scholarly journals A Numerical Study on Heat Transfer in the Channel with Delta Winglet Pair Vortex Generators

2021 ◽  
Vol 39 (4) ◽  
pp. 1305-1312
Author(s):  
Mohammad Mazidi Sharfabadi ◽  
Parham Mobadersani ◽  
Leila Nourpour
Keyword(s):  
Heat Transfer ◽  
Aspect Ratio ◽  
Numerical Study ◽  
Rectangular Channel ◽  
Flow Characteristics ◽  
Vortex Generators ◽  
Hydrodynamic Performance ◽  
Hydrodynamic Characteristics ◽  
Quick Scheme ◽  
Volume Method

In this study, the effect of the vortex generators on the heat transfer and flow characteristics in a rectangular channel is investigated numerically by finite volume method. The governing equations are discretized using QUICK scheme. The numerical results are validated against published experimental data. In this paper, the effects of the winglet aspect ratio and the distance between the vertices of the winglets on the heat transfer and hydrodynamic characteristics of the flow are surveyed. In addition, to achieve the optimum amount of heat transfer, it is important to know the proper arrangement of the triangular winglet pairs as well as their suitable position. Therefore, the appropriate values of the longitudinal and transverse pitch are presented in this paper. The results show that the winglet with the aspect ratio of 1.75 has the best thermal and hydrodynamic performance. Furthermore, the transverse pitch of 1.24 causes 6.5% growth in the average Nusselt number.

scholarly journals 2D Numerical Study of Heat Transfer Enhancement Using Fish-Tail Locomotion Vortex Generators

2021 ◽  
Vol 8 (3) ◽  
pp. 386-392
Author(s):  
Ahmed Hashim Yousif ◽  
Hakim T. Kadhim ◽  
Kadhim K. Idan Al-Chlaihawi
Keyword(s):  
Heat Transfer ◽  
Friction Factor ◽  
Numerical Study ◽  
Rectangular Channel ◽  
Flow Characteristics ◽  
Vortex Generators ◽  
Transfer Enhancement ◽  
Number Range ◽  
Maximum Value ◽  
Fluid Flow Characteristics

In this paper, a numerical simulation is performed to study the effect of two types of concave vortex generators (VGs), arranged as fish-tail locomotion in a rectangular channel. The heat transfer and fluid flow characteristics with and without VGs are examined over the Reynolds number range 200≤Re≤2200.The two proposed types of the VGs are selected based on the speed of the fish movement which is arranged in different distances between them (d/H=0.6, 1, 1.3). The results show that the use of VGs can significantly enhance the heat transfer rate, but also increases the friction factor. The heat transfer performance is enhanced by (4-21.1%) reaching the maximum value by using the first type of the VGs at (d/H=1.3) due to better mixing of secondary flow and the new arrangement of the VGs which lead to decreasing the friction factor with an easy flow of fluid.

Flow Characteristics in a Three-Dimensional Rectangular Channel With a Pair of Ribs Placed Symmetrically at the Channel Walls

2000 ◽  
Author(s):  
M. Singh ◽  
P. K. Panigrahi ◽  
G. Biswas
Keyword(s):  
Heat Transfer ◽  
Large Scale ◽  
Numerical Study ◽  
Rectangular Channel ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Navier Stokes ◽  
Complex Flow ◽  
Energy Equations

Abstract A numerical study of rib augmented cooling of turbine blades is reported in this paper. The time-dependent velocity field around a pair of symmetrically placed ribs on the walls of a three-dimensional rectangular channel was studied by use of a modified version of Marker-And-Cell algorithm to solve the unsteady incompressible Navier-Stokes and energy equations. The flow structures are presented with the help of instantaneous velocity vector and vorticity fields, FFT and time averaged and rms values of components of velocity. The spanwise averaged Nusselt number is found to increase at the locations of reattachment. The numerical results are compared with available numerical and experimental results. The presence of ribs leads to complex flow fields with regions of flow separation before and after the ribs. Each interruption in the flow field due to the surface mounted rib enables the velocity distribution to be more homogeneous and a new boundary layer starts developing downstream of the rib. The heat transfer is primarily enhanced due to the decrease in the thermal resistance owing to the thinner boundary layers on the interrupted surfaces. Another reason for heat transfer enhancement can be attributed to the mixing induced by large-scale structures present downstream of the separation point.

scholarly journals Numerical Investigation of Heat Transfer and Fluid Flow Characteristics in a Rectangular Channel with Presence of Perforated Concave Rectangular Winglet Vortex Generators

2021 ◽  
Author(s):  
Syaiful ◽  
M. Kurnia Lutfi
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Rectangular Channel ◽  
Convection Heat Transfer ◽  
Flow Characteristics ◽  
Vortex Generator ◽  
Vortex Generators ◽  
Heated Plate ◽  
Convection Heat ◽  
Fluid Flow Characteristics

The high thermal resistance of the airside of the compact heat exchanger results in a low heat transfer rate. Vortex generator (VG) is one of the effective passive methods to increase convection heat transfer by generating longitudinal vortex (LV), which results in an increase in fluid mixing. Therefore, this study aims to analyze the convection heat transfer characteristics and the pressure drop of airflow in a rectangular channel in the presence of a concave rectangular winglet VG on a heated plate. Numerical calculations were performed on rectangular winglet pairs vortex generators (RWP VGs) and concave rectangular winglet pairs vortex generators (CRWP VGs) with a 45° angle of attack and one, two, and three pairs of VGs with and without holes. The simulation results show that the decrease in the value of convection heat transfer coefficient and pressure drop on CRWP with three perforated VG configuration is 4.63% and 3.28%, respectively, of the three pairs of CRWP VG without holes at an airflow velocity of 2 m/s.

Numerical Study of Flow and Heat Transfer in Rectangular Channel With Periodic Longitudinal Vortex Generators Under Pulsating Flow

2012 ◽  
Author(s):  
Lin Tian ◽  
Wei Bai ◽  
Shanhu Xue ◽  
Zipeng Huang ◽  
Qiuwang Wang
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Friction Factor ◽  
Numerical Study ◽  
Rectangular Channel ◽  
Vortex Generators ◽  
Longitudinal Vortex ◽  
Small Scale ◽  
Inlet Velocity ◽  
Flow And Heat Transfer

The unsteady turbulent flow and heat transfer in rectangular channel with periodic longitudinal vortex generators on up and bottom walls are investigated by standardized k-ε two equation turbulent model combined with standardized wall function which has been validated by steady experimental data. Influence of varying frequency and amplitude of inlet velocity varying by sine function on heat transfer and friction factor are discussed. It is found that parameters such as Tout, Tf, Tw, Nusselt number and the friction factor f vary with time periodically, phase difference occurred compared with inlet velocity. Pulsating frequency has little impact on time averaged Nusselt number. However, when amplitude increases from 0.2us to 0.8us, the heat transfer rate is augmented by about 4%. Furthermore, a critical frequency has been captured when amplitude equals to 0.8us for the channel studied. The current study will deepen understanding of unsteady flow in plate fuel assembly, which can be used in small-scale reactors.

The Effect of Triangular Vortex Generators on Turbulent Flow and Heat Transfer in a Channel

2010 ◽  
Author(s):  
Hosseinali Soltanipour ◽  
Iraj Mirzaei ◽  
Parisa Choupani
Keyword(s):  
Heat Transfer ◽  
Turbulent Flow ◽  
Rectangular Channel ◽  
Vortex Generators ◽  
Navier Stokes ◽  
Single Element ◽  
Longitudinal Vortices ◽  
Energy Equations ◽  
Volume Method ◽  
Physical Phenomena

In the present work heat transfer characteristics and flow structure in turbulent flow through a rectangular channel containing built-in triangular winglet-type vortex generators have been analyzed by means of solutions of the Navier-Stokes and energy equations using finite volume method. The geometrical configuration is representative of single element of plain-plate heat exchangers. Each winglet-pair induces longitudinal vortices behind it. Shear stress transport (SST) model is used in this study. The underlying physical phenomena have been described and the effects of Reynolds number and angle of attack, on the heat transfer, pressure drop and thermal performance have been presented.

Numerical study on significance of wave amplitude, wavelength and aspect ratio on heat transfer and fluid flow characteristics in circular wavy MC heat sink design

2021 ◽  
pp. 095440622198937
Author(s):  
Valaparla Ranjith Kumar ◽  
Karthik Balasubramanian ◽  
K Kiran Kumar
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Fluid Flow ◽  
Aspect Ratio ◽  
Wave Amplitude ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Uniform Heat Flux ◽  
Uniform Heat ◽  
Fluid Flow Characteristics

In this study, hydrothermal characteristics in a circular wavy microchannel (CWMC) design under laminar flow conditions with uniform heat flux is numerically studied. Parametric studies in an innovative CWMC design were carried out at various wave amplitudes, wavelengths and aspect ratios. Three dimensional numerical study was performed in the Reynolds number (Re) range from 100 to 300 with uniform heat flux (50 W/cm2) applied at bottom of the channel, treating copper as channel material and water as working fluid. The obtained results were compared to sinusoidal wavy microchannel (SWMC).The results showed that heat transfer and fluid flow characteristics were significantly influenced by wave amplitude, wavelength and aspect ratio. Velocity vectors and contours were presented to understand the heat transfer and fluid flow characteristics. Stream-wise local Nusselt number, overall performance factor, span-wise velocity and temperature variation are also presented. It is concluded that CWMC with higher wave amplitude, smaller wave length and smaller aspect ratio gives higher heat transfer augmentation with corresponding pressure drop penalty.

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