竖管内淹没及其消失滞后问题的研究

STUDY ON FLOODING AND HYSTERESIS OF DEFLOODING IN VERTICAL TUBES

本文通过试验研究了竖管内淹没、流向反转以及淹没消失的滞后问题,研究了管径不同对这些过程的影响.采用无因次量J_g~*和J_L~*表达后,通过研究发现淹没开始点和流向反转点与管径无关;全部携带点与管径有关,而与注水量无关.根据试验结果给出了淹没过程中试验段内压差和流量的变化.当逐渐减少气体流量时,淹没点的消失会出现滞后,根据试验段的压差和流量变化分析了淹没消失滞后的原因和影响因素.根据试验数据整理出了相应的经验关系式.

In this paper, flooding, flow reverse and hysteresis effect of deflooding in vertical tubes have been studied, and the effect of tube diameter has also been studied in experiments. According to Wallis[1], using dimensionless parameters Jg* and Jl* as variable quantities, onset of flooding and flow reverse are independent of tube diameter, and the completed carry up is depend on tube diameter but independent of the flow rate of water injected. It is found from experiments that the smaller the tube diameter the higher the quantity Jg* for completed carry up, on completed carryup points Jg* is a constant in the Jg*1/2 and JL*1/2 coordinate.The changes of pressure difference and flow rates in test sections are given, hysteresis effect is found in deflooding with decreasing air flow rate, i.e. the air flow rate of deflooding is lower than that of onset of flooding in same flow rate of water injected. According to the change of pressure deference and flow rate in test section, the reasons and factors of hysteresis in deflooding are analyzed. Based on the experimental data, empirical correlations are obtained.