Characterisation of two-stage ignition in diesel engine-relevant thermochemical conditions using direct numerical simulation

Krisman, Alex; Hawkes, Evatt R.; Talei, Mohsen; Bhagatwala, Ankit; Chen, Jacqueline H.

doi:10.1016/j.combustflame.2016.06.010

Title: Characterisation of two-stage ignition in diesel engine-relevant thermochemical conditions using direct numerical simulation

Full Record
Other Related Research

Abstract

With the goal of providing a more detailed fundamental understanding of ignition processes in diesel engines, this study reports analysis of a direct numerical simulation (DNS) database. In the DNS, a pseudo turbulent mixing layer of dimethyl ether (DME) at 400 K and air at 900 K is simulated at a pressure of 40 atmospheres. At these conditions, DME exhibits a two-stage ignition and resides within the negative temperature coefficient (NTC) regime of ignition delay times, similar to diesel fuel. The analysis reveals a complex ignition process with several novel features. Autoignition occurs as a distributed, two-stage event. The high-temperature stage of ignition establishes edge flames that have a hybrid premixed/autoignition flame structure similar to that previously observed for lifted laminar flames at similar thermochemical conditions. In conclusion, a combustion mode analysis based on key radical species illustrates the multi-stage and multi-mode nature of the ignition process and highlights the substantial modelling challenge presented by diesel combustion.

Authors:

^[1]; Hawkes, Evatt R. ^[2]; Talei, Mohsen ^[3]; Bhagatwala, Ankit ^[4]; Chen, Jacqueline H. ^[4]

Sandia National Lab. (SNL-CA), Livermore, CA (United States); The Univ. of New South Wales, Sydney, NSW (Australia)
The Univ. of New South Wales, Sydney, NSW (Australia)
The Univ. of Melbourne, Melbourne, VIC (Australia)
Sandia National Lab. (SNL-CA), Livermore, CA (United States)

Publication Date:: 2016-08-30

Research Org.:: Energy Frontier Research Centers (EFRC) (United States). Combustion Energy Frontier Research Center (CEFRC); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sandia National Lab. (SNL-CA), Livermore, CA (United States)

Sponsoring Org.:: USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:: 1326054

Alternate Identifier(s):: OSTI ID: 1358971

Report Number(s):: SAND-2016-5708J
Journal ID: ISSN 0010-2180; 643523

Grant/Contract Number:: AC04-94AL85000; SC0001198

Resource Type:: Accepted Manuscript

Journal Name:: Combustion and Flame

Additional Journal Information:: Journal Volume: 172; Journal Issue: C; Journal ID: ISSN 0010-2180

Publisher:: Elsevier

Country of Publication:: United States

Language:: English

Subject:: 97 MATHEMATICS AND COMPUTING; 33 ADVANCED PROPULSION SYSTEMS; diesel-relevant; autoignition; edge flame; cool flame; negative temperature coefficient; direct numerical simulation

Citation Formats


                    Krisman, Alex, Hawkes, Evatt R., Talei, Mohsen, Bhagatwala, Ankit, and Chen, Jacqueline H. Characterisation of two-stage ignition in diesel engine-relevant thermochemical conditions using direct numerical simulation.  United States: N. p., 2016. 
Web.  doi:10.1016/j.combustflame.2016.06.010.

Copy to clipboard


                    Krisman, Alex, Hawkes, Evatt R., Talei, Mohsen, Bhagatwala, Ankit, & Chen, Jacqueline H. Characterisation of two-stage ignition in diesel engine-relevant thermochemical conditions using direct numerical simulation.  United States.  https://doi.org/10.1016/j.combustflame.2016.06.010

Copy to clipboard


                    Krisman, Alex, Hawkes, Evatt R., Talei, Mohsen, Bhagatwala, Ankit, and Chen, Jacqueline H. Tue .  
"Characterisation of two-stage ignition in diesel engine-relevant thermochemical conditions using direct numerical simulation".  United States.  https://doi.org/10.1016/j.combustflame.2016.06.010.  https://www.osti.gov/servlets/purl/1326054.

Copy to clipboard


                    
@article{osti_1326054,

  title        = {Characterisation of two-stage ignition in diesel engine-relevant thermochemical conditions using direct numerical simulation},

  author       = {Krisman, Alex and Hawkes, Evatt R. and Talei, Mohsen and Bhagatwala, Ankit and Chen, Jacqueline H.},

  abstractNote = {With the goal of providing a more detailed fundamental understanding of ignition processes in diesel engines, this study reports analysis of a direct numerical simulation (DNS) database. In the DNS, a pseudo turbulent mixing layer of dimethyl ether (DME) at 400 K and air at 900 K is simulated at a pressure of 40 atmospheres. At these conditions, DME exhibits a two-stage ignition and resides within the negative temperature coefficient (NTC) regime of ignition delay times, similar to diesel fuel. The analysis reveals a complex ignition process with several novel features. Autoignition occurs as a distributed, two-stage event. The high-temperature stage of ignition establishes edge flames that have a hybrid premixed/autoignition flame structure similar to that previously observed for lifted laminar flames at similar thermochemical conditions. In conclusion, a combustion mode analysis based on key radical species illustrates the multi-stage and multi-mode nature of the ignition process and highlights the substantial modelling challenge presented by diesel combustion.},

  doi          = {10.1016/j.combustflame.2016.06.010},

  journal      = {Combustion and Flame},

  number       = C,

  volume       = 172,

  place        = {United States},

  year         = {2016},

  month        = {8}

}

Copy to clipboard

Journal Article:

Free Publicly Available Full Text

Accepted Manuscript (Publisher)

Accepted Manuscript (DOE)

Publisher's Version of Record

https://doi.org/10.1016/j.combustflame.2016.06.010

Other availability

Search WorldCat to find libraries that may hold this journal

Citation Metrics:

Cited by: 50 works

Citation information provided by
Web of Science

Save / Share:

Export Metadata

Save to My Library

Similar Records in DOE PAGES and OSTI.GOV collections:

A direct numerical simulation of cool-flame affected autoignition in diesel engine-relevant conditions

Conference Krisman, Alex ; Hawkes, Evatt R. ; Talei, Mohsen ; ... - Proceedings of the Combustion Institute

In diesel engines, combustion is initiated by a two-staged autoignition that includes both low- and high-temperature chemistry. The location and timing of both stages of autoignition are important parameters that influence the development and stabilisation of the flame. In this study, a two-dimensional direct numerical simulation (DNS) is conducted to provide a fully resolved description of ignition at diesel engine-relevant conditions. The DNS is performed at a pressure of 40 atmospheres and at an ambient temperature of 900 K using dimethyl ether (DME) as the fuel, with a 30 species reduced chemical mechanism. At these conditions, similar to diesel fuel,more »« less
https://doi.org/10.1016/j.proci.2016.08.043
Direct Numerical Simulations of Autoignition in Stratified Dimethyl-ether (DME)/Air Turbulent Mixtures

Journal Article Bansal, Gaurav ; Mascarenhas, Ajith ; Chen, Jacqueline H. - Combustion and Flame

In our paper, two- and three-dimensional direct numerical simulations (DNS) of autoignition phenomena in stratified dimethyl-ether (DME)/air turbulent mixtures are performed. A reduced DME oxidation mechanism, which was obtained using rigorous mathematical reduction and stiffness removal procedure from a detailed DME mechanism with 55 species, is used in the present DNS. The reduced DME mechanism consists of 30 chemical species. This study investigates the fundamental aspects of turbulence-mixing-autoignition interaction occurring in homogeneous charge compression ignition (HCCI) engine environments. A homogeneous isotropic turbulence spectrum is used to initialize the velocity field in the domain. Moreover, the computational configuration corresponds to amore »« less
Cited by 48
https://doi.org/10.1016/j.combustflame.2014.08.021

Full Text Available
DNS of a turbulent lifted DME jet flame

Journal Article Minamoto, Yuki ; Chen, Jacqueline H. - Combustion and Flame

A three-dimensional direct numerical simulation (DNS) of a turbulent lifted dimethyl ether (DME) slot jet flame was performed at elevated pressure to study interactions between chemical reactions with low-temperature heat release (LTHR), negative temperature coefficient (NTC) reactions and shear generated turbulence in a jet in a heated coflow. By conditioning on mixture fraction, local reaction zones and local heat release rate, the turbulent flame is revealed to exhibit a “pentabrachial” structure that was observed for a laminar DME lifted flame [Krisman et al., (2015)]. The propagation characteristics of the stabilization and triple points are also investigated. Potential stabilization points, spatialmore »« less
Cited by 42
https://doi.org/10.1016/j.combustflame.2016.04.007

Full Text Available
Unsteady deflagration speed of an auto-ignitive dimethyl-ether (DME)/air mixture at stratified conditions

Journal Article Desai, Swapnil ; Sankaran, Ramanan ; Im, Hong G. - Proceedings of the Combustion Institute

The propagation speed of an auto-ignitive dimethyl-ether (DME)/air mixture at elevated pressures and subjected to monochromatic temperature oscillations is numerically evaluated in a one-dimensional statistically stationary configuration using fully resolved numerical simulations with reduced kinetics and transport. Two sets of conditions with temperatures within and slightly above the negative temperature coefficient (NTC) regime are simulated to investigate the fundamental aspects of auto-ignition and flame propagation along with the transition from auto-ignitive deflagration to spontaneous propagation regimes under thermal stratification. Contrary to the standard laminar flame speed, the steady propagation speed of an auto-ignitive front is observed to scale proportionally tomore »« less
https://doi.org/10.1016/j.proci.2018.09.019
Unsteady deflagration speed of an auto-ignitive dimethyl-ether (DME)/air mixture at stratified conditions

Journal Article Desai, Swapnil S. ; Sankaran, Ramanan ; Im, Hong G. - Proceedings of the Combustion Institute

The propagation speed of an auto-ignitive dimethyl-ether (DME)/air mixture at elevated pressures and subjected to monochromatic temperature oscillations is numerically evaluated in a one-dimensional statistically stationary configuration using fully resolved numerical simulations with reduced kinetics and transport. Two sets of conditions with temperatures within and slightly above the negative temperature coefficient (NTC) regime are simulated to investigate the fundamental aspects of auto-ignition and flame propagation along with the transition from auto-ignitive deflagration to spontaneous propagation regimes under thermal stratification. Contrary to the standard laminar flame speed, the steady propagation speed of an auto-ignitive front is observed to scale proportionally tomore »« less
Cited by 7
https://doi.org/10.1016/j.proci.2018.09.019

Full Text Available

Similar Records