Sensitivity Analysis of a Heat Exchanger Tube Fitted With Cross-Cut Twisted Tape With Alternate Axis

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
M. E. Nakhchi ◽  
J. A. Esfahani
Keyword(s):  
Heat Transfer ◽  
Sensitivity Analysis ◽  
Reynolds Number ◽  
Heat Exchanger ◽  
Thermal Performance ◽  
Diameter Ratio ◽  
Design Parameters ◽  
Twisted Tape ◽  
Heat Exchanger Tube ◽  
Exchanger Tube

Numerical simulations are used to analyze the thermal performance of turbulent flow inside heat exchanger tube fitted with cross-cut twisted tape with alternate axis (CCTA). The design parameters include the Reynolds number (5000<Re<15,000), cross-cut width ratio (0.7<b/D<0.9), cross-cut length ratio (2<s/D<2.5), and twist ratio (2<y/D<4). The objective functions are the Nusselt number ratio (Nu/Nus), the friction factor ratio (f/fs), and the thermal performance (η). Response surface method (RSM) is used to construct second-order polynomial correlations as functions of design parameters. The regression analysis shows that heat transfer ratio decreased with increasing both the Reynolds number and the width to diameter ratio of the twisted tape. This means that the twisted tape has more influence on heat transfer at smaller inlet fluid velocities. Sensitivity analysis reveals that among the effective input parameters, the sensitivity of Nu/Nus to the Reynolds number is the highest. The results reveal that thermal performance enhances with increasing the width to diameter ratio of the twisted tape (b/D). The maximum thermal performance factor of 1.531 is obtained for the case of Re=5000, b/D=0.9, s/D=2.5, and y/D=4.

Effect of Twin Delta-Winged Twisted-Tape on Thermal Performance of Heat Exchanger Tube

2013 ◽  
Vol 34 (15) ◽  
pp. 1278-1288 ◽  
Author(s):  
Smith Eiamsa-ard ◽  
Chayut Nuntadusit ◽  
Pongjet Promvonge
Keyword(s):  
Heat Exchanger ◽  
Thermal Performance ◽  
Twisted Tape ◽  
Heat Exchanger Tube ◽  
Exchanger Tube

scholarly journals Analysis and Implementation of Thermal Heat Exchanger Tube Performance with Helically Pierced Twisted Tape Inserts Using ANFIS Model

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Faisal Altarazi ◽  
Sunil Kumar ◽  
Gaurav Gupta ◽  
Muhammad Gulzar ◽  
Yaé Ulrich Gaba ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
System Modeling ◽  
Diameter Ratio ◽  
Twisted Tape ◽  
Heat Exchanger Tube ◽  
Anfis Model ◽  
Inference System ◽  
Relative Pitch ◽  
Pitch Ratio ◽  
Exchanger Tube

The present work used ANFIS, an adaptive neuro-fuzzy inference system modeling to analyze the effect of the variable parameters of helically pierced twisted tape inserts on the Nusselt number, friction factor, and thermo-hydraulic heat exchanger tube performance. The experimental data utilized for ANFIS modeling considered a diameter ratio ranging from 0.57 to 0.80, a relative pitch ratio ranging from 0.046 to 0.107, a perforation index ranging from 5% to 20% as variable twisted tape parameters and flow parameters. The Reynolds number varies from 4000 to 30000. The analysis showed that the maximum thermo-hydraulic performance was obtained at a diameter ratio of 0.65, a relative pitch ratio of 0.085, and a perforation index equal to 10%. The result predicts that the ANFIS model and experimental results are in good agreement as they have only ±0.53% deviations.

scholarly journals Fluid flow and heat transfer enhancement in wings with combined solid ring twisted tape inserts circular heat exchanger tube

2019 ◽  
Vol 23 (6 Part B) ◽  
pp. 3893-3903
Author(s):  
Ravi Datt ◽  
Mangal Bhist ◽  
Alok Kothiyal ◽  
Rajesh Maithani ◽  
Anil Kumar
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Heat Exchanger ◽  
Hydrodynamic Performance ◽  
Turbulent Heat Transfer ◽  
Twisted Tape ◽  
Turbulent Heat ◽  
Heat Exchanger Tube ◽  
Circular Heat ◽  
Exchanger Tube

Experimental examination is carried out to study the turbulent heat transfer and fluid-flow characteristics in circular heat exchanger tube using combined wing with solid ring twisted tape inserts. A series of experiments has been performed with the range of Reynolds number varied from 3000 to 21000, number of twisted taped inserts, NTT, varied from 1.0 to 4.0 with constant value of other twisted tape parameters such as rings pitch ratio, dR /DT = 1.0, wing pitch ratio, PW /WT = = 3.0, and wing depth ratio, Wd /WT = 1.67. Based on the examined, turbulent heat transfer and fluid-flow in wing with combined solid ring twisted tape inserts results are compared with plain circular tube under same operating conditions. The experimental results show that the heat transfer is increased around 5.66 times than plane circular heat exchanger tube. The thermal and hydrodynamic performance parameter based on equal pumping power, ?p, was found to be highest for NTT = 3.0. The optimum value of thermal and hydrodynamic performance has been found to be 2.74 for Reynolds mumber of 3000 within the range of the parameters investigated. Multiple wings with solid rings twisted tape inserts have been also shown to be thermally as well as hydraulically better in comparison to other similar twisted tape insert geometries.

Development of new correlations for heat transfer and friction loss of solid ring with combined square wing twisted tape inserts heat exchanger tube

2018 ◽  
Vol 32 (2) ◽  
pp. 179-200 ◽  
Author(s):  
Ravi Datt ◽  
Mangal Singh Bhist ◽  
Alok Darshan Kotiyal ◽  
Rajesh Maithani ◽  
Anil Kumar
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Friction Loss ◽  
Twisted Tape ◽  
Heat Exchanger Tube ◽  
Exchanger Tube

scholarly journals Influences of Flow Attack Angles and Flow Directions on Heat Transfer Rate, Pressure Loss, and Thermal Performance in Heat Exchanger Tube with V-Wavy Surface

2018 ◽  
Vol 2018 ◽  
pp. 1-22
Author(s):  
Amnart Boonloi ◽  
Withada Jedsadaratanachai
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Thermal Performance ◽  
Test Section ◽  
Vortex Flow ◽  
Wavy Surface ◽  
Heat Exchanger Tube ◽  
Flow And Heat Transfer ◽  
Flow Directions ◽  
Exchanger Tube

Numerical investigations on flow and heat transfer characteristics in the heat exchanger tube with the V-wavy surface are presented. The finite volume method with the SIMPLE algorithm is selected to solve the present problem. The effects of flow attack angles (α = 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, and 60°) and flow directions (V-tip pointing downstream known as “V-Downstream” and V-tip pointing upstream known as “V-Upstream”) for the V-wavy surface on flow and heat transfer patterns are considered for both laminar and turbulent regions. The laminar regime is studied in the range Re = 100–1200, while the turbulent region is investigated in the range Re = 3000–10,000. The mechanisms on flow and heat transfer in the test section are reported. The numerical results reveal that the V-wavy surface changes the flow structure in the test section. The vortex flow is produced by the V-wavy surface. The vortex flow disturbs the thermal boundary layer on the heat transfer surface that is the reason for heat transfer and thermal performance enhancements. The optimum flow attack angles of the V-wavy surface for laminar and turbulent regimes are concluded.

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