Numerical Investigation on Heat Transfer and Hydraulic Performance of Al2O3-Water Nanofluid as a Function of Reynolds Number and Flow Velocity (original) (raw)
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Chemical Product and Process Modeling, 2017
This research presents the numerical results of laminar forced convective heat transfer performance and the flow behaviour for Al 2 O 3-water nanofluid in circular, 2:1 rectangular, 4:1 rectangular and square ducts. The nanoparticles concentration studied were 0.01%, 0.09%, 0.13%, 0.25%, 0.51%, 1.00% and 4.00%. Single phase constant and temperature-dependent properties were employed. For the case of constant properties, the thermal performance and pressure drop increase with the increase of nanofluid concentration and Reynolds number. For the temperature-dependent properties, the Nusselt number and pressure drop also increase when the Reynolds number increases. However, there is a slight decrement in the Nusselt number and no significant pressure drop increment when the nanofluid concentration is increased from 0.01% to 1.00%. When the concentration is further increased to 4.00%, the Nusselt number and pressure drop increase. For the temperature-dependent model, lower thermal performance and pressure drop are identified when compared to those of the constant properties. The maximum Nusselt number enhancement and pressure drop increment occur at the concentration of 4.00% and Reynolds number of 2000. They are 25.43% and 945.69% as well as 4.86% and 117.01% for constant and temperature-dependent properties, respectively. The thermal-hydraulic efficiency of nanofluid is found to be not as good as the pure water.
Iraqi Journal of Industrial Research, 2024
The use of advanced nanofluids increases and improves the heat transfer process in different industrial and engineering applications compared to conventional fluids. In recent years, researchers have used in their research investigations the addition of nanofluids with the basic fluid to improve its thermophysical properties. This research deals with a numerical study (simulation using commercial CFD code) of forced convection heat transfer in a two-dimensional (2D) pipe by adding aluminum oxide (Al 2 O 3 ) as a nanofluid with water (H 2 O) and by partially constant heat flux along the length of the pipe and in the direction of the axis of fluid flow. Several operational parameters have been studied, including the heat transfer coefficient, the Nusselt number, the friction factor, and the pressure difference as a function of the Reynolds number, as well as studying the temperature distribution, velocity, and pressure of fluid flow inside the test section. Reynolds number range of fluid flow (3000 -6000) with volumetric fractions of nanofluids at (0.6% and 1.5%). The results of the study showed the addition of nanofluid with water improves and increases the heat transfer coefficient and thus increases the Nusselt number, also the friction factor gradually decreases by increasing the velocity of the fluid passing into the pipe.
Experimental Thermal and Fluid Science, 2013
This article presents the heat transfer coefficient and friction factor of the nanofluids flowing in a horizontal tube under laminar flow conditions, experimentally. The experiments have been done on fully developed region under the constant wall temperature condition. Al 2 O 3 nanoparticles with diameters of 40 nm dispersed in distilled water with volume concentrations of 0.1-2 vol.% were used as the test fluid. All physical properties of the Al 2 O 3-water nanofluids needed to calculate the pressure drop and the convective heat transfer coefficient have been measured. The results show that the heat transfer coefficient of nanofluid is higher than that of the base fluid and increased with increasing the Reynolds number and particle concentrations. The heat transfer coefficient increases by approximately 32% in the fully developed region at 2 vol.% nanofluid. The measured pressure loss for the nanofluids was in general much higher than for pure water. The experimental results illustrate that the single phase correlation with nanofluids properties could not predict heat transfer coefficient enhancement of nanofluids fairly.
A Cfd Study Of Heat Transfer Enhancement In Pipe Flow With Al2O3 Nanofluid
2011
Fluids are used for heat transfer in many engineering equipments. Water, ethylene glycol and propylene glycol are some of the common heat transfer fluids. Over the years, in an attempt to reduce the size of the equipment and/or efficiency of the process, various techniques have been employed to improve the heat transfer rate of these fluids. Surface modification, use of inserts and increased fluid velocity are some examples of heat transfer enhancement techniques. Addition of milli or micro sized particles to the heat transfer fluid is another way of improving heat transfer rate. Though this looks simple, this method has practical problems such as high pressure loss, clogging and erosion of the material of construction. These problems can be overcome by using nanofluids, which is a dispersion of nanosized particles in a base fluid. Nanoparticles increase the thermal conductivity of the base fluid manifold which in turn increases the heat transfer rate. In this work, the heat transfe...
Ain Shams Engineering Journal, 2015
In this study, the flow field and heat transfer of Al 2 O 3 -water nanofluid turbulent forced convection in a tube are investigated. The surface of the tube is hot (T h = 310 K). Simulations are carried out for constant water Prandtl number of 6.13, Reynolds numbers from 10,000, 20,000, 30,000 to 100,000, nanoparticles volume fractions of 0, 0.001, 0.1, 0.2, 0.4 and nanoparticles' diameter of 25, 33, 75, and 100 nm. The finite volume method and SIMPLE algorithm are utilized to solve the governing equations numerically. The numerical results showed that with enhancing Reynolds numbers, average Nusselt number increases. The variations of the average Nusselt number relative to volume fractions are not uniform. For all of the considered volume fractions, by increasing the Reynolds number the skin friction factor decreases and with increasing volume fractions and Reynolds number the pressure drop increases.
International Conference on Mechanical, Industrial and Energy Engineering 2018 23-24 December, 2018, Khulna, BANGLADESH , 2018
The Numerical study of laminar convective heat transfer of aluminum oxide (Al 2 O 3)-water nanofluid for the developed region through a plain tube is presented. The second order single phase energy equation, mass and momentum equation are solved by using finite volume method with the ANSYS FLUENT 16 software. The plain pipe's diameter is 5mm and length is 750mm. Aluminum oxide (Al 2 O 3) nanoparticles with different volume fraction (1%-5%) using with water which is considered as the base fluid are analyzed for a range of Reynolds number from 100 to 1400 at constant heat flux 500 W/m 2 at the tube wall. The result revels that for increasing the Reynolds number the Nusselt number and heat transfer coefficient are increased linearly and friction factor decreased linearly in the developed region for both water and Al 2 O 3-H 2 O nanofluid. At constant Reynolds number, by increasing the volume fraction of Al 2 O 3 nanoperticles from 1% to 5% the value of Nusselt number increased rapidly from 0.27% to 15%, heat transfer coefficient increased 7.2% to 31.5% and friction factor increased very little from 0.1% to 2%.
Proceedings of the 3rd International Conference of Fluid Flow, Heat and Mass Transfer (FFHMT'16), 2016
In the present paper, laminar and turbulent forced convection flows in a horizontal pipe with Al 2 O 3-water nanofluid are considered numerically. A single phase model formulation is used for comparison with the mixture model. Temperature-dependent fluid properties are taken into account for all cases. The heat transfer coefficients computed with the mixture model showed a better agreement with experimental data reported in the literature as compared to the single phase model. Temperature-dependent fluid properties result in a better prediction of the thermal field under the effect of a constant heat flux, whereas calculations with constant fluid properties result in an over prediction of the heat transfer coefficient. The results are presented and discussed for six values of the Reynolds number covering the laminar and turbulent flow regimes and four values of the concentration in nanoparticles within the range 0≤ϕ≤2%.
8TH BSME INTERNATIONAL CONFERENCE ON THERMAL ENGINEERING
A numerical analysis of laminar convective heat transfer of aluminum oxide (Al 2 O 3)-water Nanofluid for the developed region through two parallel plates are presented in this present work. The second order single phase energy equation, mass and momentum equation are solved by using finite volume method with the ANSYS FLUENT 16 software. The distance between two parallel plates is 4mm and length is 600mm. The study is done for a water based nanofluid with 1% to 5% volume concentration of Al 2 O 3 for a range of Reynolds number of 500 to 1100 at constant heat flux 500 W/m 2 at the channel walls. The result revels that for increasing the Reynolds number the Nusselt number and heat transfer coefficient are increased linearly and friction factor decreased linearly in the developed region for both water and Al 2 O 3-H 2 O nanofluid. By increasing the volume fraction of Al 2 O 3-H 2 O nanofluid from 1% to 5% the value of Nusselt number increased rapidly from 0.7% to 7.32%, heat transfer coefficient increased 7.14% to 31.5% and friction factor increased very little from 0.1% to 4% for constant Reynolds number compared to pure water. At constant heat transfer coefficient 700 W/m 2-K the pumping power advantages has been achieved 20% for 1% volume concentration and 62% for 3% volume concentration of nanofluid compared to pure water.
Kufa Journal of Engineering, 2020
A two-dimensional numerical investigation on laminar forced convection is carried out to estimate the thermal and fluid field behavior of Al2O3-water nanofluid in a circular pipe with constant heat flux. In this study, the finite element method (FEM) is employed to analyze the continuity, momentum, and energy governing equations by using COMSOL Multiphysics 3.5a. Computations of heat transfer rates were performed for a range of Reynolds numbers (Re ≤ 2000), and (Pr= 5.42). The effects of Reynolds number and fraction volume of nanoparticle (ɸ≤ 5%) on the mean coefficient of convection (havg), pressure drop (∆P), and thermal-hydraulic performance are investigated. The computations indicate that Al2O3 nanoparticle usage augments the average coefficient of heat convection significantly, and which is increased by (10%) with maximum pressure loss (15%) for (ɸ=5%) and high Reynolds number when compared to the base fluid. The present model is validated with empirical Shah Equation and the r...
2017
In the present research, the laminar forced convective heat transfer and fluid flow characteristics for Al2O3-water nanofluid flowing in different bend (i.e., 180o and 90o) pipes have been investigated numerically in a three-dimensional computational domain using the finite volume technique. The effects of different pertinent parameters, such as the Reynolds number of the duct, volume fraction of the nanoparticle, the diameter of the nanoparticle, aspect ratio of the duct and the duct bend angle on the hydrodynamic and thermal characteristics of the flow has been presented. It is observed that the heat transfer is augmented by replacing conventional fluid by Al2O3-water nanofluid. The nanoparticle volume fraction is found to be an important parameter to increase the heat transfer in the bend pipe. It is also observed that the thermo-hydraulic characteristics of the flow changes with the duct aspect ratio, and the heat transfer rate is improved with aspect ratio. The heat transfer wi...