Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
668071 | International Journal of Thermal Sciences | 2015 | 10 Pages |
Abstract
Heat transfer and friction loss characteristics of a plain tube fitted with double spiral spring (DSS) are investigated by a three dimensional numerical simulation. The outer diameters of the DSS are 9Â mm, 12Â mm, 15Â mm, and 18Â mm, respectively. The simulation results indicate that the fluid in the tube inserted with DSS shows three-dimensional helical flow, and that the circumferential and the radial velocity of fluid near the tube wall are improved. At the same Reynolds number, the average radial and tangential velocities of the DSS tube are significantly higher than those of the plain tube. The Nusselt number increases and the friction factor decreases in tube with DSS insert as the Reynolds number increases. With the increase of the ds/D of DSS, the friction factor becomes higher. The field synergy principle (FSP) and entransy dissipation extremum principle (EDEP) analysis provide a reliable criterion for exploring the mechanism of heat transfer enhancement. The field synergy number of the tube inserted with DSS is much higher than that of plain tube, which indicates effective improvement of flow and heat transfer by inserted DSS. Meanwhile, the value of performance evaluation criterion (PEC) could be up to 1.5.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Fluid Flow and Transfer Processes
Authors
Cancan Zhang, Dingbiao Wang, Youjian Zhu, Yong Han, Jinxing Wu, Xu Peng,