scholarly journals Characteristics of Ammonia/Hydrogen Premixed Combustion in a Novel Linear Engine Generator

Proceedings ◽  
2020 ◽  
Vol 58 (1) ◽  
pp. 2
Author(s):  
Fangyu Zhang ◽  
Gen Chen ◽  
Dawei Wu ◽  
Tie Li ◽  
Zhifei Zhang ◽  
...  
Keyword(s):  
Ignition Delay ◽  
Equivalence Ratio ◽  
Initial Temperature ◽  
Laminar Flame ◽  
Initial Pressure ◽  
Premixed Combustion ◽  
Combustion Mechanism ◽  
Detailed Chemical Kinetics ◽  
Linear Engine ◽  
Premixed Laminar

In order to support the development of a novel linear engine generator (LEG), the characteristics of ammonia/hydrogen premixed combustion are studied by using a detailed chemical kinetics mechanism. The ammonia combustion mechanism is identified among several mechanisms and validated with published experimental data. A parametric analysis is carried out under LEG typical working conditions to study the effects of equivalence ratio (0.80 – 1.60), hydrogen blending ratio (0.0 – 0.6), initial temperature (300 – 700 K) and initial pressure (1 – 20 bar) on premixed laminar flame speed, ignition delay and key flame species concentrations. It is shown that an equivalence ratio of around 1.10 – 1.20 is beneficial to both ammonia flame stability and lower NOx emission. Ignition delay is reduced with the increase in hydrogen blending ratio, initial temperature and initial pressure. At a certain initial temperature and initial pressure, the effects of hydrogen blending ratio can be negligible for over 50% hydrogen in the fuel. Under higher pressure (>10 bar), the initial pressure has a minor influence on the ignition delay reduction. It is also found that the high-pressure high-temperature environment contributes to reducing NO emission considerably in ammonia/hydrogen combustion, which implies the potential of a low NOx LEG fuelled by ammonia/hydrogen.

scholarly journals PENENTUAN ANGKA OKTANA BAHAN BAKAR KOMERSIAL DENGAN MENGGUNAKAN MODEL KINETIKA OKSIDASI DAN PEMBAKARAN HIDROKARBON MULTIKOMPONEN

REAKTOR ◽  
2012 ◽  
Vol 14 (2) ◽  
pp. 109 ◽  
Author(s):  
Yuswan Muharam ◽  
Chandra Hadiwijaya ◽  
Jacquin Suryadi
Keyword(s):  
Old Age ◽  
Ignition Delay ◽  
Equivalence Ratio ◽  
Initial Pressure ◽  
Volume Percentage ◽  
Ignition Delay Times ◽  
Delay Times ◽  
Commercial Fuel ◽  
Good Agreement

One of the characteristics of gasoline fuel is anti-knock property represented by its octanenumber. The determination of octane numbers in Indonesia is by using cooperative fuel researchengines. The usage of cooperative fuel research engines in Indonesia has constraints, i.e. the limitednumber of the units and the old age. This study aims to obtain the octane numbers of commercialfuels by using kinetic models. The kinetics models of the oxidation and combustion of primaryreference fuel and multi component hydrocarbons are used to calculate the ignition delay times ofprimary reference fuel and commercial fuels, respectively. The ignition delay times of primaryreference fuel and commercial fuels are calculated at the same initial pressure and temperature, aswell as the same equivalence ratio. The octane number of a commercial fuel is known if its ignitiondelay time agrees with that of PFR possessing a certain volume percentage of isooctane. The modelgenerates the octane numbers of commercial fuels BB-A being 92.5, BB-B being 94.5, BB-C being89, BB-D being 90.5 and BB-E being 91.5 with the good agreement with those claimed by the fuelproducers. Salah satu karakteristik bahan bakar bensin adalah sifat anti ketukan yang dinyatakan dengan angkaoktana. Penentuan angka oktana di Indonesia menggunakan mesin CFR (cooperative fuel research).Pemakaian mesin CFR di Indonesia memiliki kendala, yaitu jumlah unit terbatas dan usia tua.Penelitian ini bertujuan mendapatkan angka oktana bahan bakar komersial dengan menggunakanmodel kinetika. Model kinetika oksidasi dan pembakaran bahan bakar rujukan utama dan modelhidrokarbon multikomponen yang telah divalidasi masing-masing digunakan untuk menghitungwaktu tunda ignisi bahan bakar rujukan utama dan bahan bakar komersial. Waktu tunda ignisibahan bakar rujukan utama dan bahan bakar komersial dihitung pada tekanan dan temperatur awal,serta rasio ekuivalensi yang sama. Angka oktana suatu bahan bakar komersial diketahui apabilawaktu tunda ignisinya cocok dengan waktu tunda ignisi bahan bakar rujukan utama yang memilikipersen volume isooktana tertentu. Model menghasilkan angka oktana bahan bakar komersial BB-Asebesar 92,5, BB-B 94,5, BB-C 89, BB-D 90,5 dan BB-E 91,5 yang memiliki ketepatan yang tinggiterhadap klaim produser bahan bakar komersial.

scholarly journals The adiabatic flame temperature and laminar flame speed of methane premixed flames at varying pressures

2019 ◽  
pp. 220-227
Author(s):  
Ahmad Sakhrieh
Keyword(s):  
Equivalence Ratio ◽  
Initial Temperature ◽  
Laminar Flame ◽  
Flame Temperature ◽  
Flame Speed ◽  
Pressure Increase ◽  
Stoichiometric Ratio ◽  
Laminar Flame Speed ◽  
Adiabatic Flame Temperature ◽  
Percent Increase

This paper studies the influence of equivalence ratio, pressure and initial temperature on adiabatic flame temperature and laminar flame speed of methane-air mixture. The results indicate that adiabatic flame temperature is weakly correlated with pressure. The adiabatic flame temperature increases only by about 50?C as a result of 30 bar pressure increase. The flame speed is inversely proportional to pressure. The maximum adiabatic flame temperature and flame speed occur at the stoichiometric ratio, ?=1. The percent increase in the flame speed was about 400% when the initial temperature of the mixture is increased from 25?C to 425?C.

scholarly journals Investigation on effect of equivalence ratio and engine speed on homogeneous charge compression ignition combustion using chemistry based CFD code

2014 ◽  
Vol 18 (1) ◽  
pp. 89-96 ◽  
Author(s):  
Jafar Ghafouri ◽  
Sina Shafee ◽  
Amin Maghbouli
Keyword(s):  
Natural Gas ◽  
Equivalence Ratio ◽  
Engine Speed ◽  
Homogeneous Charge Compression Ignition ◽  
Initial Pressure ◽  
Methane Combustion ◽  
Operating Conditions ◽  
Compression Ignition ◽  
Detailed Chemical Kinetics ◽  
Homogeneous Charge

Combustion in a large-bore natural gas fuelled diesel engine operating under Homogeneous Charge Compression Ignition mode at various operating conditions is investigated in the present paper. Computational Fluid Dynamics model with integrated chemistry solver is utilized and methane is used as surrogate of natural gas fuel. Detailed chemical kinetics mechanism is used for simulation of methane combustion. The model results are validated using experimental data by Aceves, et al. (2000), conducted on the single cylinder Volvo TD100 engine operating at Homogeneous Charge Compression Ignition conditions. After verification of model predictions using in-cylinder pressure histories, the effect of varying equivalence ratio and engine speed on combustion parameters of the engine is studied. Results indicate that increasing engine speed provides shorter time for combustion at the same equivalence ratio such that at higher engine speeds, with constant equivalence ratio, combustion misfires. At lower engine speed, ignition delay is shortened and combustion advances. It was observed that increasing the equivalence ratio retards the combustion due to compressive heating effect in one of the test cases at lower initial pressure. Peak pressure magnitude is increased at higher equivalence ratios due to higher energy input.

scholarly journals Premixed Combustion of Coconut Oil on Perforated Burner

2013 ◽  
Vol 2 (3) ◽  
pp. 133-139
Author(s):  
I.K.G. Wirawan ◽  
I.N.G. Wardana ◽  
Rudy Soenoko ◽  
Slamet Wahyudi
Keyword(s):  
Equivalence Ratio ◽  
Laminar Flame ◽  
Burning Velocity ◽  
Perforated Plate ◽  
Coconut Oil ◽  
Ambient Air ◽  
Premixed Combustion ◽  
Flame Velocity ◽  
Bunsen Flame ◽  
Rich Mixture

Coconut oil premixed combustion behavior has been studied experimentally on perforated burner with equivalence ratio (φ) varied from very lean until very rich. The results showed that burning of glycerol needs large number of air so that the laminar burning velocity (SL) is the highest at very lean mixture and the flame is in the form of individual Bunsen flame on each of the perforated plate hole. As φ is increased the  SL decreases and the secondary Bunsen flame with open tip occurs from φ =0.54 at the downstream of perforated flame. The perforated flame disappears at φ = 0.66 while the secondary Bunsen flame still exist with SL increases following that of hexadecane flame trend and then extinct when the equivalence ratio reaches one or more. Surrounding ambient air intervention makes SL decreases, shifts lower flammability limit into richer mixture, and performs triple and cellular flames. The glycerol diffusion flame radiation burned fatty acids that perform cellular islands on perforated hole.  Without glycerol, laminar flame velocity becomes higher and more stable as perforated flame at higher φ. At rich mixture the Bunsen flame becomes unstable and performs petal cellular around the cone flame front. Keywords: cellular flame; glycerol; perforated flame;secondary Bunsen flame with open tip; triple flame

scholarly journals RESEARCH INTO THREE‐COMPONENT BIODIESEL FUELS COMBUSTION PROCESS USING A SINGLE DROPLET TECHNIQUE

Transport ◽  
2007 ◽  
Vol 22 (4) ◽  
pp. 312-315 ◽  
Author(s):  
Laurencas Raslavičius ◽  
Donatas Markšaitis
Keyword(s):  
Ignition Delay ◽  
Fuel Injection ◽  
Burning Velocity ◽  
Combustion Process ◽  
Combustion Mechanism ◽  
Physical Parameters ◽  
Detailed Chemical Kinetics ◽  
Biodiesel Fuels ◽  
Engine Emission ◽  
Physical And Chemical

In order to reduce the engine emission while at same time improving engine efficiency, it is very important to clarify the combustion mechanism. Even if, there are many researches into investigating the mechanism of engine combustion, so that to clarify the relationship between complicated phenomena, it is very difficult to investigate due to the complicated process of both physical and chemical reaction from the start of fuel injection to the end of combustion event. The numerical simulations are based on a detailed vaporization model and detailed chemical kinetics. The influence of different physical parameters like droplet temperature, gas phase temperature, ambient gas pressure and droplet burning velocity on the ignition delay process is investigated using fuel droplet combustion stand. Experimental results about their influence on ignition delay time were presented.

Laminar Flame Speeds of Oxy-Methane Flames With CO2 Dilution at Elevated Pressures

2020 ◽  
Author(s):  
Mattias A. Turner ◽  
Waruna D. Kulatilaka ◽  
Eric L. Petersen
Keyword(s):  
Experimental Data ◽  
Initial Temperature ◽  
Laminar Flame ◽  
Full Range ◽  
Initial Pressure ◽  
Lewis Number ◽  
Flame Speed ◽  
Schlieren Imaging ◽  
Elevated Pressures ◽  
Test Conditions

Abstract Spherically expanding, laminar flame experiments have been conducted for oxy-methane mixtures diluted in CO2. Test conditions consisted of pressures of 5 atm and 10 atm, an ambient initial temperature of 298 K, and a full range of equivalence ratios from lean to rich. Schlieren imaging was used to image the flames. The mixtures tested in this study contained helium for the purpose of increasing the Lewis number to suppress onset of thermal-diffusive instabilities. Flame speeds ranged from 24.3 to 30.4 cm/s at 5 atm initial pressure and from 17.9 to 22.6 cm/s at 10 atm, resulting in an approximately 26% decrease in flame speed across all tested equivalence ratios as a result of the doubling in initial pressure. Predicted flame speeds from AramcoMech2.0 tended to be higher than the experimental data by 3% at 5 atm initial pressure and 8% at 10 atm initial pressure, indicating that the performance of the mechanism is quite good for this mixture, but diminishes slightly as pressure increases.

Estimating Laminar Flame Speed and Ignition Delay for a Series of Natural Gas Mixtures at IC Engine-Relevant Conditions

2019 ◽  
Vol 142 (6) ◽  
Author(s):  
Kelsey Fieseler ◽  
Taylor Linker ◽  
Mark Patterson ◽  
Daniel Rem ◽  
Timothy J. Jacobs
Keyword(s):  
Natural Gas ◽  
Ignition Delay ◽  
Laminar Flame ◽  
Initial Conditions ◽  
Initial Pressure ◽  
Fuel Mixture ◽  
Flame Speed ◽  
Laminar Flame Speed ◽  
Ic Engine ◽  
The Impact

Abstract Two equations are developed to estimate laminar flame speed and ignition delay for different alkane mixtures at a range of engine-relevant conditions. Fuel mixtures of methane, ethane, propane, butane, and pentane were selected by analyzing the natural gas composition in a natural gas pipeline located in the Midwestern United States. The laminar flame speed and ignition delay were calculated for each mixture at each set of conditions using Cantera, a chemical kinetics solver. The range of initial conditions for laminar flame speed includes temperatures from 300 to 700 K, pressures from 1 to 40 bar, equivalence ratios from 0.4 to 1.2, and residual fractions from 0% to 20%. These data were then fit to a non-linear regression. The range of initial conditions for the ignition delay equation includes temperatures from 1100 to 2000 K, pressures from 1 to 40 bar, equivalence ratios from 0.4 to 1.15, and residual fractions from 0% to 20%. These data were fit to a previously developed equation. Sensitivity studies were conducted on each equation to quantify the impact of the independent variables on the target variable. This showed that, for laminar flame speed, the initial pressure, temperature, and equivalence ratio had the largest impact, with fuel composition having a lesser impact. For ignition delay, the temperature and pressure were shown to have the largest impact. There is a room for improvement, namely, increasing the fuel mixture variability and range of initial conditions, and developing a better fit to the data.

Development of a New Skeletal Chemical Kinetic Mechanism for Ethanol Reference Fuel

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
O. Samimi Abianeh
Keyword(s):  
Ignition Delay ◽  
Laminar Flame ◽  
Kinetic Mechanism ◽  
Chemical Kinetic ◽  
Flame Speed ◽  
Combustion Mechanism ◽  
Laminar Flame Speed ◽  
Surrogate Fuels ◽  
Chemical Kinetic Mechanism ◽  
Fuel Surrogates

A new skeletal chemical kinetic mechanism of ethanol reference fuel (including ethanol, iso-octane, n-heptane, and toluene combustion mechanisms) consisting of 62 species and 194 reactions is developed for oxidation and combustion of gasoline blend surrogate fuels. The skeletal ethanol chemical kinetic mechanism is added to the toluene reference fuel (TRF) mechanism (including iso-octane, n-heptane, and toluene combustion mechanisms) using reaction paths and semidecoupling model. The ignition delay and laminar flame speed of the new combustion mechanism were modeled by using several fuel surrogates at different pressures, temperatures, and equivalence ratios. The skeletal chemical kinetic mechanism ignition delay and laminar flame speed are validated by comparison to the available experimental data of the shock tube and plate burner. The results indicate that satisfactory agreement between predictions and experimental measurements are achieved.

scholarly journals The Temperature and Pressure Dependencies of Propagation Characteris-tics for Premixed Laminar Ethanol-Air Flames

2012 ◽  
Vol 6 (1) ◽  
pp. 55-64 ◽  
Author(s):  
S. Y. Liao ◽  
D. L. Zhong ◽  
C. Yang ◽  
X. B. Pan ◽  
C. Yuan ◽  
...  
Keyword(s):  
Equivalence Ratio ◽  
Initial Temperature ◽  
Burning Velocity ◽  
Initial Mixture ◽  
Spark Ignition ◽  
Laminar Burning Velocity ◽  
Propagation Characteristics ◽  
Activation Temperature ◽  
Temperature And Pressure ◽  
Premixed Laminar

Laminar burning velocity is strongly dependent on mixture characteristics, e.g. initial temperature, pressure and equivalence ratio. In this work, spherically expanding laminar premixed flames, freely propagating from a spark ignition source in initially quiescent ethanol-air mixtures, have been imaged and then the laminar burning velocities were obtained at initial temperatures of 358 K to 500K, pressure of 0.1 to 0.2 MPa and equivalence ratio of 0.7 to 1.4. The measured re-sults and literature data on ethanol laminar burning velocities were accumulated, to analyze the effects of initial tempera-ture and pressure on the propagation characteristics of laminar ethanol-air flames. A correlation in the form of ul=ulo(Tu/Tu0)αT (Pu/Pu0)βP , and validated over much wide temperature, pressure and equivalence ratio ranges. The global activation temperatures were determined in terms of the laminar burning mass flux for ethanol-air flames. And the Zel’dovich numbers were estimated as well. The dependencies of global activation temperature and Zel’dovich number on initial mixture pressure, temperature and equivalence ratio were explored. Additionally, an alterna-tive correlation of laminar burning velocities, from the view of theoretical arguments, was proposed on the basis of the de-termined ethanol-air laminar mass burning flux. Good agreements were obtained in its comparison with the literature data.

scholarly journals Experimental Investigation of Flame Speed of Gasoline Fuel-Air Mixture

2018 ◽  
Vol 8 (02) ◽  
Author(s):  
Oras Khudhair Obayes ◽  
Haroun A.K. Shahad
Keyword(s):  
Experimental Investigation ◽  
High Speed ◽  
Equivalence Ratio ◽  
Initial Temperature ◽  
Initial Pressure ◽  
Flame Speed ◽  
Combustion System ◽  
Constant Volume Combustion Chamber ◽  
And Performance ◽  
Experimental Rig

Flame speed is an important aspect of fuel combustion characteristics. It affects combustion system design and performance. In this study, a laboratory experimental rig has been built to investigate the effect of equivalence ratio of gasoline-air mixture in a centrally ignited constant volume combustion chamber on flame speed at an initial pressure of 1bar and an initial temperature of 483 K using high speed flame photography technique. The results of the outwardly expanding spherical flame showed that the flame speed depends on both equivalence ratio and flame radius. It decreases slightly with the increase of flame radius and increases with the equivalence ratio until slightly larger than stiochiometric and then decreases. The flame speed reached 1.45 m/s at Φ= 0.8, (1.6) m/s at Φ= 1 and 1.27 m/s at Φ= 1.5

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