微纳圆柱外气体导热的尺度效应

Scale Effect on Thermal Conductivity of Gas Layer Around a Micro Cylinder

本文通过数值模拟方法(DSMC),对微纳气体在圆柱与方腔壁间导热现象及尺度效应的机理进行了探讨,通过模拟发现了热导率随尺度变大而逐渐变大并趋向于体材料,本文主要探讨了稀薄效应与受限空间对尺度效应的影响,模拟发现圆柱壁面处温度跳跃与受限空间内气体性质的改变是微纳圆柱外气体薄层导热尺度效应的根本原因.

We studied heat conduction in a gas layer around a micro cylinder in a square cavity using the direct simulation Monte Carlo （DSMC） method. The thermal conductivity of gas layer reduces significantly with the decrease of radius of cylinder. We examined possible causes including rarefied gas effect and confined space effect. Our simulations indicate that the temperature jump on wall surfaces and properties changed significantly by the confined space are two dominating factors to the scale effect on the heat conduction of micro gas laver.