The main features of the present numerical model is to explore the behavior of an ionic transport electroviscous boundary layer flow over a rotating disk. For this purpose, the Nernst-Planck equation ...and Poisson's equation together with the traditional Navier Stokes equations are simulated for the conservation of ionic species. The Poisson-Nernst-Planck (PNP) equation neglects sterile effects and ion-ion interactions, which is widely recognized by the electro-chemists community, leading to advancement of various mathematical models. The modeled governing equations of the fluid flow are transformed to dimensionless ordinary differential equations under Von Karman's approach. The Parametric Continuation Method (PCM) is applied, in order to analyzed the numerical simulation of the problem. For validity of the method the results are compared with another numerical method (bvp4c) and some previous published work, seem to be in a very good agreement to each other. It is found that the potential gradient becomes smaller as Debye length parameter K increases and exposing more counter-ions to the flow which results an increase in the fluid velocity. The physical constraints impact on radial, axial and tangential velocity and on both positive and negative charge profile are sketched and briefly discussed.
•The Navier-Stokes, are coupled with Nernst-Planck equation describing conservation of each ion species.•The basic governing equations of the flow are solved numerically by using Parametric Continuation Method.•The flow pattern has been analyzed by the effects of natural parameters.•K the dimensionless inverse Debye length (a measure of the ratio of the disk radius R to Electric Double Layer thickness).•At small charge density fluid flows only by the intersection of electro osmosis.
Unsteady magnetohydrodynamic (MHD) flow of a second grade fluid over a stretching sheet is a focus of this steady. Surface tension is considered to be varies linearly with temperature. The stretching ...velocity is defined in (Liu and Andersson in Int. J. Therm. Sci. 47(6):766-772,
2008
). Similarity transformation reported by Abbas
et al.
(Math. Comput. Model. 48:518-526,
2008
) are used to develop nonlinear system of differential equations coupled in velocity and temperature fields. The system is solved by the homotopy-analysis method (HAM), while the effects of different parameters such as the unsteadiness parameter
S
, film thickness, Hartmann number
Ma
, Prandtl number
Pr
, Thermocapillary number
M
, heat flux
−
θ
′
(
0
)
, surface skin-friction coefficient
f
″
(
0
)
, free surface temperature
θ
(
1
)
for flow field, and heat transfer are studied in this article.
Different strategies have been utilized by investigators with the intention of upgrading the thermal characteristics of ordinary liquids like water and kerosene oil. The focus is currently on hybrid ...nanomaterials since they are more efficient than nanofluids, so as to increase the thermal conductivity of fluids and mixtures. In a similar manner, this investigation is performed with the aim of breaking down the consistent mixed convection flow close to a two-dimensional unstable flow between two squeezing plates with homogeneous and heterogeneous reaction in the presence of hybrid nanoparticles of the porous medium. A sustainable suspension in the ethylene glycol with water is set by dissolving inorganic substances, iron oxide Fe3O4 and cobalt (Co), to form Fe3O4−Co/C2H6O2−H2O hybrid nanofluid. The numerical and analytical model portraying the fluid flow has been planned, and similitude conditions have been determined with the assistance of the same transformations. The shooting technique has been used to solve nonlinear numerical solution. To check the validity of the results obtained from the shooting mode, the Matlab built-in function BVP4c and Mathematica built-in function homotopy analysis method (HAM) are used. The influence of rising parameters on velocity, temperature, skin friction factor, Nusselt number, and Sherwood number is evaluated with the help of graphs and tables. It has been found in this work that to acquire a productive thermal framework, the hybrid nanoparticles should be considered instead of a single sort of nanoparticles. In addition, the velocities of both the hybrid nanofluids and simple nanofluids are upgraded by the mixed convection boundary, whereas they are decreased by the porosity. An augmentation in volumetric fraction of nanoparticles correlates to an increment in the heat transmission rate. It is also found that heat transfer rate for Fe3O4−Co/C2H6O2−H2O hybrid nanofluids (HNF) is better than that of the Fe3O4−C2H6O2−H2O of single nanofluids (SNF). This research shows that hybrid nanofluids play a significant part in the transfer of heat and in the distribution of nanofluids at higher temperatures.
The problem of heat transfer analysis is considered in electrically conducting thin film flows with slip boundary conditions. The flow is assumed to be obeying the nonlinear rheological constitutive ...equation of a third grade fluid. We have solved the governing nonlinear equations of present problems using the traditional Adomian decomposition method (ADM). Particular attention is given to the combined effect of heat and MHD on the velocity field. The results include the profile of velocity, volume flux, skin friction, average velocity, and the temperature distribution across the film. The effects of model parameters on velocity, skin friction and temperature variation have been studied. Optimal homotopy asymptotic method (OHAM) is also used for comparison. The numerical results and absolute errors are derived in tables.
Inorganic species are released during pressurized gasification, can cause severe problem of hot corrosion. The direct utilization of coal is harmful for power plants. The aim of work to obtained ...comprehensive knowledge of release alkali species Na-,K-,Cl and S-species prior to carry out experiment. Therefore thermodynamic equilibrium calculations were performed by Fact Sage 5.2 and simulated the gasification environment at elevated pressure.Three soft Pakistani coal such as Lakhra (Vad < 41.44%), Thar (Vad < 42.02%) and Sor-range ((Vad < 21.11%) belong to Lignite and sub-bituminous coal were selected and releasing order was calculated by plotting mole fraction of each species Vs pressure (5 to 15bar ) at 1000°C.On the basis of predicted releasing order the H2S can be predicted most stable species under gasification at elevated pressure. The high released amount of SO2, H2S, NaCl, KCl and HCl was predicted for LKH and SRC at 5 and 15 bar pressure and 1000°C temperature. Comparing with high pressure the predicted released of H2S was found higher than SO2, NaCl, KCl and HCl at 15 bar pressure while the released of SO2 was observed lower than H2S, NaCl, KCl and HCl at 5 bar pressure during gasification process. The above available predicted information is valuable for hot gas cleaning technology.
An Analysis has been carried out to study the magnetohydrodynamic boundary layer flow of Carreau fluid with variable thermal conductivity and viscosity over stretching/shrinking sheet. The thermal ...conductivity and viscosity is considered to be vary linearly with temperature. By applying suitable similarity transformations, the constitutive equation of Carreau fluid along with energy and transport equations transformed to set of ordinary differential equations. The obtained problem is solved analytically by Homotopy Analysis Method (HAM). As increasing magnetic force, skin friction and heat transfer rate are decreased in the stretching case, while opposite effects are seem in the shrinking case. Similarly, increase in the Lewis number leads to a reduction in the concentration profile. furthermore, increasing the power index and the Weissenberg number leads to an increase in skin friction and a heat transfer rate in the case of stretching, while both are reduced in case of shrinking For validity purpose the problem is also solved numerically using BVP4C (Matlab routine). Analysis of results show that analytical and numerical solutions are in excellent agreement. Furthermore, the impacts of different fluid parameters such as the Weissenberg number We2, Magnetic parameter M2, Suction parameter s, Prandtl number Pr, Lewis number Le, Stretching/ Shrinking parameter B and the heat flux constants on the velocity, temperature and concentration profiles are investigated graphically.
•MHD boundary layer Carreau fluid flow with thermal conductivity/viscosity over a stretching/ shrinking sheet is investigated.•A suitable transformation has been used to transform the governing equation into a set of ordinary differential equations.•Numerical and analytical solutions have been compared for the validity of current model.•Effects of the parameters on velocity, temperature and concentration profiles have been investigated graphically.
This work considers two-phase flow of an elastic-viscous fluid for double-layer coating of wire. The wet-on-wet (WOW) coating process is used in this study. The analytical solution of the theoretical ...model is obtained by Optimal Homotopy Asymptotic Method (OHAM). The expression for the velocity field and temperature distribution for both layers is obtained. The convergence of the obtained series solution is established. The analytical results are verified by Adomian Decomposition Method (ADM). The obtained velocity field is compared with the existing exact solution of the same flow problem of second-grade fluid and with analytical solution of a third-grade fluid. Also, emerging parameters on the solutions are discussed and appropriate conclusions are drawn.
In this investigation, the work of Noor and Hashim (2010) is explored in a more advance form by considering the effectiveness of the second grade boundary layer equations with the adjust of pressure ...term in the presence of transverse magnetic field. The conducted unsteady momentum equations in xy-plane attached with energy equation are shifted into a group of two ODEs involving the important physical parameters, having effective results for the constructive progress. These parameters are second grade non-dimensional parameter, surface tension parameter(thermocapillary number), temperature Grashof number, sheet thickness, magnetic parameter(Hartmann number), Prandtl number and non-dimensional parameter of unsteadiness. The same system give local free surface temperature, heat transfer(heat flux) normal to the flow surface and local surface skin friction. All observations are possible by the use of Homotopy Analysis Method called HAM. Graphs and Tables are made to see the physical properties of the fluid flow by varying arbitrary parameters. Error analysis is a part of this study which define the validity of the HAM method. Further, comparison of the methods(HAM and BVP4C) are done in a table for the validity of the solution.
Modern optical fibers require a double-layer coating on the glass fiber in order to provide protection from signal attenuation and mechanical damage. The most important plastic resins used in wires ...and optical fibers are plastic polyvinyl chloride (PVC) and low and high density polyethylene (LDPE/HDPE), nylon and Polysulfone. One of the most important things which affect the final product after processing is the design of the coating die. In the present study, double-layer optical fiber coating is performed using melt polymer satisfying Oldroyd 8-constant fluid model in a pressure type die with the effect of magneto-hydrodynamic (MHD). Wet-on-wet coating process is applied for double-layer optical fiber coating. The coating process in the coating die is modeled as a simple two-layer Couette flow of two immiscible fluids in an annulus with an assigned pressure gradient. Based on the assumptions of fully developed laminar and MHD flow, the Oldroyd 8-constant model of non-Newtonian fluid of two immiscible resin layers is modeled. The governing nonlinear equations are solved analytically by the new technique of Optimal Homotopy Asymptotic Method (OHAM). The convergence of the series solution is established. The results are also verified by the Adomian Decomposition Method (ADM). The effect of important parameters such as magnetic parameter Mi, the dilatant constant α, the Pseodoplastic constant β, the radii ratio δ, the pressure gradient Ω, the speed of fiber optics V, and the viscosity ratio κ on the velocity profiles, thickness of coated fiber optics, volume flow rate, and shear stress on the fiber optics are investigated. At the end the result of the present work is also compared with the experimental results already available in the literature by taking non-Newtonian parameters tends to zero.
BackgroundScreening for neonatal hyperbilirubinaemia in the postnatal ward has traditionally been performed using serum bilirubin sampling, but this has significant drawbacks such as risk of ...infection and slower reporting time.ObjectiveWe aimed to assess the impact of introducing transcutaneous bilirubin (TcBR) testing using TcBR nomogram on the number of serum bilirubin samples sent.MethodsA before-and-after study was performed following the introduction of a protocol integrating the use of the Dragger JM-105 transcutaneous bilirubinometer in the postnatal ward. Only babies born at ≥37 weeks of gestation, weighing ≥2500 g who presented with jaundice after the first 24 hours and within the first 7 days of life were included in the study. The number of total serum bilirubin samples (TSBRs) sent were compared for the 6-month periods before and after (a total of 12 months) implementation of the new protocol.ResultsIn the pre-implementation phase, a total of 882 (49%) out of 1815 babies had at least one serum bilirubin sample taken as opposed to a total of 236 (17%) out of 1394 babies in the post-implementation phase. The odds of performing TSBRs at least one time among babies in post-implementation phase were 79% lower than in pre-implementation phase (OR 0.21, 95% CI 0.18 to 0.25). We also estimated a significant cost saving of approximately US$1800 over a period of 6 monthsConclusionTcBR testing used in conjunction with our proposed nomogram significantly reduces the need for serum bilirubin sampling.
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