Abstract.A study of the strength and deformation properties of freshwater ice under compression, tension and shear in a wide range of strain rates (10 −4 − 3 · 10 3 s −1 ) and temperatures of −5 • C, −20 • C, −40 • C and −60 • C was performed. Static stressstrain curves of ice under compression were obtained on which the identified strength properties of ice as well as compressive modulus. To determine the mechanical properties of ice at high-speed loading the Kolsky method was used with various embodiments of split Hopkinson bar. The deformation curves were obtained at various loading conditions. Thereon breaking points were defined as well as their dependence on the strain rate and temperature. Also static and dynamic strength properties of ice at splitting and circular shear were defined. Increase in the dynamic strength properties upon the static ones for all loading conditions was marked.

This paper reports the results from numerical simulations of the turbine blade cooling air delivery system performance using commercial CFD code Ansys CFX v11. Computations have been performed with variation of pre-swirl nozzle location radius, rotor-rotor rotating cavity width and the way of air transmission through the cover-plate. There are two ways of air transmission depending on the cover-plate design: through the CAO (circular array of orifices) or CAS (continuous annular slot). Computations are performed within the parameter range similar to gas-turbine engine operating conditions: 0.375<λT<0.98; 0.548<β0<2.5; 1.69·107<Reφ<2.33·107; 2.79·105<Cw<5.73·105. It has been shown that the selection of optimum radius of pre-swirl nozzle location is determined by different factors and depends on design and boundary conditions. The rotor-rotor rotating cavity width does not affect delivery system performances and is selected by a designer based on the constructional necessity, strength, weight and dynamic behavior of the turbine rotor. Rotating orifices reduce the swirl ratio βb before the blade cooling rim slot reduce adiabatic effectiveness Θ and increase loss coefficient ζ.

Constant rise of hot gas temperature is crucial for the creation of modern gas-turbines engines requiring considerable improvement of cooling configurations. A high pressure turbine blade is one of the most crucial and loaded details in gas-turbine engines. A HPT blade is affected by different operational deviations: stochastic fluctuations of inlet parameters and difference in operational parameters for manufactured engines. Combination of these factors makes the task of uncertainty quantification and robust optimization of the HPT blade relevant in modern science. The authors make an attempt to implement robust optimization to the HPT blade of the gas-turbine engine. The two most important areas of the cooling blade (the leading edge (LE) and the blade tip) were taken into account. The operational and the aleatoric uncertainties were analyzed. These uncertainties represent the fluctuations in the operational parameters and the random-unknown conditions such as the boundary values and or geometrical variations. Industrial HPT blade with a serpentary cooling system and film cooling at the LE was considered. Results of many engine tests were applied to construct probability density function distributions for operational uncertainties. More than 100 real gas-turbines were examined. The following operational uncertainties were reviewed: inlet hot gas pressure and temperature together with cooling air pressure. The tip gap was used as geometrical variation. Conjugate Heat Transfer computations were carried out for the temperature distribution obtained. Geometrical variations of the LE film cooling rows and the tip gap are variables in the robust optimization process. The authors developed a special technology for full parameterization of the LE film-cooling rows only by two parameters. A surrogate model technique (the response surface and the Monte-Carlo method) was applied for the uncertainty quantification and the robust optimization processes. The IOSO technology was employed as one of the robust optimization tools. This technology is also based on the widespread application of the response surface technique. Robust optimal solution (the Pareto set) between cooling effectiveness of the leading edge and the blade tip and aerodynamic efficiency was obtained as the result. At chosen point from the Pareto set (angle point) we calculated necessary levels of robust criteria characterized LE and blade tip cooling effectiveness and kinetic energy losses.

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The layer of non-impregnated aramid fibers is widely used in the containment systems of aircraft gas turbine engines. Such systems are found to be especially cost-effective and light weight for mitigating engine debris during a fan blade-out event. This is mostly because non-impregnated aramid fibers have a high strength per unit weight. Moreover, it is inexpensive to manufacture such a containment system compared to traditional metallic systems. To properly utilize this advantage, it is necessary to have a finite element (FE) analysis modeling methodology for daily design tasks. Non-impregnated aramid fibers winding for fan case modeling for engine containment systems is a difficult task. This research implied both experimental and modeling techniques, and data characterizing the behavior of fabric materials for engine containment systems. This research was aimed at addressing engine containment modeling issues. Thus this work has resulted in the following major accomplishments: • Experimental Characterization of Non-impregnated Aramid Fibers: the fabric material model originally was created during this phase. The independent laboratory tests conducted at NPO Saturn form the basis of this model. These material models are general enough to be used as the constitutive model for both static and dynamic/explicit FE analyses. • Static Ring Tests: Static tests of containment wraps subjected to loads through a blunt nose impactor were performed at NPO Saturn. Ballistic tests of containment wraps subjected to a high-velocity projectile were performed at NPO Saturn. These tests provided the test cases (the benchmark results) to validate the developed FE methodology. • FE Material Model Development: The material models were used by the research team in the FE simulation of static and ballistic tests. The static test results have been validated by NPO Saturn using the ANSYS FE program. The ballistic test results were validated by NPO Saturn using the LS-DYNA FE program. • Engine Fan Blade-Out (FBO) Simulation: The knowledge gained from previous tasks was used by NPO Saturn for the the numerical simulation of real engine FBO events involving the existing production engine models and compared to the test results (employing thelayer of non-impregnated aramid fibers containment). • Combined Fan and Metal Case Comparison: The relative comparison between the non-impregnated aramid fibers and the metal materials in engine FBO containment systems has been carried out in order to ascertain that the non-impregnated aramid fibers case is more advantageous.