球形火焰锋面选取对计算层流燃烧速度的影响

Effects of spherical flame fronts selection on the calculation of laminar burning velocity

利用OpenFOAM建立了球形传播火焰数值模型,模拟了球形火焰传播过程.以甲烷-空气混合物为例,通过球形传播火焰实验获得了火焰半径时程数据并计算了层流燃烧速度,实验结果验证了模型的可靠性.在此基础上,研究了火焰锋面选取对球形传播火焰方法测量层流燃烧速度的影响.结果表明:在球形火焰传播过程中,若火焰结构无明显变化,则不同火焰锋面选取标准获得的火焰半径时程数据存在少量差异,这些差异主要是由火焰厚度引起的.当温度不合理时,使用非线性外推公式计算的层流燃烧速度会产生约6%的误差;而使用特定参数最大作为选取标准时则会产生约0.4%的误差.

A numerical model of spherical flame was established by OpenFOAM to simulate the process of spherical flame propagation.The methane-air mixtures were taken as an example,then the data of flames radius-time history were obtained through experiment,from which the laminar burning velocity(LBV)was calculated.The reliability of the numerical model was verified via the experimental results.Subsequently,the effects of the flame fronts selection on the measurement of LBVs with spherical flame were investigated.The results show that if there is no significant change in the flame structure during the process of spherical flame propagation,a small difference in the obtained flame radius-time history data is found due to the flame thickness.In addition,if the criteria are not suitable,the LBVs calculated by using the nonlinear extrapolation method will results in an error rate of 6%.And using the maximum specific parameter as the selection criterion will result in an error rate of approximately 0.4%.