Physics, mathematics, and technology

2019 Issue №1

Numerical model operation of the mass transfer of the disperse phase of aerosol in nonlinear wave fields for axisymmetric quasithree-dimensional geometrical statement

Abstract

The article describes numerical modelling of fluctuations of an aerosol column in pipes at resonant frequencies. The author suggests a mathematical model of dynamics of the heterogeneous medium-mix with approximately equal component mass fractions. The mathematical model suggests the solu­tion of a dynamics equation system for each of the mix component. The carrier medium is a viscous, compressible, heat-conducting gas. The dispersed com­ponent of the aerosol is described by the equation of conservation of average density, the equations of the pulse components conservation, the equation of energy conservation. The mathematical model considers interaction forces of gas and particles of aerosol, as such forces is considered, Stokes's force, Ar­chimedes force and force of the attached masses, as well as heat exchange in­tercomponent. Within the system of the equations of mathematical model, eight equations were solved by means of the final and differential algorithm implemented as a program code. The equations of mathematical model were complemented with the corresponding entry and boundary conditions. Ha­ving obtained the numerical model, the author studies the regularities of the re­distribution of the aerosol dispersed component density of in wave fields. The research reveals the influence of droplet size on the distribution of the dis­persed component of a multiphase medium in the process of resonant oscilla­tions in pipes.

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Calculation method of the channel potential possibilities of surface vessel radiocommunication system in the mode of pseudo-random frequency tuning

Abstract

The article is devoted to the definition of methodological approaches to the development of multi-channel duplex radio communication systems that en­sure reliable operation on a surface vessel. The research provides analytical expressions for the calculation of the possible number of transmit-receive channels in the model, depending on the signal spectrum width in the chan­nel. The proposed software allows you to quickly calculate the parameters of the communication system.

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