Thermo-hydraulic performance analysis of a solar air heater (SAH) with quarter-circular ribs on the absorber plate: A comparative study

This experimental study on a solar air heater having absorber plate roughened artificially by providing roughness in the form of arc ribs having gap was carried out in the Department of Mechanical Engineering, Punjab Agricultural University, Ludhiana, India to study the effect of relative roughness pitch on thermal and thermohydraulic performance as well as to compare the performance of arc rib with gap roughened solar air heater with that of continuous arc rib roughened solar air heater. The roughness geometry parameters included relative roughness height of 0.043, angle of attack of 30 degree, relative gap position of 0.80, gap-width equal to the width of the rib and five values of relative roughness pitch ranging from 4 to 12 for flow Reynolds number range of 2000 to 16,000. The Nusselt number and friction factor were found to be more for relative roughness pitch value of 10 as compared to other values of relative roughness pitch. Thermo-hydraulic performance of solar air heaters roughened by arc with gap and continuous arc roughness geometries were found to be 1.91 times and 1.78 times respectively as compared to that of solar air heater having smooth absorber plate due to generation of turbulence in laminar sublayer region. However, improvement in thermo-hydraulic performance of solar air heater roughened by arc with gap geometry over continuous arc rib roughened solar air heater was attributed to generation of a region of turbulence on downstream side of the gap.

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Thermo-hydraulic performance analysis of jet plate solar air heater under cross flow condition

International Journal of Heat and Technology ◽

10.18280/ijht.350317 ◽

2017 ◽

Vol 35 (3) ◽

pp. 603-610

Author(s):

Prashil Vinod ◽

Shailendra Singh

Keyword(s):

Performance Analysis ◽

Flow Condition ◽

Cross Flow ◽

Hydraulic Performance ◽

Solar Air Heater ◽

Air Heater

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Thermal–hydraulic analysis of a solar air heater fitted with a wire-roughened absorber plate

Proceedings of the Institution of Mechanical Engineers Part E Journal of Process Mechanical Engineering ◽

10.1177/09544089211059044 ◽

2021 ◽

pp. 095440892110590

Author(s):

Nanjundappa Madhukeshwara ◽

A Alhadhrami ◽

Hassan A H Alzahrani ◽

B H Prasanna

Keyword(s):

Heat Transfer ◽

Friction Factor ◽

Efficiency Index ◽

Hydraulic Performance ◽

Index Formula ◽

Solar Air Heater ◽

Absorber Plate ◽

Air Heater ◽

Relative Roughness ◽

Nusselt Numbers

This study is to evaluate heat transmission and friction in a rectangular solar air heater with a V-shaped wire rib roughness on the absorber plate that operates in fully formed turbulent flow. Additionally, studies are performed to generate prediction equations for the average friction factor, Stanton number, and efficiency index. The Reynolds number [Formula: see text]–[Formula: see text], angle of attack [Formula: see text]20[Formula: see text]–90[Formula: see text]), relative roughness pitch [Formula: see text]–[Formula: see text], relative roughness height [Formula: see text]–[Formula: see text], and the aspect ratio [Formula: see text]–[Formula: see text] was varied. The efficiency index [Formula: see text] is commonly employed as a thermo-hydraulic performance metric. It is computed as [Formula: see text]. The wire roughness and airflow parameters [Formula: see text] are optimized to maximize heat transfer while retaining minimal friction losses. On the basis of resemblance criteria, average Stanton numbers, average Nusselt numbers, and even average friction factors are derived. The results are compared to those obtained with a smooth absorber duct under similar airflow circumstances in order to assess the increase in heat transfer coefficient and friction factor. The [Formula: see text], and [Formula: see text] have a significant influence on thermo–hydraulic performance, according to these studies. With [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text], the optimal configuration geometry for wire roughness and solar air heater duct is identified.

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