Investigation of effect of the circular ring turbulators on heat transfer augmentation and fluid flow characteristic of solar air heater

Acır, Adem; Ata, İsmail; Canlı, Mehmet Emin

doi:10.1016/j.expthermflusci.2016.04.012

Cited by 41 publications

(10 citation statements)

References 23 publications

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“…The thermo-hydraulic effectiveness (ε) of the collector, introduced by Webb and Eckert [29], is another thermo-hydraulic performance parameter, which is not dependent on any collector-independent parameter; it takes into account both increased heat transfer and friction losses of an artificially roughened absorber and, for the same pumping power, relates these values to those of a smooth absorber [2,11,15,20,[30][31][32][33][34][35]:…”

Section: Thermo-hydraulic Effectivenessmentioning

confidence: 99%

“…For example, when Re = 9000, ε max = 2.9, 1.6, 1.4, and 0.5 for the absorbers investigated, respectively, by Chamoli et al [51], Kumar and Layek [28], Chauhan and Thakur [50], and Gawande et al [27]. Finally, it is worth mentioning that some modeling works, also developed during the last decade for different roughness types, were not analyzed herein, mainly because the experimental setup deviates considerably from the typical configuration of a rectangular duct with a single rough surface: Skullong and Promvonge [30] used triangle-shaped winglets to enhance the roughness of a collector having two absorber plates; Tamna et al [32] investigated the effect of multiple thin V-shaped ribs attached to the absorber surfaces of a double-absorber collector; Skullong et al [31] investigated the effect of absorbers with multiple V-shaped ribs, interspersed with straight grooves, oriented perpendicular to the flow direction, in a double-absorber collector; Acır et al [33] investigated round-duct collectors containing inner ring-shaped plates with holes, perpendicular to the flow direction, to increase the turbulence of the air stream; Kumar et al [35] studied the effect of straight ribs, perpendicular to the flow direction, attached to the absorber of a collector made of a triangle-shaped cross-section duct.…”

Section: Other Obstacle Typesmentioning

confidence: 99%

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Thermo-Hydraulic Performance of Solar Air Collectors with Artificially Roughened Absorbers: A Comparative Review of Semi-Empirical Models

Araújo¹

2020

Energies

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Due to the poor thermal characteristics of the air, the absorber roughness of solar air collectors is commonly artificially increased in order to enhance the heat transfer to the air stream. However, this is also accompanied by an undesirable increase in the pumping power due to increased friction losses. As a result, several authors have experimentally investigated several ways of maximizing the heat transfer while minimizing the friction losses of different absorbers, resulting in the development of semi-empirical functions relating the Nusselt number (a measure of heat transfer) and the friction factor (a measure of friction losses) to the Reynolds number and the roughness parameters considered for each absorber. The present paper reviews, considering the publications from the last ten years, these semi-empirical functions. Moreover, the optimum roughness parameters and operating conditions of the absorbers were estimated by finding the maximum values of two performance parameters (the thermo-hydraulic efficiency and effectiveness), calculated using the semi-empirical functions, in order to classify the absorbers in terms of their energy characteristics. This approach proves to be a rather effective way of optimizing the roughness characteristics of solar air collector absorbers. It is also concluded that, considering the range of absorbers analyzed here, generally, multiple V-shaped ribs with gaps provide the most effective roughness geometry.

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Section: Thermo-hydraulic Effectivenessmentioning

confidence: 99%

Section: Other Obstacle Typesmentioning

confidence: 99%

Thermo-Hydraulic Performance of Solar Air Collectors with Artificially Roughened Absorbers: A Comparative Review of Semi-Empirical Models

Araújo¹

2020

Energies

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“…Hans et al [25] executed the broken arc rib roughness geometry on the absorber plate which influenced better performance than nil roughness geometry. Adem et al [26] investigated circular ring turbulators with various hole geometries on the absorber plate of the solar air collector.…”

Section: Introduction and Literature Reviewsmentioning

confidence: 99%

Performance Analysis of Red Chilli in a Hybrid Collector with Solar Dryer

Murali¹

2021

TURCOMAT

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This article performed various analysis on Red chilli by hybrid collector with solar dryer (HCSD). This study was carried out forced convection solar dryer which performed better in all aspects such as drying time, moisture removal rate, electrical efficiency, electrical thermal efficiency, thermal efficiency and overall thermal efficiency. In general, solar radiation was provided a sources of generating energy to drive a solar dryer. Hybrid collector has been provided the electrical and thermal energy to run a solar dryer. The solar dryer was tested by drying 12 kg of red chilli in the drying air temperature in the range of 32 0C – 56 0C. The initial moisture content of the red chilli was 71.5 % (weight basis) and was reduced to the final moisture content of 16.2 % (weight basis) in 6 consistent days with clear sunny days. The HCSD was operated between 9 hrs to 16 hrs. Finally, comparative study was also handled for better understanding in HCSD, in which solar dryer drying made better outcome than open sun drying.

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“…Acir et al. 26 improved the heat transfer rate of solar air collectors by 229% using perforated circular rings with increase in friction factor by 5.8 times compared flat absorber. Similarly, Nayak and Singh 27 reported that, the JISAC has high energy efficiency due to improved convective heat transfer coefficient.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigations on jet impingement solar air collectors using pin-fin absorber

Kannan¹,

Mohanraj

Sathyabalan³

2020

Proceedings of the Institution of Mechanical Engineers, Part E:

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In this paper, the performances of a novel jet impingement solar air collector (JISAC) using flat and pin-fin absorbers were experimentally investigated. The experimental observations in a JISAC have been made under the climatic conditions of Coimbatore city in India during the year 2019. The thermo-hydraulic analyses were conduced to study the influence of pressure drop across the perforated jet plate. The effects of solar irradiation, ambient temperature, ambient wind velocity and air mass flow rate through the JISAC duct using flat and pin-fin absorbers were studied. The air mass flow rate through the JISAC was optimized to 0.025 kg/s based on the experimental trials. Thermodynamic performance comparisons have been made among the flat and pin-fin absorbers. The results showed that, the JISAC using pin-fin absorber has 2–7°C higher air temperature at the outlet with 3–7%, 2–6% and 2–6% improved energy efficiency, thermo-hydraulic efficiency and exergy efficiency, respectively when compared to the JISAC using flat absorber. The pressure drop across the JISAC duct is about 90% higher when compared to the conventional solar air collectors. The pressure drop through the jet plate has increased the air velocity impinging on the absorber. As a result, the heat transfer coefficient between air and the absorber has been significantly improved.

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Investigation of effect of the circular ring turbulators on heat transfer augmentation and fluid flow characteristic of solar air heater

Cited by 41 publications

References 23 publications

Thermo-Hydraulic Performance of Solar Air Collectors with Artificially Roughened Absorbers: A Comparative Review of Semi-Empirical Models

Thermo-Hydraulic Performance of Solar Air Collectors with Artificially Roughened Absorbers: A Comparative Review of Semi-Empirical Models

Performance Analysis of Red Chilli in a Hybrid Collector with Solar Dryer

Experimental investigations on jet impingement solar air collectors using pin-fin absorber

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