Droplet evaporation on a heated structured wall

Abstract

Evaporation of water droplets on a structured surface is studied experimentally. With an increase in the wall temperature T w from 28-70 °С the exponent n increases from 1-1.37 in the evaporation law (j = dm/dt ~ R 0 n , where m is the droplet mass and R 0 is the droplet radius). Usually, researchers simulating droplet evaporation consider a linear relationship between the evaporation rate, j, and the droplet radius, R 0 (n = 1). This paper shows an increase of the exponent, n, with a growth of the wall temperature, T w. The diffusion vapor layer on the droplet interface and the boundary air layer on the surface of the heated cylinder with a diameter exceeding the droplet's one are formed. A neglect of free convection more than five times underestimates calculation results compared with experimental data. At droplet evaporation it is necessary to take into account convection in a vapor-gas medium and wall roughness.

The dynamics of nucleate boiling of salt solutions at a high heat flux

“…The cooling rate of the heated wall depends both on the geometric parameters of the droplets (the effect of an angle, diameter) and on the wettability [9][10]. The presence of a structured wall leads to an increased heat transfer [11][12]. The lower is the thermal conductivity of the wall material (high thermal inertia), the larger is the wall cooling under the liquid layer.…”

The nucleate boiling in a droplet of aqueous salt solution

“…The evaporation processes are widely used in practice [1][2][3] and are often observed in nature, medicine and biology. Evaporation of a drop and liquids were studied in [4][5][6][7][8][9][10]. In the presence of intense nucleation boiling in a drop, the wetting diameter for distilled water first increases by more than two times, and then both the diameter and the contact angle decrease continuously.…”

Photopolymerization synthesis of polyacrylic acid dispersant with methoxysilicon end groups and its application in a nano‐SiO2 aqueous system

“…SiO 2 nanoparticles have been widely used in the fields of ceramics, cements, coatings, pigments, drug carriers and rubber because of their superior mechanical properties, optical properties, electrical properties and thermodynamic properties . However, they easily aggregate due to the large specific surface area and rich surface hydroxyl groups, which results in their uneven dispersion in systems and then affects their use .…”

“…nanoparticles have been widely used in the fields of ceramics, cements, coatings, pigments, drug carriers and rubber because of their superior mechanical properties, optical properties, electrical properties and thermodynamic properties. [1][2][3][4][5] However, they easily aggregate due to the large specific surface area and rich surface hydroxyl groups, which results in their uneven dispersion in systems and then affects their use. 6,7 In order to improve the dispersity and stability of SiO 2 nanoparticles, methods of adding surfactant or grafting silane coupling agent or polymer on the surface of the particles are usually used.…”