Analysis of entropy generation and exergy loss during combustion

Nishida, Kosuke; Takagi, Toshimi; Kinoshita, Shinichi

doi:10.1016/s1540-7489(02)80111-0

Cited by 140 publications

(70 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Arpaci and Selamet [7] analyzed entropy generation in laminar premixed flames on a flat flame burner using analytical means and expressed the entropy generation rate in terms of the quenching distance. Nishida et al [8] analysed entropy generation mechanisms in laminar hydrogen-air and methane-air premixed flames based on detailed chemistry based simulations and demonstrated the effects of equivalence ratio on the entropy generation in premixed flames. Different mechanisms of entropy generation in multi-component reacting systems have been identified in a number of previous analyses [8][9][10][11][12][13][14][15] on premixed and non-premixed combustion.…”

Section: Introductionmentioning

confidence: 99%

“…To date, most analyses on local entropy generation mechanism have been carried out for laminar flows [7,8,[10][11][12][13][14] and relatively limited effort was given to the entropy generation mechanism in turbulent flames [14][15][16][17]. OKong'o and Bellan [16] and Safari et al [17] discussed the importance of the local entropy transport in the context of combustion modelling especially for Large Eddy Simulations (LES).…”

Section: Introductionmentioning

confidence: 99%

“…This void has been addressed here by analyzing entropy generation mechanisms in turbulent premixed flames based on three-dimensional compressible DNS data. As the nature of the fuel and the equivalence ratio of the mixture have significant influences on the entropy generation in turbulent premixed flames [8], a systematic parametric analysis based on DNS simulations has been carried out in this paper for different values of heat release parameter  and global Lewis number Le (as the equivalence ratio, nature of the fuel and the level of preheating can be characterized by  and Le). The heat release parameter  and global Lewis number Le are defined as follows:…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A Direct Numerical Simulation-Based Analysis of Entropy Generation in Turbulent Premixed Flames

Farran

Chakraborty

2013

Entropy

View full text Add to dashboard Cite

A compressible single step chemistry Direct Numerical Simulation (DNS) database of freely propagating premixed flames has been used to analyze different entropy generation mechanisms. The entropy generation due to viscous dissipation within the flames remains negligible in comparison to the other mechanisms of entropy generation. It has been found that the entropy generation increases significantly due to turbulence and the relative magnitudes of the augmentation of entropy generation and burning rates under turbulent conditions ultimately determine the value of turbulent second law efficiency in comparison to the corresponding laminar values. It has been found that the entropy generation mechanisms due to chemical reaction, thermal conduction and mass diffusion in turbulent flames strengthen with decreasing global Lewis number in comparison to the corresponding values in laminar flames. The ratio of second law efficiency under turbulent conditions to its corresponding laminar value has been found to decrease with increasing global Lewis number. An increase in heat release parameter significantly augments the entropy generation due to thermal conduction, whereas other mechanisms of entropy generation are marginally affected. However, the effects of augmented entropy generation due to thermal conduction at high values of heat release parameter are eclipsed by the increased change in availability due to chemical reaction, which leads to an increase in the second law efficiency with increasing heat release parameter for identical flow conditions. The combustion regime does not have any major influence on the augmentation of entropy generation due to chemical reaction, thermal conduction and mass diffusion in turbulent flames in comparison to corresponding laminar flames, whereas the extent of augmentation of entropy generation due to viscous dissipation in turbulent conditions in comparison to OPEN ACCESSEntropy 2013, 15 1541 corresponding laminar flames, is more significant in the thin reaction zones regime than in the corrugated flamelets regime. However, the ratio of second law efficiency under turbulent conditions to its corresponding laminar value does not get significantly affected by the regime of combustion, as viscous dissipation plays a marginal role in the overall entropy generation in premixed flames.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A Direct Numerical Simulation-Based Analysis of Entropy Generation in Turbulent Premixed Flames

Farran

Chakraborty

2013

Entropy

View full text Add to dashboard Cite

show abstract

“…In conventional engineering, the main concern is energy conversion without considering the exergy destruction. Analysis of exergy loss and entropy generation, which focuses on the optimal potential work done while bringing a system into equilibrium with an environment is an effective tool to investigate combustion efficiency and irreversibilities in combustion systems [2,3].…”

Section: Introductionmentioning

confidence: 99%

“…The vast majority of contributions so far has been on exergy analysis of combustion systems with laminar flow regimes [3,5,6,11,12,19,20]. Despite the prevalence of turbulence in practical combustion devices, the application of exergy analysis to turbulent reacting flows has been very limited [8,10,16,18].…”

Section: Introductionmentioning

confidence: 99%

Entropy Transport Equation in Large Eddy Simulation for Exergy Analysis of Turbulent Combustion Systems

Qariq

Sheikhi

Janbozorgi

et al. 2010

Entropy

View full text Add to dashboard Cite

The transport equation of entropy is introduced in large eddy simulation to perform exergy analysis of turbulent combustion systems. The sources of exergy destruction can be evaluated by analyzing entropy generation terms, which appear in unclosed forms in this equation. The closure is based on the filtered density function (FDF) methodology. The primary advantage of FDF is that chemical reaction and its entropy generation effects appear in closed forms. This methodology involves a stochastic model, which is being developed to account for the subgrid scale transport of entropy.

show abstract

Evaluation of an Entropy‐Based Combustion Model using Stochastic Reactors

2008

View full text Add to dashboard Cite

The entropy transport concept (ETC) presented in this paper is a novel approach to describe reaction systems such that the dynamic behavior of a chemical system can be reproduced with a minimum in independent parameters. It is shown that, for adiabatic conditions, the mixture fraction and the reaction entropy are sufficient to describe combustion processes without significant loss of information. Entropy is used as a measure of the reaction progress in this context. In order to evaluate the applicability of the ETC for combustion modeling in turbulent systems, the entropy transport concept was implemented into a stochastic reactor model. For several test cases, the results of this ETC-based reactor were compared with a reactor that directly integrates the species transport equations.

show abstract

Analysis of entropy generation and exergy loss during combustion

Cited by 140 publications

References 11 publications

A Direct Numerical Simulation-Based Analysis of Entropy Generation in Turbulent Premixed Flames

A Direct Numerical Simulation-Based Analysis of Entropy Generation in Turbulent Premixed Flames

Entropy Transport Equation in Large Eddy Simulation for Exergy Analysis of Turbulent Combustion Systems

Evaluation of an Entropy‐Based Combustion Model using Stochastic Reactors

Contact Info

Product

Resources

About