A study on the mechanisms triggering the departure from nucleate boiling in subcooled vertical flow boiling using a complementary experimental approach. (January 2016)

• Record Type: Journal Article
• Authors: Bloch, Gregor; Bruder, Moritz; Sattelmayer, Thomas
• Is Part Of: International journal of heat and mass transfer. Volume 92(2016:Jan.)
• Page Start: 403
• Page End: 413
• Publication Date: 2016-01
• Subjects: Flow boiling -- CHF/DNB -- Mechanistic modeling -- Experimental validation; Heat -- Transmission -- Periodicals; Mass transfer -- Periodicals; Chaleur -- Transmission -- Périodiques; Transfert de masse -- Périodiques; Electronic journals; 621.4022
• DOI: 10.1016/j.ijheatmasstransfer.2015.08.063
• Languages: English
• ISSNs: 0017-9310

Abstract

Highlights: Complementary experimental approach on CHF using an array of measuring techniques. PIV, optical microprobes, holographic interferometry, shadowgraphy, high-speed photography. Critical review of CHF trigger mechanisms given in recent mechanistic models. New results on vapor behavior and heat distribution close to and during CHF. Conceptualization of a new mechanistic approach. Abstract: New experimental observations on the trigger mechanisms for the departure from nucleate boiling in subcooled flow boiling in a vertical, rectangular channel with an inner diameter of 40 mm are presented. A critical review of available mechanistic models and trigger mechanisms is given and a comparison to the experimental results is presented. Experimental results are derived using a matrix of complementary measuring techniques to review the validity of the proposed mechanisms for flow boiling of Novec 649. Mass fluxes are in the range of 500–2000 kg m −2 s −1 and subcoolings range from 27 to 9 K. A conceptualization for a refined phenomenological modeling approach is presented, and possible future research discussed.