Experimental and numerical study on heat transfer enhancement using ultrasonic vibration in a double-pipe heat exchanger

Setareh, Milad; Saffar‐Avval, Majid; Abdullah, Amir

doi:10.1016/j.applthermaleng.2019.113867

Cited by 85 publications

(14 citation statements)

References 38 publications

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“…Vibrations characterized by low acoustic frequencies cannot introduce significant effect on intensification of heat transfer within the solar absorber, shall be stated. This is influenced primarily by high viscosity of the circulating fluid (approximately 120 times greater than the viscosity of water at the ambient temperature [24]), resulting in creation of large viscous boundary layer at the absorber-fluid interface, as well as low range of the frequencies assumed for the simulation [23].…”

Section: Resultsmentioning

confidence: 99%

“…However, the investigations has not considered utilization of vibrating elements to enhance the heat transfer due to turbulization of the flow of external circulating medium. Although considerably positive effect of vibrations on heat dissipation has been investigated and discussed [22,23], its applicability within the solar thermal collectors has not be investigated yet.…”

Section: Introductionmentioning

confidence: 99%

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Modeling of influence of vibration on intensification of heat transfer within the absorber of the vacuum solar collector

et al. 2019

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Due to escalating role of mitigation of climate change in power and energy sector, power units based on renewable energy sources (RES) became vital part of global power and heat market, including distributed heat generation as well. Significant number of such installations belong to individual users, commonly using solar collectors to prepare domestic hot water directly at their sites. However, the vitally variable solar irradiance makes the solar energy difficult in efficient harvesting considering long time period. Thus, maximization of power gain from single solar absorber, when the solar radiation flux is temporarily high, might lead to further rise in overall, year-averaged efficiency of such units. The paper concerns modelling of intensification of heat transfer, taking place within the absorber of a vacuum solar collector, due to insertion of vibrating element inside the thermal oil canal, compared to static turbulization method. Different geometries of vibrating elements and amplitudes of oscillatory motion, as well as heat carriers, are investigated using commercially available CFD software. Results indicate rise in solar power acquired within the absorber using vibrating elements, with essential difference between circulating media, and suggest vital benefits from utilization of static turbulizing devices.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modeling of influence of vibration on intensification of heat transfer within the absorber of the vacuum solar collector

et al. 2019

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“…An exhaustive review of the performance enhancement criterion, as an effective tool for measuring heat and fluid flow characteristics, was provided by Yilmaz et al [34]. The PEC has also been indexed in several heat transfer applications [35][36][37][38]. In the context of heat transfer through jet impingement, the thermal-hydraulic performance evaluation was also carried out using the PEC by Choi et al [32].…”

Section: Target Surface Shape and Spacing Between Jet Plate/nozzle And Target Surfacementioning

confidence: 99%

Heat Transfer Augmentation through Different Jet Impingement Techniques: A State-of-the-Art Review

et al. 2021

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Jet impingement is considered to be an effective technique to enhance the heat transfer rate, and it finds many applications in the scientific and industrial horizons. The objective of this paper is to summarize heat transfer enhancement through different jet impingement methods and provide a platform for identifying the scope for future work. This study reviews various experimental and numerical studies of jet impingement methods for thermal-hydraulic improvement of heat transfer surfaces. The jet impingement methods considered in the present work include shapes of the target surface, the jet/nozzle–target surface distance, extended jet holes, nanofluids, and the use of phase change materials (PCMs). The present work also includes both single-jet and multiple-jet impingement studies for different industrial applications.

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“…Active and passive techniques are the two main methods for heat transfer enhancement. The active techniques, such as using ultrasonic vibration [2] and magnetic fields [3][4][5], need external power. The passive techniques, such as tube inserts [6,7], turbulators [8], vortex generators [9][10][11] and special shaped tubes [12][13][14], can induce strong secondary flow, which has been proven to be beneficial to heat transfer [15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Heat Transfer Enhancement in a Novel Annular Tube with Outer Straight and Inner Twisted Oval Tubes

Luo,

Song,

Tagawa

et al. 2020

Symmetry

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The thermal-hydraulic performance in a novel annular tube formed by outer straight and inner twisted oval tubes is numerically investigated. An annular tube formed by two straight oval tubes is also studied for comparison. Inner twisted oval tubes with different aspect ratios and twist ratios are studied. The heat transfer is well improved by the symmetrical secondary flow in the annulus. The Nusselt number generally increases when the inner oval tube becomes flatter and the twists stronger in the studied range of geometrical parameters. The largest Nusselt number Nu of the inner twisted tube increases by 116% while the friction factor f increases by only 46% compared with that of the inner straight tube, and the largest value of the thermal performance factor (JF) can be up to 1.9. Correlations of the Nusselt number and friction factor are proposed for laminar and turbulent flows, and the deviations of the correlations are within ±5% and ±4% for Nu and f, respectively.

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Experimental and numerical study on heat transfer enhancement using ultrasonic vibration in a double-pipe heat exchanger

Cited by 85 publications

References 38 publications

Modeling of influence of vibration on intensification of heat transfer within the absorber of the vacuum solar collector

Modeling of influence of vibration on intensification of heat transfer within the absorber of the vacuum solar collector

Heat Transfer Augmentation through Different Jet Impingement Techniques: A State-of-the-Art Review

Heat Transfer Enhancement in a Novel Annular Tube with Outer Straight and Inner Twisted Oval Tubes

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