Valentin Mateev

Coupled Field Modeling of Ferrofluid Heating in Tumor Tissue

This work examines the method of magnetic fluid hyperthermia for breast cancer therapy. We develop a coupled-field model of ferrofluid transport and heating in tumor tissue. The finite element method (FEM) underpins our forward 3D electromagnetic—fluid dynamics-thermal model. The model uses anatomically precise multilevel geometry of the human breast, with known electrical properties of the tissues, and known speeds of blood and liquor in the breast vessels. We demonstrate the capabilities of the developed model on a real cancer sample acquired by a surgical procedure. The electrical properties of cancer and normal tissues are directly measured for the given sample. The thermal field results are verified by infrared thermograph imaging.

Inverse source problem for thermal fields

Purpose – The purpose of this paper is to develop an inverse approach for 3D thermal sources determination.Design/methodology/approach – The developed approach is based on the Greens function for Poisons equation. Forward and inverse couple electromagnetic‐thermal field problems are formulated. Finite elements models are built and applied. Thermal field data are acquired by thermo vision camera. The thermal field sources are determined inside of the investigated inaccessible volume object using modeled and measured data with the developed approach.Findings – The presented method and implemented examples demonstrate the possibilities of the developed approach for inverse source problem solution and determination of thermal field distributions of electrical devices.Originality/value – The proposed inverse method uses the Greens function for Poisons equation for solution of thermal field problem taking into account the couple electromagnetic‐thermal problems. Proposed inverse method is very fast, accurat...

Electromagnetic Field Modelling Using FEM of the Active Part of Oil-Immersed Transformers

The electromagnetic field of the active part of oil-immersed transformers 160kVA and 630kVA has been modelled in the present paper. Finite element method and ANSYS program have been employed for the field modelling. Based on the created model, the field distribution with values of the magnetic flux density has been obtained, as well as the Joule losses have been calculated. Two variants of the model - with and without tank are studied and compared.

Thermal analysis using 3D FEM model of oil-immersed distribution transformer

The temperature distribution in the transformer interior is a significant parameter governing a transformers performance and life expectancy. In the perspective of the user, temperatures in a transformer are important to determine the amount and duration of over load it can sustain, and to estimate the effects on the life of the transformer by operation at various temperatures. This paper presents the temperature field distribution modeling of oil-immersed distribution transformer 160kVA. Finite element method and ANSYS program have been employed for 3D model development. Based on this model, the thermal field distribution with values of temperature has been obtained.

Torque transmission characteristics of a coaxial magnetic gear

Study of the characteristics of a coaxial magnetic gear with permanent magnets is carried out in this paper. A 2D FEM model has been developed. The torque transmission of the magnetic gear is analyzed at steady-state and dynamic conditions. The research is carried out by Ansys Maxwell software.

Permanent magnets for a magnetic gear

A research of the permanent magnet influence on the steady-state and the dynamic characteristics of a magnetic gear is carried out. For this purpose, a two dimensional finite element model has been developed and applied using Ansys Maxwell package. Permanent magnets such as Alnico, ferrite, SmCo and NdFeB are utilized in order to evaluate their effect on the torque transmission of a magnetic gear.

Live tissue electromagnetic properties characterization

In this paper a method for characterization of live tissue electromagnetic properties is proposed. The method combines data, acquired by experimental computer system for bio-impedance measurements, and image data obtained by infrared camera. The data from impedance analyzer and from infrared camera are collected simultaneously for a given time period. The impedance data are associated with infrared image data for electromagnetic properties determination. The method developed is applied to evaluate the electromagnetic properties of biological tissues. The proposed method is applicable for local electric properties determination in inhomogeneous samples with random form.