scholarly journals Optimization of Heat Transfer Process in Double Gate MOSFET Using Modified BDE Model

2021 ◽  
Author(s):  
Sami Ghedira ◽  
Faouzi Nasri ◽  
Abir Mera
Keyword(s):  
Heat Transfer ◽  
Current Density ◽  
Gate Dielectric ◽  
Thermal Characteristics ◽  
Heat Transfer Process ◽  
Electrical Model ◽  
Drift Diffusion ◽  
Proposed Model ◽  
Heat Transfer Phenomenon ◽  
D Model

Abstract In this paper, a nonlinear electrical model is derived and is used to calculate the electric field and the current density. To corroborate our electrical model, it was compared to TCAD simulator. It was shown that the proposed model captures the current density with a good degree of agreement with TCAD simulator. The electrical model is given by the modified Drift-Diffusion (D-D) model coupled with the Ballistic-Diffusive Equation (BDE) which is able to predict the heat transfer phenomenon in the nanoscale regime. The thermal device performance is then investigated by varying device parameters including gate and drain biases with implementation of different gate dielectric to explore its response on thermal characteristics. It was further shown that the proposed electro-thermal model is able to predict the nano heat conduction in (DG) nanostructure devices. In addition, it is shown that the heat flux process could be controlled by adjusting the drain and gate voltages.

scholarly journals Review on Heat Transfer Process Inside Open and Closed Porous Cavity

2020 ◽  
Vol 26 (9) ◽  
pp. 204-216
Author(s):  
Akeel Abdullah Mohammed
Keyword(s):  
Heat Transfer ◽  
Transfer Process ◽  
Convection Heat Transfer ◽  
Thermal Characteristics ◽  
Darcy Number ◽  
Heat Transfer Process ◽  
Dominant Factor ◽  
Compact Heat Exchangers ◽  
Porous Cavity ◽  
Fluid Field

Many researchers used different methods in their investigations to enhance the heat transfer coefficient, one of these methods is using porous medium. Heat transfer process inside closed and open cavities filled with a fluid-saturated porous media has a considerable importance in different engineering applications, such as compact heat exchangers, nuclear reactors and solar collectors. So, the present paper comprises a review on natural, forced, and combined convection heat transfer inside a porous cavity with and without driven lid. Most of the researchers on this specific subject studied the effect of many parameters on the heat transfer and fluid field inside a porous cavity, like the angle of inclination, the presence of vibration, magnetic fields, and heat generation. They used different thermal and hydrodynamic boundary conditions, different geometries of cavity, and different saturated-fluids. Results manifested that the fluid and thermal characteristics enhance greatly as porosity increases at a high value of Darcy number. Also, vibrational effects are a dominant factor in the heat transfer process only at high Darcy and Reynolds numbers.

scholarly journals Heat Transfer Modeling in Bone Tumour Hyperthermia Induced by Hydroxyapatite Magnetic Thermo-Seeds

2020 ◽  
Vol 14 (1) ◽  
pp. 77-89
Author(s):  
Fabio Fanari ◽  
Lorena Mariani ◽  
Francesco Desogus
Keyword(s):  
Heat Transfer ◽  
Numerical Models ◽  
Bone Tumour ◽  
Heat Transfer Process ◽  
Thermal Treatments ◽  
Hyperthermia Treatment ◽  
Theoretical Frameworks ◽  
Thermal Dynamics ◽  
Electromagnetic Power ◽  
Proposed Model

Background: Hyperthermia is an adjuvant oncologic thermal therapy. In the case of deep-seated bone cancers, the interstitial hyperthermia treatment can be performed using thermo-seeds, implanted biomaterial components that are able to convert external electromagnetic power into thermal one. Several magnetic biomaterials have been synthesized for thermal treatments of cancer. However, less attention has been paid to the modeling description of the therapy, especially when the bio-heat transfer process is coupled to the electromagnetic heating. Objective: In this work, a comparison between the available analytical and numerical models is presented. Methods: A non-linear multiphysics model is used to study and describe the performance of cylindrical magnetic hydroxyapatite thermo-seeds to treat residual cancer cells of bone tumours. Results: The thermal dynamics and treatment outcome are carefully evaluated. Under the exposure of a magnetic field of 30 mT, working at 300 kHz, it was found that magnetic hydroxyapatite implants with a size of 10 mm × 10 mm could increase the temperature above 42 °C for 60 min. Conclusion: The proposed model overcomes the limitations of the available theoretical frameworks, and the results reveal the relevancy of the implant geometry to the effectiveness of the hyperthermia treatment.

scholarly journals A non integer order, state space model for one dimensional heat transfer process

2016 ◽  
Vol 26 (2) ◽  
pp. 261-275 ◽  
Author(s):  
Krzysztof Oprzedkiewicz ◽  
Edyta Gawin
Keyword(s):  
Heat Transfer ◽  
State Space ◽  
Transfer Process ◽  
State Space Model ◽  
State Equation ◽  
Heat Transfer Process ◽  
Order Model ◽  
One Dimensional ◽  
Integer Order ◽  
Proposed Model

Abstract In the paper a new, state space, non integer order model for one dimensional heat transfer process is presented. The model is based on known semigroup model. The derivative with respect to time is described by the non integer order Caputo operator, the spatial derivative is described by integer order operator. The elementary properties of the state operator are proven. The solution of state equation is calculated with the use of Laplace transform. Results of experiments show, that the proposed model is more accurate than analogical integer order model in the sense of square cost function.

Analysis about enhancement in thermal characteristics of viscous fluid flow with induction of ferrite particles by using Cattaneo Christov theory

2021 ◽  
pp. 095440622110426
Author(s):  
Wajiha Tahir ◽  
S Bilal ◽  
Nabeela Kousar ◽  
Imtiaz Ali Shah ◽  
Ali S Alqahtani
Keyword(s):  
Heat Transfer ◽  
Temperature Profile ◽  
Zinc Ferrite ◽  
Thermal Flux ◽  
Mathematical Formulation ◽  
Thermal Characteristics ◽  
Heat Transfer Process ◽  
Vital Role ◽  
Solid Particles ◽  
Nickel Zinc

The elevated convective heat transfer process plays vital role in performance of electronic and engineering equipment’s. Over the years various attempts have been executed in this regards, including the insertion of nano elements in poorly conducting liquids. Initially, improvement in thermophysical characteristics of ordinary fluids was observed but with advancement in nanoparticles structuring new classifications in nano elements are found. Among these discoveries experimentations have explored highly fascinating and intrinsically featured class of nanomaterials renowned as ferromagnetic nano constituents. So, the motivation regarding this investigation is execution about change in thermal features of base liquid with insertion of different ferrite particles. Here, water is considered as based liquid and Nickel Zinc Ferrite (NiZnFe2O4) and magnetite ferrite (Fe2O4) as solid particles are inserted. Impact of magnetic dipole is also envisioned to produce optimized effectiveness of ferrite particles. Energy transmission in flow domain is depicted by incorporation of Cattaneo-Christov heat flux model. Mathematical formulation containing thermo mechanical features of ferrite particles are attained in complexly structured partial differential system and afterwards similarity transformations are implemented for transmutation into ODES. Constructed problem is simulated by implementing numerical approaches. Influence of involved variables on associated distributions are displayed through graphs and tables. It is demonstrated that momentum as well as heat transfer of base fluid augments with inclusion of Nickel Zinc ferrite as compared magnetite ferrite. It is inferred that velocity shows declining behavior against Curie temperature whereas reverse behavior is seen for temperature profile. It is divulged that viscous dissipation imparts diminishing impact on momentum whereas contrary behavior is depicted in case of temperature profile. In addition, increment in wall drag magnitude and thermal flux is manipulated by incorporation of (NiZnFe2O4) rather than (Fe2O4).

Thermal Characteristics of a Free Radial Liquid Jet Impinging on a Hot Surface

2001 ◽  
Author(s):  
Ahmed Hassaneen ◽  
Muhammad M. Rahman
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Nusselt Number ◽  
Transfer Process ◽  
Average Nusselt Number ◽  
Incidence Angle ◽  
Thermal Characteristics ◽  
Heat Transfer Process ◽  
Liquid Jet ◽  
Geometrical Parameters

Abstract This paper presents results of CFD computation of the heat transfer process in a radial impinging free liquid jet. The jet is impinging on a flat circular disk and the flow downstream of the impinging area spreads outward and inward on the disk. The solution is made under steady state and laminar flow conditions. The solution is obtained for the axisymmetric radial jet with two free surfaces. Different incidence angle of the jet and different flow Reynolds number (Re) were considered in the analysis. The effect of jet elevation from the disk is discussed in addition to different thickness of the hot plate. Due to lack of experimental data on this typical flow problem, the results were qualitatively compared with the available experimental data of the closest flow condition in the literature. The jet incidence angle and jet elevation were found to have strong effects on the velocity field and the free surface position of the spreading flow on the disk and consequently affected the heat transfer process. The disc thickness is also found to have a strong effect on the local and average Nusselt number. Results are documented by plotting the distribution of local and average Nusselt number versus the geometrical parameters.

Optimization of Temperature Measurement Technique Used in High Heat Flux Environment

2011 ◽  
Author(s):  
Dmitriy Romanov ◽  
Jason Devoe ◽  
Lev Ginzbursky
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Thermal Characteristics ◽  
High Heat ◽  
Temperature Sensors ◽  
Heat Transfer Process ◽  
Heat Flux Sensor ◽  
High Heat Flux ◽  
Thin Wall ◽  
Environment Temperature

The heat transfer calculations for turbine flows are known to have a substantial degree of uncertainty [1]. Therefore experimental verification of analytical predictions is needed. Properly done, metal temperature measurements could inform a designer about the existence of under-cooled or over-cooled locations, suggesting possible opportunities to improve engine thermodynamic and durability characteristics. Operating in a difficult turbine environment, temperature sensors must be well understood to be able to perform the critical task of thermal mapping accurately. The authors analyzed the influence of factors such as heat flux, sensor positioning, and thermal characteristics of installation assembly on the accuracy of the temperature measured by Crystal Temperature Sensors (CTS) and S-type Thermocouples (TC). The investigation was performed using a numerical simulation of the heat-transfer process taking place in a thin wall with the sensors installed. The recommendations drawn from this experience should help analytical designers and instrumentation engineers optimize experimental techniques and improve the quality of engine test result interpretation.

scholarly journals Fractional Order Model of the Two Dimensional Heat Transfer Process

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6371
Author(s):  
Krzysztof Oprzędkiewicz ◽  
Wojciech Mitkowski ◽  
Maciej Rosół
Keyword(s):  
Heat Transfer ◽  
Fractional Order ◽  
Heat Transfer Process ◽  
Two Dimensional ◽  
Thermal Camera ◽  
Order Model ◽  
Fractional Order Model ◽  
Proposed Model ◽  
Spectrum Decomposition ◽  
Theoretical Results

In this paper, a new, state space, fractional order model of a heat transfer in two dimensional plate is addressed. The proposed model derives directly from a two dimensional heat transfer equation. It employes the Caputo operator to express the fractional order differences along time. The spectrum decomposition and stability of the model are analysed. The formulae of impluse and step responses of the model are proved. Theoretical results are verified using experimental data from thermal camera. Comparison model vs experiment shows that the proposed fractional model is more accurate in the sense of MSE cost function than integer order model.

Design of the Blast Furnace Wall Structure Made of Efficient Materials. Part 4. Calculation Examples

2020 ◽  
Vol 786 (11) ◽  
pp. 30-34
Author(s):  
A.M. IBRAGIMOV ◽  
◽  
L.Yu. GNEDINA ◽  
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Blast Furnace ◽  
Boundary Value Problems ◽  
Transfer Process ◽  
Rational Design ◽  
Boundary Value ◽  
Heat Transfer Process ◽  
Furnace Wall ◽  
Time Interval

This work is part of a series of articles under the general title The structural design of the blast furnace wall from efficient materials [1–3]. In part 1, Problem statement and calculation prerequisites, typical multilayer enclosing structures of a blast furnace are considered. The layers that make up these structures are described. The main attention is paid to the lining layer. The process of iron smelting and temperature conditions in the characteristic layers of the internal environment of the furnace is briefly described. Based on the theory of A.V. Lykov, the initial equations describing the interrelated transfer of heat and mass in a solid are analyzed in relation to the task – an adequate description of the processes for the purpose of further rational design of the multilayer enclosing structure of the blast furnace. A priori the enclosing structure is considered from a mathematical point of view as the unlimited plate. In part 2, Solving boundary value problems of heat transfer, boundary value problems of heat transfer in individual layers of a structure with different boundary conditions are considered, their solutions, which are basic when developing a mathematical model of a non-stationary heat transfer process in a multi-layer enclosing structure, are given. Part 3 presents a mathematical model of the heat transfer process in the enclosing structure and an algorithm for its implementation. The proposed mathematical model makes it possible to solve a large number of problems. Part 4 presents a number of examples of calculating the heat transfer process in a multilayer blast furnace enclosing structure. The results obtained correlate with the results obtained by other authors, this makes it possible to conclude that the new mathematical model is suitable for solving the problem of rational design of the enclosing structure, as well as to simulate situations that occur at any time interval of operation of the blast furnace enclosure.

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