Enhancement of condensation heat transfer at aluminum surfaces via laser-induced surface roughening

In this paper, condensation on plates with different rough-surface geometries has been experimentally investigated, and compared with smooth plates. The surface roughness on all plates was produced through laser marking with similar operational parameters of the device, and the roughened area on each plate was measured. The generated roughness on the plates was then examined through SEM images. Then, the values of heat flux and heat transfer coefficient were measured at different temperatures, according to the differences in the geometry of roughness generated on each plate, and compared. Investigation of the SEM images showed that the roughness created on the plates was in the form of cavities, with the mean diameter and depth of 50 and 5 mu m, respectively. The cavities were identical all through the roughened zones, despite the different geometries of the roughened surfaces on the plates. The obtained results revealed that the geometry and area of roughened zones on the plate were effective parameters in the measured values of heat transfer coefficient and heat flux, meaning that their combined effects might lead to an increase in heat flux and heat transfer coefficient values.

Automated summary

The geometry and area of roughened zones on the plate were found to be key parameters affecting the measured values of heat transfer coefficient and heat flux. Different geometries of roughened zones result in different heat transfer performance.