I. Yu. Kruchinina

Some problems of the high-speed permanent magnet miniturbogenerators development

Investigations for developing ultimate rating microturbogenerators based on modern materials were executed. Maximum permissible electromechanical and mechanical loads depending on minimum permissible core dimensions for microturbogenerators with rating of 100 and 200 kW and speed of rotation 30000-100000 rpm are determined. Complex simulation models for the purpose of chosen generator parameters optimization and for 3D contact problems decision based on numerical finite element method are worked out. For principal decision of mechanical problems for microturogenerator with rating of 200 kW and speed of rotation 100000 rpm and more, its necessary to use new materials of higher strength. Consequently the most essential physical characteristics of strip cylinder materials which exert influence on the geometric dimension changes limits were find out to raise microturogenerator capacity.

Ceramic nanocomposites based on oxides of transition metals for ionistors

Low-temperature synthesis methods are used to produce nanoceramic materials for electrodes of the following ionistors: (ZrO2)0.6(In2O3)0.4, praseodymium cobaltite, as well as neodymium, lanthanum, and nickel chromites; they operate in the presence of an ion-conducting phosphorosilicate separator membrane and phosphate impregnation. Film electrodes of ionistors are fabricated that consist of nanocrystalline oxide materials deposited as a thin film on a porous electroconductive metal substrate, i.e., foamed nickel. The MnO2-foamed nickel electrode has a specific capacity of 45.0 F g−1, which is compared with that of industrial supercapacitors.

The influence of the particularities of synthesis on the physicochemical properties of nanosized powders and ceramic samples of REE orthophosphates

Sol–gel synthesis of La1–xYxPO4 · nH2O orthophosphates has been conducted via a method of reverse precipitation, and the obtained powders have been studied with X-ray phase analysis and simulteneous thermal analysis, including differential scanning calorimetry and thermogravimetry (DSC/TG). For the ceramic samples obtained from the powder, the microhardness has been determined depending on the temperature of the heat treatment. The thermal behavior of the samples has been studied via the method of dilatometry.

High-speed synchronous machines: A computer system for the study of the effect of rotor radial eccentricity on electromagnetic forces

The problem of the development of modern bearings (magnetic, gas, etc.) for high-speed machines with a wide range of capacities (from tens of kilowatts to megawatts) and rotational speeds (from 6000 to 60000 rpm) used in oil and gas production, robotics, space technology, and mini gas-turbine power plants is considered. The distribution of forces applied to the rotor shaft in different modes of operation is investigated including the case of shaft eccentricity. In operation, the eccentricity should not exceed 5%. A computer system is designed on the basis of the numerical method for field (2D) computation in the active part of the machine. The distribution of forces is analyzed taking into account the saturation of the magnetic circuit of the machine and the harmonic content of the mutual magnetic flux (flux in the gap). When calculating these forces in the no-load mode of operation, it was assumed that, in machines with permanent magnets, the mutual magnetic flux on the rotor is about 10–15% higher than under the rated load because of the demagnetization effect of the armature reaction. The mutual magnetic flux was specified depending on the type of rotor magnets. The computer system takes into account the relative position of the rotor poles relative to the stator field reaction under load (load angle Θ). It is also taken into account that, during use, the resulting mutual magnetic flux is distorted (compared to the no-load mode). As a result, a number of additional high harmonics appear in the gap, which affect the forces applied to the rotor shaft. Load angle Θ is calculated using graphical options of the simulation package by the iteration method. An algorithm for the implementation of this method is described. The distribution of the radial forces along the rotor shaft surface (differential parameter) and the total radial attraction force applied to the rotor shaft (integral parameter) are calculated for different values of eccentricity and different modes of operation of high-speed machines.

Sol-gel synthesis and the study of the surface of epoxide-siloxane and epoxide-titanate coatings

Three compositions based on epoxide-siloxane, epoxide-titanate, modified epoxide-titanate sols have been synthesized by the sol-gel method, and the morphology of surface and the hydrophobicity of coatings obtained on their basis has been studied. According to the results of the studies, the compositions of the coatings have been chosen for the conduction of tests on a rotor of high-rpm miniturbogenerator, with the aim to determine the effect of aerodynamic losses.

Design considerations of submersible unprotected solid-rotor induction motor

This paper deals with alternative solution of submersible sealed oil-extended motor - submersible unprotected solid-rotor induction motor of 12/18 kW, 750/1500 V, 3000/6000 rpm, which can operate inside oil well, in corrosive medium-strata liquid (mixture of oil, associated water, mineral admixture and oil gas) with ambient temperature 1500degC and pressure 30 MPa. To estimate the performance of the solid rotor motor two-dimensional (2D) nonlinear complex time-harmonic solver is constructed to model the machine in steady-state. Non liner magnetic material characteristics, the different rotor construction were taken into account.

Nanopowders of orthophosphate LaPO4-YPO4-H2O system and ceramics based on them

Nanopowders of orthophosphate LaPO4-YPO4-H2O system have been synthesized via the solgel method, and the limits of the mutual solubility of components have been specified through the calculation of the parameters of the unit cell. The dense ceramics were prepared based on the La1 − xYxPO4 · nH2O nan-opowders at 1000 and 1200°C. The porosity, microhardness, and bending strength of the ceramics were determined, and the dependence of the microhardness on the calcination time was established. The thermal behavior of the samples was studied by dilatometric method and the thermal coefficient of linear expansion of the ceramics was estimated.

Promising electromechanical energy converters based on new materials and coatings

The efficiency of new materials and the application of coatings for promising high-speed electromechanical energy converters has been estimated. A new basic model of miniturbogenerator intended for testing new materials and coatings has been developed. The experimental results obtained for pilot samples with different organic-silicate coatings show that the losses in the rotor decrease.

Structure and proton conductivity of a hydrated Nafion-115 membrane

Nafion-115 membrane hydration has been carried out by the treatment with hydrochloric acid solutions of various concentrations (0.025–3 M). The structure and electrophysical properties of the original untreated Nafion membrane and hydrated membranes have been studied. The current–voltage characteristics of the membrane electrode assembly of a fuel cell with the hydrated membrane have been analyzed.

Prospective permanent magnet turbogenerator design for local power engineering

This paper deals with the design of the high speed turbogenerator of 6000 kW rating at 12000 rpm for local power engineering having raised technical and economic parameters. Some questions of the optimal construction with mechanical and electromagnetic characteristics are estimated. For principal decision of mechanical problems for turbogenerator its necessary to use new materials of higher strength. Recommendations at the choice of proper rotor materials are given and opportunities of decrease in loss are estimated.