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.

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.

EXPERIMENTAL STUDY ON THERMAL TRANSPORT PHENOMENON OF NANOFLUIDS AS WORKING FLUID IN HEAT EXCHANGER

2014 ◽  
Vol 22 (01) ◽  
pp. 1450005 ◽  
Author(s):  
SHUICHI TORII
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Transfer Performance ◽  
Pure Water ◽  
Horizontal Tube ◽  
Constant Heat Flux ◽  
Working Fluid ◽  
Transfer Performance ◽  
Nanoparticles Concentration ◽  
Transfer Behavior

This paper aims to study the convective heat transfer behavior of aqueous suspensions of nanoparticles flowing through a horizontal tube heated under constant heat flux condition. Consideration is given to the effects of particle concentration and Reynolds number on heat transfer enhancement and the possibility of nanofluids as the working fluid in various heat exchangers. It is found that (i) significant enhancement of heat transfer performance due to suspension of nanoparticles in the circular tube flow is observed in comparison with pure water as the working fluid, (ii) enhancement is intensified with an increase in the Reynolds number and the nanoparticles concentration, and (iii) substantial amplification of heat transfer performance is not attributed purely to the enhancement of thermal conductivity due to suspension of nanoparticles.

Comparative Study of Cooling Performance of Automobile Radiator Using Al2O3-Water and Carbon Nanotube-Water Nanofluid

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Sandesh S. Chougule ◽  
S. K. Sahu
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Base Fluid ◽  
Heat Transfer Performance ◽  
Pure Water ◽  
Transfer Performance ◽  
Nanoparticle Concentration ◽  
Cooling Performance ◽  
Forced Convective Heat Transfer ◽  
Better Than

In the present study, the forced convective heat transfer performance of two different nanofluids, namely, Al2O3-water and CNT-water has been studied experimentally in an automobile radiator. Four different concentrations of nanofluid in the range of 0.15–1 vol. % were prepared by the additions nanoparticles into the water as base fluid. The coolant flow rate is varied in the range of 2 l/min–5 l/min. Nanocoolants exhibit enormous change in the heat transfer compared with the pure water. The heat transfer performance of CNT-water nanofluid was found to be better than Al2O3-water nanocoolant. Furthermore, the Nusselt number is found to increase with the increase in the nanoparticle concentration and nanofluid velocity.

scholarly journals Augmentation of the Heat Transfer Performance of a Sinusoidal Corrugated Enclosure by Employing Hybrid Nanofluid

2014 ◽  
Vol 6 ◽  
pp. 147059 ◽  
Author(s):  
Behrouz Takabi ◽  
Saeed Salehi
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Performance ◽  
Heated Surface ◽  
Pure Water ◽  
Maximum Error ◽  
Temperature Fields ◽  
Working Fluid ◽  
Hybrid Nanofluid ◽  
Transfer Performance ◽  
Lower Temperature

This paper numerically examines laminar natural convection in a sinusoidal corrugated enclosure with a discrete heat source on the bottom wall, filled by pure water, Al2O3/water nanofluid, and Al2O3-Cu/water hybrid nanofluid which is a new advanced nanofluid with two kinds of nanoparticle materials. The effects of Rayleigh number (103≤Ra≤106) and water, nanofluid, and hybrid nanofluid (in volume concentration of 0% ≤ ϕ ≤ 2%) as the working fluid on temperature fields and heat transfer performance of the enclosure are investigated. The finite volume discretization method is employed to solve the set of governing equations. The results indicate that for all Rayleigh numbers been studied, employing hybrid nanofluid improves the heat transfer rate compared to nanofluid and water, which results in a better cooling performance of the enclosure and lower temperature of the heated surface. The rate of this enhancement is considerably more at higher values of Ra and volume concentrations. Furthermore, by applying the modeling results, two correlations are developed to estimate the average Nusselt number. The results reveal that the modeling data are in very good agreement with the predicted data. The maximum error for nanofluid and hybrid nanofluid was around 11% and 12%, respectively.

An Evaluation of the Application of Nanofluids in Intercooled Cycle Marine Gas Turbine Intercooler

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Ningbo Zhao ◽  
Xueyou Wen ◽  
Shuying Li
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Gas Turbine ◽  
Heat Transfer Performance ◽  
Volume Concentration ◽  
Inlet Temperature ◽  
Transfer Performance ◽  
Pumping Power ◽  
Flow And Heat Transfer ◽  
Overall Performance

Coolant is one of the important factors affecting the overall performance of the intercooler for the intercooled (IC) cycle marine gas turbine. Conventional coolants, such as water and ethylene glycol, have lower thermal conductivity which can hinder the development of highly effective compact intercooler. Nanofluids that consist of nanoparticles and base fluids have superior properties like extensively higher thermal conductivity and heat transfer performance compared to those of base fluids. This paper focuses on the application of two different water-based nanofluids containing aluminum oxide (Al2O3) and copper (Cu) nanoparticles in IC cycle marine gas turbine intercooler. The effectiveness-number of transfer unit method is used to evaluate the flow and heat transfer performance of intercooler, and the thermophysical properties of nanofluids are obtained from literature. Then, the effects of some important parameters, such as nanoparticle volume concentration, coolant Reynolds number, coolant inlet temperature, and gas side operating parameters on the flow and heat transfer performance of intercooler, are discussed in detail. The results demonstrate that nanofluids have excellent heat transfer performance and need lower pumping power in comparison with base fluids under different gas turbine operating conditions. Under the same heat transfer, Cu–water nanofluids can reduce more pumping power than Al2O3–water nanofluids. It is also concluded that the overall performance of intercooler can be enhanced when increasing the nanoparticle volume concentration and coolant Reynolds number and decreasing the coolant inlet temperature.

Increasing heat transfer performance of thermoplastic polyurethane by constructing thermal conduction channels of ultra-thin boron nitride nanosheets and carbon nanotubes

2020 ◽  
Vol 44 (43) ◽  
pp. 18823-18830
Author(s):  
Yue Ruan ◽  
Nian Li ◽  
Cui Liu ◽  
Liqing Chen ◽  
Shudong Zhang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Tensile Strength ◽  
Thermal Conduction ◽  
Heat Transfer Performance ◽  
Thermoplastic Polyurethane ◽  
Transfer Performance ◽  
Boron Nitride Nanosheets ◽  
Thermally Conductive

The TPU-based thermally conductive composite reaches a thermal conductivity of 1.35 W m−1 K−1 and increases the tensile strength by at least 300%.

Experimental and Numerical Studies of Fluid Flow Confined in Microchannel

2016 ◽  
Author(s):  
Yan Wang ◽  
Xiang Ling
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Reynolds Number ◽  
Fluid Flow ◽  
Friction Factor ◽  
Heat Transfer Performance ◽  
Pure Water ◽  
High Heat Flux ◽  
Transfer Performance ◽  
Parallel Microchannels

The heat transfer performance of fluid flowing in a microchannel was experimentally studied, to meet the requirement of extremely high heat flux removal of microelectronic devices. There were 10 parallel microchannels with rectangular cross-section in the stainless steel plate, which was covered by a glass plate to observe the fluid flowing behavior, and another heating plate made of aluminum alloy was positioned behind the microchannel. Single phase heat transfer and fluid flow downstream the microchannel experiments were conducted with both deionized water and ethanol. Besides experiments, numerical models were also set up to make a comparison with experimental results. It is found that the pressure drop increases rapidly with enlarging Reynolds number (200), especially for ethanol. With comparison, the flow resistance of pure water is smaller than ethanol. Results also show that the friction factor decreases with Reynolds number smaller than the critical value, while increases the velocity, the friction factor would like to keep little changed. We also find that the water friction factors obtained by CFD simulations in parallel microchannels are much larger than experiment results. With heat flux added to the fluid, the heat transfer performance can be enhanced with larger Re number and the temperature rise could be weaken. Compared against ethanol, water performed much better for heat removal. However, with intensive heat flux, both water and ethanol couldn’t meet the requirement and the temperature at outlet would increase remarkably, extremely for ethanol. These findings would be helpful for thermal management design and optimization.

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