ISSN Online: 2377-424X
ISBN Print: 0-89116-559-2
International Heat Transfer Conference 8
BOILING NDCLEATION OF MIXTURES ON SMOOTH AND ENHANCED SURFACES
Abstrakt
In the present comprehensive experimental study, boiling activation and boiling deactivation superheats were obtained to investigate the effects of mixture composition and surface geometry on boiling nucleation. Also, contact angles were measured for the same mixtures on smooth surfaces of brass and copper. The boiling activation and deactivation superheats were observed to be complex functions of composition and they were much smaller for the enhanced boiling surface (High Flux) than for the plain, smooth surfaces. The classic boiling nucleation superheat equation ΔTsat = 2σ/[r(dP/dT)sat] was shown to be inadequate in predicting the trends in the data, even when taking into account the wetting effect and the measured non-linear variations in contact angle with composition. A number of new phenomena affecting nucleation were identified, which may explain the difference between the existing theory and the actual results.