Volcanic ash – a hazard for gas-turbine engines

The article briefly examines the topical issue of ensuring flight safety when entering volcanic ash clouds, which can lead to ash deposits on the turbine’s first-stage guide vanes of an aircraft gas turbine engine. CIAM’s experience with investigating a similar issue is described, specifically regarding deposits of Central Asian loess dust of similar composition on vanes of a ground vehicle’s gas turbine engine. The article also includes the schematics for the specially-designed model test bench and the measurement system used for registering the gas temperature upstream of the guide vanes. Analysis of the test results allowed us to determine the extent of the influence of the following key factors on deposit formation: gas temperature upstream of the vanes, level of air purification within the air cleaner, vane wall temperature, duration of dust particle heating, and the roughness of the guide vane walls.

Keywords: volcanic ash, turbine, guide vanes, turbine vanes, ash deposits, test bench

Rysin L.S., Mokrous M.F.

Production of high-temperature reinforced SiC/SiCw ceramics using spark plasma sintering for aircraft engine development

The strategy for creating advanced aircraft engines involves research into the development of parts and products based on silicon carbide and ceramic composite materials. This research aims to produce a ceramic composite material based on silicon carbide (SiC) with a reinforcing additive in the form of silicon carbide whiskers (SiCw) by applying the spark plasma sintering. The dynamics of shrinkage of the powder mixture during sintering in different modes of SiC/SiCw ceramics with a reinforcing additive in the amount of 1, 3 and 10 wt. % has been studied. The shrinkage dynamics of the powder mixture during sintering of SiC/SiCw ceramic composites at different modes and with various amounts of reinforcing additives (1, 3, and 10% mass percentages) have been investigated. The composition, structure and properties of SiC/SiCw ceramics have been studied. The influence of the reinforcing additive and sintering modes on the structure-base states, relative density, microhardness, heat capacity, thermal diffusivity and thermal conductivity of SiC/SiCw ceramics has been investigated.

Keywords: ceramics, ceramic composite material, silicon carbide, reinforcement, whisker, electric pulse sintering, spark plasma sintering

Papynov E.K., Shichalin O.O., Chuklinov S.V., Sergienko V.I., Marchukov E.Yu., Belov A.A., Buravlev I.Yu.

Calculating the stepped-lap adhesive bonding of a rod made of polymer composite materials by the finite element method

The paper is dedicated to the study of the influence of thermocyclic loads on the strength of the adhesive stepped connection of structural elements made of polymer composite material (PCM). The results of finite element modeling of a stepped-lap adhesive joint of a PCM rod before and after heat transfer are considered. It is shown that the stress state is distributed unevenly along the adhesive seam. The destruction of the adhesive joint begins with the outer layers due to the greatest bending deformation.

Keywords: polymer composite material, thermocycling, adhesive bonding, solidification, stress-strain state, finite element method

Nikitin S.N., Zhernakov V.S., Solovyov P.V.

A nonlinear programming algorithm at the stage of preliminary design of a rotating disk

The rotating disk design algorithms that take into account the design requirements are examined. It is shown that considering the conflicting restrictions imposed on the disk construction requires the use of nonlinear programming algorithms, which, due to the “curse of dimensionality”, lead to increased program complexity and require significant computational costs to obtain an optimal design when the number of restrictions and control parameters increases. In the article, as an alternative, a rotating disk preliminary design algorithm based on the sensitivity analysis method, which carries out the solution of direct and adjoint problems for finding the gradient of the target function at each design approximation, is proposed. It is shown that the algorithm of the sensitivity analysis method significantly reduces the solution time when the number of design control parameters in the optimization problem increases. There are examples, which demonstrate the effectiveness of the proposed algorithm in the problem of designing rotating disks of gas turbine engines.

Keywords: optimization, turbomachine disk, gradient of the target function, sensitivity analysis, adjoint vector, preliminary design

Temis Yu.M., Karakusha D.A.

Analysis of the potential of artificial intelligence applications in the technical definition and development of the next-generation aircraft gas turbine engines

The article discusses the issue of creating the artificial intelligence (AI) systems for the purpose of developing the technical layout of the next-generation aviation gas turbine engine (AGTE). The architecture of the future AI system has been developed to analyze and forecast the technical layout of a new AGTE. The method of algorithmizing the information block of the morphological generalized AGTE layout has been proposed, the special identifiers of N.(x, y, z,… )n type, where N Î n Î have been introduced into the architecture of AI system. It has been demonstrated, that the employment of modern AI systems can significantly reduce the material and time expenditures associated with the development of a new engine.

Keywords: gas turbine engine, artificial intelligence, statistics, data processing, forecast of technical layout

Marchukov E.Yu., Vovk M.Yu., Kulalayev V.V.

The boundary element method for steady state thermal analysis of cooled turbine blades

The boundary element method for nonlinear steady-state thermal conductivity problem in a two-dimensional formulation is presented. Temperature dependence of the thermal conductivity coefficient is taken into account using Kirchhoff transformation requiring only a domain boundary to be meshed for calculation. Newton’s and Picard’s methods with relaxation by Aitken’s method are used for the problem’s linearization It is shown that for the same level of solution accuracy different methods should be used to obtain minimal computational time depending on the mesh size. Test problem solution and calculation of the thermal state of the turbine blade are provided.

Keywords: thermal conductivity, radiative heat exchange, boundary element method, Newton’s method, Picard’s method, Aitken’s method

Temis Yu.M., Lazarev A.A.

Optimization of strain gauge placement layout for determination of dynamic stress fields in gas turbine engine blades

The problem of the optimal placement of strain gages on the blade surfaces in terms of information content is considered in order to provide tests for determining dynamic stresses in the blades, a complex and time-consuming stage in the development of gas turbine engines. The solution to the optimization problem is based on calculating sensitivity coefficients of strain gages with respect to the normal mode of blade vibrations, and it is implemented in Visual Fortran 6.0 macros and adapted to work with a finite element analysis software. The effectiveness of the proposed method is demonstrated through the example of developing a strain gage layout for a turbine blade made of a monocrystalline alloy with anisotropic properties.

Keywords: gas turbine engine, turbine blade, dynamic stresses, test, strain gage, optimization

Pivovarova M.V., Nihamkin M. Sh.