Effects of shear work on non-equilibrium heat transfer characteristics of rarefied gas flows through micro/nanochannels
Effects of shear work on non-equilibrium heat transfer characteristics of rarefied gas flows through micro/nanochannels
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DOI：
10.1016/j.ijheatmasstransfer.2014.11.087
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发表时间：
2015-04-01
影响因子：
5.2
通讯作者：
Akhlaghi, Hassan
中科院分区：
文献类型：
--
作者：
Balaj, Mojtaba;Roohi, Ehsan;Akhlaghi, Hassan
在本文中，研究了恒定壁面热流边界条件下，速度滑移引起的剪切功对压力驱动微纳米通道内非平衡换热的影响。作为我们的仿真工具，我们采用了直接序列蒙特卡罗方法。壁面热流的计算采用“修正迭代”技术。我们研究了稀疏性、性质变化和可压缩性的影响。数值结果表明，壁面剪切应力对微纳米通道的流动行为和换热有重要影响，如热流密度等。分析了冷却过程中出现的逆梯度热流(冷热换热)现象。结果表明，粘性耗散对壁面热流有影响，可以克服壁面热流，即在较低的壁面热流条件下，剪切功可以完全加热流场。还讨论了Nusselt数的奇异性。(C)2014爱思唯尔有限公司。保留所有权利。
In the current work, the effect of shear work due to the velocity slip on the non-equilibrium heat transfer in a pressure driven micro/nanochannel is evaluated under the constant wall heat flux boundary condition. As our simulation tool, the DSMC method is employed. Implementation of the wall heat flux in the DSMC method is performed using the "modified Iterative" technique. We investigate the effects of rarefaction, property variations and compressibility. The numerical results show that shear stress on the walls significantly affects all aspects of the flow behavior and heat transfer through micro/nanochannels such as heat flux rates. We also analyze the counter-gradient heat flow (cold to hot heat transfer) phenomenon appearing at the cooling conditions. It is observed that viscous dissipation affects the heat flux applied to the walls and may overcome the wall heat flux, i.e., in the case of low cooling wall heat flux condition, shear work may completely heat the flow field. Nusselt number singularity is also discussed. (C) 2014 Elsevier Ltd. All rights reserved.