Numerical analysis of entropy generation in concentric curved annular ducts

Küçük, Haydar

doi:10.1007/s12206-010-0629-4

Cited by 20 publications

(7 citation statements)

References 32 publications

(60 reference statements)

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“…The length and width of the cross-section are ℎ(𝑚) and 𝑑(𝑚),respectively. The governing equations for the mathematical model are given by Kucuk [41] and Gyves [42] as follows:…”

Section: Mathematical Modelmentioning

confidence: 99%

Magnetohydrodynamic Effect on Two-Phase Flow in the porous medium through a Rectangular Curved Duct

Rahman

Parvin

Khan

2022

Preprint

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For the best structure and reliable maintenance, two- or multiphase flow is becoming more and more essential in engineering systems. However, a variety of different of biological organisms and natural phenomena that exhibit two-phase situations can be explored to improve our knowledge of this. This is so because current industrial technology does not place these limitations. This research aims to investigate the effect of an external magnetic field on unsteady laminar incompressible two-phase flow in a porous medium via a rectangular curved duct. The relevant governing equations are represented by the Navier-Stokes equations and by the Level set equation with boundary conditions. Fluid flow through curved rectangular ducts behaves differently from fluid flow through straight ducts due to the centrifugal action generated by duct curvature. Within curved ducts, centrifugal force is generated secondary flow vortices and spiraling fluid motion. This analysis graphically depicts the fluid phase distribution, the Dean vortex, velocity contours, and fluid volume fractions. Furthermore, displayed are the effects of the aspect ratio, porosity, Dean number, radius of curvature, and Hartmann number. Additionally, a comparison of two-phase flow between various fluids is presented.

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“…The length and width of the cross-section are ℎ(𝑚) and 𝑑(𝑚),respectively. The governing equations for the mathematical model are given by Kucuk [41] and Gyves [42] as follows:…”

Section: Mathematical Modelmentioning

confidence: 99%

Magnetohydrodynamic Effect on Two-Phase Flow in the porous medium through a Rectangular Curved Duct

Rahman

Parvin

Khan

2022

Preprint

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“…Their results deduced that the secondary flows, which result from the impact of centrifugal forces, affect the patterns of velocity and temperature in the annular geometry, wherein the viscous forces become more effective upon centrifugal forces while the annulus dimension ratio (width or height of the square curved ducts) decreases. After 1 year, Kucuk 32 reported a numerical analysis to simulate entropy generation in concentric curved annular square ducts under a constant surface temperature. Local and overall entropy generation in the entire flow field were analyzed in detail.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of hydrothermal behavior in a concentric curved annular tube

2020

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This study performs a numerical investigation of the steady‐state fully developed laminar flow and forced convection heat transfer characteristics in a concentric curved annular tube with two different curvature angles, a 90°‐bend annular tube and a U‐bend annular tube. A wide range of aspect ratios (r* = 0.1, 0.25, 0.5, and 0.75) and three curvature ratios (δc = 0.1, 0.2, and 0.5) were adopted in this study. The governing equations consisting of continuity, momentum, and energy equations are solved by considering the outer wall to be insulated (adiabatic), and a constant temperature is applied at the inner wall by using the finite‐volume method (FVM) to investigate the hydrothermal performance for these two different bend angles.Features of axial velocity contours, temperature patterns, and secondary flow streamlines at different cross‐sectional locations along the angular coordinate of curved annulus are observed with a Dean number range of (De = 32‐632). Additionally, the circumferential friction factor and averaged Nusselt number are obtained along the concentric curved annulus flow direction. The numerical results indicate that the normalized average Nusselt number and Performance Evaluation Criteria (PEC) increase with increasing De and curvature ratio for both curvature angles of concentric curved annular tube. Moreover, the normalized average Nusselt number, normalized friction factor‐Reynolds number product, and PEC increase with decreasing the aspect ratio because the annular gap between the surfaces of the inner and outer tubes (the boundaries of annulus) increases with decreasing aspect ratio. The hydrothermal performance of the concentric curved annular tube is higher than that of the straight annular tube attributed to the formation of secondary flows (Dean's vortices) in a cross‐sectional direction and the impact of the inner tube wall boundary. The value of PEC for both curvature angles of the curved annular tube at aspect ratio = 0.1 and De = 632 is approximately two‐fold of the straight annular tube under the same conditions while at aspect ratio = 0.75, it increases by nearly 80%.

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“…The vertical right and left side walls of the cavity were maintained at constant cold temperatures and the lower wall was subjected to a constant hot temperature, while the upper one was considered insulated. Kucuk (2010) presented a numerical analysis of entropy generation in concentric curved annular ducts with a constant wall temperature boundary condition. As Dean Number increased, the distribution of volumetric entropy generation resulting from heat transfer irreversibility and the total volumetric entropy generation was formed by the temperature field depending on the curvature under constant wall temperature boundary condition.…”

Section: Introductionmentioning

confidence: 99%

Entropy Generation Analysis of a Natural Convection Inside a Sinusoidal Enclosure With Different Shapes of Cylinders

Ali¹,

Jassim²,

Al-Amir³

et al. 2019

Frontiers in Heat and Mass Transfer

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This study is focused on the entropy generation of laminar natural convection inside a sinusoidal enclosure filled with air (Pr=0.71). The numerical investigation is performed for three shapes of inner cylinders (circle, square, and equilateral triangle) with the same area and different values of the Rayleigh number (10 3 -10 6 ). Galerkin Finite Element Approach is utilized to solve the governing equations. The results showed that the entropy generations due to heat transfer, fluid friction and total entropy generation increase with increasing values of Rayleigh number, while the local Bejan number decreases.

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Numerical analysis of entropy generation in concentric curved annular ducts

Cited by 20 publications

References 32 publications

Magnetohydrodynamic Effect on Two-Phase Flow in the porous medium through a Rectangular Curved Duct

Magnetohydrodynamic Effect on Two-Phase Flow in the porous medium through a Rectangular Curved Duct

Numerical simulation of hydrothermal behavior in a concentric curved annular tube

Entropy Generation Analysis of a Natural Convection Inside a Sinusoidal Enclosure With Different Shapes of Cylinders

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