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在集总燃烧时滞模型的基础上,研究了系统耗散对燃烧稳定性的影响。通过在流动控制方程中考虑剪应力引起的阻尼项,利用燃烧锋面处的匹配边界条件,推导了考虑耗散效应的集总燃烧时滞模型。其次,采用Tim Liuwen等的研究方法,通过对不稳定燃烧试车数据进行滤波操作和相关性计算,间接获得了各阶声学模态对应的耗散系数。将其作为阻尼项加入到新的模型中,重新计算了本次试车的稳定性曲线。结果显示,各阶耗散系数均小于0.1,且耗散系数会随着模态阶数的提高而降低。另一方面,考虑耗散后的系统增益较原始模型及现有模型降低了48%,说明系统耗散的加入影响了模型的预测精度。进一步研究证明,耗散的增加会降低系统增益,从而提高其稳定性。
Based on the lumped model of combustion delay, the influence of system dissipation on combustion stability is studied. By considering the damping term caused by shear stress in the flow control equation and using the matching boundary conditions at the combustion front, a lumped combustion delay model considering the dissipation effect is derived. Secondly, based on the research method of Tim Liuwen et al., The dissipation coefficient corresponding to each acoustic mode is indirectly obtained through the filtering operation and correlation calculation of the unsteady combustion test data. Add it as a damping term to the new model and recalculate the stability curve of the test. The results show that the dissipation factor of each step is less than 0.1, and the dissipation factor decreases with the increase of the modal order. On the other hand, the system gain after dissipation is reduced by 48% compared with the original model and the existing model, indicating that the system dissipation affects the prediction accuracy of the model. Further studies have shown that increased dissipation reduces system gain, thereby increasing its stability.