超临界压力下倾斜上升内螺纹管传热特性的试验研究

Experimental Study of Heat Transfer Characteristics Under Supercritical Pressure of Upwards Inclined Rifled Tubes

在超临界压力下,对倾角α=19.5°的φ28.6×5.8(mm)倾斜上升内螺纹管内水的传热特性及管壁温度分布进行了试验研究.试验参数范围:p=23～28 MPa,质量流速G=600～1200kg/(m2s),平均内壁热流密度q=300～600kW/m2.试验结果表明:管内螺纹造成的漩流作用可减弱内螺纹管截面上自然对流的影响.倾斜内螺纹管壁温及传热系数沿周向分布不均匀性很小.壁面热负荷越大,壁温越高;提高质量流速可降低壁温.在高焓值区,压力越高,传热越强.此外,还提出了传热系数的计算公式以供工程设计参考.

The heat transfer characteristics of water under supercritical pressure, together with the wall temperature distribution of upwards inclined （a = 19.5°） φ28.6 × 5.8 （mm） rifled tubes concerned, have been experimentally investigated. The test range was： p = 23.28 MPa, specific mass flow G = 600 - 1200 kg/m^2s, mean heat flux of the tubes＇ inner surface q = 300 - 600 kw/m^2 . Test results indicate that the circulating flow, initiated by the rifles, weakens the effect of natural circulation over the tubes＇ cross-sections. The nonuniformity of wall temperature distribution, and that of the heat transfer coefficient, along the tubes＇ circumference, is rather small. The wall temperature increases with increasing heat flux and reducess with increasing mass flow. In the high enthalpy region, heat transfer is intensified by rising pressure. A formula for calculating the heat transfer coefficient is moreover offered for design reference purposes. Figs 6, table 1 and refs 11.