Porous media burners (PMBs) enable enhanced combustion performance by internally recirculating heat released from the combustion products upstream to the reactants via an inert solid matrix. Compared to conventional free-flame systems, PMBs are characterized by higher burning velocities, extended flammability, and lower emissions of NO_x. Current PMB implementations utilize a two-zone concept in which the flame stabilizes at the interface between two porous matrices of different topologies. In this work, a PMB design having a spatially graded porous matrix is proposed, supported by theoretical analysis of the governing equations and constitutive relations. Through computations and experiments, it is shown that the proposed physical design of the porous matrix results in a significant enhancement of the power-dynamic range and in excess of 50% higher blow-off limits compared to current designs. This is achieved through gradation in topology (i.e. porosity, pore diameter, cell diameter, etc.), which enables a continuous variation of radiative extinction properties as well as interphase heat exchange, allowing the flame to stabilize dynamically within the porous matrix and for a wider range of operating conditions.

多孔介质燃烧器（PMB）通过内部将惰性气体从上游燃烧产物释放的热量内部循环到反应物，从而提高燃烧性能。相比于传统的自由火焰系统，PMBS的特征在于较高的燃烧速度，延长可燃性和NO的排放更低_X 。当前的PMB实现采用两区概念，其中火焰稳定在具有不同拓扑结构的两个多孔矩阵之间的界面上。在这项工作中，在控制方程和本构关系的理论分析的支持下，提出了一种具有空间梯度多孔矩阵的PMB设计。。通过计算和实验表明，与目前的设计相比，所提出的多孔基体的物理设计可以显着提高功率动态范围，并可以将排气极限提高50％以上。这是通过拓扑结构的分级（即孔隙度，孔径，泡孔直径等）来实现的，它可以实现辐射消光特性的连续变化以及相间的热交换，从而使火焰在多孔基体内动态稳定。较宽的工作条件范围。