Effect of Helical Surface Disc Turbulators on Heat Transfer and Friction Factor Characteristics in the Annuli of a Double‐Pipe Heat Exchanger

Heat transfer and overall heat transfer in a double pipe heat exchanger fitted with twisted-tape elements and titanium dioxide nanofluid were studied experimentally. The inner and outer diameters of the inner tube were 8 and 16 mm, respectively, and cold and hot water were used as working fluids in shell side and tube side. The twisted tapes were made from aluminum sheet with tape thickness (d) of 1 mm, width (W) of 5 mm, and length of 120 cm. Titanium dioxide nanoparticles with a diameter of 30 nm and a volume concentration of 0.01% (v/v) were prepared. The effects of temperature, mass flow rate, and concentration of nanoparticles on the overall heat transfer coefficient, heat transfer changes in the turbulent flow regimeRe≥2300, and counter current flow were investigated. When using twisted tape and nanofluid, heat transfer coefficient was about 10 to 25 percent higher than when they were not used. It was also observed that the heat transfer coefficient increases with operating temperature and mass flow rate. The experimental results also showed that 0.01% TiO2/water nanofluid with twisted tape has slightly higher friction factor and pressure drop when compared to 0.01% TiO2/water nanofluid without twisted tape. The empirical correlations proposed for friction factor are in good agreement with the experimental data.

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Experimental Investigation of Heat Transfer and Friction Factor Characteristics Using Helical Surface Ring Turbulators in an Annulli of Double Pipe Heat Exchanger

Volume 2: Heat Exchanger Technologies; Plant Performance; Thermal Hydraulics and Computational Fluid Dynamics; Water Management for Power Systems; Student Competition ◽

10.1115/power2018-7231 ◽

2018 ◽

Cited By ~ 2

Author(s):

Saurabh Yadav ◽

Maheandera Prabu Paulraj ◽

Santosh K. Sahu

Keyword(s):

Heat Transfer ◽

Experimental Investigation ◽

Heat Exchanger ◽

Fluid Flows ◽

Diameter Ratio ◽

Helical Surface ◽

Pitch Ratio ◽

Plain Surface ◽

Double Pipe ◽

Pipe Heat

Augmentation in heat transfer is very useful for various engineering and scientific applications due to the call for energy and cost saving. The heat transfer and pressure drop characteristics in annuli of double pipe heat exchanger using helical and plain surface ring turbulators are studied through experimental investigation. The effect of helical surface ring turbulators and plain surface ring turbulators are studied for varied range of pitch ratio (4.0–6.4), Reynolds Number (3,000–10,500) and two different diameter ratios (0.475 and 0.54). Water (hot fluid) flows in the inner tube and air (cold fluid) flows through the annulus. The tests are conducted for air with uniform wall temperature condition. The heat exchanger with least pitch and least diameter ratio is found to exhibit the highest Nusselt number and pressure drop. Results indicate that maximum enhancement is obtained for smallest diameter ratio 0.475 and pitch ratio 4.0 at lowest Reynolds Number. Also, thermal performance factor is always greater than unity for the DPHE using helical surface turbulators. Correlations have been developed for enhancement in Nusselt number and friction factor; show the good agreement with experimental test data within test range.

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Study the Effect of SiO2 Nanofluids on Heat Transfer in Double Pipe Heat Exchanger

Revista de Chimie ◽

10.37358/rc.20.5.8119 ◽

2020 ◽

Vol 71 (5) ◽

pp. 117-124

Author(s):

Noor Sabeeh Majeed ◽

Shaymaa Mahdi Salih ◽

Hussam Nadum Abda Lraheemal Ani ◽

Basma Abbas Abdulmajeed ◽

Paul Constantin Albu ◽

...

Keyword(s):

Heat Transfer ◽

Heat Transfer Coefficient ◽

Heat Exchanger ◽

Transfer Coefficient ◽

Friction Factor ◽

Sio2 Nanoparticles ◽

Particle Sizes ◽

Nanoparticle Concentration ◽

Double Pipe ◽

Pipe Heat

In this paper the effect of nanofluid is studied in the double pipe heat exchanger counter current flow, the viscosity of nanofluids are measured at different temperatures and different particle sizes. SiO2 nanoparticles are dispersed at different concentrations (0.2-2) % with different particle sizes of (50-25) nm in base fluid of water. The friction factor and heat transfer coefficient are calculated at different nanoparticle sizes, the results showed that the viscosity was increased as nanoparticle concentration increased. The friction factor is increased as SiO2 nanoparticles concentration and increased as nanoparticles size decreased. The heat transfer coefficient increased as nanoparticle concentration increased and particles size decrease.

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3D Numerical Study of Conical and Fusiform Turbulators for Heat Transfer Improvement in a Double-Pipe Heat Exchanger

International Journal of Heat and Mass Transfer ◽

10.1016/j.ijheatmasstransfer.2021.120995 ◽

2021 ◽

Vol 170 ◽

pp. 120995

Author(s):

Qingang Xiong ◽

Mohsen Izadi ◽

Mozafar Shokri rad ◽

S.A. Shehzad ◽

Hussein A. Mohammed

Keyword(s):

Heat Transfer ◽

Heat Exchanger ◽

Numerical Study ◽

Double Pipe ◽

Heat Transfer Improvement ◽

Pipe Heat

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Investigation of Overlapped Twisted Tapes Inserted in a Double-Pipe Heat Exchanger Using Two-Phase Nanofluid

Nanomaterials ◽

10.3390/nano10091656 ◽

2020 ◽

Vol 10 (9) ◽

pp. 1656 ◽

Cited By ~ 1

Author(s):

Mehdi Ghalambaz ◽

Hossein Arasteh ◽

Ramin Mashayekhi ◽

Amir Keshmiri ◽

Pouyan Talebizadehsardari ◽

...

Keyword(s):

Heat Transfer ◽

Reynolds Number ◽

Performance Evaluation ◽

Heat Exchanger ◽

Evaluation Criterion ◽

Twisted Tape ◽

Performance Evaluation Criterion ◽

Twisted Tapes ◽

Double Pipe ◽

Pipe Heat

This study investigated the laminar convective heat transfer and fluid flow of Al2O3 nanofluid in a counter flow double-pipe heat exchanger equipped with overlapped twisted tape inserts in both inner and outer tubes. Two models of the same (co-swirling twisted tapes) and opposite (counter-swirling twisted tapes) angular directions for the stationary twisted tapes were considered. The computational fluid dynamic simulations were conducted through varying the design parameters, including the angular direction of twisted tape inserts, nanofluid volume concentration, and Reynolds number. It was found that inserting the overlapped twisted tapes in the heat exchanger significantly increases the thermal performance as well as the friction factor compared with the plain heat exchanger. The results indicate that models of co-swirling twisted tapes and counter-swirling twisted tapes increase the average Nusselt number by almost 35.2–66.2% and 42.1–68.7% over the Reynolds number ranging 250–1000, respectively. To assess the interplay between heat transfer enhancement and pressure loss penalty, the dimensionless number of performance evaluation criterion was calculated for all the captured configurations. Ultimately, the highest value of performance evaluation criterion is equal to 1.40 and 1.26 at inner and outer tubes at the Reynolds number of 1000 and the volume fraction of 3% in the case of counter-swirling twisted tapes model.

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A Conjugate Heat Transfer Analysis of a Triangular Finned Annulus Based on DG-FEM

Mathematical Problems in Engineering ◽

10.1155/2018/6947565 ◽

2018 ◽

Vol 2018 ◽

pp. 1-18

Author(s):

Muhammad Ishaq ◽

Khalid Saifullah Syed ◽

Zafar Iqbal ◽

Ahmad Hassan

Keyword(s):

Heat Transfer ◽

Heat Exchanger ◽

Conjugate Heat Transfer ◽

Strong Influence ◽

Heat Transfer Analysis ◽

Conductivity Ratio ◽

Geometric Configurations ◽

Specific Configuration ◽

Double Pipe ◽

Pipe Heat

A DG-FEM based numerical investigation has been performed to explore the influence of the various geometric configurations on the thermal performance of the conjugate heat transfer analysis in the triangular finned double pipe heat exchanger. The computed results dictate that Nusselt number in general rises with values of the conductivity ratio of solid and fluid, for the specific configuration parameters considered here. However, the performance of these parameters shows strong influence on the conductivity ratio. Consequently, these parameters must be selected in consideration of the thermal resistance, for better design of heat exchanger.

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