scholarly journals Modelling Study on Internal Energy Loss Due to Entropy Generation for Non-Darcy Poiseuille Flow of Silver-Water Nanofluid: An Application of Purification

Entropy ◽  
2018 ◽  
Vol 20 (11) ◽  
pp. 851 ◽  
Author(s):  
Nasir Shehzad ◽  
Ahmed Zeeshan ◽  
Rahmat Ellahi ◽  
Saman Rashidi
Keyword(s):  
Porous Media ◽  
Internal Energy ◽  
Entropy Generation ◽  
Poiseuille Flow ◽  
Volume Fraction ◽  
Low Cost ◽  
Theoretical Estimate ◽  
Industrial Process ◽  
Highly Nonlinear ◽  
Homotopy Analysis

In this paper, an analytical study of internal energy losses for the non-Darcy Poiseuille flow of silver-water nanofluid due to entropy generation in porous media is investigated. Spherical-shaped silver (Ag) nanosize particles with volume fraction 0.3%, 0.6%, and 0.9% are utilized. Four illustrative models are considered: (i) heat transfer irreversibility (HTI), (ii) fluid friction irreversibility (FFI), (iii) Joule dissipation irreversibility (JDI), and (iv) non-Darcy porous media irreversibility (NDI). The governing equations of continuity, momentum, energy, and entropy generation are simplified by taking long wavelength approximations on the channel walls. The results represent highly nonlinear coupled ordinary differential equations that are solved analytically with the help of the homotopy analysis method. It is shown that for minimum and maximum averaged entropy generation, 0.3% by vol and 0.9% by vol of nanoparticles, respectively, are observed. Also, a rise in entropy is evident due to an increase in pressure gradient. The current analysis provides an adequate theoretical estimate for low-cost purification of drinking water by silver nanoparticles in an industrial process.

scholarly journals Darcy-Forchheimer hybrid nanofluid flow over a stretching curved surface with heat and mass transfer

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0249434
Author(s):  
Anwar Saeed ◽  
Wajdi Alghamdi ◽  
Safyan Mukhtar ◽  
Syed Imad Ali Shah ◽  
Poom Kumam ◽  
...  
Keyword(s):  
Differential Equations ◽  
Ordinary Differential Equations ◽  
Volume Fraction ◽  
Curved Surface ◽  
Hybrid Nanofluid ◽  
Porous Space ◽  
Highly Nonlinear ◽  
Homotopy Analysis ◽  
Curvature Parameter ◽  
Swcnts And Mwcnts

The present article provides a detailed analysis of the Darcy Forchheimer flow of hybrid nanoliquid past an exponentially extending curved surface. In the porous space, the viscous fluid is expressed by Darcy-Forchheimer. The cylindrical shaped carbon nanotubes (SWCNTs and MWCNTs) and Fe3O4 (iron oxide) are used to synthesize hybrid nanofluid. At first, the appropriate similarity transformation is used to convert the modeled nonlinear coupled partial differential equations into nonlinear coupled ordinary differential equations. Then the resulting highly nonlinear coupled ordinary differential equations are analytically solved by the utilization of the “Homotopy analysis method” (HAM) method. The influence of sundry flow factors on velocity, temperature, and concentration profile are sketched and briefly discussed. The enhancement in both volume fraction parameter and curvature parameter k results in raises of the velocity profile. The uses of both Fe3O4 and CNTs nanoparticles are expressively improving the thermophysical properties of the base fluid. Apart from this, the numerical values of some physical quantities such as skin friction coefficients, local Nusselt number, and Sherwood number for the variation of the values of pertinent parameters are displayed in tabular forms. The obtained results show that the hybrid nanofluid enhances the heat transfer rate 2.21%, 2.1%, and 2.3% using the MWCNTs, SWCNTs, and Fe3O4 nanomaterials.

scholarly journals Investigation of Forced Convection Enhancement and Entropy Generation of Nanofluid Flow through a Corrugated Minichannel Filled with a Porous Media

Entropy ◽  
2020 ◽  
Vol 22 (9) ◽  
pp. 1008
Author(s):  
Ehsan Aminian ◽  
Hesam Moghadasi ◽  
Hamid Saffari ◽  
Amir Mirza Gheitaghy
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
Entropy Generation ◽  
Volume Fraction ◽  
Numerical Procedure ◽  
Numerical Data ◽  
Flow In Porous Media ◽  
Geometrical Parameters ◽  
Nanofluid Flow ◽  
Flow Through

Corrugating channel wall is considered to be an efficient procedure for achieving improved heat transfer. Further enhancement can be obtained through the utilization of nanofluids and porous media with high thermal conductivity. This paper presents the effect of geometrical parameters for the determination of an appropriate configuration. Furthermore, the optimization of forced convective heat transfer and fluid/nanofluid flow through a sinusoidal wavy-channel inside a porous medium is performed through the optimization of entropy generation. The fluid flow in porous media is considered to be laminar and Darcy–Brinkman–Forchheimer model has been utilized. The obtained results were compared with the corresponding numerical data in order to ensure the accuracy and reliability of the numerical procedure. As a result, increasing the Darcy number leads to the increased portion of thermal entropy generation as well as the decreased portion of frictional entropy generation in all configurations. Moreover, configuration with wavelength of 10 mm, amplitude of 0.5 mm and phase shift of 60° was selected as an optimum geometry for further investigations on the addition of nanoparticles. Additionally, increasing trend of average Nusselt number and friction factor, besides the decreasing trend of performance evaluation criteria (PEC) index, were inferred by increasing the volume fraction of the nanofluid (Al2O3 and CuO).

scholarly journals Entropy Generation Analysis of Peristaltic Flow and Heat Transfer of a Jeffery Nanofluid in a Horizontal Channel under Magnetic Environment

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Aneela Bibi ◽  
Hang Xu
Keyword(s):  
Thermal Radiation ◽  
Entropy Generation ◽  
Volume Fraction ◽  
Brownian Diffusion ◽  
Physical Parameters ◽  
Symmetric Channel ◽  
Flow And Heat Transfer ◽  
Heating Effects ◽  
Homotopy Analysis ◽  
Jeffery Nanofluid

A mathematical model is developed to examine the behaviors of a peristalsis flow with nanoparticles in a symmetric channel under the magnetic environment. Here, the nanofluid is electrically conducted through an external magnetic field. Thermal radiation and Joule heating effects are also retained in the present analysis. Under the lubrication approach, the reduced nonlinear systems are obtained. Then, they are solved very efficiently by means of a homotopy analysis method-based package BVPh 2.0. The influences of important physical parameters on the flow behaviors are presented. Analysis of the entropy generation is illustrated. It is found that the Brownian diffusion and the thermophoresis are the two most important nanoparticle slip mechanisms in the Jeffery fluids as well. Besides, the Hartman number, the type of the Jeffery fluid, the Brinkman number, and the thermal radiation parameter play important roles on flow behaviors. Results show that the temperature profile enhanced but the nanoparticles’ volume fraction profiles lowered with increase in the Hartman number. However, using the Jeffery nanofluid induces effect on the velocity distribution that decreases with the increase in the Jeffery fluid parameter. It is also found that the generated total entropy increases with an increase in the Brownian motion parameter but with a decrease in the thermophoresis parameter.

scholarly journals Design of Low-Cost and High-Strength Titanium Alloys Using Pseudo-Spinodal Mechanism through Diffusion Couple Technology and CALPHAD

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2910
Author(s):  
Chaoyi Ding ◽  
Chun Liu ◽  
Ligang Zhang ◽  
Di Wu ◽  
Libin Liu
Keyword(s):  
Diffusion Couple ◽  
Titanium Alloys ◽  
High Throughput ◽  
Volume Fraction ◽  
Raw Materials ◽  
Low Cost ◽  
High Strength ◽  
High Yield ◽  
Α Phase ◽  
Cr System

The high cost of development and raw materials have been obstacles to the widespread use of titanium alloys. In the present study, the high-throughput experimental method of diffusion couple combined with CALPHAD calculation was used to design and prepare the low-cost and high-strength Ti-Al-Cr system titanium alloy. The results showed that ultra-fine α phase was obtained in Ti-6Al-10.9Cr alloy designed through the pseudo-spinodal mechanism, and it has a high yield strength of 1437 ± 7 MPa. Furthermore, application of the 3D strength model of Ti-6Al-xCr alloy showed that the strength of the alloy depended on the volume fraction and thickness of the α phase. The large number of α/β interfaces produced by ultra-fine α phase greatly improved the strength of the alloy but limited its ductility. Thus, we have demonstrated that the pseudo-spinodal mechanism combined with high-throughput diffusion couple technology and CALPHAD was an efficient method to design low-cost and high-strength titanium alloys.

scholarly journals Dynamics with Cattaneo–Christov heat and mass flux theory of bioconvection Oldroyd-B nanofluid

2020 ◽  
Vol 12 (8) ◽  
pp. 168781402093046 ◽  
Author(s):  
Noor Saeed Khan ◽  
Qayyum Shah ◽  
Arif Sohail
Keyword(s):  
Mass Transfer ◽  
Porous Media ◽  
Differential Equations ◽  
Mass Flux ◽  
Homotopy Analysis Method ◽  
Two Dimensional ◽  
Analysis Method ◽  
Homotopy Analysis ◽  
Transfer Flow ◽  
Insight Into

Entropy generation in bioconvection two-dimensional steady incompressible non-Newtonian Oldroyd-B nanofluid with Cattaneo–Christov heat and mass flux theory is investigated. The Darcy–Forchheimer law is used to study heat and mass transfer flow and microorganisms motion in porous media. Using appropriate similarity variables, the partial differential equations are transformed into ordinary differential equations which are then solved by homotopy analysis method. For an insight into the problem, the effects of various parameters on different profiles are shown in different graphs.

Joining between Ceramics and Metal in Composite Pipes Fabricated by the SHS Metallurgical Process

2007 ◽  
Vol 280-283 ◽  
pp. 887-890
Author(s):  
Zhong Min Zhao ◽  
Long Zhang ◽  
Jian Jiang Wang ◽  
Shi Yan ◽  
Jin Rong Cao
Keyword(s):  
High Performance ◽  
Volume Fraction ◽  
Layer Structure ◽  
Mechanical Test ◽  
Steel Substrate ◽  
Low Cost ◽  
Metallurgical Process ◽  
Ni Powder ◽  
Suitable Amount ◽  
Composite Pipes

The design on joining of metal and ceramics in composite pipes fabricated by the SHS metallurgical process is carried on with adding (TiO2 +Al+C+Ni) subsystem in(CrO3+Al) system, and the composite pipes with three-layer structure of steel substrate, intermediate alloy and lined ceramics are fabricated with low cost and high performance. Combustion determination and mechanical test indicate that adding suitable amount of Ni powder in combustion system rather than (NiO+Al) subsystem can cause combustion behavior of a whole system and volume fraction of the carbides to be controlled easily, and is beneficial to improve joining of the intermediate alloy and steel substrate, causing compression strength and compression shear strength of the composite pipes to be increased greatly.

scholarly journals Non-Newtonian effect on heat transfer and entropy generation of natural convection nanofluid flow inside a vertical wavy porous cavity

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Mahbuba Tasmin ◽  
Preetom Nag ◽  
Zarin T. Hoque ◽  
Md. Mamun Molla
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Entropy Generation ◽  
Power Law ◽  
Volume Fraction ◽  
Local Entropy ◽  
Nanofluid Flow ◽  
Porosity Level ◽  
Power Law Index ◽  
Local Entropy Generation

AbstractA numerical study on heat transfer and entropy generation in natural convection of non-Newtonian nanofluid flow has been explored within a differentially heated two-dimensional wavy porous cavity. In the present study, copper (Cu)–water nanofluid is considered for the investigation where the specific behavior of Cu nanoparticles in water is considered to behave as non-Newtonian based on previously established experimental results. The power-law model and the Brinkman-extended Darcy model has been used to characterize the non-Newtonian porous medium. The governing equations of the flow are solved using the finite volume method with the collocated grid arrangement. Numerical results are presented through streamlines, isotherms, local Nusselt number and entropy generation rate to study the effects of a range of Darcy number (Da), volume fractions (ϕ) of nanofluids, Rayleigh numbers (Ra), and the power-law index (n). Results show that the rate of heat transfer from the wavy wall to the medium becomes enhanced by decreasing the power-law index but increasing the volume fraction of nanoparticles. Increase of porosity level and buoyancy forces of the medium augments flow strength and results in a thinner boundary layer within the cavity. At negligible porosity level of the enclosure, effect of volume fraction of nanoparticles over thermal conductivity of the nanofluids is imperceptible. Interestingly, when the Darcy–Rayleigh number $$Ra^*\gg 10$$ R a ∗ ≫ 10 , the power-law effect becomes more significant than the volume fraction effect in the augmentation of the convective heat transfer process. The local entropy generation is highly dominated by heat transfer irreversibility within the porous enclosure for all conditions of the flow medium. The particular wavy shape of the cavity strongly influences the heat transfer flow pattern and local entropy generation. Interestingly, contour graphs of local entropy generation and local Bejan number show a rotationally symmetric pattern of order two about the center of the wavy cavity.

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