Resonant Parametric Photon Generation in Waveguide-coupled Quantum Emitter Arrays

We have developed a theory of parametric photon generation in the waveguides coupled to arrays of quantum emitters with temporally modulated resonance frequencies. Such generation can be interpreted as a dynamical Casimir effect. We demonstrate numerically and analytically how the emission directionality and photon-photon correlations can be controlled by the phases of the modulation. The emission spectrum is shown to be strongly dependent on the anharmonicity of the emitter potential. Single- and double-excited state resonances have been identified in the emission spectrum.Comment: 10 pages, 7 figure

Comparative analysis of two-dimensional and three-dimensional modeling of heat transfer during operation of a gas infrared heater indoor

Relevance. It is proposed to heat local work areas with systems based on gas infrared heaters, capable of directing radiative heat flow to reduce heating costs in large premises. However, the widespread use of gas infrared heaters is hampered by the existing difficulties with the preliminary assessment of convective-radiative heat flows movement, on which the number and location of heating devices depends. The preliminary assessment is complicated by the need in some cases for 3D modeling of complex physical processes. It is necessary to evaluate the possibility of replacing labor-intensive 3D modeling with a method for calculating a heating system using gas infrared emitters based on a 2D approach to reduce the time spent on calculations. Aim. To prove that the use of a two-dimensional model of the processes under consideration makes it possible to obtain the main characteristics of the thermal regime of the premises, making it possible to replace spatial modeling. Objects. Heating system with a light-type gas infrared heater and an air exchange system. Methods. Two-dimensional and three-dimensional mathematical modeling of conjugate heat transfer processes using the finite element method. Mathematical modeling was carried out in the COMSOL Multiphysics software environment using the modules: “Heat Transfer Interface in Liquids”, “Radiation between Surfaces” and “Turbulent Flow, k-ε Interface”. Results. The article presents the results of mathematical modeling performed in three-dimensional and two-dimensional formulations. The distribution of temperatures in the air and enclosing structures, as well as the flow lines of heated air and air, which was heating, in the volume of the premise are presented. The results of two-dimensional and three-dimensional modeling were compared. Satisfactory similarity of the calculated average air temperatures in the local working area was established based on the results. The difference was less than 2℃ for different spatial modeling approaches

NUMERICAL ANALYSIS OF THE INFLUENCE OF THE AIR EXCHANGE SYSTEM CONFIGURATION ON THE TEMPERATURE REGIME OF LOCAL WORKING AREAS IN A ROOM WITH A GAS INFRARED HEATER

The relevance. The most promising option for an energy-efficient system for ensuring the scheduled thermal regime of local workplaces, which occupy a small area in large workshops, are the so-called «radiant» heating systems, the main part of which are gas infrared heaters. The main role in the formation of the thermal conditions of the local working area is played by the process of mixed convection (the air movement due to its heating by enclosing structures and flows that form the air exchange system). The analysis of the influence of the location of the air exchange system channels on the thermal regime of the local working area using a gas infrared emitter has not been performed so far. The main aim of the research is to analyze the influence of the position of the air exchange system’s openings channels on the temperature fields of local working areas near the equipment model based on the results of mathematical modeling. Objects: heating system using high-intensity gas infrared heater and air exchange system. Methods. Mathematical modeling was carried out within the framework of a two-dimensional model of conjugate heat transfer using the finite element method. The modules «The Heat Transfer in Fluids Interface», «Surface-to-Surface Radiation» and «The Turbulent Flow, k-ε Interface» of the COMSOL Multiphysics software environment were used for the numerical analysis of heat transfer processes Results. The paper introduces the results of mathematical modeling carried out to determine the influence of the position of the air exchange system’s channels on the temperature fields and the possibility of controlling the process of a scheduled thermal regime formation in local working areas when using a gas infrared heater. The temperatures and velocities fields, as well as the air temperature distribution along the height of the local working area for various options of the air exchange system’s inflow and outflow areas location are presented. Based on the results of the research, the main regularities of the processes of heat and mass transfer under the considered conditions were revealed. The possibility of controlling the processes of thermal regime formation of local working areas by varying the air exchange system channels position was also revealed

The finite element method for modeling spherically symmetric pulsations of the earth

Рассматриваются вопросы математического и численного моделирования геодинамических про- цессов расширения, сжатия, разогревания и охлаждения Земли.Some problems of mathematical and numerical modeling of geodynamic processes of expansion, compression, heating and cooling of the Earth are considered

The finite element method for modeling spherically symmetric pulsations of the earth

Рассматриваются вопросы математического и численного моделирования геодинамических про- цессов расширения, сжатия, разогревания и охлаждения Земли.Some problems of mathematical and numerical modeling of geodynamic processes of expansion, compression, heating and cooling of the Earth are considered