scholarly journals Enhanced Heat Transfer by Oil/Multi-Walled Carbon Nano-Tubes Nanofluid

2021 ◽  
Vol 45 (2) ◽  
pp. 93-103
Author(s):  
Abdelhakim Boursas ◽  
Mohamed Salmi ◽  
Giulio Lorenzini ◽  
Hijaz Ahmad ◽  
Younes Menni ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Friction Coefficient ◽  
Enhanced Heat Transfer ◽  
Flow And Heat Transfer ◽  
Turbulence Effect ◽  
Carbon Nano Tubes ◽  
The Subject ◽  
Different Shapes ◽  
Nanometer Particles

The subject of the study is mainly based on thermal reinforcement by an oily fluid containing nanometer particles of carbon. The study is carried out by the presence of discontinuous bars in two different shapes, i.e. flat and V, inside a horizontal heat exchanger. The study relies on simulations in thermal and dynamic terms from the literature. The turbulence effect is diagnosed by applying the k-ε model, while the flow hydrothermal transport relationships are modeled based on the finite volume technique. Both the flow and heat-transfer aspects of all channel regions are studied and analyzed. The new heat-exchanger structure has been enhanced in the presence of these discontinuous bars by reducing the friction coefficient and eliminating stations with poor transfer of heat behind these deflectors.

scholarly journals Uncertainties Analysis on the Prediction of Flow and Heat Transfer of Liquid Sodium with CFD Technology

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Zhanwei Liu ◽  
Xinyu Li ◽  
Tenglong Cong ◽  
Rui Zhang ◽  
Lingyun Zheng ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Friction Coefficient ◽  
Liquid Sodium ◽  
Heat Transfer Characteristics ◽  
Backward Facing Step ◽  
Heating Wall ◽  
Transfer Characteristics ◽  
Cfd Models ◽  
Flow And Heat Transfer

The prediction of flow and heat transfer characteristics of liquid sodium with CFD technology is of significant importance for the design and safety analysis of sodium-cooled fast reactor. The accuracies and uncertainties of the CFD models should be evaluated to improve the confidence of the numerical results. In this work, the uncertainties from the turbulent model, boundary conditions, and physical properties for the flow and heat transfer of liquid sodium were evaluated against the experimental data. The results of uncertainty quantization show that the maximum uncertainties of the Nusselt number and friction coefficient occurred in the transition zone from the inlet to the fully developed region in the circular tube, while they occurred near the reattachment point in the backward-facing step. Furthermore, in backward-facing step flow, the maximum uncertainty of temperature migrated from the heating wall to the geometric center of the channel, while the maximum uncertainty of velocity occurred near the vortex zone. The results of sensitivity analysis illustrate that the Nusselt number was negatively correlated with the thermal conductivity and turbulent Prandtl number, while the friction coefficient was positively correlated with the density and Von Karman constant. This work can be a reference to evaluate the accuracy of the standard k-ε model in predicting the flow and heat transfer characteristics of liquid sodium.

scholarly journals Flow and heat transfer performance of plate phase change energy storage heat exchanger

2019 ◽  
Vol 23 (3 Part B) ◽  
pp. 1989-2000
Author(s):  
Ji-Min Zhang ◽  
Shi-Ting Ruan ◽  
Jian-Guang Cao ◽  
Tao Xu
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Heat Exchanger ◽  
Phase Change ◽  
Thermal Control ◽  
Heat Transfer Characteristics ◽  
Liquid Distribution ◽  
Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
Short Time

In the present work, the phase change energy storage heat exchanger in thermal control system of short-time and periodic working satellite payloads is taken as the research object. Under the condition of constant heated power of the satellite payload, the heat transfer characteristics of phase change energy storage heat exchanger are analyzed by numerical simulation and experimental method. The heat exchanger with fin arrays to enhance heat transfer is filled with tetradecane, whose density varies with temperature. The flow field distribution, the solid-liquid distribution, the temperature distribution, and the phase change process in the plate phase change energy storage heat exchanger unit are analyzed. The flow and heat transfer characteristics of heat exchangers under different fluid-flow rates and temperature were investigated.

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