Rewetting of hot vertical tubes by a falling liquid film with different directions of venting the generated steam

Semi analytical parametric study of rewetting/quenching of hot vertical tube by a falling liquid film in the presence of countercurrent flow of rising vapors

“…Literature review of the subject of rewetting temperature reveals that an average value of rewetting temperature of 260 C is consistent with the finding of the experimental measurements [1,2,12,13], so this value is considered in the present work.…”

“…The literature review show that no analytical works take the effect of the countercurrent flow of rising vapor on the rewetting process. The unavailability of such analytical works and the limitations of the applicability of the results of Nada et al [1] and Nada [2] for specific geometric and operating parameters motivate the necessary of the present work. Therefore, the present work aims to analytically generalize the problem and parametrically study the phenomena for a wide range of the controlling parameters: tube dimensions, tube surface temperature, liquid injection rate and rate of countercurrent flow of rising vapors.…”

“…Recently, Nada et al [1] and Nada [2] conducted experimental investigations to study the effect of vapor generated from rewetting process and possibly gases from other sources on the rewetting rate of a vertical tubes by a falling liquid film. These studies were conducted for a specific geometric, operating and controlling parameters such as tube temperature and liquid film rates.…”

“…Later, Chan and Grolmes [30] and Block and Wallis [31] presented theoretical studies to examine whether the vapor generated during the quenching of a hot vertical tube is sufficient to reach the onset of flooding or not. Recently Nada et al [1] and Nada [2] published experimental investigations to study the effect of vapor generated from rewetting process and possibly air from other sources on the rate of rewetting of a vertical tubes by a falling liquid film. The studies showed that the countercurrent flow of generated vapors and rising air adversely affect the rewetting rate.…”

“…The present work aims to analytically treat the problem to parametrically study the phenomena for a wide range of the controlling parameters; tube dimensions, tube surface temperature, liquid injection rate and rate of countercurrent flow of rising vapors. Data of Nada [1] were utilized to identify the falling liquid/ upward vapor interfacial parameters needed by the analytical model.…”