Forced Convection Flow in a Wavy Channel With a Linearly Increasing Waviness at the Entrance Region

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Esam M. Alawadhi
Keyword(s):  
Pressure Drop ◽  
Thermal Characteristics ◽  
Reynolds Numbers ◽  
Entrance Region ◽  
Convection Flow ◽  
Wavy Wall ◽  
The Finite Element Method ◽  
Wavy Channel ◽  
Flow And Heat Transfer ◽  
Developing Flow

This research studies the fluid flow and heat transfer in a wavy channel with a linearly increasing waviness at the entrance region. The considered model consists of a channel formed by two wavy plates described by a sinusoidal profile and maintained at a uniform temperature. The finite element method is utilized to solve the problem. Reynolds numbers are considered in the range of 125<Re<1000 to avoid unsteady flow, and Pr=0.7. The global objective of this research is to reduce the pressure drop in the wavy channel due to the developing flow at the entrance region. The effect of the Reynolds number, length of the increasing waviness region, waviness of the wavy wall on the hydrodynamics, and thermal characteristics of the channel is investigated. The result indicates that the linearly increasing waviness at the entrance region significantly reduces the pressure drop in the channel on the other hand, the thermal characteristics of the wavy wall are nearly unaffected.

scholarly journals Mixed convection flow and heat transfer in a double lid- driven cavity containing a heated square block in the center

2020 ◽  
Vol 330 ◽  
pp. 01010
Author(s):  
Asma Ouahouah ◽  
Seddik Kherroubi ◽  
Abderrahmane Bourada ◽  
Nabila Labsi ◽  
Youb Khaled Benkahla
Keyword(s):  
Heat Transfer ◽  
Mixed Convection ◽  
Thermal Characteristics ◽  
Reynolds Numbers ◽  
Convection Flow ◽  
Square Cavity ◽  
Driven Cavity ◽  
Flow And Heat Transfer ◽  
Laminar Mixed Convection ◽  
Vertical Walls

In the present work, laminar mixed convection of a Newtonian fluid around a hot obstacle in a square cavity with moving vertical walls is studied numerically. The objective of this study is to analyze the effect of the Richardson number (0 ≼ Ri ≼ 10) and Reynolds number (50 ≼ Re ≼ 500) on both hydrodynamic and thermal characteristics around a hot obstacle in the enclosure. The analysis of the obtained results shows that the heat transfer is enhanced for high values of Richardson and Reynolds numbers.

scholarly journals Transport Phenomenon of Simultaneously Developing Flow and Heat Transfer in Twisted Sinusoidal Wavy Microchannel under Pulsating Inlet Flow Condition

2019 ◽  
Vol 128 ◽  
pp. 01011 ◽  
Author(s):  
Suvanjan Bhattacharyya ◽  
Sampad Gobinda Das ◽  
Himadri Chattopadhyay ◽  
Ali Cemal Benim ◽  
M. A. Moghimi
Keyword(s):  
Heat Transfer ◽  
Transport Phenomenon ◽  
Pressure Drop ◽  
Heat Transfer Performance ◽  
Reynolds Numbers ◽  
Transfer Performance ◽  
Mems Devices ◽  
Governing Equations ◽  
Flow And Heat Transfer ◽  
Developing Flow

The transport phenomena in microchannel are significant in designing MEMS devices. The current study investigates numerically the simultaneously developing unsteady laminar flow and heat transfer inside a twisted sinusoidal wavy microchannel. At the inlet sinusoidal varying velocity component is applied. Varying pulsating amplitude and frequency represented by the Strouhal number was studied for Reynolds numbers ranging from 1 to 100. The governing equations are solved with a finite volume based numerical method. In comparison with steady flow, it was found that imposed sinusoidal velocity at the inlet can provide improved heat transfer performance at different amplitudes and frequencies while keeping the pressure drop within acceptable limits.

scholarly journals Entropy Generation and Natural Convection Flow of Hybrid Nanofluids in a Partially Divided Wavy Cavity Including Solid Blocks

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2942 ◽  
Author(s):  
Ammar I. Alsabery ◽  
Ishak Hashim ◽  
Ahmad Hajjar ◽  
Mohammad Ghalambaz ◽  
Sohail Nadeem ◽  
...  
Keyword(s):  
Entropy Generation ◽  
Convection Flow ◽  
Hybrid Nanofluid ◽  
Bejan Number ◽  
The Finite Element Method ◽  
Governing Equations ◽  
Flow And Heat Transfer ◽  
Hybrid Nanofluids ◽  
Wavy Cavity ◽  
Rayleigh Numbers

The present investigation addressed the entropy generation, fluid flow, and heat transfer regarding Cu-Al 2 O 3 -water hybrid nanofluids into a complex shape enclosure containing a hot-half partition were addressed. The sidewalls of the enclosure are made of wavy walls including cold isothermal temperature while the upper and lower surfaces remain insulated. The governing equations toward conservation of mass, momentum, and energy were introduced into the form of partial differential equations. The second law of thermodynamic was written for the friction and thermal entropy productions as a function of velocity and temperatures. The governing equations occurred molded into a non-dimensional pattern and explained through the finite element method. Outcomes were investigated for Cu-water, Al 2 O 3 -water, and Cu-Al 2 O 3 -water nanofluids to address the effect of using composite nanoparticles toward the flow and temperature patterns and entropy generation. Findings show that using hybrid nanofluid improves the Nusselt number compared to simple nanofluids. In the case of low Rayleigh numbers, such enhancement is more evident. Changing the geometrical aspects of the cavity induces different effects toward the entropy generation and Bejan number. Generally, the global entropy generation for Cu-Al 2 O 3 -water hybrid nanofluid takes places between the entropy generation values regarding Cu-water and Al 2 O 3 -water nanofluids.

scholarly journals Numerical Investigation on the Fluid Flow and Heat Transfer in the Entrance Region of Wavy Channel

2013 ◽  
Vol 36 ◽  
pp. 76-85 ◽  
Author(s):  
Nabou Mohamed ◽  
Biara Ratiba Wided ◽  
El Mir Mohamed ◽  
Missoum Abd el karim ◽  
Bouanini Mohamed
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Numerical Investigation ◽  
Entrance Region ◽  
Wavy Channel ◽  
Flow And Heat Transfer

scholarly journals Influence of wall waviness on friction and pressure drop in channels

1981 ◽  
Vol 4 (4) ◽  
pp. 805-818 ◽  
Author(s):  
K. Vajravelu ◽  
Ali H. Nayfeh
Keyword(s):  
Pressure Drop ◽  
Flow Behavior ◽  
Reynolds Numbers ◽  
Wavy Wall ◽  
Governing Equations ◽  
Short Waves ◽  
Gradient Parameter ◽  
Arbitrary Amplitude ◽  
Wavy Channels ◽  
Good Agreement

An attention has been given to investigate the flow behavior of an incompressible viscous fluid confined in horizontal wavy channels and set in motion due to the movement of the upper wall and the pressure differences. The governing equations have been solved analytically as well as numerically subject to the relevant boundary conditions by assuming that the solution consists of two parts: a mean part and a disturbance or perturbed part. For small and moderate Reynolds numbers, the analytical solution for the perturbed part has been found to be in good agreement with the numerical one. The effects of Reynolds number, the pressure gradient parameter, and the undulation wavenumber on friction and pressure drop are found to be quite significant. In addition to the flow behavior for both long and short waves and for large Reynolds numbers, the effect of the wall waviness on friction and pressure drop has been examined for any arbitrary amplitude of the wavy wall.

Turbulent Flow and Heat Transfer in the Entrance Region of a Parallel Wall Passage

1969 ◽  
Vol 184 (1) ◽  
pp. 697-712 ◽  
Author(s):  
J. Byrne ◽  
A. P. Hatton ◽  
P. G. Marriott
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Entrance Region ◽  
Fully Developed Flow ◽  
Law Of The Wall ◽  
Flow And Heat Transfer ◽  
Developing Flow ◽  
Boundary Layer Development ◽  
Parallel Wall ◽  
Made In

Measurements of boundary layer development and heat transfer were made in the entrance region of a parallel passage and compared with a computer solution based on the law of the wall. Little difference was found between the heat transfer, both measured and predicted, with a developing flow and that predicted with a fully developed flow. The experiments also show that boundary layer parameters, such as momentum thickness, do not approach their fully developed values asymptotically.

Numerical Study of Developing Flow and Heat Transfer in a Wavy Passage

1999 ◽  
Vol 121 (4) ◽  
pp. 713-719 ◽  
Author(s):  
K. Stone ◽  
S. P. Vanka
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Numerical Study ◽  
Spatial Location ◽  
Reynolds Numbers ◽  
Low Reynolds Numbers ◽  
The Core ◽  
Flow And Heat Transfer ◽  
Developing Flow ◽  
Energy Equations

Developing flow and heat transfer in a wavy passage are studied using a numerical scheme that solves the two-dimensional unsteady flow and energy equations. Calculations are presented for a wavy channel consisting of 14 waves. Time-dependent simulations have been performed for several Reynolds numbers. At low Reynolds numbers, the flow is steady in the complete channel. As the Reynolds number is progressively increased, the flow becomes unsteady. As a result of the unsteadiness, there is increased mixing between the core and the wall fluids, thereby increasing the heat transfer rate. With further increase in Reynolds number, the flow becomes unsteady at a much earlier spatial location.

Flow in a Corrugated Channel With Multiple Heat Sources

2008 ◽  
Author(s):  
Esam M. Alawadhi
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Reynolds Numbers ◽  
Heat Sources ◽  
The Finite Element Method ◽  
Transfer Enhancement ◽  
Wavy Channel ◽  
Discrete Heat Sources ◽  
Minimum Cross Section ◽  
High Reynolds

Numerical method based on the finite element method is utilized to study the heat transfer enhancement from discrete heat sources using a wavy channel. The considered geometry consists of a channel formed by two wavy plates with six discrete heat sources placed on upper and lower walls. The effect of the Reynolds number, Prandtl number, waviness of the wavy wall, and the location of the heat sources on the heat transfer out of the heat sources is investigated. The result indicates that the wavy channel significantly enhances the heat flow out of the heat sources, and heat sources located at the minimum cross section areas of the channel shows the best performance. The heat transfer enhancement can reaches as high as 120% for high Reynolds numbers and waviness of the channel.

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