Mixed convection in a vertical circular microchannel

Авраменко, А. А.; Tyrinov, A. I.; Shevchuk, Igor V.; Dmitrenko, N.P.; Kravchuk, Alexander V.; Shevchuk, V.I.

doi:10.1016/j.ijthermalsci.2017.07.001

Cited by 34 publications

(15 citation statements)

References 30 publications

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“…1), whereas potential flow outside of the boundary layer is subject to a hyperbolic law [22] where U ∞ is the velocity of the main flow and u 1 is a constant. In accordance with the work [18], self-similar variables for this case are…”

Section: Fluid Flowmentioning

confidence: 66%

“…The given above analysis of the research activities on fluid flow and heat transfer in microchannels performed over the past few years indicates that studies incorporated different geometries of microchannels, namely circular, flat, rectangular, and triangular, and straight and curved, subject to different boundary and initial conditions. In the works [15][16][17][18], the lattice Boltzmann method (LBM) was successfully applied to simulate stationary and accelerated microflows in straight and curved microchannels. The simulations enabled quantifying the effects of the Rayleigh, Prandtl, and Nusselt numbers, as well as slippage on the flow development in circular, flat, and curved microchannels.…”

Section: Introductionmentioning

confidence: 99%

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Heat transfer and hydrodynamics of slip confusor flow under second-order boundary conditions

Авраменко

Dmitrenko

Shevchuk

2020

J Therm Anal Calorim

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The paper focused on an analytical analysis of the main features of heat transfer in incompressible steady-state flow in a microconfusor with account for the second-order slip boundary conditions. The second-order boundary conditions serve as a closure of a system of the continuity, transport, and energy differential equations. As a result, novel solutions were obtained for the velocity and temperature profiles, as well as for the friction coefficient and the Nusselt number. These solutions demonstrated that an increase in the Knudsen number leads to a decrease in the Nusselt number. It was shown that the account for the second-order terms in the boundary conditions noticeably affects the fluid flow characteristics and does not influence on the heat transfer characteristics. It was also revealed that flow slippage effects on heat transfer weaken with an increase in the Prandtl number.

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Section: Fluid Flowmentioning

confidence: 66%

Section: Introductionmentioning

confidence: 99%

Heat transfer and hydrodynamics of slip confusor flow under second-order boundary conditions

Авраменко

Dmitrenko

Shevchuk

2020

J Therm Anal Calorim

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“…Avramenko et al [27] numerically investigated the impact of mixed convection in a vertical microchannel with a circular cross-section. They found that the shape of the cross-section has a significant effect on the Nu ave .…”

Section: Introductionmentioning

confidence: 99%

“…From the studies reviewed on microchannels [22][23][24][25][26][27][28][29][30][31][32][33], it can be concluded that the use of microchannels, due to the increasing need of different industries for small and efficient heat exchangers, is considered to be more than before. Therefore, the behavior of microchannels in different environments needs to be given more attention.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Nanoparticle Shape and Microchannel Geometry on Fluid Flow and Heat Transfer in a Porous Microchannel

2020

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Microchannels are widely used in electrical and medical industries to improve the heat transfer of the cooling devices. In this paper, the fluid flow and heat transfer of water–Al2O3 nanofluids (NF) were numerically investigated considering the nanoparticle shape and different cross-sections of a porous microchannel. Spherical, cubic, and cylindrical shapes of the nanoparticle as well as circular, square, and triangular cross-sections of the microchannel were considered in the simulation. The finite volume method and the SIMPLE algorithm have been employed to solve the conservation equations numerically, and the k-ε turbulence model has been used to simulate the turbulence fluid flow. The models were simulated at Reynolds number ranging from 3000 to 9000, the nanoparticle volume fraction ranging from 1 to 3, and a porosity coefficient of 0.7. The results indicate that the average Nusselt number (Nuave) increases and the friction coefficient decreases with an increment in the Re for all cases. In addition, the rate of heat transfer in microchannels with triangular and circular cross-sections is reduced with growing Re values and concentration. The spherical nanoparticle leads to maximum heat transfer in the circular and triangular cross-sections. The heat transfer growth for these two cases are about 102.5% and 162.7%, respectively, which were obtained at a Reynolds number and concentration of 9000 and 3%, respectively. However, in the square cross-section, the maximum heat transfer increment was obtained using cylindrical nanoparticles, and it is equal to 80.2%.

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“…Kou et al [10] studied the effects of wall slip and temperature jump on heat and mass transfer characteristics of evaporative films. A.A. Avramenko et al [11] investigated mixed convection in a circular microchannel with the slip boundary conditions. As micro/nanotechnology develops, the size of micro/nanodevices are getting smaller and smaller.…”

Section: Introductionmentioning

confidence: 99%

Effects of Second-Order Velocity Slip and the Different Spherical Nanoparticles on Nanofluid Flow

2020

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The paper theoretically investigates the heat transfer of nanofluids with different nanoparticles inside a parallel-plate channel. Second-order slip condition is adopted due to the microscopic roughness in the microchannels. After proper transformation, nonlinear partial differential systems are converted to ordinary differential equations with unknown constants, and then solved by homotopy analysis method. The residual plot is drawn to verify the convergence of the solution. The semi-analytical expressions between NuB and NBT are acquired. The results show that both first-order slip parameter and second-order slip parameter have positive effects on NuB of the MHD flow. The effect of second-order velocity slip on NuB is obvious, and NuB in the alumina–water nanofluid is higher than that in the titania–water nanofluid. The positive correlation between slip parameters and Ndp is significant for the titania–water nanofluid.

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Mixed convection in a vertical circular microchannel

Cited by 34 publications

References 30 publications

Heat transfer and hydrodynamics of slip confusor flow under second-order boundary conditions

Heat transfer and hydrodynamics of slip confusor flow under second-order boundary conditions

The Effect of Nanoparticle Shape and Microchannel Geometry on Fluid Flow and Heat Transfer in a Porous Microchannel

Effects of Second-Order Velocity Slip and the Different Spherical Nanoparticles on Nanofluid Flow

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