Performance Assessment of a Prototype Trapped Vortex Combustor Concept for Gas Turbine Application

2001 ◽  
Author(s):  
D. L. Burrus ◽  
A. W. Johnson ◽  
W. M. Roquemore ◽  
D. T. Shouse
Keyword(s):  
Gas Turbine ◽  
Combustion Efficiency ◽  
Operating Conditions ◽  
Gas Temperature ◽  
Test Rig ◽  
Turbine Engine ◽  
Run Time ◽  
K 12 ◽  
Trapped Vortex ◽  
Type Fuel

GE Aircraft Engines and the Air Force Research Laboratory have been jointly developing a novel combustor technology concept for potential application in gas turbine engines. This novel combustor concept is known as the Trapped Vortex Combustor (TVC). The GE and AFRL team began work on the design of a prototypical TVC test rig in 1996. This effort represents the extension of earlier AFRL research with the TVC [1,2]. This work led to the fabrication of a 30.5 cm wide rectangular sector test rig capable of operation at inlet pressures up to 20.5 atmospheres, inlet temperatures up to 900 K, and to stoichiometric discharge conditions. Testing of the rectangular sector rig was initiated in mid year 1998. The performance evaluation performed on the test rig covered all aspects of gas turbine combustor performance and operability including ground start ignition, lean blowout, altitude re-light, emissions, combustion efficiency, exit gas temperature profile, and structural metal temperatures. Test rig operating conditions provided simulations of current commercial and military aircraft gas turbine engine cycles as well as some advanced engine cycles, with JP-8 type fuel. Data was also obtained at selected operating conditions for the LM2500 marine Navy duty cycle using DL-1 type fuel. The prototype rig has been operated for a total of approximately 300 run hours. 60 hours of run time at pressures exceeding 13.6 atmospheres and temperatures exceeding 675 K. 12 hours of run time at pressures exceeding 15.3 atmospheres, temperatures exceeding 780 K. Over 700 data points were obtained. The assessment of the demonstrated performance revealed the prototype TVC test rig had exceeded all initial expectations. Demonstrated ignition, blow out, and altitude re-light were up to 50% improved over current technology conventional swirl stabilized combustors. NOx emissions were in the range from 40% to 60% of the 1996 ICAO standard. Combustion efficiency at or above 99% was maintained over a 40% wider operating range than a conventional combustor. The performance and operability achieved with this prototype test rig has clearly demonstrated the validity and potential performance payoffs of the TVC concept. This paper will summarize the TVC rectangular sector test rig configurations evaluated as part of this test program, and the performance and operability achieved.

Steady and Dynamic Performance and Emissions of a Variable Geometry Combustor in a Gas Turbine Engine

2002 ◽  
Author(s):  
Y. G. Li ◽  
R. L. Hales
Keyword(s):  
Gas Turbine ◽  
Dynamic Performance ◽  
Flame Temperature ◽  
Combustion Efficiency ◽  
Operating Conditions ◽  
Variable Geometry ◽  
Turbofan Engine ◽  
Turbine Engine ◽  
Control Schemes ◽  
Fuel Staging

One of the remedies to reduce the major emissions production of nitric oxide (NOx), carbon monoxide (CO) and unburned hydrocarbon (UHC) from conventional gas turbine engine combustors at both high and low operating conditions without losing its performance and stability is to use variable geometry combustors. This type of combustor configuration provides the possibility of dynamically controlling the airflow distribution of the combustor based on its operating conditions and therefore controlling the combustion in certain lean burn conditions. Two control schemes are described and analyzed in this paper: both are based on airflow control with variable geometry, the second including fuel staging. A model two-spool turbofan engine is chosen in this study to test the effectiveness of the variable geometry combustor and control schemes. The steady and dynamic performance of the turbofan engine is simulated and analyzed using an engine transient performance analysis code implemented with the variable geometry combustor. Empirical correlations for NOx, CO and UHC are used for the estimation of emissions. Some conclusions are obtained from this study: • With variable geometry combustors significant reduction of NOx emissions at high operating conditions and CO and UHC at low operating condition is possible; • Combustion efficiency and stability can be improved at low operating conditions, which is symbolized by the higher flame temperature in the variable geometry combustor; • The introduced correlation between non-dimensional fuel flow rate and air flow ratio to the primary zone is effective and simple in the control of flame temperature; • Circumferential fuel staging can reduce the range of air splitter movement in most of the operating conditions from idle to maximum power and have the great potential to reduce the inlet distortion to the combustor and improve the combustion efficiency; • During transient processes, the maximum moving rate of the hydraulic driven system may delay the air splitter movement but this effect on engine combustor performance is not significant.

Steady and Dynamic Performance and Emissions of a Variable Geometry Combustor in a Gas Turbine Engine

2003 ◽  
Vol 125 (4) ◽  
pp. 961-971 ◽  
Author(s):  
Y. G. Li ◽  
R. L. Hales
Keyword(s):  
Gas Turbine ◽  
Dynamic Performance ◽  
Flame Temperature ◽  
Combustion Efficiency ◽  
Operating Conditions ◽  
Variable Geometry ◽  
Turbofan Engine ◽  
Turbine Engine ◽  
Control Schemes ◽  
Fuel Staging

One of the remedies to reduce the major emissions production of nitric oxide NOx, carbon monoxide (CO), and unburned hydrocarbon (UHC) from conventional gas turbine engine combustors at both high and low operating conditions without losing performance and stability is to use variable geometry combustors. This type of combustor configuration provides the possibility of dynamically controlling the airflow distribution of the combustor based on its operating conditions and therefore controlling the combustion in certain lean burn conditions. Two control schemes are described and analyzed in this paper: Both are based on airflow control with variable geometry, the second including fuel staging. A model two-spool turbofan engine is chosen in this study to test the effectiveness of the variable geometry combustor and control schemes. The steady and dynamic performance of the turbofan engine is simulated and analyzed using an engine transient performance analysis code implemented with the variable geometry combustor. Empirical correlations for NOx, CO, and UHC are used for the estimation of emissions. Some conclusions are obtained from this study: (1) with variable geometry combustors significant reduction of NOx emissions at high operating conditions and CO and UHC at low operating condition is possible; (2) combustion efficiency and stability can be improved at low operating conditions, which is symbolized by the higher flame temperature in the variable geometry combustor; (3) the introduced correlation between nondimensional fuel flow rate and air flow ratio to the primary zone is effective and simple in the control of flame temperature; (4) circumferential fuel staging can reduce the range of air splitter movement in most of the operating conditions from idle to maximum power and have the great potential to reduce the inlet distortion to the combustor and improve the combustion efficiency; and (5) during transient processes, the maximum moving rate of the hydraulic driven system may delay the air splitter movement but this effect on engine combustor performance is not significant.

Compact Combustion Systems Using a Combination of Trapped Vortex and High-G Combustor Technologies

2008 ◽  
Author(s):  
J. Zelina ◽  
W. Anderson ◽  
P. Koch ◽  
D. T. Shouse
Keyword(s):  
High Performance ◽  
Combustion Efficiency ◽  
Operating Conditions ◽  
Fuel Injector ◽  
Flammability Limits ◽  
Turbine Engine ◽  
Lean Blowout ◽  
Wide Range ◽  
Combustion Systems ◽  
Trapped Vortex

Major advances in combustor technology are required to meet the conflicting challenges of improving performance, increasing durability and maintaining cost. Ultra-short combustors to minimize residence time, with special flame-holding mechanisms to cope with increased through-velocities are likely in the future. This paper focuses on vortex-stabilized combustor technologies that can enable the design of compact, high-performance combustion systems. Compact combustors weigh less and take up less volume in space-limited turbine engine for aero applications. This paper presents the UCC, a novel design based on TVC work that uses high swirl in a circumferential cavity to enhance mixing rates via high cavity g-loading on the order of 3000 g’s. The UCC design integrates compressor and turbine features which will enable a shorter and potentially less complex gas turbine engine. Ultimately, it is envisioned that this type of combustion system can be used as the main combustor and/or as a secondary combustor between the high pressure and low pressure turbine to operate as a reheat cycle engine. The focus on this paper includes experimental results of the UCC for a variety of conditions: (1) the addition of turbine vanes in the combustor flowpath, (2) a comparison of JP-8 and FT fuel performance in the combustor, (3) the use of trapped-vortex-like air addition to increase combustor flammability limits, and (4) combustor performance related to two different fuel injector designs. Lean blowout fuel-air ratio limits at 20% the value of current systems were demonstrated. Combustion efficiency was measured over a wide range of UCC operating conditions. This data begins to build the design space required for future engine designs that may use these novel, compact, high-g combustion systems.

Combustion Characteristics of Small Size Gas Turbine Combustor Fueled by Biomass Gas Employing Flameless Combustion

2007 ◽  
Author(s):  
Masato Hiramatsu ◽  
Yoshifumi Nakashima ◽  
Sadamasa Adachi ◽  
Yudai Yamasaki ◽  
Shigehiko Kaneko
Keyword(s):  
Gas Turbine ◽  
Combustion Efficiency ◽  
Combustion Characteristics ◽  
Operating Conditions ◽  
Nox Emissions ◽  
Gas Turbine Combustor ◽  
Flameless Combustion ◽  
Engine Exhaust ◽  
Micro Gas Turbine

One approach to achieving 99% combustion efficiency (C.E.) and 10 ppmV or lower NOx (at 15%O2) in a micro gas turbine (MGT) combustor fueled by biomass gas at a variety of operating conditions is with the use of flameless combustion (FLC). This paper compares experimentally obtained results and CHEMKIN analysis conducted for the developed combustor. As a result, increase the number of stage of FLC combustion enlarges the MGT operation range with low-NOx emissions and high-C.E. The composition of fuel has a small effect on the characteristics of ignition in FLC. In addition, NOx in the engine exhaust is reduced by higher levels of CO2 in the fuel.

Optimal State-Space Control of a Gas Turbine Engine

1992 ◽  
Vol 114 (4) ◽  
pp. 763-767 ◽  
Author(s):  
J. W. Watts ◽  
T. E. Dwan ◽  
C. G. Brockus
Keyword(s):  
State Space ◽  
Gas Turbine ◽  
State Space Model ◽  
Gas Turbine Engine ◽  
The State ◽  
Operating Conditions ◽  
Turbine Engine ◽  
Analog Control ◽  
Linear State ◽  
High Level

An analog fuel control for a gas turbine engine was compared with several state-space derived fuel controls. A single-spool, simple cycle gas turbine engine was modeled using ACSL (high level simulation language based on FORTRAN). The model included an analog fuel control representative of existing commercial fuel controls. The ACSL model was stripped of nonessential states to produce an eight-state linear state-space model of the engine. The A, B, and C matrices, derived from rated operating conditions, were used to obtain feedback control gains by the following methods: (1) state feedback; (2) LQR theory; (3) Bellman method; and (4) polygonal search. An off-load transient followed by an on-load transient was run for each of these fuel controls. The transient curves obtained were used to compare the state-space fuel controls with the analog fuel control. The state-space fuel controls did better than the analog control.

The Effect of Heat Transfer Coefficient Increase on Tip Clearance Control in H.P. Compressors in Gas Turbine Engine

2013 ◽  
Author(s):  
Godwin Ita Ekong ◽  
Christopher A. Long ◽  
Peter R. N. Childs
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Gas Turbine ◽  
Time Constant ◽  
Gas Turbine Engine ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Test Facility ◽  
Turbine Engine

Compressor tip clearance for a gas turbine engine application is the radial gap between the stationary compressor casing and the rotating blades. The gap varies significantly during different operating conditions of the engine due to centrifugal forces on the rotor and differential thermal expansions in the discs and casing. The tip clearance in the axial flow compressor of modern commercial civil aero-engines is of significance in terms of both mechanical integrity and performance. In general, the clearance is of critical importance to civil airline operators and their customers alike because as the clearance between the compressor blade tips and the casing increases, the aerodynamic efficiency will decrease and therefore the specific fuel consumption and operating costs will increase. This paper reports on the development of a range of concepts and their evaluation for the reduction and control of tip clearance in H.P. compressors using an enhanced heat transfer coefficient approach. This would lead to improvement in cruise tip clearances. A test facility has been developed for the study at the University of Sussex, incorporating a rotor and an inner shaft scaled down from a Rolls-Royce Trent aero-engine to a ratio of 0.7:1 with a rotational speed of up to 10000 rpm. The idle and maximum take-off conditions in the square cycle correspond to in-cavity rotational Reynolds numbers of 3.1×106 ≤ Reφ ≤ 1.0×107. The project involved modelling of the experimental facilities, to demonstrate proof of concept. The analysis shows that increasing the thermal response of the high pressure compressor (HPC) drum of a gas turbine engine assembly will reduce the drum time constant, thereby reducing the re-slam characteristics of the drum causing a reduction in the cold build clearance (CBC), and hence the reduction in cruise clearance. A further reduction can be achieved by introducing radial inflow into the drum cavity to further increase the disc heat transfer coefficient in the cavity; hence a further reduction in disc drum time constant.

scholarly journals Comprehensive report on Materials for Gas Turbine Engine Components

2019 ◽  
Vol 9 (2S2) ◽  
pp. 155-158
Keyword(s):  
Gas Turbine ◽  
Turbine Blade ◽  
Thermal Stresses ◽  
Prolonged Exposure ◽  
Raw Materials ◽  
Turbine Blades ◽  
Gas Turbine Engine ◽  
Operating Conditions ◽  
Turbine Engine ◽  
Engine Component

In the past three decades, it is very challenging for the researchers to design and development a best gas turbine engine component. Engine component has to face different operating conditions at different working environments. Nickel based superalloys are the best material to design turbine components. Inconel 718, Inconel 617, Hastelloy, Monel and Udimet are the common material used for turbine components. Directional solidification is one of the conventional casting routes followed to develop turbine blades. It is also reported that the raw materials are heat treated / age hardened to enrich the desired properties of the material implementation. Accordingly they are highly susceptible to mechanical and thermal stresses while operating. The hot section of the turbine components will experience repeated thermal stress. The halides in the combination of sulfur, chlorides and vanadate are deposited as molten salt on the surface of the turbine blade. On prolonged exposure the surface of the turbine blade starts to peel as an oxide scale. Microscopic images are the supportive results to compare the surface morphology after complete oxidation / corrosion studies. The spectroscopic results are useful to identify the elemental analysis over oxides formed. The predominant oxides observed are NiO, Cr2O3, Fe2O3 and NiCr2O4. These oxides are vulnerable on prolonged exposure and according to PB ratio the passivation are very less. In recent research, the invention on nickel based superalloys turbine blades produced through other advanced manufacturing process is also compared. A summary was made through comparing the conventional material and advanced materials performance of turbine blade material for high temperature performance.

Development of Dry Low-NOx Combustor for 300 kW Class Gas Turbine Applied to Co-Generation Systems

2001 ◽  
Author(s):  
Yoichiro Ohkubo ◽  
Osamu Azegami ◽  
Hiroshi Sato ◽  
Yoshinori Idota ◽  
Shinichiro Higuchi
Keyword(s):  
Gas Turbine ◽  
Output Power ◽  
Combustion Efficiency ◽  
Gas Generator ◽  
Turbine Engine ◽  
Partial Load ◽  
Wide Range ◽  
Compressor Inlet ◽  
Endurance Testing ◽  
Turbine Speed

A 300 kWe class gas turbine which has a two-shaft and simple-cycle has been developed to apply to co-generation systems. The gas turbine engine is operated in the range of about 30% partial load to 100% load. The gas turbine combustor requires a wide range of stable operations and low NOx characteristics. A double staged lean premixed combustor, which has a primary combustion duct made of Si3N4 ceramics, was developed to meet NOx regulations of less than 80 ppm (corrected at 0% oxygen). The gas turbine with the combustor has demonstrated superior low-emission performance of around 40 ppm (corrected at 0% oxygen) of NOx, and more than 99.5% of combustion efficiency between 30% and 100% of engine load. Endurance testing has demonstrated stable high combustion performance over 3,000 hours in spite of a wide compressor inlet air temperature (CIT) range of 5 to 35 degree C.. While increasing the gas generator turbine speed, the flow rate of primary fuel was controlled to hold a constant equivalence ratio of around 0.5 in the CIT range of more than 15 C. The output power was also decreased while increasing the CIT, in order to keep a constant temperature at the turbine inlet. The NOx decreases in the CIT range of more than 15 C. On the other hand, the NOx increases in the CIT range of less than 15 C when the output power was kept a constant maximum power. As a result, NOx emission has a peak value of about 40 ppm at 15 C.

Method for calculating the thrust and specific thrust of a double-flow gas turbine engine based on the results of tests at the laboratory unit «Flame»

2021 ◽  
pp. 58-64
Author(s):  
S.M. Sergeev ◽  
◽  
V.A. Kudriashov ◽  
N.V. Petrukhin ◽  
◽  
...  
Keyword(s):  
Gas Turbine ◽  
Gas Turbine Engine ◽  
Operating Conditions ◽  
Similarity Criteria ◽  
Fuel Quality ◽  
Jet Engines ◽  
Laboratory Unit ◽  
Turbine Engine ◽  
Specific Thrust ◽  
The Cost

The main technical characteristics of jet engines depend on the fuel quality: thrust and fuel consumption. As a rule, the comparative assessment of real engines is carried by specific values. Specific thrust is one of the most important parameters of the gas turbine engine (GTE). The larger it is, the smaller the required air flow rate through the engine at a given thrust and therefore its dimensions and mass. To date, a system for evaluating the performance properties of fuels based on qualification methods has been created. However, these methods do not allow calculating the thrust and specific thrust of the engine and potentially assessing the effect of fuels on these characteristics. Therefore, the issues of efficient use of fuels for GTE are solved almost exclusively on the basis of tests at testing units with full-scale engines, which are carried out repeatedly, which leads to a significant increase in the cost of testing. The article proposes a method for calculating the thrust and specific thrust of a double-flow gas turbine engine according to the results of tests at a constant volume laboratory unit of bypass type “Flame”. The method is based on modeling the engine operating conditions using the similarity criteria of the bench reactor and the real engine and allows reducing significantly the material and time costs for testing. The experimental of the combustion characteristics of hydrocarbon fuels and the rated values of their thrust and specific thrust for a double-flow gas turbine engine are presented.

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