scholarly journals Full-Scale Turbofan-Engine Turbine-Transfer Function Determination Using Three Internal Sensors

2011 ◽  
Author(s):  
Lennart Hultgren
Keyword(s):  
Transfer Function ◽  
Full Scale ◽  
Turbofan Engine

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 Turbine Noise: Its Significance in the Civil Aircraft Noise Problem

1969 ◽  
Author(s):  
M. J. T. Smith ◽  
K. W. Bushell
Keyword(s):  
Aircraft Noise ◽  
Full Scale ◽  
Engine Noise ◽  
Turbofan Engine ◽  
Significant Contributor ◽  
Civil Aircraft ◽  
Available Information

The authors show the presence of noise from the turbine of a turbojet or turbofan engine to be a significant contributor the overall engine noise. They review currently available information from both full-scale engines and model turbines and correlate it along lines following those previously developed for fans and compressors.

On the Effect of Short-Crestedness on Ship Motions

1966 ◽  
Vol 10 (03) ◽  
pp. 192-200
Author(s):  
E. O. Tuck
Keyword(s):  
Transfer Function ◽  
Transfer Functions ◽  
Full Scale ◽  
Slender Body ◽  
Ship Motions ◽  
Forward Speed ◽  
Slender Body Theory ◽  
Random Seas ◽  
Body Theory

A simple mathematical example, using the slender-body theory of ship motions, is given to illustrate the nature of errors due to short-crestedness in estimations of ship transfer functions from full-scale measurements in directionally random seas. As expected physically, any transfer function obtained in this manner is a smoothed estimate of the true transfer function which would be observed in a unidirectional sea. Computations of this "pseudotransfer function" are presented for heave and pitch of an idealized ship at zero speed, and the effects of forward speed are discussed briefly.

Thermoacoustic Analysis of Gas Turbine Combustion Systems Using Unsteady CFD

2005 ◽  
Author(s):  
Bruno Schuermans ◽  
Holger Luebcke ◽  
Denis Bajusz ◽  
Peter Flohr
Keyword(s):  
Transfer Function ◽  
Boundary Conditions ◽  
Gas Turbine ◽  
Network Model ◽  
Full Scale ◽  
Test Facility ◽  
Combustion System ◽  
Acoustic Boundary Conditions ◽  
Gas Turbine Combustion ◽  
Gas Turbine Burner

Unsteady Computational Fluid Dynamics (CFD) has been used to predict thermoacoustic interaction processes in an industrial gas turbine burner. Because detailed unsteady simulation of an entire gas turbine combustion system is forbiddingly expensive, two different approaches have been applied to overcome this problem. In the first approach, time-domain acoustic boundary conditions are applied to the computational domain of the CFD. The idea is to model in CFD only that part of the problem that cannot be represented by low order (acoustic) models. The advantage is not only that the method is much faster; it also allows changes in acoustic boundary conditions without a need to make a new mesh for the problem. This method introduced here is novel and can be used to apply any (causal) acoustic impedance matrix to a CFD computation. The desired impedance can either be obtained analytically, from an acoustic network model or from an acoustic finite element code. The method has been tested on various test cases and proved to be accurate and robust. First, a simple duct with non reactive flow has been simulated. A non refelecting boundary condition for plane waves has been applied. In a further step the methodology was implemented on a gas turbine burner with combustion. The measured acoustic boundary conditions of a single burner test facility have been applied. The predicted pressure spectra are in reasonable agreement with measured pulsation spectra of a full-scale gas turbine burner in an atmospheric combustion test facility. In the second approach a system identification technique is used in a post-processing step of the CFD results. In this way the transfer function relating the acoustic quantities on both sides of the flame is obtained. This transfer function can then be applied to an acoustic network model of the system. The advantage of this method is that once the transfer matrix of the combustion zone is obtained, the influence of combustion system geometry can be investigated in the low order model, which is very fast. This method has been compared with measured transfer matrices of a full-scale swirl stabilized gas turbine burner and proved to be in good agreement.

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