Probability density function treatment of turbulence/chemistry interactions during the ignition of a temperature-stratified mixture for application to HCCI engine modeling

A DNS study of the ignition of lean PRF/air mixtures with temperature inhomogeneities under high pressure and intermediate temperature

“…It is worth mentioning that in addition to the DNS studies of HCCI combustion, there have been many attempts to develop and validate turbulent combustion models for large eddy simulations (LES) and Reynolds averaged Navier-Stokes simulations (RANS) based on DNS data. Several models including flameletbased models [56], probability density function (PDF) based models [57], and conditional moment closure (CMC) based model [58] for HCCI combustion have been proposed. These combustion models show good agreements with DNS results especially for small temperature and composition stratifications.…”

A Comparative Study of Conditional Moment Closure Modelling for Ignition of iso-octane and n-heptane in Thermally Stratified Mixtures

“…In this method, the PDF transport equation in the composition or velocity-composition space is solved using Eulerian fields or Lagrangian particles. Bisetti et al [27] considered a spatially homogeneous transported PDF model to simulate HCCI conditions and compared the results against DNS. Using this model, they were able to capture the correct quantitative trend for the time history of the heat release rate, and first and second moments of temperature and hydroxyl radical mass fraction.…”

“…The probability density function (PDF) method has also been used to simulate HCCI conditions [27,28]. In this method, the PDF transport equation in the composition or velocity-composition space is solved using Eulerian fields or Lagrangian particles.…”

Conditional moment closure modelling for HCCI with temperature inhomogeneities

“…However, DNS methods are not affordable as a design tool, which motivates the development of computationally cheaper models, such as flamelet-based models [17][18][19], probability density function models [20] or multi-zone approaches [4,21].…”

“…Published by Elsevier Inc. All rights reserved. processes, thermal stratification has a huge impact on both the timing and rate of heat release, as well as being an important influence on pollutant formation [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. Detailed, laser-based experiments have shown that temperature fluctuations always occur in HCCI engines; they have identified several sources for these fluctuations and contributed significantly to how they affect the process of ignition in the engine [1][2][3][4][5][6][7][8][9].…”