scholarly journals Ignition Process and Flame Lift-Off Characteristics of dimethyl ether (DME) Reacting Spray

2021 ◽  
Vol 7 ◽  
Author(s):  
Khanh Duc Cung ◽  
Ahmed Abdul Moiz ◽  
Xiucheng Zhu ◽  
Seong-Young Lee
Keyword(s):  
Dimethyl Ether ◽  
Alternative Fuels ◽  
Chemical Properties ◽  
Injection Pressure ◽  
High Reactivity ◽  
Combustion Characteristic ◽  
Spray Combustion ◽  
Ignition Process ◽  
Compression Ignition ◽  
Lift Off

Advanced combustion systems that utilize different combustion modes and alternative fuels have significantly improved combustion performance and emissions compared to conventional diesel or spark-ignited combustions. As an alternative fuel, dimethyl ether (DME) has been receiving much attention as it runs effectively under low-temperature combustion (LTC) modes such as homogeneous charge compression ignition (HCCI) and reactivity control combustion ignition (RCCI). Under compression-ignition (CI), DME can be injected as liquid fuel into a hot chamber, resulting in a diesel-like spray/combustion characteristic. With its high fuel reactivity and unique chemical formula, DME ignites easily but produces almost smokeless combustion. In the current study, DME spray combustion under several different conditions of ambient temperature (Tamb = 750–1100 K), ambient density (ρamb = 14.8–30 kg/m3), oxygen concentration (O2 = 15–21%), and injection pressure (Pinj = 75–150 MPa) were studied. The results from both experiments (constant-volume combustion vessel) and numerical simulations were used to develop empirical correlations for ignition and lift-off length. Compared to diesel, the established correlation of DME shows a similar Arrhenius-type expression. Sensitivity studies show that Tamb and Pinj have a stronger effect on DME's ignition and combustion than other parameters. Finally, this study provides a simplified conceptual mechanism of DME reacting spray under high reactivity ambient (high Tamb, high O2) and LTC conditions. Finally, this paper discusses engine operating strategies using a non-conventional fuel such as DME with different reactivity and chemical properties.

The Study on PCCI Mode of Diesel Engine Fueled with Methanol/Dimethyl Ether

2014 ◽  
Vol 607 ◽  
pp. 629-632
Author(s):  
Yan Yan ◽  
Yu Sheng Zhang
Keyword(s):  
Dimethyl Ether ◽  
Alternative Fuels ◽  
Volume Fraction ◽  
Good Alternative ◽  
Diffusion Combustion ◽  
Compression Ignition ◽  
Temperature Reaction ◽  
High Temperature Reaction ◽  
Three Stages ◽  
And Diffusion

Taking into account China's abundant coal resources, methanol and DME(Dimethyl Ether) obtained from coal are good alternative fuels. The research project is to utilize the fuel of DME and methanol in diesel engines for new combustion models PCCI (Premixed Charge Compression Ignition).The tests of the PCCI mode with different boundary conditions were studied on PCCI test bench. PCCI combustion is consisted of three stages: low temperature reaction of DME, high-temperature reaction of DME and diffusion combustion reaction of methanol. DME as combustion improver should be kept relatively low concentration, and with the decrease of methanol, its concentration need to be reduced. Methanol and formaldehyde are important parts of HC emission, their volume fraction was about 70%.

Effect of Fuel Injection Pressure and Premixed Ratio on Mineral Diesel-Methanol Fueled Reactivity Controlled Compression Ignition Mode Combustion Engine

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Akhilendra Pratap Singh ◽  
Nikhil Sharma ◽  
Dev Prakash Satsangi ◽  
Avinash Kumar Agarwal
Keyword(s):  
Fuel Injection ◽  
Combustion Engine ◽  
Engine Performance ◽  
Injection Pressure ◽  
High Reactivity ◽  
Compression Ignition ◽  
Oxides Of Nitrogen ◽  
Reactivity Controlled Compression Ignition ◽  
Hc Emissions ◽  
Fuel Injection Pressure

Abstract Reactivity controlled compression ignition (RCCI) mode combustion has attracted significant attention because of its superior engine performance and significantly lower emissions of oxides of nitrogen (NOx) and particulate matter (PM) compared with conventional compression ignition (CI) mode combustion engines. In this experimental study, effects of fuel injection pressure (FIP) of high reactivity fuel (HRF) and premixed ratio of low reactivity fuel (LRF) were evaluated on a diesel-methanol fueled RCCI mode combustion engine. Experiments were performed in a single cylinder research engine at a constant engine speed (1500 rpm) and constant engine load (3 bar BMEP) using three different FIPs (500, 750, and 1000 bar) of mineral diesel and four different premixed ratios (rp = 0, 0.25, 0.50, and 0.75) of methanol. Results showed that RCCI mode resulted in more stable combustion compared with baseline CI mode combustion. Increasing FIP resulted in relatively higher knocking, but it reduced with increasing premixed ratio. Relatively higher brake thermal efficiency (BTE) of RCCI mode combustion compared with baseline CI mode combustion is an important finding of this study. BTE increased with increasing FIP of mineral diesel and increasing premixed ratio of methanol. Relatively dominant effect of increasing FIP on BTE at higher premixed ratios of methanol was also an important finding of this study. RCCI mode combustion resulted in higher carbon monoxide (CO) and hydrocarbon (HC) emissions, but lower PM and NOx emissions compared with baseline CI mode combustion. Increasing FIP of HRF at lower premixed ratios reduced the number concentration of particles; however, effect of FIP became less dominant at higher premixed ratios. Relatively higher number emissions of nanoparticles at higher FIPs were observed. Statistical and qualitative correlations exhibited the importance of suitable FIP at different premixed ratios of LRF on emission characteristics of RCCI mode combustion engine.

Modeling spray combustion using multi-component surrogate fuels

2021 ◽  
pp. 095765092110025
Author(s):  
Tao Yang ◽  
Ran Yi ◽  
Qiaoling Wang ◽  
Chien-Pin Chen
Keyword(s):  
Chemical Properties ◽  
Kinetic Mechanism ◽  
Chemical Kinetic ◽  
Spray Combustion ◽  
Surrogate Fuels ◽  
Diesel Fuels ◽  
Constant Volume Chamber ◽  
Kinetic Mechanisms ◽  
Lift Off ◽  
Evaporation Models

Kerosene and diesel fuels involved in spray combustion operations are complex fuels composed of a wide and diverse variety of hydrocarbon components. For practical numerical modeling of the evaporation and combustion phenomena in a combustor, well-designed surrogates fuels that can mimic the real fuel thermal and chemical properties can be utilized. In this study, predictions and validations of the influence of fuel on the liquid and vapor penetration characteristics within a constant-volume chamber were first performed utilizing a benchmark m-xylene/ n-dodecane, Jet-A, and diesel surrogate fuels. Then, simulations of reacting spray of a bi-component m-xylene/ n-dodecane fule, and a four-component Jet-A surrogate fuel ( n-dodecane (C12H26), iso-cetane (C16H34), trans-decalin (C10H18) and toluene (C7H8)) were studied aided by skeleton chemical kinetic mechanisms available from the literature. The results of ignition delay time, lift-off length, radicals, and the mass fraction histories of fuel species were comprehensively used to assess the performance of relevant thermophysical and chemical sub-models. Two different chemical mechanisms were compared in detail to investigate the effect of the chemical kinetics model on the flame structures and spray characteristics. It has been found that the spray ignition of multi-component fuels is remarkably influenced by the chosen chemical kinetic mechanism and less affected by the droplet evaporation models.

Experimental Study on Emission Characteristics of HCCI Operation with N-Heptane

2013 ◽  
Vol 710 ◽  
pp. 290-293
Author(s):  
Ye Chun Shen ◽  
Jing Lei Zhou ◽  
Chun Hua Zhang ◽  
Jiao Wang
Keyword(s):  
Homogeneous Charge Compression Ignition ◽  
Cetane Number ◽  
Chemical Properties ◽  
Ignition Process ◽  
Compression Ignition ◽  
Hcci Combustion ◽  
Excess Air ◽  
Theoretical Investigations ◽  
Excess Air Coefficient ◽  
Homogeneous Charge

Homogeneous Charge Compression Ignition (HCCI) is a new combustion mode with higher thermal efficiency and lower emission. With the recent development of experimental and theoretical investigations, HCCI operation for high cetane number fuels has attracted more attention. As a reference fuel, n-heptane is very easy to be ignited for high cetane number and shows obviously two-stage heat release in homogeneous charge compression ignition process due to chemical properties. HC, CO and NOx emissions of n-heptane HCCI combustion with intake temperature and excess air coefficient are studied in this paper. Intake temperature and excess air coefficient have a great impact on HCCI combustion and provide important approaches to widen HCCI operating range.

scholarly journals Review on the Use of Diesel–Biodiesel–Alcohol Blends in Compression Ignition Engines

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1194 ◽  
Author(s):  
Rodica Niculescu ◽  
Adrian Clenci ◽  
Victor Iorga-Siman
Keyword(s):  
Alternative Fuels ◽  
Fossil Fuels ◽  
Combustion Engine ◽  
Ghg Emissions ◽  
Chemical Properties ◽  
Internal Combustion ◽  
Compression Ignition ◽  
Engine Operation ◽  
Performance And Emissions ◽  
Ci Engines

The use of alternative fuels contributes to the lowering of the carbon footprint of the internal combustion engine. Biofuels are the most important kinds of alternative fuels. Currently, thanks to the new manufacturing processes of biofuels, there is potential to decrease greenhouse gas (GHG) emissions, compared to fossil fuels, on a well-to-wheel basis. Amongst the most prominent alternative fuels to be used in mixtures/blends with fossil fuels in internal combustion (IC) engines are biodiesel, bioethanol, and biomethanol. With this perspective, considerable attention has been given to biodiesel and petroleum diesel fuel blends in compression ignition (CI) engines. Many studies have been conducted to assess the impacts of biodiesel use on engine operation. The addition of alcohols such as methanol and ethanol is also practised in biodiesel–diesel blends, due to their miscibility with the pure biodiesel. Alcohols improve the physico-chemical properties of biodiesel–diesel blends, which lead to improved CI engine operation. This review paper discusses some results of recent studies on biodiesel, bioethanol, and biomethanol production, their physicochemical properties, and also, on the influence of the use of diesel–biodiesel–alcohols blends in CI engines: combustion characteristics, performance, and emissions.

scholarly journals Spray and Combustion Characterizations of Acetone-Butanol-Ethanol (ABE) blend at High-Pressure and High-Temperature Conditions

2017 ◽  
Author(s):  
Nilaphai Ob ◽  
Ajrouche Hugo ◽  
Hespel Camille ◽  
Moreau Bruno ◽  
Chanchaona Somchai ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Ambient Pressure ◽  
Chemical Properties ◽  
Volume Ratio ◽  
Spray Combustion ◽  
Pure Nitrogen ◽  
Ambient Temperatures ◽  
Lift Off ◽  
Ci Engines

The intermediate fermentation mixture of butanol production, Acetone, Butanol and Ethanol (ABE), is increasinglyconsidered as a new alternative fuel in CI engines due to its physical and chemical properties, which are similar to those of butanol, and its advantages of no additional cost or energy consumption due to butanol separation. In a previous study, the High-Pressure and High-Temperature (HPHT) chamber, called ‘New One Shot Engine” (NOSE), was used to investigate macroscopic spray-combustion parameters by validating Spray-A conditions of the Engine Combustion Network. The present study concerns the spray-combustion characteristics of the ABE mixture (volume ratio 3:6:1), blended with n-dodecane at a volumetric ratio of 20% (ABE20), compared to n-dodecane as reference fuel. The macroscopic spray and combustion parameters were investigated, for non-reactive conditions, in pure Nitrogen and for reactive conditions, in 15% oxygen, at ambient pressure (60 bar), ambient density (22.8 kg/m3) and different ambient temperatures (800 K, 850 K and 900 K). The liquid and vapor spray penetrations were investigated by the Diffused Back Illumination (DBI) and Schlieren techniques in non-reactive conditions. In reactive conditions, the lift-off length was measured by OH* chemiluminescence images at 310 nm. The Schlieren technique was also used to verify the choice of detection criterion. The ignition delay results of the two fuels were compared. It was found that the behavior of the two fuels as a function of temperature was similar even if the liquid length of ABE20 was shorter than that of n-dodecane at all ambient temperatures. On the other hand, no real difference in vapor spray penetration between the two fuels was observed. The vaporization properties and the lower auto-ignition ability of ABE20 led to longer ignition delays and lift-off length.DOI: http://dx.doi.org/10.4995/ILASS2017.2017.4852

scholarly journals Combustion Phenomena, Emissions and Performance Characteristics of Lemongrass Oil in Direct Injection (DI) Compression Ignition Diesel

2019 ◽  
Vol 8 (2) ◽  
pp. 2380-2386
Keyword(s):  
Diesel Engine ◽  
Alternative Fuels ◽  
Direct Injection ◽  
Performance Characteristics ◽  
Ignition Process ◽  
Compression Ignition ◽  
Oil Blends ◽  
Cymbopogon Flexuosus ◽  
Lemongrass Oil ◽  
And Performance

Development of alternative fuels used in IC engines employ traditionally advance process which creates a fuel related issues, decisive fuel properties are indentified and their specific values are defined to solve problem. The present work deals with lemongrass oil (cymbopogon flexuosus) as an alternative fuel. By using trans-esterification process the lemongrass oil converted into biodiesel. This biodiesel is blended with the conventional diesel with various proportions and tests were conducted on 20%, 30% and 50% lemongrass oil blends with diesel. The performance characteristics, emissions and combustion phenomena are studied at 1500rpm of engine speed and compression ratio of 17.5 in a 4- stroke cycle mono cylinder DI compression ignition diesel engine. Comparison studies are made with conventional diesel fuel. Experimental outcomes revealed the successful ignition process in which the heat energy released from a DI compression ignition diesel engine fueled with lemon grass oil is within the limits.

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