Combustion characteristics of premixed propane/hydrogen/air in the micro-planar combustor with different channel-heights

Abstract

In order to improve the working performance and fuel adaptability of the micro-combustor, micro-planar combustors with different channel-heights are fabricated, and the three-dimensional calculation model is also built so as to study the basic characteristics of the blended propane/hydrogen combustion process. It is found that the hydrogen-addition method can overcome the shortcomings of propane flame instability under micro-scale conditions. When a small amount of hydrogen is added, the flame location could be fixed due to the stimulation of the important free radical like OH, thus obviously bringing the increase of mixture flammability range. The hydrogen-enriched fuel can further reduce the minimum flammable channel-height of propane. When the hydrogen addition ratio reaches 20%, a stable combustion will be achieved even in 1.5mm channel-height micro-combustor. Regardless of the 2.0mm or 2.5mm channel-height combustor, the effect of hydrogen addition will be better, and the flame location moves upstream gradually with the increase of hydrogen fraction. From the view of chemical energy utilization, the 2.0mm height combustor will be more suitable in the blended-fuel combustion mode, which is owing to the significant growth of the radiant energy output from the external wall.