有隔热涂层的气膜冷却火焰筒壁温计算

Wall Temperature Calculation of an Air-film Cooled Flame Tube with a Heat Insulation Coating

对薄壁火焰筒,给出了壁温计算模型和计算方法,应用该方法进行了某环管型燃烧室火焰筒壁温计算,查找了该燃烧室火焰筒一次主燃孔出现裂纹的原因,并研究了气膜冷却、隔热涂层及其厚度对壁温径向和轴向分布的影响。结果表明:火焰筒最高壁温946℃,符合火焰筒对最高壁温的设计要求;火焰筒一次主燃孔附近壁温分布梯度较大,是热应力易集中的地方,为查找火焰筒故障原因提供了依据;气膜冷却和隔热涂层能显著降低火焰筒壁温,有效改善壁温径向和轴向分布;隔热涂层厚度对火焰筒壁温影响很小。

With a thin-wall flame tube serving as an object of study,presented was a wall temperature calculation model and method for an air-film cooled flame tube with a heat insulation coating.By using the method in question,the wall temperature of the flame tube of an annular-tube combustor was calculated with the possible cause of a crack occurring to the primary main combustion hole of the flame tube being identified.In addition,the influence of the air-film cooling,heat insulation coating and its thickness on the radial and axial distribution of the flame tube wall temperature was also studied.The results of the study show that the maximum wall temperature of the flame tube at 946℃ can meet the design requirement for the maximum wall temperature of the flame tube.The wall surface temperature distribution gradient near the primary main combustion hole on the flame tube is relatively big,where a thermal stress concentration is liable to be located,providing an underlying basis for identifying the cause of any fault occurring to the flame tube.The air-film cooling and heat insulation coating can remarkably lower the wall temperature of the flame tube and effectively improve the wall temperature radial and axial distribution on the latter.The heat insulation coating thickness exercises a very small influence on the wall temperature of the flame tube.