Bubble dynamics of boiling of propane and iso-butane on smooth and enhanced tubes

Visualization experiments were carried out for nucleate pool boiling of propane and iso-butane on a horizontal smooth tube and two kinds of structured enhanced tubes. Some bubble dynamic parameters were measured. Comparisons were made between the smooth tube and the enhanced tubes for bubble growth rate, departure diameter, frequency, active site density, rise velocity and latent heat transfer. The effects of physical properties on the bubble dynamics are discussed. The present experimental results are compared with the model of Haider and Webb, relatively good agreement is found for enhanced surfaces. The augmentation mechanisms of heat transfer from structured enhanced tubes are also discussed.