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Title: Direct numerical simulation of ignition front propagation in a constant volume with temperature inhomogeneities. I. Fundamental analysis and diagnostics

Abstract

The influence of thermal stratification on autoignition at constant volume and high pressure is studied by direct numerical simulation (DNS) with detailed hydrogen/air chemistry with a view to providing better understanding and modeling of combustion processes in homogeneous charge compression-ignition engines. Numerical diagnostics are developed to analyze the mode of combustion and the dependence of overall ignition progress on initial mixture conditions. The roles of dissipation of heat and mass are divided conceptually into transport within ignition fronts and passive scalar dissipation, which modifies the statistics of the preignition temperature field. Transport within ignition fronts is analyzed by monitoring the propagation speed of ignition fronts using the displacement speed of a scalar that tracks the location of maximum heat release rate. The prevalence of deflagrative versus spontaneous ignition front propagation is found to depend on the local temperature gradient, and may be identified by the ratio of the instantaneous front speed to the laminar deflagration speed. The significance of passive scalar mixing is examined using a mixing timescale based on enthalpy fluctuations. Finally, the predictions of the multizone modeling strategy are compared with the DNS, and the results are explained using the diagnostics developed. (author)

Authors:
; ;  [1];  [2];  [3]
  1. Reacting Flow Research Department, Combustion Research Facility, Sandia National Laboratories, P.O. Box 969 MS 9051, Livermore, CA 94551-0969 (United States)
  2. Lockheed Martin Corporation, Sunnyvale, CA 94089 (United States)
  3. Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109-2125 (United States)
Publication Date:
OSTI Identifier:
20727298
Resource Type:
Journal Article
Resource Relation:
Journal Name: Combustion and Flame; Journal Volume: 145; Journal Issue: 1-2; Other Information: Elsevier Ltd. All rights reserved
Country of Publication:
United States
Language:
English
Subject:
33 ADVANCED PROPULSION SYSTEMS; FLAME PROPAGATION; IGNITION; COMBUSTION; TEMPERATURE GRADIENTS; TEMPERATURE RANGE 1000-4000 K; PRESSURE RANGE MEGA PA 01-10; INTERNAL COMBUSTION ENGINES; SIMULATION; MATHEMATICAL MODELS; HYDROGEN; ENTHALPY

Citation Formats

Chen, Jacqueline H., Hawkes, Evatt R., Sankaran, Ramanan, Mason, Scott D., and Im, Hong G.. Direct numerical simulation of ignition front propagation in a constant volume with temperature inhomogeneities. I. Fundamental analysis and diagnostics. United States: N. p., 2006. Web. doi:10.1016/j.combustflame.2005.09.017.
Chen, Jacqueline H., Hawkes, Evatt R., Sankaran, Ramanan, Mason, Scott D., & Im, Hong G.. Direct numerical simulation of ignition front propagation in a constant volume with temperature inhomogeneities. I. Fundamental analysis and diagnostics. United States. doi:10.1016/j.combustflame.2005.09.017.
Chen, Jacqueline H., Hawkes, Evatt R., Sankaran, Ramanan, Mason, Scott D., and Im, Hong G.. Sat . "Direct numerical simulation of ignition front propagation in a constant volume with temperature inhomogeneities. I. Fundamental analysis and diagnostics". United States. doi:10.1016/j.combustflame.2005.09.017.
@article{osti_20727298,
title = {Direct numerical simulation of ignition front propagation in a constant volume with temperature inhomogeneities. I. Fundamental analysis and diagnostics},
author = {Chen, Jacqueline H. and Hawkes, Evatt R. and Sankaran, Ramanan and Mason, Scott D. and Im, Hong G.},
abstractNote = {The influence of thermal stratification on autoignition at constant volume and high pressure is studied by direct numerical simulation (DNS) with detailed hydrogen/air chemistry with a view to providing better understanding and modeling of combustion processes in homogeneous charge compression-ignition engines. Numerical diagnostics are developed to analyze the mode of combustion and the dependence of overall ignition progress on initial mixture conditions. The roles of dissipation of heat and mass are divided conceptually into transport within ignition fronts and passive scalar dissipation, which modifies the statistics of the preignition temperature field. Transport within ignition fronts is analyzed by monitoring the propagation speed of ignition fronts using the displacement speed of a scalar that tracks the location of maximum heat release rate. The prevalence of deflagrative versus spontaneous ignition front propagation is found to depend on the local temperature gradient, and may be identified by the ratio of the instantaneous front speed to the laminar deflagration speed. The significance of passive scalar mixing is examined using a mixing timescale based on enthalpy fluctuations. Finally, the predictions of the multizone modeling strategy are compared with the DNS, and the results are explained using the diagnostics developed. (author)},
doi = {10.1016/j.combustflame.2005.09.017},
journal = {Combustion and Flame},
number = 1-2,
volume = 145,
place = {United States},
year = {Sat Apr 15 00:00:00 EDT 2006},
month = {Sat Apr 15 00:00:00 EDT 2006}
}