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1 – 10 of 44Cornelius Bode, Wolf-Rüdiger Canders and Markus Henke
The purpose of this paper is to calculate slotting-based eddy currents in permanent magnet excited synchronous machine (PMSM) taking into account axial and circumferential…
Abstract
Purpose
The purpose of this paper is to calculate slotting-based eddy currents in permanent magnet excited synchronous machine (PMSM) taking into account axial and circumferential segmentation of magnets.
Design/methodology/approach
An analytical approach to calculate eddy current losses in PM caused by slotting harmonics of PMSM is presented. The eddy current reaction field is taken into account as well as axial and circumferential segmentation of the magnets.
Findings
The analytical model provides results comparable to 3D-FEM calculations even at high frequencies at reduced computation costs. To generalize the results the magnetic Reynold’s number is introduced.
Originality/value
Taking into account the axial and circumferential segmentation in the PDE; the approach is much more accurate compared to known approaches; accuracy is comparable to 3D-FEA.
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Chandan Kumawat, Bhupendra Kumar Sharma, Taseer Muhammad and Liaqat Ali
The purpose of this study is to determine the impact of two-phase power law nanofluid on a curved arterial blood flow under the presence of ovelapped stenosis. Over the past…
Abstract
Purpose
The purpose of this study is to determine the impact of two-phase power law nanofluid on a curved arterial blood flow under the presence of ovelapped stenosis. Over the past couple of decades, the percentage of deaths associated with blood vessel diseases has risen sharply to nearly one third of all fatalities. For vascular disease to be stopped in its tracks, it is essential to understand the vascular geometry and blood flow within the artery. In recent scenarios, because of higher thermal properties and the ability to move across stenosis and tumor cells, nanoparticles are becoming a more common and effective approach in treating cardiovascular diseases and cancer cells.
Design/methodology/approach
The present mathematical study investigates the blood flow behavior in the overlapped stenosed curved artery with cylinder shape catheter. The induced magnetic field and entropy generation for blood flow in the presence of a heat source, magnetic field and nanoparticle (Fe3O4) have been analyzed numerically. Blood is considered in artery as two-phases: core and plasma region. Power-law fluid has been considered for core region fluid, whereas Newtonian fluid is considered in the plasma region. Strongly implicit Stone’s method has been considered to solve the system of nonlinear partial differential equations (PDE’s) with 10–6 tolerance error.
Findings
The influence of various parameters has been discussed graphically. This study concludes that arterial curvature increases the probability of atherosclerosis deposition, while using an external heating source flow temperature and entropy production. In addition, if the thermal treatment procedure is carried out inside a magnetic field, it will aid in controlling blood flow velocity.
Originality/value
The findings of this computational analysis hold great significance for clinical researchers and biologists, as they offer the ability to anticipate the occurrence of endothelial cell injury and plaque accumulation in curved arteries with specific wall shear stress patterns. Consequently, these insights may contribute to the potential alleviation of the severity of these illnesses. Furthermore, the application of nanoparticles and external heat sources in the discipline of blood circulation has potential in the medically healing of illness conditions such as stenosis, cancer cells and muscular discomfort through the usage of beneficial effects.
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Jitendra Kumar Singh and Srinivasa C.T.
The purpose of this paper is to deal with an unsteady natural convection flow of a rotating fluid past an exponential accelerated vertical plate. The effect of Hall current…
Abstract
Purpose
The purpose of this paper is to deal with an unsteady natural convection flow of a rotating fluid past an exponential accelerated vertical plate. The effect of Hall current, ion-slip and magnetic field is considered. Two types of plate temperature, namely, uniform and ramped temperature are considered to model heat transfer analysis.
Design/methodology/approach
The Laplace transform technique is employed to find the closed form solutions for velocity, temperature and concentration.
Findings
The effects of flow governing parameters on the velocity profile, temperature profile, concentration profile, skin friction, Nusselt and Sherwood numbers are discussed and presented through graphs and tables. It is found that fluid velocity in the primary flow direction decreases with the increase in the magnetic parameter.
Originality/value
First time in the literature, the authors obtained closed form solution to natural convection flow of a rotating fluid past an exponential accelerated vertical plate.
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Sharmili Das, Rohit Siddharth Dhabarde and V. R. K. Raju
The purpose of this study is to develop a novel rectangular linear induction motor as an electromagnetic stirrer (EMS) using analytical followed by a numerical approach. The…
Abstract
Purpose
The purpose of this study is to develop a novel rectangular linear induction motor as an electromagnetic stirrer (EMS) using analytical followed by a numerical approach. The rectangular linear electromagnetic stirrer (RLEMS) is mainly developed for rectangular slab and billet as the end product.
Design/methodology/approach
A two-dimensional analytical approach for evaluating flux density distribution within the mold is established for RLEMS structure. Subsequently, the average stirring force within the mold is estimated from those field variables. The paper presents an analytical and numerical model for calculating the stirring force and counters the end and edge effects of linear-type EMS. Magnetic field and force profile within the mold due to polyphase rectangular stator distribution has been done with the help of Maxwell’s equation with appropriate boundary conditions by using Fourier transform and inverse Fourier transform. Subsequently, a numerical study has been carried out using a coupled thermal and electromagnetic model.
Findings
The present study investigates the physical phenomena during the solidification process because of an induced electromagnetic field and is able to extract all the electromagnetic field variables under different operating conditions, and, subsequently, provides an insight into the actual happening within the mold.
Originality/value
It provides the analytical method for solving the stirring force of the proposed new RLEMS structure by addressing the smooth and efficient variation of field and velocity profile near the corner of the mold and improves the quality of end product.
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M. Mustafa, Ammar Mushtaq, T. Hayat and A. Alsaedi
The purpose of this paper is to investigate non-linear radiation heat transfer problem for stagnation-point flow of non-Newtonian fluid obeying the power-law model. Power-law…
Abstract
Purpose
The purpose of this paper is to investigate non-linear radiation heat transfer problem for stagnation-point flow of non-Newtonian fluid obeying the power-law model. Power-law fluids of both shear-thinning and shear-thickening nature have been considered.
Design/methodology/approach
Boundary layer equations are non-dimensionalized and then solved for the numerical solutions by fourth-fifth order Runge-Kutta integration based shooting technique.
Findings
The results reveal an existence of point of inflection for the temperature distribution for sufficiently large wall to ambient temperature ratio. Moreover temperature increases and heat transfer from the plate decreases with an increase in the radiation parameter. Heat transfer rate at the sheet is bigger in dilatant (shear-thickening) fluids when compared with the pseudoplastic (shear-thinning) fluids.
Originality/value
Different from the linear radiation heat transfer problem (which can be simply reduced to rescaling of Prandtl number by a factor containing the radiation parameter), here the energy equation is strongly non-linear and it involves an additional temperature ratio parameter w =T w /T ∞. This parameter allows studying the thermal characteristics for small/large temperature differences in the flow.
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Cédric Gervais Njingang Ketchate, Oluwole Daniel Makinde, Pascalin Tiam Kapen and Didier Fokwa
This paper aims to investigate the hydrodynamic instability properties of a mixed convection flow of nanofluid in a porous channel.
Abstract
Purpose
This paper aims to investigate the hydrodynamic instability properties of a mixed convection flow of nanofluid in a porous channel.
Design/methodology/approach
The treated single-phase nanofluid is a suspension consisting of water as the working fluid and alumina as a nanoparticle. The anisotropy of the porous medium and the effects of the inclination of the magnetic field are highlighted. The effects of viscous dissipation and thermal radiation are incorporated into the energy equation. The eigenvalue equation system resulting from the stability analysis is processed numerically by the spectral collocation method.
Findings
Analysis of the results in terms of growth rate reveals that increasing the volume fraction of nanoparticles increases the critical Reynolds number. Parameters such as the mechanical anisotropy parameter and Richardson number have a destabilizing effect. The Hartmann number, permeability parameter, magnetic field inclination, Prandtl number, wave number and thermal radiation parameter showed a stabilizing effect. The Eckert number has a negligible effect on the growth rate of the disturbances.
Originality/value
Linear stability analysis of Magnetohydrodynamics (MHD) mixed convection flow of a radiating nanofluid in porous channel in presence of viscous dissipation.
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Neminath Bhujappa Naduvinamani and Mareppa Rajashekar
The purpose of this article is to analyse the effects of surface roughness on the magneto-hydrodynamic (MHD) squeeze-film characteristics between a sphere and a porous plane…
Abstract
Purpose
The purpose of this article is to analyse the effects of surface roughness on the magneto-hydrodynamic (MHD) squeeze-film characteristics between a sphere and a porous plane surface, which have not been studied so far.
Design/methodology/approach
The analytical model takes into account the effect of porosity by assuming that the flow in the porous matrix obeys modified Darcy's law. The stochastic MHD Reynold's type equation is derived by using the Christensen's stochastic method developed for hydrodynamic lubrication of rough surfaces. Two types of one-dimensional surface roughness (radial and azimuthal) patterns are considered.
Findings
The expressions for the mean MHD squeeze-film pressure and mean load-carrying capacity are obtained numerically. The results are shown graphically for selected representative parametric values. It is found that the response time increases significantly for the MHD case as compared to the corresponding non-conducting lubricants. The effect of roughness parameter is to increase/decrease the load-carrying capacity and the response time for azimuthal/radial roughness patterns as compared to the smooth case. Also, the effect of porous parameter is to decrease the load-carrying capacity and response time as compared to the solid case.
Originality/value
In this paper, an attempt has been made to analyse the combined effects of surface roughness and permeability on the MHD squeeze-film characteristics between a sphere and a plane surface.
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Bhupendra Kumar Sharma, Umesh Khanduri, Rishu Gandhi and Taseer Muhammad
The purpose of this paper is to study haemodynamic flow characteristics and entropy analysis in a bifurcated artery system subjected to stenosis, magnetohydrodynamic (MHD) flow…
Abstract
Purpose
The purpose of this paper is to study haemodynamic flow characteristics and entropy analysis in a bifurcated artery system subjected to stenosis, magnetohydrodynamic (MHD) flow and aneurysm conditions. The findings of this study offer significant insights into the intricate interplay encompassing electro-osmosis, MHD flow, microorganisms, Joule heating and the ternary hybrid nanofluid.
Design/methodology/approach
The governing equations are first non-dimensionalised, and subsequently, a coordinate transformation is used to regularise the irregular boundaries. The discretisation of the governing equations is accomplished by using the Crank–Nicolson scheme. Furthermore, the tri-diagonal matrix algorithm is applied to solve the resulting matrix arising from the discretisation.
Findings
The investigation reveals that the velocity profile experiences enhancement with an increase in the Debye–Hückel parameter, whereas the magnetic field parameter exhibits the opposite effect, reducing the velocity profile. A comparative study demonstrates the velocity distribution in Au-CuO hybrid nanofluid and Au-CuO-GO ternary hybrid nanofluid. The results indicate a notable enhancement in velocity for the ternary hybrid nanofluid compared to the hybrid nanofluids. Moreover, an increase in the Brinkmann number results in an augmentation in entropy generation.
Originality/value
This study investigates the flow characteristics and entropy analysis in a bifurcated artery system subjected to stenosis, MHD flow and aneurysm conditions. The governing equations are non-dimensionalised, and a coordinate transformation is applied to regularise the irregular boundaries. The Crank–Nicolson scheme is used to model blood flow in the presence of a ternary hybrid nanofluid (Au-CuO-GO/blood) within the arterial domain. The findings shed light on the complex interactions involving stenosis, MHD flow, aneurysms, Joule heating and the ternary hybrid nanofluid. The results indicate a decrease in the wall shear stress (WSS) profile with increasing stenosis size. The MHD effects are observed to influence the velocity distribution, as the velocity profile exhibits a declining nature with an increase in the Hartmann number. In addition, entropy generation increases with an enhancement in the Brinkmann number. This research contributes to understanding fluid dynamics and heat transfer mechanisms in bifurcated arteries, providing valuable insights for diagnosing and treating cardiovascular diseases.
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Noreen Sher Akbar and Sohail Nadeem
The purpose of this paper is to study the effects of temperature‐dependent viscosity on the peristaltic flow of Jeffrey fluid through the gap between two coaxial horizontal tubes.
Abstract
Purpose
The purpose of this paper is to study the effects of temperature‐dependent viscosity on the peristaltic flow of Jeffrey fluid through the gap between two coaxial horizontal tubes.
Design/methodology/approach
The inner tube is maintained at a temperature T00 and the outer tube has sinusoidal wave travelling down its wall and it is exposed to temperature T1. The governing problem is simplified using longwave length and low Reynold number approximations. Regular perturbation in terms of small viscosity parameter is used to obtain the expressions for the temperature and velocity for Reynold' s models of viscosity. The numerical solution of the problem has also been computed by shooting method and an agreement of numerical solutions and analytical solutions had been presented. The expressions for pressure rise and friction force are calculated numerically.
Findings
Graphical results and trapping phenomenon are presented at the end of the paper to see the physical behaviour of different parameters.
Originality/value
The paper is a new and original work on the subject of peristaltic flows and heat transfer in Jeffrey fluid.
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M. Kothandapani and V. Pushparaj
This paper aims to investigate the consequence of the combined impacts of an induced magnetic field and thermal radiation on peristaltic transport of a Carreau nanofluid in a…
Abstract
Purpose
This paper aims to investigate the consequence of the combined impacts of an induced magnetic field and thermal radiation on peristaltic transport of a Carreau nanofluid in a vertical tapered asymmetric channel. The model applied for the nanofluid comprises the effects of Brownian motion and thermophoresis.
Design/methodology/approach
The governing equations have been simplified under the widespread assumption of long-wavelength and low-Reynolds number approximations. The reduced coupled nonlinear equations of momentum and magnetic force function have also been solved analytically using the regular perturbation method.
Findings
The physical features of emerging parameters have been discussed by drawing the graphs of velocity, temperature, nanoparticle concentration profile, magnetic force function, current density, heat transfer coefficient and stream function. It has been realized that the magnetic force function is increased with the increase of Hartmann number, magnetic Reynolds number and mean flow rate.
Originality/value
It may be first paper in which the effect of induced magnetic field on peristaltic flow of non-Newtonian nanofluid in a tapered asymmetric channel has been studied.
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