scholarly journals EFFECT OF TEMPERATURE AND EXCESS AIR RATIO ON COMBUSTION PROCESS OF MIXTURES OF ERUCIC RAPESEED

2018 ◽  
Author(s):  
Adam KUPCZYK ◽  
Karol TUCKI
Keyword(s):  
Rapeseed Oil ◽  
Spontaneous Combustion ◽  
Combustion Process ◽  
Injection Pressure ◽  
Effect Of Temperature ◽  
High Erucic Acid ◽  
Excess Air ◽  
Pressure Injection ◽  
Auto Ignition ◽  
Basic Parameters

The paper presents results of investigations into diesel engine fuelled with high erucic acid rapeseed oil and its mixture with diesel, petrol and ethanol at different proportions. The study was performed in a chamber with constant volume depending on temperature and air pressure and the coefficient of excess air. The main purpose of performed tests was to determine the effect of various parameters on processes of spontaneous combustion and combustion of fuels. During the study basic parameters of combustion, e.g. auto-ignition delay, greatest pressure and contractual time were compared. Studies show that increased pressure injection improves combustion process for all test fuels, and injection pressure most strongly affect the combustion process of rapeseed oil and its mixtures with ethanol.

Development of a Numerical Model for Ignition Phenomena in a Micro Pilot Ignited Dual Fuel Engine With External Mixture Formation

2017 ◽  
Author(s):  
Michael Schiffner ◽  
Marcus Grochowina ◽  
Thomas Sattelmayer
Keyword(s):  
Flame Propagation ◽  
Ignition Delay ◽  
Cfd Simulation ◽  
Injection Pressure ◽  
Optical Measurements ◽  
Effect Of Temperature ◽  
Dual Fuel ◽  
Ignition Process ◽  
Fuel Blend ◽  
Auto Ignition

In this paper, a numerical investigation of the ignition process of dual fuel engines is presented. Optical measurements revealed that a homogeneous natural gas charge ignited by a small diesel pilot comprises the combustion phenomena of compression ignition of the pilot fuel as well as premixed flame propagation. The 3-Zones Extended Coherent Flame Model (ECFM3Z) was selected, since it can treat auto-ignition, pre-mixed flame propagation and diffusion flame aspects. Usually combustion models in multi-dimensional computational fluid dynamics (CFD) software packages are designed to handle only one reactive species representing the fuel concentration. In the context of the ECFM3Z model the concept of a multi-component fuel is applied to dual fuel operation. Since the available ignition models were not able to accurately describe the ignition characteristics of the investigated setup, a new dual fuel auto-ignition model was developed. Ignition delay times of the fuel blend are tabulated using a detailed reaction mechanism for n-heptane. Thereby, the local progress of pre-ignition reactions in the CFD simulation can be calculated. The ignition model is validated against experiments conducted with a periodically chargeable constant volume combustion chamber. The proposed model is capable to reproduce the ignition delay as well as the location of the flame kernels. The CFD simulations show the effect of temperature stratification and variations in the injection pressure on the apparent ignition delay of the micro pilot.

Pressure Injection Influence on the Combustion Process

2014 ◽  
Vol 659 ◽  
pp. 450-455 ◽  
Author(s):  
Adrian Sabau
Keyword(s):  
Chemical Reaction ◽  
Arrhenius Equation ◽  
Computational Simulation ◽  
Combustion Process ◽  
Injection Pressure ◽  
Combustible Mixture ◽  
Experimental Result ◽  
Mixture Formation ◽  
Pressure Injection ◽  
Di Diesel Engine

Computational simulation for the combustion process in a DI diesel engine was performed through a code made by the author [1]. Two conditions of different injection pressure were examined in the simulation. The injection pressures are 150 MPa and 500 MPa. The combustion phenomenon was modeled as a combined process of formation of a combustible mixture and a chemical reaction. The rate of mixture formation was assumed to be dependent on the turbulence characteristics and the concentration of species in each computational cell. The rate of chemical reaction is described as an Arrhenius equation. The result agrees with the experimental result qualitatively, and the effect of injection pressure on the combustion process is well predicted.

scholarly journals Comparative study of combustion and emissions of diesel engine fuelled with FAME and HVO

2021 ◽  
Author(s):  
Jacek Hunicz ◽  
Paweł Krzaczek ◽  
Michał Gęca ◽  
Arkadiusz Rybak ◽  
Maciej Mikulski
Keyword(s):  
Fuel Injection ◽  
Methyl Esters ◽  
Cetane Number ◽  
Combustion Process ◽  
Injection Pressure ◽  
Common Rail System ◽  
Compression Ignition Engine ◽  
Auto Ignition ◽  
Lower Viscosity ◽  
Cylinder Compression

This study investigates combustion and emission characteristics of a contemporary single-cylinder compression ignition engine fuelled with diesel, fatty acid methyl esters (FAME) and hydrotreated vegetable oil (HVO). These two drop-in fuels have an increasing share in automotive supply chains, yet have substantially different physical and auto-ignition properties. HVO has a lower viscosity and higher cetane number, and FAME has contrary characteristics. These parameters heavily affect mixture formation and the following combustion process, causing that the engine pre-optimized to one fuel option can provide deteriorated performance and excess emissions if another sustainable option is applied. To investigate the scale of this problem, injection pressure sweeps were performed around the stock, low NOX and low PM engine calibration utilizing split fuel injection. The results showed that FAME and HVO prefer lower injection pressures than diesel fuel, with the benefits of simultaneous reduction of all emission indicators compared to DF. Additionally, reduction of injection pressure from 80 MPa to 60 MPa for biodiesels at low engine load resulted in improved brake thermal efficiency by 1 percentage point, due to reduced parasitic losses in the common rail system.

Review of the Investigation of Fuel-Air Premixing and Combustion Process Using Rapid Compression Machine and Direct Visualization System

2013 ◽  
Vol 465-466 ◽  
pp. 265-269 ◽  
Author(s):  
Mohamad Jaat ◽  
Amir Khalid ◽  
Bukhari Manshoor ◽  
Siti Mariam Basharie ◽  
Him Ramsy
Keyword(s):  
High Speed ◽  
Combustion Engine ◽  
Early Stage ◽  
Combustion Process ◽  
Injection Pressure ◽  
Rapid Compression Machine ◽  
Mixture Formation ◽  
Visualization System ◽  
Optical Visualization ◽  
Rapid Compression

s :This paper reviews of some applications of optical visualization system to compute the fuel-air mixing process during early stage of mixture formation and late injection in Diesel Combustion Engine. This review has shown that the mixture formation is controlled by the characteristics of the injection systems, the nature of the air swirl and turbulence in thecylinder, and spray characteristics. Few experimental works have been investigated and found that the effects of injection pressure and swirl ratio have a great effect on the mixture formation then affects to the flame development and combustion characteristics.This paper presents the significance of spray and combustion study with optical techniques access rapid compression machine that have been reported by previous researchers. Experimental results are presentedin order to provide in depth knowledge as assistance to readers interested in this research area. Analysis of flame motion and flame intensity in the combustion chamber was performed using high speed direct photographs and image analysis technique. The application of these methods to the investigation of diesel sprays highlights mechanisms which provide a better understanding of spray and combustion characteristics.

Study on the Oxidation and Spontaneous Combustion Characteristics of Jurassic Coal in North Shaanxi

2014 ◽  
Vol 977 ◽  
pp. 124-128 ◽  
Author(s):  
Jun Deng ◽  
Kai Wang ◽  
Xiao Wei Zhai
Keyword(s):  
Functional Groups ◽  
Spontaneous Combustion ◽  
Combustion Process ◽  
Amorphous Structure ◽  
X Ray Diffraction ◽  
High Oxygen Content ◽  
Ether Oxygen ◽  
Jurassic Coal ◽  
Proximate And Ultimate Analysis ◽  
Low Sulfur

Proximate and ultimate analysis, X-ray diffraction, infrared spectroscopy and thermal analysis experiments were carried out to study the spontaneous combustion oxidation based characteristic of six Jurassic coal samples from North Shaanxi in West China and three Permo-carboniferous coal samples from East China. The results showed that the characteristic of north Shaanxi Jurassic coal was low ash, low sulfur, high volatile, high oxygen content and amorphous structure. More type and quantity of reactive functional groups existed in the original Jurassic coal, such as carboxyl, methyl, methylene and ether oxygen. And the characteristic temperatures of north Shaanxi Jurassic coal sample in the oxidation and spontaneous combustion process was lower than other coal samples, due to the participation in the reaction with oxygen of the more active functional groups.

Numerical Simulation on Moisture Influence to MSW Combustion

2014 ◽  
Vol 1006-1007 ◽  
pp. 181-184
Author(s):  
Zhu Sen Yang ◽  
Xing Hua Liu ◽  
Shu Chen
Keyword(s):  
Numerical Simulation ◽  
Moisture Content ◽  
Flue Gas ◽  
Combustion Process ◽  
Average Temperature ◽  
Excess Air ◽  
Heat Value ◽  
Moisture Influence ◽  
Excess Air Coefficient ◽  
Combustible Gases

The combustion process of municipal solid waste (MSW) in a operating 750t/d grate furnace in Guangzhou was researched by means of numerical simulation. The influence of MSW moisture content on burning effect was discussed. The results show that: with the moisture content dropped from 50% to 30%, the heat value could be evaluated from 13.72% to 54.91% and the average temperature in the furnace could be promoted 90-248°C. However, the combustible gases and particle in the flue gas of outlet would take up a high proportion since lacking of oxygen would lead to an incomplete combustion. The excess air coefficient should be increased to 2.043~2.593 in order to ensure the flue gas residence time more than 2s and temperature in the furnace higher to 800°C.

scholarly journals Study on the Microscopic Mechanism of Spontaneous Combustion and Oxidation Kinetics of Water-Leached Coal

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Naifu Cao ◽  
Gang Wang ◽  
Yuntao Liang
Keyword(s):  
Kinetic Model ◽  
Moisture Content ◽  
Spontaneous Combustion ◽  
Water Immersion ◽  
Combustion Process ◽  
Oxidation Kinetic ◽  
Oxidation Mechanism ◽  
Temperature Oxidation ◽  
Before And After ◽  
Spontaneous Combustion Of Coal

In this article, a series of experiments have been carried out to study the spontaneous combustion and oxidation mechanism of coal after water immersion and investigate its tendency to spontaneous combustion, analyze the difficulty of spontaneous combustion of coal samples under different water immersion conditions, and establish a kinetic model of water immersion coal oxidation (taking the Bulianta 12# coal as a case study). They rely on physical oxidation adsorption, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetry, and oil bath heating. SEM has been used to analyze the characteristics of coal pore structure under different water immersion conditions (water-saturated coal samples under different water loss conditions until the coal samples are completely dried); FTIR served to investigate the characteristics of the molecular chemical structure of the coal surface before and after the coal is immersed in water. Through programmed temperature oxidation experiments combined with FTIR analyses and gas chromatographic (GC) analysis of gaseous products, it has been possible to study the changes of molecular structure and gas products on the surface of coal samples at different temperatures and water immersion conditions. The oxidation reaction rate of the 12# coal samples of Shendong Mine’s Bulianta Mine under different water content conditions during the spontaneous combustion process has been quantitatively studied. The difficulty of spontaneous combustion of coal samples has been correspondingly addressed. A kinetic model from the perspective of oxygen consumption has been proposed. Thermogravimetry-differential scanning calorimetry (TG-DSC) has been used to analyze and study the exothermal oxidation process before and after coal immersion. From the perspective of the exothermic intensity of the coal-oxygen reaction, an oxidation kinetic model for immersed coal samples has been developed to qualitatively determine its spontaneous combustion tendency. Results have shown that the increase in the specific surface area increases the risk of spontaneous combustion, and coal samples after soaking and drying have a stronger tendency to spontaneous combustion than raw coal. The moisture content of the coal sample leading to the easiest ignition conditions is 16.05%. Regardless of the moisture content, the critical temperature is maintained at 65–75°C, and the temperature of the left coal in the goaf should be prevented from exceeding this critical value.

scholarly journals Effects of organic sulfur on oxidation spontaneous combustion characteristics of coking coal

2021 ◽  
pp. 014459872110490
Author(s):  
Fei Gao ◽  
Zhe Jia ◽  
Mei-ling Qin ◽  
Xiao-gang Mu ◽  
Yi-fei Teng ◽  
...  
Keyword(s):  
Sulfur Content ◽  
Photoelectron Spectroscopy ◽  
Spontaneous Combustion ◽  
Characteristic Temperature ◽  
Combustion Process ◽  
Oxidation Products ◽  
Organic Sulfur ◽  
Scanning Calorimetry ◽  
Clean Coal ◽  
Spontaneous Combustion Of Coal

Research on the spontaneous combustion of coal caused by sulfur has always been focused on pyrite in coal but has rarely considered the influence of organic sulfur. In this paper, coal samples, rather than model compounds, were used to study the influence of organic sulfur content in coal on its spontaneous combustion process. The results of X-ray photoelectron spectroscopy and thermogravimetry, differential scanning calorimetry, and mass spectrometry indicate that organic sulfur in Shuiyu clean coal exists in forms of mercaptan, thioether, sulfone (sulfoxide), and thiophene. With the decrease of organic sulfur content, the characteristic temperature points and the peak values of the exothermic curves in the process of coal oxidation spontaneous combustion all shifted toward higher temperatures. The ignition activation energy of coal also increased, and the initial and peak gas evolution temperatures of the oxidation products shifted toward higher temperatures. These findings suggest that the reduction of organic sulfur content can inhibit the oxidation process and spontaneous combustion tendency of coal. This effectively reveals the mechanism of the spontaneous combustion of coal and is of great significance to future studies in this field.

scholarly journals Chemiluminescence analysis of the effect of butanol-diesel fuel blends on the spray-combustion process in an experimental common rail diesel engine

2015 ◽  
Vol 19 (6) ◽  
pp. 1943-1957
Author(s):  
Simona Merola ◽  
Luca Marchitto ◽  
Cinzia Tornatore ◽  
Gerardo Valentino
Keyword(s):  
Diesel Fuel ◽  
Flame Temperature ◽  
Combustion Process ◽  
Injection Pressure ◽  
Common Rail ◽  
Pilot Injection ◽  
Soot Emission ◽  
Compression Ignition Engine ◽  
Working Cycle ◽  
Main Injection

Combustion process was studied from the injection until the late combustion phase in an high swirl optically accessible combustion bowl connected to a single cylinder 2-stroke high pressure common rail compression ignition engine. Commercial diesel and blends of diesel and n-butanol (20%: BU20 and 40%: BU40) were used for the experiments. A pilot plus main injection strategy was investigated fixing the injection pressure and fuel mass injected per stroke. Two main injection timings and different pilot-main dwell times were explored achieving for any strategy a mixing controlled combustion. Advancing the main injection start, an increase in net engine working cycle (>40%) together with a strong smoke number decrease (>80%) and NOx concentration increase (@50%) were measured for all pilot injection timings. Compared to diesel fuel, butanol induced a decrease in soot emission and an increase in net engine working area when butanol ratio increased in the blend. A noticeable increase in NOx was detected at the exhaust for BU40 with a slight effect of the dwell-time. Spectroscopic investigations confirmed the delayed auto-ignition (~60 ms) of the pilot injection for BU40 compared to diesel. The spectral features for the different fuels were comparable at the start of combustion process, but they evolved in different ways. Broadband signal caused by soot emission, was lower for BU40 than diesel. Different balance of the bands at 309 and 282 nm, due to different OH transitions, were detected between the two fuels. The ratio of these intensities was used to follow flame temperature evolution.

Fuel Injection Control for a Valve Array in a Shockless Explosion Combustor

2018 ◽  
Author(s):  
Jan-Simon Schäpel ◽  
Rudibert King ◽  
Fatma Yücel ◽  
Fabian Völzke ◽  
Christian Oliver Paschereit ◽  
...  
Keyword(s):  
Fuel Injection ◽  
Combustion Process ◽  
Firing Frequency ◽  
Mixed Integer ◽  
Test Rig ◽  
Proportional Valve ◽  
Control Approach ◽  
Fuel Stratification ◽  
Auto Ignition ◽  
Filling Time

Approximate constant volume combustion (aCVC) is a promising way to optimize the combustion process in a gas turbine, which would exceed the gain in efficiency resulting from optimizing other components significantly. This work deals with a recently proposed approach: shockless explosion combustion (SEC). Compared to already known concepts, such as pulsed detonation combustion (PDC), it overcomes several disadvantages, e.g., sharp pressure transitions and entropy generation due to shock waves. For an SEC, accurate fuel stratification is required to achieve a quasi-homogeneous auto-ignition. In an atmospheric test rig quasi-homogeneous ignitions were achieved previously in non-resonant operation. To achieve a resonant operation, which goes along with a higher firing frequency, lower ignition and injection times are required. For this purpose, an array of solenoid valves was designed to allow for highly dynamic operation within short filling time spans. Using a novel mixed-integer control approach, these solenoid valves were actuated such that a desired fuel profile was generated. In this paper, the mentioned test rig was used for non-reacting fuel measurements to compare the quality of the axial fuel stratification achieved by using the valve array with the one achieved by using a slower proportional valve. In the experimental investigation the actuation with the valve array proved to adjust the required fuel stratification with the same quality as the actuation with the proportional valve, which was already successfully applied to the reactive set-up. Hence, the mixed-integer controlled valve array is considered a useful concept for upcoming resonant reactive SEC investigations.

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