Lionel Pichon

3-D FEM magneto-thermal analysis in microwave ovens

A 3-D coupled electromagnetic and thermal model has been developed for analysis of microwave heating process. The electromagnetic computation is performed with 3-D edge elements. This technique leads to an accurate deterministic study of the electromagnetic field distribution in excited junctions containing lossy dielectrics. The heat conduction equation is solved with 3-D nodal elements. The temperature dependance of the electromagnetic and heat process parameters is considered in computations. Examples are provided to validate the method. >

A thermal and electromagnetic analysis in biological objects using 3D finite elements and absorbing boundary conditions

This paper deals with the analysis of open boundary thermal-electromagnetic problems in 3D. Numerical technique is used to determine the temperature distribution inside biological objects due to their exposure to microwave radiation. The electromagnetic problem is solved with 3D mixed finite elements with second order absorbing boundary condition. The heat transfer equation is discretized with 3D nodal elements. The analysis of a lossy dielectric sphere is performed to validate the numerical approach. >

Three dimensional resonant mode analysis using edge elements

A method using edge elements is presented for the computation of resonant modes in three-dimensional resonators. The main interest of edge elements for mode analysis is that all the well known spurious modes (nonphysical solutions) are automatically eliminated. Three 3-D cavity problems are presented to show the efficiency of the numerical approach. A first example (test case) is a rectangular dielectric-loaded cavity. The two other examples are microwave cavities used in atomic frequency standards: a cylindrical cavity used in hydrogen masers, and a rectangular one used in cesium beam frequency standards. Comparisons with previously published results and analytical results are performed. >

Coupled thermal-electromagnetic simulation of a microwave curing cell

The paper presents a practical electromagnetic-thermal simulation of microwave heating during curing process of polymer resin. The model is based on finite elements developed in case of axisymmetry. The finite-element formulation of the electromagnetic problem uses the magnetic field and is well suited to axial symmetry. This model allows to give new insights to understand the differences between microwave and conventional heating.

3-D Non Linear Modelling of Microwave Heating Process Using Finite Element Method

The study of the microwave heating structures has become an interest of many industries. Actually the use of these structures is rapidely growing. Thanks to the brief start-up time and internal heating due to penetration of the wave they become an attractive energy source for heating. But the design of these structures, for example microwave ovens, remains largely an empirical process: it takes a long conception time and is commercially too expensive for the designers. Many authors have been working with different numerical methods1,4 to analyse the microwave heating process.

Comparison between tangentially continuous vector finite elements for eigenvalue problems in 3D cavities

We present a performance comparison between two vector finite elements for solving Maxwells equations in 3D cavities. The finite elements are two popular tangentially continuous finite elements which have demonstrated their efficiency in electromagnetic field computation: the first order tetrahedral element (edge element) and the second order hexahedral element. The study involves the modeling of resonators of different shapes (rectangular and cylindrical cavities). For both elements, numerical accuracy is checked against the number of unknowns.