Vol 13, No 5-3 (2014): Special Issue

Rapid prototyping technologies provide a unique opportunity to receive cost-effective solutions for the production of parts by investment casting. Research and development of rapid prototyping technologies allowed to move to a next level of optimization and the introduction of new processes in various areas of industry. At the stage of pilot production, which is characterized by frequent changes in design, the problem of the rapid production of cast components becomes crucial. This is mainly due to the complexity and the complexity of manufacturing foundry equipment. In turn, the research and development of rapid prototyping technologies have allowed a new level of optimization and the introduction of new technologies in the investment casting. The aim of this work is to identify opportunities and evaluate accuracy of the size of the casting during investment casting using rapid prototyping technology. The work was conducted with the use of cross-cutting design in CAM/CAD/CAE systems. The study size and precision parameters of the casting was conducted in coordinate measuring machine. The work has been verified the adequacy of the virtual simulation of the process of forming a casting in the casting simulation ProCAST, in comparison with those obtained castings. The study showed that the use of rapid prototyping technologies with investment casting can significantly reduce the time for making castings, reduce production costs and improve the accuracy of the size of the casting.

The article presents the results of an experimental study of the thermal parameters and with-standing experimental samples rocket engines gaseous oxygen with thrust 25 N and 100 N. In experimental models rocket engines thrust 25 N and 100 N ignition fuel components arranged in the discharge chamber spark plugs. Scheme carburetion of engines characterized by the interaction of coaxial swirling flows of fuel and oxidant is carried out in two stages. At the same time, realized highly turbulent flow, contributing to the efficient mixing of fuel and oxidizer in a limited volume of the combustion chamber. Cooling chamber traction motor 25 H organized using a gas curtain of fuel from the mixing head and the application of high temperature structural material – boronsiliconized graphite, which is made of a combustion chamber and a nozzle. In rocket engines thrust 100N further organized subsonic curtain fuel located at the end of the cylindrical portion of the combustion chamber, but at the same time as the construction material used stainless steel type 12X18H10T. Experimental studies have been tested two structural variants of organization of the ignition process, evaluated the effectiveness of the scheme of mixing hydrogen and oxygen gases. In this case, the following values of specific impulse engines: for rocket engines thrust 25H with the geometric expansion ratio of the nozzle Fа = 45 - 3846 m/s; for rocket engines thrust 100N with Fа = 45 and Fа = 250 – respectively 3855 m/s and 4100 m/s. From the point of view of the thermal state in the study design rocket engines propellants, promising is the use of new construction materials, such as ceramics, graphite-based materials with the development of the technology for their production, as well as interfacing to the mixing head, made, usually made of stainless steel. In support of the above, in the use of the camera rocket engines thrust of 25N boron-siliconized graphite allowed during the test the engine for 100 seconds to get the maximum temperature of the outer surface of the chamber at ~ 1045 ° C.

With respect to aeronautical engineering it is focused on the problems of the dynamic strength of parts and units of aircraft engines, namely the resistance of the material under the action of various oscillatory processes (vibration) arising from the operation of such engines. An important aspect of this problem is to ensure the safety of flight in atmospheric icing conditions. Relevance of study is determined, above all, the lack of study of the processes of icing. The paper summarizes the results of processing the experimental data obtained in a test of gas turbine engines in icing conditions at a specialized ground test rig. The stages of the process with regard to icing vibration condition of the engine. In the course of experiments on icing were found in the spectrum of the vibration diagnostic signs of the blades self-oscillations. One of the probable causes of such hazardous processes may be throttling the fan due to ice build-up on the blades straightener or on input parts of the fan. However, for a more detailed description of these phenomena occurring in icing conditions, additional studies, experiments, calculations. This article describes the features of the study of vibrating processes in the engine in such trials. It is discussed the directions for further research on this issue.

The peculiarities of short-term resistance to tension/compression, creep, long-term strength and thermal fatigue of single-crystal superalloys for different crystallographic orientations and temperatures are considered. The failure criteria are proposed using a unified measures equivalent stress (strain) for the cubic system, allowing to compute adequate strength and durability of single crystal materials under complex multi-axial inhomogeneous stress state, which is characteristic for gas turbine engine blades during the operation.

The development of small and unmanned aircraft in Russia is hampered by the lack of production of domestic aircraft engines in the power range up to 200 h.p. The main requirement for the aircraft engine is minimal ratio of mass and overall dimensions to output. In a greater degree that is matched by the engines of rotor piston layout. The intensive work on rotor piston engines is carried out abroad by companies of many countries: Britain (UAV), USA (Freedom Motors), Austria (Austro engine) etc. In Russia, at SKBM the works on rotor piston engines were conducted for outboard motor application in cooperation with Rotor Piston Engines Design Bureau of AVTOVAZ. For the satisfaction of needs for small and unmanned aircraft a project of creation of rotor piston engines in the power range of 8-200 h.p. was developed.

The methods of grinding the spherical ends of tapered rollers using the wheel end and periphery are considered. The ways of improving the accuracy of the spherical end when processing using the periphery of a grinding wheel, radially refilled, and ensuring the surface quality due to uneven wear of a wheel are shown. It has been established that increasing the efficiency of grinding the spherical surfaces of a roller is carried out by reducing random and systematic error components of processing. The results of grinding using the corrected radius and the processing device for continuous grinding of spherical roller ends are represented. The structure of surfaces of spherical roller ends using the optical-electronic complex that could reduce the influence of the cur vature of the surface under study on its image is investigated. An algorithm of using binarization of an original halftone image for analyzing the structure of the treated surface, which provides processing and output of the results on the PC screen is considered. The binary images of the surface structure of spherical roller ends with different roughness are shown. The studies of the effect of the average amplitude of oscillation of the autocorrelation function depending on the surface roughness are performed. Thus, the relationship of roughness of the surface profile with the parameters of the autocorrelation function is shown. The optimum parameters of the surface structure, the amplitude of the autocorrelation function and the mathematical expectation that will provide an increase in performance properties of the contact surfaces are determined.

The article describes the concept of a virtual lab that includes subsystem of gas turbine engine simulation, subsystem of experiment planning, subsystem of measurement errors simulation, subsystem of simulator identification and others. The basis for virtual lab development is the computer-aided system of thermogasdynamic research and analysis “ASTRA”. The features of gas turbine engine transient modes simulator are described. The principal difference between the simulators of transient and stationary modes of gas turbine engines is that the energy balance of the compressor and turbine becomes not applicable. The computer-aided system of virtual gas turbine engine testing was created using the developed transient modes simulator. This system solves the tasks of operational (throttling, speed, climatic, altitude) characteristics calculation, analysis of transient dynamics and selection of optimal control laws. Besides, the system of virtual gas turbine engine testing is a clear demonstration of gas turbine engine working process and the regularities of engine elements collaboration. The interface of the system of virtual gas turbine engine testing is described in the article and some screenshots of the interface elements are provided. The developed system of virtual gas turbine engine testing provides means for reducing the laboriousness of gas turbine engines testing. Besides, the implementation of this system in the learning process allows the diversification of lab works and therefore improve the quality of training.

Rolling with various forces influence on the endurance limit of specimens made of steel 20 of 50 mm diameter with cuts of various radiuses and pressurized bush has been examined. The estimation of the surface hardening influence on the specimens endurance limit has been carried out using two criterions, namely: residual stresses on the dangerous section surface and the average integral residual stresses through the dangerous section thickness, equal the fatigue non-propagating crack critical depth. On base of carried out experiments it’s been established that the employment of the average integral residual stresses criterion is more rightful for the endurance limit prediction of surface hardened cylindrical specimens made of steel 20 with diameter 50 mm with cuts and pressurized bush taking into account the concentration degree. The residual stresses on the concentrator surface is not acceptable as a criterion for the endurance limit prediction of surface hardened specimens made of steel 20 with cuts and pressurized bush because the corresponding coefficient of the criterion influence on the endurance limit has a essential dispersion. Besides, the dependence of the fatigue non-propagating crack critical depth on the specimen (part) dangerous cross-section sizes has been confirmed.

Results of formation of structure of an assortment from the technical cleanliness titan depending on coarse-grained or nanostructural state for maintenance of mechanical properties received by various ways of details of assemblages are presented. The structure of the titan depending on conditions and character saturation by hydrogen is studied at machining. It is established that modes on character of technological deformation of preparations render proskating rinks of strips and sheets hereditary influence on fluctuations of mechanical properties of metal on its area and a thickness. It is shown the results of studies link changes in crystallographic texture samples of titanium with the nature of the formation of the microstructure of the alloy in the technological processes of hot plastic deformation on the example of cylindrical samples of two-phase titanium alloy VT9 under various schemes application of stress and strain in machining, tension, torsion, ching.

Compressor blades are the most complex and critical parts of a gas turbine engine. It is driven by the cost of their production, as well as the requirements in terms of reliability and service life. A promising method for manufacturing the blades is a pulse electrochemical machining (ECM), the main advantages of which are the lack of power and thermal effects on the treated surface, the longevity of the tool, at low values of roughness parameters when working at high current densities in high-precision copy form and stability during operation of the process at a sufficiently small interelectrode gaps. In this paper we have set out the principles for the implementation of the model applied to the electrochemical shaping pulse echo that will deliver engineering simulation methodology for processing and profiling tool electrode in a real production. In solving the problem of electrochemical formation, taking into account the factors influencing the process was proposed algorithm describing the process of pulse echo, which was based on the use of a numerical method for sample processing in time and space. This algorithm will automate profiling tool electrode during pulse electrochemical treatment.

An estimation method for weight and size characteristics of complex propulsion unit (CPS) of the Earth remote observation spacecraft determination based on calculations of required characteristic velocity needed to carry out various kinds of maneuvering is proposed. Program complex for automated posing and solving of design problems by choosing the design characteristics of CPS is developed based on a problem-oriented programming and implementing the exact approximation concept. Within the concept, optimization of CPS basic design parameters is carried out in implicit form, without setting the mathematical programming problem, which requires formulation of objective functions and limitations. Software package developed in the programming language Java is described. Use of the package is illustrated by determination of CPS parameters needed to provide given characteristic velocity for the spacecraft with given mass. In order to perform quick comparative analysis of alternative design versions of CPS, the package provides import of calculated design parameters into 3D design system wherein original parameterized CPS model may be preliminarily constructed.

The adaptation to a new design and manufacture technologies of products is related with necessity for forming а new of thinking of professionals. A more research should be given to learning 3D modeling. A description of processes of educational activities is presented in the form of contextual diagrams IDEF0 – models for preparing specialists at the Faculty of aircraft engines SSAU, its decomposition by type of training. The goals of the Engineering graphics department, in addition to knowledge of the creation 3D modeling, are learning the basics of document management and methods of standard models’ parameterization and their using. At the same time a number of problems is being solving: a gradual (from the beginning) familiarization with capabilities and a consequent acquisition of skills in an environment of modern integrated CAD / CAM / CAPP systems; an optimal solution of descriptive geometry, in particular, using and development of spatial imagination, the exact solution of the metric and positional problems; achievement the new level of geometrical-graphic preparation by using parametric models for performing 3D details, automated construction the drawings on a plane with GOST rules ESKD, which significantly reduces the routine work in creating technical documentation for the following departments. Realization of this approach in training specialists allows to use a 3D model constructions for engineering analysis of their functioning in the conditions of use, as well as to model a manufacturing process in the virtual space.

The possibility to use the Dirt Alert diagnostic layer to diagnose PS-90A engines equipped with QA-07930-01 filter elements by Pall Corporation is shown. Division of Dirt Alert diagnostic layer into parts according to their height allows to get wash samples and to make diagnostics of PS-90A engine without disassembly and replacement of main filter element before completion of its mission. Device and ultrasound methodology of wear debris particles extraction from diagnostic layer are developed. It is determined that wash sample presentability is provided by single passage of diagnostic layer in tape drive during 20 minutes. The possibility to use a statistical model of operational PS-90A engine equipped with the filter element without diagnostic layer that had been previously developed basing on wash sample analysis in order to make a diagnostic decision on PS-90A engines equipped with QA-07930-01 filter element is considered. In this model, wear debris particles ratings are used as diagnostic parameters. It is shown that parameters of wash sample wear debris particles extracted from diagnostic layer of QA-07930-01 filter element do not differ from QA-07930 filter element wash sample particles parameters. It means that PS-90A engine equipped with QA-07930-01 filter element technical state evaluation is possible with use of the statistical model of operational PS-90A engine equipped with the filter element without diagnostic layer developed basing on scintillation analysis of wash sample taken from QA-07930 filter element. The conclusion is made that perspective direction to get express and reliable results of technical state evaluation for PS-90A engine lubrication system is to equip engines of this type with QA-07930-01-type filter element.