Department of Chemical Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, USA.
J Chem Phys. 2012 Aug 28;137(8):081101. doi: 10.1063/1.4749288.
Thermal rectification, the origin of which lies in modifying the thermal resistance in a nonlinear manner, could significantly improve the thermal management of a wide range of nano-devices (both electronic and thermoelectric), thereby improving their efficiencies. Since rectification requires a material to be inhomogeneous, it has been typically associated with solids. However, the structure of solids is relatively difficult to manipulate, which makes the tuning of thermal rectification devices challenging. Since liquids are more amenable to tuning, this could open up new applications for thermal rectification. We use molecular dynamics simulations to demonstrate thermal rectification using liquid water. This is accomplished by creating an inhomogeneous water phase, either by changing the morphology of the surface in contact with the liquid or by imposing an arbitrary external force, which in practice could be through an electric or magnetic field. Our system consists of a bulk fluid that is confined in a reservoir that is bounded by two walls, one hot and the other cold. The interfacial (Kapitza) thermal resistance at the solid-fluid interface and the density gradient of the bulk fluid both influence the magnitude of the thermal rectification. However, we find that the role of the interfacial resistance is more prominent than the application of an external force on the bulk fluid.
热整流，其起源在于以非线性方式改变热阻，可以显著改善各种纳米器件（电子和热电）的热管理，从而提高它们的效率。由于整流需要材料不均匀，因此它通常与固体有关。然而，固体的结构相对难以操纵，这使得热整流器件的调谐具有挑战性。由于液体更容易调谐，这可能为热整流开辟新的应用。我们使用分子动力学模拟来演示使用液态水进行热整流。这是通过创建不均匀的水相来实现的，要么通过改变与液体接触的表面的形态，要么通过施加任意外力来实现，实际上可以通过电场或磁场来实现。我们的系统由一个被限制在由两个壁组成的储层中的体相流体组成，一个是热的，另一个是冷的。固体-流体界面处的界面（卡皮察）热阻和体相流体的密度梯度都影响热整流的幅度。然而，我们发现界面电阻的作用比在体相流体上施加外力更为突出。
