High Momentum Jet Flames at Elevated Pressure: Part D — Simultaneous Measurements of OH/PAH PLIF and Mie Scattering on Liquid Fuels

2019 ◽  
Author(s):  
Dominik Schäfer ◽  
James D. Gounder ◽  
Oliver Lammel ◽  
Holger Ax ◽  
Rainer Lückerath ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Combustion Chamber ◽  
Gas Turbine ◽  
Mie Scattering ◽  
Liquid Fuels ◽  
High Momentum ◽  
Test Rig ◽  
Hot Gas ◽  
Liquid Phases

Abstract A promising alternative to modern swirl combustors for gas turbines are high momentum jet stabilized combustors. This gas turbine burner concept consists of circular arranged jet nozzles through which partially premixed high momentum jets enter the combustion chamber in axial direction. Furthermore, it features fuel flexibility, load flexibility and low pollutant emissions. The investigated generic combustor consists of an eccentric single nozzle in a square chamber. This nozzle represents a full-scale segment of a concentrically arranged multi-nozzle configuration. All measurements were carried out at the high pressure combustion test rig (HBK-S) at the German Aerospace Center (DLR) in Stuttgart. The generic single nozzle model combustor has been operated in a high-pressure test rig with large optical access in order to gain a detailed understanding of fuel distribution, droplet distribution, fuel air mixing and high temperature regions through various sections of the combustion chamber. For this purpose, different laser based measurement techniques have been applied simultaneously under gas turbine relevant conditions on liquid fuels (oil and oil/water). Other measurements in this combustor on gaseous fuels were presented in preceding (parts A and B) and current publications (part C). Mie scattering was used to visualize the liquid phase of oil and water downstream of the nozzle. In order to gain knowledge about the droplet velocity, a Nd:YAG double pulse laser at 532 nm was used for Particle Image Velocimetry (PIV). Additionally the gaseous and liquid phases of oil have been visualized through Planar Laser Induced Fluorescence (PLIF) by excitation of poly-cyclic aromatic hydrocarbons (PAHs) with a laser wavelength of 266 nm. To observe high temperature regions, OH and PAH PLIF was also performed with a low bandwidth at 283 nm from a Nd:YAG pumped dye laser. It was possible to separate the low-intensity OH signal of the hot gas regions from the PAH signal by collecting the different LIF signals simultaneously through a dual camera setup. Instantaneous PAH LIF images of the liquid and gaseous phase were compared with Mie scattering images for a qualitative impression of the evaporation. For this a structural comparison between the liquid phases of both images has been carried out. Results indicate, that the evaporation of most of the liquid fuel takes place near the hot gas region, as a large proportion of droplets are carried far downstream of the nozzle by the high momentum jet.

High Momentum Jet Flames at Elevated Pressure: A — Experimental and Numerical Investigation for Different Fuels

2017 ◽  
Author(s):  
Oliver Lammel ◽  
Michael Severin ◽  
Holger Ax ◽  
Rainer Lückerath ◽  
Andrea Tomasello ◽  
...  
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Elevated Pressure ◽  
Operating Conditions ◽  
Diagnostic Methods ◽  
Liquid Fuels ◽  
Main Stage ◽  
High Momentum ◽  
Gas Turbine Combustor ◽  
Jet Flames

In this work, results of comprehensive high-pressure tests and numerical simulations of high momentum jet flames in an optically accessible combustion chamber are presented. A generic single nozzle burner was designed as a full-scale representation of one duct of a high temperature FLOX® gas turbine combustor with a model pilot burner supporting the main nozzle. As an advanced step of the FLOX® gas turbine combustor development process, tests and simulations of the entire burner system (consisting of a multi nozzle main stage plus a pilot stage) are complemented with this work on an unscaled single nozzle combustor, thus supporting the development and testing of sub concepts and components like the mixing section and dual-fuel injectors. These injectors incorporate a gaseous fuel stage and a spray atomizer for liquid fuels, both separately exchangeable for testing of different fuel placement concepts. The combustor was successfully operated at gas turbine relevant conditions with natural gas including a variation of the Wobbe index, and with light heating oil with and without water admixture. The presented work is the first of two contributions and covers the description of the experimental setup, an overview of the numerical methods, high-pressure test results for different fuels and variations of the operating conditions including exhaust gas measurements and basic optical diagnostic methods, together with CFD results for several cases. The other part will present detailed and focused investigations of few conditions by complex and extensive optical and laser combustion diagnostics.

Comparison of 3D Unsteady Transient Conjugate Heat Transfer Analysis on a High Pressure Cooled Turbine Stage With Experimental Data

2017 ◽  
Author(s):  
Jong-Shang Liu ◽  
Mark C. Morris ◽  
Malak F. Malak ◽  
Randall M. Mathison ◽  
Michael G. Dunn
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Heat Flux ◽  
High Pressure ◽  
High Temperature ◽  
Gas Turbine ◽  
Conjugate Heat Transfer ◽  
Turbine Rotor ◽  
Turbine Stage ◽  
Cooling Flow

In order to have higher power to weight ratio and higher efficiency gas turbine engines, turbine inlet temperatures continue to rise. State-of-the-art turbine inlet temperatures now exceed the turbine rotor material capability. Accordingly, one of the best methods to protect turbine airfoil surfaces is to use film cooling on the airfoil external surfaces. In general, sizable amounts of expensive cooling flow delivered from the core compressor are used to cool the high temperature surfaces. That sizable cooling flow, on the order of 20% of the compressor core flow, adversely impacts the overall engine performance and hence the engine power density. With better understanding of the cooling flow and accurate prediction of the heat transfer distribution on airfoil surfaces, heat transfer designers can have a more efficient design to reduce the cooling flow needed for high temperature components and improve turbine efficiency. This in turn lowers the overall specific fuel consumption (SFC) for the engine. Accurate prediction of rotor metal temperature is also critical for calculations of cyclic thermal stress, oxidation, and component life. The utilization of three-dimensional computational fluid dynamics (3D CFD) codes for turbomachinery aerodynamic design and analysis is now a routine practice in the gas turbine industry. The accurate heat-transfer and metal-temperature prediction capability of any CFD code, however, remains challenging. This difficulty is primarily due to the complex flow environment of the high-pressure turbine, which features high speed rotating flow, coupling of internal and external unsteady flows, and film-cooled, heat transfer enhancement schemes. In this study, conjugate heat transfer (CHT) simulations are performed on a high-pressure cooled turbine stage, and the heat flux results at mid span are compared to experimental data obtained at The Ohio State University Gas Turbine Laboratory (OSUGTL). Due to the large difference in time scales between fluid and solid, the fluid domain is simulated as steady state while the solid domain is simulated as transient in CHT simulation. This paper compares the unsteady and transient results of the heat flux on a high-pressure cooled turbine rotor with measurements obtained at OSUGTL.

Analysis of Traction Characteristics of Grease-Lubricated Sliding Bearing

2013 ◽  
Vol 655-657 ◽  
pp. 640-643
Author(s):  
Bo Yuan Yang ◽  
Xiaofan Yan ◽  
Bing Su
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Room Temperature ◽  
Extreme Pressure ◽  
Test Rig ◽  
Sliding Bearing ◽  
Traction Coefficient ◽  
Lubrication Effect ◽  
Lubricated Sliding

Adopting the test rig of traction characteristics of grease-lubricated sliding bearing, the practical condition of sliding bearing was simulated and the traction coefficient of DGG Grease under different temperature, velocity and load was tested. Besides, the traction characteristics of the grease were also elaborated. The results indicate that the traction coefficient increases when the temperature gradually rises from room temperature while it gradually decreases when the temperature exceeds 85°C. Under the condition of high temperature and high pressure, the extreme pressure additive has obvious effects, the traction coefficient reducing and maintaining constant, so a better lubrication effect is realized.

Effects of Thermal Exposure on Microstructure and Mechanical Properties of Ni Based Superalloy GTD111

2011 ◽  
Vol 275 ◽  
pp. 31-34 ◽  
Author(s):  
Han Sang Lee ◽  
Keun Bong Yoo ◽  
Doo Soo Kim ◽  
Jae Hoon Kim
Keyword(s):  
High Temperature ◽  
Gas Turbine ◽  
Operating Temperature ◽  
Rupture Strength ◽  
Mechanical Test ◽  
Thermal Exposure ◽  
Creep Rupture Strength ◽  
Material Degradation ◽  
Temperature Dependent ◽  
Hot Gas

The rotating components in the hot sections of land-based gas turbine are exposed to severe environment during several ten thousand hours at above 1100 oC operating temperature. The failure mechanism of the hot gas components would be accompanied by material degradation in the properties of high temperature and creep rupture strength. Many hot gas components in gas turbine are made of Ni-based superalloy because of their high temperature performance. In this work, we surveyed the time and temperature dependent degradation of Ni-based superalloy. We prepared the specimens from GTD111 that are exposed at 871 oC and 982 oC in 1,000 ~ 10,000 hours. We carried out the mechanical test and microstructural observation.

Innovative Minimally Intrusive Sensor Technology Development for Versatile Affordable Advanced Turbine Engine Combustors

2002 ◽  
Author(s):  
Neil Goldstein ◽  
Carlos A. Arana ◽  
Fritz Bien ◽  
Jamine Lee ◽  
John Gruninger ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Real Time ◽  
Gas Turbines ◽  
High Performance ◽  
Chemical Species ◽  
Sensor Technology ◽  
Spectral Signature ◽  
Temperature Pattern ◽  
Hot Gas

The feasibility of an innovative minimally intrusive sensor for monitoring the hot gas stream at the turbine inlet in high performance aircraft gas turbine engines was demonstrated. The sensor uses passive fiber-optical probes and a remote readout device to collect and analyze the spatially resolved spectral signature of the hot gas in the combustor/turbine flowpaths. Advanced information processing techniques are used to extract the average temperature, temperature pattern factor, and chemical composition on a sub-second time scale. Temperatures and flame composition were measured in a variety of combustion systems including a high pressure, high temperature combustion cell. Algorithms for real-time temperature measurements were developed and demonstrated. This approach should provide a real-time temperature profile, temperature pattern factor, and chemical species sensing capability for multi-point monitoring of high temperature and high pressure flow at the combustor exit with application as an engine development diagnostic tool, and ultimately, as a real-time active control component for high performance gas turbines.

Investigation of Flame Stabilization in a High-Pressure Multi-Jet Combustor by Laser Measurement Techniques

2014 ◽  
Author(s):  
Oliver Lammel ◽  
Tim Rödiger ◽  
Michael Stöhr ◽  
Holger Ax ◽  
Peter Kutne ◽  
...  
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
Combustion Chamber ◽  
Gas Turbine ◽  
Recirculation Zone ◽  
Flame Stabilization ◽  
Operating Conditions ◽  
Pollutant Emissions ◽  
Single Shot ◽  
Optical Access

In this contribution, comprehensive optical and laser based measurements in a generic multi-jet combustor at gas turbine relevant conditions are presented. The flame position and shape, flow field, temperatures and species concentrations of turbulent premixed natural gas and hydrogen flames were investigated in a high-pressure test rig with optical access. The needs of modern highly efficient gas turbine combustion systems, i.e., fuel flexibility, load flexibility with increased part load capability, and high turbine inlet temperatures, have to be addressed by novel or improved burner concepts. One promising design is the enhanced FLOX® burner, which can achieve low pollutant emissions in a very wide range of operating conditions. In principle, this kind of gas turbine combustor consists of several nozzles without swirl, which discharge axial high momentum jets through orifices arranged on a circle. The geometry provides a pronounced inner recirculation zone in the combustion chamber. Flame stabilization takes place in a shear layer around the jet flow, where fresh gas is mixed with hot exhaust gas. Flashback resistance is obtained through the absence of low velocity zones, which favors this concept for multi-fuel applications, e.g. fuels with medium to high hydrogen content. The understanding of flame stabilization mechanisms of jet flames for different fuels is the key to identify and control the main parameters in the design process of combustors based on an enhanced FLOX® burner concept. Both experimental analysis and numerical simulations can contribute and complement each other in this task. They need a detailed and relevant data base, with well-known boundary conditions. For this purpose, a high-pressure burner assembly was designed with a generic 3-nozzle combustor in a rectangular combustion chamber with optical access. The nozzles are linearly arranged in z direction to allow for jet-jet interaction of the middle jet. This line is off-centered in y direction to develop a distinct recirculation zone. This arrangement approximates a sector of a full FLOX® gas turbine burner. The experiments were conducted at a pressure of 8 bar with preheated and premixed natural gas/air and hydrogen/air flows and jet velocities of 120 m/s. For the visualization of the flame, OH* chemiluminescence imaging was performed. 1D laser Raman scattering was applied and evaluated on an average and single shot basis in order to simultaneously and quantitatively determine the major species concentrations, the mixture fraction and the temperature. Flow velocities were measured using particle image velocimetry at different section planes through the combustion chamber.

Acoustic Measurements of Perforated Liners in Hot and Pressurized Flow

2013 ◽  
Author(s):  
Claus Lahiri ◽  
Karsten Knobloch ◽  
Friedrich Bake ◽  
Lars Enghardt
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Numerical Models ◽  
Experimental Tests ◽  
Acoustic Measurements ◽  
Test Rig ◽  
Acoustic Data ◽  
Bias Flow ◽  
Acoustic Instabilities ◽  
Acoustic Losses

Thermo-acoustic instabilities in gas turbine combustors can prevent the implementation of modern combustion concepts, which are essential for higher efficiency and lower emissions. Perforated combustor liners, especially in combination with a bias flow through the liner, are able to suppress the instabilities by increasing the acoustic losses of the system. Some insight into the parameter dependencies of the acoustic absorption has been gained by means of atmospheric testing at ambient temperature. The next step towards realistic testing conditions is taking into account high temperature and high pressure, which increases the effort of the experimental tests and the complexity of their analysis significantly. Tests in a real combustor can serve as a quality check of a given liner design, but are not appropriate for parameter studies. So far, numerical models accurate enough to enable the design of hot stream liners are simply not available, so that the experimental investigation of the liner’s dependency on temperature and pressure is essential for the transfer of laboratory scale results to a real engine application. A new test rig has been designed to overcome these problems. The Hot Acoustic Test rig (HAT) enables the study of the influence of pressure and temperature on the damping performance in an acoustically well defined environment, although the high temperature and high pressure conditions are challenging in terms of accurate acoustic measurements. This paper introduces the Hot Acoustic Test rig with its features and limitations and shows first examples of test results. The focus lies on the hardware, instrumentation, and analysis techniques that are necessary to obtain high quality acoustic data in hot and pressurized flow environments.

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