摘要
We develop and assess a model of the turbulent burning velocity ST over a wide range of conditions.The aim is to obtain an explicit ST model for turbulent combustion modeling and flame analysis.The model consists of sub models of the stretch factor and the turbulent flame area.The stretch factor characterizes the flame response of turbulence stretch and incorporates detailed chemistry and transport effects with a lookup table of laminar counterflow flames.The flame area model captures the area growth based on Lagrangian statistics of propagating surfaces and considers the effects of turbulence length scales and fuel characteristics.The present model predicts sT via an algebraic expression without free parameters.We assess the model using 490 cases of the direct numerical simulation or experiment reported from various research groups on planar and Bunsen flames over a wide range of conditions,covering fuels from hydrogen to n-dodecane,pressures from 1 to 30 atm,lean and rich mixtures,turbulence intensity ratios from 0.1 to 177.6,and turbulence length ratios from 0.5 to 66.7.Despite the scattering sT data in the literature,the comprehensive comparison shows that the proposed ST model has an overall good agreement over the wide range of conditions,with the averaged modeling error of 28.1%.
本文提出并验证了一种适用于宽工况范围的湍流燃烧速度模型该模型具有显式表达式,可用于湍流燃烧理论分析和模型构建.模型主要由拉伸因子与湍流火焰面积两部分构成.拉伸因子描述了湍流拉伸导致的局部火焰速度变化.基于层流火焰的建表方法使拉伸因子模型能够考虑实际化学和输运特性的影响.火焰面积模型根据自传播面的拉格朗日统计信息刻画了湍流火焰面的增长规律,并考虑了湍流长度尺度和燃料特性的影响.模型参数主要由流动及火焰参数、通用常数和层流火焰结果查表得到,最后应用统一公式预测宽工况条件下的湍流燃烧速度变化.本文应用宽工况范围下的自由传播平面火焰与本生灯火焰直接数值模拟和实验数据对模型开展评估与验证.数据涵盖氢气至正十二烷等不同燃料、1-30个大气压、贫燃至富燃等不同当量比、湍流脉动速度与层流火焰速度比0.1-177.6,湍流积分长度尺度与层流火焰厚度比0.5-66.7等条件下的共490个湍流燃烧工况.对比不同工况的实验和模拟数据,模型预测的平均误差为28.1%.相较其他现有模型,该模型能正确描述不同燃料在宽工况范围下湍流燃烧速度变化趋势的差异.
基金
supported by the National Natural Science Foundation of China(Grant Nos.91841302,11925201,and 11988102)
the National Key Research and Development.Program of China(Grant No.2020YFE0204200)。
