scholarly journals Stability Analysis of Multiharmonic Nonlinear Vibrations for Large Models of Gas Turbine Engine Structures With Friction and Gaps

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
E. P. Petrov
Keyword(s):  
Gas Turbine ◽  
Large Scale ◽  
Frequency Domain Analysis ◽  
Gas Turbine Engine ◽  
Forced Response ◽  
Scale Model ◽  
Turbine Engine ◽  
Nonlinear Springs ◽  
Large Scale Model ◽  
The Stability

An efficient method is proposed for the multiharmonic frequency-domain analysis of the stability for nonlinear periodic forced vibrations in gas turbine engine structures and turbomachines with friction, gaps, and other types of nonlinear contact interfaces. The method allows using large-scale finite element models for structural components together with detailed description of nonlinear interactions at contact interfaces between these components. The highly accurate reduced models are applied in the assessment of stability of periodic regimes for large-scale model of gas turbine structures. An approach is proposed for the highly accurate calculation of motion of a structure after it is perturbed from the periodic nonlinear forced response. Efficiency of the developed approach is demonstrated on a set of test cases including simple models and large-scale realistic bladed disk models with different types of nonlinearities: friction, gaps, and cubic nonlinear springs.

scholarly journals Stability Analysis of Multiharmonic Nonlinear Vibrations for Large Models of Gas-Turbine Engine Structures With Friction and Gaps

2016 ◽  
Author(s):  
E. P. Petrov
Keyword(s):  
Gas Turbine ◽  
Large Scale ◽  
Frequency Domain Analysis ◽  
Gas Turbine Engine ◽  
Forced Response ◽  
Scale Model ◽  
Turbine Engine ◽  
Nonlinear Springs ◽  
Large Scale Model ◽  
The Stability

An efficient method is proposed for the multiharmonic frequency domain analysis of the stability for nonlinear periodic forced vibrations in gas-turbine engine structures and turbomachines with friction, gaps and other types of nonlinear contact interfaces. The method allows using large-scale finite element models for structural components together with detailed description of nonlinear interactions at contact interfaces between these components. The highly accurate reduced models are applied in the assessment of stability of periodic regimes for large-scale model of gas-turbine structures. An approach is proposed for the highly-accurate calculation of motion of a structure after it is perturbed from the periodic nonlinear forced response. Efficiency of the developed approach is demonstrated on a set of test cases including simple models and large-scale realistic bladed disc models with different types of nonlinearities: friction, gaps and cubic nonlinear springs.

Review of the von Karman Institute Compression Tube Facility for Turbine Research

2013 ◽  
Author(s):  
G. Paniagua ◽  
C. H. Sieverding ◽  
T. Arts
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Measurement Techniques ◽  
Gas Turbine Engine ◽  
Modern Technology ◽  
Forced Response ◽  
Engine Operation ◽  
Turbine Engine ◽  
Von Karman ◽  
Von Kármán

Advances in turbine-based engine efficiency and reliability are achieved through better knowledge of the mechanical interaction with the flow. The life-limiting component of a modern gas turbine engine is the high-pressure (HP) turbine stage due to the arduous environment. For the same reason, real gas turbine engine operation prevents fundamental research. Various types of experimental approaches have been developed to study the flow and in particular the heat transfer, cooling, materials, aero-elastic issues and forced response in turbines. Over the last 30 years short duration facilities have dominated the research in the study of turbine heat transfer and cooling. Two decades after the development of the von Karman Institute compression tube facility (built in the 90s), one could reconsider the design choices in view of the modern technology in compression, heating, control and electronics. The present paper provides first the history of the development and then how the wind tunnel is operated. Additionally the paper disseminates the experience and best practices in specifically designed measurement techniques to both experimentalists and experts in data processing. The final section overviews the turbine research capabilities, providing details on the required upgrades to the test section.

Optimization of a Regenerative Gas Turbine Engine With Isothermal Heat Addition With the Genetic Algorithm

2009 ◽  
Author(s):  
E. Haghighi ◽  
B. Borzou ◽  
Amir R. Ghahremani ◽  
M. Behshad Shafii
Keyword(s):  
Genetic Algorithm ◽  
Gas Turbine ◽  
Large Scale ◽  
Thermodynamic Characteristics ◽  
Gas Turbine Engine ◽  
Engineering Problem ◽  
Turbine Engine ◽  
Heat Addition ◽  
Advanced Cycles ◽  
Gas Turbine Cycle

The use of advanced cycles to take advantage of the gas turbine’s thermodynamic characteristics has received increasing attention in recent years. These cycles have been developed for large scale power generation. Due to the powerful abilities of bio-inspired computing techniques such as Genetic Algorithm in locating the optimal (or near optimal) solutions to a given optimization problem, they are widely utilized for determining the parameters of different engineering systems in order to meet the specified performance objectives for a given problem. In order to illustrate the performance of one of these techniques, development and application of it for an engineering problem is presented. In this paper a regenerative gas turbine cycle, with isothermal heat addition has been analyzed. The optimization of system has been carried out numerically using the Genetic Algorithm method. Results show that the regenerative gas turbine engine, with isothermal heat addition, designed according to the optimum parameters condition gives the best performance and exhibits highest cycle efficiencies.

scholarly journals Analysis of Bifurcations in Multiharmonic Analysis of Nonlinear Forced Vibrations of Gas Turbine Engine Structures With Friction and Gaps

2016 ◽  
Vol 138 (10) ◽  
Author(s):  
E. P. Petrov
Keyword(s):  
Gas Turbine ◽  
Large Scale ◽  
Parameter Variation ◽  
Forced Vibrations ◽  
Forced Response ◽  
Operating Conditions ◽  
Frequency Domain Method ◽  
Cubic Nonlinearity ◽  
Turbine Engine ◽  
Detection And Localization

An efficient frequency-domain method has been developed to analyze the forced response of large-scale nonlinear gas turbine structures with bifurcations. The method allows detection and localization of the design and operating conditions sets where bifurcations occur, calculation of tangents to the solution trajectory, and continuation of solutions under parameter variation for structures with bifurcations. The method is aimed at calculation of steady-state periodic solution, and multiharmonic representation of the variation of displacements in time is used. The possibility of bifurcations in realistic gas-turbine structures with friction contacts and with cubic nonlinearity has been shown.

scholarly journals A Method for Parametric Analysis of Stability Boundaries for Nonlinear Periodic Vibrations of Structures With Contact Interfaces

2018 ◽  
Author(s):  
E. P. Petrov
Keyword(s):  
Parametric Analysis ◽  
Large Scale ◽  
Contact Stiffness ◽  
Stability Loss ◽  
Forced Response ◽  
Scale Model ◽  
Design Parameters ◽  
Stability Boundaries ◽  
Analysis Of Stability ◽  
The Stability

A method for parametric analysis of the stability loss boundary has been developed for periodic regimes of nonlinear forced vibrations for a first time. The method allows parametric frequency-domain calculations of the stability loss together with the vibration amplitudes and design parameter values corresponding to the stability boundaries. The tracing algorithm is applied to obtain the trajectories of stability loss points as functions of design parameters. The parametric stability loss is formulated for cases when: (i) the design parameters characterise the properties of nonlinear contact interfaces (e.g. gap, contact stiffness, friction coefficient, etc.) and (ii) the design parameters describe linear components of the analysed structure (e.g. parameters of geometric shape, material, natural frequencies, modal damping etc.) and (iii) these parameters describe the excitation loads (e.g. their level, distribution or frequency). An approach allowing the multiparametric analysis of stability boundaries is proposed. The method uses the multiharmonic representation of the periodic forced response and aimed at the analysis of realistic gas-turbine structures comprising thousands and millions degrees of freedom. The method can be used for the effective search of isolated branches of the nonlinear solutions and examples of detection and search of the isolated branches are given: for relatively small and for large-scale finite element models. The efficiency of the method for calculation of the stability boundaries and for the search of isolated branches is demonstrated on simple systems and on a large-scale model of a turbine blade.

scholarly journals A Method for Parametric Analysis of Stability Boundaries for Nonlinear Periodic Vibrations of Structures With Contact Interfaces

2018 ◽  
Vol 141 (3) ◽  
Author(s):  
E. P. Petrov
Keyword(s):  
Parametric Analysis ◽  
Large Scale ◽  
Contact Stiffness ◽  
Stability Loss ◽  
Forced Response ◽  
Scale Model ◽  
Design Parameters ◽  
Stability Boundaries ◽  
Analysis Of Stability ◽  
The Stability

A method for parametric analysis of the stability loss boundary has been developed for periodic regimes of nonlinear forced vibrations for a first time. The method allows parametric frequency-domain calculations of the stability loss together with the vibration amplitudes and design parameter values corresponding to the stability boundaries. The tracing algorithm is applied to obtain the trajectories of stability loss points as functions of design parameters. The parametric stability loss is formulated for cases when (i) the design parameters characterize the properties of nonlinear contact interfaces (e.g., gap, contact stiffness, and friction coefficient); (ii) the design parameters describe linear components of the analyzed structure (e.g., parameters of geometric shape, material, natural frequencies, and modal damping); and (iii) these parameters describe the excitation loads (e.g., their level, distribution or frequency). An approach allowing the multiparametric analysis of stability boundaries is proposed. The method uses the multiharmonic representation of the periodic forced response and aimed at the analysis of realistic gas-turbine structures comprising thousands and millions degrees-of-freedom (DOF). The method can be used for the effective search of isolated branches of the nonlinear solutions and examples of detection and search of the isolated branches are given: for relatively small and for large-scale finite element (FE) models. The efficiency of the method for calculation of the stability boundaries and for the search of isolated branches is demonstrated on simple systems and on a large-scale model of a turbine blade.

scholarly journals EXTERNAL AND INTERNAL WAVE SET-UP AT POROUS PBA REVETMENTS ON A SAND FOUNDATION

2012 ◽  
Vol 1 (33) ◽  
pp. 27
Author(s):  
Gisa Foyer ◽  
Hocine Oumeraci
Keyword(s):  
Large Scale ◽  
Wave Length ◽  
Irregular Waves ◽  
Scale Model ◽  
Large Scale Model ◽  
Internal Set ◽  
Deep Water Wave ◽  
Set Up ◽  
The Stability ◽  
Almost All

Wave set-up is generally considered for the stability analysis of beaches, but not or not explicitly for the design of revetments. Based on large-scale model results with regular and irregular waves, it is shown in this paper that this is not justified. For this purpose, the wave set-up on a porous bonded revetment and the related internal set-up in the sand foundation below the revetment are analysed for different breaker types. The results particularly show that (i) considerable set-up values are obtained for almost all breaker types, (ii) a good correlation exists with the deep water wave length for both external and internal set-up and (iii) the internal set-up is significantly affected by the wave set-up on the slope. Empirical formulae for the prediction of the external and internal set-up are also proposed for both regular and irregular waves.

Large-Scale Investigations of Geotextile Sandcontainers Used for Scour Protection of Offshore Monopiles Supporting Wind Energy Turbines

2006 ◽  
Author(s):  
Joachim Gru¨ne ◽  
Uwe Sparboom ◽  
Reinold Schmidt-Koppenhagen ◽  
Zeya Wang ◽  
Hocine Oumeraci
Keyword(s):  
Large Scale ◽  
Research Programme ◽  
Scale Model ◽  
Research Centre ◽  
Large Wave ◽  
Wave Channel ◽  
Large Scale Model ◽  
First Results ◽  
The Stability ◽  
Scour Protection

An innovative scour protection for monopile structures was proposed by using geotextile sand containers in a research programme started recently. Large-scale model tests on the stability of such alternative scour protection are being performed in the Large Wave Channel (GWK) of the Coastal Research Centre (FZK). First results are reported from basic test series performed with single geotextile sand containers and container groups with different container weights, varied in sizes and percentages of filling. Further an empirical approach on the stability of sand containers is estimated as a first approximation from the results.

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