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1

Computer simulation of heat and mass transfer effects on nanofluid flow of blood through an inclined stenosed artery with hall effect

Mishra Nidhish Kumar

Acta Mechanica et Automatica

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2024

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Vol. 18, no. 1

129--138

EN

The present study deals with the analysis of heat and mass transfer for nanofluid flow of blood through an inclined stenosed artery under the influence of the Hall effect. The effects of hematocrit-dependent viscosity, Joule heating, chemical reaction and viscous dissipation are taken into account in the governing equations of the physical model. Non-dimensional differential equations are solved using the finite difference method, by taking into account the no-slip boundary condition. The effects of different thermophysical parameters on the velocity, temperature, concentration, shear stress coefficient and Nusselt and Sherwood numbers of nano-biofluids are exhaustively discussed and analysed through graphs. With an increase in stenosis height, shear stress, the Nusselt number and the Sherwood number are computed, and the impacts of each are examined for different physical parameters. To better understand the numerous phenomena that arise in the artery when nanofluid is present, the data are displayed graphically and physically described. It is observed that as the Hartman number and Hall parameter increase, the velocity drops. This is as a result of the Lorentz force that the applied magnetic field has generated. Blood flow in the arteries is resisted by the Lorentz force. This study advances the knowledge of stenosis and other defects’ non-surgical treatment options and helps reduce post-operative consequences. Moreover, ongoing research holds promise in the biomedical field, specifically in magnetic resonance angiography (MRA), an imaging method for artery examination and anomaly detection.

2

Heat transfer in Darcy-Forchheimer flow of tangent hyperbolic fluid over an inclined plate with Joule heating

Purna Chandar Rao Darapuneni, Thiagarajan Swaminathan, Srinivasa Kumar Vajha

Journal of Applied Mathematics and Computational Mechanics

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2021

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Vol. 20, nr 3

31--40

EN

Tangent hyperbolic fluid is one of the non-Newtonian fluids in which the constitutive equation is valid for low and high shear rates and used mostly in laboratory experiments and industries. The Darcy-Forchheimer flow model is substantial in the fields where the high flow rate effect is the common phenomenon, for instance, in petroleum engineering. With these things in mind, in this article, we analysed the mixed convective dissipative Darcy-Forchheimer flow of tangent hyperbolic fluid by an inclined plate with Joule heating. Flow administering equations were altered as nonlinear ODEs and then resolved using shooting strategy. Pertinent outcomes are explained through graphs. It is discovered that fluid velocity minifies with the rise in the power law index parameter and Forchheimer number. It is detected that the thermal buoyancy parameter minimizes fluid temperature, and the magnetic field parameter ameliorates the same. What’s more, we noticed that Forchheimer number minimizes the skin friction coefficient, and the heat transfer rate is minified with the larger Eckert number. Furthermore, we have verified our results with former results for the Nusselt number and noticed a satisfactory agreement.

3

Research on Distribution and Morphology of Primary Si Under the Effect of Direct Current

Li Jiayan, Njuguna Benson Kihono, Ni Ping, Wang Liang, Tan Yi

Archives of Metallurgy and Materials

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2021

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Vol. 66, iss. 2

367--372

EN

A source of pure silicon was added into an alloy refining system during a refining process with the application of a direct electric current. The effect of the temperature difference between the graphite electrodes and the alloy was decreased. The temperature increase value (ΔT) of the Al-28.51wt.%Si alloy sample caused by Joule heating was calculated by weighing the mass of primary silicon. When the current density was 5.0×105A/m2, the overall temperature increase in the alloy was about 90°C regardless of the alloy composition. Adequate silicon atoms recorded the footprint of the electric current in the alloy melt. The flow convection generated by the electric current in the melt during the solidification process resulted in the refinement of primary silicon. The Fe impurity content in alloy refining without the electric current density was 2.16 ppm. However, it decreased to 1.27 ppmw with the application of an electric current density of 5.0×105A/m2.

4

Effect of convective heat and mass conditions in magnetohydrodynamic boundary layer flow with joule heating and thermal radiation

Sharma R. P., Tinker Seema, Gireesha B. J., Nagaraja B.

International Journal of Applied Mechanics and Engineering

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2020

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Vol. 25, no. 3

103--116

EN

A free convection viscous MHD flow over a semi-infinite vertical sheet with convective heat and mass conditions has been considered. The effects of thermal radiation, chemical reaction and Joule heating on flow are also accounted. The governing nonlinear partial differential equations have been transformed into a set of highly non-linear coupled ordinary differential equations (ODEs) using appropriate similarity transformations. Numerical solutions of transformed equations are obtained by employing the 5th order Runge-Kutta Fehlberg technique followed by the shooting technique. The influences of different flow parameters on the momentum, energy and mass field are discussed and shown graphically. Results reveal that temperature and concentration profiles enhance due to increasing heat and mass Biot number parameters.

5

Scrutinization of Joule heating and viscous dissipation on MHD flow and melting heat transfer over a stretching sheet

Kumar K. G., Gireesha B. J., Manjunatha S.

International Journal of Applied Mechanics and Engineering

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2018

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Vol. 23, no. 2

429--443

EN

The present paper deals with an analysis of the combined effect of Joule heating and viscous dissipation on an MHD boundary layer flow and melting heat transfer of a micro polar fluid over a stretching surface. Governing equations of the problem are transformed into a set of coupled nonlinear ordinary differential equations by applying proper transformations and then they are solved numerically using the RKF-45 method. The method is verified by a comparison with the established results with limiting solution. The influence of the various interesting parameters on the flow and heat transfer is analyzed in detail through plotted graphs.

6

Numerical simulation of the micropolar fluid flow and heat transfer in a channel with a shrinking and a stationary wall

Ali K., Ashraf M.

Journal of Theoretical and Applied Mechanics

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2014

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Vol. 52 nr 2

557--569

EN

We present the numerical study of hydromagnetic (MHD) flow and heat transfer characte- ristics of a viscous incompressible electrically conducting micropolar fluid in a channel with one wall shrinking and the other at rest in the presence of a transverse applied magnetic field. Different from the classical shooting methodology, we employ a combination of a di- rect and an iterative method (SOR with optimal relaxation parameter) for solving the sparse systems of linear algebraic equations arising from the FD discretization of the linearized self similar nonlinear ODEs. Effects of some physical parameters on the flow and heat transfer are discussed and presented through tables and graphs. The present investigation may be beneficial to the flow and thermal control of polymeric processing.

7

Thermal analysis of excitation circuit for pulsed eddy current transducer

Chady T., Frankowski P.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 8

313--315

EN

The aim of this paper is to determine correlation between parameters of a pulse current source and temperature of an excitation coil in eddy current Printed Circuit Board (PCB) transducer. A flow of microsecond pulse current having tens of amperes amplitude is causing significant rise of a copper trace temperature. Therefore, finding a safe working range through a proper selection of amplitude, frequency and duration of the pulse current, is an important task which can prevent damage of the transducer.

PL

Celem niniejszego artykułu jest ustalenie współzależności pomiędzy parametrami impulsowego źródła prądowego a temperaturą cewki wzbudzenia wiroprądowego przetwornika wykonanego w technologii obwodów drukowanych (PCB). W obwodzie wzbudzenia podczas przepływu mikrosekundowego impulsu prądu o amplitudzie rzędu kilkudziesięciu amperów dochodzi do znaczącego wzrostu temperatury miedzianej ścieżki. Dlatego też, określenie bezpiecznego zakresu pracy poprzez odpowiedni dobór amplitudy, częstotliwości oraz czasu trwania impulsu prądu może zapobiec uszkodzeniu przetwornika.

8

Spiekanie tytanu i hydroksyapatytu metodą iskrowego spiekania plazmowego

Garbiec D., Heyduk F.

Hutnik, Wiadomości Hutnicze

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2012

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Vol. 79, nr 8

569--574

PL

W artykule omówiono metodę iskrowego spiekania plazmowego SPS (ang. Spark Plasma Sintering). Przedstawiono graficznie proces spiekania wraz ze schematem urządzenia oraz wyjaśniono mechanizm spiekania impulsami prądu stałego. Opracowano proces spiekania proszku stopu tytanu Ti6Al4V oraz proszku hydroksyapatytu (HA) wraz z 5 % dodatkiem srebra. Ocenie za pomocą mikroskopu skaningowego poddano powierzchnię uzyskanych próbek. Na podstawie badań zaproponowano parametry wytwarzania próbek przeznaczonych do badań in-vitro. Wykazano, że minimalną temperaturą przy której można uzyskać powłokę HA charakteryzującą się dobrym połączeniem z podłożem jest 750 °C.

EN

The article discusses the method of Spark Plasma Sintering. Presented graphically sintering process and SPS device diagram. Explained the mechanism of sintering DC pulses. Titanium alloy powder Ti6Al4V and hydroxyapatite powder with 5 % silver sintering process was developed. Evaluated by scanning electron microscopy were obtained surface samples. Based on the research proposed parameters for sample preparation on in-vitro. It was shown that the minimum temperature at which the HA coating can be characterized by good access to the substrate is 750 °C.

9

Nowoczesne urządzenie do iskrowego spiekania plazmowego proszków SPS HP D 25

Garbiec D., Rybak T., Heyduk F., Janczak M.

Obróbka Plastyczna Metali

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2011

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T. 22, nr 3

221-225

PL

Artykuł informuje o znajdującym się w Instytucie Obróbki Plastycznej w Poznaniu urządzeniu SPS HP D 25, do iskrowego spiekania plazmowego. Zamieszczono schemat oraz parametry techniczne zakupionego urządzenia. Omówiono technologię wytwarzania spieków oraz możliwości wykorzystania urządzenia typu SPS HP D 25. Podano przykłady materiałów wytwarzanych metodą iskrowego spiekania plazmowego na urządzeniu SPS HP D 25.

EN

Article informs about own by Metal Forming Institute in Poznan device SPS HP D 25 for spark plasma sintering. There are devices scheme and technical parameters presented. There is sintered powders manufacturing technology discussed and abilities of SPS HD D 25 application presented. There are presented examples of materials for manufacturing by device SPS HP D 25.

10

Some aspects of the glycerol Joule heating

Maczka T., Nowak-Woźny D.

Przegląd Elektrotechniczny

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2009

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R. 85, nr 6

188-190

EN

It was measured the electrical conductivity changes of glycerol, during heating process. The heating was realised by high voltage field (Joule heating) in stationary heater, without the glycerol flow. The heater electrodes (plane and parallel) were oriented horizontally. The results of performed experiment are very promising (HV heating is effective for organic medium with low conductivity). It was suggested that two different activation energy values obtained (about 0.4 eV and 0.6 eV) are associated with the jumping of OH groups inside the hydrocarbon chains and from one chain to another.

PL

Przedstawiono metodę grzania elektrodowego gliceryny w polu wysokiego napięcia o częstotliwości 50 Hz. Proces prowadzono w układzie stacjonarnym z płaskimi horyzontalnymi elektrodami. Wyniki wskazują na możliwość grzania cieczy organicznych o niskiej przewodności elektrycznej. Monitorowanie temperaturowych zmian konduktywności oraz wyznaczone na ich podstawie wartości energii aktywacji przewodnictwa, sugerują, że podczas grzania gliceryny występują dwa mechanizmy przewodnictwa związane z termiczną dysocjacja grup hydroksylowych OH (migracja w obrębie łańcucha węglowodorowego oraz "przeskoki" po łańcuchach).

11

Joule heating effects in capillary electrophoresis : designing electrophoretic microchips

Witkowski D., Łysko J., Karczemska A.

Journal of Achievements in Materials and Manufacturing Engineering

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2009

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Vol. 37, nr 2

592-597

EN

Purpose: Computer simulations are widely used for designing, which contributes to a cheaper equipment developing process. In the last years computer simulations have begun to be also applied in different instances of microfluidics, especially in microchip electrophoresis (where an electrophoresis process takes place in the microcapillaries manufactured on the surface of the small plate) which is interesting for us. However, there are no many commercial programs enabling simulations of microfluidics. The programs existing in the market are recently developed as microscale brings new possibilities but also unpredictable effects and challenging problems. The aim of this paper is to develop a mature technique helpful in designing electrophoretic microchips [1-4]. Design/methodology/approach: Temperature distributions occurring during capillary electrophoresis because of Joule heating effects will be calculated with use of the CoventorWare™ software. Findings: Computer simulations with the model of capillary, with the same geometry as the real one, are presented. Numerical simulation results are compared with the real data from the capillary electrophoresis process. Practical implications: This is the first step to create a reliable tool for designing microfluidic devices. Originality/value: This comparison shows an ability of the CoventorWare™ software to design electrophoretic microchips.

12

3D simulations of diamond microfluidic devices

Witkowski D., Obidowski D., Łysko J., Karczemska A.

Engineering of Biomaterials

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2009

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Vol. 12, no. 86

14-16

EN

The aim of this study was to optimize the diamond microfluidic device with four microchannels. The temperature distributions in electrophoretic microchips of different geometries and different materials have been analyzed by the Coventor software. Diamond microfluidic devices are very advantageous over glass or polymer microfluidic devices; they dissipate Joule heat much more efficiently because of the highest thermal conductivity coefficient of diamond.

13

3D simulations of microfluidic devices

Witkowski D, Obidowski D, Łysko J, Karczemska A

Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka

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2008

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nr 133

359--368

EN

An approach to simulations of microfluidic devices is presented. Microfludic devices of different geometries, made of diamond and glass, have been analyzed with the Coventor™ software. Temperature gradients during the chip electrophoresis process have been analyzed. Diamond microfluidic devices are very advantageous over glass (or polymer) microfluidic devices, they dissipate Joule heat much more efficiently because of the highest thermal conductivity coefficient of diamond.