Applied Energy, Vol.250, 1491-1547, 2019
Energy saving in thermal energy systems using dimpled surface technology - A review on mechanisms and applications
Recently, dimpled surfaces have found great attention due to their abilities in energy management and heat transfer enhancement, low weight, small values of pressure drop penalty, simple fabrication, and small maintenance costs. Many experimental and numerical studies are accomplished to investigate the potentials of dimpled surface technology in energy management of various thermal energy systems. This paper presents a comprehensive review about the developments and current status of this technology employed in different thermal energy systems including heat exchangers, mini/micro energy systems, two-phase flow energy systems, jet impingement cooling systems, and solar thermal energy systems. Moreover, comprehensive discussions concerning the flow structures and heat transfer behaviours in dimpled surfaces and different geometries and arrangements of dimples are provided. Finally, based on current status of studies in this field, some suggestions are suggested for future researches. The results showed that the main reasons for the convective heat transfer improvement achieved by dimples are flow reattachment, flow impingement, and upwash flow at the downstream region of the dimples, while the heat transfer can be reduced due to flow separation and recirculation in the upstream region of the dimples.
Keywords:Dimpled surface technology;Thermal energy systems;Energy management;Heat transfer enhancement;Pressure drop penalty;Geometries and arrangements