• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>International Journal of Heat and Mass Transfer >The effects of exothermic catalytic reactions upon combined transport of heat and mass in porous microreactors
【24h】

The effects of exothermic catalytic reactions upon combined transport of heat and mass in porous microreactors

机译：放热催化反应对多孔微反应器中热量和质量的联合传输的影响

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Microreactors for chemical synthesis and combustion have already attracted significant attention. Exothermic catalytic activity features heavily in these devices and thus advective-diffusive transport is of key importance in their analyses. Yet, thermal modelling of the heat generated by catalytic reactions on the internal surfaces of porous microreactors has remained as an important unresolved issue. To address this, the diffusion of heat of catalytic reactions into three phases including fluid, porous solid and solid walls is investigated by extending an existing interface model of porous media under local thermal non-equilibrium. This is applied to a microchannel fully filled with a porous material, subject to a heat flux generated by a catalytic layer coated on the porous-wall boundary. The finite wall thickness and viscous dissipation of the flow kinetic energy are considered, and a two-dimensional analytical model is developed, examining the combined heat and mass transfer and thermodynamic irreversibilities of the system. The analytical solution is validated against the existing theoretical studies on simpler configurations as well as a computational model of the microreactor in the limit of very large porosity. In keeping with the recent findings, the wall thickness is shown to strongly influence the heat and mass transport within the system. This remains unchanged when the symmetricity of the microchannel is broken through placing walls of unequal thicknesses, while deviation from local thermal equilibrium is significantly intensified in this case. Importantly, the Nusselt number is shown to have a singular point, which remains fixed under various conditions. (C) 2019 Elsevier Ltd. All rights reserved.
机译：用于化学合成和燃烧的微反应器已经引起了广泛的关注。在这些装置中，放热催化活性具有很大的特征，因此对流-扩散传输在其分析中至关重要。然而，在多孔微反应器的内表面上由催化反应产生的热量的热模型仍然是一个重要的未解决的问题。为了解决这个问题，通过扩展局部热非平衡下多孔介质的现有界面模型，研究了催化反应的热扩散到包括流体，多孔固体和固体壁的三个阶段。这被施加到完全填充有多孔材料的微通道上，该微通道经受由涂覆在多孔壁边界上的催化层产生的热通量。考虑了流动动能的有限壁厚和粘性耗散，并建立了二维分析模型，研究了系统的传热传质和热力学不可逆性。该分析解决方案已针对较简单的配置以及微反应器在非常大的孔隙率范围内的计算模型的现有理论研究进行了验证。与最近的发现一致，壁厚显示出强烈影响系统内的热量和质量传递。当通过放置厚度不相等的壁破坏微通道的对称性时，这保持不变，而在这种情况下，与局部热平衡的偏离会明显加剧。重要的是，努塞尔数显示为具有奇异点，该奇异点在各种条件下均保持不变。 （C）2019 Elsevier Ltd.保留所有权利。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号