Damping Estimation for Turbine Blades Under Non-stationary Rotation Speed

2015 ◽  
pp. 145-152
Author(s):  
Luigi Carassale ◽  
Michela Marrè-Brunenghi ◽  
Stefano Patrone
Keyword(s):  
Rotation Speed ◽  
Turbine Blades ◽  
Stationary Rotation ◽  
Damping Estimation

Estimation of Damping for Turbine Blades in Non-Stationary Working Conditions

2015 ◽  
Author(s):  
Luigi Carassale ◽  
Michela Marrè-Brunenghi ◽  
Stefano Patrone
Keyword(s):  
Power Plants ◽  
Rotation Speed ◽  
Thermal Power ◽  
Turbine Blades ◽  
Experimental Tests ◽  
Strain Gauges ◽  
Identification Procedure ◽  
Time Frequency ◽  
Run Up ◽  
Critical Components

Turbine blades are critical components in thermal power plants and their design process usually includes experimental tests in order to tune or confirm numerical analyses. These tests are generally carried out on full-scale rotors having some blades instrumented with strain gauges and usually involve a run-up and/or a run-down phase. The quantification of damping in these conditions is rather complicated, since the finite sweep velocity produces a distortion of the vibration amplitude in contrast to the Frequency-Response Function that would be expected for an infinitely slow crossing of the resonance. In this work, we show through a numerical simulation that the usual identification procedures lead to a systematic overestimation of damping due both to the finite sweep velocity, as well as to the variation of the blade natural frequency with the rotation speed. An identification procedure based on the time-frequency analysis is proposed and validated through numerical simulations.

Retracted: Prediction and optimization of volumetric power draw in an aerated and stirred vessel used in wastewater biological plant: a mathematical model developed by using central composite rotatable design analysis (CCRD)

2016 ◽  
Vol 11 (3) ◽  
pp. 590-600
Author(s):  
Hayder Mohammed Issa
Keyword(s):  
Mathematical Model ◽  
Rotation Speed ◽  
Turbine Blades ◽  
Central Composite Rotatable Design ◽  
Stirred Vessel ◽  
Stirred Vessels ◽  
Power Draw ◽  
Independent Parameters ◽  
Central Composite ◽  
Rotatable Design

In this study, the volumetric power draw P/V was determined as a factor in designing and identifying the optimal condition a successful aeration for stirred wastewater biological treatment vessels. The study was performed to characterize the volumetric power draw in the aerated stirred vessels by optimizing the operation variables. The concerning factors were improved by conjugating stirring and aeration with efficient and economic volumetric power draw condition. The drawn volumetric power was tested and analyzed for three independent parameters; impellers rotation speed (100–200 rpm), turbine blades submergence ratio S/W (0.33–1.67) and wastewater height level ratio H/D (1.37–1.58). A mathematical model was developed in the form of a nonlinear polynomial mathematical model to predict the P/V. The optimal values of the P/V and of relevant parameters were computed through the application of the Box–Wilson technique by application of the central composite rotatable design (CCRD) model. The volumetric power draw P/V and the relevant independent parameters are presented in optimal conditions surface plots that obtained from the nonlinear mathematical model. Optimum analysis result for the independent parameters showed low levels of impellers rotation speed and turbine submergence ratio draw lower P/V while wastewater height did not have a clear effect on P/V.

scholarly journals Some Developments on Cup Anemometer Aerodynamics

2014 ◽  
Vol 348 ◽  
pp. 179-185 ◽  
Author(s):  
Santiago Pindado ◽  
Javier Cubas
Keyword(s):  
Transfer Function ◽  
Rotation Speed ◽  
The Other ◽  
Stationary Rotation ◽  
Other Hand ◽  
The One ◽  
Cup Anemometer

In the present study the geometry of cups is experimentally studied through anemometer performance. This performance is analyzed in two different ways. On the one hand the anemometer transfer function between cases is compared. On the other hand the stationary rotation speed is decomposed into constant and harmonic terms, the comparison being established between the last ones. Results indicate that some cup shapes can improve the uniformity of anemometer rotation, this fact being important to reduce degradation due to ageing.

Chemical partitioning of elements in Ni-base MC-carbide reinforced eutetic superalloys

1983 ◽  
Vol 41 ◽  
pp. 250-251
Author(s):  
E. F. Koch ◽  
E. L. Hall ◽  
S. W. Yang
Keyword(s):  
Alloy Composition ◽  
Volume Fraction ◽  
Lattice Mismatch ◽  
Turbine Blades ◽  
Eutectic Alloys ◽  
Alloy Matrix ◽  
X Ray ◽  
Gas Turbine Blades ◽  
Analytical Electron ◽  
Analytical Electron Microscope

The plane-front solidified eutectic alloys consisting of aligned tantalum monocarbide fibers in a nickel alloy matrix are currently under consideration for future aircraft and gas turbine blades. The MC fibers provide exceptional strength at high temperatures. In these alloys, the Ni matrix is strengthened by the precipitation of the coherent γ' phase (ordered L12 structure, nominally Ni3Al). The mechanical strength of these materials can be sensitively affected by overall alloy composition, and these strength variations can be due to several factors, including changes in solid solution strength of the γ matrix, changes in they γ' size or morphology, changes in the γ-γ' lattice mismatch or interfacial energy, or changes in the MC morphology, volume fraction, thermal stability, and stoichiometry. In order to differentiate between these various mechanisms, it is necessary to determine the partitioning of elemental additions between the γ,γ', and MC phases. This paper describes the results of such a study using energy dispersive X-ray spectroscopy in the analytical electron microscope.

Selection of a leading edge noise prediction method for PNoise

2018 ◽  
pp. 214-223
Author(s):  
AM Faria ◽  
MM Pimenta ◽  
JY Saab Jr. ◽  
S Rodriguez
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
Prediction Method ◽  
Leading Edge ◽  
Wind Farms ◽  
Broadband Noise ◽  
Turbulence Energy ◽  
Noise Prediction ◽  
Migration Routes ◽  
Turbulent Inflow

Wind energy expansion is worldwide followed by various limitations, i.e. land availability, the NIMBY (not in my backyard) attitude, interference on birds migration routes and so on. This undeniable expansion is pushing wind farms near populated areas throughout the years, where noise regulation is more stringent. That demands solutions for the wind turbine (WT) industry, in order to produce quieter WT units. Focusing in the subject of airfoil noise prediction, it can help the assessment and design of quieter wind turbine blades. Considering the airfoil noise as a composition of many sound sources, and in light of the fact that the main noise production mechanisms are the airfoil self-noise and the turbulent inflow (TI) noise, this work is concentrated on the latter. TI noise is classified as an interaction noise, produced by the turbulent inflow, incident on the airfoil leading edge (LE). Theoretical and semi-empirical methods for the TI noise prediction are already available, based on Amiet’s broadband noise theory. Analysis of many TI noise prediction methods is provided by this work in the literature review, as well as the turbulence energy spectrum modeling. This is then followed by comparison of the most reliable TI noise methodologies, qualitatively and quantitatively, with the error estimation, compared to the Ffowcs Williams-Hawkings solution for computational aeroacoustics. Basis for integration of airfoil inflow noise prediction into a wind turbine noise prediction code is the final goal of this work.

An appraisal of characteristic mechanical properties and microstructure of friction stir welding for Aluminium 6061 alloy – Silicon Carbide (SiCp) metal matrix composite

2019 ◽  
Vol 13 (4) ◽  
pp. 5804-5817
Author(s):  
Ibrahim Sabry
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Metal Matrix Composite ◽  
Matrix Composite ◽  
Metal Matrix ◽  
Welded Joint ◽  
Rotation Speed ◽  
Fusion Welding ◽  
Friction Stir ◽  
Al 6061

It is expected that the demand for Metal Matrix Composite (MMCs) will increase in these applications in the aerospace and automotive industries sectors, strengthened AMC has different advantages over monolithic aluminium alloy as it has characteristics between matrix metal and reinforcement particles.  However, adequate joining technique, which is important for structural materials, has not been established for (MMCs) yet. Conventional fusion welding is difficult because of the irregular redistribution or reinforcement particles.  Also, the reaction between reinforcement particles and aluminium matrix as weld defects such as porosity in the fusion zone make fusion welding more difficult. The aim of this work was to show friction stir welding (FSW) feasibility for entering Al 6061/5 to Al 6061/18 wt. % SiCp composites has been produced by using stir casting technique. SiCp is added as reinforcement in to Aluminium alloy (Al 6061) for preparing metal matrix composite. This method is less expensive and very effective. Different rotational speeds,1000 and 1800 rpm and traverse speed 10 mm \ min was examined. Specimen composite plates having thick 10 mm were FS welded successfully. A high-speed steel (HSS) cylindrical instrument with conical pin form was used for FSW. The outcome revealed that the ultimate tensile strength of the welded joint (Al 6061/18 wt. %) was 195 MPa at rotation speed 1800 rpm, the outcome revealed that the ultimate tensile strength of the welded joint (Al 6061/18 wt.%) was 165 MPa at rotation speed 1000 rpm, that was very near to the composite matrix as-cast strength. The research of microstructure showed the reason for increased joint strength and microhardness. The microstructural study showed the reason (4 %) for higher joint strength and microhardness.  due to Significant   of SiCp close to the boundary of the dynamically recrystallized and thermo mechanically affected zone (TMAZ) was observed through rotation speed 1800 rpm. The friction stir welded ultimate tensile strength Decreases as the volume fraction increases of SiCp (18 wt.%).

Experiments of Wind Turbine Blades with Rocket Triggered Lightning

2009 ◽  
Vol 129 (5) ◽  
pp. 689-695
Author(s):  
Masayuki Minowa ◽  
Shinichi Sumi ◽  
Masayasu Minami ◽  
Kenji Horii
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
Wind Turbine Blades ◽  
Triggered Lightning
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