TITLE:
Evaluation of the Local Burning Velocity Using DNS Data of Turbulent Premixed Flames
AUTHORS:
Kazuya Tsuboi, Ryoji Matsugi, Eiji Tomita
KEYWORDS:
Local Burning Velocity, Integration Range, Reaction Progress Variable, Turbulent Premixed Flame, Direct Numerical Simulation
JOURNAL NAME:
Natural Science,
Vol.6 No.12,
August
27,
2014
ABSTRACT: The
local burning velocity, which is based on the consumption rate of the unburned
mixture, is one of the dominant parameters in turbulent premixed flames. In
this study, the evaluating method of the local burning velocity was
investigated using DNS data of turbulent premixed flames with different Lewis
numbers. The local burning velocity was evaluated by integrating the chemical
reaction rates along normal to the flame surface within three kinds of
integration ranges that were defined as follows: the range which is defined by
the half length of normal to the flame surface between its certain point and
the other point crossing the flame surface (Range 1); the range which is
defined by the reaction progress variable that the chemical reaction rate along
normal to a planer flame surface takes a half of the maximum value (Range 2);
the range which is defined by the length of normal to the flame surface between
its certain point and the point which has the extreme value of the reaction
progress variable (Range 3). As a result, Range 1 and Range 2 were affected by
the flame shapes greatly, since the quantities of the integration ranges fluctuated
widely dependent on the variations of turbulent premixed flames. Under the
conditions of the turbulent combustion in this study, Range 3, which is hardly
affected by a flame shape, is considered to be appropriate to the evaluation of
the local burning velocity.