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以氢气/空气预混气在2mm等径石英管中的当量比燃烧为对象,采用试验和数值模拟相结合的方法研究燃烧器及其内部的温度及温度梯度,分析热回流在来流气预热中的作用。在管子上游入口段,燃烧器外壁温度随环境热风温度和气流总流量的变化不大;最高外壁温度则随热风温度和气流总量的增加而明显升高。外壁上的热回流区域随着气流总流量增加而延长。在燃烧区域附近,管壁温度沿径向向外递减,温度轴向梯度可达105K/m,形成更强热回流。在燃烧器内部,径向截面上的气体最高温度点随着气流流动不断从外侧向中心移动直到燃烧区域,温度梯度可达106K/m。对于入口预热段和燃烧段中的未燃预混气体,从入口温度升到着火温度的热量主要来自上游火焰的热回流、外侧高温气体的预热和外侧火焰面的预热,前两者都源自气体或管壁的热回流。
In this paper, the equivalence ratio combustion of hydrogen / air pre-mixed gas in 2mm diameter quartz tube was taken as object. Combining experimental and numerical simulation, the temperature and temperature gradient inside the burner and its interior were studied. In the role. At the upstream inlet of the pipe, the temperature of the outer wall of the burner changes little with the ambient hot air temperature and the total air flow. The maximum outer wall temperature increases with the increase of hot air temperature and air flow. The hot return area on the outer wall is lengthened as the total airflow increases. In the vicinity of the combustion zone, the tube wall temperature decreases radially outward, the temperature of the axial gradient up to 105K / m, forming a more intense heat reflux. Inside the burner, the maximum temperature point of the gas in the radial section continuously moves from the outside to the center as the air current flows to the combustion area, and the temperature gradient reaches 106 K / m. For the unburned premix gas in the inlet preheating section and the combustion section, the amount of heat rising from the inlet temperature to the ignition temperature comes mainly from the thermal reflow of the upstream flame, the preheating of the outer hot gas and the preheating of the outer flame surface, Both are from the hot reflux of the gas or tube wall.