不同化学热力学建表参数对火焰面模型精度的影响研究

Effects of different parametrization strategies to flamelet modeling accuracy

火焰面模型通过对燃烧过程的降维可以大幅减少求解燃烧场中化学反应所需的计算量.基于一维层流对撞火焰的数值解,构建了层流稳态火焰面模型(SFM)的化学热力学数据表并用于射流火焰的数值模拟.对所得到的火焰面数据表,分别采用基于混合分数和标量耗散率(Z,χZ)以及预混火焰面生成流形(FGM)方法中的混合分数和反应进度变量(Z,Yc)两种参数形式进行查表.通过火焰面坐标变换的方法,分析平面火焰中的流形特征,研究使用不同参数形式查询火焰面数据库对所得到的模拟结果的影响.两种查表方式得到的解与采用计算化学反应源项输运方程的直接数值求解方法(DNS)得到的解的对比结果表明,使用(Z,Yc)查表参数形式得到的解相比直接采用(Z,χZ)查表参数形式得到的解,更接近于DNS方法得到的解.

Application of flamelet model can lead to great reduction in computational cost through dimensional reduction of chemistry reacting system during combustion simulation .Steady laminar flamelet model was introduced into plan flame simulation ,with both parametrization form （Z ,χZ ） and （Z ,Yc ） applied .A general flamelet transformation was performed to explain the effects of different parametrization strategies to flamelet modeling accuracy by analyzing manifolds characteristic for planar flames .Solutions obtained by direct numerical simulation （DNS） were introduced as a reference to verify modeling accuracy . Comparisons between solutions obtained by different parametrization strategies show that application of （Z ,Y c ） parametrization form can achieve more accurate solutions close to the DNS ones than （Z ,χZ ） form .