Heat transfer enhancement by helically twisted tapes inducing co- and counter-swirl flows

2013 ◽  
Vol 46 ◽  
pp. 67-73 ◽  
Author(s):  
K. Nanan ◽  
K. Yongsiri ◽  
K. Wongcharee ◽  
C. Thianpong ◽  
S. Eiamsa-ard
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Transfer Enhancement ◽  
Twisted Tapes ◽  
Swirl Flows

Experimental Investigation of Heat Transfer Enhancement Using Straight Flat Baffles

2020 ◽  
Vol 12 (2) ◽  
Author(s):  
K.D. Jaganathan ◽  
M. Sivasubramanian
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Energy Transport ◽  
Low Cost ◽  
Reynolds Numbers ◽  
Fundamental Principle ◽  
Transfer Enhancement ◽  
Heat Transfer Augmentation ◽  
Directional Flow ◽  
Swirl Flows

Heat transfer augmentation finds its significance in many uses such as air conditioning, heat exchanger and refrigeration structures. On heat transfer augmentation many researchers conducted experimental and numerical to develop various techniques and methods. Heat transfer enhancement techniques are used to nurture the heat transfer rate without disturbing the complete performance of the system. The energy transport is considered enhanced if the flow is agitated and mixed well. This is the fundamental principle in the development of enhancement techniques that generate swirl flows. Nowadays, baffle inserts have widely been applied for improving the convective heat transfer in various applications due to their effectiveness, low cost and easy setting up. In this experiment an array of straight flat baffles was mounted transversely to the direction of air flow in a rectangular cross-sectioned duct and experiment was conducted for different Reynolds numbers. It is proposed to conduct the investigation to evaluate the influence of the presence of straight flat baffles on the flow path. It is observed experimentally that the straight flat baffles influence greater rate of heat transfer than that of the channel without baffles. The flow visualization for various Reynolds numbers also reports the significance of the presence of straight flat baffles in transverse directional flow.

scholarly journals Heat Transfer Enhancement by Using Different Types of Inserts

2014 ◽  
Vol 6 ◽  
pp. 250354 ◽  
Author(s):  
S. Tabatabaeikia ◽  
H. A. Mohammed ◽  
N. Nik-Ghazali ◽  
B. Shahizare
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Enhancement ◽  
Heat Exchangers ◽  
Low Cost ◽  
Twisted Tape ◽  
Transfer Enhancement ◽  
Thermal Systems ◽  
Twisted Tapes ◽  
High Efficient

Heat transfer enhancement has been always a significantly interesting topic in order to develop high efficient, low cost, light weight, and small heat exchangers. The energy cost and environmental issue are also encouraging researchers to achieve better performance than the existing designs. Two of the most effective ways to achieve higher heat transfer rate in heat exchangers are using different kinds of inserts and modifying the heat exchanger tubes. There are different kinds of inserts employed in the heat exchanger tubes such as helical/twisted tapes, coiled wires, ribs/fins/baffles, and winglets. This paper presents an overview about the early studies on the improvement of the performance of thermal systems by using different kinds of inserts. Louvered strip insert had better function in backward flow compared to forward one. Modifying the shape of twisted tapes led to a higher efficiency in most of the cases excpet for perforated twisted tape and notched twisted tape. Combination of various inserts and tube with artificial roughness provided promising results. In case of using various propeller types, heat transfer enhancement was dependent on higher number of blades and blade angle and lower pitch ratio.

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