燃气热水器用多孔介质燃烧器的结构设计与实验研究

Design and Experimental Study of A Variable Cross Section Porous Medium Burner for Gas Water Heater

针对现有多孔介质燃烧器的火焰面不稳定,易发生回火和脱火的技术问题,搭建了一组多孔介质燃烧器实验平台。其中多孔介质采用双层变截面的结构设计,燃烧器运用了特殊的防回火设计。通过计算机仿真以及燃烧实验研究了防回火装置的效果以及燃烧污染物排放特性。实验结果表明双层变截面的多孔介质有利于驻定火焰,提高多孔介质体的热量回流,更有效提高火焰传播速度,使多孔介质受热均匀。多孔介质稳定燃烧状态与过量空气系数相关。通过在多孔介质与预混腔之间增设防回火水管装置,不仅可以使预混气体分布更均匀还能利用水循环降低辐射热,对预防燃烧器回火起到了很好的效果。多孔介质稳定燃烧时产生的CO和NOx的排放量明显低于燃气热水器的国家标准。

A group of experimental platforms for porous medium burner has been built to address the technical issues of unstable flame surface and easy occurrence of backfire or lifting.The porous medium adopts the structural design of double-layer variable cross-section,and the burner uses a special anti backfire design.The characteristics of combustion flames and the effectiveness of anti backfire devices were studied through computer simulation and combustion experiments.The experimental results show that a double-layer porous medium with variable cross-section is beneficial for stationary flames,improving the heat reflux of the porous medium,and more effectively improving the flame propagation speed,making the porous medium uniformly heated.The stable combustion state of Porous medium is related to the excess air coefficient.By adding an anti backfire water pipe device between the porous medium and the premixed chamber,not only can the premixed gas distribution be more uniform,but also water circulation can be used to reduce radiation heat,which has a good effect on preventing burner backfire.The emissions of CO and NOx generated during the stable combustion of Porous medium are significantly lower than the national standards for gas water heaters.