Comparison of Swept-Frequency Transfer Function and Pulse Testing of a Full Scale Graphite Wingbox Test Article to Support Lightning Indirect Effects Analysis

2001 ◽  
Author(s):  
Mike Dosch ◽  
Joe Heeter ◽  
Barbara Melander
Keyword(s):  
Transfer Function ◽  
Indirect Effects ◽  
Full Scale ◽  
Test Article ◽  
Pulse Testing ◽  
Frequency Transfer

Experimental Development of On-Line Flame Transfer Function Measurements for Fielded Gas Turbines

2021 ◽  
Author(s):  
Austin Matthews ◽  
Anna Cobb ◽  
Subodh Adhikari ◽  
David Wu ◽  
Tim Lieuwen ◽  
...  
Keyword(s):  
Transfer Function ◽  
Heat Release ◽  
Gas Turbine ◽  
Gas Turbines ◽  
High Speed ◽  
Transfer Functions ◽  
Full Scale ◽  
Fuel Injector ◽  
Experimental Development ◽  
On Line

Abstract Understanding thermoacoustic instabilities is essential for the reliable operation of gas turbine engines. To complicate this understanding, the extreme sensitivity of gas turbine combustors can lead to instability characteristics that differ across a fleet. The capability to monitor flame transfer functions in fielded engines would provide valuable data to improve this understanding and aid in gas turbine operability from R&D to field tuning. This paper presents a new experimental facility used to analyze performance of full-scale gas turbine fuel injector hardware at elevated pressure and temperature. It features a liquid cooled, fiber-coupled probe that provides direct optical access to the heat release zone for high-speed chemiluminescence measurements. The probe was designed with fielded applications in mind. In addition, the combustion chamber includes an acoustic sensor array and a large objective window for verification of the probe using high-speed chemiluminescence imaging. This work experimentally demonstrates the new setup under scaled engine conditions, with a focus on operational zones that yield interesting acoustic tones. Results include a demonstration of the probe, preliminary analysis of acoustic and high speed chemiluminescence data, and high speed chemiluminescence imaging. The novelty of this paper is the deployment of a new test platform that incorporates full-scale engine hardware and provides the ability to directly compare acoustic and heat release response in a high-temperature, high-pressure environment to determine the flame transfer functions. This work is a stepping-stone towards the development of an on-line flame transfer function measurement technique for production engines in the field.

scholarly journals A Review of Similitude Methods for Structural Engineering

2019 ◽  
Vol 71 (3) ◽  
Author(s):  
Alessandro Casaburo ◽  
Giuseppe Petrone ◽  
Francesco Franco ◽  
Sergio De Rosa
Keyword(s):  
Size Effects ◽  
Structural Engineering ◽  
Necessary Conditions ◽  
Rate Sensitivity ◽  
Full Scale ◽  
Test Article ◽  
Depth Analysis ◽  
Prototype Structure ◽  
Similitude Theory ◽  
Full Scale Testing

Similitude theory allows engineers, through a set of tools known as similitude methods, to establish the necessary conditions to design a scaled (up or down) model of a full-scale prototype structure. In recent years, to overcome the obstacles associated with full-scale testing, such as cost and setup, research on similitude methods has grown and their application has expanded into many branches of engineering. The aim of this paper is to provide as comprehensive a review as possible about similitude methods applied to structural engineering and their limitations due to size effects, rate sensitivity phenomena, etc. After a brief historical introduction and a more in-depth analysis of the main methods, the paper focuses on similitude applications classified, first, by test article, then by engineering fields.

Phase measurement of nonuniform phase-shifted interferograms using the frequency transfer function

2019 ◽  
Vol 58 (15) ◽  
pp. 4157 ◽  
Author(s):  
Ivan Choque ◽  
Manuel Servin ◽  
Moises Padilla ◽  
Miguel Asmad ◽  
Sotero Ordones
Keyword(s):  
Transfer Function ◽  
Phase Measurement ◽  
Frequency Transfer

Frequency Transfer Function From Fluid Temperature Fluctuations to Stress Intensity Factors

2003 ◽  
Author(s):  
Naoto Kasahara ◽  
Masanori Ando ◽  
Ihciro Furuhashi ◽  
Chen Fuquan ◽  
Hideki Takasho
Keyword(s):  
Stress Intensity ◽  
Transfer Function ◽  
Stress Intensity Factors ◽  
Temperature Fluctuation ◽  
Fatigue Cracks ◽  
Temperature Fluctuations ◽  
Fluid Temperature ◽  
Intensity Factors ◽  
Rational Analysis ◽  
Frequency Transfer

Temperature fluctuation from incomplete fluid mixing can induce fatigue cracks on structures of nuclear components, which should be prevented. For rational analysis of this phenomenon, the authors have developed a frequency transfer function that translates fluid temperature fluctuation to stress intensity factors. This function is formulated by a product of the effective heat transfer and the stress intensity factor functions, and enables us to quickly calculate stresses intensity factors induced by fluid temperature fluctuations. Furthermore, it can evaluate sensitivities of stress intensity factors to frequencies of temperature fluctuation, Biot number and constraint conditions of structures. Applicability of this function was verified through comparison with stress intensity factors calculated by the finite element method.

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