Cetane Effect on Diesel Ignition Delay Times Measured in a Constant Volume Combustion Apparatus

1995 ◽  
Author(s):  
Allen A. Aradi ◽  
Thomas W. Ryan
Keyword(s):  
Ignition Delay ◽  
Constant Volume ◽  
Ignition Delay Times ◽  
Delay Times ◽  
Combustion Apparatus ◽  
Constant Volume Combustion

Shockless Explosion Combustion: Experimental Investigation of a New Approximate Constant Volume Combustion Process

2016 ◽  
Author(s):  
Thoralf G. Reichel ◽  
Bernhard C. Bobusch ◽  
Christian Oliver Paschereit ◽  
Jan-Simon Schäpel ◽  
Rudibert King ◽  
...  
Keyword(s):  
Shock Waves ◽  
Ignition Delay ◽  
Gas Turbines ◽  
Control Algorithm ◽  
Ambient Pressure ◽  
Pressure Sensors ◽  
Constant Volume ◽  
Ignition Delay Times ◽  
Delay Times ◽  
Constant Volume Combustion

Approximate constant volume combustion (aCVC) is a promising way to achieve a step change in the efficiency of gas turbines. This work investigates a recently proposed approach to implement aCVC in a gas turbine combustion system: shockless explosion combustion (SEC). The new concept overcomes several disadvantages such as sharp pressure transitions, entropy generation due to shock waves, and exergy losses due to kinetic energy which are associated with other aCVC approaches like, e.g., pulsed detonation combustion. The combustion is controlled via the the fuel/air mixture distribution which is adjusted such that the entire fuel/air volume undergoes a spatially quasi-homogeneous autoignition. Accordingly, no shock waves occur and the losses associated with a detonation wave are not present in the proposed system. Instead, a smooth pressure rise is created due to the heat release of the homogeneous combustion. An atmospheric combustion test rig is designed to investigate the autoignition behavior of relevant fuels under intermittent operation, currently up to a frequency of 2Hz. Application of OH*- and dynamic pressure sensors allows for a spatially- and time-resolved detection of ignition delay times and locations. Dimethyl ether (DME) is used as fuel since it exhibits reliable autoignition already at 920K mixture temperature and ambient pressure. First, a model-based control algorithm is used to demonstrate that the fuel valve can produce arbitrary fuel profiles in the combustion tube. Next, the control algorithm is used to achieve the desired fuel stratification, resulting in a significant reduction in spatial variance of the auto-ignition delay times. This proves that the control approach is a useful tool for increasing the homogeneity of the autoignition.

Shockless Explosion Combustion: Experimental Investigation of a New Approximate Constant Volume Combustion Process

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Thoralf G. Reichel ◽  
Jan-Simon Schäpel ◽  
Bernhard C. Bobusch ◽  
Rupert Klein ◽  
Rudibert King ◽  
...  
Keyword(s):  
Shock Waves ◽  
Ignition Delay ◽  
Gas Turbines ◽  
Control Algorithm ◽  
Pressure Sensors ◽  
Constant Volume ◽  
Ignition Delay Times ◽  
Auto Ignition ◽  
Delay Times ◽  
Constant Volume Combustion

Approximate constant volume combustion (aCVC) is a promising way to achieve a step change in the efficiency of gas turbines. This work investigates a recently proposed approach to implement aCVC in a gas turbine combustion system: shockless explosion combustion (SEC). The new concept overcomes several disadvantages such as sharp pressure transitions, entropy generation due to shock waves, and exergy losses due to kinetic energy which are associated with other aCVC approaches such as pulsed detonation combustion. The combustion is controlled via the fuel/air mixture distribution which is adjusted such that the entire fuel/air volume undergoes a spatially quasi-homogeneous auto-ignition. Accordingly, no shock waves occur and the losses associated with a detonation wave are not present in the proposed system. Instead, a smooth pressure rise is created due to the heat release of the homogeneous combustion. An atmospheric combustion test rig is designed to investigate the auto-ignition behavior of relevant fuels under intermittent operation, currently up to a frequency of 2 Hz. Application of OH*– and dynamic pressure sensors allows for a spatially and time-resolved detection of ignition delay times and locations. Dimethyl ether (DME) is used as fuel since it exhibits reliable auto-ignition already at 920 K mixture temperature and ambient pressure. First, a model-based control algorithm is used to demonstrate that the fuel valve can produce arbitrary fuel profiles in the combustion tube. Next, the control algorithm is used to achieve the desired fuel stratification, resulting in a significant reduction in spatial variance of the auto-ignition delay times. This proves that the control approach is a useful tool for increasing the homogeneity of the auto-ignition.

scholarly journals Ignition delay times for jet and diesel fuels: Constant volume spray and gas-phase shock tube measurements

Fuel ◽  
2018 ◽  
Vol 219 ◽  
pp. 312-319 ◽  
Author(s):  
Sean Burden ◽  
Aniket Tekawade ◽  
Matthew A. Oehlschlaeger
Keyword(s):  
Shock Tube ◽  
Gas Phase ◽  
Ignition Delay ◽  
Constant Volume ◽  
Diesel Fuels ◽  
Ignition Delay Times ◽  
Delay Times

Ignition Characteristics of a Fischer-Tropsch Synthetic Jet Fuel

2008 ◽  
Author(s):  
P. Gokulakrishnan ◽  
M. S. Klassen ◽  
R. J. Roby
Keyword(s):  
Kinetic Model ◽  
Ignition Delay ◽  
Flow Reactor ◽  
Kinetic Mechanism ◽  
Jet Fuel ◽  
Synthetic Jet ◽  
Jet Fuels ◽  
Ignition Delay Times ◽  
Delay Times ◽  
Ignition Characteristics

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.

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
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