流体障碍物作用下非均匀浓度场内火焰加速和DDT的机理研究

在脉冲爆轰发动机(PDE)实际工作及工业事故中，燃烧及DDT现象常常发生在具有浓度梯度的非均匀预混气中，同时，流体障碍物作为一种加速爆轰引发的新技术也开始得到关注。然而，现有非均匀浓度场内的火焰加速和DDT研究存在不足，而加入流体障碍物会导致更加复杂的物理现象，使得现有火焰加速机理和DDT规律的适用性面临极大挑战，亟需开展相关研究。因此，本项目将流体障碍物技术应用到非均匀浓度场中，用实验测试、数值模拟与理论分析相结合的方法研究燃烧过程，分析不同的浓度梯度对火焰加速的影响，获得不同参数的流体障碍物加速火焰传播和爆轰引发的过程，澄清非均匀浓度场内的火焰加速机理和DDT规律，阐明受限空间内非均匀浓度场中可燃预混气的爆轰动力学特征，建立适用于非均匀浓度场中DDT研究的流动/燃烧计算模型。相关研究有助于揭示流体障碍物作用下非均匀浓度场内火焰加速和DDT的内在机理，具有重要的科学意义和实际应用价值。

In the actual work of Pulse Detonation Engine (PDE) and industrial accident, combustion and Deflagration to Detonation Transition (DDT) often occur in the inhomogeneous premixed gas field with concentration gradient. Meanwhile, the study of fluidic obstacle which is regarded as a new detonation acceleration technology begins to get attention. However, the existing studies of flame acceleration and DDT in the inhomogeneous concentration field are insufficient, and the addition of fluidic obstacle will induce a more complicated physical phenomenon. Thus the applicability of the current flame acceleration mechanism and the DDT rules is facing great challenges, and this suggests an urgent need to carry out the relevant studies. Therefore, this project applies the fluidic obstacle to the inhomogeneous concentration field. Experimental, numerical and theoretical approaches will be adopted to study the combustion process. The influences of different concentration gradients on the flame acceleration are analyzed. The processes of flame propagation and detonation initiation with different fluidic obstacle parameters are acquired. The flame acceleration mechanism and the DDT rules in the inhomogeneous concentration field are clarified. Besides, in the confined space, the detonation characteristics of the combustible premixed gas are also illuminated. Moreover, a numerical model of the flow and combustion processes is established for the study of DDT in the inhomogeneous concentration field. The relevant studies help to reveal the internal mechanisms of the flame acceleration and DDT in the inhomogeneous concentration field which are affected by the fluidic obstacles, and the implementation of this project has vital scientific and practical significances.