Vibration-Assisted Laser Surface Texturing and Electromachining for the Intensification of Boiling Heat Transfer in a Minichannel

Abstract

The paper describes applications of the vibration-assisted laser surface texturing and spark erosion process as methods of modifying properties and structures of metal surfaces. Practical aspects of the use of produced surfaces in the heat exchanger with a minichannel have been described. Compared with smooth surfaces, developed metal surfaces obtained by vibration-assisted laser surface texturing and electromachining show more effective heat transfer. The local heat transfer coefficient for the saturated boiling region obtained for developed surfaces had the values significantly higher than those obtained for the smooth plate at the same heat flux. The experimental results are presented as the heated plate temperature (obtained from infrared thermography) and relationships between the heat transfer coefficient and the distance along the length of the minichannel for the saturated boiling region.

Enhanced Surfaces Used in Research on Flow Boiling Heat Transfer in Minichannels

“…The Hastelloy X and Haynes-230 alloy plates are made mainly of Ni-Cr-Fe-Mo and Ni-Cr-W-Mo alloys, respectively. In addition to excellent high-temperature strength and oxidation resistance [6]. Images of the smooth and enhanced tested surfaces were presented in Fig.…”

“…One of the methods of heat transfer enhancement involves heat transfer surface modification. The modification causes the increase of heat transfer coefficient values through increasing the number of active nucleation sites during flow boiling [1][2][3][4][5][6][7][8][9][10] or pool boiling [10][11][12]. Modified surfaces exhibit reduced surface superheating and improve heat dissipation by increasing the area of heat removal.…”

“…In their previous articles, the authors of this paper reported their findings concerning various enhanced heat transfer surfaces with the flow of various working fluids through rectangular heat exchangers with minichannels. The surfaces studied included laser-textured surfaces with regular recesses [2,7], vibration-assisted laser-textured surfaces [3,4,6], surfaces with irregular recesses obtained in the process of spark erosion [1,2,5,6,10,11], surface with capillary-fibrous structure [1] and powder surfaces produced by sintering or soldering [8,9]. Based on the research results for flow boiling in minichannels, this article discusses the enhanced surfaces used, along with their production methods and effects on heat transfer processes.…”

Impact of Fe powder sintering and soldering in production of porous heating surface on flow boiling heat transfer in minichannels

“…The temperature of the smooth side of the heated plate was measured by infrared camera in the central axially symmetric part of the minichannel. Thermal accuracy of the infrared camera E60 manufactured by FLIR was ± 1 °C or ± 1% within the temperature range of 0÷120°C [11]. It was possible to observe the plate surface through a glass pane using a fast camera.…”

“…One of the solutions is the use of boiling phenomena, the other -using enhanced heated surfaces produced by different methods [1][2][3]. Studies have been conducted on pool boiling [4][5][6], flow boiling [7][8][9][10][11] heat transfer and confined spaces as face seals [12,13]. Primarily passive methods are being developed for use in porous coating applications and in metal surface mechanical processing [14,15].…”