ID#: 162
Abstract Title: Some Aspects on Level-set Modelling of Premixed Turbulent Combustion
Session Title: Premixed Turbulent Flames II
Session Date: 7/30/01
Session Start Time: 11:20 AM
Contributing Author: Nilsson, P.E.
Organization: Lund Institute of Technology
Country: Sweden
Authors: Per Nilsson, Xue-Song Bai
Short Abstract: A level-set flamelet library approach is investigated, especially in terms of the level-set flame position tracking formulation. Different methods for the numerical propagation of a distance function, denoting the distance to the mean flame surface, have been tested. One of them, the Fast Marching Method with extension velocities has shown beneficial thanks to the extension velocity algorithm. The mean turbulent flame is assumed to be an ensemble of locally laminar flamelets fluctuating around a mean flame position. Each flamelet has its own local structure of temperature and species as a function of the flamelet coordinate. This structure is simulated in a laminar flame calculation and stored in a table, called a flamelet library. The G-equation is employed to trace the mean flame surface, and a presumed Gaussian distribution of position around the surface is employed to average the locally laminar flamelet properties over the turbulent flame. The turbulent flow modelling frame work is that of standard k-epsilon and the computational field is discretized using Finite Differences on a staggered Cartesian grid. Measurements from the VAC Validation Rig 1, in which lean premixed propane/air V-shaped flame is stabilised behind a triangular prismatic flame holder in a rectangular channel, are utilised for some assessment of the simulated data.