Ignition Delay and Combustion Characteristics of Gaseous Fuel Jets

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Dung Ngoc Nguyen ◽  
Hiroaki Ishida ◽  
Masahiro Shioji
Keyword(s):  
Natural Gas ◽  
Ambient Temperature ◽  
Ignition Delay ◽  
Internal Combustion Engines ◽  
Ambient Pressure ◽  
Combustion Characteristics ◽  
Spontaneous Ignition ◽  
Ambient Conditions ◽  
Mixture Formation ◽  
Gaseous Fuels

Gaseous fuels, such as hydrogen and natural gas, are utilized in internal combustion engines for spark-ignition operation. To improve thermal efficiency and to ensure control at good heat-release rates, combustion systems with direct-injection and spontaneous-ignition operation may be preferable. The main objective of this research was to provide fundamental data for the ignition and combustion of hydrogen, natural gas, and methane. Experiments were conducted in a constant-volume combustion vessel to investigate the effects of ambient temperature on ignition delay and combustion characteristics for various injector and ambient conditions. Experimental results showed that all gaseous fuels exhibited similar ignition-delay trends: ignition delay (τ) increased as ambient temperature (Ti) decreased. Among these fuels, hydrogen jets exhibited much shorter τ than natural gas and methane jets at the same Ti and could be ignited at a lower temperature, Ti=780 K. A shorter ignition delay of hydrogen may be attained by controlling the mixture formation by lowering the injection pressure (pj), enlarging the nozzle-hole diameter (dN), increasing the ambient pressure (pi), and increasing the oxygen mole fraction (rO2). In contrast, the methane jet exhibited the longest τ over the whole range of Ti and suffered from misfiring at a higher Ti of 910 K. For natural gas, ignition delay was observed to be shorter than that for methane, owing to a small amount of butane with good ignitability. More specifically, the ignition delay of natural gas differed slightly when dN and pj varied but changed drastically when pi and rO2 decreased. Based on these data, the feasibility of gaseous fuels for compression-ignition engines is discussed from the viewpoint of mixture formation and chemical reaction.

Gas-to-Liquid Sprays at Different Injection and Ambient Conditions

2010 ◽  
Vol 133 (3) ◽  
Author(s):  
Dung Ngoc Nguyen ◽  
Hiroaki Ishida ◽  
Masahiro Shioji
Keyword(s):  
Oxygen Concentration ◽  
Ignition Delay ◽  
Alternative Fuels ◽  
Ambient Pressure ◽  
Cetane Number ◽  
Combustion Characteristics ◽  
Gas Oil ◽  
Ambient Conditions ◽  
Ignition Quality ◽  
Gas To Liquid

Alternative fuels exhibit potential as a clean fuel and suitable to address problems of energy security and environmental pollution. The main objective of this research was to provide the fundamental data of ignition delay and combustion characteristics for gas-to-liquid (GTL) fuels. Experiments were carried out in a constant-volume vessel under diesel-engine conditions to study the effects of various injection and ambient conditions on ignition and combustion characteristics. The results showed that all tested fuels exhibited similar ignition-delay trends: Ignition delay increased as ambient temperature, ambient pressure, and oxygen concentration decreased. The result of changing injection pressures and nozzle-hole diameters did not significantly affect ignition-delay values for all tested fuels. The variation in ignition-delay values was small at temperatures higher than 700 K but large at temperatures less than 700 K. In addition, the result showed that GTL fuels with high cetane number corresponded to shorter ignition delay and smoother heat-release rate than those for gas-oil (conventional diesel fuel) at the same temperature, pressure, and oxygen concentration. The blend GTL fuel improved ignition quality and combustion than that of gas-oil. Shadowgraph images showed that GTL fuels exhibited shorter spray penetration and mixed with the hot air quicker than gas-oil. In addition, GTL fuels showed suitability for premixed charge compression-ignition operations owing to ignitability at low temperature. The obtained results provide useful information for finding the optimal conditions for the design and control of diesel engines fuelled by synthetic GTL fuels.

Combustion characteristics of compressed natural gas/diesel dual-fuel turbocharged compressed ignition engine

2003 ◽  
Vol 217 (9) ◽  
pp. 833-838 ◽  
Author(s):  
Liu Shenghua ◽  
Zhou Longbao ◽  
Wang Ziyan ◽  
Ren Jiang
Keyword(s):  
Natural Gas ◽  
Ignition Delay ◽  
Combustion Characteristics ◽  
Operating Conditions ◽  
Dual Fuel ◽  
Compressed Natural Gas ◽  
Delay Effects ◽  
Low Load ◽  
Performance And Emissions ◽  
Ci Engine

The combustion characteristics of a turbocharged natural gas and diesel dual-fuelled compression ignition (CI) engine are investigated. With the measured cylinder pressures of the engine operated on pure diesel and dual fuel, the ignition delay, effects of pilot diesel and engine load on combustion characteristics are analysed. Emissions of HC, CO, NOx and smoke are measured and studied too. The results show that the quantity of pilot diesel has important effects on the performance and emissions of a dual-fuel engine at low-load operating conditions. Ignition delay varies with the concentration of natural gas. Smoke is much lower for the developed dual-fuel engine under all the operating conditions.

The Effect of Ambient Conditions on the Performance of Supplementary Fired Gas-Steam Combined Cycle

2006 ◽  
Author(s):  
M. J. Kermani ◽  
B. Rad Nasab ◽  
M. Saffar-Avval
Keyword(s):  
Power Plant ◽  
Ambient Temperature ◽  
Gas Turbine ◽  
Ambient Pressure ◽  
Combined Cycle ◽  
Ambient Conditions ◽  
Site Location ◽  
Steam Generators ◽  
Steam Cycle

The effect of ambient conditions, ambient temperature and site location of the power plant (the altitude or ambient pressure), on the performance of a typical supplementary fired (SF) gas-steam combined cycle (CC) is studied, and its performances are compared with that of the unfired case. The CC used in the present study is comprised of two V94.2 gas turbine units, two HR-steam generators and a single steam cycle. For the cases studied, it is observed that SF can increase the total net power of the CC by 5% and the efficiency for the fired-cycle is observed to be about 1% less than that of unfired-cycle case. The variations of the total net power with ambient temperature for both supplementary fired and unfired cases (slope w.r.t. the ambient temperature) are almost identical.

Experimental Study of NOx Formation in Lean, Premixed, Prevaporized Combustion of Fuel Oils at Elevated Pressures

2007 ◽  
Author(s):  
P. Gokulakrishnan ◽  
M. J. Ramotowski ◽  
G. Gaines ◽  
C. Fuller ◽  
R. Joklik ◽  
...  
Keyword(s):  
Natural Gas ◽  
Ignition Delay ◽  
Pilot Scale ◽  
Combustion Characteristics ◽  
Premixed Combustion ◽  
Fuel Oil ◽  
Liquid Fuels ◽  
Nox Formation ◽  
Lean Premixed Combustion ◽  
Lean Premixed

Dry low Emissions (DLE) systems employing lean, premixed combustion have been successfully used with natural gas in combustion turbines to meet stringent emissions standards. However, the burning of liquid fuels in DLE systems is still a challenging task due to the complexities of fuel vaporization and air premixing. Lean, Premixed, Prevaporized (LPP) combustion has always provided the promise of obtaining low pollutant emissions while burning liquid fuels such as kerosene and fuel oil. Because of the short ignition delay times of these fuels at elevated temperatures, the autoignition of vaporized higher hydrocarbons typical of most practical liquid fuels has proven difficult to overcome when burning in lean, premixed mode. To avoid this autoignition problem, developers of LPP combustion systems have focused mainly on designing premixers and combustors that permit rapid mixing and combustion of fuels before spontaneous ignition of the fuel can occur. However, none of the reported works in the literature has looked at altering fuel combustion characteristics in order to delay the onset of ignition in lean, premixed combustion systems. The work presented in this paper describes the development of a patented low-NOx LPP system for combustion of liquid fuels which modifies the fuel rather than the combustion hardware in order to achieve LPP combustion. In the initial phase of the development, laboratory-scale experiments were performed to study the combustion characteristics, such as ignition delay time and NOx formation, of the liquids fuels that were vaporized into gaseous form in the presence of nitrogen diluent. In phase two, an LPP combustion system was commissioned to perform pilot-scale tests on commercial turbine combustor hardware. These pilot-scale tests were conducted at typical compressor discharge temperatures and at both atmospheric and high pressures. In this study, vaporization of the liquid fuel in an inert environment has been shown to be a viable method for delaying autoignition and for generating a gaseous fuel stream with characteristics similar to natural gas. Tests conducted in both atmospheric and high pressure combustor rigs utilizing swirl-stabilized burners designed for natural gas demonstrated operation similar to that obtained when burning natural gas. Emissions levels were similar for both the LPP fuels (fuel oil #1 and #2) and natural gas, with any differences ascribed to the fuel-bound nitrogen present in the liquid fuels. Extended lean operation was observed for the liquid fuels as a result of the wider lean flammability range for these fuels compared with natural gas. Premature ignition of the LPP fuel was controlled by the level of inert gas in the vaporization process.

Application of Mechanisms for the Control of Autoignition in High Power Internal Combustion Engine Fueled With Natural Gas

2013 ◽  
Author(s):  
Jorge Duarte Forero ◽  
German Amador Diaz ◽  
Jesus Garcia Garcia ◽  
Marco San Juan Mejia ◽  
Lesme Corredor Martinez
Keyword(s):  
Natural Gas ◽  
Internal Combustion Engine ◽  
Control Strategy ◽  
Internal Combustion Engines ◽  
Feedforward Control ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Control Loop ◽  
Gaseous Fuels ◽  
Methane Number

In this paper, a thermodynamic model of a spark ignition internal combustion engine fueled with natural gas is developed in order to estimate the air-fuel-unburned gas temperature at before top dead center (BTDC). This temperature is used as controlled variable in a control loop in order to avoid the autoignition phenomena when the engine operates with a fuel with different methane number from the methane number requirement of the engine. The model formulation is based on a polytropic compression proccess whose coefficient was determined experimentally in a turbocharged internal combustion engine fueled with natural gas. To make feasible the use of differents gaseous fuels from natural gas, it was necessary to design two control strategies to avoid the knocking phenomenon and choose the best one. The ambient temperature is the disturbance considered, whose changes are significant in different places in the world. The first control strategy that was implemented is called “Robust”, which employs a conventional feedback control loop with a robust controller which is designed. The response of this control loop is compared to the response of the second control strategy called “Feedforward control”. The results obtained reveals that Feedforward control strategy has better performance than robust control strategy for this application. The control strategy and the model proposed will allow increase the range of application of gaseous fuels with low methane number (MN) leading to guarantee a safe running in internal combustion engines that currently are fueled with natural gas.

scholarly journals Ambient Temperature and Pressure Corrections for Aircraft Gas Turbine Idle Pollutant Emissions

1976 ◽  
Author(s):  
J. W. Marzeski ◽  
W. S. Blazowski
Keyword(s):  
Ambient Temperature ◽  
Ambient Pressure ◽  
Pressure Ratio ◽  
Operating Conditions ◽  
Pollutant Emissions ◽  
Pollutant Emission ◽  
Emission Model ◽  
Correction Factors ◽  
Ambient Conditions ◽  
Temperature And Pressure

Recent investigations have indicated that aircraft engine exhaust emissions are sensitive to ambient conditions. This paper reports on combustor rig testing intended to evaluate variations due to ambient temperature and pressure with special emphasis on idle engine operating conditions. Empirically determined CO, CxHy, and NOx correction factors — the ratio of the pollutant emission index value obtained during standard day operation to that resulting during actual ambient conditions — are presented. The effects of engine idle cycle pressure ratio, primary zone fuel-air ratio, and fuel type were investigated. Ambient temperature variations were seen to cause substantial emission changes; correction factors in excess of 2.0 were determined in some cases. Ambient pressure variations were found to be less substantial. A previously published NOx emission model and a simplified hydrocarbon combustion analysis are shown to be in general agreement with the empirical results.

Syngas Laminar Flame Speed Computation and its Application to Gaseous Fueled Spark Ignited Engines Performance Prediction

2016 ◽  
Author(s):  
Hui Xu ◽  
Leon A. LaPointe ◽  
Robin J. Bremmer
Keyword(s):  
Natural Gas ◽  
Chemical Kinetics ◽  
Laminar Flame ◽  
Combustion Process ◽  
Engine Performance ◽  
Ambient Conditions ◽  
Piston Engine ◽  
Natural Gas Engines ◽  
Gaseous Fuels ◽  
Engine Combustion

Gaseous fueled spark ignited (SI) engines are often developed using pipeline quality natural gas as the fuel. However, natural gas engines are occasionally expected by customers to accommodate different fuel compositions when deployed in the field. Depending on the source or production processing of the fuel and the ambient conditions, gaseous fuels can have different levels of heavy hydrocarbons and/or significant levels of diluents when compared to natural gas. In recent years, there are increasing interests in using synthesis gas (syngas) from renewable sources in gaseous fueled spark ignition engines. This work investigated syngas compositions from different production processes and describes a methodology to predict engine performance using syngas. Syngas composition variations can provide different laminar flame speeds (LFS), which can result in changes in combustion burn rate, heat release rate and knock likelihood, if the engine combustion process is not optimized appropriately. It is challenging to obtain LFS data at the high pressure and temperature conditions that are characteristic of the piston engine combustion process. It has proven to be effective to employ a chemical kinetics solver using an appropriate chemical kinetics mechanism to obtain LFS values under piston engine combustion conditions. Alternative chemical kinetics mechanisms were investigated to identify one which best characterized combustion performance relative to detailed rig and engine measurements. With this appropriate chemical kinetics mechanism, LFS results are now used to guide natural gas engine combustion tuning when using syngas as a fuel. Engine performance is predicted in terms of NOx emissions and knock likelihood using the in-house developed methodology.

Investigation of the Effect of Plume Number on Spray Collapse

2019 ◽  
Author(s):  
Panos Sphicas
Keyword(s):  
Ambient Temperature ◽  
High Velocity ◽  
Recirculation Zone ◽  
Ambient Pressure ◽  
Low Pressure ◽  
Ambient Conditions ◽  
Single Entity ◽  
Injection Duration ◽  
Pressure Region ◽  
Entrained Air

Abstract The plumes of a gasoline spray collapse into a single entity under the influence of ambient pressure, ambient temperature and injection duration. Previous work by the author studied experimentally [1] and numerically [2] the phenomenon of spray collapse. It was observed that the entrained air from every single plume, accumulatively creates a recirculation zone in the middle of the spray. The recirculation zone of high velocity, creates a low pressure region, which causes the collapse of the spray. In this paper, the influence of the number of plumes in the spray, is investigated numerically. The plume angle and ambient conditions matched Spray G, but the number of plumes was varied from two to eight. The effect of the plume number on the spray collapse was investigated numerically. It was evident that increased number of plumes in the spray promotes spray collapse.

scholarly journals DEVELOPMENT OF TECHNOLOGIES FOR NATURAL GAS AND BIOGAS UTILIZATION IN TRANSPORT / APSKATS PAR TRANSPORTA SEKTORĀ IZMANTOJAMĀM DABASGĀZES UN BIOGĀZES TEHNOLOĢIJĀM

2013 ◽  
Vol 50 (6) ◽  
pp. 26-35
Author(s):  
Y. Gelfgat ◽  
R. Smigins
Keyword(s):  
Air Quality ◽  
Natural Gas ◽  
Internal Combustion Engines ◽  
Fossil Fuels ◽  
Internal Combustion ◽  
Transportation Costs ◽  
Combustion Engines ◽  
Gaseous Fuels ◽  
Gas Utilization

Abstract Popularity of methane-containing gaseous fuels has slowly been growing since their appearance, especially in the last decades. Occasional non-availability of liquid fossil fuels, the necessity to reduce the transportation costs and to improve the air quality are the basic factors which stimulated development of gas utilization technologies - from accumulation, compression and deflation of gas to its usage in internal combustion engines. Since then different solutions have been offered, and the authors are reviewing them - from the first use of natural gas to nowadays.

scholarly journals Single Droplet Combustion Characteristics of Petroleum Diesel- Philippine Tung Biodiesel Blends

2021 ◽  
Vol 18 (24) ◽  
pp. 1409
Author(s):  
Nurkholis Hamidi ◽  
Joko Nugroho
Keyword(s):  
Burning Rate ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Ambient Pressure ◽  
Flame Temperature ◽  
Combustion Characteristics ◽  
Chamber Pressure ◽  
Droplet Combustion ◽  
Fuel Blends

The purpose of the present study is to investigate the effects of fuel blending of petroleum diesel and biodiesel made from Philippine Tung on the combustion characteristics of fuel droplets. In this study, petroleum diesel was mixed with biodiesel at volume percentages of 0 to 100 % to produce 5 fuel blends. The ratios of fuel blends (petroleum volume/biodiesel volume) were 100:0 (P100), 75:25 (BP25), 50:50 (BP50), 25:75 (BP75) and 0:100 (B100). Single droplet combustion experiments were prepared to understand the combustion characteristics at 3 levels of ambient pressure (100, 200 and 300 kPa). Observations were carried out on the ignition delay time, the burning rate constant, droplet temperature, and the flame visualization. The results showed some effects of the adding of biodiesel in petroleum diesel and the chamber pressure on droplet combustion characteristics.  The adding of biodiesel into petroleum diesel resulted in a shorter ignition delay time and higher burning rate constants. But, the lower heating value of biodiesel caused the lower flame temperature. The possibility of micro-explosion also increased due to the mixing of fuel. On the other hand, increasing the chamber pressure also resulted in shorter ignition delay, higher burning rate, and higher combustion temperature. The higher ambient pressure also compressed the flame dimension and enhanced the onset of micro-explosion. HIGHLIGHTS The adding of biodiesel into petroleum diesel with different physical and chemical properties impacts the droplet combustion behavior, especially on the characteristics of burning rate, ignition delay time, flame temperature, and micro explosion The high content of unsaturated fatty acids and oxygen in Philippine Tung biodiesel improves the ignition delay time and burning rate constants of the blended fuel, but, the lower heating value causes the lower flame temperature The multi-components of fatty acids with different boiling points in Philippine Tung oil promote the micro-explosion in the combustion of the mixtures of biodiesel and petroleum diesel fuel GRAPHICAL ABSTRACT

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