Centrifugal pumps are the most extensive class of dynamic hydraulic machines, which are commonly used. So-called hermetic pumps, which possess a number of calculation and design features, stand apart among these machines. Rather complicated task is to calculate internal tracts of the hermetic pump, which are used to cool and lubricate its units. The article is concerned with this calculation, namely, the study of the hollow flow. In designing the hermetic pump, when simulating the flow through the accessory tracts, a so-called “lock” effect was detected between the rotor end and the side cover. This effect is caused by a macro-vortex formed in the hollow, which resulted in a significant pressure drop at the inlet of the shaft opening. Such a pressure drop leads to reducing fluid flow through the accessory tracts, which can cause overheating and failure of the engine and bearing units. In view of the large width of the hollow under consideration, to describe theoretically its flow is difficult. Therefore, a numerical simulation is the most accurate way to determine the impact degree of the macro-vortex on the flow process. The article shows a mathematical model used in computer modeling. Presents the images of a flowing part of the accessory tracts and the computation mesh. Also, gives the models to construct a mesh and the boundary conditions desirable to provide hydrodynamic calculation. Then, describes the possible ways to eliminate the “block” effect, i.e. to set an additional impeller, completely change the configuration of a flowing part of the internal tracts, as well as to add the stator blades to the side cover. The latter option was chosen, as the most optimal in terms of labor intensity and manufacturability. Further, to compare the nature of the flow with the blades and without them the article shows pressure distribution fields, vectors of velocity, and turbulent kinetic energy values. All the results obtained, including experimental ones, with errors are presented in the summary table.

Contemporary design solutions in the engine engineering are aimed at raising a great many technical and economic performances, and enhancing manufacturability. When producing the V-shaped six-cylinder engines, the camber angle is often taken to be equal to 90°, which is technologically advantageous in the production of V8 engines. However, this solution leads to the engine instability and deteriorates mass-dimension and vibration performances of the engine. A crankshaft with the offset connecting rod journals is the solution to which Western and Russian power plant developers have increasingly taken recourse. However, introducing such a shaft entails a number of difficulties, and what is the most important requires special methods of calculation.

There are no direct analytical methods to calculate this type of crankshafts. The article describes a technique to estimate endurance using a software complex "KVAL", developed at the BMSTU Department "Piston engines". This software disables direct examination of the crankshaft of this type, however, in conjunction with other calculations enables estimating endurance.

The main point of the technique is a two-staged calculation. The original crankshaft is represented at first as a crankshaft with the connecting rods, sitting side-by-side. The article studies its endurance in the fillets of the rod bearing journal transition to the cheek and also at the outlets of two oil-feed holes. The second stage presumes that the shaft has an articulated rod and using the same type of calculations studies the fillet transition of the rod bearing journals to the intermediate cheek by its representation as an oil hole.

Each of the stages refines theoretical coefficients of stress concentration through numerical simulation in the software package "ANSYS", thereby making calculation more stringent.

The results obtained are very evident and representative, but also allow us to suggest a number of hypotheses for further research.

The proposed technique enables us to study endurance of the crankshafts with offset connecting rod journals, as well as the Napoleone crankshafts of opposed reciprocating engines.

Components of optical systems for various purposes include optical elements with structured surfaces, i.e. linear and circular Fresnel lenses. The objective of the conducted studies is to analyse design parameters and technological development of modes and conditions to ensure manufacturing circular Fresnel lenses with specified technology requirements.

The subject of the study is a circular Fresnel lens, which has a thickness of 2 mm and a diameter of 76.7 mm; its processed profile consists of 126 concentric rings with a valley pitch equal to 0.3 mm. The profile depth of the rings varies from 2.1μm to 337.4μm, with the profile angle varying from 0.406 ° to 48.361 °. The lens material is polymethyl methacrylate (PMMA) - a tough amorphous polymer, which has high transparency, weather resistance, good physical-mechanical and electrical insulating properties.

The article presents the results of applied research related to diamond machining of a Fresnel circular lens. Substantiates that there is a need to use an ultra-precise machine for lens processing and gives its main technical characteristics.

The design features and recommended domestic and foreign diamond mono-crystalline cutters for preliminary and finishing processing of structured surfaces, including Fresnel lenses are analysed.

The technology of diamond edge cutting machining of lenses is proposed, the modes and conditions of diamond turning to exclude finning are given.

The results of metrological control have confirmed the requirements for the profile accuracy and the roughness of surfaces machined.

 The JSC "VNIIINSTRUMENT" has implemented the developed technology on the ultra-precise specialised NC machine and recommended its use in machining the structured plexiglass surfaces of various sizes for different purposes.