The Use of Perforated Damping Liners in Aero Gas Turbine Combustion Systems

2011 ◽  
Author(s):  
Jochen Rupp ◽  
Jon Carrotte ◽  
Michael Macquisten
Keyword(s):  
Pressure Drop ◽  
Flow Field ◽  
Gas Turbine ◽  
Analytical Model ◽  
Operating Conditions ◽  
Acoustic Energy ◽  
Fuel Injector ◽  
Flame Tube ◽  
Gas Turbine Combustion ◽  
Combustion Systems

This paper considers the use of perforated porous liners for the absorption of acoustic energy within aero style gas turbine combustion systems. The overall combustion system pressure drop means that the porous liner (or ‘damping skin’) is typically combined with a metering skin. This enables most of the mean pressure drop, across the flame tube, to occur across the metering skin with the porous liner being exposed to a much smaller pressure drop. In this way porous liners can potentially be designed to provide significant levels of acoustic damping, but other requirements (e.g. cooling, available space envelope etc) must also be considered as part of this design process. A passive damper assembly was incorporated within an experimental isothermal facility that simulated an aero-engine style flame tube geometry. The damper was therefore exposed to the complex flow field present within an engine environment (e.g. swirling efflux from a fuel injector, coolant film passing across the damper surface etc.). In addition, plane acoustic waves were generated using loudspeakers so that the flow field was subjected to unsteady pressure fluctuations. This enabled the performance of the damper, in terms of its ability to absorb acoustic energy, to be evaluated. To complement the experimental investigation a simplified 1D analytical model was also developed and validated against the experimental results. In this way not only was the performance of the acoustic damper evaluated, but also the fundamental processes responsible for this measured performance could be identified. Furthermore the validated analytical model also enabled a wide range of damping geometry to be assessed for a range of operating conditions. In this way damper geometry can be optimized (e.g. for a given space envelope) whilst the onset of non-linear absorption (and hence the potential to ingest hot gas) can also be identified.

The Use of Perforated Damping Liners in Aero Gas Turbine Combustion Systems

2012 ◽  
Vol 134 (7) ◽  
Author(s):  
Jochen Rupp ◽  
Jon Carrotte ◽  
Michael Macquisten
Keyword(s):  
Pressure Drop ◽  
Flow Field ◽  
Gas Turbine ◽  
Analytical Model ◽  
Operating Conditions ◽  
Acoustic Energy ◽  
Fuel Injector ◽  
Flame Tube ◽  
Gas Turbine Combustion ◽  
Combustion Systems

This paper considers the use of perforated porous liners for the absorption of acoustic energy within aero style gas turbine combustion systems. The overall combustion system pressure drop means that the porous liner (or “damping skin”) is typically combined with a metering skin. This enables most of the mean pressure drop, across the flame tube, to occur across the metering skin with the porous liner being exposed to a much smaller pressure drop. In this way porous liners can potentially be designed to provide significant levels of acoustic damping, but other requirements (e.g., cooling, available space envelope, etc) must also be considered as part of this design process. A passive damper assembly was incorporated within an experimental isothermal facility that simulated an aero-engine style flame tube geometry. The damper was therefore exposed to the complex flow field present within an engine environment (e.g., swirling efflux from a fuel injector, coolant film passing across the damper surface, etc.). In addition, plane acoustic waves were generated using loudspeakers so that the flow field was subjected to unsteady pressure fluctuations. This enabled the performance of the damper, in terms of its ability to absorb acoustic energy, to be evaluated. To complement the experimental investigation a simplified one-dimensional (1D) analytical model was also developed and validated against the experimental results. In this way not only was the performance of the acoustic damper evaluated, but also the fundamental processes responsible for this measured performance could be identified. Furthermore, the validated analytical model also enabled a wide range of damping geometry to be assessed for a range of operating conditions. In this way damper geometry can be optimized (e.g., for a given space envelope) while the onset of nonlinear absorption (and hence the potential to ingest hot gas) can also be identified.

scholarly journals Optical Characterization of a Multipoint Lean Direct Injector for Gas Turbine Combustors: Velocity and Fuel Drop Size Measurements

2010 ◽  
Author(s):  
Christopher M. Heath ◽  
Yolanda R. Hicks ◽  
Robert C. Anderson ◽  
Randy J. Locke
Keyword(s):  
Gas Turbine ◽  
Drop Size ◽  
Fuel Injection ◽  
Direct Injection ◽  
Operating Conditions ◽  
Diagnostic Methods ◽  
Spray Angle ◽  
Fuel Injector ◽  
Flame Tube ◽  
Component Velocity

Performance of a multipoint, lean direct injection (MP-LDI) strategy for low emission aero-propulsion systems has been tested in a Jet-A fueled, lean flame tube combustion rig. Operating conditions for the series of tests included inlet air temperatures between 672 K and 828 K, pressures between 1034 kPa and 1379 kPa and total equivalence ratios between 0.41 and 0.45, resulting in equilibrium flame temperatures approaching 1800 K. Ranges of operation were selected to represent the spectrum of subsonic and supersonic flight conditions projected for the next-generation of commercial aircraft. This document reports laser-based measurements of in situ fuel velocities and fuel drop sizes for the NASA 9-point LDI hardware arranged in a 3 × 3 square grid configuration. Data obtained represent a region of the flame tube combustor with optical access that extends 38.1-mm downstream of the fuel injection site. All data were obtained within reacting flows, without particle seeding. Two diagnostic methods were employed to evaluate the resulting flow path. Three-component velocity fields have been captured using phase Doppler interferometry (PDI), and two-component velocity distributions using planar particle image velocimetry (PIV). Data from these techniques have also offered insight into fuel drop size and distribution, fuel injector spray angle and pattern, turbulence intensity, degree of vaporization and extent of reaction. This research serves to characterize operation of the baseline NASA 9-point LDI strategy for potential use in future gas-turbine combustor applications. An additional motive is the compilation of a comprehensive database to facilitate understanding of combustor fuel injector aerodynamics and fuel vaporization processes, which in turn may be used to validate computational fluid dynamics codes, such as the National Combustor Code (NCC), among others.

Interaction Between the Acoustic Pressure Fluctuations and the Unsteady Flow Field Through Circular Holes

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
Jochen Rupp ◽  
Jon Carrotte ◽  
Adrian Spencer
Keyword(s):  
Velocity Field ◽  
Flow Field ◽  
Gas Turbine ◽  
Nonlinear Absorption ◽  
Acoustic Pressure ◽  
Pressure Fluctuations ◽  
Type Systems ◽  
Linear And Nonlinear ◽  
Gas Turbine Combustion ◽  
Combustion Systems

Gas turbine combustion systems are prone to thermo-acoustic instabilities, and this is particularly the case for new low emission lean burn type systems. The presence of such instabilities is basically a function of the unsteady heat release within the system (i.e., both magnitude and phase) and the amount of damping. This paper is concerned with this latter process and the potential damping provided by perforated liners and other circular apertures found within gas turbine combustion systems. In particular, the paper outlines experimental measurements that characterize the flow field within the near field region of circular apertures when being subjected to incident acoustic pressure fluctuations. In this way the fundamental process by which acoustic energy is converted into kinetic energy of the velocity field can be investigated. Experimental results are presented for a single orifice located in an isothermal duct at ambient test conditions. Attached to the duct are two loudspeakers that provide pressure fluctuations incident onto the orifice. Unsteady pressure measurements enable the acoustic power absorbed by the orifice to be determined. This was undertaken for a range of excitation amplitudes and mean flows through the orifice. In this way regimes where both linear and nonlinear absorption occur along with the transition between these regimes can be investigated. The key to designing efficient passive dampers is to understand the interaction between the unsteady velocity field, generated at the orifice and the acoustic pressure fluctuations. Hence experimental techniques are also presented that enable such detailed measurements of the flow field to be made using particle image velocimetry. These measurements were obtained for conditions at which linear and nonlinear absorption was observed. Furthermore, proper orthogonal decomposition was used as a novel analysis technique for investigating the unsteady coherent structures responsible for the absorption of energy from the acoustic field.

Assessment and Prediction of Helmholtz Resonator Performance Within Gas Turbine Combustion Systems

2014 ◽  
Author(s):  
Jochen Rupp ◽  
Graham Peacock ◽  
Gavita Regunath ◽  
Jon Carrotte
Keyword(s):  
Gas Turbine ◽  
Performance Comparison ◽  
Operating Conditions ◽  
Noise Levels ◽  
Neck Length ◽  
Linear Absorption ◽  
Fluid Displacement ◽  
Hot Gas ◽  
Gas Turbine Combustion ◽  
Combustion Systems

This paper is concerned with the potential use of Helmholtz resonators to provide increased acoustic damping within aero gas turbine combustion systems. Experimental measurements were undertaken using a high intensity facility into which a three burner combustor sector (non-reacting) model could be incorporated. In this way the performance of various damper geometry combinations were assessed. The effect of incident noise levels was also considered along with the associated transition from linear absorption (i.e. where absorption is directly proportional to incident pressure magnitude) to nonlinear absorption (i.e. where the proportion of acoustic loss decreases with increasing noise levels). This complicates the performance comparison between different damping geometries and means care is required when relating laboratory to engine operating conditions. In addition, all the measurements were undertaken in the presence of fuel injectors and other realistic flow field features found within a combustion system and which could affect damping performance. Finally, experimental and numerical assessment was made of the noise levels at which ingestion of hot gas will occur into the resonator cavities with and without the presence of a purging flow. For the geometries investigated ingestion occurs when the fluid displacement in the neck during an acoustic cycle is approximately equal to, or greater than, the resonator neck length. The ratio of fluid displacement and neck length provides a limit for the noise levels at which hot gas is ingested into the cavity and hence the operating condition where damping performance and system mechanical integrity is significantly compromised.

Flow Field in the Vicinity of a High-Pressure-Drop Ball Valve

2006 ◽  
Author(s):  
Lei-Yong Jiang ◽  
Keith Depooter ◽  
William Carscallen
Keyword(s):  
Pressure Drop ◽  
Flow Field ◽  
Gas Turbine ◽  
High Pressures ◽  
Elevated Temperatures ◽  
Numerical Study ◽  
Control Valve ◽  
Operating Conditions ◽  
Strong Interactions ◽  
Complex Flow

The testing of gas turbine combustors requires large flow rates at high pressures and elevated temperatures. In order to control the flow and pressure inside the combustor, some type of control valve is required in the exhaust section of the testing system. This backpressure valve is exposed to severe operating conditions. To understand the complex flow features in the exhaust section and provide relevant information for selecting suitable low-cost valves for new large test cells, a numerical study was carried out on a backpressure valve that has been used in a number of testing programs. The flow fields in the vicinity of the valve and the piping sections ending at the exhaust stack were resolved for three practical operating conditions. The results indicate that because of the presence of the valve with a V-shape opening, the flow field behind experiences a series of three-dimensional expansion and shock waves. The strong interactions exist between the flow behind the blockage and the flow passing through the opening area. More importantly, it is found that most of the pressure drop occurs immediately downstream of the valve, and its values are much larger than those provided by suppliers based on shock-free flow calculation. This may explain why the valve lost its function during testing and its stainless-steel seat had to be removed in order to maintain its rotational function. Based on this study, it is recommended that a second pressure-drop element be installed in the exhaust section in order to keep the expected lifetime of valves and reduce noise level. This suggestion has been implemented in the new large test cell at the Gas Turbine Laboratory.

Interaction Between the Acoustic Pressure Fluctuations and the Unsteady Flow Field Through Circular Holes

2009 ◽  
Author(s):  
Jochen Rupp ◽  
Jon Carrotte ◽  
Adrian Spencer
Keyword(s):  
Velocity Field ◽  
Flow Field ◽  
Gas Turbine ◽  
Acoustic Pressure ◽  
Pressure Fluctuations ◽  
Type Systems ◽  
Linear Absorption ◽  
Non Linear ◽  
Gas Turbine Combustion ◽  
Combustion Systems

Gas turbine combustion systems are prone to thermo-acoustic instabilities, and this is particularly the case for new, low emission, lean burn type systems. The presence of such instabilities is basically a function of the unsteady heat release within the system (i.e. both magnitude and phase), and the amount of damping. This paper is concerned with this latter process and the potential damping provided by perforated liners and other circular apertures found within gas turbine combustion systems. In particular the paper outlines experimental measurements that characterise the flow field within the near field region of circular apertures when being subjected to incident acoustic pressure fluctuations. In this way the fundamental process by which acoustic energy is converted into kinetic energy of the velocity field can be investigated. Experimental results are presented for a single orifice located in an isothermal duct at ambient test conditions. Attached to the duct are two loudspeakers that provide pressure fluctuations incident onto the orifice. Unsteady pressure measurements enable the acoustic power absorbed by the orifice to be determined. This was undertaken for a range of excitation amplitudes and mean flows through the orifice. In this way regimes where both linear and non-linear absorption occur along with the transition between these regimes can be investigated. The key to designing efficient passive dampers is to understand the interaction between the unsteady velocity field, generated at the orifice, and the acoustic pressure fluctuations. Hence experimental techniques are also presented that enable such detailed measurements of the flow field to be made using PIV. These measurements were obtained for conditions at which linear and non-linear absorption was observed. Furthermore, Proper Orthogonal Decomposition was used as a novel analysis technique for investigating the unsteady coherent structures responsible for the absorption of energy from the acoustic field.

scholarly journals A Developed Model for the Prediction of Soot Formation and Oxidation in the Gas Turbine

1985 ◽  
Author(s):  
Yousef S. H. Najjar
Keyword(s):  
Gas Turbine ◽  
Analytical Model ◽  
Soot Formation ◽  
Loading Conditions ◽  
Predictive Capability ◽  
Flame Tube ◽  
Pollution Problem ◽  
Gas Turbine Combustion ◽  
Full Loading ◽  
Good Agreement

Soot formation and oxidation are important in the field of gas turbine combustion in as much as they affect the flame tube durability and the pollution problem. Therefore, an analytical model was designed and it is here developed further to increase its predictive capability. Results show very good agreement between the model and the measurements at both idle and full loading conditions.

scholarly journals A Comparative Study on Fault Detection Methods for Gas Turbine Combustion Systems

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 389
Author(s):  
Jinfu Liu ◽  
Zhenhua Long ◽  
Mingliang Bai ◽  
Linhai Zhu ◽  
Daren Yu
Keyword(s):  
Fault Detection ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Operating Conditions ◽  
Detection Methods ◽  
Distribution Model ◽  
Outlet Temperature ◽  
Combustion System ◽  
Comparison Results ◽  
Gas Turbine Combustion

As one of the core components of gas turbines, the combustion system operates in a high-temperature and high-pressure adverse environment, which makes it extremely prone to faults and catastrophic accidents. Therefore, it is necessary to monitor the combustion system to detect in a timely way whether its performance has deteriorated, to improve the safety and economy of gas turbine operation. However, the combustor outlet temperature is so high that conventional sensors cannot work in such a harsh environment for a long time. In practical application, temperature thermocouples distributed at the turbine outlet are used to monitor the exhaust gas temperature (EGT) to indirectly monitor the performance of the combustion system, but, the EGT is not only affected by faults but also influenced by many interference factors, such as ambient conditions, operating conditions, rotation and mixing of uneven hot gas, performance degradation of compressor, etc., which will reduce the sensitivity and reliability of fault detection. For this reason, many scholars have devoted themselves to the research of combustion system fault detection and proposed many excellent methods. However, few studies have compared these methods. This paper will introduce the main methods of combustion system fault detection and select current mainstream methods for analysis. And a circumferential temperature distribution model of gas turbine is established to simulate the EGT profile when a fault is coupled with interference factors, then use the simulation data to compare the detection results of selected methods. Besides, the comparison results are verified by the actual operation data of a gas turbine. Finally, through comparative research and mechanism analysis, the study points out a more suitable method for gas turbine combustion system fault detection and proposes possible development directions.

Sign in / Sign up

Export Citation Format

Share Document