Laser Surface Engineering for Boiling Heat Transfer Applications

Nucleate boiling is inseparably connected with our everyday life. It is not only utilized in simple tasks like cooking, but it is also important for applications on various scales, ranging from enormous nuclear power plants to miniature microelectronics. This widespread integration is the result of its ability for effective heat transfer at low-temperature differences between the heated surface and the surrounding fluid. The surface wettability undoubtedly influences the boiling heat transfer, but the observed behaviour cannot be explained without taking into account the surface topography and chemical modifications due to intense boiling processes. This chapter demonstrates how nucleate boiling enhancement can be achieved on surfaces with various wetting properties and specific micro-/nanotopographical features, fabricated using a straightforward, robust and scalable laser-texturing approach. We discuss the basics of nucleate boiling and how it is affected by surface wettability; provide a fundamental background of laser surface engineering and its ability to achieve extreme wetting properties; and finally demonstrate the applicability of the laser-textured surfaces in enhancing and controlling nucleate pool boiling of different fluids. We show how laser surface engineering decreases the wettability effects on the key boiling parameters and – in this way – ensure more stable heat transfer performance.