||Critical Heat Flux Phenomena Depending on Pre-pressurization in Transient Heat Input
Park, Jongdoc ,
Fukuda, KatsuyaLiu, Qiusheng
AIP Conference Proceedings
, p.080005 , 2017-07-21 , AIP Publishing
PROCEEDING OF THE 3RD INTERNATIONAL CONFERENCE OF GLOBAL NETWORK FOR INNOVATIVE TECHNOLOGY 2016 (3RD IGNITE-2016): Advanced Materials for Innovative Technologies. Conference date: 27–29 January 2016 Location: Penang, Malaysia. The critical heat flux (CHF) levels that occurred due to exponential heat inputs for varying periods to a 1.0-mm diameter horizontal cylinder immersed in various liquids were measured to develop an extended database on the effect of various pressures and subcoolings by photographic study. Two main mechanisms of CHF were found. One mechanism is due to the time lag of the hydrodynamic instability (HI) which starts at steady-state CHF upon fully developed nucleate boiling, and the other mechanism is due to the explosive process of heterogeneous spontaneous nucleation (HSN) which occurs at a certain HSN superheat in originally flooded cavities on the cylinder surface. The incipience of boiling processes was completely different depending on pre-pressurization. Also, the dependence of pre-pressure in transient CHFs changed due to the wettability of boiling liquids. The objective of this work is to clarify the transient CHF phenomena due to HI or HSN by photographic.