Impact of nonlinear radiative nanoparticles on an unsteady flow of a Williamson fluid toward a permeable convectively heated shrinking sheet

2018 ◽  
Vol 15 (6) ◽  
pp. 731-742 ◽  
Author(s):  
Aurang Zaib ◽  
Rizwan Ul Haq ◽  
A.J. Chamkha ◽  
M.M. Rashidi
Keyword(s):  
Temperature Distribution ◽  
Solar Energy ◽  
Unsteady Flow ◽  
Fluid Velocity ◽  
Shrinking Sheet ◽  
Suction Parameter ◽  
Content Type ◽  
Williamson Fluid ◽  
The Impact ◽  
Accelerating Flow

PurposeThe study aims to numerically examine the impact of nanoparticles on an unsteady flow of a Williamson fluid past a permeable convectively heated shrinking sheet.Design/methodology/approachIn sort of the solution of the governing differential equations, suitable transformation variables are used to get the system of ODEs. The converted equations are then numerically solved via the shooting technique.FindingsThe impacts of such parameters on the velocity profile, temperature distribution and the concentration of nanoparticles are examined through graphs and tables. The results point out that multiple solutions are achieved for certain values of the suction parameter and for decelerating flow, while for accelerating flow, the solution is unique. Further, the non-Newtonian parameter reduces the fluid velocity and boosts the temperature distribution and concentration of nanoparticles in the first solution, while the reverse drift is noticed in the second solution.Practical implicationsThe current results may be used in many applications such as biomedicine, industrial, electronics and solar energy.Originality/valueThe authors think that the current results are new and significant, which are used in many applications such as biomedicine, industrial, electronics and solar energy. The results have not been considered elsewhere.

Three-dimensional flow of radiative hybrid nanofluid past a permeable stretching/shrinking sheet with homogeneous-heterogeneous reaction

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Najiyah Safwa Khashi'ie ◽  
Norihan Md Arifin ◽  
Natalia C. Rosca ◽  
Alin V. Rosca ◽  
Ioan Pop
Keyword(s):  
Heterogeneous Reaction ◽  
Three Dimensional ◽  
Heterogeneous Reactions ◽  
Shrinking Sheet ◽  
Hybrid Nanofluid ◽  
Three Dimensional Flow ◽  
Suction Parameter ◽  
Content Type ◽  
Fluid Concentration ◽  
The Stability

Purpose The purpose of this paper is to study the effects of thermal radiation and homogeneous-heterogeneous reactions in the three-dimensional hybrid nanofluid flow past a permeable stretching/shrinking sheet. Design/methodology/approach The combination of aluminum oxide (Al2O3) and copper (Cu) nanoparticles with total volumetric concentration is numerically analyzed using the existing correlations of hybrid nanofluid. With the consideration that both homogeneous and heterogeneous reactions are isothermal while the diffusion coefficients of both autocatalyst and reactant are same, the governing model is simplified into a set of differential (similarity) equations. Findings Using the bvp4c solver, dual solutions are presented, and the stability analysis certifies the physical/real solution. The findings show that the suction parameter is requisite to induce the steady solution for shrinking parameter. Besides, the fluid concentration owing to the shrinking sheet is diminished with the addition of surface reaction. Originality/value The present findings are novel and can be a reference point to other researchers to further analyze the heat transfer performance and stability of the working fluids.

scholarly journals Unsteady flow and heat transfer over a permeable stretching/shrinking sheet with generalized slip velocity

2018 ◽  
Vol 28 (6) ◽  
pp. 1457-1470 ◽  
Author(s):  
Mohd Ezad Hafidz Hafidzuddin ◽  
Roslinda Nazar ◽  
Norihan M. Arifin ◽  
Ioan Pop
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Unsteady Flow ◽  
Slip Velocity ◽  
Shrinking Sheet ◽  
Content Type ◽  
Flow And Heat Transfer ◽  
Polymer Sheets ◽  
Branch Solution ◽  
Layer Flow

Purpose This study aims to investigate the unsteady two-dimensional viscous flow and heat transfer over an unsteady permeable stretching/shrinking sheet (surface) with generalized slip velocity condition. Design/methodology/approach Similarity transformation is used to reduce the system of partial differential equations into a system of nonlinear ordinary differential equations. The resulting equations are then solved numerically using “bvp4c” function in MATLAB software. Findings Dual solutions are found for a certain range of the unsteady, suction and stretching/shrinking parameters. Stability analysis is performed, and it is revealed that the first (upper branch) solution is stable and physically realizable, whereas the second (lower branch) solution is unstable. Practical implications The results obtained can be used to explain the characteristics and applications of the generalized slip in boundary layer flow. Such condition is applied for particulate fluids such as foams, emulsions, polymer solutions and suspensions. Furthermore, the phenomenon of stretching/shrinking sheet can be found on the manufacturing of polymer sheets, rising and shrinking balloon or moving and shrinking polymer film. Originality/value The present numerical results are original and new for the study of unsteady flow and heat transfer over a permeable stretching/shrinking sheet with generalized slip velocity.

Decision-making method for evaluating solar desalination options: the case of Saudi Arabia

2019 ◽  
Vol 11 (3) ◽  
pp. 343-356
Author(s):  
Sa'd Shannak ◽  
Malak Alnory
Keyword(s):  
Saudi Arabia ◽  
Solar Energy ◽  
Water Desalination ◽  
Economies Of Scope ◽  
Base Case ◽  
Analysis Model ◽  
Content Type ◽  
Desalination Plants ◽  
The Impact ◽  
Solar Generation

Purpose Solar as an energy source has a massive potential to reduce dependence on fossil fuels in Gulf Countries (GC). One attractive application of solar energy is solar-powered desalination, which is a viable method to produce fresh water. The most significant factor determining the potential deployment of this application is economics. Design/methodology/approach In this study, the classical economic analysis model has been modified to assess the penetration of solar technology to power desalination plants at different periods during the project lifetime. Furthermore, the environmental and financial values were combined to assess the incentive of powering desalination plants with solar energy in Saudi Arabia. Three systems of solar technologies accompanied with water desalination based on technical applicability were modeled and economically analyzed to understand the impact of various design and operation parameters. Findings This study shows that PV-RO is currently more competitive at both market and administrated prices in Saudi Arabia, followed by the MED-CSP system and finally CSP-RO system. CSP-RO system starts to generate positive surplus after 11 years, while the base case shows no positive surplus at all during the entire lifetime. Moreover, the same trend continues to hold with MED-CSP and PV-RO systems. The MED-CSP generates positive surplus after six years and PV-RO after five years only. On average, it takes eight years for a project running based on solar (CAPEX and OPEX) and desalination OPEX to generate positive cash surplus. Originality/value This paper discusses the debate about incentives for renewable energy in GC and the impact of coupling water production and solar generation. Given that there is no analytical framework built earlier, this paper provides an alternative methodology for policy analysis to understand the role of economies of scope to incentivize solar generation. In other words, the authors are investigating options to reduce the total cost of solar production as a result of increasing the number of different goods produced.

Boundary layer flow of a dusty fluid over a permeable shrinking surface

2017 ◽  
Vol 27 (4) ◽  
pp. 758-772 ◽  
Author(s):  
Rohana Abdul Hamid ◽  
Roslinda Nazar ◽  
Ioan Pop
Keyword(s):  
Boundary Layer ◽  
Particle Interaction ◽  
Engine Oil ◽  
Shrinking Sheet ◽  
Suction Parameter ◽  
Content Type ◽  
Dusty Fluid ◽  
Boundary Layer Problem ◽  
Shrinking Surface ◽  
Layer Problem

Purpose The purpose of this paper is to numerically study the boundary layer problem for the case of two-dimensional flow of dusty fluid over a shrinking surface in the presence of the fluid suction at the surface. Design/methodology/approach The governing equations of the problem are reduced to the system of ordinary differential equations using the similarity transformation and then solved using the bvp4c method in the Matlab software. Findings The effects of the drag coefficient parameter L, the fluid–particle interaction parameter δ, the suction parameter s and the particle loading parameter ω on the flow of the permeable shrinking sheet are investigated. It is found that the aforementioned parameters have different effects in the shrinking sheet flow. This study has also succeeded in discovering the second solution, and through the stability analysis, it is suggested that the solution is unstable and not physically realizable in practice. Practical implications The current findings add to a growing body of literature on the boundary layer problem in the dusty fluid. The dusty fluid is significant in various practical applications such as in the transporting suspended powdered materials through pipes, propulsion and combustion in rockets, the flow of blood in arteries, wastewater treatment and as corrosive particles in engine oil flow. Originality/value Even though the dusty fluid problem has been extensively studied in the flow of the stretching sheet, limited findings can be found over a shrinking flow. In fact, this is the first study to discover the second solution in the dusty fluid problem.

Numerical solutions for unsteady boundary layer flow of a dusty fluid past a permeable stretching/shrinking surface with particulate viscous effect

2018 ◽  
Vol 28 (6) ◽  
pp. 1374-1391 ◽  
Author(s):  
Rohana Abdul Hamid ◽  
Roslinda Nazar ◽  
Ioan Pop
Keyword(s):  
Stability Analysis ◽  
Differential Equations ◽  
Unsteady Flow ◽  
Fluid Particle ◽  
Dust Particles ◽  
Physical Parameters ◽  
Suction Parameter ◽  
Content Type ◽  
Dusty Fluid ◽  
Wide Range

Purpose This present aims to present the numerical study of the unsteady stretching/shrinking flow of a fluid-particle suspension in the presence of the constant suction and dust particle slip on the surface. Design/methodology/approach The governing partial differential equations for the two phases flows of the fluid and the dust particles are reduced to the pertinent ordinary differential equations using a similarity transformation. The numerical results are obtained using the bvp4c function in the Matlab software. Findings The results revealed that in the decelerating shrinking flow, the wall skin friction is higher in the dusty fluid when compared to the clean fluid. In addition, the effect of the fluid-particle interaction parameter to the fluid-phase can be seen more clearly in the shrinking flow. Other non-dimensional physical parameters such as the unsteadiness parameter, the mass suction parameter, the viscosity ratio parameter, the particle slip parameter and the particle loading parameter are also considered and presented in figures. Further, the second solution is discovered in this problem and the solution expanded with higher unsteadiness and suction values. Hence, the stability analysis is performed, and it is confirmed that the second solution is unstable. Practical implications In practice, the flow conditions are commonly varying with time; thus, the study of the unsteady flow is very crucial and useful. The problem of unsteady flow of a dusty fluid has a wide range of possible applications such as in the centrifugal separation of particles, sedimentation and underground disposable of radioactive waste materials. Originality/value Even though the problem of dusty fluid has been broadly investigated, limited discoveries can be found over an unsteady shrinking flow. Indeed, this paper managed to obtain the second (dual) solutions, and stability analysis is performed. Furthermore, the authors also considered the artificial particle-phase viscosity, which is an important term to study the particle-particle and particle-wall interactions. With the addition of this term, the effects of the particle slip and suction parameters can be investigated. Very few studies in the dusty fluid embedded this parameter in their problems.

Numerical investigation on activation energy of chemically reactive heat transfer unsteady flow with multiple slips

2020 ◽  
Vol 30 (11) ◽  
pp. 4955-4977
Author(s):  
Aaqib Majeed ◽  
Noorul Amin ◽  
A. Zeeshan ◽  
R. Ellahi ◽  
Sadiq M. Sait ◽  
...  
Keyword(s):  
Activation Energy ◽  
Unsteady Flow ◽  
Chemical Reaction ◽  
Magnetic Element ◽  
Content Type ◽  
Thermal Buoyancy ◽  
Matlab Package ◽  
Energy And Momentum ◽  
Hydrodynamic Effects ◽  
The Impact

Purpose The purpose of this study is to examine the impact of activation energy with binary chemical reaction for unsteady flow on permeable stretching surface. Design/methodology/approach The simultaneous effects of multiple slip and magneto-hydrodynamic effects at the boundary are taken into account. The thermal buoyancy parameter and thermal radiation are included in both energy and momentum equations, while expression of activation energy is considered in concentration equation. Three-stage Lobatto IIIa finite difference collocation technique with bvp4c MATLAB package is used to obtained numerical results. Findings The influence of key elements (Schmidt number, buoyancy force ratio factor, factor of radiation, magnetic element, unsteadiness factor, suction/injection parameter, Prandtl number, activation energy, chemical reaction rate parameter, heat source and sink parameters, velocity, thermal and concentration slips, porosity parameter and temperature difference parameter) on velocity, temperature and concentration profiles are illustrated pictorially. A detailed discussion is presented to see how the graphical aspects justify the physical prospect. Originality/value In the best of author’s knowledge, this work is yet not available in existing literature.

Temperature rise characteristic of MR fluid in a multi-disc MR clutch under slip condition

2015 ◽  
Vol 67 (2) ◽  
pp. 85-92 ◽  
Author(s):  
Daoming Wang ◽  
Youfu Hou ◽  
Zuzhi Tian ◽  
Qingrui Meng
Keyword(s):  
Temperature Field ◽  
Temperature Distribution ◽  
Temperature Rise ◽  
Slip Condition ◽  
Impact Factors ◽  
Gap Size ◽  
Mr Fluid ◽  
Content Type ◽  
Heat Transfer Theory ◽  
The Impact

Purpose – This study aims to reveal the temperature rise characteristic of magnetorheological (MR) fluid in a multi-disc MR clutch under slip condition, including the temperature distribution regularity and the impact factors. Design/methodology/approach – Three-dimensional transient heat conduction equation for the MR fluid in the working gap was derived based on the heat transfer theory. Then, numerical simulation was conducted to analyze the temperature field of MR fluid. Furthermore, an experimental study was performed to explore the temperature distribution of the MR fluid in radial and circumferential directions, as well as the effects of disc groove, slip power and gap size on temperature rise characteristic of the MR fluid. Findings – The results show that temperature appears to be largest in the center of the working gap and the temperature difference increases with the slip time. However, the temperature field in a circumferential direction is basically the same, but it presents slightly lower in the groove area. The temperature of the MR fluid increases linearly with the slip time and the rise rate increases with the slip power. Moreover, the temperature rise value decreases with the increase of gap size. Originality/value – In this paper, the temperature gradients, both in radial and circumferential directions, are experimentally measured going beyond the estimation by computer simulations. In addition, the factors that influence the temperature rise characteristic of MR fluid were fully analyzed. The results could provide a reliable basis for the development of cooling technology for high-power MR devices.

scholarly journals MHD Flow and Heat Transfer of a Jeffrey Fluid over a Porous Stretching/Shrinking Sheet with a Convective Boundary Condition

2021 ◽  
Vol 39 (3) ◽  
pp. 885-894
Author(s):  
Dondu Harish Babu ◽  
Nainaru Tarakaramu ◽  
Panyam Venkata Satya Narayana ◽  
Ganganapalli Sarojamma ◽  
Oluwole Daniel Makinde
Keyword(s):  
Heat Transfer ◽  
Flow Characteristics ◽  
Mhd Flow ◽  
Jeffrey Fluid ◽  
Shrinking Sheet ◽  
Physical Parameters ◽  
Dimensionless Numbers ◽  
Convective Boundary ◽  
Suction Parameter ◽  
The Impact

This work explores the heat transfer flow characteristics of an incompressible non-Newtonian Jeffrey fluid over a stretching/shrinking surface with thermal radiation and heat source. The sheet is linearly stretched in the presence of a transverse magnetic field with convective boundary conditions. Appropriate similarity variables are used to transform the basic governing equations (PDEs) into ODEs. The resulting equations are solved by utilizing MATLAB bvp4c. The impact of distinctive physical parameters and dimensionless numbers on the flow field and heat transfer is analysed graphically. It is noticed that the measure of heat raised with increasing the Biot number and opposite effect with the rise of the suction parameter.

Regulatory changes and the volatility of stock returns – the German solar energy sector

2014 ◽  
Vol 8 (2) ◽  
pp. 160-177 ◽  
Author(s):  
Dirk Schiereck ◽  
Julian Trillig
Keyword(s):  
Solar Energy ◽  
Stock Returns ◽  
Risk Premium ◽  
Political Risk ◽  
Energy Sector ◽  
Political Support ◽  
High Tech ◽  
Content Type ◽  
Political News ◽  
The Impact

Purpose – The purpose of this paper is to determine the impact of political risk on the German solar energy industry. The authors analyze the period from 2006 to mid-2011, when the technological development of this sector was remarkable while the whole industry is depending on political support and subsidies. Design/methodology/approach – The authors apply an EGARCH model assessing potential changes in conditional volatility response of solar industry stock returns following political risk events. Findings – The results document major changes in political support of the solar industry drive capital market risk. Whereby favorable political news significantly decrease volatility response and unfavorable political news do not affect volatility response. Moreover, the authors find that the volatility response varies with the exposure to political risk. Companies with higher exposure to political risk show more significant volatility response. Practical implications – Political risk affects the cost of capital of companies in this sector. Thus, managers are able to time equity measures in a way that they can determine periods when the investor's required return is low due to a reduced risk premium. The authors suggest risk reducing public policy facilitates investments in those industries and thus fosters the development and diffusion of immature technologies. Originality/value – The paper helps policy makers, managers, and investors to assess the impact of political risk on the overall risk of the German solar energy sector and in a broader view of immature or high-tech industries that depend crucially on governmental support.

Calendering analysis of non-isothermal viscous nanofluid containing Cu-water nanoparticles using two co-rotating rolls

2020 ◽  
pp. 875608792095161
Author(s):  
Zaheer Abbas ◽  
Sabeeh Khaliq
Keyword(s):  
Temperature Distribution ◽  
Pressure Gradient ◽  
Dynamic Viscosity ◽  
Volume Fraction ◽  
Fluid Velocity ◽  
Power Input ◽  
Physical Parameters ◽  
Nanoparticle Volume Fraction ◽  
Flow Equations ◽  
The Impact

This study is a non-isothermal analysis of the calendering process using a water based nanofluid with Cu-nanoparticles. The basic flow equations are simplified under the lubrication approximation theory (LAT) and non-dimensionalized. Theoretical velocity and pressure gradient solutions are achieved, and temperature distribution is numerically computed by finite difference method. The impact of nanoparticle volume fraction on pressure distribution, fluid velocity, temperature distribution, power input, and separating force are presented through graphs and discussed. Nanoparticle volume fraction enhances the magnitude of pressure, pressure gradient, and temperature distribution. Power input and roll-separating force also rise for higher nanoparticle volume fraction. Model II of dynamic viscosity of nanofluid has a greater impact on physical parameters as compared to the model I of dynamic viscosity.

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