湍流分层燃烧的直接数值模拟和小火焰模型研究

湍流分层燃烧广泛应用于工业燃烧装置,但是目前还比较缺乏适用于湍流分层燃烧的高精度数值模型。本文利用直接数值模拟数据库,对高Karlovitz数分层射流火焰的小火焰模型表现进行了先验性评估。考虑了两种小火焰模型,一种是基于自由传播层流预混火焰的小火焰模型M1,另一种是基于分层对冲小火焰的小火焰模型M2。研究发现M1和M2在c-Z空间的结果与直接数值模拟在定性上是一致的。在物理空间,M2对过程变量反应速率脉动值的预测结果要优于M1.

Direct Numerical Simulation of Turbulent Stratified Combustion and Study of Flamelet Model

Turbulent stratified premixed combustion is widely used in industrial applications.However,combustion models for turbulent stratified premixed combustion have not been well studied in the literature.In this paper,a direct numerical simulation(DNS)database of a high Karlovitz number stratified premixed jet flame is used to evaluate the performance of different flamelet models in an a-priori sense.Two flamelet models were considered with Ml being based on freely propagating laminar premixed flames and M2 based on laminar stratified premixed flames.The results demonstrate that in c-Z space,the predictions of M1 and M2 qualitatively agree with that of the DNS.In physical space,M2 provides better predictions than Ml for the fluctuation of the process variable source term.