Performance Predictions of a Hydrogen-Enhanced Natural Gas HCCI Engine

2005 ◽  
Author(s):  
K. Raitanapaibule ◽  
K. Aung
Keyword(s):  
Natural Gas ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Ignition Time ◽  
Peak Temperature ◽  
Inlet Temperature ◽  
Hcci Combustion ◽  
Performance Predictions ◽  
Temperature And Pressure

The characteristics of HCCI engines were numerically investigated by CHEMKIN software, CHEMKIN 4.0. Cylinder temperature and pressure, ignition delay time, peak temperature and pressure, indicated work, indicated power and IMEP were performed for the analysis the HCCI combustion of Methane and Hydrogen. The natural gas can be represented as the Methane (CH4), which is the main ingredient. The simulation evaluations were done by increasing the initial concentrations of H2, changing the initial temperature (inlet temperature), or varying the equivalence ratio. The numerical simulations were accomplished using CHEMKIN Suite from Reaction Design and the results are focused on ignition time, peak temperature, and indicated power. The effect of hydrogen addition to methane increases peak temperature and pressure, decreases ignition delay time, and increases indicated power.

Ignition Studies of C1–C7 Natural Gas Blends at Gas-Turbine Relevant Conditions

2020 ◽  
Author(s):  
Amrit Bikram Sahu ◽  
A. Abd El-Sabor Mohamed ◽  
Snehasish Panigrahy ◽  
Gilles Bourque ◽  
Henry Curran
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Gas Mixtures ◽  
Auto Ignition ◽  
Wide Range ◽  
Detailed Kinetic Model ◽  
Sensitization Effect

Abstract New ignition delay time measurements of natural gas mixtures enriched with small amounts of n-hexane and n-heptane were performed in a rapid compression machine to interpret the sensitization effect of heavier hydrocarbons on auto-ignition at gas-turbine relevant conditions. The experimental data of natural gas mixtures containing alkanes from methane to n-heptane were carried out over a wide range of temperatures (840–1050 K), pressures (20–30 bar), and equivalence ratios (φ = 0.5 and 1.5). The experiments were complimented with numerical simulations using a detailed kinetic model developed to investigate the effect of n-hexane and n-heptane additions. Model predictions show that the addition of even small amounts (1–2%) of n-hexane and n-heptane can lead to increase in reactivity by ∼40–60 ms at compressed temperature (TC) = 700 K. The ignition delay time (IDT) of these mixtures decrease rapidly with an increase in concentration of up to 7.5% but becomes almost independent of the C6/C7 concentration beyond 10%. This sensitization effect of C6 and C7 is also found to be more pronounced in the temperature range 700–900 K compared to that at higher temperatures (> 900 K). The reason is attributed to the dependence of IDT primarily on H2O2(+M) ↔ 2ȮH(+M) at higher temperatures while the fuel dependent reactions such as H-atom abstraction, RȮ2 dissociation or Q.OOH + O2 reactions are less important compared to 700–900 K, where they are very important.

Experimental Study and Modeling of Autoignition of Natural Gas/Air-Mixtures Under Gas Turbine Relevant Conditions

2005 ◽  
Author(s):  
Andreas Koch ◽  
Clemens Naumann ◽  
Wolfgang Meier ◽  
Manfred Aigner
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Ignition Delay ◽  
Delay Time ◽  
High Speed ◽  
Ignition Delay Time ◽  
Evaluation Procedure ◽  
Ignition Process ◽  
Ignition Delay Times ◽  
Delay Times

The objective of this work was the improvement of methods for predicting autoignition in turbulent flows of different natural gas mixtures and air. Measurements were performed in a mixing duct where fuel was laterally injected into a turbulent flow of preheated and pressurized air. To study the influence of higher order hydrocarbons on autoignition, natural gas was mixed with propane up to 20% by volume at pressures up to 15 bar. During a measurement cycle, the air temperature was increased until autoignition occurred. The ignition process was observed by high-speed imaging of the flame chemiluminescence. In order to attribute a residence time (ignition delay time) to the locations where autoignition was detected the flow field and its turbulent fluctuations were simulated by numerical codes. These residence times were compared to calculated ignition delay times using detailed chemical simulations. The measurement system and data evaluation procedure are described and preliminary results are presented. An increase in pressure and in fraction of propane in the natural gas both reduced the ignition delay time. The measured ignition delay times were systematically longer than the predicted ones for temperatures above 950 K. The results are important for the design process of gas turbine combustors and the studies also demonstrate a procedure for the validation of design tools under relevant conditions.

Ignition and Oxidation of 50/50 Butane Isomer Blends

2009 ◽  
Author(s):  
Nicole Donato ◽  
Christopher Aul ◽  
Eric Petersen ◽  
Christopher Zinner ◽  
Henry Curran ◽  
...  
Keyword(s):  
Shock Tube ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Ignition Time ◽  
Pressure Rise ◽  
Time Data ◽  
Kinetics Modeling ◽  
Time Sensitivity ◽  
Wide Range

One of the alkanes found within gaseous fuel blends of interest to gas turbine applications is butane. There are two structural isomers of butane, normal butane and iso-butane, and the combustion characteristics of either isomer are not well known. Of particular interest to this work are mixtures of n-butane and iso-butane. A shock-tube experiment was performed to produce important ignition delay time data for these binary butane isomer mixtures which are not currently well studied, with emphasis on 50–50 blends of the two isomers. These data represent the most extensive shock-tube results to date for mixtures of n-butane and iso-butane. Ignition within the shock tube was determined from the sharp pressure rise measured at the endwall which is characteristic of such exothermic reactions. Both experimental and kinetics modeling results are presented for a wide range of stoichiometry (φ = 0.3–2.0), temperature (1056–1598 K), and pressure (1–21 atm). The results of this work serve as validation for the current chemical kinetics model. Correlations in the form of Arrhenius-type expressions are presented which agree well with both the experimental results and the kinetics modeling. The results of an ignition-delay-time sensitivity analysis are provided, and key reactions are identified. The data from this study are compared with the modeling results of 100% normal butane and 100% iso-butane. The 50/50 mixture of n-butane and iso-butane was shown to be more readily ignitable than 100% iso-butane but reacts slower than 100% n-butane only for the richer mixtures. There was little difference in ignition time between the lean mixtures.

Ignition Delay Time Correlation of C1 – C5 Natural Gas Blends for Intermediate and High Temperature Regime

2021 ◽  
Author(s):  
A. Abd El-Sabor Mohamed ◽  
Amrit Bikram Sahu ◽  
Snehasish Panigrahy ◽  
Gilles Bourque ◽  
Henry Curran
Keyword(s):  
Natural Gas ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Correlation Equation ◽  
Time Correlation ◽  
Reflected Shock ◽  
Global Correlation ◽  
Rate Form ◽  
Good Agreement

Abstract New ignition delay time (IDT) data for stoichiometric natural gas (NG) blends composed of C1 – C5 n-alkanes with methane as the major component were recorded using a high pressure shock tube (ST) at reflected shock pressures (p5) and temperatures (T5) in the range 20–30 bar and 1000–1500 K, respectively. The good agreement of the new IDT experimental data with literature data shows the reliability of the new data at the conditions investigated. Comparisons of simulations using the NUI Galway mechanism (NUIGMech1.0) show very good agreement with the new experimental results and with the existing data available in the literature. Empirical IDT correlation equations have been developed through multiple linear regression analyses for these C1 – C5 n-alkane/air mixtures using constant volume IDT simulations in the pressure range pC = 10–50 bar, at temperatures TC = 950–2000 K and in the equivalence ratio (φ) range 0.3–3.0. Moreover, a global correlation equation is developed using NUIGMech1.0, to predict the IDTs for these NG mixtures and other relevant data available in the literature. The correlation expression utilized in this study employs a traditional Arrhenius rate form including dependencies on the individual fuel fraction, TC, φ and pC.

Numerical Simulation of the Plasma-Assisted Combustion of Methane HCCI

2013 ◽  
Vol 385-386 ◽  
pp. 19-22
Author(s):  
Hui Chun Wang ◽  
Chun Mei Wang ◽  
Su Wei Zhu ◽  
Xiao Liu
Keyword(s):  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Volume Fraction ◽  
Zone Model ◽  
Discharge Process ◽  
Lean Burn ◽  
Lean Combustion ◽  
Hcci Combustion ◽  
Homogenous Charge Compression Ignition

To enhance the lean combustion of methane homogenous charge compression ignition (HCCI) engine and expand the lean-burn limit, a non-equilibrium plasma kinetic model has been used to study the discharge process of methane-air mixture numerically. The effect of the discharge productions on the methane HCCI combustion are studied numerically by using a CHEMKIN-based multi-zone model. The simulation results show that the discharge produced reactive radicals, such as H, O and CH3. These radicals can enhance the combustion of CH4 fueled HCCI significantly. Introduction of 1% (volume fraction of the fuel) of H reduces the ignition delay time of HCCI combustion (with equivalence fuel / air ratio of Φ = 0.5) by about 13 crank angle degrees (°CA), adding the same amount of O reduces the ignition delay time by about 10°CA. Further research shows that, with the increase in the above radicals, the combustion enhancement becomes stronger.

scholarly journals Influence of high ethane content on natural gas ignition

2019 ◽  
Vol 16 (1) ◽  
pp. 36-42
Author(s):  
Hernando Alexander Yepes-Tumay ◽  
Arley Cardona-Vargas
Keyword(s):  
Natural Gas ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Fuel Mixture ◽  
Ignition Limit ◽  
Mode Analysis ◽  
Gas Combustion ◽  
Gas Ignition ◽  
Natural Gas Combustion

The effect of ethane on combustion and natural gas autoignition was studied in the present paper. Two fuel mixture of natural gas with high ethane content were considered, 75% CH4 – 25% C2H6 (mixture 1), and 50% CH4 – 50% C2H6 (mixture 2). Natural gas combustion incidence was analyzed through the calculation of energy properties and the ignition delay time numerical calculations along with an ignition mode analysis. Specifically, the strong ignition limit was calculated to determine the effect of ethane on natural gas autoignition. According to the results, ignition delay time decreases for both mixtures in comparison with pure methane. The strong ignition limit shifts to lower temperatures when ethane is present in natural gas chemical composition.  

scholarly journals Simulation of ignition delay time of compressed natural gas combustion

2015 ◽  
Vol 12 ◽  
pp. 3125-3140
Author(s):  
Yuswan Muharam ◽  
◽  
Mirza Mahendra ◽  
Dinda Gayatri ◽  
Sutrasno Kartohardjono ◽  
...  
Keyword(s):  
Natural Gas ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Compressed Natural Gas ◽  
Gas Combustion ◽  
Natural Gas Combustion

N-heptane ignition delay time with temperature criterion for HCCI combustion

Fuel ◽  
2018 ◽  
Vol 225 ◽  
pp. 483-489 ◽  
Author(s):  
Fadila Maroteaux ◽  
Bianca Maria Vaglieco ◽  
Ezio Mancaruso
Keyword(s):  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Hcci Combustion ◽  
Temperature Criterion

scholarly journals Chemical Kinetic Model of Multicomponent Gasoline Surrogate Fuel with Nitric Oxide in HCCI Combustion

Molecules ◽  
2020 ◽  
Vol 25 (10) ◽  
pp. 2273
Author(s):  
Chao Yang ◽  
Zhaolei Zheng
Keyword(s):  
Nitric Oxide ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Chemical Kinetic ◽  
Model Verification ◽  
Chemical Kinetic Model ◽  
Hcci Combustion ◽  
Surrogate Fuel ◽  
Simplified Mechanism

This study presents a simplified mechanism of a five-component gasoline surrogate fuel (TDRF–NO) that includes n-heptane, isooctane, toluene, diisobutylene (DIB) and nitric oxide (NO). The mechanism consists of 119 species and 266 reactions and involves TDRF and NO submechanisms. Satisfactory results were obtained in simulating HCCI combustion in engines. The TDRF submechanism is based on the simplified mechanism of toluene reference fuel (TRF) and adds DIB to form quaternary surrogate fuel for gasoline. A simplified NO submechanism containing 33 reactions was added to the simplified mechanism of TDRF, considering the effect of active molecular NO on the combustion of gasoline fuel. The ignition delay data of the shock tube under different pressure and temperature conditions verified the validity of the model. Model verification results showed that the ignition delay time predicted by the simplified mechanism and its submechanics were consistent with the experimental data. The addition of NO caused the ignition delay time of the mechanism simulation to advance with increasing concentration of NO added. The established simplified mechanism effectively predicted the actual combustion and ignition of gasoline.

Ignition of Lean Methane-Based Fuel Blends at Gas Turbine Pressures

2007 ◽  
Vol 129 (4) ◽  
pp. 937-944 ◽  
Author(s):  
Eric L. Petersen ◽  
Joel M. Hall ◽  
Schuyler D. Smith ◽  
Jaap de Vries ◽  
Anthony R. Amadio ◽  
...  
Keyword(s):  
Activation Energy ◽  
Temperature Dependence ◽  
Gas Turbine ◽  
Chemical Kinetics ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Ignition Time ◽  
Fuel Blends ◽  
Reflected Shock

Shock-tube experiments and chemical kinetics modeling were performed to further understand the ignition and oxidation kinetics of lean methane-based fuel blends at gas turbine pressures. Such data are required because the likelihood of gas turbine engines operating on CH4-based fuel blends with significant (>10%) amounts of hydrogen, ethane, and other hydrocarbons is very high. Ignition delay times were obtained behind reflected shock waves for fuel mixtures consisting of CH4, CH4∕H2, CH4∕C2H6, and CH4∕C3H8 in ratios ranging from 90/10% to 60/40%. Lean fuel/air equivalence ratios (ϕ=0.5) were utilized, and the test pressures ranged from 0.54 to 30.0atm. The test temperatures were from 1090K to 2001K. Significant reductions in ignition delay time were seen with the fuel blends relative to the CH4-only mixtures at all conditions. However, the temperature dependence (i.e., activation energy) of the ignition times was little affected by the additives for the range of mixtures and temperatures of this study. In general, the activation energy of ignition for all mixtures except the CH4∕C3H8 one was smaller at temperatures below approximately1300K(∼27kcal∕mol) than at temperatures above this value (∼41kcal∕mol). A methane/hydrocarbon–oxidation chemical kinetics mechanism developed in a recent study was able to reproduce the high-pressure, fuel-lean data for the fuel/air mixtures. The results herein extend the ignition delay time database for lean methane blends to higher pressures (30atm) and lower temperatures (1100K) than considered previously and represent a major step toward understanding the oxidation chemistry of such mixtures at gas turbine pressures. Extrapolation of the results to gas turbine premixer conditions at temperatures less than 800K should be avoided however because the temperature dependence of the ignition time may change dramatically from that obtained herein.

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