Extraordinary boiling enhancement through micro-chimney effects in gradient porous micromeshes for high-power applications

Heat Transfer Enhancement on Multilayer Wire Mesh Coatings and Wire Mesh Coatings Combined with Other Surface Modifications—A Review

“…Besides, the authors of [24] made the first attempt to systematically study the influence of modulated mesh structures on heat transfer, combining meshes with different wire diameters and mesh apertures, which were called later "gradient mesh coatings" [2]. For this purpose, a mesh with a small aperture was placed on the substrate and meshes with a larger aperture were placed above (Table 2), which resulted in a porous structure with expanding vapor escape channels for enhancement of the HTC and CHF.…”

“…Enhancement of boiling and evaporative heat transfer by means of structured surfaces is essential in upgrading the efficiency of both traditional (immersion and film heat exchangers, desalination plants, chemical processing installations, nuclear power plants, etc. [1]) and renewable (e.g., solar power plants [2]) energy systems. In general, enhanced surfaces can be divided into two main categories: surface structures and porous coatings created or placed on heat-generating surfaces [3].…”

“…However, results of experimental studies of the last decade demonstrate that mesh coatings can be a highly effective means to intensify the heat and mass transfer at optimal selection of mesh characteristics and number of coating layers [9], especially in the case of multilayer coatings with larger aperture of upper layers-so called "gradient mesh coatings" [2]) (approximately sevenfold HTC enhancement in both works [9,2])-or in the case of multi-layer mesh coatings at pool boiling on vertical heaters at atmospheric (HTC enhancement up to 10 times) or subatmospheric (HTC enhancement up to 22 times) pressures [5]. Furthermore, not very high in terms of intensification yet promising results were obtained at combination of mesh coatings with other surface treatments: micro-finning [10][11][12], micronanostructuring of etched wires of mesh [13], or filling with micro-nanoparticle powder mixture [14].…”

“…In recent years, the interest in the use of mesh coatings is renewed against the background of the general growth of research on heat transfer enhancement, including the use of passive methods 2 [15][16][17]. This is related, on the one hand, to the increasing requirements to modern heat-exchange devices and, on the other hand, to the development of material-processing technologies and experimental methods [15][16][17], enabling increasingly sophisticated experiments [2,5,13,14] and previously unattainable intensification results [2,5,9].…”

“…To sum up, from about 1975 to the present, the number of publications on the intensification of heat mass transfer by means of wire mesh coatings for different applications, from heat tubes [18], vaporizers [19][20][21][22], and distillation columns [23] to refrigeration of miniature computer modules (IC chips) [7,10,24] and solar photovoltaic cells [2] is not very large, 3 yet it keeps growing. In these works, the mesh material and size, the number of mesh layers, and their mutual arrangement are varied or combination of mesh coating with other modification kinds is applied at various experimental conditions and methods of coating application.…”