Numerical evaluation of a heat exchanger with inline tubes of different size for reduced fouling rates
Numerical evaluation of a heat exchanger with inline tubes of different size for reduced fouling rates
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DOI：
10.1016/j.ijheatmasstransfer.2012.05.020
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发表时间：
2012-09
影响因子：
5.2
通讯作者：
Sofia G. Mavridou;D. Bouris
中科院分区：
文献类型：
--
作者：
Sofia G. Mavridou;D. Bouris
本文描述了一种新型错流管束换热器的数值评估，该换热器将不同直径的管以串联方式组合在一起，目的是降低气体侧颗粒污垢率，同时保持可接受的传热和压降性能水平。比较了三种布置：具有相同直径的圆柱体的常见直列管束热交换器和由交替放置的圆柱体组成的另两种布置，其直径比为 d/D=0.5，具有两种不同的横向间距。进行数值计算是为了研究含有悬浮灰颗粒的烟气的传热、压降和结垢率。交替的管尺寸实现了对涡流脱落机制的抑制，该机制先前已被证明可以增强下游颗粒沉积。结果表明，与标准布置相比，以最大横向间距放置不等圆柱的管束可显着（~30%）降低颗粒沉积率，而不会牺牲可接受的单位体积传热值和低压降。
This paper describes the numerical evaluation of a novel cross flow tube bundle heat exchanger that combines tubes of different diameter in an inline arrangement for the purpose of reducing gas side particulate fouling rates while preserving acceptable levels of heat transfer and pressure drop performance. Three arrangements are compared: a common inline tube bundle heat exchanger with cylinders of equal diameter and two other arrangements that consist of alternately placed cylinders with a diameter ratio of d/D=0.5, at two different transverse spacings. Numerical calculations are performed in order to study heat transfer, pressure drop and fouling rates from flue gases with suspended ash particles. The alternating tube sizes achieve a suppression of the vortex shedding mechanism that has previously been shown to enhance downstream particle deposition. Results show that, compared to the standard arrangement, the tube bundle with unequal cylinders placed at the largest transverse spacing achieves a significant (∼30%) reduction in particle deposition rate without sacrificing acceptable values of heat transfer per unit volume and low pressure drop.