ISSN Online: 2379-1748
7th Thermal and Fluids Engineering Conference (TFEC)
SJR:
0.152
SNIP:
0.14
CiteScore™::
0.5
Indexed in
COMPUTATIONAL STUDY OF FORCE BALANCE DURING NUCLEATE BOILING
Abstract
Forces acting on a bubble growing on top of a heated surface have a profound impact on the dynamics of nucleate boiling. Bucci et al. [1] have recently experimentally showed that the Newton's second law is satisfied during the whole bubble growth cycle without the need of introduction of "special" forces, such as Londonvan der Waals forces, under moderate applied heat flux conditions. Thus, the ability to analyse the force balance in detail under a variety of conditions is paramount to the investigation of bubble detachment characteristics, which cannot be assumed to result from a simplified static balance approach. Direct Numerical
Simulation (DNS) is a perfect tool to perform such analysis. Using our validated DNS code, we demonstrate here that the findings of Bucci et al. hold under zero-gravity, hyper-gravity and inverted gravity conditions and can be reproduced in boiling simulations both with a modelled and with a resolved microlayer. The growing bubbles are shown to respond to the changes in gravitational conditions by altering their shape, i.e. by an adjustment of the hydrodynamic force acting on the bubble. This work represents another step in the development of a modern bubble detachment theory.