The Role of Delta Winglet Inclination Angle on Heat Transfer Enhancement

2021 ◽  
pp. 155-175
Author(s):  
Junguo Wang ◽  
Yang Yang ◽  
David S.-K. Ting ◽  
Steve Ray
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Inclination Angle ◽  
Transfer Enhancement ◽  
Delta Winglet

CFD Simulations of Flow and Heat Transfer in a Zigzag Channel With Flow Pulsation

2010 ◽  
Author(s):  
Bolaji O. Olayiwola ◽  
Gerhard Schaldach ◽  
Peter Walzel
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Transfer Enhancement ◽  
Steady Flow ◽  
Inclination Angle ◽  
Oscillation Amplitude ◽  
Fluid Mixing ◽  
Transfer Enhancement ◽  
Flow And Heat Transfer ◽  
Flow Through

Heat transfer enhancement by pulsating flow in a zigzag channel has been numerically studied using a commercial CFD software for the ranges of laminar flow 0 < Re < 550. The influence of inclination angle α of the zigzag channel and oscillation parameters is investigated. The amplitude of the pulsatile flow was varied between 0.5 mm and 4 mm. The frequency f ranges between 0.5 Hz and 5.5 Hz. For steady flow, fluid mixing is promoted by self induced fluctuation due to the instability of the flow. The Reynolds number Re for the occurrence of significant eddy decreases with increase of the inclination angle of the channel. Superposition of oscillation additionally promotes further fluid mixing by the propagation of different scales of vortices. In comparison to straight channels, significant heat transfer in the laminar regime is possible using a zigzag channel with inclination angle greater than 15°. Further intensification of the heat transfer is possible with superposition of oscillation on the main flow through the channel. However, the heat transfer enhancement due to imposed oscillation is found to increase with decreasing Reynolds number. The effect of the imposed oscillation yields heat transfer enhancement E of up to 1.41 when compared with steady flow in zigzag channel at Reynolds number Re = 107, frequency f = 2.17 Hz and oscillation amplitude A = 1mm using a zigzag channel with an inclination angle α = 15°. Further heat transfer enhancement E of up to 1.80 at the same flow and oscillation conditions is possible with a zigzag channel having inclination angle α = 45°. The influence of oscillation frequency on the heat transfer enhancement E becomes significant as soon as the Womersley number W > 41.32. The effect of superposition of oscillation is not significant using a zigzag channel with inclination angle α = 60°. When the oscillation amplitude is increased up to 4 mm at Reynolds number Re = 107, frequency f = 2.17 Hz and inclination angle α = 45°, the heat transfer enhancement E of about 3.3 is obtained.

Role of porous metal foam on the heat transfer enhancement for a thermal energy storage tube

2019 ◽  
Vol 239 ◽  
pp. 142-156 ◽  
Author(s):  
Xiaohu Yang ◽  
Jiabang Yu ◽  
Zengxu Guo ◽  
Liwen Jin ◽  
Ya-Ling He
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Heat Transfer Enhancement ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Metal Foam ◽  
Porous Metal ◽  
Transfer Enhancement

Heat transfer enhancement in a tube using delta-winglet twisted tape inserts

2010 ◽  
Vol 30 (4) ◽  
pp. 310-318 ◽  
Author(s):  
S. Eiamsa-ard ◽  
K. Wongcharee ◽  
P. Eiamsa-ard ◽  
C. Thianpong
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Twisted Tape ◽  
Transfer Enhancement ◽  
Delta Winglet
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