Assessment of chemical scalars for heat release rate measurement in highly turbulent premixed combustion including experimental factors

2018 ◽  
Vol 194 ◽  
pp. 485-506 ◽  
Author(s):  
Timothy M. Wabel ◽  
Peiyu Zhang ◽  
Xinyu Zhao ◽  
Haiou Wang ◽  
Evatt Hawkes ◽  
...  
Keyword(s):  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Premixed Combustion ◽  
Rate Measurement ◽  
Turbulent Premixed Combustion ◽  
Turbulent Premixed

Effects of Ambient Temperature and Oxygen Concentration on Soot Evolution in Diesel Spray Combustion

Volume 4 ◽  
2004 ◽  
Author(s):  
Yi Xu ◽  
Chia-Fon F. Lee
Keyword(s):  
Ambient Temperature ◽  
Heat Release ◽  
Oxygen Concentration ◽  
Heat Release Rate ◽  
Release Rate ◽  
Soot Formation ◽  
Premixed Combustion ◽  
Ambient Oxygen ◽  
Lower Heat ◽  
Soot Measurement

A newly developed Forward Illumination Light Extinction (FILE) soot measurement technique was applied in a constant volume spray chamber to study the effects of ambient temperature and oxygen concentration on soot evolution in diesel combustion. The FILE technique with the capability of two-dimensional time-resolved quantitative soot measurement provides the much-needed information to investigate the soot formation mechanism. The ambient temperatures of 1200K, 1000K and 800K were tested to study the temperature effects on soot formation. A decrease of ambient temperature results in a longer ignition delay, which promotes a larger premixed combustion zone combining with higher heat release rates. The change of ambient temperature from 1200K to 800K increases the fuel portion burnt in the premixed combustion period. At 800K, combustion is dominated by the premixed combustion and much less soot is formed. Diesel combustion with 21% and 15% ambient oxygen concentration was also studied. With lower ambient oxygen concentration, the combustion process is basically not changed, but expands into a longer time span with a lower heat release rate. The lower heat release rate results in a lower flame temperature, which benefits the NOx emission control. However, with about the same amount of soot within the flame, and much longer soot life, soot has more chance to escape to the exhaust.

Development of Diesel Engine Emissions Control Models Based on Heat Release Rate Analysis of Combustion Processes

2011 ◽  
Author(s):  
Dong Wang ◽  
Chao Zhang
Keyword(s):  
Diesel Engine ◽  
Numerical Simulations ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Control Model ◽  
Premixed Combustion ◽  
Linear Control ◽  
Control Models ◽  
Nox Control

Linear control models to control the Nitrogen Oxides (NOx) and soot emissions from a diesel engine were developed through numerical simulations. A modified KIVA-3V code was used to calculate the NOx and soot formations in a direct injection diesel engine under different operating conditions. The following relationships between the pollutant formations and the heat release rate were observed: 1) NOx formation amount is related to the peak value of the heat release rate and the timing of the premixed combustion; 2) soot formation amount is related to the peak heat release rate and the soot oxidation amount is related to the timing of the premixed combustion. Based on the above observations, linear control models for NOx and soot emissions were constructed. The NOx control model developed through the numerical simulations was implemented into the controller of an EGR valve on a small diesel engine. The experimental results showed that the NOx control model was effective in reducing NOx emissions under high RPM conditions.

On the correlation of heat release rate in turbulent premixed flames

2011 ◽  
Vol 33 (1) ◽  
pp. 1533-1541 ◽  
Author(s):  
N. Swaminathan ◽  
R. Balachandran ◽  
G. Xu ◽  
A.P. Dowling
Keyword(s):  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Premixed Flames ◽  
Turbulent Premixed Flames ◽  
Turbulent Premixed

Nonlinear combustion instability analysis of a bluff body burner based on the flame describing function

2021 ◽  
pp. 095441002110440
Author(s):  
Yipin Lu ◽  
Yinli Xiao ◽  
Juan Wu ◽  
Liang Chen
Keyword(s):  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Premixed Combustion ◽  
Single Frequency ◽  
Describing Function ◽  
Lean Premixed Combustion ◽  
Lean Premixed ◽  
Flame Describing Function ◽  
Frequency Harmonic

Lean premixed combustion is a common form of combustion organization in power equipment and propulsion systems. In order to understand the dynamic characteristics of lean premixed flame and predict and control its combustion instability, it is necessary to obtain its flame describing function (FDF). Based on the open source CFD toolbox, OpenFOAM, the dynamic K-equation model, and the finite rate Partially Stirred Reactor (PaSR) model were used to perform large eddy simulations (LES) of lean premixed combustion, and the response of the unsteady heat release rate to single-frequency harmonic disturbances was studied. The response of the unsteady heat release rate was characterized by the FDF, and the response of the unsteady heat release rate to the two-frequency harmonic disturbance was studied. The results show that the quantitative heat release rate response and flame dynamics have very proper accuracy. In the single-frequency harmonic disturbance, as the forcing frequency increases, the curling behavior of the flame surface and the instantaneous vortex structure change; the nonlinear kinematics effect is manifested by the entrainment of the vortex. At lower forcing frequencies, the heat release response changes linearly with the increase of forcing amplitude; at intermediate frequencies, the heat release response exhibits obvious nonlinear behavior; at high frequencies, the heat release response to amplitude changes decreases. The introduction of the second harmonic disturbance will significantly reduce the response range of the total heat release rate and make the combustion more stable.

Spatially resolved heat release rate measurements in turbulent premixed flames

2006 ◽  
Vol 144 (1-2) ◽  
pp. 1-16 ◽  
Author(s):  
B.O. Ayoola ◽  
R. Balachandran ◽  
J.H. Frank ◽  
E. Mastorakos ◽  
C.F. Kaminski
Keyword(s):  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Premixed Flames ◽  
Turbulent Premixed Flames ◽  
Spatially Resolved ◽  
Turbulent Premixed
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