采用非平衡态分子动力学方法研究了纳米尺度下固体壁面润湿性和粗糙元对固液界面换热的影响。固液界面由铂固壁与液体氩接触形成,并在固壁上分布着不同形状的粗糙元,包括三角形、矩形、正弦和随机形状,通过虚拟原子法将两侧固壁恒定于不同温度,通过USHER法使液体密度恒为定值。模拟结果表明:(1)润湿性越小、粗糙元面积比率越大,界面热阻越小,界面换热强度越大;(2)粗糙元形状对界面换热有影响,其中矩形粗糙的强化作用最大;(3)润湿性和粗糙元对液体区热阻影响甚微,所以系统换热性能的改变主要是由于界面热阻的变化所致。
Non-equilibrium molecular dynamics simulation is carried out to study the effects of wettability and nanoscale roughness on heat transfer through the solid-liquid interface. The liquid is Ar and the solid wall is Pt. The roughnesses with different shapes, including triangular, rectangular, sinusoidal and random roughnesses, distribute on the walls. The two walls are kept at different temperature by the phantom method. The USHER algorithm is employed to maintain an identical liquid density. The results show that (1) Both the wettability and the roughness can reduce the interfacial thermal resistance, thus enhancing the heat transfer through the interface by increasing the contact area; (2) The roughness shapes have effects on the heat transfer and the rectangular roughness performs best in enhancing heat transfer; (3) Both of the wettability and roughness have little effects on the film conduction, and the interracial thermal resistance is found to be the key factor that influences heat transfer.