微小尺度下氢气预混燃烧的实验研究

对内径为1.66mm的不锈钢管燃烧室的氢气预混燃烧实验进行了描述，采用红外测温仪测量了燃烧室壁面的温度场分布，获得了不同燃烧热功率下的运行界限．在突扩段内高温回流区的作用下，在带有5mm长突扩段的燃烧室内可以实现完全预混燃烧，最高运行界限可达1.415．由于较高的进气速度和较大的燃烧室壁面散热，在不带突扩段的不锈钢管内无法实现完全预混燃烧．结果表明突扩段对微小尺度燃烧具有稳定火焰、拓宽燃烧运行界限的作用．通过对火焰形状和结构的观察，结合突扩段燃烧流场的分析，合理解释了燃烧室壁面温度场随过量空气系数的变化规律．

Experimental investigation of microscale premixed combustion of hydrogen

This paper describes the hydrogen and air premixed combustion in a stainless steel tube of 1.66 millimeter in diameter. Temperature fields of combustor wall are measured with infrared thermometer and operating ranges of different combustors are obtained at different thermal powers. With the help of recirculation zone in the facingback step, premixed combustion can be stabilized in the micro-combustor with a 5 mm-length facingback step and the maximum air excess coefficient is up to 1.415. But the premixed combustion can not be stabilized in the stainless steel tube without facingback step because of higher flow rate and great heat loss. It is proved that facingback step can steady the flame and enlarge the operating range for microscale combustion. The relation between temperature fields of combustor wall and air excess coefficient is reasonably interpreted by observing the shape and structure of the flame and analyzing flow fields of combustor with facingback step. The results can be used in designs of the microscale combustor.