Open AccessHeat transfer at boiling on a vertical modified surface
Author(s) -
А. Н. Павленко,
В. Е. Жуков,
Ekaterina Slesareva
Publication year - 2020
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1677/1/012092
Subject(s) - heat transfer coefficient , heat transfer , nucleate boiling , materials science , heat flux , critical heat flux , thermodynamics , boiling , brass , freon , fin , composite material , copper , metallurgy , physics
Modification of heat transfer surface through additive technologies (3D printing) is a very promising direction, since it allows organizing surface structures of any complexity with high reproducibility of parameters. This paper presents investigation results on heat transfer at boiling of freon R 21 on a flat, vertically oriented brass surface modified with a copper coating using 3D printing. The heat-transfer surface is modified using 0.5 mm thick and 4 mm wide 3D-printed plates. The plates are made of copper spherical granules with an average diameter of 50 μm by laser welding of granules. The plates are fixed on the heat transfer surface by spot soldering. The experiments are carried out under conditions of large volume at a pressure of 0.18 - 0.21 MPa, which correspond to equilibrium temperatures of 25 - 30°C. The heat flux density varies in the range of 700 - 410000 W/m 2 . Experiments are carried out on the heat transfer surface before modification under the same conditions, but the surface is oriented horizontally. The experimental data show that for a modified heat transfer surface in the range of heat flux density from 1.8·10 4 to 3·10 5 W/m 2 , the heat transfer coefficient changes little and is approximately equal to 1·10 4 W/m 2 K. In the range of heat flux density less than 2·10 5 W/m 2 , the value of heat transfer coefficient on a modified heat transfer surface is up to 4 times greater than on a smooth horizontally oriented heat transfer surface without coating.