scholarly journals Radiation Effects on Turbulent Heat Transfer Characteristics in Vertical Channel

2020 ◽  
Vol 9 (1) ◽  
pp. 2783-2787
Keyword(s):  
Heat Transfer ◽  
Radiation Effects ◽  
Vertical Channel ◽  
Turbulent Heat Transfer ◽  
Discrete Ordinates ◽  
Turbulent Heat ◽  
Governing Equations ◽  
Heat Transfer Characteristics ◽  
Discrete Ordinates Method ◽  
Computational Fluid Dynamics Cfd

In this study we concentrated on the radiative turbulent air to enter into the convective vertical channel. The vertical channel is having two openings at top and the bottom. The radiation is modelled with discrete ordinates method and turbulence is modelled with computational fluid dynamics (CFD) approach using Lambremhorst turbulence model. The governing equations are solved and discretized by using Finite Difference Method (FDM). The parametric study is performed on Assisting and opposing cases by comparing both the cases with the radiation and without radiation in the channel and found that temperature and velocity characteristics have much impact when the channel is involved with radiation

Turbulent heat transfer characteristics of water flow in a rotating pipe

2013 ◽  
Vol 49 (4) ◽  
pp. 469-484 ◽  
Author(s):  
M. Bousbai ◽  
M. Ould-Rouiss ◽  
A. Mazouz ◽  
A. Mataoui
Keyword(s):  
Heat Transfer ◽  
Water Flow ◽  
Turbulent Heat Transfer ◽  
Turbulent Heat ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics

Modeling and Simulations of Deteriorated Turbulent Heat Transfer in Wall-Heated Cylindrical Tube

2019 ◽  
Vol 4 (3) ◽  
Author(s):  
Prasad Vegendla ◽  
Rui Hu
Keyword(s):  
Heat Transfer ◽  
Nuclear Power ◽  
Three Dimensional ◽  
Cylindrical Tube ◽  
Fluid Flows ◽  
Turbulent Heat Transfer ◽  
Wall Region ◽  
Turbulent Heat ◽  
Modeling And Simulations ◽  
Computational Fluid Dynamics Cfd

Abstract This paper discusses the modeling and simulations of deteriorated turbulent heat transfer (DTHT) for a wall-heated fluid flows, which can be observed in gas-cooled nuclear power reactors during pressurized conduction cooldown (PCC) event due to loss of force circulation flow. The DTHT regime is defined as the deterioration of normal turbulent heat transport due to increase of acceleration and buoyancy forces. The computational fluid dynamics (CFD) tools such as Nek5000 and STAR-CCM+ can help to analyze the DTHT phenomena in reactors for efficient thermal-fluid designs. Three-dimensional (3D) CFD nonisothermal modeling and simulations were performed in a wall-heated circular tube. The simulation results were validated with two different CFD tools, Nek5000 and STAR-CCM+, and validated with an experimental data. The predicted bulk temperatures were identical in both CFD tools, as expected. Good agreement between simulated results and measured data were obtained for wall temperatures along the tube axis using Nek5000. In STAR-CCM+, the under-predicted wall temperatures were mainly due to higher turbulence in the wall region. In STAR-CCM+, the predicted DTHT was over 48% at outlet when compared to inlet heat transfer values.

Numerical Simulations on Turbulent Heat Transfer Characteristics of Supercritical Pressure Fluids

2009 ◽  
Author(s):  
Toru Nakatsuka ◽  
Kazuyuki Takase ◽  
Hiroyuki Yoshida ◽  
Takeharu Misawa
Keyword(s):  
Heat Transfer ◽  
Prediction Accuracy ◽  
Experimental Studies ◽  
Supercritical Pressure ◽  
Turbulent Heat Transfer ◽  
High Heat Flux ◽  
Turbulent Heat ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Annular Channels

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.

Simulation of Circular Tubes Fitted with V Cut and Square Cut Rotors

2013 ◽  
Vol 561 ◽  
pp. 547-552
Author(s):  
Peng Jiang ◽  
Hua Yan ◽  
Zhen Zhang ◽  
Yu Mei Ding ◽  
Wei Min Yang
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Turbulent Heat Transfer ◽  
Cfd Modeling ◽  
Turbulent Heat ◽  
Circular Tubes ◽  
Performance Factor ◽  
Thermal Performance Factor ◽  
Computational Fluid Dynamics Cfd ◽  
Good Agreement

This work presents the effect of V cut and square cut rotors in circular tubes for turbulent heat transfer using computational fluid dynamics (CFD) modeling. The computational results are in good agreement with experimental data. The obtained results reveal that the use of square cut rotors leads to higher Nusselt number than use of V cut rotors. The results also show that the heat transfer rate, friction factor and thermal performance factor of rotors with square cut increase with the increase of width (a) and depth (b) of rotors’ cut. Square cut rotors with a=b=3 yields higher mean thermal performance factor than those with other width and depth, a=b=1, 2 and the highest thermal performance factor of square cut rotors at a=b=1, 2, 3 are found to be 2.08, 2.11 and 2.13.

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