The Effect of Using Nanofluids on Triangular Microchannel Heat Exchanger Performance

2010 ◽  
Author(s):  
G. Bhaskaran ◽  
H. A. Mohammed ◽  
N. H. Shuaib
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Volume Fraction ◽  
Numerical Study ◽  
Particle Volume Fraction ◽  
Three Dimensional ◽  
Hydrodynamic Performance ◽  
Particle Volume ◽  
Microchannel Heat Exchanger

A numerical study is performed to study the effects of using various types of nanofluids on a triangular shaped microchannel heat exchanger (MCHE). The performance of an aluminum MCHE with various types of nanofluids such as Al2O3, CuO, SiO2, Ag and TiO2 and diamond particles with particle volume fraction of 2% using water as base fluid is comprehensively analyzed. The three-dimensional steady, laminar developing flow and conjugate heat transfer of a balanced MCHE were solved using finite volume method. In order to maintain laminar flow in the microchannels, Re number was ranged from 100 to 800. The other parameters tested in this study include the effects of Reynolds number towards the temperature, effectiveness and pressure drop of the MCHE. It is found that nanofluids have improved the temperature profile and heat transfer rate of the MCHE. The increase in pressure drop was minimal while the thermal and hydrodynamic performance of the heat exchanger was enhanced.

Numerical Study of Forced Convection of Nanofluids in a Microchannel Heat Sink

2008 ◽  
Author(s):  
Parisa Vaziee ◽  
Omid Abouali
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Sink ◽  
Volume Fraction ◽  
Numerical Study ◽  
Heat Removal ◽  
Al2o3 Nanoparticles ◽  
Microchannel Heat Sink ◽  
Particle Volume ◽  
Volume Fractions

Effectiveness of the microchannel heat sink cooled by nanofluids with various particle volume fractions is investigated numerically using the latest theoretical models for conductivity and viscosity of the nanofluids. Both laminar and turbulent flows are considered in this research. The model of conductivity used in this research accounts for the fundamental role of Brownian motion of the nanoparticles which is in good agreement with the experimental data. The changes in viscosity of the nanofluid due to temperature variation are considered also. Final results are compared with the experimental measurements for heat transfer coefficient and pressure drop in microchannel. Enhancement in heat transfer is achieved for laminar flow with increasing of volume fraction of Al2O3 nanoparticles. But for turbulent flow an enhancement of heat removal was not seen and using higher volume fractions of nanoparticles increases the maximum substrate temperature. Pressure drop is increased with using nanofluids because of the augmentation in the viscosity and this increase is more noticeable in higher Reynolds numbers.

Numerical Study of Thermofluid Characteristics of a Double Spirally Coiled Tube Heat Exchanger

2019 ◽  
Vol 11 (4) ◽  
Author(s):  
Mahmoud Abdelmagied
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Numerical Study ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Curvature Ratio ◽  
Coiled Tube ◽  
Tube Heat Exchanger ◽  
Enhancing Heat Transfer

In this study, the thermofluid characteristics of double spirally coiled tube heat exchanger (DSCTHE) were investigated numerically. A three-dimensional (3D) computational fluid dynamic (CFD) model was developed using ansys 14.5 software package. To investigate the heat transfer and pressure drop characteristics of DSCTHE, the Realize k–ε turbulence viscous model had been applied with enhanced wall treatment for simulating the turbulent thermofluid characteristics. The governing equations were solved by a finite volume discretization method. The effect of coil curvature ratio on DSCTHE was investigated with three various curvature ratios of 0.023–0.031 and 0.045 for inner tube side and 0.024–0.032–0.047 for annular side. The effects of addition of Al2O3 nanoparticle on water flows inside inner tube side or annular side with different volume concentrations of 0.5%, 1%, and 2% were also presented. The numerical results were carried out for Reynolds number with a range from 3500 to 21,500 for inner tube side and from 5000 to 24,000 for annular side, respectively. The obtained results showed that with increasing coil curvature ratio, a significant effect was discovered on enhancing heat transfer in DSCTHE at the expense of increasing pressure drop. The results also showed that the heat transfer enhancement was increased with increasing Al2O3 nanofluid concentration, and the penalty of pressure drop was approximately negligible.

Numerical Study of Flow and Heat Transfer of Heat Exchanger with Louver Baffles

2014 ◽  
Vol 721 ◽  
pp. 174-177 ◽  
Author(s):  
Hui Lai
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Energy Savings ◽  
Numerical Study ◽  
Dead Zone ◽  
Three Dimensional ◽  
Three Dimensional Model ◽  
Local Flow ◽  
Flow And Heat Transfer

This paper presents a heat exchanger of louver baffle, the establishment of a three-dimensional model, research by numerical simulation of flow and heat transfer performance of the heat exchanger baffles different louver angle, and analyzes its local temperature, and evaluated for its overall performance. The results show that louver baffle heat exchanger avoids the existence of traditional segmental baffle heat exchanger problem after baffle local flow dead zone; compared with conventional segmental baffle heat exchanger, louver baffle heat exchanger greatly reduces the heat exchanger shell side pressure drop; louver baffle heat exchanger in the unit pressure drop coefficients are higher than the segmental baffle heat exchanger, and with the baffle plate angle increases, with significant energy savings.

Heat transfer enhancement from inline and staggered arrays of cylinders in a heat exchanger using alumina-water nanofluid

2020 ◽  
pp. 1-31
Author(s):  
Mohd. Asif ◽  
Rashi Chaturvedi ◽  
Amit Dhiman
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Exchanger ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Nanoparticle Concentration ◽  
Transfer Enhancement ◽  
Particle Volume ◽  
Circular Tubes ◽  
Heat Transfer Augmentation

Abstract The flow of alumina-water nanofluid across heated circular tubes arranged in inline and staggered arrays in a heat exchanger has been studied. The thermophysical properties of the nanofluid are determined using Corcione correlations, which are based on several experiments. The nanoparticle diameter dp is between 10 and 50 nm, with particle volume fraction ϕ varying from 0.01 to 0.05 and Reynolds number Re ranging from 10 to 200. Heat transfer augmentation takes place when nanoparticle concentration is increased. Mean Nusselt number NuM is increased by 31% when ϕ is increased from 0.01 to 0.05 at Re = 200 and dp = 10 nm in an inline array and by 25% in a staggered array. The use of smaller nanoparticles significantly promotes the thermal performance of the heat exchange arrays; NuM is enhanced by 20% for the inline array and by 16% for the staggering array when dp decreases from 50 nm to 10 nm at Re = 200 and ϕ = 0.05. NuM of the staggering array of cylinders at Re = 200, dp = 10 nm and ϕ = 0.05 is 60% greater than NuM of an inline array of cylinders. Finally, correlations are derived for the calculation of NuM of inline as well as staggered arrays.

Numerical study of heat transfer and Hall current impact on peristaltic propulsion of particle-fluid suspension with compliant wall properties

2019 ◽  
Vol 33 (35) ◽  
pp. 1950439 ◽  
Author(s):  
M. M. Bhatti ◽  
Rahmat Ellahi ◽  
A. Zeeshan ◽  
M. Marin ◽  
N. Ijaz
Keyword(s):  
Heat Transfer ◽  
Volume Fraction ◽  
Hall Current ◽  
Numerical Study ◽  
Nonlinear Differential Equations ◽  
Particle Volume Fraction ◽  
Mathematical Formulation ◽  
Solid Particles ◽  
Particle Volume ◽  
The Impact

In this paper, the effects of heat transfer and Hall current on the sinusoidal motion of solid particles through a planar channel has been discussed. The walls of the channel are considered as compliant under the effects of magnetohydrodynamics. The mathematical formulation has been performed using energy equation, momentum equation, and Ohm’s law. The modeled equations are further modified by taking the assumption of a zero Reynolds number and long wavelength. Numerical shooting technique has been employed to solve the nonlinear differential equations. The impact of all the emerging parameters such as wall rigidity, wall tension, mass characterization, Hall parameter, Hartmann number, Weissenberg number, particle volume fraction, Prandtl number, and Eckert number, respectively. Particularly, we discussed their effects on velocity and temperature profile.

scholarly journals Numerical Study on Flow and Heat Transfer Characteristics of Trapezoidal Printed Circuit Heat Exchanger

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1589
Author(s):  
Yuxuan Ji ◽  
Kaixiang Xing ◽  
Kefa Cen ◽  
Mingjiang Ni ◽  
Haoran Xu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Numerical Study ◽  
Three Dimensional ◽  
Channel Structure ◽  
Complex Flow ◽  
Compact Structure ◽  
Printed Circuit ◽  
Flow And Heat Transfer

Printed circuit heat exchanger (PCHE) is a promising regenerative device in the sCO2 power cycle, with the advantages of a large specific surface area and compact structure. Its tiny and complex flow channel structure brings enhanced heat transfer performance, while increasing pressure drop losses. It is, thus, important to balance heat transfer and flow resistance performances with the consideration of sCO2 as the working agent. Herein, three-dimensional models are built with a full consideration of fluid flow and heat transfer fields. A trapezoidal channel is developed and its thermal–hydraulic performances are compared with the straight, the S-shape, and the zigzag structures. Nusselt numbers and the Fanning friction factors are analyzed with respect to the changes in Reynolds numbers and structure geometric parameters. A sandwiched structure that couples two hot channels with one cold channel is further designed to match the heat transfer capacity and the velocity of sCO2 flows between different sides. Through this novel design, we can reduce the pressure drop by 75% and increase the regenerative efficiency by 5%. This work can serve as a solid reference for the design and applications of PCHEs.

scholarly journals Numerical Simulation of Free Convection in a Partially Heated Three-Dimensional Enclosure Filled with Ionanofluid ([C4mim][NTf2]-Cu)

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Said Bouchta ◽  
M’barek Feddaoui ◽  
Abdellatif Dayf
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Free Convection ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Three Dimensional ◽  
Particle Volume ◽  
Simplec Algorithm ◽  
Current Lines ◽  
Volume Method

A numerical analysis was performed to study free convection in a stationary laminar regime in a partially heated cube filled with ionanofluid. To numerically solve the dimensionless equations, we applied the finite volume method using the SIMPLEC algorithm for pressure correction. All walls are adiabatic, except for the left and right side walls which are partially heated differently. At the end of this simulation, several results are given in the form of current lines, isotherms, and variations in the Nusselt number. These results are obtained by analyzing the effect of a set of factors such as Rayleigh number, particle volume fraction, cold and source position on the dynamic and thermal fields, and heat transfer. It has been shown that the percentage of nanoparticles and high Rayleigh numbers significantly increase heat transfer by ionanofluid. Two comparisons have been made, between ionic fluid and ionanofluid at isotherms and streamlines, and between nanofluid and ionanofluid at Nusselt number, which show the advantage of using ionanofluid in heat transfer.

scholarly journals An Experimental Study on Heat Transfer and Pressure Drop of CuO-Water Nanofluid

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Bayram Sahin ◽  
Eyuphan Manay ◽  
Eda Feyza Akyurek
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Transfer Enhancement ◽  
Heat Transfer Performance ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Horizontal Tube ◽  
Transfer Performance ◽  
Transfer Enhancement ◽  
Particle Volume

Heat transfer and pressure drop characteristics of water based CuO nanofluid inside a horizontal tube were investigated experimentally. The upper limitation of the particle volume fraction with respect to heat transfer performance was also found. CuO-water nanofluids with volume fractions of 0.5%, 1%, 2%, and 4% were prepared by dispersing the CuO nanoparticles with an average diameter of 33 nm into deionised water. Experiments were carried out under the steady-state, constant heat flux, and turbulent flow regime conditions. The variations of the average Nusselt number and the friction factor with the Reynolds number were presented. For all given particle volume concentrations, heat transfer enhancements were calculated. It was concluded that the particle volume concentrations higher than 1% vol. were not appropriate with respect to the heat transfer performance of the CuO-water nanofluid. No heat transfer enhancement was observed at Re = 4.000. The highest heat transfer enhancement was achieved at Re = 16.000 and ф = 0.005.

scholarly journals New patterns in high-speed granular flows

2015 ◽  
Vol 769 ◽  
pp. 218-228 ◽  
Author(s):  
Nicolas Brodu ◽  
Renaud Delannay ◽  
Alexandre Valance ◽  
Patrick Richard
Keyword(s):  
High Speed ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Scaling Law ◽  
Three Dimensional ◽  
Secondary Flows ◽  
Particle Volume ◽  
Rheological Models ◽  
Granular Gas ◽  
Internal Structures

We report on new patterns in high-speed flows of granular materials obtained by means of extensive numerical simulations. These patterns emerge from the destabilization of unidirectional flows upon increase of mass holdup and inclination angle, and are characterized by complex internal structures, including secondary flows, heterogeneous particle volume fraction, symmetry breaking and dynamically maintained order. In particular, we evidenced steady and fully developed ‘supported’ flows, which consist of a dense core surrounded by a highly energetic granular gas. Interestingly, despite their overall diversity, these regimes are shown to obey a scaling law for the mass flow rate as a function of the mass holdup. This unique set of three-dimensional flow regimes raises new challenges for extending the scope of current granular rheological models.

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