Methods of designing and manufacturing a heat exchanger for the small-dimensional gtes with heat recovery

The article describes the method of calculation, design and manufacture of the the plate heat exchanger for the gas turbine plants with heat recovery. We represented the method of threedimensional calculation, which allowed conducting a virtual experiment and clarifying the design of the heat exchanger for the given parameters. We presented the results of experimental studies, which allowed predicting and determining optimum parameters of a plate heat exchanger for various schemes of gas turbine engines with heat recovery.Keywords: small-sized gas turbine engine, heat exchanger, the method of designing, improving the design, increasing efficiency

Improvement of friction units of power plants by aplying ceramic composite spray coatings

Modifying the working surface of a product by applying protective and functional coatings makes possible considerable changes in the mechanical, optical, electrical, magnetic, thermal and chemical properties of the original structural material, its real surface, producing articles with protective, for example, anti-corrosion, wear-resistant and other properties. We investigated the possibility of improving the friction units of aircraft power plants by applying nanostructured ceramic composite spray coatings. A heavily loaded bearing forming a part of the gearbox of a turbojet engine is used as a prototype of the friction unit. The advantages and drawbacks of improved friction units as compared to production models and their prototypes made according to an improved technology are assessed. The results obtained during the experimental work are presented. A positive conclusion is made about the use of nanostructured composite materials in the development of friction units; the most favorable method of coating is determined

Assuring performance characteristics of gas-turbine engine parts and assemblies using electrospark doping

The article describes surface hardening of aircraft engine titanium-alloy hydraulic cylinder face using the method of electro-spark doping by low-energy discharges. Graphite electrodes were used to provide functional behavior of the cylinder surface layer. The carbon oxide layer formed has a highly dispersed structure of a complex composition (with particles of titanium carbide, titanium oxide, graphite), 3-10 micron thick, characterized by high hardness and sliding properties. Graphite electrode alloying practically does not change the part dimensions. Subsequent diamond burnishing of the hardened surfaces decreases the value of the friction coefficient and surface roughness. Healing of defects and micro-cracks improves the fatigue resistance of the part. The developed technology makes it possible to assure the characteristics required of hydraulic cylinder work surfaces and increase their life

Method for optimizing mass and size characteristics of a high-pressure turbine disk

The article presents the results of weight and size optimization of a high-pressure turbine working disk for an augmented turbofan. The issues of modeling the operation of the engines first stage with a cover plate providing the delivery of cooling air to the blades are considered. Strength calculation of the stresses arising from the action of centrifugal forces under high-temperature conditions was carried out. A three-dimensional model of the disc was obtained. The finite element method was used. The pattern of temperature distribution in the disk body was obtained on the basis of heat calculation. Based on the strength calculation, the stresses and strains of the turbine disk were determined. Maximum stresses in the disc are located at the junction of the disc frontal area and the cooling air feed holes. Plastic deformation is observed in the area of the cavities for cooling air feed. It is shown that the stepped part of the disc should be made of a material with lower heat resistance and a higher value of permissible limit stress. Based on the study, a bimetallic disk design made by powder metallurgy was proposed

The problems of creating a propulsion system of a new generation supersonic passenger aircraft (review)

The problems of creating a propulsion system for a new generation supersonic passenger aircraft are considered on the basis of a review of the work on the supersonic transport being carried out in the world. It is shown that the desire to achieve high flight performance and commercial effectiveness of a supersonic passenger aircraft while meeting up-to-date environmental requirements leads to contradictory technical solutions regarding the propulsion system: the location and number of engines, the scheme of the air intake and nozzle, the choice of the scheme and design parameters of the engine, the use of new high-temperature materials in the engine hot section, etc. The features of the operating conditions of the engine components of a supersonic passenger aircraft in comparison with the engines of up-to-date subsonic civil aviation aircraft and supersonic military aircraft are indicated. The calculated estimates of the influence of various technical solutions on the parameters of the supersonic passenger aircraft engine are given. Due to the complexity and multi-criterion nature of the task of creating a supersonic passenger aircraft propulsion system, its solution requires an integrated approach based on close cooperation of specialists in airframe aerodynamics, engine, etc