The Shock Tube Autoignition of Biodiesels and Biodiesel Components

2013 ◽  
Author(s):  
Weijing Wang ◽  
Matthew A. Oehlschlaeger
Keyword(s):  
High Temperature ◽  
Methyl Ester ◽  
Shock Tube ◽  
Ignition Delay ◽  
Methyl Esters ◽  
Acid Methyl Ester ◽  
Oh Radicals ◽  
Reflected Shock ◽  
Ignition Delay Times ◽  
Delay Times

The autoignition of fatty-acid methyl ester biodiesels and methyl ester biodiesel components was studied in gas-phase shock tube experiments. Ignition delay times for two reference methyl ester biodiesel fuels, derived from methanol-based transesterification of soybean oil and animal fats, and four primary constituents of all methyl ester biodiesels, methyl palmitate, methyl stearate, methyl oleate, and methyl linoleate, were measured behind reflected shock waves for fuel/air mixtures at temperatures ranging from 900 to 1350 K and at pressures around 10 and 20 atm. Ignition delay times were determined by monitoring pressure and chemiluminescence from electronically-excited OH radicals around 310 nm. The results show similarity in ignition delay times for all methyl ester fuels considered, irrespective of the variations in organic structure, at the high-temperature conditions studied and also similarity in high-temperature ignition delay times for methyl esters and n-alkanes.

High Pressure Ignition of Boron in Reduced Oxygen Atmospheres

1995 ◽  
Vol 418 ◽  
Author(s):  
R. O. Foelsche ◽  
M. J. Spalding ◽  
R. L. Burton ◽  
H. Krier
Keyword(s):  
High Pressure ◽  
Water Vapor ◽  
Shock Tube ◽  
Ignition Delay ◽  
Peak Pressure ◽  
Reflected Shock ◽  
Ignition Delay Times ◽  
Fluorine Compounds ◽  
Delay Times ◽  
Tube Study

AbstractBoron ignition delay times for 24 μm diameter particles have been measured behind the reflected shock at a shock tube endwall in reduced oxygen atmospheres and in a combustion bomb at higher pressures in the products of a hydrogen/oxygen/nitrogen reaction. The shock tube study independently varies temperature (1400 – 3200 K), pressure (8.5, 34 atm), and ignition-enhancer additives (water vapor, fluorine compounds). A combustion chamber is used at a peak pressure of 157 atm and temperature in excess of 2800 K to study ignition delays at higher pressures than are possible in the shock tube.

Autoignition Variation of Biodiesel Surrogates: Influence of Saturation

2013 ◽  
Author(s):  
Weijing Wang ◽  
Sandeep Gowdagiri ◽  
Matthew A. Oehlschlaeger
Keyword(s):  
Low Temperature ◽  
High Temperatures ◽  
Ignition Delay ◽  
Acid Methyl Ester ◽  
Negative Temperature ◽  
Carbon Chain ◽  
Reflected Shock ◽  
Ignition Delay Times ◽  
Temperature Regimes ◽  
Delay Times

The autoignition of three biodiesel surrogates (methyl decanoate, methyl 9-decenoate, and a mixture of methyl 5-decenoate and methyl 6-decenoate), representative of the organic structures found in fatty-acid methyl ester (FAME) biodiesels, has been studied using the reflected shock technique. Measurements of ignition delay times were carried out at 20 atm for temperatures ranging from 700 to 1300 K, spanning all three regimes of reactivity of interest to diesel engines. At high temperatures (> 900 K) the three surrogate components have indistinguishable ignition delay. While in the negative-temperature-coefficient (NTC) and low-temperature regimes (< 900 K) the deviation in ignition delay based on the location of the double bond with the methyl decenoate carbon chain is around a factor of two. The results show that location of double bonds within FAME biodiesel components will have an important role in governing the NTC and low-temperature reactivity for FAME biodiesels but is unimportant at high-temperatures, of significance for the development of biodiesel surrogates and modeling strategies for diesel engine simulations.

High-Pressure Oxy-Syngas Ignition Delay Times With CO2 Dilution: Shock Tube Measurements and Comparison of the Performance of Kinetic Mechanisms

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Samuel Barak ◽  
Erik Ninnemann ◽  
Sneha Neupane ◽  
Frank Barnes ◽  
Jayanta Kapat ◽  
...  
Keyword(s):  
Experimental Data ◽  
Shock Tube ◽  
Ignition Delay ◽  
Current Data ◽  
Reflected Shock ◽  
Ignition Delay Times ◽  
Delay Times ◽  
Syngas Combustion ◽  
Kinetic Mechanisms ◽  
Data Points

In this study, syngas combustion was investigated behind reflected shock waves in CO2 bath gas to measure ignition delay times (IDT) and to probe the effects of CO2 dilution. New syngas data were taken between pressures of 34.58–45.50 atm and temperatures of 1113–1275 K. This study provides experimental data for syngas combustion in CO2 diluted environments: ignition studies in a shock tube (59 data points in 10 datasets). In total, these mixtures covered a range of temperatures T, pressures P, equivalence ratios φ, H2/CO ratio θ, and CO2 diluent concentrations. Multiple syngas combustion mechanisms exist in the literature for modeling IDTs and their performance can be assessed against data collected here. In total, twelve mechanisms were tested and presented in this work. All mechanisms need improvements at higher pressures for accurately predicting the measured IDTs. At lower pressures, some of the models agreed relatively well with the data. Some mechanisms predicted IDTs which were two orders of magnitudes different from the measurements. This suggests that there is behavior that has not been fully understood on the kinetic models and is inaccurate in predicting CO2 diluted environments for syngas combustion. To the best of our knowledge, current data are the first syngas IDTs measurements close to 50 atm under highly CO2 diluted (85% per vol.) conditions.

Application of an aerosol shock tube to the measurement of diesel ignition delay times

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

scholarly journals Shock tube ignition delay times and methane time-histories measurements during excess CO2 diluted oxy-methane combustion

2016 ◽  
Vol 164 ◽  
pp. 152-163 ◽  
Author(s):  
Batikan Koroglu ◽  
Owen M. Pryor ◽  
Joseph Lopez ◽  
Leigh Nash ◽  
Subith S. Vasu
Keyword(s):  
Shock Tube ◽  
Ignition Delay ◽  
Methane Combustion ◽  
Ignition Delay Times ◽  
Delay Times ◽  
Time Histories

Comparison Between RCCE and Shock Tube Ignition Delay Times at Low Temperatures

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Ghassan Nicolas ◽  
Hameed Metghalchi
Keyword(s):  
Free Energy ◽  
Shock Tube ◽  
Ignition Delay ◽  
Low Temperatures ◽  
Reduction Technique ◽  
Experimental Measurements ◽  
Ignition Delay Times ◽  
Delay Times ◽  
Constrained Equilibrium ◽  
Rate Controlled

The rate-controlled constrained-equilibrium (RCCE) method is a reduction technique based on local maximization of entropy or minimization of a relevant free energy at any time during the nonequilibrium evolution of the system subject to a set of kinetic constraints. In this paper, RCCE has been used to predict ignition delay times of low temperatures methane/air mixtures in shock tube. A new thermodynamic model along with RCCE kinetics has been developed to model thermodynamic states of the mixture in the shock tube. Results are in excellent agreement with experimental measurements.

Ignition delay times of methane fuels at thrust chamber conditions in an ultra-high-pressure shock tube

2022 ◽  
Author(s):  
Michael Pierro ◽  
Andrew Laich ◽  
Justin J. Urso ◽  
Cory Kinney ◽  
Subith Vasu ◽  
...  
Keyword(s):  
High Pressure ◽  
Shock Tube ◽  
Ignition Delay ◽  
Pressure Shock ◽  
Thrust Chamber ◽  
Ultra High Pressure ◽  
Ignition Delay Times ◽  
Delay Times
Sign in / Sign up

Export Citation Format

Share Document