This article reviews the recent research on the effect of micro- and nanomodified surfaces and coatings on heat-transfer enhancement and critical heat fluxes (CHFs) at boiling. The first part contains a detailed review of papers devoted to investigation of boiling heat transfer and crisis phenomena in nanofluids. The interest in this field is caused by a significant increase in the CHF value at boiling of nanofluid due to the sedimentation of nanoparticles and altered wettability and porosity of heat-releasing surfaces. Possible mechanisms of the increase in CHF and the main disadvantages of using nanofluids in practical applications are discussed. The second part is devoted to various techniques that are used to create micro- and nanostructured heat-exchange surfaces and to research the effect of modified heaters on boiling performance.

Evaporating water drops on a horizontal heated substrate were investigated experimentally. The heater was made of a constantan foil with the thickness of 25 μm and size of 42 × 35 mm². The temperature of the bottom foil surface was measured by the infrared (IR) camera. To determine the heat flux density during evaporation of liquid near the contact line, the Cauchy problem for the heat equation was solved using the temperature data. The maximum heat flux density is obtained in the contact line region and exceeds the average heat flux density from the entire foil surface by the factor of 5–7. The average heat flux density in the region wetted by the drop exceeds the average heat flux density from the entire foil surface by the factor of 3–5. This fact is explained by the heat influx from the foil periphery to the drop due to the relatively high heat conductivity coefficient of the foil material and high evaporation rate in the contact line region. Heat flux density profiles for pairs of sessile droplets are also investigated.

The paper presents the results of an experimental study of the effect of hydrophobic fluoropolymer coating on the multiscale characteristics of heat transfer at water boiling. New experimental data on dynamics of vapor bubble growth and detachment, evolution of contact line, nucleation site density, heat transfer coefficient were obtained using high-speed imaging techniques, including infrared thermography and video recording from the bottom side of transparent ITO heater. It was shown that the using of hydrophobic fluoropolymer coating leads to heat transfer enhancement, to decrease of the surface temperature at the onset of boiling, to increase of nucleation site density and to significant change in the dynamics of growth and departure of vapor bubbles and the evolution of the triple contact line.