Numerical studies on heat transfer and friction factor characteristics of a tube fitted with helical screw-tape without core-rod inserts
Numerical studies on heat transfer and friction factor characteristics of a tube fitted with helical screw-tape without core-rod inserts
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无芯棒嵌件螺旋带管传热和摩擦系数特性的数值研究
DOI：
10.1016/j.ijheatmasstransfer.2013.01.041
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发表时间：
2013-05
影响因子：
5.2
通讯作者：
Liu W
中科院分区：
文献类型：
--
作者：
Zhang X Y;Liu Z C;Liu W
提出了不同于管边界流强化传热的管芯流强化传热原理，以提高管壁温度均匀性和减小流动阻力。在200 ~ 500 L/h的不同进口流量范围内，对四种不同宽度（W=7.5mm、12 mm、15 mm和20 mm）的螺旋带插入件进行了实验研究。采用数值模拟方法，对传热和流体流动进行了三维湍流分析。模拟结果表明，在管程温度不变的情况下，不同宽度的螺旋带使光管的平均总传热系数提高了212 ~ 351%，摩擦因数提高了33%~ 1020%。不同宽度的螺旋带插入物的PEC值在1.58和2.35之间变化。通过物理量协同分析，探讨了强化传热的机理。计算了协同角α、β、γ、θ和η，数值结果验证了对流换热流场中流体质点物理量之间的协同规律，可指导更好的换热单元和高效换热器的优化设计。并利用熵产分析方法对如何获得最佳螺旋带进行了分析。
The principle of heat transfer enhancement in the core flow of tube has been proposed to improve the temperature uniformity and reduce flow resistance, which is different from that of heat transfer enhancement in the boundary flow of tube. Helical screw-tape inserts with four different widths (w=7.5mm, 12mm, 15mm and 20mm) have been investigated for different inlet volume-flow rates ranging from 200L/h to 500L/h. A three-dimensional turbulence analysis of heat transfer and fluid flow is performed by numerical simulation. The simulation results show that the average overall heat transfer coefficients in circular plain tubes are enhanced with helical screw-tape of different widths by as much as 212∼351% at a constant tube-side temperature and the friction factor are enhanced by as much as 33% to 1020%. The PEC value of the helical screw-tape inserts of different width varies between 1.58 and 2.35. Physical quantity synergy analysis is performed to investigate the mechanism of heat transfer enhancement. The synergy angles α, β, γ, θ and η are calculated, and the numerical results verify the synergy regulation among physical quantities of fluid particle in the flow field of convective heat transfer, which can guide the optimum design for better heat transfer units and high-efficiency heat exchangers. Entropy generation analysis is also performed to explain how to get the optimum helical screw-tape.
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DOI：
10.1016/j.ijheatmasstransfer.2009.02.018
发表时间：
2009-09
影响因子：
5.2
作者：
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