Experimental evaluation of thermal performance in a circular tube with Y-branch insert

2019 ◽  
Vol 106 ◽  
pp. 15-21 ◽  
Author(s):  
Shufeng Huang ◽  
Hanping Chen ◽  
Xiaoxia Zhang ◽  
Zhenping Wan ◽  
Yong Tang
Keyword(s):  
Thermal Performance ◽  
Experimental Evaluation ◽  
Circular Tube

scholarly journals Experimental study on turbulent convective heat transfer, pressure drop, and thermal performance characterization of ZnO/water nanofluid flow in a circular tube

2014 ◽  
Vol 18 (4) ◽  
pp. 1315-1326 ◽  
Author(s):  
Ahmad Sajadi ◽  
Seyed Sadati ◽  
Masoud Nourimotlagh ◽  
Omid Pakbaz ◽  
Dariush Ashtiani ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Thermal Performance ◽  
Base Fluid ◽  
Circular Tube ◽  
Turbulent Regime ◽  
Nanofluid Flow ◽  
Volume Fractions

In this experimental study heat transfer and pressure drop behavior of ZnO/water nanofluid flow inside a circular tube with constant wall temperature condition is investigated where the volume fractions of nanoparticles in the base fluid are 1% and 2%. The experiments? Reynolds numbers ranged roughly from 5000 to 30000. The experimental measurements have been carried out in the fully-developed turbulent regime. The results indicated that heat transfer coefficient increases by 11% and 18% with increasing volume fractions of nanoparticles respectively to 1% and 2% vol. The measurements also showed that the pressure drop of nanofluids were respectively 45% and145% higher than that of the base fluid for volume fractions of 1% and 2% of nanoparticles. However experimental results revealed that overall thermal performance of nanofluid is higher than that of pure water by up to 16% for 2% vol. nanofluid. Also experimental results proved that existing correlations can accurately estimate nanofluids convective heat transfer coefficient and friction factor in turbulent regime, provided that thermal conductivity, heat capacity, and viscosity of the nanofluids are used in calculating the Reynolds, Prandtl, and Nusselt numbers.

Heat Transfer Augmentation and Flow Visualization With Delta Winglets in a Tube: A Numerical Approach

2020 ◽  
Author(s):  
Md. Islam ◽  
Liang Guangda ◽  
Md. Mahbub Alam
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Thermal Performance ◽  
Performance Enhancement ◽  
Swirling Flow ◽  
Circular Tube ◽  
Vortex Generator ◽  
Attack Angle ◽  
Maximum Enhancement ◽  
Longitudinal Vortices

Abstract In this research, heat transfer and pressure penalty from a circular tube with delta winglets insert are numerically investigated through Computational Fluid Dynamics (CFD) methodology. Numerical analysis with and without vortex generators (VGs) insert in a tube are done for a turbulent air flow, Reynolds number ranging from 6000 to 33000, under constant heat flux condition on the circular tube model surface. In our current research, we employed the shear stress transport (SST) k-omega model. The Nusselt number and friction factor results show the influence of the VGs insert on thermal performance. Effects of different winglet attack angles and blockage ratios on thermal performance enhancement were examined. Thermal performance is enhanced 5.1–30.7% using winglets in a tube. It is observed that small blockage ratio, B = 0.1 performed better than its counterpart of 0.2 and 0.3 for all the Reynolds number and for the same attack angle. The attack angle β = 15° and 30° showed better thermal performance enhancement at lower Re while at higher Re, β = 15° showed better performance. The maximum enhancement obtained for β = 30° and B = 0.1. Winglet vortex generator could create swirling flow when attack angle is 0 or 15°. When attack angle is increased, both swirling flow and longitudinal vortices appeared. At attack angle of 45°, large longitudinal vortices was found.

Thermal performance of skin-type, hot-wall condensers, Part I: Component-level modeling and experimental evaluation

2020 ◽  
Vol 110 ◽  
pp. 231-238 ◽  
Author(s):  
Rodolfo S. Espíndola ◽  
Fernando T. Knabben ◽  
Cláudio Melo ◽  
Christian J.L. Hermes
Keyword(s):  
Thermal Performance ◽  
Experimental Evaluation ◽  
Skin Type ◽  
Component Level

Heat Transfer in Round Tube with Rectangular-Winglet Vortex Generators

2014 ◽  
Vol 931-932 ◽  
pp. 1173-1177
Author(s):  
Sompol Skullong ◽  
Pongjet Promvonge
Keyword(s):  
Heat Transfer ◽  
Friction Factor ◽  
Thermal Performance ◽  
Circular Tube ◽  
Convection Heat Transfer ◽  
Test Tube ◽  
Tube Diameter ◽  
Vortex Generators ◽  
Longitudinal Vortex ◽  
The One

Effect of 30° rectangular-winglet vortex generators (WVGs) mounted in the central core of a circular tube on convection heat transfer and friction loss is experimentally investigated in the present work. The rectangular-WVGs with two different winglet-height to tube-diameter ratios (called blockage ratio, BR = b/D = 0.1 and 0.2) and three winglet-pitch to tube-diameter ratios (PR=P/D=0.5, 1.0, and 1.5) are introduced. In the experiment, air at ambient condition is passed through the uniform heat-fluxed circular tube for Reynolds numbers (Re) in a range of 500024,000. The use of WVGs is to generate longitudinal vortex flows in the tube. The experimental results of heat transfer and pressure loss presented in terms of Nusselt number and friction factor are compared between the inserted and the smooth tubes. It is found that the BR and PR provide a significant effect on the thermal performance of the test tube. The results reveal that at smaller PR, the WVG with BR=0.2 provides the highest heat transfer and friction factor but the one with BR=0.2, PR=1.5 yields the best thermal performance.

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