Validity of Performance Factors Used in Recent Studies On Heat Transfer Enhancement of Nanofluids

Abstract Many previous studies used the performance factors for the evaluation of heat transfer enhancement of nanofluids under the identical pumping power. The validity of the performance factors was not examined yet. The validity of the performance factors used in previous studies examined considered only flows in a circular tube based on the empirical correlations and experimental data. It was found that the performance factors used in the previous studies are not valid for the evaluation of heat transfer enhancement of nanofluids. Furthermore, this paper shows that the direct comparison of heat transfer rates without the assumptions of equal surface area and the equal temperature difference is suitable for the evaluation of heat transfer enhancement of single-phase fluids.

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Model-Based Shape Optimization of Three-Dimensional Complex Structure for Heat Transfer Enhancement in Single-Phase Flows

Proceedings of the 15th International Heat Transfer Conference ◽

10.1615/ihtc15.hte.008867 ◽

2014 ◽

Author(s):

Yosuke Hasegawa ◽

Naoki Shikazono

Keyword(s):

Heat Transfer ◽

Shape Optimization ◽

Heat Transfer Enhancement ◽

Single Phase ◽

Complex Structure ◽

Three Dimensional ◽

Transfer Enhancement ◽

Model Based

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Numerical study of heat transfer enhancement through a circular tube fitted with and without rectangular cut twisted tape insert

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/1017/1/012019 ◽

2021 ◽

Vol 1017 (1) ◽

pp. 012019

Author(s):

M U Hakim ◽

M W Hridoy ◽

M I Islam ◽

M S Rayhan

Keyword(s):

Heat Transfer ◽

Heat Transfer Enhancement ◽

Circular Tube ◽

Numerical Study ◽

Twisted Tape ◽

Transfer Enhancement

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Heat Transfer Enhancement of Single-Phase Internal Flows using Shape Optimization and Additively Manufactured Flow Structures

International Journal of Heat and Mass Transfer ◽

10.1016/j.ijheatmasstransfer.2021.121510 ◽

2021 ◽

Vol 177 ◽

pp. 121510

Author(s):

Hyunkyu Moon ◽

Kalyan Boyina ◽

Nenad Miljkovic ◽

William P. King

Keyword(s):

Heat Transfer ◽

Shape Optimization ◽

Heat Transfer Enhancement ◽

Single Phase ◽

Flow Structures ◽

Transfer Enhancement ◽

Internal Flows

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Design and testing of energy-efficient heat exchangers for Newtonian and non-Newtonian fluids – A review

Proceedings of the Institution of Mechanical Engineers Part A Journal of Power and Energy ◽

10.1177/09576509211047000 ◽

2021 ◽

pp. 095765092110470

Author(s):

Jayesh P ◽

Mukkamala Y ◽

Bibin John

Keyword(s):

Heat Transfer ◽

Heat Transfer Enhancement ◽

Heat Exchangers ◽

Internal Surface ◽

Surface Modifications ◽

Newtonian Fluids ◽

Tube Surface ◽

Pumping Power ◽

Transfer Enhancement ◽

The Impact

Heat transfer enhancement, pumping power and weight minimization in enhanced heat exchangers has long been achieved by deploying tubes with internal surface modifications like microgrooves, ribs, fins, knurls, and dimples with and without tube inserts. This article presents a very extensive review of experimental and computational studies on heat transfer enhancement, which covers convectional and unconventional working fluids under different fluid flow conditions. Compound augmentation with tube surface modifications and inserts has yielded enhancements in the overall heat transfer coefficient of over 116% in the fully developed turbulent flow regime. Exotic fluids like nano-coolants deployed in spiral grooved mircofin tubes yielded 196% enhancement in tube side heat transfer rate for concentrations as low as 0.5% by volume, while the thermal efficiency index measuring the overall enhancement in relation to the pumping power was 75%. However, reviews that address the combined effect of unconventional fluids, surface modifications and tube inserts on the overall thermo-hydraulic performance of annular heat exchangers seem to be limited. Further, nano-coolants aren’t frequently used in the process industry. The goal of this study is to document and evaluate the impact of cost-effective and energy-saving passive enhancement techniques such as tube surface modifications, tube inserts, and annular enhancement techniques on annular heat exchangers used in the process industries with Newtonian and non-Newtonian fluids. This review should be useful to engineers, academics and medical professionals working with non-Newtonian fluids and enhanced heat exchangers.

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Heat transfer enhancement of car radiator using aqua based magnesium oxide nanofluids

Thermal Science ◽

10.2298/tsci150526130a ◽

2015 ◽

Vol 19 (6) ◽

pp. 2039-2048 ◽

Cited By ~ 38

Author(s):

Hafiz Ali ◽

Muhammad Azhar ◽

Musab Saleem ◽

Qazi Saeed ◽

Ahmed Saieed

Keyword(s):

Heat Transfer ◽

Heat Transfer Enhancement ◽

Thermal Management ◽

Heat Transfer Performance ◽

Inlet Temperature ◽

Fluid Temperature ◽

Transfer Enhancement ◽

Volumetric Concentration ◽

Flow Rates ◽

Transfer Rates

The focus of this research paper is on the application of water based MgO nanofluids for thermal management of a car radiator. Nanofluids of different volumetric concentrations (i.e. 0.06%, 0.09% and 0.12%) were prepared and then experimentally tested for their heat transfer performance in a car radiator. All concentrations showed enhancement in heat transfer compared to the pure base fluid. A peak heat transfer enhancement of 31% was obtained at 0.12 % volumetric concentration of MgO in basefluid. The fluid flow rate was kept in a range of 8-16 liter per minute. Lower flow rates resulted in greater heat transfer rates as compared to heat transfer rates at higher flow rates for the same volumetric concentration. Heat transfer rates were found weakly dependent on the inlet fluid temperature. An increase of 8?C in inlet temperature showed only a 6% increase in heat transfer rate.

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