非对称纳米通道内流体流动与传热的分子动力学

发布时间：2019-05-06 20:12

【摘要】：采用分子动力学方法研究了流体在非对称浸润性粗糙纳米通道内的流动与传热过程,分析了两侧壁面浸润性不对称对流体速度滑移和温度阶跃的影响,以及非对称浸润性组合对流体内部热量传递的影响.研究结果表明,纳米通道主流区域的流体速度在外力作用下呈抛物线分布,但是纳米通道上下壁面浸润性不对称导致速度分布不呈中心对称,同时通道壁面的纳米结构也会限制流体的流动.流体在流动过程中产生黏性耗散,使流体温度升高.增强冷壁面的疏水性对近热壁面区域的流体速度几乎没有影响,滑移速度和滑移长度基本不变,始终为锁定边界,但是会导致近冷壁面区域的流体速度逐渐增大,对应的滑移速度和滑移长度随之增大.此时,近冷壁面区域的流体温度逐渐超过近热壁面区域的流体温度,流体出现反转温度分布,流体内部热流逆向传递.随着两侧壁面浸润性不对称程度增加,流体反转温度分布更加明显.
[Abstract]:The flow and heat transfer processes of fluid in asymmetric saturated rough nano-channels were studied by molecular dynamics method. The effects of asymmetric wettability on fluid velocity slip and temperature step on both sides of the wall were analyzed. And the influence of asymmetrical wettability combination on heat transfer in fluid. The results show that the velocity distribution in the mainstream region of the nano-channel is parabola under the action of external force, but the asymmetry of the wettability between the upper and lower walls of the nano-channel leads to the dissymmetry of the velocity distribution. At the same time, the nanostructure of the channel wall will also restrict the flow of the fluid. The viscosity and dissipation of the fluid in the process of flow cause the temperature of the fluid to rise. The hydrophobicity of the enhanced cold wall has little effect on the fluid velocity in the near-hot wall region. The slip velocity and slip length are almost unchanged and are always locked boundary, but the fluid velocity in the near-cold wall region will increase gradually. The corresponding slip velocity and slip length increase accordingly. At the same time, the fluid temperature in the near-cold wall region is gradually higher than that in the near-hot wall region, and the temperature distribution of the fluid reverses, and the heat transfer inside the fluid is reversed. With the increase of the saturation asymmetry on both sides of the wall, the temperature distribution of fluid inversion is more obvious.
【作者单位】：华北电力大学低品位能源多相流与传热北京市重点实验室;
【基金】：国家自然科学基金(批准号:51436004)资助的课题~~
【分类号】：O35

【相似文献】