Effect of tube diameter on flooding
TL;DR: In this article, the effect of tube diameter on the mechanism of flooding in vertical gas-liquid countercurrent annular flow was investigated. But the results indicated that the mechanism was qualitatively different in the small and the large diameter test sections.
Abstract: This paper describes an experimental study on the effect of tube diameter on the mechanism of flooding in vertical gas–liquid countercurrent annular flow. Flooding experiments were conducted with three different tube inner diameters, namely, 25, 67 and 99 mm with smooth inlet and outlet conditions for air and water. The results indicate that the mechanism of flooding is qualitatively different in the small and the large diameter test sections. While flooding in the 25 mm diameter section occurred essentially by the upward movement of large waves created near the liquid outlet, no such waves could be seen in the 67 and the 99 mm diameter test sections. Here, flooding occurred by droplet carryover or by an unstable, churn-like motion in the liquid film. The results are compared with existing correlations. The effect of test section length on flooding was also investigated.
Cites background from "Effect of tube diameter on flooding..."
...properties, bubble coalescence, liquid and gas entrainment, but also the entrance conditions at the bottom of the pipe [Lucas et al., 2005; Delnoij et al., 1997; Kozma, 1995; Vijayan et al., 2001]....
...…controlling the two-phase flow patterns are the liquid and gas fluxes, conduit geometry, liquid properties, bubble coalescence, liquid and gas entrainment, but also the entrance conditions at the bottom of the pipe [Lucas et al., 2005; Delnoij et al., 1997; Kozma, 1995; Vijayan et al., 2001]....
"Effect of tube diameter on flooding..." refers methods in this paper
...Richter (1981) and Jayanti et al. (1996) suggested, based on dierent arguments, that the Wallis-type correlation would work well in small diameter tubes and the Kutateladze-type in large diameter tubes....
...Among the semi-empirical correlations, they found that the correlation of Bharathan et al. (1978) performed the best with a weighted error of 35% 2f w U Ã2 L 1 À a 2 2f i U Ã2 G a 2:5 1 À a; 9 f i f w 14:6 1 À a 1:87 ; f w 0:005: 10 In view of these recommendations, the data…...
"Effect of tube diameter on flooding..." refers background or methods in this paper
...For example, McQuillan et al. (1985) and Govan et al. (1991) , among others, used slight depressurization , of the order of 0.05 bar, to induce ¯ooding while others such as Dukler and Smith (1982) and Zabaras and Dukler (1988) induced ¯ooding by gradually increasing the air ¯ow rate....
...It is generally believed (Suzuki and Ueda, 1977; McQuillan et al., 1985; Govan et al., 1991) that ¯ooding occurs when large waves, formed near the liquid outlet, are swept upwards by the gas phase....
...In some cases, this discrepancy can be attributed to the inlet and outlet conditions for the gas and liquid phases (Govan et al., 1991), however, the experiments of International Journal of Multiphase Flow 27 (2001) 797±816 www.elsevier.com/locate/ijmul¯ow Biage (1989) showed that even with smooth…...
...The ®rst mechanism, namely, upward transport of ring-type waves, has been observed, among others, by Suzuki and Ueda (1977), McQuillan et al. (1985) and Govan et al. (1991)....
...As a modi®cation to (ii) above, Govan et al. (1991) de®ned ¯ooding as the point at which liquid appeared (and not necessarily carried away by the gas stream) above the liquid injection point....
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