Test Location Effects on Ignition Delay Times in Shock Tubes

2022 ◽  
Author(s):  
Juan Cruz Pellegrini ◽  
Justin J. Urso ◽  
Cory Kinney ◽  
Andrew Laich ◽  
Michael Pierro ◽  
...  
2018 ◽  
Vol 5 (1) ◽  
pp. 392
Author(s):  
Yuswan Muharam

There is continued interest in developing a better understanding of the oxidation and combustion of large hydrocarbons, which are good representative for practical fuels used in automotive engines for a wide range of operating conditions. This interest is motivated by the need to improve the efficiency and performance of currently operating combustion systems, the fuel economy, and the need to reduce pollutant emission. Normal-heptane is one of these hydrocarbons.  In this work a detailed chemical kinetic model for the oxidation and combustion of n-heptane has been automatically developed using a computer code called MOLEC. The model consisting of 486 species taking part in 2008 elementary reactions was used to reproduce experimental results of n-heptane oxidation in shock tubes. The experimental study of the ignition delay times of n-heptane/O2/Ar behind a reflected shock wave for equivalence ratios of 0.5-4.0 in a temperature range of 1300 K- 2000 K can be reproduced well by the model. Experimentally derived and numerically predicted ignition delays of n-heptane/air mixtures in a high-pressure shock tube in a wide range of temperatures, pressures, and equivalence ratios agree very well. Sensitivity analyses were performed for shock tube environment in an attempt to identify the most important reactions under the relevant conditions of study.Keywords: Modelling, Oxidation, Combustion, Kinetics, Fuels AbstrakDewasa ini di dunia muncul minat yang berkelanjutan dalam mengembangkan proses oksidasi dan pembakaran hidrokarbon panjang, yang merupakan representatif yang meyakinkan bagi  bahan bakar praktis yang digunakan di dalam mesin kendaraan bermotor dalam rentang kondisi operasi yang Iebar. Keminatan ini dipicu oleh keinginan untuk meningkatkan efisiensi dan kinerja sistem pembakaran yang digunakan saat ini, ekonomi bahan bakar serta kebutuhan untuk mengurangi emisi polutan. Normal-heptane merupakan salah satu hidrokarbon ini. Di dalam riset ini sebuah model kinetika kimia detail untuk oksidasi dan pembakaran n-heptana dikembangkan secara otomatis dengan menggunakan sebuah kode komputer yang disebut MOLEC. Model yang terdiri dari 486 spesies yang berperan serta di dalam 2008 reaksi elementer digunakan untuk mereproduksi hasil­ hasil eksperimen oksidasi n-heptana di dalam shock tubes. Has il eksperimen ignition delay times n­ heptana/ O2/Ar di dalam shock tube untuk rasio ekuivalensi 0,5-4,0 pada rentang temperatur 1300 K- 2000 K dapat direproduksi dengan baik oleh model. Ignition delay campuran n-heptanal udara hasil eksperimen dan hasil perhitungan numeris di dalam shock tube bertekanan tinggi dalam rentang temperatur, tekanan, dan rasio ekuivalensi yang luas sangat bersesuaian satu sama lain. Analisis sensitivitas dilakukan dalam upaya mengidentifkasi reaksi-reaksi yang paling penting di dalam kondisi kajian yang relevan.Kata Kunci: Modeling, Oksidasi. Pembakaran, Kinetika, Bahan Bakar


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.


2009 ◽  
Vol 32 (1) ◽  
pp. 477-484 ◽  
Author(s):  
D.R. Haylett ◽  
P.P. Lappas ◽  
D.F. Davidson ◽  
R.K. Hanson

2020 ◽  
Author(s):  
Nils Hansen ◽  
G. Kukkadapu ◽  
B. Chen ◽  
S. Dong ◽  
HJ Curran ◽  
...  

2014 ◽  
Vol 1070-1072 ◽  
pp. 549-552
Author(s):  
Yu Liu ◽  
Wen Zeng ◽  
Hong An Ma ◽  
Kang Yao Deng

In order to reduce the emission and realize the sustainable development in aviation industry, looking for alternative fuel as kerosene has become more and more important. Hydrogen is regarded as one of the most promising alternative fuels. In our study RP-3 kerosene with hydrogen addition is used as the alternative kerosene. A RP-3 kerosene surrogate includes n-decane, toluene and propyl cyclohexane (volume fraction is 0.65/0.1/0.25) was chosen and the ignition delay times are calculated in CHEMKIN-PRO, it is found that hydrogen addition can shorten ignition delay.


2016 ◽  
Vol 164 ◽  
pp. 152-163 ◽  
Author(s):  
Batikan Koroglu ◽  
Owen M. Pryor ◽  
Joseph Lopez ◽  
Leigh Nash ◽  
Subith S. Vasu

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