Experimental studies on the heat transfer characteristics of alumina/water nanofluid inside a helical coil tube
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ORIGINAL
Experimental studies on the heat transfer characteristics of alumina/water nanofluid inside a helical coil tube Mohsen Mansouri 1
&
Seyed Amir Hossein Zamzamian 1
Received: 21 September 2019 / Accepted: 29 September 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Laminar convective heat transfer and pressure drop characteristics of Al2O3-water nanofluid were experimentally investigated inside a horizontal Helical-Coil Tube (HCT) under constant heat flux boundary conditions for Dean numbers between 400 and 1600. The experiments have been performed using Al2O3-water nanofluid of three mass concentrations and heat fluxes at different flow rates. Thermal conductivity and viscosity of the fluids are measured experimentally, and a proper agreement was observed with the new model predictions for thermo-physical properties of nanofluids. Based on the experimental results, the thermal conductivity and viscosity of Al2O3-water nanofluid were almost 2.12% and 3.1% higher than water in 1 wt% concentration. According to the observations, the heat transfer coefficients in the fully developed region increases by 6.4%, 19%, and 23.7% under 2283, 3774, and 4975 W/m2 heat fluxes, respectively, at 1 wt% concentration of Al2O3-water nanofluid with respect to pure water. Besides, it has been noticed that pressure drop through the helical coil is increased with adding nanoparticles, enhancement of heat flux, and De number. Finally, based on the thermal performance factor, it has been concluded that using nanofluids in the helical coil is a feasible method for improving energy efficiency. Nomenclature ap Specific Area of Particle, (gr/m2) AC Alternating current Ag Silver Al Aluminium Al2O3 Aluminium Oxide C Correction Factor Cp Specific heat at constant pressure, (J/kg. K) Cpp Specific heat of Particle, (J/kg.K) CMC Carboxymethyl Cellulose Cu Copper CuO Copper Oxide D Coil diameter, m d Coil inside diameter, m dp Diameter of Nanoparticles, m De Dean number f Friction factor Fe2O3 Iron(III) oxide
* Mohsen Mansouri [email protected] * Seyed Amir Hossein Zamzamian [email protected] 1
Solar Energy Group, Energy Department, Materials and Energy Research Center (MERC), Karaj, Iran
H h h HCT K K Kp l ˙ m mm n nm Nu P P PANI PT q" R Rc r rp Re SDBS SiO2 T
Coil height, m Heat transfer coefficient Nano-layer Thickness Helical-Coil Tube Thermal conductivity, W/m2K Kelvin Thermal conductivity of Particles, W/m2K Coil length, m Mass flow rate, kg/s Millimetre Shape Factor Nanometre Nusselt number Pressure, Pa Perimeter, m Polyaniline Pitch Heat flux, W/m2 Dependent variable Radius of coil, m Radius of tube, m Radius of the Nanoparticles Reynolds number Sodium dodecyl benzene sulfonate Silicon dioxide Temperature, K
Heat Mass Transfer
U Average velocity, m/s VB Explainer of Brownian Velocity X Independent Variable Greek letters β Ratio of the Nanolayer Thickness η Thermal performance factor ρ Density, (kg/m3) ρp Particle Density, (kg/m3) μ Viscosity φ Volume fraction φm Mass percent ψ Spher
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