scholarly journals Numerical Prediction of Heat Transfer Characteristics of Nanofluids in a Minichannel Flow

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Arjumand Adil ◽  
Sonam Gupta ◽  
Pradyumna Ghosh
Keyword(s):  
Heat Transfer ◽  
Brownian Motion ◽  
Pressure Drop ◽  
Laminar Flow ◽  
Computational Model ◽  
Flow Regime ◽  
Cfd Simulation ◽  
Computational Results ◽  
Heat Transfer Characteristics ◽  
Simulation Process

CFD simulation of the heat transfer and pressure drop characteristics of different nanofluids in a minichannel flow has been explained using FLUENT version 6.3.26. Different nanofluids with nanoparticles of Al2O3, CuO, SiO2, and TiO2have been used in the simulation process. A comparison of the experimental and computational results has been made for the heat transfer and pressure drop characteristics for the case of Al2O3-water nanofluid for the laminar flow. Also, computations have been made by considering Brownian motion as well as without considering Brownian motion of the nanoparticles. After verification of the computational model with the experimental results for Al2O3-water nanofluid, the simulations were performed for the same experimental readings for different nanofluids in the laminar flow regime to find out the heat transfer and pressure drop characteristics.

Flow and Convective Heat Transfer Characteristics of Nanofluids With Various Shapes of Alumina Nanoparticles

2009 ◽  
Author(s):  
Kyo Sik Hwang ◽  
Hyo Jun Ha ◽  
Seung Hyun Lee ◽  
Hyun Jin Kim ◽  
Seok Pil Jang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Laminar Flow ◽  
Convective Heat Transfer ◽  
Flow Regime ◽  
Convective Heat ◽  
Circular Tube ◽  
Al2o3 Nanoparticles ◽  
Heat Transfer Characteristics ◽  
Laminar Flow Regime ◽  
Transfer Characteristics

This paper is to investigate flow and convective heat transfer characteristics of nanofluids with various shapes of Al2O3 nanoparticles flowing through a uniformly heated circular tube under fully developed laminar flow regime. For the purpose, Al2O3 nanofluids of 0.3 Vol.% with sphere, rod, platelet, blade and brick shapes are manufactured by a two-step method. Zeta potential as well as TEM image is experimentally obtained to examine suspension and dispersion characteristics of Al2O3 nanofluids with various shapes. To investigate flow characteristics, the pressure drop of Al2O3 nanofluids with various shapes are measured. In order to investigate convective heat transfer characteristics, the effective thermal conductivities of Al2O3 nanofluids with various shapes, the temperature distribution at the tube surface and the mean temperature of nanofluids at the inlet are measured, respectively. Based on the experimental results, the convective heat transfer coefficient of Al2O3 nanofluids with various shapes is compared with that of pure water and the thermal conductivity of Al2O3 nanofluids with various shapes. Thus, the effect of nanoparticles shape on the flow and convective heat transfer characteristics flowing through a uniformly heated circular tube under fully developed laminar flow regime is experimentally investigated.

CFD Study on Laminar Flow Pressure Drop and Heat Transfer Characteristics in Toroidal and Spiral Coil System

2004 ◽  
Author(s):  
Anthony J. Bowman ◽  
Hyunjae Park
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Laminar Flow ◽  
Heat Transfer Characteristics ◽  
Spiral Coil ◽  
Coil System ◽  
Transfer Characteristics ◽  
Flow Pressure ◽  
Toroidal Coil

Most pressure drop and heat transfer correlations obtained from the toroidal geometric system have been applied to the analysis of helical and spiral tube systems. While toroidal (and helical) coils have a constant radius of curvature about the coil center point (and center-line), spiral coils have a continuously varying radius of curvature, in which the varying centrifugal forces contribute to further enhance the heat transfer (at the cost of additional pressure drop) over toroidal and helical tube heat exchangers of the same length. Due to lack of published analytical, numerical and experimental data on spiral coil systems, in this paper, the laminar flow pressure drop and heat transfer characteristics of spiral coil systems are investigated with a commercially available CFD package (Fluent 6). First, an isothermal flow CFD analysis for a toroidal coil system is performed to optimally predict the local flow field and compared with the available experimental, numerical and analytical results, in which various model assumptions and operating conditions are involved. As a consequence, the heat transfer analysis with constant wall temperature boundary condition has been performed on a toroidal coil. With the verified CFD modeling schemes such as curved geometry creation, mesh/gird density control and solution model selection, the work is extended to the spiral coil system. The effects of Reynolds number and tube diameter to coil curvature ratio on the average friction factor and heat transfer characteristics are investigated for specified coil geometries utilizing water as the heat transfer medium. The general correlations for laminar flow pressure drop and heat transfer applied in a toroidal coil system are compared with the CFD results obtained from the spiral coil systems. It was found that up to 10% of the additional pressure drop and 40% of the enhanced heat transfer characteristics are obtained from the spiral coil system over the toroidal. The heat exchanger effectiveness ratio for spirals and toroids are compared for a range of Dean number. It was found that the spiral heat exchanger effectiveness ratio was between 20 to 30 percent greater than for general toroidal heat exchanger systems.

A 3-D Numerical Analysis of the Effect of Fin Pattern on the Thermo-Hydarulic Performance of Plate Heat Exchangers

2013 ◽  
Author(s):  
Kun-Hao Li ◽  
Chi-Chuan Wang
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Exchangers ◽  
Cfd Simulation ◽  
Flow Distribution ◽  
Heat Transfer Characteristics ◽  
Effective Surface ◽  
Plate Heat ◽  
Transfer Characteristics ◽  
Transfer Capability

This study numerically examines some commercially available plate patterns of plate heat exchangers using a 3-D CFD simulation. Detailed flow distribution and heat transfer characteristics subject to three different plate patterns are examined in this study. The plate pattern include GC26 and NT10 (double chevron) and SW26. The effective surface area of the associated plate patterns are 0.8671, 0.6808, and 0.6721 m2, respectively. The corresponding chevron angle are 33°, 64° (double chevron) and 61°, repectively. The calculated results show that the heat transfer efficient for NT10 is higher than that of GC26 by approximately 6.35% and is higher than SW26 by 10.3%. The results indicate that the heat transfer characteristics for the double chevron plate outperform that of the single chevron plate. On the other hand, the pressure drop is also increased with the double chevron as well as chevron angle. However, it is found that the double chevron design provides a better heat transfer capability subject to identical pressure drop.

Relationship Between Pressure Drop and Heat Transfer of Fully Developed Flow in Smooth Horizontal Circular Tubes and Spiral Coiled Tubes in the Laminar Flow Regime

2021 ◽  
Author(s):  
Rahul H Patil ◽  
Mandar V Tendolkar
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Laminar Flow ◽  
Flow Regime ◽  
Length Ratio ◽  
Dimensionless Group ◽  
Laminar Flow Regime ◽  
Friction Factors ◽  
Flow Through ◽  
Spiral Coils

Abstract Studies on isothermal steady state frictional pressure drop for flow of petroleum base oil SN70, SN150, Diesel and water are carried out in spiral coils with diameter to length ratio, 0.00042, 0.00047, 0.00073, 0.00164, 0.00189, 0.003 and 0.0037. An attempt is made to correlate friction factors with a better and more appropriate dimensionless group for flow of Newtonian fluids through spiral coiled tubes. An innovative approach of correlating heat transfer data with the newly established dimensionless group is presented. Heat transfer experiments are performed for spiral coils with diameter to length ratio 0.000474, 0.00042, 0.001896, 0.00198, 0.000942, 0.00164 in laminar flow regime. Suitable correlations for friction factors and Nusselt numbers are proposed. Relationship between pressure drop and heat transfer is studied. The incapability of the conventional analogy equations to estimate the heat and momentum transfer coefficients for laminar flow through straight or curved tubes is explained based on the viscous and form drag existing in straight and curved pipe flow. The limitations of the existing analogy equations are examined critically. A new general analogy equation is derived for laminar flow through spiral and straight tubes considering the influencing geometrical parameters of the tube. Keywords: Forced Convection; Heat and Mass transfer; Heat Exchangers; Thermal Systems.

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