An Investigation of the Forced Convection and Heat Transfer with a Cylindrical Agitator Subjected to Non-Newtonian Nanofluids

2018 ◽  
Vol 73 (9) ◽  
pp. 869-882
Author(s):  
Botong Li ◽  
Liancun Zheng ◽  
Liangliang Zhu ◽  
Tao Liu ◽  
Wei Zhang
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Volume Fraction ◽  
Temperature Fields ◽  
Nanoparticle Volume Fraction ◽  
Newtonian Flow ◽  
Convection And Heat Transfer ◽  
Velocity And Temperature Fields ◽  
Laminar Forced Convection ◽  
The Impact

AbstractThe present research performed a numerical simulation of laminar forced convection nanofluid-based non-Newtonian flow in a channel connecting a tank with heating regions. To achieve a rapid diffusion of heat, a cylindrical agitator is inserted into the tank. Power-law modelling is employed to describe the effect of non-Newtonian behaviour. The velocity and temperature fields and heat transfer coefficient ratio are studied systematically, taking into account the impact of various parameters, such as the generalised Reynolds number Re, generalised Prandtl number Pr, angular velocity of a cylinderω, nanoparticle volume fractionϕ, mixer size and location. Our research reveals that, to improve the heat transfer in practice, several applicable strategies are available, including the addition of more nanoparticles into the base fluid, which proved to be the most efficient method to enhance the heat transfer of a nanofluid.

scholarly journals Numerical Study of Laminar Forced Convection of Water/Al2o3 Nanofluid in an Annulus with Constant Wall Temperature

2013 ◽  
Vol 14 (1) ◽  
Author(s):  
Amin Kashani ◽  
Davood Jalali-vahid ◽  
Siamak Hossainpour
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Volume Concentration ◽  
Volume Fraction ◽  
Numerical Study ◽  
Flow Behavior ◽  
Convective Heat Transfer Coefficient ◽  
Two Phase ◽  
Constant Wall Temperature ◽  
Laminar Forced Convection

Laminar forced convection of a nanofluid consisting of water and Al2O3 in a horizontal annulus has been studied numerically. Two-phase mixture model has been used to investigate thermal behaviors of the nanofluid over constant temperature thermal boundary condition and with different volume concentration of nanoparticles. Comparisons with previously published experimental and analytical works on flow behavior in horizontal annulus show good agreements between the results as volume fraction is zero. In general convective heat transfer coefficient increases with nanoparticle concentration. ABSTRAK: Kertaskerja ini mengkaji secara numerik olakan paksa bendalir lamina yang menganduangi air dan Al2O3 didalam anulus mendatar. Model campuran dua fasa digunakan bagi mengkaji tingkah laku haba bendalir nano pada keadaan suhu malar dengan kepekatan nanopartikel berbeza. Perbandingan dengan karya eksperimen dan analitikal yang telah diterbitkan menunjukkan bahawa kelakuan aliran didalm anulus mendatar adalah baik apabila pecahan isipadu adalah sifar. Pada amnya, pekali pemindahan haba olakan meningkat dengan kepekatan nanopartikel. KEYWORDS: nanofluid; volume concentration; heat transfer enhancement; laminar flow convection; annulus

Flow and heat transfer of couple stress nanofluid sandwiched between viscous fluids

2019 ◽  
Vol 29 (11) ◽  
pp. 4262-4276 ◽  
Author(s):  
C. Jawali Umavathi ◽  
Mikhail Sheremet
Keyword(s):  
Heat Transfer ◽  
Couple Stress ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Viscous Fluids ◽  
Temperature Fields ◽  
Content Type ◽  
Stress Parameter ◽  
Transfer Behavior ◽  
Velocity And Temperature Fields

Purpose The purpose of this study is a numerical analysis of steady-state heat transfer behavior of couple-stress nanofluid sandwiched between viscous fluids. It should be noted that this research deals with the development of a cooling system for the electronic devices. Design/methodology/approach Stokes model is used to define the couple-stress fluid and the single-phase nanofluid model is used to define the nanofluid transport processes. The fluids in all regions are assumed to be incompressible, immiscible and the transport properties in all the three layers are assumed to be constant. The governing coupled linear ordinary differential equations are made dimensionless by using appropriate fundamental quantities. The exact solutions obtained for the velocity and temperature fields are evaluated numerically for various model parameters. Findings The results are demonstrated using different types of nanoparticles such as copper, silver, silicon oxide (SiO2), titanium oxide (TiO2) and diamond. The investigations are carried out using copper–water nanofluid for different values of couple-stress parameter a with a range of 0 = a = 12, solid volume fraction ϕ with a range of 0.0 ≤ ϕ ≤ 0.05, Eckert number Ec with a range of 0.001 ≤ Ec ≤ 6 and Prandtl number Pr with a range of 0.001 ≤ Pr ≤ 6. It was found that the Nusselt number increases by increasing the couple stress parameter, Eckert number and Prandtl number and it decreases with a growth of the solid volume fraction parameter. It was also observed that using SiO2–water nanofluid, the optimal Nusselt number is obtained. Further, using copper, silver, diamond and TiO2, nanoparticles and water as a base fluid does not show any significant changes in the rate of heat transfer. The couple-stress parameter enhances the velocity and temperature fields whereas the solid volume fraction suppresses the flow field for both Newtonian and couple-stress fluid. Originality/value The originality of this work is to analyze the heat transfer behavior of couple-stress nanofluid sandwiched between viscous fluids. The results would benefit scientists and engineers to become familiar with the analysis of convective heat transfer and flow structures in nanofluids and the way to predict the heat transfer rate in advanced technical systems, in industrial sectors including transportation, power generation, chemical sectors, electronics, etc.

Forced Convection Heat Transfer from Nonisothermal Thin Needles

1978 ◽  
Vol 100 (2) ◽  
pp. 358-362 ◽  
Author(s):  
J. L. S. Chen ◽  
T. N. Smith
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Incompressible Flows ◽  
Convection Heat Transfer ◽  
Temperature Fields ◽  
Convection Heat ◽  
Needle Size ◽  
Forced Convection Heat Transfer ◽  
Laminar Forced Convection ◽  
Accelerating Flow

The steady laminar forced convection heat transfer from nonisothermal thin needles in nonuniform incompressible flows is investigated analytically. Similarity temperature fields and heat transfer characteristics for needles with power-law thermal variations in (1) wall temperature, and (2) surface heat flux, are obtained. The influence of needle size and Prandtl number on the thermal behavior of the flow is examined for a uniform as well as an accelerating flow.

Laminar Forced Convection of a Dissipative Fluid in a Channel

1966 ◽  
Vol 88 (2) ◽  
pp. 161-167 ◽  
Author(s):  
V. P. Tyagi
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Viscous Dissipation ◽  
Graphical Representation ◽  
Temperature Fields ◽  
Source Distribution ◽  
Mathematical Treatment ◽  
Constant Property ◽  
Cross Sectional ◽  
Laminar Forced Convection

In the present study, the steady laminar forced convection problem of heat transfer in the fully developed constant property flow of liquids through a certain class of channels is analyzed by considering the contribution of heat due to viscosity. The effects of viscous dissipation on the heat transfer are emphasized. A class of sufficiently long straight channels with uniform cross-sectional area is chosen such that the solutions for velocity and temperature fields are deducible directly from the equations of the boundary curves. The wall temperature is allowed to vary linearly in the axial direction, and some heat-source distribution, other than that due to viscosity, is imagined to be present in the flow field. The general solution of the problem for the given class of channels is given directly by avoiding the details of the mathematical treatment of the governing equations. To illustrate the general mathematical derivations and to visualize the effects of viscous dissipation, some basic examples have been investigated and the graphical representation of several relevant results is given in a number of figures. In the last section of this study, various relevant results and figures have been discussed from the point of view of viscous dissipation phenomena.

Simulations of Forced Convection Heat Transfer of Nanofluids in Parallel-Plate Microchannels Using Dissipative Particle Dynamics

2012 ◽  
Author(s):  
Toru Yamada ◽  
Yutaka Asako ◽  
Chungpyo Hong ◽  
Mohammad Faghri
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Forced Convection ◽  
Parallel Plate ◽  
Volume Fraction ◽  
Dissipative Particle Dynamics ◽  
Convection Heat Transfer ◽  
Particle Dynamics ◽  
Nanoparticle Volume Fraction ◽  
Convection Heat

The effect of nanoparticle volume fraction on hydrodynamic and thermally fully developed forced convection heat transfer in parallel-plate channels was numerically studied under constant wall temperature boundary condition using energy conserving dissipative particle dynamics (DPDe). The solution domain was considered to be two-dimensional with periodic boundary condition in the flow direction and no-slip boundary conditions at top and bottom walls of the channel. The results were shown via fully developed velocity and temperature distributions across the channel cross-section. Nusselt numbers are calculated from the gradient of temperature at the wall and compared with the analytical solutions. The effect of nanoparticle volume fraction on Nusselt number was discussed.

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