摘要
结合煤矿液氮防灭火工程实际,在对液氮输送管道传热分析的基础上,介绍并比较了用均相模型和Lockhart-Martinelli关联式计算气液两相氮管道输送压降的方法,同时分析了管壁粗糙度、管道出口处气液两相氮干度、管径、质量流速对传输压降的影响。结果表明对于干度较小情况下的两相氮适合用均相模型计算,除环状流外,Lockhart-Martinelli关联式能较好地拟合气液两相氮的压降情况;管道壁面粗糙度对管道压降影响较大,且管径越小,壁面粗糙度对压降的影响越大;压降随管道出口两相氮干度的增加先增大后减小,可以在管壁外包裹绝热材料来减小出口干度,从而减小输送压降。
Combined with the engineering practice of coal mine fire prevention and extinguishing engineering with liquid nitrogen, on the basis of analyzing the heat transfer process in the liquid nitrogen transportation pipeline, it introduced and compared two calculation methods of two- phase nitrogen pipeline transportation pressure drop, which included homogeneous model and Lockhart -Martinelli correlation, then it analyzed the influence of wall roughness, dryness of two - phase nitrogen at the outlet of pipeline, pipeline diameter and mass flow speed on the pressure drop. The results showed that homogeneous model was suitable for calculating the pressure drop in the case of smaller dryness and Loekhart - Martinelli correlation could be used to calculate the pressure drop of two - phase nitrogen ex- eept the annular flow; the wall roughness greatly affected the pressure drop and the influence became bigger with the pipeline diameter becoming smaller; with dryness of two - phase nitrogen at the outlet of pipeline increasing, the pressure drop increased at first and then decreased, so wrapping the pipeline with insulation materials could reduce the dryness of two - phase nitrogen, thus it decreased the pressure drop.
出处
《煤矿安全》
CAS
北大核心
2013年第5期183-186,共4页
Safety in Coal Mines
基金
中央高校基本科研业务费专项资金资助项目(JX111742)
关键词
液氮防灭火工程
两相氮压降
均相模型
Lockhart-Martinelli关联式
fire prevention and extinguishing engineering with liquid nitrogen
two - phase nitrogen pressure drop
homogeneous model
Lockhart - Martinelli correlation
