scholarly journals Simulation of the Oxidation and Combustion of Mixed Diesel-Biodiesel Fuel

2018 ◽  
Vol 156 ◽  
pp. 03008
Author(s):  
Yuswan Muharam ◽  
Danny Leonardi ◽  
Alisya P Ramadhania

A comparative simulation-based research has been set up to obtain valid kinetic models of the oxidation and combustion of biodiesel surrogate and diesel surrogate, as well as mixed diesel-biodiesel surrogates which is used to predict their ignition delay times (IDT). The research consists of the development of the detailed kinetic models of the oxidation and combustion of biodiesel surrogate and diesel surrogate, the validation of the two models with the corresponding experimental IDT data, the merging and the validation of the two models for mixed diesel-biodiesel surrogates. The biodiesel surrogate kinetic model was validated with the experimental IDT data of methyl 9-decenoate at 20 atm and three equivalence ratios. The diesel surrogate kinetic model was validated with the experimental IDT data of n-hexadecane at the pressure ranging from 2 atm to 5 atm and the equivalence ratio of 1.0. The diesel-biodiesel surrogate kinetic model was validated with the experimental IDT data of real diesel-biodiesel fuels for four compositions and at 1.18 atm. The validation results of all models show that the models and the experiments are in good agreement.

REAKTOR ◽  
2012 ◽  
Vol 14 (2) ◽  
pp. 109 ◽  
Author(s):  
Yuswan Muharam ◽  
Chandra Hadiwijaya ◽  
Jacquin Suryadi

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.


Author(s):  
P. Gokulakrishnan ◽  
M. S. Klassen ◽  
R. J. Roby

Ignition delay times of a “real” synthetic jet fuel (S8) were measured using an atmospheric pressure flow reactor facility. Experiments were performed between 900 K and 1200 K at equivalence ratios from 0.5 to 1.5. Ignition delay time measurements were also performed with JP8 fuel for comparison. Liquid fuel was prevaporized to gaseous form in a preheated nitrogen environment before mixing with air in the premixing section, located at the entrance to the test section of the flow reactor. The experimental data show shorter ignition delay times for S8 fuel than for JP8 due to the absence of aromatic components in S8 fuel. However, the ignition delay time measurements indicate higher overall activation energy for S8 fuel than for JP8. A detailed surrogate kinetic model for S8 was developed by validating against the ignition delay times obtained in the present work. The chemical composition of S8 used in the experiments consisted of 99.7 vol% paraffins of which approximately 80 vol% was iso-paraffins and 20% n-paraffins. The detailed kinetic mechanism developed in the current work included n-decane and iso-octane as the surrogate components to model ignition characteristics of synthetic jet fuels. The detailed surrogate kinetic model has approximately 700 species and 2000 reactions. This kinetic mechanism represents a five-component surrogate mixture to model generic kerosene-type jets fuels, namely, n-decane (for n-paraffins), iso-octane (for iso-paraffins), n-propylcyclohexane (for naphthenes), n-propylbenzene (for aromatics) and decene (for olefins). The sensitivity of iso-paraffins on jet fuel ignition delay times was investigated using the detailed kinetic model. The amount of iso-paraffins present in the jet fuel has little effect on the ignition delay times in the high temperature oxidation regime. However, the presence of iso-paraffins in synthetic jet fuels can increase the ignition delay times by two orders of magnitude in the negative temperature (NTC) region between 700 K and 900 K, typical gas turbine conditions. This feature can have a favorable impact on preventing flashback caused by the premature autoignition of liquid fuels in lean premixed prevaporized (LPP) combustion systems.


Author(s):  
N. Slavinskaya ◽  
A. Zizin ◽  
M. Braun-Unkhoff ◽  
C. Lenfers

A semi-detailed kinetic mechanism with 100 species and 816 reactions for ethylene combustion including PAH formation was elaborated. The model includes the C2H5OH sub mechanism combustion as well. This mechanism has in view to be the base of further kinetic schemes of practical fuels (reference fuels). The mechanism was reduced to a skeletal model with 72 species and 580 reactions. The elaborated models were validated on experimental data bases of heat release as well as formation of polyaromatic hydrocarbons and soot in laminar premixed C2H4, C2H4 / C2H5OH flames taken from literature. The calculated ignition delay times, laminar flame speeds, as well as temporal profiles of small and large aromatics and also soot particles are in good agreement with experimental data obtained for pressures 1 – 5 bar, temperatures T0 = 1100 – 2300 K, fuel/oxygen equivalence ratio φ = 0.5 – 2.


2015 ◽  
Vol 29 (7) ◽  
pp. 4557-4566 ◽  
Author(s):  
Erjiang Hu ◽  
Yizhen Chen ◽  
Zihang Zhang ◽  
Xiaotian Li ◽  
Yu Cheng ◽  
...  

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Ghassan Nicolas ◽  
Mohammad Janbozorgi ◽  
Hameed Metghalchi

Rate-controlled constrained-equilibrium method has been further developed to model methane/air combustion. A set of constraints has been identified to predict the nonequilibrium evolution of the combustion process. The set predicts the ignition delay times of the corresponding detailed kinetic model to within 10% of accuracy over a wide range of initial temperatures (900 K–1200 K), initial pressures (1 atm–50 atm) and equivalence ratios (0.6–1.2). It also predicts the experimental shock tube ignition delay times favorably well. Direct integration of the rate equations for the constraint potentials has been employed. Once the values of the potentials are obtained, the concentration of all species can be calculated. The underlying detailed kinetic model involves 352 reactions among 60 H/O/N/C1-2 species, hence 60 rate equations, while the RCCE calculations involve 16 total constraints, thus 16 total rate equations. Nonetheless, the constrained-equilibrium concentrations of all 60 species are calculated at any time step subject to the 16 constraints.


Author(s):  
A. F. Khan ◽  
A. A. Burluka

Diverse kinetic models for iso-octane, n-heptane, toluene and ethanol i.e. main gasoline surrogates, have been investigated. The models have different levels of complexity and strong and weak points. Firstly, ignition delay times for various fuel blends have been calculated and compared with published shock tube measurements. Kinetic models which are capable of distinguishing between Primary and Toluene Reference Fuels have been used further on in a zero-dimensional Homogeneous Charge Compression Ignition engine model to predict auto-ignition. The modelling results have been compared to the experimental results obtained in a single cylinder research engine. A discussion has been made on the ability of these models to predict autoignition.


Author(s):  
Eric L. Petersen ◽  
Joel M. Hall ◽  
Danielle M. Kalitan ◽  
Matthew J. A. Rickard

Recent results from experiments and modeling by the authors are reviewed for the ignition of acetylene, ethylene, and ethane in oxygen/argon mixtures at temperatures between 1000 and 2300 K and pressures near 1 atm. The ignition measurements were obtained behind reflected shock waves using emission from electronically excited OH and CH radicals to monitor the reaction progress. While many discrepancies exist amongst previous studies for these lower-order hydrocarbons, the accuracy afforded by the present experiments provides conclusive evidence verifying the trends seen in certain studies from the literature. Several modern, detailed chemical kinetics mechanisms were compared to the new results with some models showing quite good agreement with both ignition delay times and species profiles, particularly for stoichiometric mixtures. However, improvement is still required to match the entire range of fuel concentrations, temperatures, and mixture ratios, particularly for fuel-rich mixtures.


Author(s):  
Xuan Zheng ◽  
Shirin Jouzdani ◽  
Benjamin Akih-Kumgeh

Abstract Methane (CH4) and bio alcohols have different ignition properties. These have been extensively studied and the resulting experimental data have been used to validate chemical kinetic models. Methane is the main component of natural gas, which is of interest because of its relative availability and lower emissions compared to other hydrocarbon fuels. Given growing interest in fuel-flexible systems, there can be situations in which the combustion properties of natural gas need to be modified by adding biofuels such as bio alcohols. This can occur in dual-fuel internal combustion engines or gas turbines with dual-fuel capabilities. The combustion behavior of such blends can be understood by studying the auto ignition properties in fundamental combustion experiments. Studies of the ignition of such blends are very limited in the literature. In this work, the auto ignition of methane and bio alcohol fuel blends is investigated using a shock tube facility. The chosen bio alcohols are ethanol (C2H5OH) and n-propanol (NC3H7OH). Experiments are carried out at 3 atm and 10 atm for stoichiometric and lean mixtures of fuel, oxygen, and argon. The ignition delay times of the pure fuels are first established at conditions of constant oxygen concentration and comparable pressures. The ignition delay times of blends with 50% methane are then measured. The pyrolysis kinetics of the blends is further explored by measuring CO formation during pyrolysis of the alcohol and methane–alcohol blends. The resulting experimental data are compared with the predictions of selected chemical kinetic models to establish the ability of these models to predict the disproportionate enhancement of methane ignition by the added alcohol.


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