scholarly journals Numerical Investigation of the Effect of Inserted Twisted Tape inside Submerged Bundle Tubes on its Thermal Performance

2018 ◽  
Vol 24 (3) ◽  
pp. 42
Author(s):  
Kamal Mohammed Ali ◽  
Abdalrazzaq K. Abbas
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Reynolds Numbers ◽  
Twisted Tape ◽  
Ansys Fluent ◽  
Twist Ratio ◽  
Plain Tube ◽  
Exit Temperature ◽  
Inner Diameter ◽  
Film Heat Transfer

Twisted tape insertion in smooth plain tube is one of types of passive methods that is used to enhance heat transfer. Swirl fluid flow inside tube and related heat transfer characteristics are very complex. ANSYS FLUENT (V 16.1) and ASPEN industrial program are used in analyzing this technique for enhancement heat transfer. A circular plain tube has length L=8534mm and 17 mm inner diameter with twisted tape has twist ratio of y = (H/D) = (150/17) =8.8 along with a plain tube were considered for this study. Eight Reynolds numbers (Re) of 784, 1000, 2000, 3000, 4000, 5000, 6000 and 7000 are used to analyze the response of thermal performance. Crude oil API 28 exit temperature, film heat transfer coefficient, Nusselt number and overall enhancement ratio results are presented for both empty and inserted plain tube with comparison between the two cases. An increase of 0.76 to 2.36 overall enhancement is predicted with twist ratio 8.8 for Reynolds number 784 to 7000 respectively.  

scholarly journals Numerical Investigation of the Effect of Inserted Twisted Tape inside Submerged Bundle Tubes on its Thermal Performance

2018 ◽  
Vol 24 (7) ◽  
pp. 1
Author(s):  
Kamal Mohammed Ali ◽  
Abdalrazzaq K. Abbas
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Reynolds Numbers ◽  
Twisted Tape ◽  
Ansys Fluent ◽  
Twist Ratio ◽  
Plain Tube ◽  
Exit Temperature ◽  
Inner Diameter ◽  
Film Heat Transfer

Twisted tape insertion in the smooth plain tube is one of the types of passive methods that are used to enhance heat transfer. Swirl fluid flow inside the tube and related heat transfer characteristics are very complex. ANSYS FLUENT (V 16.1) and ASPEN industrial program are used in analyzing this technique for enhancement heat transfer. A circular plain tube has length L=8534mm and 17 mm inner diameter with a twisted tape of twist ratio of y = (H/D) = (150/17) =8.8 along the plain tube were considered for this study. Eight Reynolds numbers (Re) of 784, 1000, 2000, 3000, 4000, 5000, 6000 and 7000 are used to analyze the response of thermal performance. Crude oil API 28 exit temperature, film heat transfer coefficient, Nusselt number and overall enhancement ratio results are presented for both empty and inserted plain tube with a comparison between the two cases. An increase of 0.76 to 2.36 overall enhancement is predicted with twist ratio 8.8 for Reynolds number 784 to 7000 respectively.  

Numerical and experimental thermal performance with entropy generation analysis on tube with helical screw tape inserts at number of strips in turbulent flow

2020 ◽  
pp. 095440622093773
Author(s):  
Shashank Ranjan Chaurasia ◽  
RM Sarviya
Keyword(s):  
Reynolds Number ◽  
Nusselt Number ◽  
Entropy Generation ◽  
Thermal Performance ◽  
Twisted Tape ◽  
Maximum Enhancement ◽  
Twist Ratio ◽  
Plain Tube ◽  
Volume Method ◽  
Single Strip

In the heat exchangers, twisted tape insert is a technique to enhance heat transfer. In this paper, the experimental and numerical investigations are arranged to analyze thermal performance with entropy generation analysis on single and double strip helical screw tape inserts. The finite volume method is used with shear stress transport K-ω model to analyze fluid flow in tube with inserts. The Nusselt number attained enhancement with double strip as compared to single strip helical screw inserts at decreased values of twist ratio and increased values of Reynolds number. However, the Nusselt number attained maximum enhancement of 112% with double strip helical screw insert than plain tube at 4000 of Reynolds number (Re). The common correlations for Nusselt number and friction factor are generated with respect to Reynolds number, number of the strips and twist ratio. Entropy generation analysis is also performed. The thermal performance factor attained its enhancement with double strip than single strip helical screw inserts at twist ratio of 2.5 and 3; whereas, double strip helical screw insert attained maximum value of 1.5 at twist ratio of 2.5 and Reynolds number of 16000. The double strip helical screw inserts are suitable for miniaturization of heat exchanger.

Heat Transfer Enhancement in a Tube Fitted With Twisted Tape Swirl Generator

2010 ◽  
Author(s):  
Smith Eiamsa-ard ◽  
Panida Seemawute ◽  
Khwanchit Wongcharee
Keyword(s):  
Heat Transfer ◽  
Transfer Rate ◽  
Working Fluid ◽  
Twisted Tape ◽  
Transfer Enhancement ◽  
Flow Friction ◽  
Friction Heat ◽  
Swirl Generator ◽  
Twist Ratio ◽  
Plain Tube

Flow friction, heat transfer and thermal performance characteristics in a tube fitted with peripherally-cut twisted tape (PT) have been experimentally investigated. The twist ratio (y/W) of twisted tape was varied from 3 to 5 while the depth of peripheral cut ratio (d/W) and the width of peripheral cut ratio (w/W) were both kept constant at 0.22. The experiments were conducted for the Reynolds number ranging from 5100 to 19,700, using water as a working fluid. The plain tube and the tube equipped with the typical twisted tape (TT) with three different twist ratios (y/W = 3, 4 and 5) were also tested for comparison. The obtained results reveal that the use of PT enhances Nusselt number up to 211% and 138% compared to those of the plain tube and the tube with TT, respectively. It is also found that heat transfer rate increases with decreasing twist ratio. Additionally, the performance evaluation to assess the real benefits in using the PT as heat transfer enhancer has also been determined.

Tapered Twisted Tape Inserts for Enhanced Heat Transfer

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
B. V. N. Ramakumar ◽  
J. D. Arsha ◽  
Praveen Tayal
Keyword(s):  
Heat Transfer ◽  
Numerical Study ◽  
Flow Direction ◽  
Twisted Tape ◽  
Complex Flow ◽  
Ansys Fluent ◽  
Taper Angle ◽  
Twisted Tapes ◽  
Plain Tube ◽  
Enhancing Heat Transfer

Insertion of twisted tapes in smooth channels is one of the passive methods used for enhancing heat transfer. Flow and associated heat transfer characteristics of these channels are very complex. Understanding this complex flow is helpful while designing new passive methods. Numerical methods like computational fluid dynamics (CFD) are gaining much popularity for analyzing and designing these heat transfer enhancement techniques. This paper focuses on such a numerical study. The preliminary study is focused on development of numerical methodology through validation. Successive studies are aimed at development of an innovative design for twisted tape. Twisted tapes with taper angle (tapered twisted tapes, i.e., tape width decreases along the flow direction) are developed and evaluated on the basis of the performance of these tapes with those of conventional tapes. A circular tube with tapered twisted tape with a twist ratio of 3 and taper angles of 0.3, 0.4, 0.5, 0.6, and 0.7 is considered for this study along with a plain tube. Three Reynolds numbers (Re) of 8545, 11393, and 13333 are considered to examine the sensitivity of the performance. Simulations are performed with a commercially available CFD tool, ansys fluent (v14.0). Heat transfer and pressure drop results are presented in the form of Nusselt number (Nu), friction factor (f), and overall enhancement ratio (η). An increase of 17% in overall enhancement is predicted with taper angle of 0.5.

scholarly journals Numerical study on the influencing mechanism of twisted ratio in outward convex corrugated tubes with a twisted tape insert

2018 ◽  
Vol 22 (Suppl. 2) ◽  
pp. 577-584
Author(s):  
Huaizhi Han ◽  
Longbin Yang ◽  
Yiran Hu ◽  
Ruitian Yu ◽  
Qun Zhang
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Numerical Study ◽  
Twisted Tape ◽  
High Twist ◽  
Numerical Investigations ◽  
Corrugated Tube ◽  
Influencing Mechanism ◽  
Flow And Heat Transfer ◽  
Twist Ratio

Numerical investigations were conducted on flow and heat transfer in an outward convex corrugated tube with various structural twisted tape inserts. The study investigated the influence of twisted ratio on thermodynamic regulation and mechanism in the corrugated tube. The results indicate that Nusselt number in the corrugated tube (Nuc) exceeds those in the corrugated tube and smooth tube by 120-136% and 171-317%, respectively. Meanwhile, the friction factor increases by 148-153% and 476-514%, respectively. The best overall thermal performance (h = 1.97) is obtained with a high twist ratio (y/w = 5). However, the highest thermal performance (Nuc/Nus = 4.78) is obtained with the lowest twist ratio (y/w = 1.25).

Characterization of Heat Transfer by Overlapped-Quadruple Counter Tapes

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
S. Eiamsa-Ard ◽  
P. Samravysin
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Twisted Tape ◽  
Flux Boundary Condition ◽  
Turbulent Flow Regime ◽  
Thermal Enhancement ◽  
Twist Ratio ◽  
Enhancing Heat Transfer ◽  
Uniform Wall

This paper deals with the influence of overlapped-quadruple twisted tape (OQT) and typical quadruple twisted tape (QT) on the enhancing heat transfer rate in a heat exchanger tube. The effects of tube orientation (co-tapes and counter tapes), tape arrangement (cross and parallel arrangements), and overlapped twist ratio (yo/y = 0.625, 0.75, and 0.875) were investigated. The experiments were performed in the turbulent flow regime (5000 ≤ Re ≤ 20,000) under uniform wall heat flux boundary condition, using air as the testing fluid. The experimental results indicates that all OQTs consistently yield higher Nusselt number and thermal performance than QTs. The tapes in cross arrangement show better heat transfer enhancement and thermal performance than the ones in parallel arrangement. Heat transfer, friction loss, and thermal performance increase with decreasing overlapped twist ratio. The maximum thermal enhancement factor (TEF) of 1.58 is achieved by the use of overlapped-quadruple counter tapes in cross arrangement (CC-OQTs) with yo/y = 0.625 at the lowest Reynolds number of 5000.

scholarly journals Comparative Studies on Thermal Performance of Conic Cut Twist Tape Inserts with SiO2and TiO2Nanofluids

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Sami D. Salman ◽  
Abdul Amir H. Kadhum ◽  
Mohd S. Takriff ◽  
Abu Bakar Mohamad
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Thermal Performance ◽  
Volume Concentration ◽  
Twisted Tape ◽  
Maximum Heat ◽  
Performance Factor ◽  
Thermal Performance Factor ◽  
Maximum Heat Transfer ◽  
Twist Ratio

This paper presents a comparison study on thermal performance conic cut twist tape inserts in laminar flow of nanofluids through a constant heat fluxed tube. Three tape configurations, namely, quadrant cut twisted tape (QCT), parabolic half cut twisted tape (PCT), and triangular cut twisted (VCT) of twist ratioy= 2.93 and cut depthde= 0.5 cm were used with 1% and 2% volume concentration of SiO2/water and TiO2/water nanofluids. Typical twist tape with twist ratio ofy= 2.93 was used for comparison. The results show that the heat transfer was enhanced by increasing of Reynolds number and nanoparticles concentration of nanofluid. The results have also revealed that the use of twist tape enhanced the heat transfer coefficient significantly and maximum heat transfer enhancement was achieved by the presence of triangular cut twist tape insert with 2% volume concentration of SiO2nanofluid. Over the range investigated, the maximum thermal performance factor of 5.13 is found with the simultaneous use of the SiO2nanofluid at 2% volume concentration VCT at Reynolds number of 220. Furthermore, new empirical correlations for Nusselt number, friction factor, and thermal performance factor are developed and reported.

Heat Transfer of rGO/CO3O4 Hybrid Nanomaterial-Based Nanofluids and Twisted Tape Configurations in a Tube

2020 ◽  
Vol 13 (3) ◽  
Author(s):  
L. Syam Sundar ◽  
E. Venkata Ramana ◽  
Zafar Said ◽  
António M.B. Pereira ◽  
Antonio C.M. Sousa
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Graphene Oxide ◽  
Friction Factor ◽  
Thermal Performance ◽  
Twisted Tape ◽  
Particle Loading ◽  
Hybrid Nanomaterial ◽  
Reduced Graphene ◽  
Plain Tube

Abstract The friction factor, thermal performance, and heat transfer are experimentally analyzed for reduced-graphene oxide/cobalt oxide (rGO/CO3O4) hybrid nanomaterial-based nanofluid circulating in a plain tube with and without twisted tape inserts having different pitches. The reduced-graphene oxide/cobalt oxide (rGO/CO3O4) hybrid nanomaterial is prepared using in situ/chemical reduction technique and then characterized with transmission electron microscope, X-ray diffraction, and magnetometry. The experiments were conducted with different values of particle loading (0.05%, 0.1%, and 0.2%) and Reynolds number (2000–2,020,000). Three twisted tape inserts of helixes 285 mm, 190 mm, and 95 mm were used. The nanofluids was produced from the addition of the hybrid nanomaterial to water yield an increase, as compared to the basefluid (water), of the Nusselt number, which is further enhanced by increasing the nanoparticle loading. Therefore, when compared to water, the Nusselt number is enhanced by 25.65%, with no twisted tape and by 79.16% with twisted tape with helix of 95 mm for the nanofluid of 0.2% volume concentration. However, when compared to water, there is a slight friction factor penalty with the 0.2% particle loading of 1.11-times and 1.49-times for the plain tube and for the 95-mm twisted tape helix, respectively. The thermal performance factor gets enhanced by increasing the nanoparticles concentration of the hybrid nanofluids with or without twisted tape inserts, and it is always higher than one. Based on the experimental data, regression equations were developed for the Nusselt number and friction factor.

scholarly journals Numerical Analysis of Flow and Heat Transfer Enhancement in A Horizontal Pipe with Plain and Dimple Twisted Tape

2021 ◽  
Vol 82 (2) ◽  
pp. 106-119
Author(s):  
Harish H. V. ◽  
Manjunath K. ◽  
Rangaswamy T.
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Constant Heat Flux ◽  
Hydraulic Performance ◽  
Twisted Tape ◽  
Horizontal Pipe ◽  
Circular Duct ◽  
Performance Factor ◽  
Thermal Performance Factor ◽  
Plain Tube

In order to improve thermo-hydraulic performance of laminar flow various techniques has been used among which a plain tube with twisted tape insert is widely used. The main objective is to numerically study flow field in order to enhance heat transfer, through a circular pipe built in with/without Dimples on twisted strip. Effect of plain and dimple strip on thermo hydraulic performance discussed. The analysis results for laminar range of 800<Re<2000 is obtained with twist ratio of the strip is 3.0. Analysis is carried for full length tape with constant heat flux. The simulation results of Nusselt number versus Reynolds number of the plain, plain twisted tape and Dimple twisted tape with the experimental data give variation of 2.5, 5.75 and 9.5%. The friction factor of Dimple twisted tape tube is 6 to 13 times that of the plain tube. The thermal performance factor of the Dimple twisted tape and plain twisted tape tube is 4 to 15% and 3 to 12 % respectively higher than that of plain tube. Due to increase in thermal performance factor of induced strip with dimples there is an intensification of heat transfer obtained through circular duct with dimple twisted tape insert than that of plain twisted tape and plain pipe. The use of a twisted tube compounded with dimples is feasible in terms of energy saving at lower Reynolds numbers. Present study is applicable for design of compact heat exchanger in order to optimize energy consumption.

scholarly journals CFD Analysis of Heat Transfer and Friction Factor Characteristics in a Circular Tube Fitted with Quadrant-Cut Twisted Tape Inserts

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Sami D. Salman ◽  
Abdul Amir H. Kadhum ◽  
Mohd S. Takriff ◽  
Abu Bakar Mohamad
Keyword(s):  
Heat Transfer ◽  
Friction Factor ◽  
Cfd Simulation ◽  
Swirling Flow ◽  
Circular Tube ◽  
3D Models ◽  
Twisted Tape ◽  
Twist Ratio ◽  
Plain Tube ◽  
Cut Depth

This paper reports numerical investigations of heat transfer and friction factor characteristics in swirling flow conditions using CFD simulation. A commercial CFD package, FLUENT 6.3.26, was used in this study. 3D models for circular tube fitted with classical and quadrant-cut twisted tape (QCT) inserts with three twist ratios (y= 2.93, 3.91, and 4.89) and different cut depths (w= 0.5, 1.0, and 1.5 cm) were generated for the simulation. The data obtained from the CFD simulation were verified with the literature correlations of plain tube with the discrepancy of less than ±8% for Nusselt number and ±10% for friction factor. The results show that there was a significant increase in heat transfer coefficient and friction factor in the tube fitted with quadrant-cut twisted tape (QCT) with decreasing of twist ratio (y) and cut depth (w). Furthermore, the configuration of QCT insert with a twist ratio ofy= 2.93 and a cut depth ofw= 0.5 cm offered higher heat transfer rate and friction factor than other twist ratios.

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