scholarly journals Further Development of an Improved Pulse, Pressure Gain, Gas-Turbine Combustor

1990 ◽  
Author(s):  
J. A. C. Kentfield ◽  
L. C. V. Fernandes
Keyword(s):  
Secondary Flow ◽  
Steady Flow ◽  
Gas Turbine ◽  
Pulse Pressure ◽  
Gas Turbines ◽  
Gas Generator ◽  
Pulse Combustor ◽  
Analytical Work ◽  
Further Development ◽  
Flow Duct

Further development work is described, which included both theoretical analysis and experimental testing, of an improved prototype, valveless, pulse, pressure gain, combustor for gas turbines. The analytical work involved the application to the non-steady flow in the combustor secondary flow duct of the method-of-characteristics as used for one-space dimensional, time dependent, compressible flows. Gas temperatures in the secondary flow duct were measured experimentally as were the pressure gain, due to the pulse combustor, and the overall efficiencies of the gas generator type gas-turbine with both the conventional steady flow combustor and the alternative pulse, pressure gain, combustor. It was concluded that the analytical work confirmed earlier experimental findings showing the benefits of restricting the secondary flow duct exit area. It was also concluded that the use of the pulse combustor resulted in a maximum improvement of 27% in the thermal efficiency of the small, low pressure-ratio, educational, gas generator turbo-machine.

A Multiple-Inlet Core for Gas Turbine, Pulse, Pressure-Gain Combustors

1991 ◽  
Author(s):  
J. A. C. Kentfield ◽  
B. C. Speirs
Keyword(s):  
Gas Turbine ◽  
Pulse Pressure ◽  
Gas Turbines ◽  
Pressure Rise ◽  
Stagnation Pressure ◽  
Maximum Increase ◽  
Pulse Combustor ◽  
Delivery Pressure ◽  
Time Required ◽  
Volumetric Loading

Prior tests showed that a maximum increase of stagnation pressure equal to 4% of the compressor absolute delivery pressure was obtained on a very small gas turbine equipped with a prototype, valveless, pulse, pressure-gain, combustor. Accordingly, a new core pulse-combustor has been developed for a proposed pulse, pressure-gain, combustor for larger, more representative, gas turbines. The new core pulse-combustor differs from the earlier prototype design in that the single inlet passage has been replaced with four parallel inlet passages. It is shown that this concept reduces the time required for pre-combustion mixing of the air, fuel and products in the combustion zone. This results in the overall length of the combustor being reduced to about 60% of that required for a single inlet design. It was concluded, on the basis of tests, that a pulse, pressure-gain, combustor incorporating the new core unit should be capable of generating a maximum stagnation pressure-rise of about 10% of the compressor delivery pressure with a volumetric loading 3 to 4 times that of the original prototype.

Capacity Matching of Aeroderivative Gas Generator With Free Power Turbine: Challenges, Uncertainties, and Opportunities

2019 ◽  
Author(s):  
Deepak Thirumurthy ◽  
Jose Carlos Casado Coca ◽  
Kanishka Suraweera
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Systems Approach ◽  
Gas Generator ◽  
Performance Guarantees ◽  
Design Variables ◽  
Performance Trends ◽  
Power Turbine ◽  
Parameter Matching ◽  
Turbine Capacity

Abstract For gas turbines with free power turbines, the capacity or flow parameter matching is of prime importance. Accurately matched capacity enables the gas turbine to run at its optimum conditions. This ensures maximum component efficiencies, and optimum shaft speeds within mechanical limits. This paper presents the challenges, uncertainties, and opportunities associated with an accurate matching of a generic two-shaft aeroderivative HP-LP gas generator with the free power turbine. Additionally, generic performance trends, uncertainty quantification, and results from the verification program are also discussed. These results are necessary to ensure that the final free power turbine capacity is within the allowable range and hence the product meets the performance guarantees. The sensitivity of free power turbine capacity to various design variables such as the vane throat area, vane trailing edge size, and manufacturing tolerance is presented. In addition, issues that may arise due to not meeting the target capacity are also discussed. To conclude, in addition to design, analysis, and statistical studies, a system-of-systems approach is mandatory to meet the allowed variation in the free power turbine capacity and hence the desired gas turbine performance.

Off-design performance improvement of twin-shaft gas turbine by variable geometry turbine and compressor besides fuel control

2019 ◽  
Vol 234 (7) ◽  
pp. 957-980
Author(s):  
Sepehr Sanaye ◽  
Salahadin Hosseini
Keyword(s):  
Life Cycle ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Guide Vane ◽  
Design Parameters ◽  
Inlet Guide Vane ◽  
Inlet Temperature ◽  
Gas Generator ◽  
Turbine Inlet ◽  
Exit Temperature

A novel procedure for finding the optimum values of design parameters of industrial twin-shaft gas turbines at various ambient temperatures is presented here. This paper focuses on being off design due to various ambient temperatures. The gas turbine modeling is performed by applying compressor and turbine characteristic maps and using thermodynamic matching method. The gas turbine power output is selected as an objective function in optimization procedure with genetic algorithm. Design parameters are compressor inlet guide vane angle, turbine exit temperature, and power turbine inlet nozzle guide vane angle. The novel constrains in optimization are compressor surge margin and turbine blade life cycle. A trained neural network is used for life cycle estimation of high pressure (gas generator) turbine blades. Results for optimum values for nozzle guide vane/inlet guide vane (23°/27°–27°/6°) in ambient temperature range of 25–45 ℃ provided higher net power output (3–4.3%) and more secured compressor surge margin in comparison with that for gas turbines control by turbine exit temperature. Gas turbines thermal efficiency also increased from 0.09 to 0.34% (while the gas generator turbine first rotor blade creep life cycle was kept almost constant about 40,000 h). Meanwhile, the averaged values for turbine exit temperature/turbine inlet temperature changed from 831.2/1475 to 823/1471°K, respectively, which shows about 1% decrease in turbine exit temperature and 0.3% decrease in turbine inlet temperature.

Improvements to the Performance of a Prototype Pulse, Pressure-Gain, Gas Turbine Combustor

1990 ◽  
Vol 112 (1) ◽  
pp. 67-72 ◽  
Author(s):  
J. A. C. Kentfield ◽  
L. C. V. Fernandes
Keyword(s):  
Secondary Flow ◽  
Gas Turbine ◽  
Pulse Pressure ◽  
Path Length ◽  
Flow Path ◽  
Maximum Pressure ◽  
Gas Turbine Combustor ◽  
Flow Passage ◽  
Delivery Pressure ◽  
Flow Path Length

A description is given of a simple, prototype, pulse, pressure-gain combustor for a gas turbine. The work reported was targeted at alleviating problems previously observed with the prototype combustor. These were related to irreversibilities, causing a performance deficiency, in the secondary flow passage. The work consisted of investigating experimentally the effect of tuning the secondary-flow path length, adding a flow restrictor at the combining-cone entry station, and redesigning the combining cone itself. The overall result was to eradicate the previously noted performance deficiency, thereby increasing the maximum pressure gain obtained in the gas turbine from 1.6 to 4.0 percent of the compressor absolute delivery pressure.

Three-Dimensional Time-Resolved Flow Field in the First and Last Turbine Stage of a Heavy Duty Gas Turbine: Part I — Secondary Flow Field

2000 ◽  
Author(s):  
Martin von Hoyningen-Huene ◽  
Wolfram Frank ◽  
Alexander R. Jung
Keyword(s):  
Flow Field ◽  
Secondary Flow ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Companion Paper ◽  
Heavy Duty ◽  
Turbine Stage ◽  
Time Resolved ◽  
Heavy Duty Gas Turbine ◽  
Secondary Flow Field

Unsteady stator-rotor interaction in gas turbines has been investigated both experimentally and numerically for some years now. Even though the numerical methods are still in development, today they have reached a certain degree of maturity allowing industry to focus on the results of the computations and their impact on turbine design, rather than on a further improvement of the methods themselves. The key to increase efficiency in modern gas turbines is a better understanding and subsequent optimization of the loss-generation mechanisms. A major part of these are the secondary losses. To this end, this paper presents the time-resolved secondary flow field for the two test cases computed, viz the first and the last turbine stage of a modern heavy duty gas turbine. A companion paper referring to the same computations focuses on the unsteady pressure fluctuations on vanes and blades. The investigations have been performed with the flow solver ITSM3D which allows for efficient calculations that simulate the real blade count ratio. This is a prerequisite to simulate the unsteady phenomena in frequency and amplitude properly.

scholarly journals Development of a High Pressure Ratio Centrifugal Compressor for 300kW-Class Ceramic Gas Turbine

1997 ◽  
Author(s):  
T. Sakai ◽  
Y. Tohbe ◽  
T. Fujii ◽  
T. Tatsumi
Keyword(s):  
Research And Development ◽  
Gas Turbine ◽  
Gas Turbines ◽  
High Efficiency ◽  
Pressure Ratio ◽  
Flow Distribution ◽  
Leading Edge ◽  
Inlet Temperature ◽  
Angle Distribution ◽  
Gas Generator

Research and development of ceramic gas turbines (CGT), which is promoted by the Japanese Ministry of International Trade and Industry (MITI), was started in 1988. The target of the CGT project is development of a 300kW-class ceramic gas turbine with a 42 % thermal efficiency and a turbine inlet temperature (TIT) of 1350°C. Two types of CGT engines are developed in this project. One of the CGT engines, which is called CGT302, is a recuperated two-shaft gas turbine with a compressor, a gas-generator turbine, and a power turbine for cogeneration. In this paper, we describe the research and development of a compressor for the CGT302. Specification of this compressor is 0.89 kg/sec air flow rate and 8:1 pressure ratio. The intermediary target efficiency is 78% and the final target efficiency is 82%, which is the highest level in email centrifugal compressors like this one. We measured impeller inlet and exit flow distribution using three-hole yaw probes which were traversed from the shroud to the hub. Based on the measurement of the impeller exit flow, diffusers with a leading edge angle distribution adjusted to the inflow angle were designed and manufactured. Using this diffuser, we were able to attain a high efficiency (8:1 pressure ratio and 78% adiabatic efficiency).

Theoretical and Practical Aspects of the Application of Resonant Combustion Chambers in Gas Turbines

1971 ◽  
Vol 13 (3) ◽  
pp. 137-150 ◽  
Author(s):  
J. L. Muller
Keyword(s):  
Gas Turbine ◽  
Experimental Work ◽  
Gas Turbines ◽  
Specific Power ◽  
Combustion Chambers ◽  
Piston Cylinder ◽  
Turbine Performance ◽  
Specific Power Output ◽  
Pressure Gain Combustion ◽  
Further Development

This paper discusses theoretical and experimental work carried out to determine the feasibility of a pressure-gain combustion system for gas turbines. Fundamental principles involved in the design of resonant combustors are considered and potential improvements in gas turbine performance are calculated by means of a piston-cylinder analogy. The results indicate that significant improvements in overall thermal efficiency and specific power output can be expected at relatively low pressure ratios but that these improvements become less effective at higher pressure ratios due to the influence of increased compressor delivery temperatures. The results of experimental work on a multiple combustor configuration show that the theoretical performance appears to be attainable and that, subject to further development work, resonant combustion chambers could be utilized to improve gas turbine performance.

scholarly journals Development and Fabrication of Ceramic Gas Turbine Components

1996 ◽  
Author(s):  
Koichi Tanaka ◽  
Sazo Tsuruzono ◽  
Toshifumi Kubo ◽  
Makoto Yoshida
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Elevated Temperatures ◽  
Rupture Strength ◽  
High Stress ◽  
Stress Rupture ◽  
Inlet Temperature ◽  
Gas Generator ◽  
Rotating Speed ◽  
Ceramic Components

Kyocera has been developing various ceramic components for gas turbines under the Ceramic Gas Turbine (CGT) Project funded by the Japanese Government. This project has set a turbine inlet temperature (TIT) of 1350°C as a final target. For 1350°C TIT, we have developed a new silicon nitride material SN281, which has high stress rupture strength at elevated temperatures up to 1500°C. This material has excellent oxidation resistance as well. We have also developed improved sintering and inspection technologies for the use of SN281 as engine components. We are able to fabricate rotors and nozzles of the gas generator turbine (GGT) in good agreement with design geometry requirements, by optimizing sintering conditions. Small defects were also successfully detected by microfocus X-ray radiography. The SN281 rotors have attained 120% of design rotating speed at room temperature.

scholarly journals Pulsating Combustion Applied to a Small Gas Turbine

1985 ◽  
Author(s):  
J. A. C. Kentfield ◽  
P. Yerneni
Keyword(s):  
Steady Flow ◽  
Gas Turbine ◽  
Stagnation Pressure ◽  
Combustion System ◽  
Gas Generator ◽  
Future Developments ◽  
Turbine Inlet ◽  
Generator Type ◽  
Improved Performance ◽  
To Receive

A description is given of, what is believed to be the first test ever made of a gas turbine in which a valveless pulsed combustor replaced the conventional steady flow combustor. It is explained that the main incentive for using a pulsed combustor in a gas turbine is to achieve a net stagnation pressure gain between the compressor outlet and the turbine inlet. Brief descriptions are given of the pulsed combustor and the adaptation of the small gas turbine, which was of the gas generator type, to receive the pulsating combustion system. Results are presented which show that the gas turbine operated successfully using the pulsed combustor and that a very small net stagnation-pressure gain was achieved. An indication is given of possible future developments which should result in improved performance.

scholarly journals Thermomechanical Advances for Small Gas Turbine Engines: Present Capabilities and Future Direction in Gas Generator Designs

1988 ◽  
Author(s):  
M. Propen ◽  
H. Vogel ◽  
S. Aksoy
Keyword(s):  
Gas Turbine ◽  
Broad Spectrum ◽  
Gas Turbines ◽  
Weight Ratio ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Gas Generator ◽  
Performance Requirements ◽  
Materials Research ◽  
Future Direction

Performance requirements of tomorrow’s gas turbines demand major improvements in specific fuel consumption and thrust to weight ratio. These stringent requirements, in turn, drive the need for higher operating temperatures and lighter weight engines. Such technical improvements impose severe thermal, structural, and metallurgical demands upon turbine components. A broad spectrum of technology programs is underway at Textron Lycoming to address these challenging requirements. This paper outlines the thermal, structural, and materials research needed for achieving the goals of the small gas turbines of tomorrow.

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