Hydrothermal performance of mini-channel heat sink using nanofluids/hybrid nanofluids: A numerical study

ABSTRACT

We investigated hydrothermal performance of the mini-channel heat sink by using water, and nanofluids/hybrid nanofluids at 1% of volumetric concentration. The water-based nanofluids studied in this work were CuO, TiO₂ and Fe₂O₃ with CuO-TiO₂ and CuO-Fe₂O₃ hybrid combinations. The mean diameter of all the nanoparticles was fixed to be 60 nm. For numerical modeling, multiphase mixture model was used. The maximum heat transfer recorded for CuO and (CuO .75%+ Fe₂O₃ .25%) based nanofluids was 59.12W and 58.27 W, respectively, at maximum Reynolds number of 1750. The maximum percentage increment in heat transfer recorded for CuO and hybrid (CuO .75%+Fe₂O₃ .25%) water-based nanofluids was 29.24% and 24.55%, respectively, then water at minimum Reynolds number of 750. Results are evaluated in the form of the base temperature, thermal resistance, heat transfer, pressure drop and Nusselt number. The minimum base temperature was recorded for CuO-H₂O as 35.4 at maximum Reynold number (Re) of 1750 among all the nanofluids/hybrid nanofluids. However, maximum percentage reduction in the base temperature was recorded for CuO-H₂O as 7.04% compared with water at minimum Reynolds number of 750. It was observed that nanofluids lead toward high heat transfer.

KEYWORDS:

• Hybrid nanofluids
• CuO-Fe₂O₃
• CuO-TiO₂
• thermal management
• mini-channel

Disclosure statement

No potential conflict of interest was reported by the author(s).

Nomenclature

Lf	=	= Length of the fin in mm
hf	=	= height of the fin in mm
wf	=	= width of fin in mm
hfd	=	= height of the fluid domain in mm
wfd	=	= width of the fluid domain in mm
ρ	=	= Density in kg/m3
Cp	=	= Specific heat in kJ/kg0K
k	=	= Thermal conductivity in (W/mK)
$\dot{\mathrm{Q}}$	=	= Heat transfer in W
ṁ	=	= Mass flow rate in kg/s
Cnf	=	=Specific heat of nanofluids (kJ/kg K)
To	=	= Outlet fluid temperature in0C
Ti	=	= Inlet fluid temperature in0C
LMTD	=	= Log of mean temperature difference in0C
Tb	=	= Temperature at the base in0C
Rth	=	= Thermal resistance in0C/W
Aact	=	= Actual area in m2
Re	=	= Reynolds number
$U_{\mathit{in}}$	=	= Velocity at the inlet in (m/s)
h	=	= Convective heat transfer in (W/m2K)
Nu	=	= Nusselt number
$\mathrm{\Delta }\mathit{P}$	=	= Pressure drop in (Pa)
Dh	=	= Hydraulic diameter in (m)
$C_{\mathit{peff}}$	=	= Effective specific heat capacity for nanofluids/hybrid nanofluids in (kJ/kg K)
$C_{\mathit{pnp}}$	=	= Specific heat capacity for nano particle in (kJ/kg K)
$C_{\mathit{pbf}}$	=	= Specific heat capacity for base fluid in (kJ/kg K)
$k_{\mathit{eff}}$	=	= Effective thermal conductivity for nanofluids/hybrid nanofluids in (W/mK)
kbf	=	=Thermal conductivity for base-fluids in (W/mK)
knp	=	=Thermal conductivity for nanoparticles in (W/mK)
W	=	= Width of the heat sink in (mm)
Greek symbol	=
${\rho }_{\mathit{eff}}$	=	= Density for hybrid, (kg/m3)
${\rho }_{\mathit{np}}$	=	= Density for nano particle, (kg/m3)
${\rho }_{\mathit{bf}}$	=	= Density for the base fluid, (kg/m3)
µef	=	=Effective viscosity for Hybrid (kgm/s)
µnp	=	= Viscosity for base fluid (kgm/s)
µbf	=	= Viscosity for base fluid (kgm/s)
${\mathrm{\varnothing }}_{\mathit{np}}$	=	= Volumetric fraction of nano particles

Additional information

Notes on contributors

Taha Baig

Taha Baig, a research assistant at the School of Professional Education & Executive Development, The Hong Kong Polytechnic University, Kowloon, holds a bachelor’s degree in mechanical engineering from the University of Wah, Pakistan, and a Master’s in Thermal System Engineering from the University of Engineering and Technology Taxila, Pakistan. His research interests include electronic cooling, nanofluids, and computational fluid dynamics. During his tenure at different universities in his native country, he imparted theoretical and practical courses to undergraduate students.

Hussain Ahmed Tariq

Hussain Ahmed Tariq graduated as a Mechanical Engineer from HITEC University, Pakistan. Following his bachelor’s degree, he pursued a master’s degree in mechanical engineering, with specialization in Fluid and Thermal Systems, at the Institute of Space Technology, Pakistan. His major work includes the improvements of electronics cooling and contributed numerous research articles to ISI-indexed impact factor Journals. His research interest is in heat transfer, thermal systems, and sustainable energy. Additionally, he also had the opportunity to work in a university in his native country where he taught several theoretical and practical courses to undergraduate students.

Muhammad Anwar

Dr. Muhammad Anwar, currently working as an assistant professor in the Department of Mechanical Engineering at institute of Space Technology, Islamabad, Pakistan. He received his doctoral degree from Faculty of Science, Technology and Medicine, University of Luxembourg, in 2014. He worked as research associate at University of Luxembourg and then research fellow at University of Nottingham, UK. Heat transfer enhancement, renewable energy and phase transitions are his major areas of interest. Over the span of several years, he supervised numerous undergraduate and postgraduate students and his work produced more than 25 papers featured in various reputed international journals. His other research interests include electrical and electronics cooling systems, nanofluids, phase change materials, and thermal management of electronic circuitry.

Ahmad Adnan Shoukat

Ahmad Adnan Shoukat is a versatile Mechanical Engineer with a multidisciplinary focus. His expertise extends to the intricate design of Heat Exchangers as a Static Equipment Design Engineer, while his Ph.D. candidacy in Biomedical Engineering at Istanbul Medipol University, showcases a diverse skill set, emphasizing the enhancement of nanofibers for health monitoring applications.

Hafiz Muhammad Ali

Dr. Hafiz Muhammad Ali is currently working as an associate professor and director of renewable energy laboratory at Mechanical Engineering Department of King Fahd University of Petroleum and Minerals, Saudi Arabia. He holds a doctoral degree in mechanical engineering from School of Engineering and Materials Science, Queen Mary University of London, UK. Dr. Ali was a postdoc at Water and Energy Laboratory of University of California at Merced, United States.

Muhammad Mansoor Janjua

Dr. Muhammad Mansoor Janjua is currently working as an associate professor in Higher Colleges of Technology at Dubai, UAE. He is a highly skilled Mechanical Engineer with strong technical, analytical and research skills. Strengths include a firm background in Design, Analysis, Fluid Mechanics, Heat Transfer and Mechanics. Detail driven with proven leadership abilities and outstanding interpersonal and organizational skills.