Numerical investigation of simultaneous effects of nanofluid flow and porous baffle on thermal energy transfer and flow features in a circular channel

2021 ◽  
pp. 1-21
Author(s):  
Hossein Namadchian ◽  
Javad Sodagar Abardeh ◽  
Ahmad Arabkoohsar ◽  
K.A.R. Ismail
Keyword(s):  
Porous Medium ◽  
Energy Transfer ◽  
Thermal Energy ◽  
Simple Algorithm ◽  
Darcy Number ◽  
Circular Channel ◽  
Axially Symmetric ◽  
Nanofluid Flow ◽  
Two Phase ◽  
Porous Region

Abstract In the present work, the forced-convection heat transfer features of different nanofluids in a circular channel with porous baffles are numerically investigated. Nanofluid flow in the porous area is simulated by the simultaneous use of Darcy-Brinkman-Forchheimer and two-phase mixture models. The flow is considered to be laminar, two-dimensionall, steady, axially symmetric, and incompressible. The simulations are conducted in Fluent software and by using the finite volume method and SIMPLE algorithm. The influences of various parameters, including Reynolds number, volume fractions of nanoparticles, Darcy number, porous region height, and various nanofluid types on the nanofluid flows and their thermal energy transfer features, are investigated. Results show that porous blocks significantly change the flow characteristics and thermal energy transfer features. For instance, at low Darcy numbers, the permeability of the porous region decreases, and the porous baffles have greater resistance against the nanofluid flow. As a result, the vortex area becomes stronger and taller, and streamlines near obstacles are tighter. However, in high Darcy numbers, due to the high permeability of the porous medium, the flow will be the same as the flow in the channel without barriers, and the porous baffles will not have much influence on the flow. For example, at Darcy number Da = 10-4 the vortex area almost disappears. The growth of conductivity ratio increases the local Nu in the vicinity of the barriers. Properties of the porous medium and nanofluid flow affect the thermal energy transfer rate, and it can be improved by making appropriate changes to these features.

Laminar Filmwise Condensation on Horizontal Disk Embedded in Porous Medium With Suction at Wall

2008 ◽  
Vol 130 (7) ◽  
Author(s):  
Tong-Bou Chang
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Liquid Film ◽  
Mechanical Energy ◽  
Disk Surface ◽  
Darcy Number ◽  
Nonlinear Ordinary Differential Equation ◽  
Phase Zone ◽  
Two Phase ◽  
Suction Parameter

This study performs a theoretical investigation into the problem of two-dimensional steady filmwise condensation flow on a horizontal disk embedded in a porous medium layer with suction at the disk surface. The analysis considers the case of a water-vapor system and is based on typical values of the relevant dimensional and dimensionless parameters. Due to the effects of capillary forces, a two-phase zone is formed between the liquid film and the vapor zone. The minimum mechanical energy concept is employed to establish the boundary condition at the edge of the horizontal disk and the Runge–Kutta shooting method is used to solve the second-order nonlinear ordinary differential equation of the liquid film. It is found that the capillary force and wall suction effects have a significant influence on the heat transfer performance. Specifically, the results show that the dimensionless heat transfer coefficient depend on the Darcy number Da, the Jacob number Ja, the effective Rayleigh number Rae, the effective Prandtl number Pre, the suction parameter Sw, and the capillary parameter Boc.

Parallel Simulations of CO2 Sequestration Using a Non-Isothermal Compositional Model

2008 ◽  
Author(s):  
Mojdeh Delshad ◽  
Sunil G. Thomas ◽  
Mary F. Wheeler
Keyword(s):  
Energy Transfer ◽  
Thermal Energy ◽  
Oil Recovery ◽  
Co2 Sequestration ◽  
Mixed Finite Element ◽  
Mixed Finite Element Method ◽  
Benchmark Problems ◽  
Two Phase ◽  
Pressure System ◽  
Compositional Model

This paper describes an efficient and parallel numerical scheme for multiphase compositional flow. The underlying theory is first presented followed by a brief description of the equation of state (EOS) and the two-phase flash implementation. An iterative “implicit-pressure and explicit-concentrations” (IMPEC) algorithm is then applied to enforce a non-linear volume balance (saturation) constraint. The pressure system is solved using a mixed finite element method, while the concentrations are updated explicitly in a manner that preserves local mass balance of every component. A major application of this scheme is in the modeling of field scale CO2 sequestration, as an enhanced oil recovery (EOR) process or for storage in deep saline aquifers. Thermal energy transfer also plays an important role in such problems since it can effect the phase properties dramatically. Hence, accurate and locally conservative methods are desirable to model the thermal effects. To this end, the paper also presents a time-split scheme for modeling thermal energy transfer which is sequentially coupled to flow. Finally, some numerical results are presented for challenging benchmark problems.

scholarly journals Impacts of the Properties Heterogeneity on 3D Magnetic Dusty Nanofluids Flow Within Cubic Porous Enclosures Contain Isothermal Cylinders

2021 ◽  
Author(s):  
Z. Z. Rashed
Keyword(s):  
Porous Medium ◽  
Three Dimensional ◽  
Thermal Conditions ◽  
Circular Cylinders ◽  
Nanofluid Flow ◽  
Two Phase ◽  
Flow Domain ◽  
Isothermal Cylinders ◽  
The Right ◽  
Volume Method

Abstract This paper examines the controlling of the three dimensional dusty nanofluid flow using the two circular cylinders having different thermal conditions. The cylinders are located in the middle area while the location of the right cylinder is changeable. The 3D cubic flow domain is filled by a non-Darcy porous medium and a magnetic field in Z-direction is taken place. The non-homogeneous two phase model of the nanofluid is applied while the permeability and thermal conductivity of the porous medium are assumed heterogonous. The current situation is represented by two systems of the equations for the nanofluid and dusty phases. The solutions methodology is depending on the 3D SIMPLE scheme together with the finite volume method. The major outcomes indicating to that the flow can be well controlled using the inner isothermal cylinders. Also, the cases of the heterogeneity in \(X-Y\) and \(X-Z\) directions give the lowest values of \({Nu}_{av}\).

Augmentation and Optimization of Heat Transfer in Reciprocating Flows Through Small-Scaled Channels Partially Filled With a Porous Medium

2008 ◽  
Author(s):  
H. Shokouhmand ◽  
K. Haibbi ◽  
A. Mosahebi
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Pressure Gradient ◽  
Fluid Velocity ◽  
Darcy Number ◽  
Result Section ◽  
Porous Region ◽  
Alternating Direction ◽  
Optimum Depth ◽  
Reciprocating Flow

This paper presents the effect of introducing a porous medium on the heat transfer by a reciprocating flow in a small-scaled two-dimensional channel. The channel is discretely heated from above and is insulated in the bottom. In this ideal geometry, a fully developed reciprocating flow is established by a sinusoidal pressure gradient. In side boundaries, velocity and temperature are assumed to be periodic. A certain volume of this channel is occupied by a porous medium which is shown to be an effecting tool for heat transfer augmentation. The results of this study are declared by some dimensionless parameters such as Womersley number (α), Darcy number (Da), porosity (ε), Prandtl number (Pr), Pressure gradient amplitude (A) and dimensionless characteristic lengths in the channel and porous medium. Heat transfer enhancement in presence of a porous medium is investigated in this study. Despite decreasing the fluid velocity in porous media, a high conductivity of such media can effectively enhance the heat transfer rate and because of these two contradictory effects, an optimum depth for the porous region is expected. For this purpose, at first the momentum equations of the domain are solved analytically (Brinkmann-extended Darcy model is used for porous region) and on the other hand the energy equation is investigated and solved numerically using Alternating Direction Implicit (ADI) method. The enhancing effect and optimization criteria are discussed in result section.

scholarly journals Analysis of the forced convection of two-phase Ferro-nanofluid flow in a completely porous microchannel containing rotating cylinders

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hamidreza Aghamiri ◽  
Mohammadreza Niknejadi ◽  
Davood Toghraie
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Porous Medium ◽  
Forced Convection ◽  
Entropy Generation ◽  
Volume Fraction ◽  
Rotating Cylinders ◽  
Nanofluid Flow ◽  
Two Phase ◽  
Porosity Percentage

AbstractIn the present work, the forced convection of nanofluid flow in a microchannel containing rotating cylinders is investigated in different geometries. The heat flux applied to the microchannel wall is 10,000 W m−2. The effects of Reynolds number, the volume fraction of nanoparticles, and the porosity percentage of the porous medium are investigated on the flow fields, temperature, and heat transfer rate. Reynolds number values vary from Re = 250–1000, non-dimensional rotational velocities 1 and 2, respectively, and volume fraction of nanoparticles 0–2%. The results show that increasing the velocity of rotating cylinders increases the heat transfer; also, increasing the Reynolds number and volume fraction of nanoparticles increases the heat transfer, pressure drop, and Cf,ave. By comparing the porosity percentages with each other, it is concluded that due to the greater contact of the nanofluid with the porous medium and the creation of higher velocity gradients, the porosity percentage is 45% and the values of are 90% higher than the porosity percentage. Comparing porosity percentages with each other, at porosity percentage 90% is greater than at porosity percentage 45%. On the other hand, increasing the Reynolds number reduces the entropy generation due to heat transfer and increases the entropy generation due to friction. Increasing the volume fraction of nanoparticles increases the entropy generations due to heat transfer and friction.

Peristaltic Carreau-Yasuda nanofluid flow and mixed heat transfer analysis in an asymmetric vertical and tapered wavy wall channel

2020 ◽  
Vol 1 (1) ◽  
pp. 128-140 ◽  
Author(s):  
Mohammad Hatami ◽  
◽  
D Jing ◽  
Keyword(s):  
Heat Transfer ◽  
Least Square Method ◽  
Weissenberg Number ◽  
Least Square ◽  
Heat Transfer Analysis ◽  
Phase Method ◽  
Nanofluid Flow ◽  
Two Phase ◽  
Nanoparticles Concentration ◽  
The Right

In this study, two-phase asymmetric peristaltic Carreau-Yasuda nanofluid flow in a vertical and tapered wavy channel is demonstrated and the mixed heat transfer analysis is considered for it. For the modeling, two-phase method is considered to be able to study the nanoparticles concentration as a separate phase. Also it is assumed that peristaltic waves travel along X-axis at a constant speed, c. Furthermore, constant temperatures and constant nanoparticle concentrations are considered for both, left and right walls. This study aims at an analytical solution of the problem by means of least square method (LSM) using the Maple 15.0 mathematical software. Numerical outcomes will be compared. Finally, the effects of most important parameters (Weissenberg number, Prandtl number, Brownian motion parameter, thermophoresis parameter, local temperature and nanoparticle Grashof numbers) on the velocities, temperature and nanoparticles concentration functions are presented. As an important outcome, on the left side of the channel, increasing the Grashof numbers leads to a reduction in velocity profiles, while on the right side, it is the other way around.

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