scholarly journals Influence of the Size and Shape of Magnetic Core on Thermal Parameters of the Inductor

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3842
Author(s):  
Kalina Detka ◽  
Krzysztof Górecki
Keyword(s):  
Thermal Model ◽  
Heat Removal ◽  
Magnetic Core ◽  
Thermal Parameters ◽  
Size And Shape ◽  
Self Heating ◽  
The Core ◽  
Different Shapes ◽  
Good Agreement

In this paper, a new thermal model of the inductor is proposed. This model takes into account self-heating in the core and in the winding, and mutual thermal couplings between the mentioned components of the inductor. The form of the elaborated thermal model is presented. In this model, the influence of power dissipated in the core and in the winding of the inductor on the efficiency of heat removal is taken into account. Correctness of the model is verified experimentally for inductors containing ferrite cores of different shapes and dimensions. The good agreement between the results of calculations and measurements is obtained. On the basis of the obtained findings, the influence of volume and the shape of the core on thermal resistances and thermal capacitances occurring in this model is discussed.

scholarly journals Compact Thermal Model of the Pulse Transformer Taking into Account Nonlinearity of Heat Transfer

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2766 ◽  
Author(s):  
Krzysztof Górecki ◽  
Kalina Detka ◽  
Krzysztof Górski
Keyword(s):  
Heat Transfer ◽  
Thermal Model ◽  
Pulse Transformer ◽  
Model Parameters ◽  
Electric Network ◽  
Self Heating ◽  
The Core ◽  
Proposed Model ◽  
Component Temperature ◽  
Good Agreement

This paper presents a compact nonlinear thermal model of pulse transformers. The proposed model takes into account differentiation in values of the temperatures of a ferromagnetic core and each winding. The model is formulated in the form of an electric network realising electrothermal analogy. It consists of current sources representing power dissipated in the core and in each of the windings, capacitors representing thermal capacitances and controlled current sources modelling the influence of dissipated power on the thermal resistances in the proposed model. Both self-heating phenomena in each component of the transformer and mutual thermal couplings between each pair of these components are taken into account. A description of the elaborated model is presented, and the process to estimate the model parameters is proposed. The proposed model was verified experimentally for different transformers. Good agreement between the calculated and measured waveforms of each component temperature of the tested pulse transformers was obtained. Differences between the results of measurements and calculations did not exceed 9% for transformers with a toroidal core and 13% for planar transformers.

scholarly journals Effect of Size and Shape on the Vibrational and Thermodynamic Properties of Nanomaterials

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
R. Kumar ◽  
G. Sharma ◽  
M. Kumar
Keyword(s):  
Experimental Data ◽  
Thermodynamic Properties ◽  
Size And Shape ◽  
Shape Dependence ◽  
Simple Theoretical Model ◽  
Model Predictions ◽  
Different Shapes ◽  
Debye Frequency ◽  
Good Agreement ◽  
Melting Entropy

A simple theoretical model is developed to study the size and shape dependence of vibrational and thermodynamic properties of nanomaterials. To show the real connection with the nanomaterials we have studied Debye temperature, Debye frequency, melting entropy, and enthalpy in different shapes, namely, spherical, nanowire, and nanofilm of -Fe, Sn, Ag, and In. The results obtained are compared with the experimental data. A good agreement between the model predictions and the experimental data supports the theory developed in the present paper.

scholarly journals Designing the Hotspots Distribution by Anisotropic Growth

Molecules ◽  
2021 ◽  
Vol 26 (1) ◽  
pp. 187
Author(s):  
Tianshun Li ◽  
Renxian Gao ◽  
Xiaolong Zhang ◽  
Yongjun Zhang
Keyword(s):  
Au Nanoparticles ◽  
Fdtd Method ◽  
Polarization Dependence ◽  
Noble Metal Nanoparticles ◽  
Oblique Angle Deposition ◽  
Matlab Simulation ◽  
Different Shapes ◽  
Plasma Enhancement ◽  
Difference Time ◽  
Good Agreement

Changing the morphology of noble metal nanoparticles and polarization dependence of nanoparticles with different morphologies is an important part of further research on surface plasma enhancement. Therefore, we used the method based on Matlab simulation to provide a simple and effective method for preparing the morphologies of Au nanoparticles with different morphologies, and prepared the structure of Au nanoparticles with good uniformity and different morphologies by oblique angle deposition (OAD) technology. The change of the surface morphology of nanoparticles from spherical to square to diamond can be effectively controlled by changing the deposition angle. The finite difference time domain (FDTD) method was used to simulate the electromagnetic fields of Au nanoparticles with different morphologies to explore the polarization dependence of nanoparticles with different shapes, which was in good agreement with Raman spectrum.

scholarly journals Measurements and Computations of Internal Temperatures of the IGBT and the Diode Situated in the Common Case

Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 210
Author(s):  
Paweł Górecki ◽  
Krzysztof Górecki
Keyword(s):  
Thermal Properties ◽  
Measurement Error ◽  
Thermal Model ◽  
Bipolar Transistor ◽  
Internal Temperature ◽  
Self Heating ◽  
Factors Influencing ◽  
Proposed Model ◽  
The Common ◽  
Transient Thermal

This article proposes effective methods of measurements and computations of internal temperature of the dies of the Insulted Gate Bipolar Transistor (IGBT) and the diode mounted in the common case. The nonlinear compact thermal model of the considered device is proposed. This model takes into account both self-heating phenomena in both dies and mutual thermal couplings between them. In the proposed model, the influence of the device internal temperature on self and transfer thermal resistances is taken into account. Methods of measurements of each self and transfer transient thermal impedances occurring in this model are described and factors influencing the measurement error of these methods are analysed. Some results illustrating thermal properties of the investigated devices including the IGBT and the antiparallel diode in the common case are shown and discussed. Computations illustrating the usefulness of the proposed compact thermal model are presented and compared to the results of measurements. It is proved that differences between internal temperature of both dies included in the TO-247 case can exceed even 15 K.

Calculation studies of coated particles performance in sodium-cooled fast reactor

Kerntechnik ◽  
2021 ◽  
Vol 86 (1) ◽  
pp. 45-49
Author(s):  
N. V. Maslov ◽  
E. I. Grishanin ◽  
P. N. Alekseev
Keyword(s):  
Fast Reactor ◽  
Reactor Core ◽  
Heat Removal ◽  
Design Solution ◽  
Fast Neutrons ◽  
Steel Shell ◽  
Primary Circuit ◽  
Coated Particles ◽  
The Core ◽  
Fuel Assemblies

Abstract This paper presents results of calculation studies of the viability of coated particles in the conditions of the reactor core on fast neutrons with sodium cooling, justifying the development of the concept of the reactor BN with microspherical fuel. Traditional rod fuel assemblies with pellet MOX fuel in the core of a fast sodium reactor are directly replaced by fuel assemblies with micro-spherical mixed (U,Pu)C-fuel. Due to the fact that the micro-spherical (U, Pu)C fuel has a developed heat removal surface and that the design solution for the fuel assembly with coated particles is horizontal cooling of the microspherical fuel, the core has additional possibilities of increasing inherent (passive) safety and improve the competitiveness of BN type of reactors. It is obvious from obtained results that the microspherical (U, Pu)C fuel is limited with the maximal burn-up depth of ∼11% of heavy atoms in conditions of the sodium-cooled fast reactor core at the conservative approach; it gives the possibility of reaching stated thermal-hydraulic and neutron-physical characteristics. Such a tolerant fuel makes it less likely that fission products will enter the primary circuit in case of accidents with loss of coolant and the introduction of positive reactivity, since the coating of microspherical fuel withstands higher temperatures than the steel shell of traditional rod-type fuel elements.

Prediction of Cavitation Inception Within Regions of Flow Separation

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Eduard Amromin
Keyword(s):  
Experimental Data ◽  
Turbulent Flow ◽  
Flow Separation ◽  
Computational Method ◽  
Average Flow ◽  
Cavitation Inception ◽  
The Core ◽  
Good Agreement

Cavitation within regions of flow separation appears in drifting vortices. A two-part computational method is employed for prediction of cavitation inception number there. The first part is an analysis of the average flow in separation regions without consideration of an impact of vortices. The second part is an analysis of equilibrium of the bubble within the core of a vortex located in the turbulent flow of known average characteristics. Computed cavitation inception numbers for axisymmetric flows are in the good agreement with the known experimental data.

CFD Investigation of Thermal-Hydraulic Behaviors in Full Reactor Core for Sodium-Cooled Fast Reactor

2018 ◽  
Author(s):  
Jing Chen ◽  
Dalin Zhang ◽  
Suizheng Qiu ◽  
Kui Zhang ◽  
Mingjun Wang ◽  
...  
Keyword(s):  
Fast Reactor ◽  
Power Distribution ◽  
Three Dimensional ◽  
Reactor Core ◽  
Heat Removal ◽  
The Core ◽  
Computational Fluid Dynamics Cfd ◽  
Heat Removal System ◽  
China Experimental Fast Reactor ◽  
Full Core

As the first developmental step of the sodium-cooled fast reactor (SFR) in China, the pool-type China Experimental Fast Reactor (CEFR) is equipped with the openings and inter-wrapper space in the core, which act as an important part of the decay heat removal system. The accurate prediction of coolant flow in the reactor core calls for complete three-dimensional calculations. In the present study, an investigation of thermal-hydraulic behaviors in a 180° full core model similar to that of CEFR was carried out using commercial Computational Fluid Dynamics (CFD) software. The actual geometries of the peripheral core baffle, fluid channels and narrow inter-wrapper gap were built up, and numerous subassemblies (SAs) were modeled as the porous medium with appropriate resistance and radial power distribution. First, the three-dimensional flow and temperature distributions in the full core under normal operating condition are obtained and quantitatively analyzed. And then the effect of inter-wrapper flow (IWF) on heat transfer performance is evaluated. In addition, the detailed flow path and direction in local inter-wrapper space including the internal and outlet regions are captured. This work can provide some valuable understanding of the core thermal-hydraulic phenomena for the research and design of SFRs.

scholarly journals Stress Concentration Studies in Flat Plates with Rectangular Cut-Outs Using Finite Element Method

2019 ◽  
Vol 4 (1) ◽  
pp. 66-76 ◽  
Author(s):  
Dheeraj Gunwant
Keyword(s):  
Infinite Plate ◽  
Geometrical Parameters ◽  
Light Weight ◽  
Flat Plates ◽  
Uniaxial Load ◽  
Desirable Feature ◽  
Different Shapes ◽  
Stress States ◽  
Analytical Relations ◽  
Good Agreement

Presence of cut-outs of different shapes is inevitable and is many times considered to be a desirable feature for the design of light-weight components. However, the presence of such cut-outs induces highly localized stresses in their vicinity which cannot be resolved using analytical relations and elementary equations of the strength of materials. In the recent years, FEM has evolved as a crucial tool for handling such problems with reduced degree of complexity. The present investigation is aimed at studying the effect of various geometrical parameters and loading scenarios on the SCF induced in an infinite plate in presence of rectangular cut-out with filleted corners. In the first step, the model was subjected to uniaxial load and the obtained values of SCF exhibited good agreement with analytical values. The model was further subjected to systematically varied stress states and geometrical parameters in order to study their effect on the SCF.

scholarly journals A Lumped Transient Thermal Model for Self-Heating in Mosfets.(Dept.M)

2021 ◽  
Vol 25 (2) ◽  
pp. 46-58
Author(s):  
Mohamed Sabry ◽  
W. Fikry ◽  
Kh. Abdel Salam ◽  
A. Nasser ◽  
Mohamed Awad
Keyword(s):  
Thermal Model ◽  
Self Heating ◽  
Transient Thermal
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