Physical Model of the Explosive Boiling

2 Onset of Nucleate Boiling in Parallel Micro-Channels 6.2.1 Physical Model of the Explosive Boiling 

Visual observation in the studies by Hetsroni et al. (2002a,b, 2003), Qu and Mudawar (2002) proved bubble behavior at incipient boiling in micro-channels (d i 1 mm) and concluded that it was quite different from that in larger channels. After nucleation, bubbles first grew to detachment size before departing into the liquid flow. The detachment size was comparable to that of the micro-channel 

A physical model of ONB for the explosive boiling and dryout, was suggested. In order to understand why dryout occurred even at a low value of vapor quality x, it is important to keep in mind that the liquid film does not cover the entire heated surface of the micro-channel, and two-phase flow is characterized by an unsteady cyclic behavior. The following assumptions are made in the development of the model  

The bubble nucleation occurs at the location where the wall temperature exceeds the saturation temperature. 

The heat flux is uniform and constant along the inner wall of the micro-channel. 

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