微尺度催化燃烧过程中传质准则数分析

Analysis of the Criterion Number of Mass Transfer in the Micro-scale Catalytic Combustion Process

在微尺度燃烧过程中,由于在很小的范围内各种中间组分和燃烧产物的传质和传热过程以及化学反应过程相耦合,因此微燃烧室内部的对流传质问题比较复杂。基于金属Pt壁面催化微燃烧室的模拟结果,分析了燃烧化学反应过程中组分OH的浓度梯度、传质和流动过程的计算结果,并结合无量纲分析法,推导出传质准则数舍伍德数Sh的数学表达式,通过OH的截面平均Shx去表征微燃烧过程中空间气相反应的变化,并分析入口参数对Shx的影响及空间气相反应与表面催化反应之间的抑制作用。

In the micro-scale conditions,due to the mass transfer and heat transfer coupling with the combustion process within the micro-combustor,the convection and mass transfer in the micro-combustor are rather complicated issues.In this paper,based on the simulation results of the Pt-based micro-scale catalytic combustion process and the concentration gradient,mass transfer and flow of the OH components in the micro-combustor,dimensionless analysis method was used to calculate the dimensionless Shx number which described the space gas phase reaction and mass transfer intensity in the channel cross-section away from the entrance at x.Then effects of inlet parameters on the dimensionless Shx number and the inhibition between the space gas phase reaction and catalytic reaction were analyzed.