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A new, reduced reaction mechanism for DME combustion in internal combustion engines is proposed. The new mechanism is based on a detailed DME mechanism suitable for low to high temperature ranges. The reduced model consists of 29 species and 66 reactions and contains a detailed H2/CO mechanism and reduced C1–C2 chemistry. The reduced mechanism inherits the major reaction pathways of the detailed mechanism,...
The intrinsic instability of laminar flame is one of the classic subjects in flame dynamics, which presents the dynamic response of laminar premixed flamelets to weak perturbations. The instabilities of laminar premixed CH4/H2/air flames stabilized on a non-adiabatic McKenna burner were investigated. The quantitative parameters of flame front were measured by OH-PLIF (Planar Laser Induced Fluorescence)...
Measurements on laminar flame speeds and ignition delay times of methane/air mixtures at elevated pressures and temperatures were carried out in a constant volume bomb and shock tube. The performances of GRI Mech 3.0, USC Mech II, and Aramco Mech 1.3 mechanisms were also evaluated from the data obtained. Results showed that the measured laminar flame speeds from the constant volume bomb by the linear...
Ignition delay times of 1-butene were measured behind reflected shock wave at the pressures of 1.2, 4.0, 16.0atm, in temperature range of 1000–1700K and equivalence ratios of 0.5, 1.0 and 2.0. Results show that ignition delay times exhibit the typical Arrhenius dependence on temperature, pressure, equivalence ratio and fuel concentration. A correlation was deduced from the experimental data. Comparison...
Effects of stretch and preferential diffusion on tip opening of laminar premixed Bunsen flames of syngas/air mixtures were investigated with experiments and numerical simulation. The reaction zone of the laminar flames at different hydrogen fractions (XH2=0.6, 0.8), equivalence ratios (φ=0.6–1.0) and Reynolds numbers (Re=1400, 1800) was obtained by OH-PLIF technique, while the species profile, velocity...
Cellular instability of non-adiabatic laminar premixed flat methane/hydrogen oxy-fuel flames highly diluted with CO 2 was studied systematically. The CH 4 /H 2 /CO 2 /O 2 flames were stabilized on a McKenna burner at atmospheric pressure. The CH 4 /H 2 /CO 2 /O 2 flames with varied equivalence ratios and hydrogen mole fractions...
Investigation on the characteristics of ion current in a direct-injection stratified-charge engine fueled with methanol was conducted. The test engine is a retrofitted 4-cylinder diesel engine with installation of a spark plug. Ion current was measured using the spark plug as ion sensor. Cylinder pressure was recorded and cylinder average temperature was calculated. The band-pass filtering and low-pass...
In this work, the spray and atomization characteristics of soybean biodiesel, di-n-butyl ether (DBE)/biodiesel blends and 0# diesel were investigated by using a high pressure common-rail injection system. The macroscopic spray characteristics such as the spray tip penetration (STP), the cone angle and the spray projected area were obtained from the spray images captured through high speed schlieren...
Ignition delay times of dimethyl carbonate were measured in a shock tube for the first time at T=1100–1600K, p=0.12–1.0MPa, fuel concentration=0.5–2.0%, and ϕ=0.5–2.0. A modified chemical kinetic model was developed and can well predict ignition delay times and activation energies. Further validation of the proposed kinetic model was made on the basis of the opposed flow diffusion flame data. Reasonable...
Laminar flame speeds of dimethyl ether/methane–air mixtures were measured in a constant volume combustion vessel at different initial temperatures (303–453K), initial pressures (0.1–0.7MPa), dilution ratios (0–25%), equivalence ratios (0.7–1.6) and over wide range of DME blending ratios (0–100%). Markstein lengths were also obtained at different blending ratios and equivalence ratios. Zhao DME model...
Laminar flame speeds of 2-methyl-1-butanol (2MB)–air mixture at temperatures of 393, 433 and 473K, pressures of 0.1, 0.25, 0.5 and 0.75MPa, and equivalence ratios of 0.6–1.8 were measured using the spherically propagating flame. Flame instabilities were analyzed using the Lewis number, flame thickness, density ratio and Markstein length combining with the schlieren photos. Flame instability is insensitive...
The influence of injection pressure up to ultra-high value of 300MPa, nozzle hole diameters of 0.16 and 0.08mm and fuel properties such as boiling point, cetane number and oxygen content on spray, ignition and combustion characteristics of biodiesel fuel in diesel engine were investigated. Biodiesel from palm oil source (BDF) and for comparison the JIS #2 diesel fuel were utilized. The Mie-scattering...
The structures of two laminar premixed n-heptane/O 2 /Ar flames (F1.60: Ф=1.60, C/O=0.51, and F1.80: Ф=1.80, C/O=0.57) and one laminar premixed n-heptane/methanol/O 2 /Ar flame (F1.80M: Ф=1.80, C/O=0.51) are studied at low pressure (4000Pa) by using synchrotron photoionization and molecular-beam sampling-mass spectrometry (PI-MBMS) techniques. Calculations are performed with a modified...
Experiments and computational simulations were used to study effects of diluents on laminar flame speeds of stoichiometric, laminar, premixed dimethyl ether (DME)/air flames. The experiments were conducted in a constant volume bomb under initial temperature of 298K and initial pressure of 0.1MPa. Outwardly propagating spherical flames were used to measure the laminar flame speeds of mixtures with...
2,5-Dimethylfuran, known as DMF, is a promising second-generation biofuel candidate. The potential of 2,5-dimethylfuran as an additive in iso-octane (used as gasoline fuel substitute in this study) was studied. Using outwardly spherical flame method and high speed schlieren photography, laminar burning characteristics of 2,5-dimethylfuran/iso-octane (20%/80% vol., designated as D20)/air mixtures were...
Experiments were conducted on a 4-cylinder direct-injection diesel engine using ultralow sulfur diesel blended with ethanol, biodiesel and diglyme to investigate the particulate emissions of the engine under five engine loads at the engine speed of 1800rpm. Four diesel–ethanol blends with oxygen concentrations of 2%, 4%, 6% and 8%, five diesel–biodiesel blends and five diesel–diglyme blends with oxygen...
An experimental study was conducted in a port fuel-injection, spark-ignition engine fuelled with blends of gasoline and n-butanol at different spark timings and EGR rates. The effect of spark timing, blend ratio and EGR rate on the emission characteristics (unburned hydrocarbon (HC), carbon monoxide (CO), nitrogen oxide (NO x ) and particulate size and distribution) was analyzed. BSFC (Brake...
The effect of fuel constituents and exhaust gas recirculation (EGR) on combustion characteristics, fuel efficiency and emissions of a direct injection diesel engine fueled with diesel-dimethoxymethane (DMM) blends was investigated experimentally. Three diesel-DMM blended fuels containing 20%, 30% and 50% by volume fraction of DMM, corresponding to 8.5%, 12.7% and 21.1% by mass of oxygen in the blends,...
Currently, bioethanol leads the automotive fuel market as the main substitute for gasoline in spark-ignition engines. However, worldwide interest has been triggered in the potential of 2,5-dimethylfuran, known as DMF, since the discovery of improved production methods. Although the energy content of DMF is comparable to that of gasoline, little is known about its combustion characteristics and emissions...
Combustion and emissions of a DI diesel engine fuelled with diesel-oxygenate blends were investigated. The results show that there exist the different behaviors in the combustion between the diesel-diglyme blends and the other five diesel-oxygenate blends as the diglyme has the higher cetane number than that of diesel fuel while the other five oxygenates have the lower cetane number than that of diesel...
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