Том 54, № 7-8 (2018)

The forces acting on the blades of a radial axial turbine and the fluid are analyzed for introduction of the flow into the turbine from outside at an angle relative to a direction of the peripheral speed. The tilt angle of the blade is considered to be constant relative to the wheel radius. The influence of the centrifugal force, for which a certain amount of potential energy of the fluid is needed to be overcome, is estimated. Fluid velocity and blade velocity along with the fluid pressure on a turbine blade and the pressure exerted by the centrifugal force on the fluid are presented as functions of the initial fluid velocity and the peripheral speed of the turbine for different tilt angles of the blade and different flow directions.

In technology and practice, it is often necessary to separate liquid homogeneous mixtures consisting of two phases — solvent and solute. When the densities of the substances differ, gravitational, centrifugal or other type clarifiers can be used for the separation of phases. In the work done based on the example of a water + oil solution, a physico-mathematical model was formulated describing separation of liquid mixtures of this kind in a field of gravity (gravity settler) and in a centrifugal force field (in a liquid centrifuge). Based on the proposed mode of separation of solutions on the considered types of equipment, a numerical simulation is proposed to describe the process of separating the oil phase from the aqueous phase.

A procedure is proposed for calculating the main force parameters during hydrostatic compaction of powder material objects. Internal residual stresses arising during compaction of hard fine media are evaluated. Measures are proposed for reducing them in finished objects.

Methods of restoring the internal surfaces of cylinder plugs of the U8-6MA2 drilling pump with the use of an advanced design of a boring bar possessing a complicated cross-section are proposed. The rigidity and maximal flexure of a boring bar with a machine milled surface are calculated. The economic efficiency of the proposed design is demonstrated, with a 30–40% increase in productivity.

A geared linkage driving mechanism of the drive of a non-stationary mixer the mechanical diagram of which is designed at the level of the smallest dimensions is developed. With such a design of the drive it becomes possible to improve the quality of manufactured products and accelerate the mixing process through continuous intra-cycle variation of the amplitude and angular spin rate of the working bodies.

Calculation of a cooling tower with regular packing using a modified method of the number of transfer units is considered. Diffusion models recorded for gas and liquid phases with volumetric sources of mass and heat, taking into account interphase transfer, are used to account for the mixing of flows. From the solution of diffusion models, unknown coefficients are identified from the number of transfer units. A sample calculation of the layout of a cooling tower with plastic mesh packing is given along with experimental values of the regime and the thermodynamic parameters of water cooling in the cooling tower.

Results are presented for experimental study of a new method for turning workpieces of thermoplastic polymers (caprolon and fluoroplastic), including workpiece advance treatment with ultrasonic vibration. The expediency of using this method is confirmed since advance ultrasonic treatment makes it possible to provide a reduction in the level of workpiece surface roughness, and this is indicated by roughness parameter values and forms of shaving obtained.

The results of optimization of low-temperature refrigerant composition in dual mixed refrigerant cycle by mathematical-analytical method using performance data for increasing liquefied natural gas (LNG) production and decreasing specific energy consumption are reported. The flow diagram of the LNG cycle with dual mixed refrigerant is presented. The advantages of using dual mixed refrigerant cycle are shown.

The results of experimental studies of piston hybrid energy-generating machine having smooth and stepped slot seals are analyzed. It is demonstrated that stepped piston seal is much more effective than the smooth one and raises the delivery factor of the compressor section by more than 10%, reduces the average temperature of the cylinder-piston group by 2–3 K, and enhances volumetric efficiency of the pump section by 3–5%.

The parameters of surface treatment of semifinished products and articles from ferrous metal alloys, including titanium alloys, with low-pressure water-air jets containing refined finely divided particles are studied. The existing techniques are analyzed in terms of economic efficiency and surface quality.

Nickel-graphite bisulfate composite electrochemical coatings (CEC) are prepared. Deposition of these CEC in a galvanostatic regime is studied. Composite coating tribological properties are determined. It is revealed that graphite bisulfate improves coating tribological properties.

Effective technical means of cavitation treatment and dosed deposition of reactoplastic binders using ultrasonic vibrations are analyzed. The technique of variant construction of ultrasonic cavitators with radiative plates is described. The proposed methods of computer-aided design are based on integrated use of parametric models and computer graphics, which together graphically reflect the existing variational relationships between the different elements of the construction of the created articles. As a result this makes it possible to rapidly determine the required dimensions of radiative plates for rational application of their features in a specific technological process.

The first author’s name should read A. B. Kapranova.