Авіаційно-космічна техніка та технологія (Aug 2019)
DESIGN-EXPERIMENTAL TECHNIQUE FOR DETERMINING A DYNAMIC MODEL OF ELASTICITY OF PRODUCED SEALING COATINGS OF GTE TURBINES
Abstract
The aim of the work was the development and testing of a method for determining the dynamic modulus of elasticity of running-in sealing gasket coatings for GTE turbines. Many contradictory requirements are put forward to these coatings, therefore, to satisfy them, it was proposed to apply coatings with variable properties at various stages of the life cycle of gas turbine engines. However, the development of new coatings requires a variety of mechanical tests, including to evaluate the dynamic modulus of elasticity. The porous structure and, accordingly, the low strength of the developed coatings do not allow the use of standard methods for the evaluation of mechanical properties, so there is a need to develop a special method for determining the elastic modulus. In the course of the study, the finite element method, statistical methods, experimental methods for determining the natural frequency of oscillations were applied. Investigations were carried out for running-in sealing coating of the stator of turbines of gas turbine engines KNA-82 + CoNiCrAlY. The numerical experiment was performed in the Ansys Work-bench 2019 R2 software package. Since coatings are used at elevated temperatures, it was necessary to estimate the modulus of elasticity at various temperatures, which required additional studies of temperature-dependent properties that affect the desired value. As a result of the implementation of the plan of a numerical experiment to determine the frequency of natural oscillations of samples with a coating while varying its elastic modulus and temperature, as well as solving the inverse problem of establishing the dependence of the dynamic elastic modulus on the natural oscillation frequency of a coated sample, we developed a calculation and experimental method for determining the dynamic modulus elasticity of running-in sealing coatings of GTE turbines. The developed technique is used to determine the dynamic modulus of elasticity of running-in coatings of different chemical composition and structure in the range of operating temperatures, which can be used to optimize their composition, structure, and properties.
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