scholarly journals The Effect of Initial Conditions on the Laminar Burning Characteristics of Natural Gas Diluted by CO2

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2892 ◽  
Author(s):  
Zhiqiang Han ◽  
Zhennan Zhu ◽  
Peng Wang ◽  
Kun Liang ◽  
Zinong Zuo ◽  
...  
Keyword(s):  
Natural Gas ◽  
Dilution Rate ◽  
Initial Temperature ◽  
Initial Conditions ◽  
Burning Velocity ◽  
Initial Pressure ◽  
Chemical Kinetic ◽  
Laminar Burning Velocity ◽  
Flame Instability ◽  
Highly Correlated

The initial conditions such as temperature, pressure and dilution rate can have an effect on the laminar burning velocity of natural gas. It is acknowledged that there is an equivalent effect on the laminar burning velocity between any two initial conditions. The effects of initial temperatures (323 K–423 K), initial pressures (0.1 MPa–0.3 MPa) and dilution rate (0–16%, CO2 as diluent gas) on the laminar burning velocity and the flame instability were investigated at a series of equivalence ratios (0.7–1.2) in a constant volume chamber. A chemical kinetic simulation was also conducted to calculate the laminar burning velocity and essential radicals’ concentrations under the same initial conditions. The results show that the laminar burning velocity of natural gas increases with initial temperature but decreases with initial pressure and dilution rate. The maximum concentrations of H, O and OH increase with initial temperature but decrease with initial pressure and dilution rate. Laminar burning velocity is highly correlated with the sum of the maximum concentration of H and OH.

scholarly journals The Equivalent Effect of Initial Condition Coupling on the Laminar Burning Velocity of Natural Gas Diluted by CO2

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 809
Author(s):  
Xueshun Wu ◽  
Peng Wang ◽  
Zhennan Zhu ◽  
Yunshou Qian ◽  
Wenbin Yu ◽  
...  
Keyword(s):  
Dilution Rate ◽  
Initial Temperature ◽  
Coupling Effect ◽  
Burning Velocity ◽  
Initial Pressure ◽  
Rate Of Change ◽  
Equal Weight ◽  
Initial Condition ◽  
Laminar Burning Velocity ◽  
Equivalent Effect

Initial temperature has a promoting effect on laminar burning velocity, while initial pressure and dilution rate have an inhibitory effect on laminar burning velocity. Equal laminar burning velocities can be obtained by initial condition coupling with different temperatures, pressures and dilution rates. This paper analysed the equivalent distribution pattern of laminar burning velocity and the variation pattern of an equal weight curve using the coupling effect of the initial pressure (0.1–0.3 MPa), initial temperature (323–423 K) and dilution rate (0–16%). The results show that, as the initial temperature increases, the initial pressure decreases and the dilution rate decreases, the rate of change in laminar burning velocity increases. The equivalent effect of initial condition coupling can obtain equal laminar burning velocity with an dilution rate increase (or decrease) of 2% and an initial temperature increase (or decrease) of 29 K. Moreover, the increase in equivalence ratio leads to the rate of change in laminar burning velocity first increasing and then decreasing, while the increases in dilution rate and initial pressure make the rate of change in laminar burning velocity gradually decrease and the increase in initial temperature makes the rate of change in laminar burning velocity gradually increase. The area of the region, where the initial temperature influence weight is larger, gradually decreases as the dilution rate increases, and the rate of decrease gradually decreases.

Laminar Flame Speed Measurements of Hydrogen/Natural Gas Mixtures for Gas Turbine Applications

2021 ◽  
Author(s):  
Gihun Kim ◽  
Ritesh Ghorpade ◽  
Subith S. Vasu
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Laminar Flame ◽  
Burning Velocity ◽  
Nox Reduction ◽  
Pressure Rise ◽  
Initial Pressure ◽  
Chemical Kinetic ◽  
Experimental Conditions ◽  
Fuel Blend

Abstract Due to the increasingly challenging carbon emission reduction targets, hydrogen-containing fuel combustion is gaining the energy community’s attention, as highlighted recently in the U.S. Department of Energy’s (DOE) Hydrogen Program Plan [1]. Though fundamental and applied research of hydrogen-containing fuels has been a topic of research for several decades, there are knowledge-gaps and unexplored fuel blend combustion characteristics at conditions relevant to modern gas turbine combustors. Hydrogen will be burned directly or as mixtures with natural gas (NG) and/or ammonia (NH3) in these devices. Fundamental research on the combustion of hydrogen (H2) containing fuels is still essential, especially to overcome or accurately predict challenges such as nitrogen oxides (NOx) reduction and flashback and develop fuel flexible combustors for a prosperous hydrogen economy. We focused our investigation on a natural gas and hydrogen mixture. Measurements of laminar burning velocity (LBV) are necessary for these fuels to understand their applicability in the turbines and other engines. In this study, the maximum rate of pressure rise and LBV of methane (CH4), CH4/H2, natural gas, and natural gas/H2 mixture were measured in synthetic air. The experimental conditions were at an initial pressure of 1 atm and an initial temperature of 300 K. A realistic natural gas composition from the field was used in this study and consisted of CH4 and other alkanes. The experimental data were compared with simulations carried out with detailed chemical kinetic mechanisms.

scholarly journals Laminar Burning Velocities of Hydrogen-Blended Methane–Air and Natural Gas–Air Mixtures, Calculated from the Early Stage of p(t) Records in a Spherical Vessel

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7556
Author(s):  
Maria Mitu ◽  
Domnina Razus ◽  
Volkmar Schroeder
Keyword(s):  
Natural Gas ◽  
Initial Conditions ◽  
Numerical Study ◽  
Early Stage ◽  
Linear Trend ◽  
Burning Velocity ◽  
Pressure Rise ◽  
Spherical Vessel ◽  
Practical Applications ◽  
Hydrogen Addition

The flammable hydrogen-blended methane–air and natural gas–air mixtures raise specific safety and environmental issues in the industry and transportation; therefore, their explosion characteristics such as the explosion limits, explosion pressures, and rates of pressure rise have significant importance from a safety point of view. At the same time, the laminar burning velocities are the most useful parameters for practical applications and in basic studies for the validation of reaction mechanisms and modeling turbulent combustion. In the present study, an experimental and numerical study of the effect of hydrogen addition on the laminar burning velocity (LBV) of methane–air and natural gas–air mixtures was conducted, using mixtures with equivalence ratios within 0.90 and 1.30 and various hydrogen fractions rH within 0.0 and 0.5. The experiments were performed in a 14 L spherical vessel with central ignition at ambient initial conditions. The LBVs were calculated from p(t) data, determined in accordance with EN 15967, by using only the early stage of flame propagation. The results show that hydrogen addition determines an increase in LBV for all examined binary flammable mixtures. The LBV variation versus the fraction of added hydrogen, rH, follows a linear trend only at moderate hydrogen fractions. The further increase in rH results in a stronger variation in LBV, as shown by both experimental and computed LBVs. Hydrogen addition significantly changes the thermal diffusivity of flammable CH4–air or NG–air mixtures, the rate of heat release, and the concentration of active radical species in the flame front and contribute, thus, to LBV variation.

Laminar burning velocity of microalgae oil/RP-3 premixed flame at elevated initial temperature and pressure

Fuel ◽  
2022 ◽  
Vol 309 ◽  
pp. 122081
Author(s):  
Yu Liu ◽  
Wu Gu ◽  
Jinduo Wang ◽  
Hongan Ma ◽  
Nanhang Dong ◽  
...  
Keyword(s):  
Initial Temperature ◽  
Burning Velocity ◽  
Premixed Flame ◽  
Laminar Burning Velocity ◽  
Microalgae Oil ◽  
Temperature And Pressure

scholarly journals EXPERIMENTAL DETERMINATION OF LAMINAR BURNING VELOCITY OF BIOGAS AT PRESSURES UP TO 5 BAR

2018 ◽  
Vol 17 (2) ◽  
pp. 03
Author(s):  
L. Pizzuti ◽  
C. A. Martins ◽  
L. R. Santos
Keyword(s):  
Equivalence Ratio ◽  
Burning Velocity ◽  
Initial Pressure ◽  
Experimental Setup ◽  
Laminar Burning Velocity ◽  
Gaseous Mixtures ◽  
Experimental Procedure ◽  
Constant Volume Combustion Chamber ◽  
Percentage Standard Deviation

This paper presents a very detailed description of a new cylindrical constant volume combustion chamber designed for laminar burning velocity determination of gaseous mixtures at ambient temperature and initial pressure up to 6 bar. The experimental setup, the experimental procedure and the determination of the range of flame radius for laminar burning determination are all described in details. The laminar burning velocity of twelve synthetic biogas mixtures has been studied. Initial pressure varying between 1 and 5 bar, equivalence ratios, f, between 0.7 and 1.1 and percentage dilution, with a mixture of CO2 and N2, between 35 and 55% have been considered. Five experiments were run for each mixture providing a maximum percentage standard deviation of 8.11%. However, for two third of the mixtures this value is lower than 3.55%. A comparison with simulation using PREMIX for both GRI-Mech 3.0 and San Diego mechanisms has provided closer agreement for mixtures with equivalence ratio closer to stoichiometry whereas for f = 0.7 the deviation is larger than 15% for all pressures. Mixtures with lower equivalence ratio, higher dilution percentage and higher initial pressure presents the lower values of laminar burning velocity.

The Effects of Initial Conditions on the Composition of the On-Board Fuel Reformation Chamber in an HCCI Engine

2015 ◽  
Vol 733 ◽  
pp. 219-224
Author(s):  
Chun Hua Zhang ◽  
Le Xue
Keyword(s):  
Homogeneous Charge Compression Ignition ◽  
Initial Temperature ◽  
Initial Conditions ◽  
Initial Pressure ◽  
Compression Ignition ◽  
Fuel Reforming ◽  
Hcci Engine ◽  
Main Species ◽  
Fuel Reformation ◽  
Homogeneous Charge

Based on the CHEMKIN software, a model of the reforming chamber was built to simulate the on-board fuel reforming process in a Homogeneous Charge Compression Ignition (HCCI) engine. The effects of the initial pressure and temperature of the chamber on the reformed gas were studied. The results show that the main species in the reformed gas are H2 and CO. This paper investigated the effect of initial temperature on the reformed gas, in order to get the optimum initial temperature. Under the optimum initial temperature (1300 K), some important conclusions have been drawn by changing initial pressures of the chamber. Initial pressure may have great effect on other species, but has a small effect on mole fractions of H2 and CO. By comparing the concentrations of H2 and CO between low and high initial pressures under the optimum initial temperature, it can be concluded that H2 and CO are still the main species in the reformed gas.

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