Papers by Keyword: Compressor Blade

Abstract: This work presents results of the experimental fatigue analysis of the compressor blades. In the investigations the blade with the V-notch (which simulates the foreign object damage) was considered. The notch was created by machining. The blades during the fatigue test were entered into transverse vibration. The crack propagation process was conducted in resonance conditions. During investigations both the amplitude of the blade tip displacement and also the crack length were monitored. As the results of presented investigations both the number of load cycles to crack initiation and also the crack growth dynamics in the compressor blade subjected to resonant vibrations were determined. In the work the influence of crack size on the resonant frequency was also investigated.

Abstract: The compressor blade is the key components of the aero-engine to seriously impact the air dynamic performance. However, components with complex designs specifications might pose manufacturing challenges especially when finishing processes are needed to enable their compliance with tight industrial standards for workpiece surface integrity. Information on polishing processes for such sensitive industrial applications is scarce. The paper reports on the influence of polishing methods on the surface integrity of compressor blade obtained after different polishing methods. The research focuses on identifying an “optimised” polishing method for different area that will enable finishing the compressor blade. Two (belt; bob) polishing methods have been tested to address the overall finishing of compressor blade. Although significant differences in tool life performance exist between belt and bob polishing methods, both are capable to meet the requirements of minimum workpiece surface coverage if “optimised” operating parameters are employed. This is proved that belt and bob polishing methods can be employed to enable automated overall finishing of compressor blade.

Abstract: Gas turbine compressor blades will age and degrade in their operation. There are a lot of factors that will contribute to the degradation mechanisms and its acceleration. These factors encompass the site location, the site conditions including the aspect of air quality, water washing practice, etc. A study undertaken by Materials Engineering Group of TNB Research Sdn Bhd on 2 units of gas turbine compressor those are located near to the sea around Peninsular of Malaysia, to determine the degradation mechanisms of the blades. All these gas turbine units are located in different industrial environment. The first gas turbine unit, so called GTA is located in coastal, petrochemicals production and crude oil refining environment. The second gas turbine unit, so called GTB, located in coastal and industrial environment. The surrounding industries of GTB including oil refinery, chemical, ship fabrication and etc. This paper reports the degradation type of those gas turbine units’ compressor blades with their contributing factors.

Abstract: This paper presents results of experimental fatigue analysis of the compressor blades subjected to high cycle fatigue. The blades used in investigations were preliminary defected to simulate the foreign object damage. The blades during experiment were entered into transverse vibration. In results of investigations, the number of cycles to crack initiation and also the crack growth rate were obtained for the blade subjected to transverse vibrations. Moreover, observations of the beach marks on the blade fractures revealed two main shemes of crack propagation process. In this work, the finite element stress analysis of the blade was also performed. Obtrained numerical results shoved that stress level in the notch vicinity is 3 times higher than the stress in the blade without mechanical defects.

Abstract: This paper presents results of numerical crack propagation analysis of the compressor blades subjected to transverse vibrations. For stress intensity factor calculation in the half-elliptical crack, a dual boundary element method was used. In this analysis the automated remeshing procedure was used for creation of numerical models with a different crack size. Obtained results of numerical calculations were compared to results of experimental investigations performed for PZL-10W engine compressor blades tested in resonance conditions.

Abstract: A simulation method for fluid-structure interaction (FSI) in compressor blades was discussed to predict the aeroelastic stability of blades. Using the MFX, which is a Multi-Field Solver in ANSYS, the total force of computational fluid dynamics (CFD) have been interpolated to computational structural dynamics (CSD) grids, and then the vibration displacements of CSD nodes have been interpolated to CFD grids at the blade surface. In CFD analysis, the grid coordinates of the moveable region have been updated by multi-layer moving grid technique, and the finite volume method has been applied to calculate the Reynolds-averaged Navier-Stokes (RANS) equations closed by k-E turbulent model. For NASA Rotor 67, detect the displacement response of compressor blades at the design speed , and the aeroelastic stability of blades has been analyzed preliminarily. The study shows that the FSI procedure is feasible to predict the aeroelastic stability of compressor blades.

Abstract: To describe the frequency distribution of the rotor blades and improve the optimization, resonance reliability of the rotor blades was analyzed in this paper. Considering the variety of rand-om variables, we jointly used finite element method and response surface method. The Campbell diagram was set up to describe blade resonance by analyzing the compressor rotor blade vibration characteristics. For the second-order vibration failure of the rotor blade, we considered the impact of random variables with the rotor blade material, the blade dimension and the rotor speed. The pro-bability distribution and allowable reliability of the second-order vibration frequency was calculated, and the sensitivity of the random variables influencing vibration frequency was completed. The res-ults show that the resonance reliability with the confidence level 0.95 of the rotor blade are = 0.99753 with the excited order =4 and =0.99767 with the excited order =5,and basically ag-ree with the design requirements when the rotor speed =9916.2, and the factors mainly affe-cting the distribution of the second-order vibration frequency of the blades include elastic modulus, density and the rotor speed, with the sensitivity probabilities 35.09%,34.56% and 24.15% respecti-vely.

Abstract: The article describes a series of experiments and calculations for verification high-speed deformation behavior and fracture models for the titanium alloy Ti-6Al-4V. Samples made of the micro-and nanocrystalline structure alloy Ti-6Al-4V were ballistically damaged in conditions that meet a ballistic damage of real turbine engine fan blades. It is found that the behavior of the microcrystalline alloy is more accurately described by the Johnson-Cook model. In the case of nanocrystalline material the best fit is achieved by using the Cooper-Symonds model. The achieved models parameters are presented.

Abstract: A successful prediction that whether a compressor blade is able to overcome the resonance fatigue and fatigue life of forced vibration is based on its harmonic response analysis.Hard coatings with metal or ceramic substrate are effective to change the natural characteristics and vibration amplitude of a compressor blade so that to improve the anti-vibration fatigue capability. In this paper, modal analysis and harmonic response analysis based on the finite element method are achieved to investigate the contributions of the two different hard coatings on the natural characteristics and vibration amplitude of a compressor blade. The two kinds of hard coatings are modeled by both anisotropic materials and involving their piezoelectric or piezomagnetic effects. The blade is modeled as an isotropic one. The natural frequencies and vibration amplitude of blade with different coating thickness are numerically calculated and compared. Results show that the hard coatings with different thickness play an important role in the natural characteristics and harmonic response analysis of the blade.

Abstract: The superalloy of Inconel 718 variety is widely used to produce compressor blade in gas turbine engine. The blade tip invariably wears in services and thus requires frequent metallization for repairing. In most commercial Turbine Engine Industries the metallised blades, after grinding, undergo a stress relieving heat treatment at 7600C before return for applications. In this study, the metallised blade is heat treated at different conditions and compared its microstructure and hardness with those of the standard stress relieving treatment blades used in most industries. The microstructure of the stress relieving sample contains dendrite with hardness of 230 HV for the melt zone, 190 HV for the Heat Affected Zone (HAZ) and 420 HV for the parent metal. Solutionising at 982 or 10660C developed hardness less than 220 HV in all sections. By long time ageing treatment of the solutionised sample developed high hardness across the whole blade. These treatments homogenized the microstructure and produced high hardness values by precipitation of secondary phase structures across the blade.