A Review on Enhancement of Heat Transfer Techniques

Gugulothu, Ravi; Reddy, K. Vijaya Kumar; Somanchi, Naga Sarada; Adithya, Etukuri Lalith

doi:10.1016/j.matpr.2017.01.119

Cited by 31 publications

(23 citation statements)

References 7 publications

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“…Heat transfer improvement, in all forms of thermo-mechanical apparatus, is critical for the industry as it results in a decrease in size and weight, in addition to saving primary resources. Heat transfer augmentation techniques can be classified into two groups: (i) active methods, (ii) passive methods [1][2][3]. In the literature, there have been many laboratory experiments on heat augmentation techniques that utilize twisted tape as a passive technique [4][5][6][7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Parametric CFD Thermal Performance Analysis of Full, Medium, Half and Short Length Dimple Solar Air Tube

Alam

Souayeh

2021

Sustainability

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In the present decade, research regarding solar thermal air heaters (SAHs) has noticed a continuous progression in thermo-hydraulic performance augmentation approaches. There now exists a wide variety of thermo-hydraulic performance augmentation approaches and researchers have designated various structures. Nevertheless, there seems to be no generalization to any of the approaches employed. The present numerical investigation reports on the thermo-hydraulic characteristics and thermal performance for flow through a varied length (full, medium, half, and short length) dimple solar air heater (SAH) tube. The study highlights recent developments on enhanced tubes to augment heat transfer in SAH. The influence of different length ratio, dimple height ratio (H), and pitch ratio (s) on thermo-hydraulic characteristics have been investigated in the Reynolds number (Re) range from 5000 to 25,000. Air is used as the working fluid. The commercial software ANSYS Fluent is used for simulation. The shear stress transport (SST) model is used as the turbulence model. Thermal energy transport coefficient is increased in the full-length dimple tube (FLDT), compared to the medium-length dimple tube (MLDT), half-length dimple tube (HLDT) and short-length dimple tube (SLDT). Similarly, the pitch ratio (s) has more influence on Nusselt number (Nu) compared to the dimple height ratio (H). The friction factor decreases with an increase in pitch ratio. Nu increases and f decreases with increasing Re for all combinations of H and s. Low s and higher H yields high enhancement of HT and PD. Integration of artificial roughness on the tube increases the values of Nu and f by 5.12 times and 77.23 times for H = 0.07, s = 1.0 at Re value of 5000 and 25,000, respectively, in regard to the plain tube. For all the tested cases, the thermo-hydraulic performances (η) are greater than unity.

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Section: Introductionmentioning

confidence: 99%

Parametric CFD Thermal Performance Analysis of Full, Medium, Half and Short Length Dimple Solar Air Tube

Alam

Souayeh

2021

Sustainability

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“…Heat transfer enhancement techniques are very important to save energy. In the past decades, heat transfer enhancement technology has been developed and widely applied [2]. As cooling is one of the essential technical challenges that faces many diverse industries, including transportation, microelectronics and manufacturing [3], this raises the need for new and advanced coolants with improved performance.…”

Section: Introductionmentioning

confidence: 99%

Effect of Nano-Fluid Jet Impingement on Heat Transfer of Surfaces With Different Shapes

Ewis¹,

Mageed²,

El-Morsi³

et al. 2019

IJASTR

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This study experimentally investigates heat transfer enhancement of an impinging free liquid jet on a hot surface of copper plate with different shapes, by replacing the base fluid, distilled water with Al 2 O 3 nanofluid (10 nm), different shapes of heated surface of copper plate (Flat, Concave, Convex Wavedand Corrugated), different impingement Reynolds numbers ranging from (7,565 to nearly 18,460), five nanoparticles mass concentrations (0%, 0.2%, 0.5%, 1% and 2%) were studied using distilled water and AL 2 O 3 nanofluid jet impingement.The results of the current experiments show that increasing the volume flow rate of the cooling fluid improves the heat transfer between the free liquid jet and the hot copper plate.Moreover, using nanofluid jet enhances the heat transfer.Additionally, increasing the surface area enhances the heat transfer between the cooling fluid and the hot plate and decreases the cooling time.Finally, it was noted that surface shape, impingement Reynolds number and nanofluid concentration affect the heat transfer enhancement processsignificantly.The accumulative effect of using nanafluid jet 2% with corrugated surface with higher flow rate on Nusselt number can reach 185%. On the other hand, using a dispersant for the nanofluid as polyethylene glycol keeps the nanofluid suspension and prevents agglomeration, but reduces its heat transfer enhancement effect.

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“…These systems are widely used in many industries such as transportations, airconditioning systems, cooling systems, nuclear reactors, cooling of electronic parts, space and defense, optical and biomedical applications. [1]. In general, the enhancement techniques classified into two categories.…”

Section: Introductionmentioning

confidence: 99%

Effects of Coil Pitch Spacing on Heat Transfer Performance of Nanofluid Turbulent Flow through Helical Microtube Heat Exchanger

Rasheed¹,

Alias²,

Salman³

2019

IJET

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This article provides Numerical simulation on forced convective heat transfer performance of Nanofluid flowing through copper helical microtube of inner diameter of 1.5 mm with different pitch using ANSYS-FLUENT 18.0. The simulation was performed for water, CuO/water, Al2O3/water Nanofluid with 1-2% volume concentration and different pitch of microtube (10, 14 and 18 mm) for turbulent flow regime of Reynolds number varied 5000 to 20000 and governing equations of mass, momentum and heat transfer were solved simultaneously, using the k-e two equations turbulence model. Based on the obtained results, regardless of the concentrations used, the nanofluids exhibited a higher transfer rate than water. This is mainly attributed to the nanoparticles that are in the used nanofluids. The friction factor and the heat transfer rate were enhanced considerably due to the shape and size of the tube, which in this case is a helical microtube. Moreover, the maximum heat transfer performance has been conducted by Al2O3/water Nanofluid with 2% volume concentration and microtube pitch of 18 mm.

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A Review on Enhancement of Heat Transfer Techniques

Cited by 31 publications

References 7 publications

Parametric CFD Thermal Performance Analysis of Full, Medium, Half and Short Length Dimple Solar Air Tube

Parametric CFD Thermal Performance Analysis of Full, Medium, Half and Short Length Dimple Solar Air Tube

Effect of Nano-Fluid Jet Impingement on Heat Transfer of Surfaces With Different Shapes

Effects of Coil Pitch Spacing on Heat Transfer Performance of Nanofluid Turbulent Flow through Helical Microtube Heat Exchanger

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