Numerical study on mechanism of condensation oscillation of unstable steam jet. (16th January 2020)

• Record Type: Journal Article
• Authors: Song, Shilin; Yue, Xiaoyu; Zhao, Quanbin; Chong, Daotong; Chen, Weixiong; Yan, Junjie
• Is Part Of: Chemical engineering science. Volume 211(2020)
• Publication Date: 2020-01-16
• Subjects: Numerical simulation -- Steam bubble condensation -- Pressure oscillation -- Oscillation mechanism; Chemical engineering -- Periodicals; Génie chimique -- Périodiques; Chemical engineering; Periodicals; Electronic journals; 660
• DOI: 10.1016/j.ces.2019.115303
• Languages: English
• ISSNs: 0009-2509

Abstract

Highlights: Unstable steam jet in terms of bubble condensation was studied by CFD method. The dynamic condensation process of steam bubble was detailed explored. The mechanism of pressure oscillation was revealed. The effect of secondary bubble internal pressure on flow field was analyzed. Abstract: Submerged steam jet condensation is widely used in many industries. However, this process may cause damage to equipment due to pressure oscillation, especially at low steam mass flux. The dynamic process of steam bubble and different pressure oscillation types were investigated in this numerical study. Five typical stages were observed, which were bubble growth stage, bubble slow necking stage, bubble rapid necking stage, bubble detachment stage and secondary bubble oscillation stage. Two pressure oscillation types were found by the synchronization analysis of bubble pattern and pressure field. The mechanisms of condensation oscillation of unstable steam jet were revealed. As for the first type, two pressure peaks existed in the fluctuation process of secondary bubble volume. The higher pressure peak was generated when secondary bubble was oscillated to its minimum volume, and the other was generated when secondary bubble was collapsed. As for the second type, only one pressure peak existed and secondary bubble was quickly contracted without volume fluctuation. Pressure peak was generated when secondary bubble was quickly contracted to its minimum volume. Moreover, analyses of flow field pressure at different locations were carried out. Results indicated that the pressure fluctuation was mainly induced by the condensation oscillation of secondary bubble for both types. The trends of pressure at different locations were the same as that of secondary bubble internal pressure.