On the Probabilistic Endurance Prediction Approach for Turbomachinery Blades and Vanes

2020 ◽  
Author(s):  
Davendu Y. Kulkarni ◽  
Caetano Peng
Keyword(s):  
Robust Design ◽  
Product Life Cycle ◽  
Operating Conditions ◽  
Rotor Blades ◽  
Probabilistic Methods ◽  
Wide Range ◽  
Deterministic Methods ◽  
Stator Vane ◽  
Turbomachinery Blades ◽  
Prediction Approach

Abstract The design and aeromechanical assessment of turbomachinery blades and vanes comprises a wide range of complex processes that tend to be based on conventional deterministic methods. These processes often provide a ‘snapshot’ evaluation of the new component designs at the nominal operating conditions. While the deterministic methods can predict the high cycle fatigue (HCF) endurance with reasonable accuracy; they assume that the conservative safety factors applied to cover for the parametric variations, uncertainties and unknowns will not change during the product life cycle. This approach is intended to be conservative and in some cases may overlook the lack of robustness. The present paper proposes a robust design analysis approach based on probabilistic methodology for the aeromechanical assessment of rotor blades and stator vanes of turbomachinery. The robust design approach can account explicitly for the effects of design and manufacturing variability. This methodology can reduce the levels of conservatism in the deterministic approach and can provide a more thorough risk assessment. This paper offers a generalised aeromechanical analysis formulation based on probabilistic methods to evaluate the HCF capability of turbomachinery components. Herein, this methodology is demonstrated by using a typical stator vane of an aero engine compressor and it is based on Monte-Carlo and DOE simulations. The methodology consists of parametric sensitivity studies and identification of the most influential parameters that control the HCF endurance. Future ideas and roadmap of the aeromechanical probabilistic analysis capability development are also discussed.

scholarly journals Composite UHBR Fan for Forced Response and Flutter Investigations

2021 ◽  
Author(s):  
Torben Eggers ◽  
Jens Friedrichs ◽  
Jan Goessling ◽  
Joerg R. Seume ◽  
Nunzio Natale ◽  
...  
Keyword(s):  
Forced Response ◽  
Operating Conditions ◽  
Rotor Blades ◽  
Future Research ◽  
Test Case ◽  
Composite Blade ◽  
Wide Range ◽  
Open Test ◽  
Performance Specifications ◽  
Transonic Fan

Abstract In the CA3ViAR (Composite fan Aerodynamic, Aeroelastic, and Aeroacoustic Validation Rig) project, a composite low-transonic fan is designed and tested. The aim is a scaled ultra-high bypass ratio (UHBR) fan with state-of-the-art aerodynamic performance and composite rotor blades, which features aeroelastic phenomena, e.g. forced response by inlet distortions and flutter, under certain operating points within the wind tunnel. In this paper, the aerodynamic and aeroelastic design process starting from the overall performance specifications to a threedimensional numerical model is described. A target of eigen-frequency and twist-to-plunge ratio is specified such that flutter occurs at desired operating conditions with a sufficient margin with respect to the working line. Different materials and layups of the composite blade are analyzed to reach the structural target. The fan should serve as an open test case to advance the future research on aerodynamic, aeroelastic, and aeroacoustic performance investigations in a wide range of operating conditions. A preliminary fan stage design is presented in this paper.

Wake Induced Time-Variant Aerodynamics Including Rotor-Stator Axial Spacing Effects

1981 ◽  
Vol 103 (1) ◽  
pp. 59-66 ◽  
Author(s):  
S. Fleeter ◽  
R. L. Jay ◽  
W. A. Bennett
Keyword(s):  
Large Scale ◽  
Primary Source ◽  
Forced Response ◽  
Operating Conditions ◽  
Rotor Blades ◽  
Experimental Program ◽  
Axial Distance ◽  
Spacing Effects ◽  
Spacing Ratio ◽  
Wide Range

The overall objective of this experimental program was to quantify the effects of rotor-stator axial spacing on the fundamental time-variant aerodynamics relevant to forced response in turbomachinery. This was accomplished in a large-scale, low-speed, single-stage research compressor which permitted two rotor-stator axial spacing ratios representative of those found in advanced design compressors to be investigated. At each value of the axial spacing ratio, the aerodynamically induced fluctuating surface pressure distributions on the downstream vane row, with the primary source of excitation being the upstream rotor wakes, were measured over a wide range of compressor operating conditions. The velocity fluctuations created by the passage of the rotor blades were measured in the nonrotating coordinate system. Data obtained described the variation of the rotor wake with both loading and axial distance from the rotor as parameters. These data also served as a reference in the analysis of the resulting time-variant pressure signals on the vane surfaces.

A Modified Beddoes–Leishman Model for Unsteady Aerodynamic Blade Load Computations on Wind Turbine Blades

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Moutaz Elgammi ◽  
Tonio Sant
Keyword(s):  
Flow Separation ◽  
Random Noise ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Wind Tunnel Test ◽  
Operating Conditions ◽  
Rotor Blades ◽  
Unsteady Aerodynamic ◽  
Novel Approach ◽  
Wide Range

A modified version of the Beddoes–Leishman (B-L) dynamic stall model is presented. A novel approach was applied for deriving the effective flow separation points using two-dimensional (2D) static wind tunnel test data in conjunction with Kirchhoff's model. The results were then fitted in a least-squares sense using a new nonlinear model that gives a better fit for the effective flow separation point under a wide range of operating conditions with fewer curve fitting coefficients. Another model, based on random noise generation, was also integrated within the B-L model to simulate the effects of vortex shedding more realistically. The modified B-L model was validated using 2D experimental data for the S809 and NACA 4415 aerofoils under both steady and unsteady (oscillating) conditions. The model was later embedded in a free-wake vortex model to estimate the unsteady aerodynamic loads on the NREL Phase VI rotor blades consisting of S809 aerofoils when operating under yawed rotor conditions. The results in this study confirm the effectiveness of the proposed modifications to the B-L method under both 2D and three-dimensional (3D) (rotating) conditions.

Probabilistic Analysis of Radial Gear Compressors

2012 ◽  
Author(s):  
Thorsten van Lil ◽  
Matthias Voigt ◽  
Konrad Vogeler ◽  
Christian Wacker ◽  
Uwe Rockstroh
Keyword(s):  
Monte Carlo ◽  
Probabilistic Analysis ◽  
High Efficiency ◽  
Response Surfaces ◽  
Operating Conditions ◽  
Probabilistic Methods ◽  
Compression Process ◽  
Gear Design ◽  
Wide Range ◽  
Design Challenges

Integrally geared compressors offer a wide range of applications for probabilistic analysis. The combination of a multi shaft compressor with an integral gear under changing operating conditions creates a lot of design challenges. The gear design needs to meet the requirements of the compression process, like the rotating speed of the pinions or the pinion power. These requirements lead to a specific gear with its specific properties. The examination and verification of the internal correlations between thermodynamics and gear design is one significant objective of the project as a high efficiency of the compression process may be connected with high gear losses, or the other way around. These design challenges ought to be investigated with probabilistic methods, such as the Monte-Carlo-Simulation. With such methods, it is possible to explore a wide design space automatically in order to learn about correlations between probabilistic input and output parameters as well as in order to choose a better design. In a first step of this project, all process steps relevant for designing an integrally geared compressor have been combined to form one single automated algorithm. This algorithm is used for Monte-Carlo-Simulations (MCS) with optimal Latin-Hypercube as the sampling method. On the basis of the MCS results, response surfaces can be created to describe the scatter and the behaviour of the result parameters. Furthermore, response surfaces can be used as meta models for optimization and prediction. This paper seeks to address the use and the performance of response surfaces.

Shape Optimization of Transonic Compressor Blades Using Quasi-3D Flow Physics

2000 ◽  
Author(s):  
June Chung ◽  
Ki D. Lee
Keyword(s):  
Design Method ◽  
Computational Cost ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Rotor Blades ◽  
Navier Stokes ◽  
Compressor Blades ◽  
Transonic Compressor ◽  
Compressor Rotor ◽  
Wide Range

A design method for transonic compressor rotor blades is developed based on Navier-Stokes physics. The method is applied to optimize the blade sections at several span stations, and new three-dimensional blades are constructed by interpolating the geometry of the designed blade sections. The method is demonstrated with NASA Rotor 37, producing new rotor blades with improved adiabatic efficiency over a wide range of operating conditions. The results indicate that the developed design process can find improved designs at an affordable computational cost.

Comparison of Deterministic and Linear Cosine Spatial Filtering of Transmission Electron Micrographs

1972 ◽  
Vol 30 ◽  
pp. 596-597
Author(s):  
David A. Ansley
Keyword(s):  
Spherical Aberration ◽  
Focal Length ◽  
Chromatic Aberration ◽  
Spatial Filter ◽  
Operating Conditions ◽  
Objective Lens ◽  
List Type ◽  
Spatial Filters ◽  
Transmission Electron ◽  
Wide Range

The coherence of the electron flux of a transmission electron microscope (TEM) limits the direct application of deconvolution techniques which have been used successfully on unmanned spacecraft programs. The theory assumes noncoherent illumination. Deconvolution of a TEM micrograph will, therefore, in general produce spurious detail rather than improved resolution.A primary goal of our research is to study the performance of several types of linear spatial filters as a function of specimen contrast, phase, and coherence. We have, therefore, developed a one-dimensional analysis and plotting program to simulate a wide 'range of operating conditions of the TEM, including adjustment of the:(1) Specimen amplitude, phase, and separation(2) Illumination wavelength, half-angle, and tilt(3) Objective lens focal length and aperture width(4) Spherical aberration, defocus, and chromatic aberration focus shift(5) Detector gamma, additive, and multiplicative noise constants(6) Type of spatial filter: linear cosine, linear sine, or deterministic

Structure and properties of compact articles from high-alloyed iron powder with adding of boron nitride

2020 ◽  
pp. 39-48
Author(s):  
B. O. Bolshakov ◽  
◽  
R. F. Galiakbarov ◽  
A. M. Smyslov ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Boron Nitride ◽  
Grain Boundary ◽  
Bending Strength ◽  
Physical And Mechanical Properties ◽  
Operating Conditions ◽  
Structure And Properties ◽  
Steam Turbines ◽  
Friction Forces ◽  
Wide Range

The results of the research of structure and properties of a composite compact from 13 Cr – 2 Мо and BN powders depending on the concentration of boron nitride are provided. It is shown that adding boron nitride in an amount of more than 2% by weight of the charge mixture leads to the formation of extended grain boundary porosity and finely dispersed BN layers in the structure, which provides a high level of wearing properties of the material. The effect of boron nitride concentration on physical and mechanical properties is determined. It was found that the introduction of a small amount of BN (up to 2 % by weight) into the compacts leads to an increase in plasticity, bending strength, and toughness by reducing the friction forces between the metal powder particles during pressing and a more complete grain boundary diffusion process during sintering. The formation of a regulated structure-phase composition of powder compacts of 13 Cr – 2 Mо – BN when the content of boron nitride changes in them allows us to provide the specified physical and mechanical properties in a wide range. The obtained results of studies of the physical and mechanical characteristics of the developed material allow us to reasonably choose the necessary composition of the powder compact for sealing structures of the flow part of steam turbines, depending on their operating conditions.

Nitrogen Removal from Anaerobically-Treated Leachate

1984 ◽  
Vol 19 (1) ◽  
pp. 87-100
Author(s):  
D. Prasad ◽  
J.G. Henry ◽  
P. Elefsiniotis
Keyword(s):  
Nitrogen Removal ◽  
Air Flow ◽  
Operating Conditions ◽  
Air Flow Rate ◽  
Flow Rates ◽  
Anaerobic Filter ◽  
Ph Values ◽  
Wide Range ◽  
Ammonia Desorption ◽  
Effects Of Ph

Abstract Laboratory studies were conducted to demonstrate the effectiveness of diffused aeration for the removal of ammonia from the effluent of an anaerobic filter treating leachate. The effects of pH, temperature and air flow on the process were studied. The coefficient of desorption of ammonia, KD for the anaerobic filter effluent (TKN 75 mg/L with NH3-N 88%) was determined at pH values of 9, 10 and 11, temperatures of 10, 15, 20, 30 and 35°C, and air flow rates of 50, 120, and 190 cm3/sec/L. Results indicated that nitrogen removal from the effluent of anaerobic filters by ammonia desorption was feasible. Removals exceeding 90% were obtained with 8 hours aeration at pH of 10, a temperature of 20°C, and an air flow rate of 190 cm3/sec/L. Ammonia desorption coefficients, KD, determined at other temperatures and air flow rates can be used to predict ammonia removals under a wide range of operating conditions.

scholarly journals Applications of Biocatalysts for Sustainable Oxidation of Phenolic Pollutants: A Review

2021 ◽  
Vol 13 (15) ◽  
pp. 8620
Author(s):  
Sanaz Salehi ◽  
Kourosh Abdollahi ◽  
Reza Panahi ◽  
Nejat Rahmanian ◽  
Mozaffar Shakeri ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Operating Conditions ◽  
Phenolic Pollutants ◽  
Petroleum Refinery Wastewater ◽  
Start Up ◽  
Low Concentrations ◽  
Effective Removal ◽  
Wide Range ◽  
Loading Effects ◽  
Spent Caustic

Phenol and its derivatives are hazardous, teratogenic and mutagenic, and have gained significant attention in recent years due to their high toxicity even at low concentrations. Phenolic compounds appear in petroleum refinery wastewater from several sources, such as the neutralized spent caustic waste streams, the tank water drain, the desalter effluent and the production unit. Therefore, effective treatments of such wastewaters are crucial. Conventional techniques used to treat these wastewaters pose several drawbacks, such as incomplete or low efficient removal of phenols. Recently, biocatalysts have attracted much attention for the sustainable and effective removal of toxic chemicals like phenols from wastewaters. The advantages of biocatalytic processes over the conventional treatment methods are their ability to operate over a wide range of operating conditions, low consumption of oxidants, simpler process control, and no delays or shock loading effects associated with the start-up/shutdown of the plant. Among different biocatalysts, oxidoreductases (i.e., tyrosinase, laccase and horseradish peroxidase) are known as green catalysts with massive potentialities to sustainably tackle phenolic contaminants of high concerns. Such enzymes mainly catalyze the o-hydroxylation of a broad spectrum of environmentally related contaminants into their corresponding o-diphenols. This review covers the latest advancement regarding the exploitation of these enzymes for sustainable oxidation of phenolic compounds in wastewater, and suggests a way forward.

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