الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
The main objective of the present study is to investigate the effect of adding definite amounts of different surfactants to boiling distilled water on the nucleate pool boiling heat transfer performance using micro-structured heated tubes. Effects of wall heat flux, surface roughness, type of surfactant and its concentration in aqueous surfactant solutions (boiling fluids) on the nucleate boiling heat transfer coefficient are the major studied parameters. The tested surfactants are Sodium Dodecyl Sulfate (SDS) as anionic and Cetyl Trimethyl Ammonium Bromide (CTAB) as cationic. Six tested horizontal copper tubes are used; one is smooth, while the other tubes are roughened using sandblasting with different surface roughness parameters. A pool boiling test rig is designed and constructed to carry out heat transfer experiments. The effects of both of surfactants concentration and surface roughness on the heat transfer performance during pool boiling are studied. The experimental investigations showed that the addition of definite amounts of aqueous anionic and cationic surfactants (SDS and CTAB) to the water improves its physical and thermal properties and in turn improves the heat transfer coefficient in percentages reaching to 257 % for CTAB and 302 % for SDS using the most rough surface. A detailed analysis of the experimental data showed good enhancement
in the heat transfer coefficient for all test concentrations of SDS and
CTAB using the six test tube surfaces with different percentages.
The size distribution functions N(r) for the size of the stable vapor
bubbles in the active nucleation sites are deduced for the six test tubes
using different test concentrations of aqueous surfactant solutions.
ii
Attention is directed to correlate the experimental results of the wall
heat flux, surface roughness and aqueous surfactant solution
concentration; to get a helpful tool for predicting the enhancement of
the heat transfer coefficient during nucleate pool boiling. Reasonable
agreement is found between the present experimental data and the
available published data.