Simulation by Means Computational Fluids Dynamics of the Mixing Process Air-Natural Gas in a Turbocharger Diesel Engine

2010 ◽  
Author(s):  
Fabio A. Bermejo ◽  
Lesme A. Corredor
Keyword(s):  
Natural Gas ◽  
Public Transportation ◽  
Liquid Fuel ◽  
Intake Manifold ◽  
Mixing Process ◽  
Engine Operation ◽  
Operational Conditions ◽  
Computational Fluids Dynamics ◽  
Computational Fluids ◽  
Diesel Buses

Diesel buses of public transportation in the main cities of Colombia are formed by turbocharger engines, such machines could operate in dual Diesel-NG way using the gaseous fuel as main energy source and the liquid fuel to pilot ignition of the air-NG mixture previously formed. This research is centered on the studies about formation process of the mixture in the intake system in a turbocharger dual engine. In this study the transport equations are established, it is associated to the fluids which enter to the intake engine during a period of engine operation. This model is simulated by means of CFD tools, using an electronic injector to provide natural gas. Also it is considered the fluidynamic behavior of mixture. Finally an experimental design applied to the simulations is made with the goal of optimize operational conditions of the injector that allow to get the most homogeneous mixture on the inlet runner to one of the cylinders engine. This mixture was obtained injecting natural gas at a pressure of 10 bars and placing the injector as close to the intake manifold.

Experimental Investigation of a Heavy-Duty CI Engine Retrofitted to Natural Gas SI Operation

2018 ◽  
Author(s):  
Jinlong Liu ◽  
Hemanth Bommisetty ◽  
Cosmin E. Dumitrescu
Keyword(s):  
Natural Gas ◽  
Operating Conditions ◽  
Intake Manifold ◽  
Heavy Duty ◽  
Lean Burn ◽  
Engine Operation ◽  
Cycle Variation ◽  
Spark Timing ◽  
Ci Engine ◽  
Ci Engines

Heavy-duty compression-ignition (CI) engines converted to natural gas (NG) operation can reduce the dependence on petroleum-based fuels and curtail greenhouse gas emissions. Such an engine was converted to premixed NG spark-ignition (SI) operation through the addition of a gas injector in the intake manifold and of a spark plug in place of the diesel injector. Engine performance and combustion characteristics were investigated at several lean-burn operating conditions that changed fuel composition, spark timing, equivalence ratio, and engine speed. While the engine operation was stable, the reentrant bowl-in-piston (a characteristic of a CI engine) influenced the combustion event such as producing a significant late-combustion, particularly for advanced spark timing. This was due to an important fraction of the fuel burning late in the squish region, which affected the end of combustion, the combustion duration, and the cycle-to-cycle variation. However, the lower cycle-to-cycle variation, stable combustion event, and the lack of knocking suggest a successful conversion of conventional diesel engines to NG SI operation using the approach described here.

Modeling and Simulation of an Underwater Remotely Operated Vehicle (ROV) for Surveillance and Inspection of Port Facilities Using CFD Tools

2008 ◽  
Author(s):  
Rau´l A. Valencia ◽  
Juan A. Rami´rez ◽  
Luis B. Gutie´rrez ◽  
Manuel J. Garci´a
Keyword(s):  
Visual Information ◽  
Computer Aided Design ◽  
3D Scanner ◽  
Remotely Operated Vehicle ◽  
Operational Conditions ◽  
Computational Fluids Dynamics ◽  
Port Facilities ◽  
Computational Fluids ◽  
Aided Design ◽  
Underwater Structures

This article presents theoretical and computational studies with Computational Fluids Dynamics (CFD) tools of an Underwater Remotely Operated Vehicle (ROV), required to obtain reliable visual information, used for surveillance and maintenance of ship shells and underwater structures of Colombian port facilities. The thrust force is analyzed at the operational conditions by using CFD tools (FLUENT™, CFX™, COSMOSFLOW™) and the information about forces, torques and power of the vehicle’s thrusters is obtained. The commercial propellers were modeled by using a reverse engineering process with a 3D scanner and Computer Aided Design (CAD) software (RAPIDFORM™). The results obtained with the CFD package allowed to evaluate several operating scenarios of the vehicle that are used for feedback purposes in the design process of the ROV before it be manufactured.

Performance and heat release analysis of a pilot-ignited natural gas engine

2002 ◽  
Vol 3 (3) ◽  
pp. 171-184 ◽  
Author(s):  
S. R. Krishnan ◽  
M Biruduganti ◽  
Y Mo ◽  
S. R. Bell ◽  
K. C. Midkiff
Keyword(s):  
Natural Gas ◽  
Heat Release ◽  
Specific Energy Consumption ◽  
Intake Manifold ◽  
Dual Fuel ◽  
Injection Timing ◽  
Compression Ignition Engine ◽  
Engine Operation ◽  
Operating Variables ◽  
Release Analysis

The influence of engine operating variables on the performance, emissions and heat release in a compression ignition engine operating in normal diesel and dual-fuel modes (with natural gas fuelling) was investigated. Substantial reductions in NOx emissions were obtained with dual-fuel engine operation. There was a corresponding increase in unburned hydrocarbon emissions as the substitution of natural gas was increased. Brake specific energy consumption decreased with natural gas substitution at high loads but increased at low loads. Experimental results at fixed pilot injection timing have also established the importance of intake manifold pressure and temperature in improving dual-fuel performance and emissions at part load.

Burner Development for Flexible Engine Operation of the Newest Siemens Gas Turbines

2003 ◽  
Author(s):  
Bernd Prade ◽  
Ju¨rgen Meisl ◽  
Peter Berenbrink ◽  
Holger Streb ◽  
Stefan Hoffmann
Keyword(s):  
Natural Gas ◽  
Gas Turbines ◽  
Liquid Fuel ◽  
Fuel Quality ◽  
Nox Emissions ◽  
Combustion System ◽  
Engine Operation ◽  
Water Emulsion ◽  
Combustion Dynamics ◽  
Wide Range

The newest Siemens gas turbine family has already been well received by the market. Nevertheless, the market drives continuing development of the family and the combustion system. Central focus is put on further increasing reliability and component lifetime and on increased inspection cycles, as well as increasing the engine power output and efficiency, which is directly linked to higher turbine inlet temperatures. Increasing attention, however, is given to the flexibility concerning fuel quality and according fluctuations. Additionally, more and more strict emission requirements must be considered. This paper especially reports on demonstration of the capability of the Siemens gas turbines with an annular combustion system to fulfil the requirements for the highest operational flexibility. Thus, the combustion system has been tested and qualified for the highest operating flexibility with special fuel requirements such as burning Naphtha, Light Oil #2 and Natural gas with an extremely wide range of heating values as well. Also special operation modes such as fuel changeover, fastest load changes for island grid operation, frequency response and load rejection require this highly flexible combustion system without any hardware exchange. In different frames when fired with natural gas, base load is reached with the NOx emissions ranging well below 25 ppmvd, confirming the high potential of this advanced hybrid burner. In liquid fuel operation, dry NOx emissions of 75ppmvd were demonstrated but by injecting fuel / water emulsion NOx emissions were reduced to below 42 ppmvd with different liquid fuel qualities. Combustion dynamics, unburned Hydrocarbons, CO and soot emissions remained always below the required limits.

Enhancing Fuel Flexibility in Solar’s® Titan™ 250 Dry Low Emissions Combustion System

2021 ◽  
Author(s):  
Michael Ramotowski ◽  
Donald Cramb
Keyword(s):  
Natural Gas ◽  
Gas Turbines ◽  
Liquid Fuel ◽  
Combustion Stability ◽  
Liquid Fuels ◽  
Dual Fuel ◽  
Combustion System ◽  
Engine Operation ◽  
Combustion Systems ◽  
Electrical Generation

Abstract Industrial gas turbines serve in a variety of markets involving wide ranging duty cycles, fuel types and quality and emission requirements. For the Oil & Gas markets, applications range from mechanical drive, compressor sets and electrical generation that may be located in developed, remote or off-shore areas requiring a backup fuel (usually a liquid fuel). Upstream applications often require the gas turbine to burn a wide Wobbe range of fuels with varying gas compositions. For Power Generation applications, flexibility in operating range and low emissions are usually required. This paper describes Solar’s latest SoLoNOx™ (DLE) combustion system developments for the Titan 250 for both gaseous and liquid fuels with a focus on fuel type and quality, operability and emissions from both rig and engine tests. Several combustion systems will be discussed including gas only, dual fuel and a dual fuel Lean Direct Injection (LDI) system for burning lower quality liquid fuels. Engine tests were performed with blends of reactive gases (propane and butane), inert gas (carbon dioxide) and natural gas covering a wide Wobbe range from 30 to 60 WI (MJ/Nm3). Full engine qualification testing was performed which included operability, emissions and combustion stability for both the gas only and LDI combustion systems. The LDI system is based on the dry low emissions combustion system used for gas operation and thus offers low NOx emissions on gaseous fuels with the ability to burn lower quality liquid fuels for backup operation. A dual fuel lean premixed combustion system was also fully engine qualified for natural gas and liquid fuel. High pressure single injector rig tests using hydrogen blends with pipeline quality natural gas were also performed to qualify these fuels for engine operation in the dry low emission combustion systems with up to 30% hydrogen. The primary focus of testing was to determine overall operability, turndown, flashback risk and emissions.

Analysis of the Air-Fuel Mixture Control in Natural Gas Fuelled Turbocharged Engines

2008 ◽  
Author(s):  
Francisco Payri ◽  
Jose Galindo ◽  
Jose Manuel Luja´n ◽  
He´ctor Climent
Keyword(s):  
Natural Gas ◽  
Public Transportation ◽  
Dynamic Properties ◽  
Fluid Dynamic ◽  
Fuel Mixture ◽  
Injection System ◽  
Intake Manifold ◽  
Injection Timing ◽  
Gas Dispersion ◽  
Point Injection

The use of natural gas in medium and heavy duty engines for public transportation is a promising way for reducing exhaust emissions. Computer simulations, coupled with engine tests, have arisen as a valuable methodology to study the gas exchange processes inside intake and exhaust manifolds. A wave action model is set up in order to simulate a natural gas fuelled turbocharged engine. Once the modeling results show good agreement when comparing with measured data at different running conditions in terms of fluid dynamic properties, the model is used to study the air-fuel mixture process in the intake manifold and optimize the injection system behavior. Comparisons of modeled air-fuel composition in the cylinders are performed with both single and multi-point injection strategies. These cylinder to cylinder air-fuel mixture dispersion problems are analyzed at both steady and transient engine running conditions. Steady operation is performed correctly when using single-point injection since the gas mixer upstream the throttle valve enhances the mixing process. However, significant gas dispersion among cylinders appears during an engine load transient. With multi-point injection the critical parameter is the injection timing, since it is usually larger than the intake stroke period and, if it is not conveniently arranged, significant natural gas dispersion among cylinders may appear at both steady and transient running conditions.

Finite Element Model to Predict the Bioconversion Rate of Glucose to Fructose using Escherichia coli K12 for Sugar Production from Date

2015 ◽  
Vol 11 (1) ◽  
pp. 105-113 ◽  
Author(s):  
Maher Trigui ◽  
Karim Gabsi ◽  
Walid Zneti ◽  
Suzelle Barrington ◽  
Ahmed Noureddine Helal
Keyword(s):  
Escherichia Coli ◽  
Induction Time ◽  
Volume Fraction ◽  
Element Model ◽  
Initial Concentration ◽  
Computational Fluids Dynamics ◽  
Date Syrup ◽  
Computational Fluids ◽  
Two Phases ◽  
Inoculum Volume

Abstract In this study, Bioconversion process of glucose to fructose from date syrup using Escherichia coli K12 is modeled using a commercial computational fluids dynamics (CFD) code fluent FLUENT 6.3.23 [8] which we implemented a user-defined functions (UDF) to simulate the interrelationships at play between various phases. A two phases CFD model was developed using an Eulerian – Eulerian approach to calculate the fructose volume fraction produced during time. The bioconversion process was studied as function of three initial concentration of glucose (0.14, 0.242 and 0.463gL–1), three induction time (60, 120 and 180 mn) and three inoculum volume (100, 120 and 150mL). The numerical results are compared with experimental data for bioconversion rate and show good agreement (R2= 0.894). The optimal condition of diffusion was obtained by applying an initial concentration of glucose less than 0.2gL–1 and induction time great than 100 minutes.

Experimental Investigation of a Heavy-Duty Compression-Ignition Engine Retrofitted to Natural Gas Spark-Ignition Operation

2019 ◽  
Vol 141 (11) ◽  
Author(s):  
Jinlong Liu ◽  
Hemanth Kumar Bommisetty ◽  
Cosmin Emil Dumitrescu
Keyword(s):  
Natural Gas ◽  
Spark Ignition ◽  
Operating Conditions ◽  
Compression Ignition ◽  
Heavy Duty ◽  
Compression Ignition Engine ◽  
Engine Operation ◽  
Cycle Variation ◽  
Spark Timing ◽  
Ci Engines

Heavy-duty compression-ignition (CI) engines converted to natural gas (NG) operation can reduce the dependence on petroleum-based fuels and curtail greenhouse gas emissions. Such an engine was converted to premixed NG spark-ignition (SI) operation through the addition of a gas injector in the intake manifold and of a spark plug in place of the diesel injector. Engine performance and combustion characteristics were investigated at several lean-burn operating conditions that changed fuel composition, spark timing, equivalence ratio, and engine speed. While the engine operation was stable, the reentrant bowl-in-piston (a characteristic of a CI engine) influenced the combustion event such as producing a significant late combustion, particularly for advanced spark timing. This was due to an important fraction of the fuel burning late in the squish region, which affected the end of combustion, the combustion duration, and the cycle-to-cycle variation. However, the lower cycle-to-cycle variation, stable combustion event, and the lack of knocking suggest a successful conversion of conventional diesel engines to NG SI operation using the approach described here.

Performance Prediction of Gas Turbine Under Different Strategies Using Low Heating Value Fuel

2013 ◽  
Author(s):  
Edson Batista da Silva ◽  
Marcelo Assato ◽  
Rosiane Cristina de Lima
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Equivalence Ratio ◽  
Safe Operation ◽  
Engine Operation ◽  
Heating Value ◽  
Gasification Process ◽  
Surge Margin ◽  
And Performance ◽  
Industrial Gas Turbine

Usually, the turbogenerators are designed to fire a specific fuel, depending on the project of these engines may be allowed the operation with other kinds of fuel compositions. However, it is necessary a careful evaluation of the operational behavior and performance of them due to conversion, for example, from natural gas to different low heating value fuels. Thus, this work describes strategies used to simulate the performance of a single shaft industrial gas turbine designed to operate with natural gas when firing low heating value fuel, such as biomass fuel from gasification process or blast furnace gas (BFG). Air bled from the compressor and variable compressor geometry have been used as key strategies by this paper. Off-design performance simulations at a variety of ambient temperature conditions are described. It was observed the necessity for recovering the surge margin; both techniques showed good solutions to achieve the same level of safe operation in relation to the original engine. Finally, a flammability limit analysis in terms of the equivalence ratio was done. This analysis has the objective of verifying if the combustor will operate using the low heating value fuel. For the most engine operation cases investigated, the values were inside from minimum and maximum equivalence ratio range.

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