Conjugate heat and mass transfer in membrane-formed channels in all entry regions
Conjugate heat and mass transfer in membrane-formed channels in all entry regions
复制标题
所有入口区域的膜形成通道中的传热和传质共轭
DOI：
10.1016/j.ijheatmasstransfer.2009.11.043
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发表时间：
2010-02-01
影响因子：
5.2
通讯作者：
Pei, Li-Xia
中科院分区：
文献类型：
--
作者：
Zhang, Li-Zhi;Liang, Cai-Hang;Pei, Li-Xia
膜式能量回收空调器（或全热交换器）是新风换气的关键设备。这有助于控制猪流感（H1N1）和SARS等呼吸道疾病。隔板窄通道是基于膜的能量回收蒸发器的常见结构。在实践中，由于压降和噪声的限制，交换器通道长度受到限制。在这些通道中，水力、热力和集中入口区域占总管道长度的很大一部分。然而，以前的研究为了简单起见而忽略了入口问题。无论是水力充分发展，或热或/和集中充分发展的流动假设，这将严重低估设备的性能，该研究提供了一个更准确的方法。流体的流动、传热和传质方程在进入通道时直接求解，即流体流动和传热传质处于同时发展的区域，膜与相邻两个流动被视为共轭问题，共轭传热问题用商用CFD程序求解。然后通过热质类比将共轭传质问题转化为另一个共轭传热问题求解，计算了入口区的Nusselt数和舍伍德数。三个典型的流动安排：并流，逆流和交叉流，对边界条件和随之而来的努塞尔数和舍伍德数的通道的影响进行了评估。(C)2009爱思唯尔有限公司版权所有
Membrane-based energy recovery ventilators (or total heat exchangers) are key equipments to fresh air ventilation. which is helpful for the control of respiratory diseases like Swine flu (H1N1) and SARS. Parallel-plates narrow channels are common structure for membrane-based energy recovery ventilators In practice, the exchanger channel lengths are limited due to the confinement in pressure drops and noises. In these channels, the hydraulically, thermally and concentrationally entry regions account for a large fraction of the total duct length However, previous investigations neglected the entry issues for simplicity. Either hydraulically fully developed, or thermally or/and concentrationally fully developed flow were assumed, which Would underestimate equipments performances seriously This study provides a more accurate methodology. fluid flow, heat and mass transport equations were solved directly is they enter into the channel In other words, both the fluid flow and the heat and mass transport are in simultaneously developing regions The membrane and the two neighboring flows are considered as a conjugate problem The conjugate heat transfer problem is solved with a commercial CFD code. Then the conjugate mass transfer problem is solved by transferring it to another conjugate heat transfer problem by heat mass analogy The Nusselt and Sherwood numbers in the entry regions are calculated. The effects of three typical flow arrangements: cocurrent, counter and cross flow, on the boundary conditions and the consequent Nusselt and Sherwood numbers in the channels are evaluated. (C) 2009 Elsevier Ltd. All rights reserved