Papers by Keyword: Turbine Blade

Abstract: Heat resistant coatings are considered for the external surface Low-Pressure Steam Turbines (LPST). 410 stainless steel covered with nano heat resistant coatings consists of a heat resistant connecting layer enhanced by nanoparticles. A commercial paint was modified by using 20%wt of (titanium dioxide (TiO₂) - aluminum oxide (Al₂O₃)) with different concentrations range (25,50,75wt% of TiO₂) layers. These nano-coatings paints were airbrushed onto the surface of specimens of steam turbine blades. The test rig and experimental apparatus have been fabricated and collected to accomplish the thermal tests. The samples were subjected to heat resistance and a temperature test approximately similar to the steam turbine's operation condition temperature. The test results are used to choose the nano-coating layer with a concentration that ensures a composition's highest protective properties. The test sample with concentration (paint-(75% Al₂O₃+25% TiO₂)) showed the highest thermal properties compares with the other cases.

Abstract: Investigations of the rheological properties and the formation of the structure of stainless steel were performed. A computer model of the process of hammer forging of the turbine blades made of stainless steel 1.3 m long in the package Deform-3D was developed , with the help of which the necessary coefficients and parameters are determined to ensure maximum convergence of the calculated and experimental process data. The obtained data were used to create a mathematical model for stamping a large-sized turbine blade made of stainless steel with a length of 2.1 m. Mathematical modeling of the processes of stamping and distorting of a large-sized blade in the software package Deform-3D has been performed. The influence of process parameters on the stress-strain state (SSS), forming, temperature field in the forging at various stages of stamping. Determined temperature and deformation modes of stamping, the need for additional heating and optimal forgings geometry by stamping.

Abstract: The durability airworthiness verification of turbine blade is one key issue in the process of certifying a type certificate for the aircraft engine. This paper summarizes the limiting factors for turbine blade durability and proposes a compliance method to evaluate the durability life of turbine blade. The typical standards of blade durability were selected and evolution history of the regulations was traced. The regulation contents and differences between CCAR-33 and CS-E were analyzed. A series of compliance methods in airworthiness verification process were discussed in detail. Furthermore, an experimental compliance methodology was proposed to estimate the durability life of turbine blade, considering the damage of creep and fatigue. The novel methodology was verified using the scanning electron microscope (SEM) analysis. These efforts are of great benefit to support the process of obtaining the final type certificate.

Abstract: In order to improve the composition and microstructure of nickel-base single crystal superalloys, equilibrium phases of third generation single crystal superalloys RenéN6 and CMSX-10 have been researched by using thermodynamic calculation software JMatPro. The calculated results indicated that the two superalloys have the same equilibrium phases, such as liquid phase, γ phase, γ’ phase and TCP (topologically close-packed phases), however, there are differences in the quantity and temperature range. RenéN6 alloy has higher content of μ phase. And CMSX-10 alloy has higher γ’ phase precipitation temperature and more γ’ phase precipitates.

Abstract: With the development of aero-engine with high specific flux, high thrus-weight ratio, and high turbine inlet temperature, it is an effective way to improve the cooling efficiency by designing dense gas film holes on the blade surface of the turbine blades, especially at the intake side. However, the introduction of gas film holes destroys the geometrical integrity of the blade structure, resulting in a multiaxial high stress state of the blade material around the small holes, which seriously affects the strength and life of the cooling blades. In addition, the geometry design of the gas film holes also directly affects the temperature and the oxidation rate of the turbine rotor blades. In this paper, the researches on the mechanical properties and oxidative damage of the gas film holes at home and abroad in recent years have been systematically introduced. The effects of gas film holes on the durability and fatigue properties, the high temperature oxidation behavior of single crystal superalloys, and the thin-walled effect of oxidative damage of gas film holes have been systematically described.

Abstract: In order to improve the cooling effectiveness of the film, a numerical study was conducted to study the effects of different film-cooled angles on surface heat transfer. In this work CFD simulation has revealed the difference of injection angles ranging from 35°,45°,55°,65° and 90° with different blowing, where the low blowing ratios are represented by M = 0.5, and the high blowing ratios by M = 1.0 and 1.5. And the turbulence closure is done with the help of the k - ω shear stress transport (SST) turbulence model. It is found that the stream-wise variations in the angles of the holes do not really provide a significant change in the adiabatic film cooling effectiveness results. On the other hand, the results indicate that the hole of angles 35°and 45° improved the centerline and laterally averaged adiabatic effectiveness, and the effectiveness decrease particularly at high blowing ratios.

Abstract: Film cooling is vital for gas turbine blades to protect them from thermal stresses and high temperatures due to the hot gas flow in the blade surface. Film cooling is applied to almost all external surfaces associated with aerodynamic profiles that are exposed to hot combustion gases such as main bodies, end-walls, blade tips and leading edges. In a review of the literature, it was found that there are strong effects of free-stream turbulence, surface curvature and hole shape on film cooling performance also blowing ratio. The performance of the film cooling is difficult to predict due to the inherent complex flow fields along the surfaces of the airfoil components in the turbine engines. From all what we introducing the film cooling is reviewed through a discussion of the analyses methodologies, a physical description, and the various influences on film-cooling performance. Initially Computational analysis was done on a flat plate with hole inclined at 55° to the surface plate. This study focuses on the efficient computation of film cooling flows with three blowing ratio. The numerical results show the effectiveness cooling and heat transfer behavior with increasing injection blowing ratio M (0.5, 1, and 1.5). The influence of increased blade film cooling can be assessed via the values of Nusselt number in terms of reduced heat transfer to the blade. Predictions of film effectiveness are compared with experimental results for a circular jet at blowing ratios ranging from 0.5, 1.0 and 1.5. The present results are obtained at a free stream turbulence of 10%, which are the typical conditions upstream of the effectiveness is generally lower for a large stream-wise angle of 55°.

Abstract: The article presents a study of a turbine blade profile and roughness measurement processes - the task facing any manufacturer of this part. The blade is one of the most complex regarding parts manufacture because of its complex profile. This profile should be measured in several sections on the feather on all profile elements - the suction side, pressure surface, leading and trailing edge of a blade. If the blade has a shroud platform, its profile should be also measured (and possibly the gland packing profile). It is also necessary to measure the feather end and base of blade profile. Finally, a separate independent task is the blade tang profile measurement.

Abstract: The main causes of the damage of a compressor’s turbine blade are documented and described in the article. The turbine blade was made from titanium alloy grade 5 (VT6, Ti-6Al-4V). The analysed segments of the turbine blade were damaged by corrosion and erosion. The sample from the damaged blade was compared with an undamaged reference sample. The observed substantial distinctions between microstructure of the damaged and the reference sample were found using of light and scanning electron microscopy. The observed distinctions of the microstructure were caused by the differences in the heat treatment process.

Abstract: This paper presents flexural properties related to vibration behavior of jute reinforced polyester composite. The goal of the research is to seek green composite material that exhibits good strength and flexural properties along with good damping property designed for wind turbine blades. The material for reinforcement in the present study is jute fiber. The material for matrix is polyester resin. Glass and carbon fiber are used for hybridization. Specimens were fabricated by vacuum infusion technique. Laminates were constructed by stacking jute fiber clothes. Hybrid laminates were fabricated by stacking jute clothes covered by one ply glass cloth and jute clothes covered by one ply carbon cloth. Static flexural and free vibration tests were carried out to obtain the elastic modulus and vibration behavior of specimens, respectively. The result shows that the configuration of jute fiber cloth and glass fiber hybridized laminates possesses compromised properties between flexural properties and damping ratio.