Том 46, № 3 (2017)

We have investigated processes of wave mixing in oscillatory-type power plants and presented the results in the paper. The flow in the power plant has been simulated by solving a set of 2D nonstationary Navier–Stokes equations for viscous uncompressible liquid. The flow field was formed by blade vibration and, as a result, the triangle deformed mesh has been used. The marker method has been used as the basic method for calculating the evolution of the admixture. The information of computations is processed using special criteria of the mixture quality. The influence of frequency and amplitude on the mixing intensity has been investigated. The consumed power has been estimated. The obtained information forms a basis for determining optimal modes of power plant operation in terms of power consumption–mixing efficiency.

The mathematical model of dynamics of the electric-power DC drive for actuating links of tripod manipulator with self-breaking transmission has been considered. Analytical conditions of lack of dynamic jamming the drive have been obtained.

The algorithm for calculating the stressed-deformed state (SDS) of thin-walled structures of concatenated shells with different material stress–strain properties on the finite-element method’s base with scalar and vector interpolation of displacement fields has been outlined. The quadrangular curvilinear finite-element with nine degrees of freedom in the node has been used as a discretization element. The SDS analysis of a thin-walled shell structure formed by a cylinder and two jointed shells of dissimilar materials has been performed.

Tests for the wear of polytetrafluoroethylene and composites on its basis with different glass transition and softening temperatures has been performed. It has been demonstrated that a rise in temperature leads to an abrupt rise in wear due to the build up of adhesive on the metallic counterbody. The method of temperature calculations in the frictional contact zone has been developed and tested. It has been demonstrated that the introduction of filler into polytetrafluoroethylene results in a rise in the glass transition temperature from–120°C, which corresponds to polytetrafluoroethylene, to +150°C.

Under the conditions of cyclic loading at fixed joints, the repeated mutual slip of the contacting surfaces is observed in the contact zone, fretting appears, and the wear and destruction of the assembly elements occurs. The existing methods for overcoming fretting are aimed at reducing its intensity. The finite element analysis of fixed joints of smooth contact surfaces and surfaces with relief under the conditions of cyclic loading of junctions makes it possible to reveal the regions of mutual slip and, to determine the parameters of the microrelief, which contribute the most to the onset of contact shakedown. The method for improving the resistance to fretting in friction units based on achieving the conditions for the onset of contact shakedown using microrelief is implemented for fixed joints of a hard-alloy cutter pick and a drilling bit rolling cutter, as well as for an abutting joint of the rotor impeller shrouds of a universal gas distributor.

The work is devoted to describing a technique for the quantitative control of burns during the grinding of high-speed cutting plates made of steel P9M4K8. The technique is based on digital technologies and software systems and involves obtaining a macroscopic light picture, digitizing it, and converting it into raster color images. The method is available for production conditions. Based on the application of this technique, in order to analyze the features of the surface formation during plate grinding, recommendations for optimizing the technological process have been formulated.

The computational results of temperature on the surface of ribbed tubular electric heaters and ribbed pipes of thermosiphons have been presented, the desired airflow rate, and installed electric capacity of fan motors for existing and developed electric air heaters has been determined. The computational results of the temperatures of the ribbed pipes have been compared with the experimental data. The novelty of the development has been confirmed by patents obtained on the invention of the electric air-heater design.

As a result of the probability solution of the condition that the ring stress is lower than the limit stress, the fourth-order algebraic equation for determining the expected value of the wall thickness for the case when the initial parameters are normally distributed has been obtained. The sensitivity of the reliability of an oil and gas pipeline to the variations in the pressure, strength limit, diameter, and wall thickness has been studied, which improved its operation safety.