scholarly journals Heat Transfer of Supercritical Fluid Flows and Compressible Flows

10.5772/65931 ◽  
2017 ◽  
Author(s):  
Yu Ito
Keyword(s):  
Heat Transfer ◽  
Supercritical Fluid ◽  
Compressible Flows ◽  
Fluid Flows

A New Correlation for the Turbulent Prandtl Number in Upward Rounded Tubes in Supercritical Fluid Flows

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Mahdi Mohseni ◽  
Majid Bazargan
Keyword(s):  
Heat Transfer ◽  
Prandtl Number ◽  
Supercritical Fluid ◽  
Supercritical Fluids ◽  
Fluid Pressure ◽  
Fluid Flows ◽  
Numerical Code ◽  
Turbulent Prandtl Number ◽  
New Correlation ◽  
Model Predictions

Numerical results show that at supercritical pressures, once the buoyancy force increases, the effect of the turbulent Prandtl number, Prt, on convective heat transfer becomes considerable. This phenomenon has not been adequately addressed in the literature. In this study, the effect of the turbulent Prandtl number on the rate of heat transfer in both enhanced and deteriorated regimes of heat transfer to supercritical fluid flows has been extensively investigated. Having realized that variations of the turbulent Prandtl number can affect the model predictions so greatly, a new correlation to express the changes of Prt with respect to flow conditions in a supercritical environment is developed. Effects of various important parameters such as heat flux, mass flux, and fluid pressure are included in the proposed correlation. This correlation has been modified to be applicable for different supercritical fluids. The comparison with various experimental data shows that by implementing the new correlation of Prt in the numerical code, it is possible to significantly improve the simulation results. Such a correlation seems to be the first one introduced in the literature for a supercritical fluid flow.

Heat Transfer to Power-Law Fluid Flows Through Porous Media

2001 ◽  
Vol 4 (4) ◽  
pp. 10 ◽  
Author(s):  
B. K. Rao
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
Power Law ◽  
Fluid Flows ◽  
Power Law Fluid ◽  
Flows Through Porous Media

Comparison of heat transfer models with databank of supercritical fluid

Kerntechnik ◽  
2018 ◽  
Vol 83 (3) ◽  
pp. 237-240
Author(s):  
M. Zhao ◽  
X. Liu ◽  
A. Badea ◽  
F. Feuerstein ◽  
X. Cheng
Keyword(s):  
Heat Transfer ◽  
Supercritical Fluid ◽  
Transfer Models

Transient Heat Transfer Characteristics of Supercritical Fluid during Rapid Depressurization Process

2018 ◽  
Vol 145 ◽  
pp. 435-443
Author(s):  
Qiaoling Zhang ◽  
Jiahao Cao ◽  
Qincheng Bi ◽  
Zhendong Yang ◽  
Jianguo Yan
Keyword(s):  
Heat Transfer ◽  
Supercritical Fluid ◽  
Transient Heat Transfer ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics

scholarly journals Performance Analysis and Design Optimization of Shell and Tube Heat Exchangers

2021 ◽  
Author(s):  
praveen math
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Pressure Loss ◽  
Fluid Flows ◽  
Hot Water ◽  
Flow Conditions ◽  
Shell Side ◽  
Shell And Tube ◽  
Side Flow

Abstract Shell and Tube heat exchangers are having special importance in boilers, oil coolers, condensers, pre-heaters. They are also widely used in process applications as well as the refrigeration and air conditioning industry. The robustness and medium weighted shape of Shell and Tube heat exchangers make them well suited for high pressure operations. The aim of this study is to experiment, validate and to provide design suggestion to optimize the shell and tube heat exchanger (STHE). The heat exchanger is made of acrylic material with 2 baffles and 7 tubes made of stainless steel. Hot fluid flows inside the tube and cold fluid flows over the tube in the shell. 4 K-type thermocouples were used to read the hot and cold fluids inlet and outlet temperatures. Experiments were carried out for various combinations of hot and cold water flow rates with different hot water inlet temperatures. The flow conditions are limited to the lab size model of the experimental setup. A commercial CFD code was used to study the thermal and hydraulic flow field inside the shell and tubes. CFD methodology is developed to appropriately represent the flow physics and the procedure is validated with the experimental results. Turbulent flow in tube side is observed for all flow conditions, while the shell side has laminar flow except for extreme hot water temperatures. Hence transition k-kl-omega model was used to predict the flow better for transition cases. Realizable k- epsilon model with non-equilibrium wall function was used for turbulent cases. Temperature and velocity profiles are examined in detail and observed that the flow remains almost uniform to the tubes thus limiting heat transfer. Approximately 2/3 rd of the shell side flow does not surround the tubes due to biased flow contributing to reduced overall heat transfer and increased pressure loss. On the basis of these findings an attempt has been made to enhance the heat transfer by inducing turbulence in the shel l side flow. The two baffles were rotated in opposite direction to each other to achieve more circulation in the shell side flow and provide more contact with tube surface. Various positions of the baffles were simulated and studied using CFD analysis and th e results are summarized with respect to heat transfer and pressure loss.

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