Effect of magnetic field and nanoparticle shape on jet impingement over stationary and vibrating plates

2019 ◽  
Vol 29 (12) ◽  
pp. 4948-4970 ◽  
Author(s):  
Rajesh Nimmagadda ◽  
Godson Asirvatham Lazarus ◽  
Somchai Wongwises
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Heat Transfer Performance ◽  
Jet Impingement ◽  
Transfer Model ◽  
Transfer Performance ◽  
Content Type ◽  
Nanoparticle Shape ◽  
Vibrating Plates ◽  
Vibrating Plate

Purpose The purpose of this study is to numerically investigate the effect of jet impingement, magnetic field and nanoparticle shape (sphericity) on the hydrodynamic/heat transfer characteristics of nanofluids over stationary and vibrating plates. Design/methodology/approach A two-dimensional finite volume method-based homogeneous heat transfer model has been developed, validated and used in the present investigation. Three different shapes of non-spherical carbon nanoparticles namely nanotubes, nanorods and nanosheets are used in the analysis. Sphericity-based effective thermal conductivity of nanofluids with Brownian motion of nanoparticles is considered in the investigation. Moreover, the ranges of various comprehensive parameters used in the study are Re = 500 to 900, St = 0.0694 to 0.2083 and Ha = 0 to 80. Findings The hydrodynamic/heat transfer performance of jet impingement in the case of vibrating plate is 298 per cent higher than that of stationary plate at Re = 500. However, for the case of vibrating plate, a reduction in the heat transfer performance of 23.35 per cent is observed by increasing the jet Reynolds number from 500 to 900. In the case of vibrating plate, the saturation point for Strouhal number is found to be 0.0833 at Re = 900 and Ha = 0. Further decrement in St beyond this limit leads to a drastic reduction in the performance. Moreover, no recirculation in the flow is observed near the stagnation point for jet impingement over vibrating plate. It is also observed that the effect of magnetic field enhances the performance of jet impingement over a stationary plate by 36.18 per cent at Ha = 80 and Re = 900. Whereas, opposite trend is observed for the case of vibrating plate. Furthermore, at Re = 500, the percentage enhancement in the Nuavg values of 3 Vol.% carbon nanofluid with nanosheets, nanorods and nanotubes are found to be 47.53, 26.86 and 26.85 per cent when compared with the value obtained for pure water. Practical implications The present results will be useful in choosing nanosheets-based nanofluid as the efficient heat transfer medium in cooling of high power electronic devices. Moreover, the obtained saturation point in the Strouhal number of the vibrating plate will help in cooling of turbine blades, as well as paper and textile drying. Moreover, the developed homogeneous heat transfer model can also be used to study different micro-convection phenomena in nanofluids by considering them as source terms in the momentum equation. Originality/value Impingement of jet over two different plate types such as stationary and vibrating is completely analyzed with the use of a validated in-house FVM code. A complete investigation on the influence of external magnetic field on the performance of plate type configuration is evaluated. The three fundamental shapes of carbon nanoparticles are also evaluated to obtain sphericity based hydrodynamic/heat transfer performance of jet impingement.

Heat transfer hybrid nanofluid (1-Butanol/MoS2–Fe3O4) through a wavy porous cavity and its optimization

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Kh. Hosseinzadeh ◽  
Elham Montazer ◽  
Mohammad Behshad Shafii ◽  
D.D. Ganji
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Shape Factor ◽  
Average Nusselt Number ◽  
Heat Transfer Performance ◽  
Taguchi Methods ◽  
Hybrid Nanofluid ◽  
Transfer Performance ◽  
Content Type ◽  
Nanoparticle Shape

Purpose The purpose of this paper is to investigate natural convection in a porous wavy-walled enclosure that is including a cylinder cavity in the middle of it and filled with a hybrid nanofluid contains 1-Butanol as the base fluid and MoS2–Fe3O4 hybrid nanoparticles. Design/methodology/approach The domain of interest is bounded by constant temperature horizontal corrugated surfaces and isothermal vertical flat surfaces. The numerical outputs are explained in the type of isotherms, streamline and average Nusselt number with variations of the Rayleigh number, Hartmann number, nanoparticle shape factor and porosity of the porous medium. For solving the governing equations, the finite element method has been used. Findings The results show that Nuave is proportional to Rayleigh and nanoparticle shape factor directly as well as it has an inverse relation with Hartmann and porosity. The obtained results reveal that the shape factor parameter has a significant effect on the heat transfer performance, which shows a 55.44% contribution on the average Nusselt number. Originality/value As a novelty, to maximize the heat transfer performance in a corrugated walls enclosure, the optimal parameters have intended by using the response surface and Taguchi methods. Additionally, an accurate correlation for the average Nusselt number is developed with sensibly great precision.

scholarly journals Conjugate heat transfer performance of stepped lid-driven cavity with Al2O3/water nanofluid under forced and mixed convection

2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Naveen Janjanam ◽  
Rajesh Nimmagadda ◽  
Lazarus Godson Asirvatham ◽  
R. Harish ◽  
Somchai Wongwises
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Mixed Convection ◽  
Conjugate Heat Transfer ◽  
Heat Transfer Performance ◽  
Pure Water ◽  
Interface Temperature ◽  
Transfer Model ◽  
Transfer Performance ◽  
Driven Cavity

AbstractTwo-dimensional conjugate heat transfer performance of stepped lid-driven cavity was numerically investigated in the present study under forced and mixed convection in laminar regime. Pure water and Aluminium oxide (Al2O3)/water nanofluid with three different nanoparticle volume concentrations were considered. All the numerical simulations were performed in ANSYS FLUENT using homogeneous heat transfer model for Reynolds number, Re = 100 to 500 and Grashof number, Gr = 5000, 13,000 and 20,000. Effective thermal conductivity of the Al2O3/water nanofluid was evaluated by considering the Brownian motion of nanoparticles which results in 20.56% higher value for 3 vol.% Al2O3/water nanofluid in comparison with the lowest thermal conductivity value obtained in the present study. A solid region made up of silicon is present underneath the fluid region of the cavity in three geometrical configurations (forward step, backward step and no step) which results in conjugate heat transfer. For higher Re values (Re = 500), no much difference in the average Nusselt number (Nuavg) is observed between forced and mixed convection. Whereas, for Re = 100 and Gr = 20,000, Nuavg value of mixed convection is 24% higher than that of forced convection. Out of all the three configurations, at Re = 100, forward step with mixed convection results in higher heat transfer performance as the obtained interface temperature is lower than all other cases. Moreover, at Re = 500, 3 vol.% Al2O3/water nanofluid enhances the heat transfer performance by 23.63% in comparison with pure water for mixed convection with Gr = 20,000 in forward step.

scholarly journals Enhanced heat transfer characteristics of conjugated air jet impingement on a finned heat sink

2017 ◽  
Vol 21 (1 Part A) ◽  
pp. 279-288 ◽  
Author(s):  
Shuxia Qiu ◽  
Peng Xu ◽  
Liping Geng ◽  
Arun Mujumdar ◽  
Zhouting Jiang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Heat Sink ◽  
Heat Transfer Performance ◽  
Cooling System ◽  
Flow Characteristics ◽  
Jet Impingement ◽  
Transfer Performance ◽  
Transfer Enhancement ◽  
Air Jet

Air jet impingement is one of the effective cooling techniques employed in micro-electronic industry. To enhance the heat transfer performance, a cooling system with air jet impingement on a finned heat sink is evaluated via the computational fluid dynamics method. A two-dimensional confined slot air impinging on a finned flat plate is modeled. The numerical model is validated by comparison of the computed Nusselt number distribution on the impingement target with published experimental results. The flow characteristics and heat transfer performance of jet impingement on both of smooth and finned heat sinks are compared. It is observed that jet impingement over finned target plate improves the cooling performance significantly. A dimensionless heat transfer enhancement factor is introduced to quantify the effect of jet flow Reynolds number on the finned surface. The effect of rectangular fin dimensions on impingement heat transfer rate is discussed in order to optimize the cooling system. Also, the computed flow and thermal fields of the air impingement system are examined to explore the physical mechanisms for heat transfer enhancement.

Effect of Magnetic Field on the Laminar Heat Transfer Performance of Hybrid Nanofluid in a Lid Driven Cavity Over Solid Block

2020 ◽  
Author(s):  
Rajesh Nimmagadda ◽  
Durga Prakash Matta ◽  
Rony Reuven ◽  
Lazarus Godson Asirvatham ◽  
Somchai Wongwises ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Uniform Magnetic Field ◽  
Conjugate Heat Transfer ◽  
Heat Transfer Performance ◽  
Hybrid Nanofluid ◽  
Transfer Performance ◽  
Driven Cavity ◽  
The Magnetic Field ◽  
Solid Block

Abstract A 2D numerical investigation has been carried out to obtain the heat transfer performance of hybrid (Al2O3 + Ag) nanofluid in a lid driven cavity over solid block under the influence of uniform as well as non-uniform magnetic field. The geometrical domain consists of a cavity containing nanofluid that is driven by means of lid moving in one direction. This circulating nanofluid will extract enormous amount of heat from the solid block underneath the cavity resulting in conjugate heat transfer. A homogenous solver based on the finite volume method with conjugate heat transfer was developed and adopted in the existing study. The heat efficient hybrid nanofluid (HyNF) pair (2.4 vol.% Ag + 0.6 vol.% Al2O3) obtained by Nimmagadda and Venkatasubbaiah [1] is used in the present investigation. Moreover, efficient non-uniform sinusoidal magnetic field identified by Nimmagadda et al. [2] is also implemented and compared with uniform magnetic field. Furthermore, the magnetic field is applied over the geometrical domain along the two axial directions separately and the effective heat transfer performance is obtained. The significant impact of extensive parameters like Reynolds number, nanoparticle type, nanoparticle concentration, magnetic field type, magnetic field location and the strength of the magnetic field on heat transfer performance are systematically analyzed and presented.

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