Performance analysis of solar air heater using triangular corrugated absorber under jet impingement

ABSTRACT

Solar air heaters (SAHs) are one of the most basic forms of solar thermal energy conversion devices. In this study, a numerical analysis has been done to investigate the thermo-hydraulic characteristics of triangular and sinusoidal corrugated absorbers under jet impingement, using CFD code on ANSYS (Fluent) 2022-R1 software. The jet impingement techniques can boost the efficiency of SAHs. The impact of different corrugation depths (d = 3, 4, 5, 6, and 7 mm) and pitch (P = 12.5, 25, 50, 75, and 100 mm) on thermohydraulic characteristics of corrugated absorber under jet impingement was studied. The range of Reynolds number varies from 3500 to 15,500 at the main entrance of the duct. The results obtained from the comparison of triangular and sinusoidal corrugated absorbers are also discussed. The optimum HT was obtained at a corrugation depth of 4 mm and a pitch of 50 mm. The friction factor reaches its peak at 7 mm depth and 12.5 mm pitch of corrugation. The highest thermohydraulic performance factor (TPF) achieved about 1.85 for 4 mm depth and 50 mm pitch of corrugation at an Re of 3500. As per the findings, HT is enhanced by the triangular corrugated absorber as compared to the sinusoidal corrugated absorber surface.

KEYWORDS:

• Solar air heater
• CFD
• Jet impingement
• Triangular corrugated absorber
• Heat transfer
• Thermohydraulic performance

Nomenclature

SAH	=	Solar air heater
HT	=	Heat transfer
q	=	Heat flux (W)
$\dot{m}$	=	Mass flow rate (Kg/s)
$\mathrm{\Delta }P$	=	Pressure drops through the test section
k	=	Thermal conductivity (W/mK)
$C_p$	=	Specific heat capacity (KJ/kgK)
v	=	Air velocity (m/s)
Re	=	Reynolds number
Nu	=	Nusselt number
f	=	Friction factor
TPF	=	Thermohydraulic performance factor
St	=	Stanton number
L	=	Length of duct
jh	=	Colburn j factor
Pr	=	Prandtl number
$L_1$	=	Length of the test section
$L_2$	=	Length of the outlet section
W	=	Width of duct
H	=	Height of duct
Dh	=	Hydraulic diameter
Dj	=	Diameter of jet
Hj	=	Height of jet
Dj/Dh	=	Jet diameter ratio
Dj/Dh	=	Jet height ratio
X/Dh,Y/Dh	=	Streamwise and spanwise pitch ratio
P	=	Corrugated pitch
d	=	Corrugated depth
Greek Symbols	=
$\mu$	=	Dynamic viscosity (kg/ms)
P	=	Density (kg/m3)

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Notes on contributors

Nitesh Kumar Jasyal

Mr. Nitesh Kumar Jasyal Area of Research: Numerical analysis of solar air heater with jet impingement under corrugated absorber plate. Nitesh Kumar Jasyal is an M.Tech scholar in the Mechanical Engineering Department at National Institute of Technology Hamirpur, H.P., India. He graduated from Jai Parkash Mukand Lal Innovative Engineering and Technology Institute (JMIETI) in 2018. His research interests include the Numerical analysis of solar air heaters with jet impingement under corrugated absorber plates.

Sohan Lal Sharma

Mr. Sohan Lal Sharma Area of Interest: Thermal Engineering, Heat Transfer, Solar air heater, CFD, TEG/TEC, and Thermal Energy Storage Systems. Sohan Lal Sharma is a Ph.D. research scholar in the Mechanical Engineering Department at National Institute of Technology, Hamirpur, H.P., India. He obtained his B. Tech degree in Mechanical Engineering from Beehive College of Engineering and Technology, Selaqui, Dehradun, U.K., India in 2015 and M.Tech degree in Thermal Engineering from Bipin Tripathi Kumaon Institute of Technology, Dwarahat, Almora, U.K., India (Formerly Kumaon Engineering College Dwarahat) an Autonomous Institute of Govt. of Uttarakhand in 2018. He is currently working on experimental and numerical analysis of heat transfer enhancement in solar Aar heaters.Google Scholar Link:https://scholar.google.com/citations?user=bMLhGEIAAAAJ&hl=enResearch Gate Link: https://www.researchgate.net/profile/Sohan-Sharma-2

Ajoy Debbarma

Dr. Ajoy Debbarma Area of Interest: Thermal Engineering, Heat Transfer, Jet Impingement Cooling, Solar air heaters, BTMS, Energy conversion system. Dr. Ajoy Debbarma is an Assistant Professor in the Department of Mechanical Engineering at National Institute of Technology Hamirpur, H.P., India since 2018. He received his Ph.D. degree in Mechanical Engineering from National Institute of Technology Silchar, Assam, India in 2017, M.Tech degree from the same institute in the year of 2013, and his bachelor’s degree from Tripura Institute of Technology, Narsingarh, Agartala Aerodrome, Tripura (West), India in the year of 2011. His research interests include Thermal Engineering, Heat Transfer, Jet Impingement Cooling, Solar air heaters, BTMS, and Energy conversion systems.Google Scholar Link: https://scholar.google.com/citations?user=dRv72MIAAAAJ&hl=en&authuser=1&oi=ao