The analysis of the frequency-controlled drive currently used on the technological equipment of the Volgogradneftemash enterprise is presented. Taking into account the peculiarities of the pumping and ventilation equipment installed at the enterprise, the principles of regulation are determined and the influence of a frequency-controlled drive on the quality of electrical energy is evaluated. The negative influence of the frequency-controlled drive of ventilation and pumping equipment on individual indicators of electricity quality was noted. In order to reduce this influence, an energy-saving device has been proposed for installation. The issues of the possibility of using an energy-saving device at the facility are considered, as well as an analysis of its efficiency during operation from the point of view of improving the quality of electricity in the internal power supply system of the Volgogradneftemash open Joint stock company is carried out. The use of the device is an effective solution, since it leads to high energy efficiency of technological equipment by reducing current surge, suppression of higher harmonics and electromechanical interference.

Keywords: electric drive, ventilation system, frequency-controlled drive, quality of electrical energy, energy saving device

Numerical solution of the problem of heat transfer in the boundary layers of transparent gas wall, exposed on the opposite side of radiant-convective heating. The energy dissipation due to viscosity is negligible, the wall is thermally thin, and the physical properties of the medium do not depend on temperature. The aim of this work - finding the local heat transfer coefficients (Nusselt number) needed for the analysis of heat exchangers. When solving the problem of nonlinear transfer functions linearizing method is used, based on which numerical scheme for computer calculations was constructed. The intensity of the local heat transfer in the boundary layer is determined by the number Kx = Nux / Nux0, where the value Nusselt numbers refer to the conditions under consideration of the problem of heat exchange (Nux) and constant surface temperature (Nux0). From a physical point of view, non-dimensional parameter Kx is a measure of the intensity of heat transfer in the boundary layer on a nonisothermal surface compared to heat transfer when the wall temperature everywhere the same. The analysis of this research showed that in radiative-convective heating number Kx on the front edge of the plate takes the largest value of Kx ≈ 1,37 corresponding to a constant heat flux on the wall. It is also shown that the relative temperature of the incoming flow has a significant impact on the value of Kx. The effect of this setting is especially evident in the processes when dominated by the effect of radiation and related to the nonlinearity of the transfer processes. The analysis revealed the influence of basic parameters of heat transfer on the development of transport processes in the boundary layer by heating radiation and convection simultaneously.

Keywords: Boundary layer, convection, radiation, radiation-convection heating, high temperature gas invironment, linearizing function