Experimental Studies on Heat Transfer and Friction Factor Through Isothermal Square Duct with Twisted Tape Inserts

2011 ◽  
Vol 1 (1) ◽  
pp. 77
Author(s):  
Suhas Vinaya Patil ◽  
Pinjala Vijay Babu
Keyword(s):  
Heat Transfer ◽  
Friction Factor ◽  
Experimental Studies ◽  
Twisted Tape ◽  
Square Duct

scholarly journals Experimental studies on effect of bonding the twisted tape with pins to the inner surface of the circular tube

2014 ◽  
Vol 18 (4) ◽  
pp. 1273-1283 ◽  
Author(s):  
S. Selvam ◽  
Pr. Thiyagarajan ◽  
S. Suresh
Keyword(s):  
Heat Transfer ◽  
Friction Factor ◽  
Experimental Studies ◽  
Twisted Tape ◽  
Constant Wall Temperature ◽  
Tube Heat Exchanger ◽  
Inner Surface ◽  
Fully Developed Turbulent Flow ◽  
Flow Experiments ◽  
Twist Pitch

Heat transfer and friction factor characteristics are studied for water flowing through the tube in tube heat exchanger for two different configurations, namely,(1) twisted tape with pins (TTP) and (2) twisted tape with pins bonded to the inner surface of the test section (TTPB). Experiments are carried out for different twist pitch to the width of the twisted tape ratios (y/w) for TTP and TTPB. But very few research works have been done based on the above mentioned heat transfer enhancement techniques. This paper presents the effect of twisted tape with pins on the heat transfer for a fully developed turbulent flow. Experiments are conducted by maintaining constant wall temperature. The heat transfer rate and pressure drop is found to be high for TTPB of y/w=3.33 when compared to all other configurations. The empirical correlations developed for different twisted tape with pins results in ?7.28% deviation for Nusselt number and ?7.16% for friction factor.

Experimental Studies and Correlations of Radially Outward and Inward Air-Flow Heat Transfer in a Rotating Square Duct

1996 ◽  
Vol 118 (1) ◽  
pp. 23-30 ◽  
Author(s):  
C. R. Kuo ◽  
G. J. Hwang
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Experimental Studies ◽  
Leading Edge ◽  
Wall Heat Transfer ◽  
Square Duct ◽  
Reinforced Plastic ◽  
Flow Heat ◽  
The Mean ◽  
Heated Length

Experiments were conducted to investigate the convective heat transfer of radially outward and inward air flows in a uniformly heated rotating square duct. The interior duct surfaces, constructed by fiberglass-reinforced plastic, were plated with separated film heaters for distinguishing the local wall heat transfer rate. The duct hydraulic diameter, the actively heated length, and the mean rotation radius are 4, 120, and 180 mm, respectively. In the experiments, the parameters were the throughflow Reynolds number, Re = 1,000∼15,000; the rotation number, Ro = 0∼0.32; and the rotational buoyancy parameter, Ra* = 0∼0.5. For the outward flow the Coriolis-induced cross-stream secondary flow strongly enhanced the heat transfer on the leading edge. But for the radially inward flow the trend was reversed. When the throughflow Reynolds number was increased, the rotating-buoyancy decreased, then increased the heat transfer for the outward flow; however, the rotating-buoyancy always increased the heat transfer for the inward flow. The heat transfer data are correlated for the outward and inward flows for the ranges of parameters under study.

Prediction of Swirl Flow and Heat Transfer through Square Duct with Twisted Tape Insert

2013 ◽  
Vol 284-287 ◽  
pp. 888-893 ◽  
Author(s):  
Ho Keun Kang ◽  
Soo Whan Ahn ◽  
Myung Sung Lee
Keyword(s):  
Heat Transfer ◽  
Turbulent Flows ◽  
Flow Direction ◽  
Swirl Flow ◽  
Hydraulic Diameter ◽  
Twisted Tape ◽  
Square Duct ◽  
Square Channel ◽  
Numerical Predictions ◽  
Commercial Code

Numerical predictions of characteristics of turbulent flows through a square duct (30 30 mm) with twisted tape inserts and with twisted tape inserts plus interrupted ribs are conducted to investigate regionally averaged heat transfer and friction factors by using CFX 11.0 commercial code. The validity of the numerical results is confirmed by measurement. Reynolds numbers are varied between 8,900 and 29,000. A rib height-to-channel hydraulic diameter (e/Dh) of 0.067 and a length-to hydraulic diameter (L/Dh) of 30 are considered. The square ribs are arranged to follow the trace of the twisted tape and along the flow direction defined as axial interrupted ribs. The twisted tape is 0.1 mm thick carbon steel sheet with diameter of 28mm, length of 900mm and 2.5 turns. Each wall of the square channel is composed of the isolated aluminum section. The present study demonstrates that the twisted tape with interrupted ribs provides a greater overall heat transfer performance over the twisted tape with no ribs in the square duct.

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