粗糙固体表面温度阶跃的分子动力学模拟

Molecular dynamics simulation of temperature jump on rough solid surfaces

建立了粗糙纳通道内液体热传导的分子动力学模型,模拟研究了纳通道内液体的温度分布和液固界面处的温度阶跃现象,获得了液固相互作用强度、表面粗糙高度和壁面刚度对界面处温度阶跃的影响规律.研究结果表明:在固体壁面附近,液体温度偏离了线性分布,液固界面处出现了温度阶跃.与光滑表面相比,粗糙度的存在降低了液固界面处的温度阶跃程度.粗糙高度的增加扩大了液固相互作用面积,延长了近壁面附近的液体分子与固体之间的能量交换时间,强化了液固界面的能量传递,从而使得界面处温度阶跃降低.另外,提高液固相互作用强度或者降低固壁刚度均可使液固界面处温度阶跃程度减小.

The molecular dynamics model is established to simulate the heat conduction of liquid in a rough nanochannel so as to investigate the temperature distribution of liquid in nanochannel and the interfacial temperature jump.The effects of liquid-solid interaction,roughness height and wall stiffness on the temperature jump are analyzed.The results indicate that the temperature profile deviates from the linear fashion in the wall-neighboring region,and the temperature jump is observed at the rough solid surface.Compared with the smooth surface,the presence of the roughness decreases the temperature jump length at the boundary.A larger roughness height increases the contact area between the liquid and the solid,which enhances the energy transfer at liquid-solid interface and hence decreases the temperature jump.In addition,the increase in liquid-solid interaction strength or reduction in wall stiffness leads to a smaller temperature jump length.