Bubble nucleation plays a crucial role in boiling heat transfer and other applications.Traditional experiments struggle to capture its microscopic mechanisms,making molecular dynamics simulations a powerful tool for s...Bubble nucleation plays a crucial role in boiling heat transfer and other applications.Traditional experiments struggle to capture its microscopic mechanisms,making molecular dynamics simulations a powerful tool for such studies.This work uses molecular dynamics simulations to investigate bubble nucleation of water on copper surfaces with sinusoidal groove roughness under varying heat flux and surface wettability.Results show that at the same wettability,higher heat flux leads to higher surface temperatures after the same heating time,promoting bubble nucleation,growth,and departure.Moreover,under constant heat flux,stronger surface hydrophilicity enhances heat transfer from the solid to the liquid,further accelerating the nucleation.This study provides valuable insights into the mechanism of bubble nucleation and offers theoretical guidance for enhancing heat transfer.展开更多
In modern engineering,enhancing boiling heat transfer efficiency is crucial for optimizing energy use and several industrial processes involving different types of materials.This study explores the enhancement of pool...In modern engineering,enhancing boiling heat transfer efficiency is crucial for optimizing energy use and several industrial processes involving different types of materials.This study explores the enhancement of pool boiling heat transfer potentially induced by combining perforated copper particles on a heated surface with a sodium dodecyl sulfate(SDS)surfactant in saturated deionized water.Experiments were conducted at standard atmospheric pressure,with heat flux ranging from 20 to 100 kW/m2.The heating surface,positioned below the layer of freely moving copper beads,allowed the particle layer to shift due to liquid convection and steam nucleation.The study reports on the influence of copper bead diameter(2,3,4,and 5 mm),particle quantity,arrangement,and SDS concentration(20,200,and 500 ppm).It is shown that the combination of 5 mm particles and a 500 ppm SDS concentration can yield a remarkable 139%improvement in heat transfer efficiency.As demonstrated by direct flow visualization,bubble formation occurs primarily in the gaps between the particles and the heated surface,with the presence of SDS reducing bubble size and accelerating bubble detachment.展开更多
基金supported by the National Natural Science Foun-dation of China(Grant No.52176077).
文摘Bubble nucleation plays a crucial role in boiling heat transfer and other applications.Traditional experiments struggle to capture its microscopic mechanisms,making molecular dynamics simulations a powerful tool for such studies.This work uses molecular dynamics simulations to investigate bubble nucleation of water on copper surfaces with sinusoidal groove roughness under varying heat flux and surface wettability.Results show that at the same wettability,higher heat flux leads to higher surface temperatures after the same heating time,promoting bubble nucleation,growth,and departure.Moreover,under constant heat flux,stronger surface hydrophilicity enhances heat transfer from the solid to the liquid,further accelerating the nucleation.This study provides valuable insights into the mechanism of bubble nucleation and offers theoretical guidance for enhancing heat transfer.
基金supported by the National Natural Science Foundation of China(Project No.52166004)the National Key Research and Development Program of China(Project No.2022YFC3902000)+2 种基金the Major Science and Technology Special Project of Yunnan Province(Project Nos.202202AG050007202202AG050002)the Research on the Development of Complete Sets of Technology for Extraction of Aromatic Substances from Tobacco Waste and Its Application,Applied Research-Pyrolysis Process Technology Research(2023QT01).
文摘In modern engineering,enhancing boiling heat transfer efficiency is crucial for optimizing energy use and several industrial processes involving different types of materials.This study explores the enhancement of pool boiling heat transfer potentially induced by combining perforated copper particles on a heated surface with a sodium dodecyl sulfate(SDS)surfactant in saturated deionized water.Experiments were conducted at standard atmospheric pressure,with heat flux ranging from 20 to 100 kW/m2.The heating surface,positioned below the layer of freely moving copper beads,allowed the particle layer to shift due to liquid convection and steam nucleation.The study reports on the influence of copper bead diameter(2,3,4,and 5 mm),particle quantity,arrangement,and SDS concentration(20,200,and 500 ppm).It is shown that the combination of 5 mm particles and a 500 ppm SDS concentration can yield a remarkable 139%improvement in heat transfer efficiency.As demonstrated by direct flow visualization,bubble formation occurs primarily in the gaps between the particles and the heated surface,with the presence of SDS reducing bubble size and accelerating bubble detachment.
