The dynamics of boiling succeeding spontaneous nucleation on a small film heater immersed in ethyl alcohol are investigated at heating rates ranging from 107 K/s to approximately 109 K/s, under which spontaneous nucleation is dominant for the inception of boiling. Immediately after the concurrent generation of a large number of fine bubbles, a vapor film that covers the entire surface is formed by coalescence and rapidly expands to a single bubble. As the heating rate is increased, the coalesced bubble flattens and only a thin vapor film grows before cavitation collapse. Similar behaviors are also observed for water. Based on the observed results, a theoretical model of the dynamic bubble growth due to the self-evaporation of the superheated liquid layer, which develops before boiling incipience, is presented. The calculated results are compared with the observed results.
|Number of pages||10|
|Journal||International Journal of Heat and Mass Transfer|
|Publication status||Published - Jul 2006|
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Mechanical Engineering
- Fluid Flow and Transfer Processes