A Study on the Effects of Geometric Non Linearities on the Un-Running Transformation of Compressor Blades

2014 ◽  
Author(s):  
Vicente P. Timon ◽  
Roque Corral
Keyword(s):  
Elastic Modulus ◽  
Rotational Speed ◽  
Compressor Blade ◽  
Large Displacement ◽  
Mass Model ◽  
Compressor Blades ◽  
Linear Solver ◽  
The Given ◽  
Selection Of ◽  
Blade Geometry

A manufactured, cold, turbomachinery blade will deform elastically under the design centrifugal, aerodynamic and thermal loads, giving the hot blade geometry. The hot-to-cold transformation or blade unrunning process consist in the calculation of the cold blade geometry which, when subject to the design conditions, will deform to match the given hot blade geometry. This paper will use a simple spring-mass model to show how the selection of geometrically linear or large displacement, geometrically non-linear, structural solvers affect the hot-to-cold transformation for compressor blades. The geometrically linear solver gives good results below a certain value of the rotational speed, which depends on the blade geometry and on the ratio of density to elastic modulus of the blade material. Above that speed, the geometrically linear solver predicts unrealistically high deformations. This model is applied to a realistic compressor blade, showing the same behavior.

scholarly journals Simultaneous Robust Design and Tolerancing of Compressor Blades

2014 ◽  
Author(s):  
Eric A. Dow ◽  
Qiqi Wang
Keyword(s):  
Robust Design ◽  
Gaussian Random Field ◽  
Compressor Blade ◽  
Optimization Techniques ◽  
Manufacturing Cost ◽  
Compressor Blades ◽  
Manufacturing Tolerances ◽  
The Mean ◽  
The Impact ◽  
Blade Geometry

The manufacturing processes used to create compressor blades inevitably introduce geometric variability to the blade surface. In addition to increasing the performance variability, it has been observed that introducing geometric variability tends to reduce the mean performance of compressor blades. For example, the mean adiabatic efficiency observed in compressor blades with geometric variability is typically lower than the efficiency in the absence of variability. This “mean-shift” in performance leads to increased operating costs over the life of the compressor blade. These detrimental effects can be reduced by using robust optimization techniques to optimize the blade geometry. The impact of geometric variability can also be reduced by imposing stricter tolerances, thereby directly reducing the allowable level of variability. However, imposing stricter manufacturing tolerances increases the cost of manufacturing. Thus, the blade design and tolerances must be chosen with both performance and manufacturing cost in mind. This paper presents a computational framework for performing simultaneous robust design and tolerancing of compressor blades subject to manufacturing variability. The manufacturing variability is modelled as a Gaussian random field with non-stationary variance to simulate the effects of spatially varying manufacturing tolerances. The statistical performance of the compressor blade system is evaluated using the Monte Carlo method. A gradient based optimization scheme is used to determine the optimal blade geometry and distribution of manufacturing tolerances.

Application of the turbidity ratio method in the spherical particle size determination in the range m ∈ and α ∈

1979 ◽  
Vol 44 (7) ◽  
pp. 2064-2078 ◽  
Author(s):  
Blahoslav Sedláček ◽  
Břetislav Verner ◽  
Miroslav Bárta ◽  
Karel Zimmermann
Keyword(s):  
Refractive Index ◽  
Spherical Particle ◽  
Ratio Method ◽  
Refractive Indices ◽  
Relative Refractive Index ◽  
Particle Size Determination ◽  
The Individual ◽  
The Given ◽  
Turbidity Ratio ◽  
Selection Of

Basic scattering functions were used in a novel calculation of the turbidity ratios for particles having the relative refractive index m = 1.001, 1.005 (0.005) 1.315 and the size α = 0.05 (0.05) 6.00 (0.10) 15.00 (0.50) 70.00 (1.00) 100, where α = πL/λ, L is the diameter of the spherical particle, λ = Λ/μ1 is the wavelength of light in a medium with the refractive index μ1 and Λ is the wavelength of light in vacuo. The data are tabulated for the wavelength λ = 546.1/μw = 409.357 nm, where μw is the refractive index of water. A procedure has been suggested how to extend the applicability of Tables to various refractive indices of the medium and to various turbidity ratios τa/τb obtained with the individual pairs of wavelengths λa and λb. The selection of these pairs is bound to the sequence condition λa = λ0χa and λb = λ0χb, in which b-a = δ = 1, 2, 3; a = -2, -1, 0, 1, 2, ..., b = a + δ = -1, 0, 1, 2, ...; λ0 = λa=0 = 326.675 nm; χ = 546.1 : 435.8 = 1.2531 is the quotient of the given sequence.

Designing Forging and Die Tooling for the Manufacture of Turbine Engine Compressor Blades in Siemens NX

2016 ◽  
Vol 684 ◽  
pp. 497-506 ◽  
Author(s):  
D.S. Goryainov ◽  
V.V. Anokhin ◽  
Aleksey Shlyapugin
Keyword(s):  
Point Cloud ◽  
Compressor Blade ◽  
Compressor Blades ◽  
Turbine Engine ◽  
Direct Modeling ◽  
Engine Compressor ◽  
Data Source ◽  
Theoretical Contour ◽  
Gas Turbine Compressor ◽  
Complex Parts

For designing forging and die tooling for bulk forging a necessity in using the data of the geometry of the part produced arises. Obviously, the use as a data source for designing drawings of commonly applied in “manual alternate design” (without a computer) especially such complex parts as compressor blades is not perspective because of the complexity of developing theoretical contour specified by a point cloud. In this case the use of special tooling of direct modeling that provides changing the original model of the part developed by the designers is a perspective one. It should be taken into account during the process of forging and die tooling designing that it is necessary to register the special features of the technology, upon that, the technologist should be highly proficient in using the software. The work given describes the designing technique of gas turbine compressor blade with the account of using the potential of NX Siemens program.

A Comparison of Inverse Models for the Estimation of Ice-Induced Propeller Moments on a Polar Vessel

2021 ◽  
Author(s):  
Brendon M. Nickerson ◽  
Anriëtte Bekker
Keyword(s):  
Rotational Speed ◽  
Continuous Model ◽  
Full Scale ◽  
Lumped Mass ◽  
Mass Model ◽  
Inverse Models ◽  
Lumped Mass Model ◽  
Ill Posed ◽  
Shaft Torque ◽  
Measurement Location

Abstract Full-scale measurements were conducted on the port side propulsion shaft the S.A. Agulhas II during the 2019 SCALE Spring Cruise. The measurements included the shaft torque captured at two separate measurement locations, and the shaft rotational speed at one measurement location. The ice-induced propeller moments are estimated from the full-scale shaft responses using two inverse models. The first is a published discrete lumped mass model that relies on regularization due to the inverse problem being ill-posed. This model is only able to make use of the propulsion shaft torque as inputs. The second model is new and employs modal superposition to represent the propulsion shaft as a combination of continuous modes, resulting in a well-posed problem. This new model requires the additional measurement of the shaft rotational speed for the inverse solution. The continuous model is shown to be more consistent and efficient, which allows its use in real-time monitoring of propeller moments.

Aeroelastic Properties of Closely Spaced Modes for a Highly Loaded Transonic Fan

2008 ◽  
Author(s):  
Hans Ma˚rtensson ◽  
Ste´fan Sturla Gunnsteinsson ◽  
Damian M. Vogt
Keyword(s):  
Rotational Speed ◽  
Pressure Ratio ◽  
Stability Margin ◽  
Frequency Separation ◽  
Mode Shapes ◽  
Compressor Blades ◽  
Aeroelastic System ◽  
High Pressure Ratio ◽  
Mode Separation ◽  
Centrifugal Stiffening

In the design of modern compressor blades of wide chord (low aspect ratio) type it is often hard to avoid having modes that are close to each other in frequency. Modes which are closely spaced can interact dynamically. Mistuning and localization of stresses are known problems with this. A potential problem with this is also the possibility of coalescence flutter of the modes. Even if the modes are frequency separated at zero rotational speed, the centrifugal stiffening may cause the modes to attract and even cross (or veer) at some rotational speed. In design, mode separation criteria are sometimes applied in order to minimize the risk of encountering unknown dynamic phenomena. This study is performed to better understand the dynamics of closely spaced modes with respect to risk for coalescence flutter. A reduced order aeroelastic system is then constructed that describes the interaction between the different modes. The aeroelastic couplings are then calculated for the 2 mode system. The method is general in terms of mode shapes and number of interacting modes. A parametrical study is performed in order to study how strongly the modes interact when the frequency separation is decreased and if there is a risk of destructive coalescence flutter. The investigation is performed on a high pressure ratio front stage fan blade. The tendency of the modes to interact depends on the strength of the coupling compared to the strength of the pure structural modes. The tendency towards instability was increased in cases where the stability margin was smaller of the single modes. The results can be considered to support a separation criterion of 2% for the lower. A re-evaluation should be considered if lighter blade material and increased loads are to be used.

scholarly journals THE STYLISTIC FUNCTIONING OF SCRIPTURAL ALLUSIONS IN AN EARLY MODERN ENGLISH PLAY “JOHAN BAPTYSTES PREACHYNGE” BY J. BALE

2020 ◽  
Vol 30 (6) ◽  
pp. 1001-1007
Author(s):  
A.A. Khavronich
Keyword(s):  
Early Modern ◽  
Early Modern English ◽  
Semantic Expansion ◽  
Early English ◽  
The Given ◽  
Selection Of

The given article analyzes the peculiarities of the stylistic functioning of allusions to the Holy Scripture within one religious play belonging to the modern early English period, namely “Johan Baptystes Preachynge” produced by a dramatist J. Bale. The analysis is performed from the standpoint of linguopoetics. We consider stylistic features via the correlation of form and meaning, dissection of the conceptual component, juxtaposition with medieval plays representing adaptations of the same scriptural plot. Within the framework of this analysis we identify and assess elements performing the function of impact incorporated into the scriptural allusions and estimate their role in the selection of other lexical units, construction of extended metaphors, syntactic shaping of particular fragments of the play. We draw a conclusion that via the extension of scriptural metaphorical complexes the author brings about a meaningful focus shift to ensure a protestant reinterpretation of the included biblical theses. A substantial share of stylistically marked elements undergoes semantic expansion and develops adherent connotations since they relate to the pivotal elements of the allusions.

scholarly journals Selection of the variant solution of forest road alignment conceptual design using multicriteria optimisation

2009 ◽  
pp. 165-176 ◽  
Author(s):  
Bogdan Stefanovic ◽  
Ivan Bjelanovic
Keyword(s):  
Conceptual Design ◽  
Multicriteria Optimization ◽  
Linear Distribution ◽  
Forest Road ◽  
Multicriteria Optimisation ◽  
Technical Production ◽  
The Given ◽  
Selection Of ◽  
Design Construction ◽  
Building Parameters

One of the three studied variant solutions of forest road conceptual design was selected based on the linear distribution of criteria, as the method of multicriteria optimization. The selection was performed with 25 parameters classified as economic, technical, production and social criteria. The parameters of technical criteria were grouped into design, construction and building parameters. Based on calculated nominal values of parameters by the given criteria, their ranking, comparison, point rating and scoring, the selected most favorable solution was variant 1.

scholarly journals Vulnerability analysis and method of selection of communication protocols for information transfer in Internet of Things systems

2021 ◽  
pp. 133-149
Author(s):  
Maryna Kolisnyk
Keyword(s):  
Internet Of Things ◽  
Initial Data ◽  
Information Transfer ◽  
System Analysis ◽  
Communication Protocols ◽  
Critical Systems ◽  
Smart Objects ◽  
Corporate System ◽  
The Given ◽  
Selection Of

The subject of study in the paper is the analysis of technologies, architectures, vulnerabilities and cyberattacks, communication patterns of smart objects, messaging models, and Internet of Things (IoT) / Web of Things (WoT) protocols for solving applied problems of critical and non-critical systems. The goal is to develop a method for selecting messaging models and application-level protocols in non-critical and critical multi-level IoT/WoT systems, provided that the type of access to intelligent objects is initially determined by the initial data, as well as analysis of vulnerabilities and attacks using these protocols. Objectives: to formalize the procedure for choosing communication protocols for IoT/WoT systems; analyze possible vulnerabilities of communication protocols; develop a method for selecting communication protocols for given initial data, depending on the selected type of communication template for smart objects; check practically the proposed method. The methods of research are methods of system analysis. The following results were obtained. The analysis of the features of communication protocols is conducted by comparing the main interrelated characteristics of IoT/WoT, the results of which are presented in the form of a table. A method has been developed for selecting communication protocols, depending on the selected type of communication template. The analysis of possible vulnerabilities of communication protocols and possible attacks using these protocols is conducted. The author has tested the method using the example of a corporate system (Smart House) based on the WoT concept. Findings. The scientific novelty of the results obtained is as follows: the analysis conducted in the paper shows that currently there is no unified approach to the choice of a messaging model and application-level protocols for building IoT/WoT, depending on the selected type of communication template for smart objects. The method for selecting communication protocols for the given conditions (for each IoT system its interaction pattern will correspond, depending on which components interact with each other), improved by the authors of the paper, makes it possible to simplify the task of using separate protocols for given IoT systems, considering vulnerabilities of protocols.

scholarly journals The Evaluation of Agricultural Land Use Sustainability in the Post-Socialist Camp Countries: Methodological and Practical Aspects

2021 ◽  
Vol 13 (2) ◽  
pp. 59-78
Author(s):  
Olena Kotykova ◽  
Mykola Babych
Keyword(s):  
Land Use ◽  
Agricultural Land ◽  
Sustainable Use ◽  
Correct Selection ◽  
Agricultural Land Use ◽  
Current State ◽  
Definition Of ◽  
The Given ◽  
Selection Of ◽  
Integral Indicator

An effective implementation of the sustainable use of agricultural land program is impossible without reliable results of the current state of the problem. In this sense, the correct selection of indicators and methods for determining the level of stability is important. The authors proposes the definition of the agricultural land use sustainability integral indicator based on three methodological approaches: the construction of the indicators system, each of them reflects some aspects of the land use sustainability at the macro level (according to the specific issues); the construction of the integral indicator for comparing the countries’ land use sustainability. According to the given methods it has been proved that agricultural land use in the countries of the post-socialist camp has a positive dynamics, but the sustainability indicators for all indicators have not achieved yet. This study was supported in part by the Erasmus SUPPA program – Jean Monnet Associations Application No 611556-EPP-1-2019-1-UA-EPPJMO-SUPPA.

scholarly journals A Generalization of the Blackwell–Ryll-Nardzewski Measurable Selection Theorem

2021 ◽  
Vol 134 (1) ◽  
pp. 35-41
Author(s):  
K.A. Afonin ◽  
◽  
Keyword(s):  
Metric Spaces ◽  
Transition Probability ◽  
Measurable Space ◽  
Measurable Selection ◽  
Selection Theorem ◽  
Borel Set ◽  
Borel Probability ◽  
Borel Mapping ◽  
The Given ◽  
Selection Of

One of the main forms of the measurable selection theorem is connected with the existence of the graph of a measurable mapping in a given measurable set 𝑆 in the product of two measurable spaces 𝑋 and 𝑌 . Such a graph enables one to pick a point in the section 𝑆𝑥 for each 𝑥 in 𝑋 such that the obtained mapping will be measurable. The indicated selection is called a measurable selection of the multi-valued mapping associating to the point 𝑥 the section 𝑆𝑥 , which is a set in 𝑌 . The classical theorem of Blackwell and Ryll-Nardzewski states that a Borel set 𝑆 in the product of two complete separable metric spaces contains the graph of a Borel mapping (hence admits a Borel selection) provided that there is a transition probability on this product with positive measures for all sections of 𝑆 . The main result of this paper gives a generalization to the case where only one of the two spaces is complete separable and the other one is a general measurable space whose points parameterize a family of Borel probability measures on the first space such that the sections of the given set 𝑆 in the product have positive measures.

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