the operating conditions uncertainties on the performance and lifetime reduction due to deposition. Sobol indices are used to identify the most important parameter and its contribution to life. The present analysis enables to build confidence intervals on the deposit profile and on the residual creep-life of the vane.

Thermal–Hydraulic Performance Analysis of a Convergent Double Pipe Heat Exchanger

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Ahmed T. Al-Sammarraie ◽  
Kambiz Vafai
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Hydraulic Performance ◽  
Operating Conditions ◽  
Contraction Ratio ◽  
Wide Range ◽  
Prandtl Numbers ◽  
Double Pipe ◽  
The Impact ◽  
Pipe Heat

The present investigation proposes an innovative convergent double pipe heat exchanger (C-DPHE). A two-dimensional (2D) axisymmetric heat transfer model with counterflow is employed to analyze the thermal and hydraulic performance of this configuration numerically. The impact of convergence in the flow direction, using a wide range of contraction ratio (Cr), is explored. The effect of Reynolds and Prandtl numbers on the flow and heat transfer is addressed, as well. The model results were validated with available data from the literature, and an excellent agreement has been confirmed. In general, the findings of the present study indicate that increasing the contraction ratio increases heat transfer and pressure drop in the C-DPHE. Moreover, this configuration has a prominent and sustainable performance, compared to a conventional double pipe heat exchanger (DPHE), with an enhancement in heat transfer rate up to 32% and performance factor (PF) higher than one. Another appealing merit for the C-DPHE is that it is quite effective and functional at low Reynolds and high Prandtl numbers, respectively, since no high-operating pumping power is required. Further, the optimal operating conditions can be established utilizing the comprehensive information provided in this work.

Design relations for predicting surface-ice clearing capacity of open channels

2000 ◽  
Vol 27 (6) ◽  
pp. 1230-1239 ◽  
Author(s):  
I Morin ◽  
R D Townsend ◽  
B Morse
Keyword(s):  
Environmental Parameters ◽  
Operating Conditions ◽  
Water Current ◽  
Ambient Conditions ◽  
Navigation Channel ◽  
Wide Range ◽  
Ice Concentration ◽  
Wind Characteristics ◽  
Surface Ice ◽  
The Impact

Numerical simulations are performed to evaluate the impact of various hydraulic and environmental parameters on the ice clearing capacity of a Lac St-Pierre navigation channel. The Lagrangian particle-dynamics (Pdyn) model is used to simulate a wide range of "operating" conditions that are representative of conditions observed on Lac St-Pierre. Simple relationships are developed that express both ice velocity and flux as functions of the geometry of the channel (width and plan-form shape) and ambient conditions (ice concentration, thickness, water current, wind magnitude and direction). These relationships reflect the importance of wind characteristics and areal ice concentration in regard to predicting both surface ice velocities and flux.Key words: ice clearing, channel geometry, ambient conditions.

On Compressor Station Layout

2003 ◽  
Author(s):  
Rainer Kurz ◽  
Sebouh Ohanian ◽  
Matt Lubomirsky
Keyword(s):  
Gas Turbine ◽  
Electric Motor ◽  
Operating Conditions ◽  
Performance Characteristics ◽  
General Context ◽  
Operational Flexibility ◽  
Gas Engine ◽  
Wide Range ◽  
The Individual ◽  
The Impact

This paper discusses issues that influence the decision on the arrangement of compressors and the type of equipment in gas pipeline compressor stations. Different concepts such as multiple small units versus single large units are considered, both regarding their impact on the individual station and the overall pipeline. The necessity of standby units is discussed. Various concepts for drivers (gas turbine, gas motor and electric motor) and compressors (centrifugal and reciprocating) are analyzed. The importance of considering all possible operating conditions is stressed. With the wide range of possible operating conditions for the pipeline in mind, the discussion will be brought into the general context of operational flexibility, availability, reliability, installation issues, remote control, and operability of gas turbine driven centrifugal compressors compared to other solutions such as electric motor driven compressors or gas engine driven reciprocating compressors. The impact of different concepts on emissions and fuel cost is discussed. Among the assumptions in this paper are the performance characteristics of the compressor. It will be outlined how these performance characteristics influence the conclusions.

The Impact of Micro-Surface Shaping on the Piston/Cylinder Interface of Swash Plate Type Machines

2015 ◽  
Author(s):  
Ashley M. Wondergem ◽  
Monika Ivantysynova
Keyword(s):  
Surface Profile ◽  
Sine Wave ◽  
Operating Conditions ◽  
Surface Shape ◽  
Hydrodynamic Bearing ◽  
Piston Cylinder ◽  
Wide Range ◽  
Surface Shaping ◽  
Pumping Mode ◽  
The Impact

With the wide use of axial piston machines of the swashplate type in industry, it is essential to maximize the overall efficiency of the machines. Focusing on the piston-cylinder interface, as it performs as a hydrodynamic bearing simultaneously fulfilling a sealing function, the overall machine can be improved by reducing the power losses due to viscous friction and leakage flow of this interface. This paper presents a research study in regards to altering the geometry of the piston through micro-surface shaping influencing the generation of the fluid film between the piston and the cylinder. This investigation utilizes a novel fully coupled fluid structure interaction model considering both thermal and elastic deformations of the solid bodies to predict the phenomena occurring within the fluid gap. Encompassed in this simulation study is a diversity of piston micro-surface shapes and a wide range of machine operating conditions. The designs presented include an axial sine wave, a flat, cylindrical design with tapered ends, a barreled shape, a combination of the axial sine wave and barrel, along with a circumferential sine wave. High pressure operating conditions in pumping mode as well as common operating conditions in both pumping and motoring mode are considered for the various designs. The results demonstrate up to a 30% reduction in energy dissipation from a standard piston-cylinder interface at higher pressure operating conditions (over 15% reduction considering all three interfaces of the machine) with the addition of a barrel surface shape while a 25% reduction (over 5% overall) is achievable at lower operating pressures in pumping mode with a waved barrel surface profile. As for motoring mode a 30% reduction (around 10% overall) is possible with the introduction of a waved barrel surface profile on the piston. It will also be shown, that not only are these reductions possible though microsurface shaping of the piston, but the reliability of the machine is also improved by reducing run-in wear all while maintaining a cost-effective, manufacturable design.

The Impact of the Surface Shape of the Piston on Power Losses

2014 ◽  
Author(s):  
Ashley M. Wondergem ◽  
Monika Ivantysynova
Keyword(s):  
Energy Dissipation ◽  
Cost Effective ◽  
Operating Conditions ◽  
Surface Shape ◽  
Critical Gap ◽  
Piston Cylinder ◽  
Wide Range ◽  
Load Carrying ◽  
Gap Height ◽  
The Impact

Axial piston machines are widely used in industry thus new cost-effective and highly efficient designs are needed. One way to increase efficiency and decrease cost is by altering the geometry along with the configuration of the piston/cylinder interface influencing the fluid film generation and in turn the energy dissipation and load carrying capacity while still having a design that is cost effective and easy to manufacture. This paper presents a study on a reduction of energy dissipation between the piston and cylinder over a wide range of operating conditions at both full and partial displacements based on the surface shape of the piston along with the minimum clearance. First, it is necessary to measure a base design and then compare those results to simulations in order to verify the simulation results. Once a baseline is established, various piston surface shapes and minimum clearances are then also simulated and compared back to the simulated baseline. Not only is energy dissipation important to compare, but also the minimum gap height over one revolution. The minimum gap height is in direct correlation to friction loss and wear. Therefore, this paper also includes an understanding of how the gap height affects the total losses thus leading to the importance of finding a relative clearance that satisfies a median between torque losses and leakage along with the importance of reducing the occurrence of critical gap heights to reduce the need for wear in in the machine.

Formaldehyde Formation in Large Bore Engines Part 2: Factors Affecting Measured CH2O

1999 ◽  
Vol 122 (4) ◽  
pp. 611-616 ◽  
Author(s):  
Daniel B. Olsen ◽  
Charles E. Mitchell
Keyword(s):  
Natural Gas ◽  
Air Pollutant ◽  
Operating Conditions ◽  
Factors Affecting ◽  
Natural Gas Engines ◽  
Spark Timing ◽  
Wide Range ◽  
Hazardous Air Pollutant ◽  
Relationship Of ◽  
The Impact

Current research shows that the only hazardous air pollutant of significance emitted from large bore natural gas engines is formaldehyde CH2O. A literature review on formaldehyde formation is presented focusing on the interpretation of published test data and its applicability to large bore natural gas engines. The relationship of formaldehyde emissions to that of other pollutants is described. Formaldehyde is seen to have a strong correlation to total hydrocarbon (THC) level in the exhaust. It is observed that the ratio of formaldehyde to THC concentration is roughly 1.0–2.5 percent for a very wide range of large bore engines and operating conditions. The impact of engine operating parameters, load, rpm, spark timing, and equivalence ratio, on formaldehyde emissions is also evaluated. [S0742-4795(00)01004-8]

Rayleigh-Taylor instability in oscillating liquid pistons

2018 ◽  
Vol 233 (4) ◽  
pp. 1236-1245 ◽  
Author(s):  
Samuel Langdon-Arms ◽  
Michael Gschwendtner ◽  
Martin Neumaier
Keyword(s):  
Taylor Instability ◽  
Operating Conditions ◽  
Surface Stability ◽  
Wide Range ◽  
Experimental Apparatus ◽  
In Series ◽  
Rayleigh Taylor Instability ◽  
Gas Expansion ◽  
Liquid Piston ◽  
The Impact

In this study, an experimental apparatus is used to excite four U-tube-shaped liquid pistons connected in series, and to study their behaviour. Some of the gas spaces are heated to induce piston oscillations; in others, gas expansion is utilised to produce a refrigeration effect. It was discovered that the liquid piston surface would become unstable and turbulent at relatively low gas charge pressures (2 bar–3 bar). Cylindrical polyethylene floats were employed at each piston surface in order to reduce the area of the free surface of each piston and allow experiments to be conducted over a wide range of operating conditions. Experiments were carried out using gas charge pressures in the range of 1 bar–6 bar. The resulting liquid piston oscillations were measured and analysed to assess the impact of any developing piston instability. Evidence of a liquid piston acceleration limit, likely resulting from the Rayleigh-Taylor instability phenomenon, is consistently observed during the experiments. The use of submerged polyethylene piston floats is found to increase the surface stability and enable maximum accelerations of 25 ms−2 to 30 ms−2.

Sign in / Sign up

Export Citation Format

Share Document