旋流预混燃烧室燃烧特性研究

Investigation on combustion characteristics of swirl premixed combustor

以某型燃烧室为研究对象,采用RANS(Reynolds average navier-stokes)和LES(large eddy simulation)两种方法进行数值模拟,并对两种数值方法的模拟结果进行了对比分析。研究结果表明,RANS的计算结果能够反应燃烧场中的主要流场特征,具有一定的工程意义。LES能够复现弱轴向流动区等具体的流场细节,对剪切层位置和强度模拟较准确,还能模拟火焰动态发展过程,捕捉燃烧流场动态特性。与RANS相比,在燃烧流场数值仿真方面,LES占据更明显的优势。经计算,该工况下进动涡核由三个相对独立的螺旋涡分支组成,在燃烧室激起周期性速度脉动和压力脉动,LES捕捉到进动涡核主频率为156 Hz。

The numerical simulations are carried out by RANS(Reynolds Average Navier-Stokes) and LES(Large Eddy Simulation) to investigate the performance of a combustor. The research results show that RANS can reappear the main flow field characteristics in the combustion field, and it has some engineering significance. The LES can reproduce specific flow field details such as the weak central recirculation region, show the shear layer position and strength accurately, and perform continuous sequential dynamic calculation to exhibit the dynamic development process of the flame. Compared with RANS, LES has a more obvious advantage in numerical simulation of combustion flow field. The results show that the precesing vortex core is composed of three relatively independent spiral vortex branches under this condition, and it excites a periodic velocity and pressure pulsation in the combustor. The main frequency of the precessing vortex core captured by the LES is 156 Hz.