Software design of optimization laboratory OptiLab

An overview of the software design, methods and data abstraction of the OptiLab framework is presented. The framework is aimed at the advanced analysis and optimization of mathematical models of physical fields and also coupled problems. The algorithms of the framework are implemented with respect to solution demands and huge data requirements. The paper presents a short description of the framework, its basic concept and structure

Induction heating of rotating nonmagnetic billet in magnetic field produced by high-parameter permanent magnets

An advanced way of induction heating of nonmagnetic billets is discussed and modeled. The billet rotates in a stationary magnetic field produced by unmoving high-parameter permanent magnets fixed on magnetic circuit of an appropriate shape. The mathematical model of the problem consisting of two coupled partial differential equations is solved numerically, in the monolithic formulation. Computations are carried out using our own code Agros2D based on a fully adaptive higher-order finite element method. The most important resultsare verified experimentally on our own laboratory device

Integral computation of magnetic field of shielded three-phase line

The paper deals with numerical modeling of a three-phase harmonic-current carrying shielded line. In most similar cases, computation of magnetic field and other associated quantities is realized using the finite element method that is effective, reliable and the results obtained correspond to the physical reality. Nevertheless, the method may become problematic when particular subregions (conductors, insulation, shielding elements) are geometrically incommensurable, which is even the case of thin shielding shells. That is why the authors use the integral approach for modeling of the relevant effects. Presented is its basic continuous mathematical model that is solved numerically. The theoretical analysis is supplemented with a typical example

Separation of Plastic Particles in Electrostatic Field Produced by Electrodes of Optimized Shape

Shape optimization of electrodes for the device for electrostatic separation of triboelectrically charged plastic particles is carried out. The objective function maximizes the efficiency of separation consisting in the highest possible number of particles falling down to the prescribed bins. Electric field in the system is solved numerically, using the fully adaptive higher-order finite element method. The movement of particles in the device influenced by the Coulomb force is determined by means of an adaptive Runge-Kutta-Fehlberg method with a time varying time step. The shape optimization is carried out using a technique based on genetic algorithms. The methodology is illustrated by an example whose results are discussed

Performance comparison of quantized control synthesis methods of antenna arrays

There is a great potential in small satellite technology for testing new sensors, processes, and technologies for space applications. Antennas need careful design when developing a small satellite to establish stable communication between the ground station and the satellite. This work is motivated by the design of an antenna array for a future rotatorless base station for the VZLUSAT group of Czech nano-satellites. The realized antenna array must cover a relatively broad range of elevation and azimuth angles, and the control must be fast enough to track the satellite in low Earth orbits. The paper deals with possibilities of synthesis of quantized control of the antenna array. It compares quantization influence for well-known deterministic synthesis methods. It shows the method for decreasing computational cost of synthesis using optimization approach and presents the multi-criteria optimization as a tool for reaching required radiation pattern shape and low sensitivity to quantization at the same time

Effective impendance of a conductor as a function of its cross-section and frequency

Knowledge of the effective impedance of a conductor carrying harmonic current (particularly of high frequencies) is often very important for design of various devices. Although its frequency-dependent values for conductors of circular cross-section are known, not so much is known about this parameter for conductor of more general shapes. The paper presents numerically obtained relevant results for „cross-type“ and „band-type“ conductors for frequencies ranging from 50 Hz to 500 MHz