摘要
为了解微细直管燃烧器的工作特点,采用内径2 mm和1.4 mm的微细不锈钢管和陶瓷管进行氧气和甲烷气体的燃烧实验,研究了氧气和甲烷在微细管内的燃烧特点以及微细管的散热损失.研究结果表明,当量比小于1时,由于CH4没有完全被氧化,生成了大量的H2和CO气体,减小了燃烧反应的放热量.当量比等于1时,CH4被完全氧化为CO2和水蒸气,此时的放热量最大,同时管壁的散热量也最大.不锈钢管的散热量最大,是发热量的22%,陶瓷管的散热量最大达到了16%.不锈钢管的壁面发射率较大,辐射损失所占的比例较大,最大达到总散热量的70%.由于陶瓷管的导热系数比不锈钢管小,沿轴线方向的壁面温度梯度比不锈钢管大,这样不利于轴向的传热,以及火焰的稳定.
To understand working features of a micro-tube combustor, combustion of CH4/O2 was carried out in a ceramic tube with an inner diameter of 1.4 mm and a stainless steel tube with an inner diameter of 2 mm respectively. In the tests, combustion characteristics and heat loss of micro-tubes were studied. It is shown that when the equivalent ratio（ER） was less than 1, CH4 was not completely oxidized and a lot of gas H2 and CO were then produced, which lowered the combustion heat release. If ER equaled 1, CH4 was completely oxidized to gas CO2 and water vapor, and the reaction released the maximum combustion heat. Meanwhile, heat loss of the tube wall reached the highest. Heat loss of the stainless steel tube accounted for 22% of the heat release at most. Since wall emissivity of the stainless steel tube was larger than that of the ceramic tube, the radiative heat loss of the former was very large, accounting for 70% of the total heat loss at most. Additionally, because thermal conductivity of ceramic was less than that of stainless steel, temperature gradient along axis of the former was larger than that of the stainless steel tube, which was disadvantageous to axis heat transfer and flame stabilization.
出处
《燃烧科学与技术》
EI
CAS
CSCD
北大核心
2008年第3期199-204,共6页
Journal of Combustion Science and Technology
基金
国家自然科学基金资助项目(50376027)
关键词
微小燃烧室
甲烷
氧气
燃烧实验
热损失
micro-combustor
methane
oxygen
combustion test
heat loss
