Study on the transport process and heat transfer of boiling vapor film on PFA hydrophobic surface

Petroleum products are essential energy sources with increasing demand worldwide. At the same time, the storage of liquefied natural gas （LNG） in chemical plants is getting more and more attention, among which the boiling liquid expanding vapor explosion （BLEVE） accidents are the most common accidents in chemical plants, so how to reduce the boiling heat transfer coefficient （HTC） is very important. Compared to hydrophilic surfaces, hydrophobic surfaces have hydrophobic properties, which allow bubbles to link into a film at low heat flux and reduce the HTC. Based on the principle of surface wettability, different sizes of spherical tanks in the chemical plant are scaled down in equal proportions.The boiling process of PFA hydrophobic surfaces with different curvatures was investigated and compared with smooth copper surfaces by combining heat transfer data and visualization pictures. The results show that the critical heat flux density （CHF） and HTC of the surfaces coated with PFA hydrophobic coatings are significantly reduced, in which the highest HTC at the center angle of 0° of the four PFA hydrophobic surfaces with curvatures of 35⁻¹, 47⁻¹, 80⁻¹, and 120⁻¹ mm⁻¹ are reduced by 59.5%, 80.7%, 61.4% and 60.0%, respectively, in comparison with the curved smooth surfaces.