scholarly journals Experimental Investigation on Enhancement of Heat Transfer Rate in Heat Exchangers using Plain and Punched Twisted Tape Inserts and Nanofluid Employing Al2O3 Particles

2017 ◽  
Vol 10 (25) ◽  
pp. 1-6
Author(s):  
K. N. Pavan ◽  
S. Suresh ◽  
Madhusudhan ◽  
Sekhar Majumdar ◽  
◽  
...  
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Heat Transfer Rate ◽  
Heat Exchangers ◽  
Transfer Rate ◽  
Twisted Tape ◽  
Enhancement Of Heat Transfer ◽  
Al2o3 Particles

scholarly journals Augmentation of Heat Transfer in a Duct with Rotating Turbulator using Al2o3 Nanofluid

2019 ◽  
Vol 8 (3) ◽  
pp. 3059-3062
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Transfer Enhancement ◽  
Heat Transfer Rate ◽  
Heat Exchangers ◽  
Transfer Rate ◽  
Twisted Tape ◽  
Transfer Enhancement ◽  
Twist Ratio ◽  
Al2o3 Nanofluid

The heat transfer enhancement is one of the essential factors to be considered in the design of heat exchangers. The rate of heat transfer can be enhanced by inserting and modifying the geometric configuration of the turbulators in the tube of heat exchangers. In our present work we conducted the experiment to investigate the rate of heat transfer enhancement in a tubular in a heat exchanger by using rotating twisted tape turbulator of twist ratio 3.27 using water and Al2O3 nanofluid as a testing fluid at the flow rate of 1, 2, and 3 LPM. The range of Reynolds number used is 2000<Re<10000, the heat transfer rate calculated for each case of rotating TTT with the speed of 0 to 300 RPM with the step of 100 RPM. The obtained results are compared between water and Al2O3 nanofluid, with and without rotating TTT. From the comparisons, it was found that the TTT with U-cut and the use of Al2O3 nanofluid gives the better rise in the heat transfer rate of about 39.63%. The augmented rate of heat transfer is due to the more turbulence when the rotating TTT is used and replacing the water with nanofluid as the testing fluid which of high thermal properties.

scholarly journals Enhancement of Heat Transfer in a Rouletted Copper Tube Employing Delta Winglet Twirled Type Insert

2018 ◽  
Vol 3 (5) ◽  
pp. 47
Author(s):  
Mohammad Taukir Hossain ◽  
Nesar Ali ◽  
Muhammad Sadekul Karim
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Copper Tube ◽  
Twisted Tape ◽  
Enhancement Of Heat Transfer ◽  
Plain Tube ◽  
Wire Coil ◽  
Delta Winglet ◽  
Pitch Length

Heat transfer is a process or a system of thermal engineering that concerns the generation, use, conversion, transfer, internal or external molecular formation and exchange of thermal energy (heat) between physical systems. The research work has been experimented for the turbulent flow heat transfer in a tube having delta winglet twisted tape and then separately with water as working fluid. The test section consisted of a circular copper tube of 26.6 mm inner diameter, 900 mm length with five K-type thermocouples. Bulk temperature and pressure drops have been measured. Material of both the delta winglet twisted tape insert was stainless steel. Delta winglet twisted tape insert had a length of 795mm, width of 20mm, thickness of 2mm, pitch length of 120mm, twist ratio of 6 while wire coil insert had the same length as that of delta winglet twisted tape insert, wire diameter of 1mm, mean coil diameter of 22mm and pitch length of 30mm. Heat transfer rate, convective heat transfer coefficient, Nusselt’s number, friction factor and heat transfer efficiency have been calculated to analyze heat transfer performance of circular copper tube fitted with or without inserts in turbulent regimes (4000<Re<15000). Nusselt’s numbers for combination of delta winglet twisted tape and wire coil insert, wire coil insert only, delta winglet twisted tape insert only increased by 1.29 to 1.47, 1.19 to 1.34 and 1.10 to 1.15 times respectively than the plain tube. They increased by 17.95% to 27.61%, 15.97% to 20.20%, 8.90% to 12.02% and average of 21.65%, 17.44%, 8.95% respectively than the plain tube. Heat transfer rates also increased by 1.12 to 1.20, 1.06 to 1.09 and 1.03 to 1.05 times respectively compared to the plain tube. Heat transfer efficiencies increased by 1.36% to 1.62%, 1.24% to 1.47% and 1.14% to 1.34% respectively compared to the plain tube. Friction factors increased by 1.44 to 1.62, 1.34 to 1.43, 1.22 to 1.27 times respectively compared to the plain tube. The delta winglet twisted tape was the best arrangement for the enhancement of heat transfer rate as compared to the other inserts.

Pressure Drop and Heat Transfer Characteristics of Louvered Fin Heat Exchangers

2013 ◽  
Vol 465-466 ◽  
pp. 500-504 ◽  
Author(s):  
Shahrin Hisham Amirnordin ◽  
Hissein Didane Djamal ◽  
Mohd Norani Mansor ◽  
Amir Khalid ◽  
Md Seri Suzairin ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Transfer Rate ◽  
Heat Exchangers ◽  
Transfer Rate ◽  
Three Dimensional ◽  
Considerable Effect ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Louvered Fin

This paper presents the effect of the changes in fin geometry on pressure drop and heat transfer characteristics of louvered fin heat exchanger numerically. Three dimensional simulation using ANSYS Fluent have been conducted for six different configurations at Reynolds number ranging from 200 to 1000 based on louver pitch. The performance of this system has been evaluated by calculating pressure drop and heat transfer coefficient. The result shows that, the fin pitch and the louver pitch have a very considerable effect on pressure drop as well as heat transfer rate. It is observed that increasing the fin pitch will relatively result in an increase in heat transfer rate but at the same time, the pressure drop will decrease. On the other hand, low pressure drop and low heat transfer rate will be obtained when the louver pitch is increased. Final result shows a good agreement between experimental and numerical results of the louvered fin which is about 12%. This indicates the capability of louvered fin in enhancing the performance of heat exchangers.

Heat Transfer Analysis of Shell-and-Helical-Coil Heat Exchangers

2016 ◽  
Author(s):  
Anthony Edward Morris ◽  
C. S. Wei ◽  
Runar Unnthorsson ◽  
Robert Dell
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Heat Exchangers ◽  
Transfer Rate ◽  
Green Roofs ◽  
Heat Transfer Analysis ◽  
Helical Coil ◽  
Straight Tube ◽  
Science And Art ◽  
Coil Heat

Since 2006, The Center for Innovation and Applied Technology (CIAT) at Cooper Union for the Advancement of Science and Art has been developing a system to use thermal pollution to heat the growth medium of green roofs. CIAT is researching various apparatus and techniques, including shell-and-tube and shell-and-coil heat exchangers, to improve its heated ground agricultural projects. There are limited recorded observations on shell-and-coil heat exchangers; therefore a laboratory work station was created of interchangeable components to test the efficiency of a variety of coil designs. This paper discusses the data collected on temperature, pressure, and flow rates for a straight tube and two different helical coils. The analysis of this data indicates the superiority of a helical coil design when compared to a straight tube design with respect to both rating and heat transfer rate. The same data analysis has lead to preliminary observations on how the contour properties of a helical coil influence the heat transfer rate through a coil. The authors intend to further this helical coil research to develop a useful mathematical model for determining efficient designs for shell-and-coil heat exchangers.

Heat Transfer in Film Boiling With Pulsating Pressures

1964 ◽  
Vol 86 (3) ◽  
pp. 457-460 ◽  
Author(s):  
D. A. Di Cicco ◽  
R. J. Schoenhals
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Heat Transfer Rate ◽  
High Purity ◽  
Atmospheric Pressure ◽  
Transfer Rate ◽  
Peak Pressure ◽  
Film Boiling ◽  
Periodic Pressure ◽  
Initial Results

The purpose of this exploratory experimental investigation was to determine the effect on the heat-transfer rate when a pulsating pressure is applied to a stable film boiling system. The test section used consisted of a 0.030-in-dia horizontal platinum wire. The boiling medium was monofluorotrichloromethane, C Cl3F, commercially available in high purity as Refrigerant 11. A boiling curve was obtained at atmospheric pressure. In addition, pulsating tests were conducted for various pulsing rates and for three different test wire temperatures. Periodic pressure pulses of approximately 100 psi were applied to the system. The initial results thus far obtained in this investigation show a substantial increase in the heat-transfer rate for pulsing frequencies ranging from 11.3 cps to 25.8 cps. The improvement is noted to be from 59.5 percent to 103 percent above the heat-transfer rate for film boiling at atmospheric pressure at the same temperature difference between the test wire and the fluid. It was also found that the heat-transfer rate achieved was higher than the average of the heat-transfer rate for atmospheric pressure film boiling and that for subcooled film boiling at the peak pressure achieved in pulsing. For the higher pulsing frequencies, the heat-transfer rate was found to be even greater than that for subcooled film boiling at the peak pressure.

A generalized moving-boundary algorithm to predict the heat transfer rate of counterflow heat exchangers for any phase configuration

2015 ◽  
Vol 79 ◽  
pp. 192-201 ◽  
Author(s):  
Ian H. Bell ◽  
Sylvain Quoilin ◽  
Emeline Georges ◽  
James E. Braun ◽  
Eckhard A. Groll ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Heat Exchangers ◽  
Transfer Rate ◽  
Moving Boundary

Thermal Assessment of Forced Convection Through Metal Foam Heat Exchangers

2011 ◽  
Vol 133 (11) ◽  
Author(s):  
A. Tamayol ◽  
K. Hooman
Keyword(s):  
Heat Transfer ◽  
Thermal Resistance ◽  
Forced Convection ◽  
Heat Transfer Rate ◽  
Heat Exchangers ◽  
Transfer Rate ◽  
Metal Foam ◽  
Convection Heat Transfer ◽  
Geometrical Parameters ◽  
Convection Heat

Using a thermal resistance approach, forced convection heat transfer through metal foam heat exchangers is studied theoretically. The complex microstructure of metal foams is modeled as a matrix of interconnected solid ligaments forming simple cubic arrays of cylinders. The geometrical parameters are evaluated from existing correlations in the literature with the exception of ligament diameter which is calculated from a compact relationship offered in the present study. The proposed, simple but accurate, thermal resistance model considers: the conduction inside the solid ligaments, the interfacial convection heat transfer, and convection heat transfer to (or from) the solid bounding walls. The present model makes it possible to conduct a parametric study. Based on the generated results, it is observed that the heat transfer rate from the heated plate has a direct relationship with the foam pore per inch (PPI) and solidity. Furthermore, it is noted that increasing the height of the metal foam layer augments the overall heat transfer rate; however, the increment is not linear. Results obtained from the proposed model were successfully compared with experimental data found in the literature for rectangular and tubular metal foam heat exchangers.

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