scholarly journals Heat transfer enhancement and torque reduction by traveling wave-like blowing and suction in turbulent Taylor-Couette flow

2021 ◽  
Vol 16 (1) ◽  
pp. JTST0003-JTST0003
Author(s):  
Hiroya MAMORI ◽  
Koji FUKUDOME ◽  
Kohei OGINO ◽  
Naoya FUKUSHIMA ◽  
Makoto YAMAMOTO
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Couette Flow ◽  
Traveling Wave ◽  
Transfer Enhancement ◽  
Taylor Couette ◽  
Taylor Couette Flow

Molecular Dynamics Simulation on Micro Couette Flow of Nanofluids

2011 ◽  
Vol 284-286 ◽  
pp. 658-661
Author(s):  
Wen Zheng Cui ◽  
Min Li Bai ◽  
Ji Zu Lv ◽  
Xiao Jie Li
Keyword(s):  
Heat Transfer ◽  
Molecular Dynamics ◽  
Heat Transfer Enhancement ◽  
Couette Flow ◽  
Liquid Argon ◽  
Visual Observation ◽  
Solid Surfaces ◽  
Dynamics Simulation ◽  
Transfer Enhancement ◽  
Base Liquid

This research applied molecular dynamics method to micro Couette flow of nanofluids, in order to examine the absorption layer near solid surfaces, and propose mechanisms of heat transfer enhancement due to flow. The model of nanofluids consisted of 4 nm Cu nanoparticles and liquid argon as base liquid, Lennard-Jones potential function was adopted to deal with the interactions between atoms. Through visual observation and analysis, it was found that the even-distributed liquid argon atoms near solid surfaces could be seemed as a reform to base liquid and had contributed to heat transfer enhancement. In the process of Couette flow, nanoparticles were rotating and vibrating besides moving translationally. The micro-motions of nanoparticles could disturb the continuity of fluid and strengthen partial flow nearby nanoparticles, and enhance heat transfer in nanofluids.

Heat Transfer Enhancement in Axial Taylor-Couette Flow

2005 ◽  
Author(s):  
S. Gilchrist ◽  
C. Y. Ching ◽  
D. Ewing
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Couette Flow ◽  
Reynolds Numbers ◽  
Taylor Number ◽  
Number Range ◽  
Taylor Couette ◽  
Number Case ◽  
Taylor Couette Flow

An experimental investigation was performed to determine the effect that surface roughness has on the heat transfer in an axial Taylor-Couette flow. The experiments were performed using an inner rotating cylinder in a stationary water jacket for Taylor numbers of 106 to 5×107 and axial Reynolds numbers of 900 to 2100. Experiments were performed for a smooth inner cylinder, a cylinder with two-dimensional rib roughness and a cylinder with three-dimensional cubic protrusions. The heat transfer results for the smooth cylinder were in good agreement with existing experimental data. The change in the Nusselt number was relatively independent of the axial Reynolds number for the cylinder with rib roughness. This result was similar to the smooth wall case but the heat transfer was enhanced by 5% to 40% over the Taylor number range. The Nusselt number for the cylinder with cubic protrusions exhibited an axial Reynolds number dependence. For a low axial Reynolds number of 980, the Nusselt number increased with the Taylor number in a similar way to the other test cylinders. At higher axial Reynolds numbers, the heat transfer was initially independent of the Taylor number before increasing with Taylor number similar to the lower Reynolds number case. In this higher axial Reynolds number case the heat transfer was enhanced by up to 100% at the lowest Taylor number of 1×106 and by approximately 35% at the highest Taylor number of 5×107.

scholarly journals On the Microscopic Flow Characteristics of Nanofluids by Molecular Dynamics Simulation on Couette Flow

2012 ◽  
Vol 5 (1) ◽  
pp. 21-27 ◽  
Author(s):  
Wenzheng Cui ◽  
Minli Bai ◽  
Jizu Lv ◽  
Xiaojie Li
Keyword(s):  
Heat Transfer ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Heat Transfer Enhancement ◽  
Couette Flow ◽  
Flow Characteristics ◽  
Dynamics Simulation ◽  
Shear Direction ◽  
Transfer Enhancement ◽  
Microscopic Flow

Adding a small amount of nanoparticles to conventional fluids (nanofluids) has been proved to be an effective way for improving capability of heat transferring in base fluids. The change in micro structure of base fluids and micro motion of nanoparticles may be key factors for heat transfer enhancement of nanofluids. Therefore, it is essential to examine these mechanisms on microscopic level. The present work performed a Molecular Dynamics simulation on Couette flow of nanofluids and investigated the microscopic flow characteristics through visual observation and statistic analysis. It was found that the even-distributed liquid argon atoms near solid surfaces of nanoparticles could be seemed as a reform to base liquid and had contributed to heat transfer enhancement. In the process of Couette flow, nanoparticles moved quickly in the shear direction accompanying with motions of rotation and vibration in the other two directions. When the shearing velocity was increased, the motions of nanoparticles were strengthened significantly. The motions of nanoparticles could disturb the continuity of fluid and strengthen partial flowing around nanoparticles, and further enhanced heat transferring in nanofluids.

Heat Transfer in a Taylor-Couette Flow

2017 ◽  
Author(s):  
Vinicius Malatesta ◽  
Vinícius Hagemeyer Chiumento
Keyword(s):  
Heat Transfer ◽  
Couette Flow ◽  
Taylor Couette ◽  
Taylor Couette Flow

scholarly journals Numerical study of heat flow characteristics of turbulent Taylor-Couette flow in slit wall mode

2021 ◽  
Vol 9 ◽  
Author(s):  
Dong Liu ◽  
◽  
Mohammed Mohammedsalih ◽  
Amponsah-Gyenin Nana Kofi ◽  
Shi-cheng Ding ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Couette Flow ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Simulation Method ◽  
Industrial Applications ◽  
Small Scale ◽  
Taylor Couette ◽  
Taylor Couette Flow

Heat transfer enhancement is by far an important component in the design of numerous industrial applications of Taylor-Couette flow including electric motors and particularly rotating machinery. To optimize the performances of these machines, superior knowledge of the fluid flow is vital to better estimate the heat transfer distribution. This study will specifically consider the effect the slit number and width possess on the distribution of turbulent Taylor-Couette flow and the resulting heat transfer correlation in the annulus of two concentric cylinders under varying conditions. A numerical simulation method is intended for the study using varying slit structure parameters of widths (2.5 ≤ w ≤ 7.5) mm and fitted with 6, 9 and 12 number of slits. The slit effect is then investigated under both isotherm and non-isotherm conditions considering the interactions between fluid flow regions in the mainstream area and the annulus. The small-scale vortex that appears in the annulus region improves the heat transferability between the fluid in the annulus and the main region as well as the heat transfer performance of the model with a gradual increase in Reynolds number.

Numerical Simulations of Heat Transfer in Taylor-Couette Flow

1998 ◽  
Vol 120 (1) ◽  
pp. 65-71 ◽  
Author(s):  
R. Kedia ◽  
M. L. Hunt ◽  
T. Colonius
Keyword(s):  
Heat Transfer ◽  
Numerical Simulations ◽  
Couette Flow ◽  
Stokes Equations ◽  
Taylor Vortex ◽  
Cylinder Surface ◽  
Stable States ◽  
Grashof Number ◽  
Taylor Couette ◽  
Taylor Couette Flow

Numerical simulations have been performed to study the effects of the gravitational and the centrifugal potentials on the stability of heated, incompressible Taylor-Couette flow. The flow is confined between two differentially heated, concentric cylinders, and the inner cylinder is allowed to rotate. The Navier-Stokes equations and the coupled energy equation are solved using a spectral method. To validate the code, comparisons are made with existing linear stability analysis and with experiments. The code is used to calculate the local and average heat transfer coefficients for a fixed Reynolds number (Re = 100) and a range of Grashof numbers. The investigation is primarily restricted to radius ratios 0.5 and 0.7 for fluids with Prandtl number of about 0.7. The variation of the local coefficients of heat transfer on the cylinder surface is investigated, and maps showing different stable states of the flow are presented. Results are also presented in terms of the equivalent conductivity, and show that heat transfer decreases with Grashof number in axisymmetric Taylor vortex flow regime, and increases with Grashof number after the flow becomes nonaxisymmetric.

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