ISSN Online: 2377-424X
ISBN Print: 0-85295-345-3
International Heat Transfer Conference 10
SIZE DISTRIBUTIONS OF ACTIVE NUCLEATION SITES WITH POOL BOILING HEAT TRANSFER AT SINGLE TUBES WITH DIFFERENT ROUGHNESSES
Resumo
Size distributions of active nucleation sites with
pool boiling heat transfer at single tubes with different
roughnesses have been calculated from measurements
with propane, n−hexane and R114 within wide ranges of
heat flux (50 to 105 W/m2) and pressure (1 to 90 per cent of the critical pressure). Model assumptions on the heat transfer connected with growing and detaching
bubbles have been modified, and it is shown that great
differences in the calculated data result from the great
scatter within the experimental data of bubble departure
diameter and frequency, existing in the literature. In addition, size distributions of form parameters are established
from measured surface roughness profiles of the
test tubes and compared with the size distributions of
bubble radii within the active nucleation sites.