Thermal rectification refers to the phenomenon by which the magnitude of the heat flux in one direction is much larger than that in the opposite direction.In this study,we propose to implement the thermal rectificatio...Thermal rectification refers to the phenomenon by which the magnitude of the heat flux in one direction is much larger than that in the opposite direction.In this study,we propose to implement the thermal rectification phenomenon in an asymmetric solid–liquid–solid sandwiched system with a nano-structured interface.By using the non-equilibrium molecular dynamics simulations,the thermal transport through the solid–liquid–solid system is examined,and the thermal rectification phenomenon can be observed.It is revealed that the thermal rectification effect can be attributed to the significant difference in the interfacial thermal resistance between Cassie and Wenzel states when reversing the temperature bias.In addition,effects of the liquid density,solid–liquid bonding strength and nanostructure size on the thermal rectification are examined.The findings may provide a new way for designs of certain thermal devices.展开更多
The paper presents a new relationship between the three surface tensions on the solid-liquid-vapor interface, γ_(sl)-γ_(sv)+γ_(lv)cosθ=βin order to understand the wetting on the liquid-solid interface in the case...The paper presents a new relationship between the three surface tensions on the solid-liquid-vapor interface, γ_(sl)-γ_(sv)+γ_(lv)cosθ=βin order to understand the wetting on the liquid-solid interface in the case of active adsorption.The authors suggest a new force“apparent active adsorption force”βto take part in the balance at the three interface lines of contact in the solid-liquid-vapor phases,its dimen- sion isβ=Σα_iRT(Γ_i^(sl)-Γ_i^(sv)+Γ_i^(lv)cosθ),and its direction is dependent on the sign of β,whenβis a positive, the direction is agree with surface tension of the sol- id-vapor interface γ and vice versa.展开更多
Dissolutive wetting, i.e., droplet wetting on dissolvable surfaces, is essential for various natural phenomena and industrial applications such as the formation of sinkholes, enhancing shale gas recovery, drug design,...Dissolutive wetting, i.e., droplet wetting on dissolvable surfaces, is essential for various natural phenomena and industrial applications such as the formation of sinkholes, enhancing shale gas recovery, drug design, MEMS, and so on. It is difficult to predict the evolution of concentration field and solid-liquid interface owing to the coupled effects of wetting, diffusion, and convection. This study makes substantial progress by proposing a new theory based on Onsager’s variational principle and finding two modes of solute transport, i.e., shifting and lifting modes. Furthermore, we investigate the influence of wetting and dissolution coupling on the interface shape using a phase diagram. Using our theory, we can predict and inversely predict the interface evolution.展开更多
During solidifications of immiscible alloys,the motion of droplets at the solid/liquid(S/L)interface is gen-erally driven by dragging force,gravity force,repulsion force of interface,and thermal-solutal Marangoni forc...During solidifications of immiscible alloys,the motion of droplets at the solid/liquid(S/L)interface is gen-erally driven by dragging force,gravity force,repulsion force of interface,and thermal-solutal Marangoni force,However,there is few in situ study investigating kinetics behavior to analyze the forces on droplets.The mechanism of droplet motion remains unclear due to the unavailability or uncertainty of the effect of convection and solutal Marangoni force on droplet behavior.In this study,directional solidification of im-miscible Al-Bi alloy was observed via synchrotron radiography,and the horizontal oscillation of droplets at S/L interface was detected for the first time.Forces,especially solutal Marangoni force,were calcu-lated based on the in situ measured radius of droplets and thermal-solutal gradients.The experimental results cannot be reasonably explained by the previous analysis model which neglects melt convection.The non-negligible effect of flow on droplet motion was demonstrated,and the force balance of droplet both vertically and horizontally can be obtained considering a lift force of 6.39 × 10^(-9) N and a modified solute-related parameter dσ/dc of 0.45-0.65 J m^(-2),respectively.展开更多
基金the National Natural Science Foundation of China(Grant No.51976002)the Beijing Nova Program of Science and Technology(Grant No.Z191100001119033)。
文摘Thermal rectification refers to the phenomenon by which the magnitude of the heat flux in one direction is much larger than that in the opposite direction.In this study,we propose to implement the thermal rectification phenomenon in an asymmetric solid–liquid–solid sandwiched system with a nano-structured interface.By using the non-equilibrium molecular dynamics simulations,the thermal transport through the solid–liquid–solid system is examined,and the thermal rectification phenomenon can be observed.It is revealed that the thermal rectification effect can be attributed to the significant difference in the interfacial thermal resistance between Cassie and Wenzel states when reversing the temperature bias.In addition,effects of the liquid density,solid–liquid bonding strength and nanostructure size on the thermal rectification are examined.The findings may provide a new way for designs of certain thermal devices.
文摘The paper presents a new relationship between the three surface tensions on the solid-liquid-vapor interface, γ_(sl)-γ_(sv)+γ_(lv)cosθ=βin order to understand the wetting on the liquid-solid interface in the case of active adsorption.The authors suggest a new force“apparent active adsorption force”βto take part in the balance at the three interface lines of contact in the solid-liquid-vapor phases,its dimen- sion isβ=Σα_iRT(Γ_i^(sl)-Γ_i^(sv)+Γ_i^(lv)cosθ),and its direction is dependent on the sign of β,whenβis a positive, the direction is agree with surface tension of the sol- id-vapor interface γ and vice versa.
基金supported by the National Natural Science Foundation of China(Grant Nos.11722223,11672300,11872363,and 51861145314)the Chinese Academy of Sciences(CAS)Key Research Program of Frontier Sciences(Grant No.QYZDJ-SSW-JSC019)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB22040401)the CAS Interdisciplinary Innovation Team Project
文摘Dissolutive wetting, i.e., droplet wetting on dissolvable surfaces, is essential for various natural phenomena and industrial applications such as the formation of sinkholes, enhancing shale gas recovery, drug design, MEMS, and so on. It is difficult to predict the evolution of concentration field and solid-liquid interface owing to the coupled effects of wetting, diffusion, and convection. This study makes substantial progress by proposing a new theory based on Onsager’s variational principle and finding two modes of solute transport, i.e., shifting and lifting modes. Furthermore, we investigate the influence of wetting and dissolution coupling on the interface shape using a phase diagram. Using our theory, we can predict and inversely predict the interface evolution.
基金National Natural Science Foundation of China(Nos.52271036 and 51971237)Shanghai Pujiang Program(No.21PJD030)。
文摘During solidifications of immiscible alloys,the motion of droplets at the solid/liquid(S/L)interface is gen-erally driven by dragging force,gravity force,repulsion force of interface,and thermal-solutal Marangoni force,However,there is few in situ study investigating kinetics behavior to analyze the forces on droplets.The mechanism of droplet motion remains unclear due to the unavailability or uncertainty of the effect of convection and solutal Marangoni force on droplet behavior.In this study,directional solidification of im-miscible Al-Bi alloy was observed via synchrotron radiography,and the horizontal oscillation of droplets at S/L interface was detected for the first time.Forces,especially solutal Marangoni force,were calcu-lated based on the in situ measured radius of droplets and thermal-solutal gradients.The experimental results cannot be reasonably explained by the previous analysis model which neglects melt convection.The non-negligible effect of flow on droplet motion was demonstrated,and the force balance of droplet both vertically and horizontally can be obtained considering a lift force of 6.39 × 10^(-9) N and a modified solute-related parameter dσ/dc of 0.45-0.65 J m^(-2),respectively.
