CHF in Oscillatory Flow Boiling Channels

Ledinegg instability in microchannels

“…Therefore, according to Eqs. (2) and (3), in the single-phase regime, the pressure drop is related to the size of the microchannel roughly by DP $ D À2 h at a given mass flux. Eqs.…”

“…Flow boiling oscillations modify the hydrodynamics of the flow, introduce severe structural vibrations, generate acoustic noise, and can jeopardize the structural integrity of the system. But, most importantly, flow oscillations can lead to the premature initiation of the critical heat flux condition [2][3][4], which, in turn, will result in a very ineffective heat transfer process; for heat flux controlled systems, elevated surface temperatures and possible complete destruction of the devices (burnout) may occur.…”

Forced flow boiling of carbon dioxide in horizontal mini-channel

“…When the density wave oscillation occurs, the oscillation is easily brought about to limit-cycle oscillations with large amplitudes, often accompanied by a flow reversal, and then the CHF reduces drastically, as exemplified in Fig. 20 [52], although the CHF in CO 2 system is not so serious as in a water system.…”

Critical Heat Flux Condition Induced by Flow Instabilities in Boiling Channels

“…Experimental investigations have been extensively conducted using a boiling channel system of water [e.g., 8,14]. The flow oscillation generated by an oscillator with a predetermined amplitude and period was imposed on the flow of constant mass flux supplied from a pump.…”

“…Umekawa et al [12] and Ozawa et al [14] conducted, however, the simplified numerical simulation based on the lumpedparameter model of the boiling channel. This model is based on three mutually interrelated dynamics of subcooled, boiling and superheated regions.…”