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Numerical Simulation of Laminar Forced Convection Through a Passage With Trapezoid Cross Section and Three Walls Heated
WU Shuang-ying, LIU Yu-hong, LI You-rong, LI Long-jian
Abstract622)      PDF (1720KB)(509)      
A numerical method for simulating three-dimensional laminar forced convective heat transfer in a horizontal passage with trapezoid cross section under uniform heat flux condition was presented. The results presented cover structure parameter b/a range of 1/4~4/3, and included angle of bottom side θ range of 60°, 75° and 85°. The developments and distributions of heat transfer and flow fields, and the average Nusselt numbers at different axial cross-sections in the horizontal passage with trapezoid cross section were discussed when three walls of passage were heated and bottom wall was insulated. In addition, the results were compared with those of four walls heated. The results show that the temperature distribution, convection heat transfer performance and the effects of structure parameters for a passage with trapezoid cross section and three walls heated are different from those with four walls heated. 
2010, 23 (2): 76-79.
Numerical Simulation of Thermal-Hydraulic Characteristics Through  a Helical Coiled Tube With Constant Heat Flux for Laminar Flow
WU Shuang-ying, CHEN Su-jun, LI You-rong, LI Long-jian
Abstract367)      PDF (4562KB)(378)      
A numerical method for simulating the developments and distributions of heat transfer and flow fields was proposed. The effects of Reynolds number, curvature ratio, and coil pitch on the average friction factor, average Nusselt number at different axial cross-sections and the total entropy generation rate in a helical coiled tube with uniform heat flux was presented when Reynolds number is 200~1 000, dimensionless pitch 0.1~0.2 and dimensionless curvature ratio 0.1~0.3. The results show that the effect of the secondary flow is enhanced with the increase of turning angle, the maximum velocity perpendicular to axial cross section shifts toward the outer side of helical coiled tube and two Dean roll cells appear with the increase of axial turning angle. Furthermore, the average friction factor, average Nusselt number at different axial cross-sections and the total entropy generation rate present different characteristics when the Reynolds number, curvature ratio and pitch change. Compared with the curvature ratio, the pitch has relatively little influence on convective heat transfer performance and the total entropy generation. In the meantime, the entropy generation caused by viscous flow is much less than that caused by heat transfer and can be neglected.
2008, 21 (3): 83-87.