scholarly journals Unsteady heat transfer enhancement in Williamson fluid in Darcy-Forchheimer porous medium under non-Fourier condition of heat flux

2021 ◽  
pp. 101647
Author(s):  
M. Nawaz ◽  
M. Adil Sadiq
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Porous Medium ◽  
Heat Transfer Enhancement ◽  
Transfer Enhancement ◽  
Unsteady Heat Transfer ◽  
Williamson Fluid

scholarly journals Heat transfer enhancement during condensation of water steam on inclined pipe

2021 ◽  
Vol 2039 (1) ◽  
pp. 012031
Author(s):  
S Z Sapozhnikov ◽  
V Yu Mityakov ◽  
A V Mityakov ◽  
A Yu Babich ◽  
E R Zainullina
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Enhancement ◽  
Unit Area ◽  
Experimental Results ◽  
Transfer Enhancement ◽  
Water Steam ◽  
Saturated Water ◽  
Informative Content ◽  
Inclined Pipe

Abstract This paper presents experimental study of heat transfer during film condensation of saturated water steam on the outer surface of the inclined pipe by gradient heatmetry. Heat flux per unit area was measured by gradient heat flux sensors made of a single-crystal bismuth. The experimental results are presented in the graphs of heat flux per unit area dependence on time and azimuthal angle. The highest average heat transfer coefficient during condensation of α = 6.94 kW/(m2 • K) was observed when the pipe was inclined at the angle of ψ = 20 °. This value exceeds one obtained on a vertical pipe by 14.9 %. Heat transfer enhancement during condensation of saturated water steam on inclined pipe is associated with changes in condensate film flow. Another part of experiments was made by simultaneously using of gradient heatmetry and condensate flow visualization. Experimental results confirmed the applicability and high informative content of proposed comprehensive method. Comprehensive study of heat transfer during condensation confirmed that heat flux per unit area pulsations may be explained by the formation of individual drops, their coalescence, and drainage from the sensor surface.

Heat transfer enhancement and migration of ferrofluid due to electric force inside a porous medium with complex geometry

2019 ◽  
Vol 94 (11) ◽  
pp. 115218 ◽  
Author(s):  
Dat D Vo ◽  
S Saleem ◽  
A A Alderremy ◽  
Truong Khang Nguyen ◽  
S Nadeem ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Heat Transfer Enhancement ◽  
Complex Geometry ◽  
Electric Force ◽  
Transfer Enhancement ◽  
And Migration

Numerical Study of the Effects of Different Buoyancy Models on Supercritical Flow and Heat Transfer

2013 ◽  
Author(s):  
X. Y. Xu ◽  
T. Ma ◽  
M. Zeng ◽  
Q. W. Wang
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Enhancement ◽  
Wall Temperature ◽  
Mass Flux ◽  
Wall Heat Flux ◽  
Turbulent Heat ◽  
Transfer Enhancement ◽  
Temperature Prediction ◽  
Flow And Heat Transfer

Due to the dramatic changes in physical properties, the flow and heat transfer in supercritical fluid are significantly affected by buoyancy effects, especially when the ratio of inlet mass flux and wall heat flux is relatively small. In this study, the heat transfer of supercritical water in uniformly heated vertical tube is numerically investigated with different buoyancy models which are based on different calculation methods of the turbulent heat flux. The applicabilities of these buoyancy models are analyzed both in heat transfer enhancement and deterioration conditions. The simulation results show that these buoyancy models make few differences and give good wall temperature prediction in heat transfer enhancement condition when the ratio of inlet mass flux and wall heat flux is very small. With the increase of wall heat flux, the accuracy of wall temperature prediction reduces, and the differences between these buoyancy models become larger. No buoyancy model can currently make accurate wall temperature prediction in deterioration condition in this study.

scholarly journals Investigation of Fin Spacing for Heat Transfer Enhancement in Cross Flow Over Tubes Between Two Parallel Plates

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Ahmad Nurye Oumer ◽  
Amer Farhan Alias
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Exchanger ◽  
Heat Transfer Enhancement ◽  
Parallel Plates ◽  
Transfer Enhancement ◽  
Tube Heat Exchanger ◽  
Finned Tube Heat Exchanger ◽  
Different Types ◽  
Fin Spacing

This research explains the investigation of fin spacing for heat transfer enhancement in the finned tube heat exchanger. The objective of this paper is to recommend the optimum fin spacing for heat transfer enhancement. Three different types of tube and spacing are identified through the simulation from Ansys software. The data between simulation using Ansys Fluent and published literature were being compared. Graph of total pressure, Nusselt number and total temperature have been plotted to make the comparison. Result obtained showed that were a bigger agreement between the simulation and published literature for both types of the tube which are circular and elliptic. From the analysis, there were considered two types of arrangement for the different types of tube. From that, the aligned arrangement is the best for heat transfer enhancement compared to the staggered. For the effect of spacing, there was three spacing which is 1.7 mm, 1.8 mm, and 2.0 mm spacing with velocity and the total heat flux is set to be constant (v =1.4 m/s; q = 500 W/m2). For the circular tube, it can be seen that the wider of the fin spacing gave the best heat transfer enhancement in the heat exchanger. Different from the circular which is 1.8 mm spacing is the best for heat transfer enhancement. Other types of tube are a flat surface which is comparing with the variations of Nu vs Re with different heat flux. Then, the result showed that as the Re is increased the Nu will also increase. In the other side, it is recommended for future work to do the real model dimension followed to import to the Ansys instead of assuming the model is symmetrical.

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