Numerical Study of Heat Transfer Augmentation of Viscous Flow in Corrugated Channels

2000 ◽  
Vol 21 (5) ◽  
pp. 35-46 ◽  
Author(s):  
Nesreen Ghaddar, Ahmad El-Hajj
Keyword(s):  
Heat Transfer ◽  
Viscous Flow ◽  
Numerical Study ◽  
Heat Transfer Augmentation

A Numerical Study of Turbulent Boundary Layer Flow Over a Flat Surface With a Single Dimple

2000 ◽  
Author(s):  
Mark E. Kithcart ◽  
David E. Klett
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Boundary Layer Flow ◽  
Flat Surface ◽  
Numerical Study ◽  
Heat Transfer Augmentation ◽  
Study Results ◽  
Turbulent Boundary Layer Flow ◽  
Layer Flow

Abstract Turbulent boundary layer flow over a flat surface with a single dimple has been investigated numerically using the FLUENT CFD software package, and compared to an experiment by Ezerskii and Shekhov [1989], which studied the same configuration. The impetus for this work developed as a result of previous studies. Kithcart and Klett [1996], and Afanas’yev and Chudnovskiy [1992], showed that dimpled surfaces enhance heat transfer comparably to surfaces with protrusion roughness elements, but with a much lower drag penalty. However, the actual physical mechanisms involved in this phenomena were only partially known prior this study. Results obtained numerically are in good agreement with the experiment, most notably the confirmation of the existence of a region of enhanced heat transfer created by interaction of the flow with the dimple. In particular, the simulation indicates that heat transfer augmentation is a consequence of the development of a stagnation flow region within the dimple geometry, and the existence of coherent vortical structures which create a periodic flow-field within and immediately downstream of the dimple. This periodicity appears to govern the magnitude of the heat transfer augmentation.

Numerical Study on Heat Transfer Characteristics From Parallel Plates With Cavities Swept by a Visco-Elastic Fluid

2010 ◽  
Author(s):  
Hiroshi Suzuki ◽  
Shinpei Maeda ◽  
Yoshiyuki Komoda
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Thermal Field ◽  
Numerical Study ◽  
Geometric Parameters ◽  
Two Dimensional ◽  
Parallel Plates ◽  
Heat Transfer Characteristics ◽  
Elastic Fluid ◽  
Heat Transfer Augmentation

Two-dimensional numerical computations have been performed in order to investigate the development characteristics of flow and thermal field in a flow between parallel plates swept by a visco-elastic fluid. In the present study, the effect of the cavity number in the domain and of Reynolds number was focused on when the geometric parameters were set constant. From the results, it is found that the flow penetration into the cavities effectively causes the heat transfer augmentation in the cavities in any cavity region compared with that of water case. It is also found that the development of thermal field in cases of the present visco-elastic fluid is quicker compared with that of water cases. The present heat transfer augmentation technique using Barus effect of a visco-elastic fluid is effective in the range of low Reynolds number.

scholarly journals Nanofluid flow comprising gyrotactic microbes through a porous medium - a numerical study

2020 ◽  
pp. 332-332 ◽  
Author(s):  
Sohail Ahmad ◽  
Muhammad Ashraf ◽  
Kashif Ali
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Microbial Fuel Cells ◽  
Numerical Study ◽  
Parameter Method ◽  
Concentration Difference ◽  
Heat Transfer Augmentation ◽  
Graphical Comparison ◽  
Enzyme Biosensor ◽  
Successive Over Relaxation

Researchers have significantly contributed to heat transfer field and always made out much effort to find new solutions of heat transfer augmentation. In the concerned work, we have presented a novel study regarding heat and mass transfer flow of nanofluid in the presence of gyrotactic microbes through a porous medium past a stretching sheet. The nonlinear coupled ODEs are obtained after applying the persuasive tool of similarity transformation on governing model PDEs and then tackled numerically by exploiting the SOR (Successive over Relaxation) parameter method. The outcomes of assorted parameters for the flow are surveyed and discussed through graphs and tables. A graphical comparison is correlated with previously accomplished study and examined to be in an exceptional agreement. The culminations designate that the bioconvection Peclet number and microorganism concentration difference parameter enhance density of the motile microorganisms. Moreover, porosity parameter substantially increases shear stress on sheet surface. The addition of nanoparticles in microorganisms is beneficial to improvise the thermal efficiency of many systems like bacteria powered micro-mixers, microfluidics devices like micro-volumes and enzyme biosensor, microbial fuel cells and bio-microsystems like chip-shaped microdevices.

Numerical study of heat transfer and friction drag in MHD viscous flow of a nanofluid subject to the curved surface

2021 ◽  
pp. 1-16
Author(s):  
Wen-Hua Huang ◽  
Awatef Abidi ◽  
M. Riaz Khan ◽  
Dengwei Jing ◽  
Emad E. Mahmoud ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Viscous Flow ◽  
Numerical Study ◽  
Curved Surface ◽  
Friction Drag

An Experimental and Numerical Investigation of the Effect of Combustor-Nozzle Platform Misalignment on Endwall Heat Transfer at Transonic High Turbulence Conditions

2016 ◽  
Author(s):  
A. Arisi ◽  
D. Mayo ◽  
Z. Li ◽  
W. F. Ng ◽  
H. K. Moon ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Numerical Study ◽  
Horseshoe Vortex ◽  
Aerodynamic Characteristics ◽  
Secondary Flows ◽  
Navier Stokes ◽  
Vortex System ◽  
Ansys Fluent ◽  
Heat Transfer Augmentation ◽  
Exit Mach Number

A detailed experimental and numerical study has been conducted to investigate the endwall heat transfer characteristics on a nozzle platform that has been misaligned with the combustor exit, resulting in a backward facing step at the nozzle inlet. The study was carried out under transonic engine representative conditions with an exit Mach number of 0.85 (Reexit = 1.5 × 106), and an inlet turbulence intensity of 16%. A transient infrared thermography technique coupled with endwall static pressure ports, were used to map the endwall surface heat transfer and aerodynamic characteristics respectively. A numerical study was also conducted by solving the steady state Reynolds Averaged Navier Stokes (RANS) equations using the commercial CFD solver ANSYS Fluent v.15. The numerical results were then validated by comparing to experiment data and good agreement was observed. The results reveal that the classical endwall secondary flows (endwall crossflows, horseshoe and passage vortices) are weakened and a unique auxiliary vortex system develops within the passage and interacts with the weakened horseshoe vortex. It is observed that heat transfer in the first half of the passage endwall is heavily influenced by this auxiliary vortex system. Heat transfer augmentation of between 15% and 40% was also observed throughout the NGV endwall. Furthermore, the auxiliary vortex system results in a delayed cross-passage migration of the horseshoe vortex which consequently results in large lateral gradient in heat transfer downstream of the throat.

scholarly journals Laminar Forced Convective Heat Transfer and Fluid Flow in a Finned Cylindrical Annulus

2017 ◽  
Vol 2 (1) ◽  
Author(s):  
Isaac K Adegun ◽  
Olalekan A Olayemi ◽  
Temidayo S Jolayemi ◽  
Oladapo T Ogunbodede
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Fluid Flow ◽  
Energy Transport ◽  
Numerical Study ◽  
Bulk Temperature ◽  
Uniform Heat Flux ◽  
Heat Transfer Augmentation ◽  
Cylindrical Annulus ◽  
Flow Variables

The purpose of this paper is to numerically investigate the effects of some geometric parameters and flow variables on heat transfer augmentation in annuli with equi-spaced internal longitudinal fins along the external walls. A fully developed flow and a constant thermal boundary condition of uniform heat flux at the walls of the pipe were assumed. Continuity, momentum and energy transport equations were adopted for the solutions of the problem. A Q-BASIC code was written based on the finite difference scheme generated. Numerical experiments were conducted to ascertain the effects of Reynolds number Re, radius ratio, R.R, Prandtl number Pr, fin height H, and pipe inclination, on the rate of heat transfer and fluid flow. The results obtained show that for 50 ≤ Re ≤ 500, total Nusselt number NuT increases with increase in Re while for Re > 500, there was no significant increase in NuT. Nusselt number, average velocity and bulk temperature of the fluid increase with increasingin the range 0° ≤ ≤ 75° but for the range 75°≤  ≤ 90°  the effect is negligible. For R.R > 0.6, the heat transfer was observed to be almost independent of R; therefore for economic purposes, heat exchangers similar to the configuration studied should be run at a low pumping power. A numerical study was done to validate the program by test running it for the finless annuli for similar boundary conditions; the results obtained in the present work show the same trend as that of Kakac and Yucel.

scholarly journals Modelling and Numerical simulation of Nano-enhanced PV-PCM System for Heat Transfer Augmentation from the Panel

2021 ◽  
Vol 2054 (1) ◽  
pp. 012051
Author(s):  
B Charles Divyateja ◽  
K S Unnikrishnan ◽  
B Rohinikumar
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Phase Change Materials ◽  
Numerical Study ◽  
Liquid Fraction ◽  
Energy Conversion Efficiency ◽  
Solid Particles ◽  
Heat Transfer Augmentation ◽  
Solar Radiation Flux ◽  
Direct Energy

Abstract Phase change materials (PCMs) can effectively cool photovoltaic (PV) panels by the passive cooling technique, thereby enhancing its direct energy conversion efficiency. However, generally, PCMs have low thermal conductivity, and different methods can be employed to improve the heat transfer rate. Cooling techniques based on phase change materials (PCMs) enhanced by nano-sized solid particles are very promising. In this paper, a mathematical model is developed to simulate the performance analysis of PV attached with nano-enhanced PCM (NEPCM) integrated with fins and compare the same with that of pure PCM case. The system is oriented in a horizontal position and subjected to constant solar radiation flux of 1000 W/m 2. The PCM selected is RT25HC, and the nanoparticle used is CuO for the numerical study. The effects of volumetric concentrations (0%, 2%, and 4%) and fin number on the performance of the system are investigated numerically. Results show that adding nanoparticles is more effective in no fin case compared to finned cases. The maximum reduction in average PV temperature of 2.02 °C is obtained for no fin case with the nanoparticles’ volumetric concentration of 4%. Further enhancement in liquid fraction and energy storage in NEPCM is also achieved compared to the pure PCM system.

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