THE MECHANISM OF HEAT TRANSFER IN NUCLEATE POOL BOILING
MASSACHUSETTS INST OF TECH CAMBRIDGE DIV OF SPONSORED RESEARCH
Pagination or Media Count:
A criterion is developed for bubble initiation from a gas filled cavity on a surface in contact with a superheated layer of liquid. It is found that the temperature of bubble initiation on a given surface is a function of the temperature conditions in the liquid surrounding the cavity as well as the surface properties themselves and the delay time between bubbles is a function of the bulk liquid temperature and the wall superheat and is not constant for a given surface. With a thermal layer thickness and a critical wall superheat relation for the cavity, a bubble growth rate is obtained. Bubble departure is considered. The Jakob and Fritz relation works as long as the true non-equilibrium bubble contact angle is used. The effect on the departure size of the virtual mass in the surrounding liquid is negligible at one gravity. The initiation, growth and departure criterions are each experimentally checked and used to compute the heat transfer near the knee of the boiling curve using only an experimental determination of the number of bubbles as a function of wall superheat and other known quantities.