Simulation of turbulent heat transfer characteristics in a corrugated tube with five-channel twisted tape inserts

Author(s):  
Pitak Promthaisong ◽  
Withada Jedsadaratanachai ◽  
Varesa Chuwattanakul ◽  
Smith Eiamsa-ard
2013 ◽  
Vol 49 (4) ◽  
pp. 469-484 ◽  
Author(s):  
M. Bousbai ◽  
M. Ould-Rouiss ◽  
A. Mazouz ◽  
A. Mataoui

Author(s):  
Toru Nakatsuka ◽  
Kazuyuki Takase ◽  
Hiroyuki Yoshida ◽  
Takeharu Misawa

As one of next generation nuclear reactors, development of a supercritical pressure water reactor (SCWR) has been performed. In order to design the SCWR, it is necessary to investigate thermal-hydraulic characteristics in the SCWR core precisely. As for those characteristics, many experimental studies have been conducted from the former in each country using circular tubes, annular channels, and the simulated fuel bundles. An objective of this study is to clarify the prediction accuracy of the turbulent heat transfer characteristics in the supercritical pressure fluids for the SCWR design. From the experimental results of the supercritical pressure fluids flowing upward in a vertical circular tube, it was confirmed that the turbulent heat transfer coefficient suddenly decreases under the high heat flux condition. Although many numerical studies have been done in order to confirm the deterioration of turbulent heat transfer in supercritical pressure fluids, it is important to choose a suitable turbulence model to obtain high prediction accuracy. Then, the present study was performed to investigate numerically the effect of turbulent models on the deteriorated turbulent heat transfer.


Author(s):  
Sandip Dutta ◽  
Je-Chin Han ◽  
Yuming Zhang ◽  
C. Pang Lee

Earlier heat transfer studies with orthogonal rotation were conducted mostly on ducts of square cross-section. This paper reports a different cross-section, a triangular duct. Unlike a square cross-section, the triangular shape provides more restriction to the formation of the secondary flows. Moreover, the studied orientation of the right triangular duct avoids formation of symmetric vortex structures in the cross flow plane. This paper presents turbulent heat transfer characteristics of a two-pass smooth walled triangular duct. One pass is for radial outward flow and the other for radial inward flow. With rotation the radial outward and inward flow directions show different surface heat transfer characteristics. Like a square duct, differences between the trailing and the leading Nusselt number ratios for the triangular duct increase with rotation number. However, the rate of change of Nusselt number ratios with rotation number varies for the two duct geometries. Standard k-ε model predictions for a radial outward flow situation show that the Nusselt number ratio variations with Reynolds number are not drastic for the same rotation number.


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