Laminar convective heat transfer of Al2O3/water nanofluid through square cross-sectional duct (original) (raw)

Numerical investigation of Al2O3/water nanofluid laminar convective heat transfer through triangular ducts

Nanoscale Research Letters, 2011

In this article, laminar flow-forced convective heat transfer of Al2O3/water nanofluid in a triangular duct under constant wall temperature condition is investigated numerically. In this investigation, the effects of parameters, such as nanoparticles diameter, concentration, and Reynolds number on the enhancement of nanofluids heat transfer is studied. Besides, the comparison between nanofluid and pure fluid heat transfer is achieved in

Numerical Studies on the Laminar Thermal-Hydraulic Efficiency of Water-Based Al2O3 Nanofluid in Circular and Non-Circular Ducts

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.

Experimental investigation of laminar convective heat transfer and pressure drop of water-based Al2O3 nanofluids in fully developed flow regime

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.

Fluid flow and heat transfer characteristics in a curved rectangular duct using Al2O3-water nanofluid

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...

Mechanism of Forced Convective Heat Transfer in Al 2 O 3 / Water Nanofluid under Laminar and Turbulent Flow

2012

In this paper, fully developed laminar and turbulent flow convective heat transfer characteristics of Al2O3/water nanofluid flowing through a uniformly heated horizontal tube with and without wire coil inserts is presented. For this purpose, Al2O3 nanoparticles of 43 nm size were synthesized, characterized and dispersed in distilled water to formulate Al2O3/water nanofluid containing 0.1, 0.15 and 0.2% volume concentration of nanoparticles. Two wire coil inserts made of stainless steel with pitch ratios 2 and 3 were used. The results provide experimental evidence that the mechanism of thermophoresis play a pivotal role in explaining the heat transfer enhancement observed with nanofluids. Keywords— Heat transfer enhancements, Nusselt number, Nanofluid, Wire coil insert.

Numerical Investigation in Augmentation of Heat Transfer in a Rectangular Duct Using Al2O3 and CuO Nanofluids

Asian Review of Mechanical Engineering

A numerical investigation was conducted to predict the greater thermal enhancement in the rectangular duct using different nanofluids – Aluminum oxide (Al2 O3) and Copper oxide (CuO) are employed in the investigation and magnitude are compared with base fluid to ascertain the augmentation of thermal efficiency. Ansys-Fluent 13 used for simulation to identify the augmentation of heat transfer among fluids. A simulation conducted in Laminar flow with Reynolds number (Re) ranges from 20 to 40 at constant heat flux 2000 W/m2. The research reported the contour of temperature distribution, pressure variation, and magnitude velocity, Result reveals that copper oxide nanofluids have produced significant thermal performances than other nanofluid particles.

New Effect Of Duct Cross Sectional Shape On The Nanofluid Flow Heat Transfer

2016

In the present article, we investigate experimental<br> laminar forced convective heat transfer specifications of TiO2/water<br> nanofluids through conduits with different cross sections. we check<br> the effects of different parameters such as cross sectional shape,<br> Reynolds number and concentration of nanoparticles in stable<br> suspension on increasing convective heat transfer by designing and<br> assembling of an experimental apparatus. The results demonstrate<br> adding a little amount of nanoparticles to the base fluid, improves<br> heat transfer behavior in conduits. Moreover, conduit with circular<br> cross-section has better performance compared to the square and<br> triangular cross sections. However, conduits with square and<br> triangular cross sections have more relative heat transfer enchantment<br> than conduit with circular cross section.

The study of laminar convective heat transfer of CuO/water nanofluid through an equilateral triangular duct at constant wall heat flux

Heat Transfer-Asian Research, 2012

The present paper focuses on the heat transfer of an equilateral triangular duct by employing the CuO/water nanofluid in a laminar flow and under constant heat flux condition. The triangular ducts were used due to their ease of creation and high compaction. They have less pressure drop when compared to the circular and non-circular ducts and their other attributes are very useful in industrial applications. These reasons cause their heat transfer characteristics to be very important. In this paper, to improve the heat transfer of an equilateral triangular duct, a CuO/water nanofluid was employed. The nanofluid was conducted through an equilateral triangular duct with a constant wall heat flux. Results show that the experimental heat transfer coefficient of the CuO/water nanofluid is more than that of distilled water. Also, the experimental heat transfer coefficient of a CuO/water nanofluid is greater than the theoretical one. The heat transfer enhancement of the equilateral triangular duct increases with the nanofluid volume concentration as well as the Peclet number. So a 41% enhancement in the convective heat transfer coefficient for a 0.8% CuO/water nanofluid can be seen when compared to pure water.

Study of laminar convective heat transfer, friction factor and pumping power advantage of Al2O3-water nanofluid through a channel

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.

The study of laminar convective heat transfer of CuO/water nanofluid through equilateral triangular duct at constant wall heat flux

Heat Transfer Asian Research, 2012

The present paper focuses on the heat transfer of an equilateral triangular duct by employing the CuO/water nanofluid in a laminar flow and under constant heat flux condition. The triangular ducts were used due to their ease of creation and high compaction. They have less pressure drop when compared to the circular and non-circular ducts and their other attributes are very useful in industrial applications. These reasons cause their heat transfer characteristics to be very important. In this paper, to improve the heat transfer of an equilateral triangular duct, a CuO/water nanofluid was employed. The nanofluid was conducted through an equilateral triangular duct with a constant wall heat flux. Results show that the experimental heat transfer coefficient of the CuO/water nanofluid is more than that of distilled water. Also, the experimental heat transfer coefficient of a CuO/water nanofluid is greater than the theoretical one. The heat transfer enhancement of the equilateral triangular duct increases with the nanofluid volume concentration as well as the Peclet number. So a 41% enhancement in the convective heat transfer coefficient for a 0.8% CuO/water nanofluid can be seen when compared to pure water.