CFD Aerodynamic and Reactive Study of an Innovative Lean Combustion System in the Frame of the NEWAC Project

2010 ◽  
Author(s):  
Alessandro Marini ◽  
Lorenzo Bucchieri ◽  
Antonio Peschiulli
Keyword(s):  
Numerical Procedure ◽  
Research Programme ◽  
Injection System ◽  
Combustion System ◽  
Lean Burn ◽  
The Core ◽  
Numerical Tests ◽  
Lean Combustion ◽  
Annular Combustor ◽  
The Eu

This paper deals with the very last activities carried out by EnginSoft in the frame of the EU funded research programme NEWAC. The work regards the pre-production numerical tests performed on the single annular combustor with the purpose of verify its performance in reactive frame. The core of this study is the innovative lean-burn injection system technology, developed by University of Karlsruhe and AVIO for medium OPR. Such device has been widely investigated in previous activities in order to optimise the combustor layout and the numerical procedure for this work [1].

The Research of Lean Combustion Characteristic of Compound Injection System of Direct Injection Engine

2014 ◽  
Vol 532 ◽  
pp. 362-366 ◽  
Author(s):  
Jiang Feng Mou ◽  
Rui Qing Chen ◽  
Yi Wei Lu
Keyword(s):  
Gasoline Engine ◽  
Direct Injection ◽  
Injection System ◽  
Intake Manifold ◽  
Combustion Characteristic ◽  
Injection Timing ◽  
Mixed Gas ◽  
Lean Burn ◽  
Direct Injection Engine ◽  
Lean Combustion

This paper studies the lean burn limit characteristic of the compound injection system of the direct-injection gasoline engine. The low pressure nozzle on the intake manifold can achieve quality homogeneous lean mixture, and the direct injection in the cylinder can realized the dense mixture gas near the spark plug. By adjusting the two injection timing and injection quantity, and a strong intake tumble flow with special shaped combustion chamber, it can produces the reverse tumble to form different hierarchical levels of mixed gas in the cylinder. Experimental results show: the compound combustion system to the original direct-injection engine lean burn limit raise 1.8-2.5 AFR unit.

Thermoacoustic Analysis of a Full Annular Lean Burn Aero-Engine Combustor

2013 ◽  
Author(s):  
Antonio Andreini ◽  
Bruno Facchini ◽  
Andrea Giusti ◽  
Ignazio Vitale ◽  
Fabio Turrini
Keyword(s):  
Heat Release ◽  
Gas Turbines ◽  
Three Dimensional ◽  
Thermal Fluctuations ◽  
Injection System ◽  
Combustion Instabilities ◽  
Lean Burn ◽  
Acoustic Effect ◽  
Lean Combustion ◽  
Critical Issues

In order to reduce NOx emissions, modern gas turbines are often equipped with lean burn combustion systems, where the engine operates near the lean blow-out limits. One of the most critical issues of lean combustion technology is the onset of combustion instabilities related to a coupling between pressure oscillations and thermal fluctuations excited by the unsteady heat release. In this work a thermoacoustic analysis of a full annular combustor developed by AVIO is discussed. The system is equipped with an advanced PERM (Partially Evaporating and Rapid Mixing) injection system based on a piloted lean burn spray flame generated by a pre-filming atomizer. Combustor walls are based on multi-perforated liners to control metal temperature: these devices are also recognized as very effective sound absorbers, thus in innovative lean combustors they could represent a good means both for wall cooling and damping combustion instabilities. The performed analysis is based on the resolution of the eigenvalue problem related to an inhomogeneous wave equation which includes a source term representing heat release fluctuations (the so called Flame Transfer Function, FTF) in the flame region using a three-dimensional FEM code. A model representing the entire combustor was assembled including all the acoustically relevant geometrical features. In particular, the acoustic effect of multi-perforated liners was introduced by modeling the corresponding surfaces with an equivalent internal impedance. Different simulations with and without the presence of the flame were performed analyzing the influence of the multi-perforated liners. Furthermore, different modeling approaches for the FTF were examined and compared with each other. Comparisons with available experimental data showed a good agreement in terms of resonant frequencies in the case of passive simulations. On the other hand, when the presence of the flame is considered, comparisons with experiments showed the inadequacy of FTFs commonly used for premixed combustion and thus the necessity of an improved FTF, more suitable for liquid fueled gas turbines where the evaporation process could play an important role in the flame heat release fluctuations.

Experimental and Computational Results of Distributed Combustion for Application in Current Gas Turbine Engine Combustor Architectures

2011 ◽  
Author(s):  
Nick Overman ◽  
Jason Ryon
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Swirling Flow ◽  
Numerical Test ◽  
Injection System ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Lean Burn ◽  
Lean Combustion ◽  
Improved Performance

Current development and testing has lead to a fuel/air injection system for application in gas turbine engines that produces ultra low emissions and stable, lean combustion. The system is designed to operate with current combustor architectures similar to existing gas turbine engines. This paper presents both experimental and numerical test results demonstrating the benefits of such technology including extremely low emissions of NOx, CO, and un-burned hydrocarbons (UHC). Primary focus is on experimental results demonstrating reaction distribution and emissions. Numerical confirmation of flow field dynamics was used to develop an understanding of the re-circulation rates within the combustor and impact on reaction behavior. Several design configurations were tested to investigate the effects of aerodynamic stagnation point and fuel placement with respect to the aerodynamic shear layer produced by the swirling flow field. Test conditions were varied, including inlet air temperature and injector pressure drop for monitoring effects on the operating envelope of distributed reaction and on lean blow out limit. Results demonstrate the improved performance of a system capable of operating in a flameless or distributed reaction mode over that of a typical lean burn system.

The Discourses on Post-National Governance and the Democratic Deicit Absent an EU Government

2013 ◽  
Vol 9 (2) ◽  
pp. 177-188 ◽  
Author(s):  
Cesare Pinelli
Keyword(s):  
Time Frame ◽  
Representative Democracy ◽  
Political Life ◽  
Political Accountability ◽  
Joint Decision ◽  
The Core ◽  
Commission President ◽  
The Eu

The enduring joint decision trap in the absence of European government – Postnational constitutionalism – The dismissal of politics – Accountability of government before parliament at the core of representative democracy – Internalising the benefits and of externalising the disadvantages of staying together in the Union possible as long as political accountability is not ensured in the EU system – Breathing political life into the EU through constitutional practice without formal Treaty amendment – A time-frame for approval of treaty amendments – EP and the election of Commission president

scholarly journals Prechamber optimal selection for a two stage turbulent jet ignition type combustion system in CNG-fuelled engine

2019 ◽  
Vol 176 (1) ◽  
pp. 16-26 ◽  
Author(s):  
Ireneusz PIELECHA ◽  
Wojciech BUESCHKE ◽  
Maciej SKOWRON ◽  
Łukasz FIEDKIEWICZ ◽  
Filip SZWAJCA ◽  
...  
Keyword(s):  
High Speed ◽  
Internal Combustion Engines ◽  
Combustion Process ◽  
Optimization Methods ◽  
Turbulent Jet ◽  
Experimental Investigations ◽  
Combustion System ◽  
Two Stage ◽  
Lean Burn ◽  
High Speed Engine

Searching for further reduction of fuel consumption simultaneously with the reduction of toxic compounds emission new systems for lean-mixture combustion for SI engines are being discussed by many manufacturers. Within the European GasOn-Project (Gas Only Internal Combustion Engines) the two-stage combustion and Turbulent Jet Ignition concept for CNG-fuelled high speed engine has been proposed and thoroughly investigated where the reduction of gas consumption and increasing of engine efficiency together with the reduction of emission, especially CO2 was expected. In the investigated cases the lean-burn combustion process was conducted with selection of the most effective pre-combustion chamber. The experimental investigations have been performed on single-cylinder AVL5804 research engine, which has been modified to SI and CNG fuelling. For the analysis of the thermodynamic, operational and emission indexes very advanced equipment has been applied. Based on the measuring results achieved for different pre-chamber config-urations the extended methodology of polioptimization by pre-chamber selection and the shape of main chamber in the piston crown for proposed combustion system has been described and discussed. The results of the three versions of the optimization methods have been comparatively summarized in conclusions.

scholarly journals Demographic and functional potential of the Novosibirsk urban region in Russian Federation. A case study of transformations using the directional profile method

2016 ◽  
Vol 2 (320) ◽  
Author(s):  
Paulina Tobiasz-Lis ◽  
Marcin Wójcik
Keyword(s):  
Russian Federation ◽  
Research Programme ◽  
Economic Transformation ◽  
Urban Region ◽  
Railway Line ◽  
The Core ◽  
Functional Development ◽  
National Settlement ◽  
National Settlement System

The research presented in this article focuses on the urban region of Novosibirsk, which is one of the most industrialized part of Siberia and the Asian part of Russian Federation. To show relationships between the city as the core of the region and its peripheral area a case study analysing territorial units within the southern settlement belt along the Novosibirsk–Cherepanovo regional railway line over a distance of approx. 100 km. This belt was chosen because of the continuity of the settlement and due to the presence of different functional types of edge towns. The adopted system, from the core to the area of weakening direct links to Novosibirsk, helped to define the directional profile of the urban region as relating to the demographic and economic characteristics. The research was based on two methods of determining the functions of cities in the national settlement system: a research programme concerning the genesis of functional development and a research programme of specialised functions, the purpose of which is to determine the economic base (exogenous functions) of territorial units. The presented results have shown general tendencies in the transformations of the Novosibirsk urban region’s spatial structure, both in long-term perspective (the generic view of function development) and under contemporary circumstances related to the economic transformation of Russia.

Adiabatic Effectiveness and Flow Field Measurements in a Realistic Effusion Cooled Lean Burn Combustor

2015 ◽  
Vol 138 (3) ◽  
Author(s):  
Antonio Andreini ◽  
Riccardo Becchi ◽  
Bruno Facchini ◽  
Lorenzo Mazzei ◽  
Alessio Picchi ◽  
...  
Keyword(s):  
Flow Field ◽  
Field Measurements ◽  
Injection System ◽  
Wall Region ◽  
Test Model ◽  
Nox Emissions ◽  
Lean Burn ◽  
Experimental Apparatus ◽  
Adiabatic Effectiveness ◽  
The Impact

Over the last ten years, there have been significant technological advances toward the reduction of NOx emissions from civil aircraft engines, strongly aimed at meeting stricter and stricter legislation requirements. Nowadays, the most prominent way to meet the target of reducing NOx emissions in modern combustors is represented by lean burn swirl stabilized technology. The high amount of air admitted through a lean burn injection system is characterized by very complex flow structures such as recirculations, vortex breakdown, and precessing vortex core (PVC) that may deeply interact in the near wall region of the combustor liner. This interaction makes challenging the estimation of film cooling distribution, commonly generated by slot and effusion systems. The main purpose of the present work is the characterization of the flow field and the adiabatic effectiveness due to the interaction of swirling flow, generated by real geometry injectors, and a liner cooling scheme made up of a slot injection and an effusion array. The experimental apparatus has been developed within EU project LEMCOTEC (low emissions core-engine technologies) and consists of a nonreactive three-sectors planar rig; the test model is characterized by a complete cooling system and three swirlers, replicating the geometry of a GE Avio PERM (partially evaporated and rapid mixing) injector technology. Flow field measurements have been performed by means of a standard 2D PIV (particle image velocimetry) technique, while adiabatic effectiveness maps have been obtained using PSP (pressure sensitive paint) technique. PIV results show the effect of coolant injection in the corner vortex region, while the PSP measurements highlight the impact of swirled flow on the liner film protection separating the contribution of slot and effusion flows. Furthermore, an additional analysis, exploiting experimental results in terms of heat transfer coefficient, has been performed to estimate the net heat flux reduction (NHFR) on the cooled test plate.

The EU Response to Criminal Misuse of Cryptocurrencies: The Young, already Outdated 5th Anti-Money Laundering Directive

2020 ◽  
Vol 28 (3) ◽  
pp. 217-251
Author(s):  
Valentina Covolo
Keyword(s):  
Money Laundering ◽  
Business Models ◽  
International Standards ◽  
Present Contribution ◽  
The Core ◽  
Cross Border ◽  
The Us ◽  
New Business ◽  
New Business Models ◽  
The Eu

Abstract Combatting criminal misuse of cryptocurrencies was at the core of the fatf agenda under the US Presidency, culminating in June 2019 with the thorough extension of international standards against money laundering over virtual assets’ markets. This echoed the first legislative measure regulating virtual currencies adopted by the EU a year before. Directive 2018/843, better known as the 5th Anti-Money Laundering Directive, fails however to address key technological breakthroughs and new business models, which continuously make the ever-growing and fast-paced crypto economy evolve. Against this background, the present contribution investigates shortfalls and challenges that lay ahead in the light of the new fatf Recommendations. It ultimately argues that the preventive anti-money laundering measures cannot dispense with the establishment of a cross-border integrated supervisory and enforcement system.

The EU's Internal Market and the Free Movement of Labor

2017 ◽  
pp. 61-75 ◽  
Author(s):  
Zeynep Kaplan
Keyword(s):  
Labor Markets ◽  
Market Integration ◽  
Labor Mobility ◽  
Core Element ◽  
Labor Market Integration ◽  
The Core ◽  
Free Mobility ◽  
Recent Trends ◽  
European Labor Markets ◽  
The Eu

Free mobility of labor has been the core element of the European integration process. The aim of this chapter is to analyze the effects and challenges of the labor mobility within the EU. The analysis then focuses on the recent trends in labor mobility. Cross-border labor mobility remains low in the EU. The main reasons behind the low levels of labor mobility in the EU include linguistic and cultural reasons, as well as non-tariff barriers such as pension rules, recognition of professional qualification or social security differences. Removal of impediments to free mobility of labor and improvement of flexibility of the European labor markets will strengthen the EU's labor market integration.

Interoperability Issues for Systems Managing Competency Information

2010 ◽  
pp. 83-105
Author(s):  
Bernard Blandin ◽  
Geoffrey Frank ◽  
Simone Laughton ◽  
Kenji Hirata
Keyword(s):  
Supply Chain ◽  
Final Section ◽  
Reference Model ◽  
Research Programme ◽  
Semantic Model ◽  
Research Directions ◽  
The Third ◽  
The Core ◽  
Digital Services ◽  
Core Part

This chapter has four sections. The first one describes how the needs for interoperability in exchanging competency information have been addressed so far. The second part adopts a “Digital Services Supply Chain” approach and discusses the issues related to the exchange of competency information across systems regarding this approach. The third part is the core part of this chapter. It describes the 4 levels of the proposed approach: the Conceptual Reference Model (CRM), the Semantic Model, the Information Model and the Data Model. The final section presents the research directions currently envisaged, and the research programme needed to make the proposed approach operational.

Sign in / Sign up

Export Citation Format

Share Document