Comparative analysis of boiling heat transfer on surfaces modified with thermal and mechanical techniques

Microstructural coatings enable large heat fluxes to be exchanged during nucleate boiling at small temperature differences. Such heat exchangers are highly efficient and can be used in various mechanical systems. The production techniques of selected types of microstructures (meshes, micro-fins, and longitudinal fins) are presented in the paper, with the main focus on the comparison of thermal performance of these heat-enhancing coatings during nucleate boiling of distilled water and ethyl alcohol. The comparison was done for the same structure height of ca. 0.90. The results indicate that generally, the highest performance was obtained with the laser–processed surface. The heat flux was even about 2.4 times higher for this type of structure than for the micro-fin surface. A modification to the selected model of boiling heat transfer on microstructural coatings was proposed and verified against the experimental data.