液氮防灭火工程中管道输送压降的计算方法
Calculation Methods of the Pipeline Transportation Pressure Drop in the Fire Prevention and Extinguishing Engineering with Liquid Nitrogen
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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。
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关键词:
- 液氮防灭火工程 /
- 两相氮压降 /
- 均相模型 /
- Lockhart-Martinelli 关联式
Abstract: 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 Lockhart-Martinelli correlation could be used to calculate the pressure drop of two-phase nitrogen except 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. -
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[1] 胡卫民，高新春，鹿广利. 矿井通风与安全[M].徐州：中国矿业大学出版社，2008：23-25. [2] STEINER D,SCHLUNDER E U. Heat transfer and pressure drop for boiling nitrogen Flowing in a horizontal tube 1. Saturated flow boiling[J].Cryogenics, 1976, 26(3): 387-398. [3] STEINER D,SCHLUNDER E U. Heat transfer and pressure drop for boiling nitrogen Flowing in a horizontal tube 2.Pressure drop[J].Cryogenics, 1976, 26(3): 457-464. [4] KLIMENKO V V, SUDARCHIKIOV A M. Investigation of forced flow boiling of nitrogen in a long vertical tube[J].Cryogenics,1983,23(3)：379-385. [5] 齐守良，张鹏，王如竹，等.微通道中液氮的流动沸腾—两相流动压降分析[J].机械工程学报，2007，43(5)：36-43. [6] Xiangdong Li, Rongshun Wang. Numerical and experimental investigation of pressure drop characteristics during upward boiling two-phase flow of nitrogen[J].International Journal of Heat and Mass Transfer, 2007(50):1971-1981. [7] 童钧耕，王平阳，苏永康. 热工基础[M].上海：上海交通大学出版社，2008：148-158. [8] 徐济鋆，鲁钟琪. 沸腾传热和气液两相流[M].北京：原子能出版社，1993：178. [9] 陈国邦，金滔，汤珂. 低温传热与设备[M].北京：国防工业出版社，2008：75-81. [10] 郭楚文，李意民，陈更林. 工程流体力学[M].徐州：中国矿业大学出版社，2010：123. [11] 陈国邦，黄永华，包锐. 低温流体热物理性质[M].北京：国防工业出版社，2006：190.
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