scholarly journals Approximately Calculating Optimum Pressure Ratios for Various Gas Turbine Cycles

1976 ◽  
Author(s):  
I. J. Ushiyama ◽  
N. Matsumoto
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Gas Turbine Engine ◽  
Point Of View ◽  
Numerical Calculations ◽  
Optimum Pressure ◽  
Turbine Engine ◽  
Specific Output

In designing the gas turbine engine, it is important to know the rough relationship between the specific output, thermal efficiency, and pressure ratios before setting about calculating the practical cycle. In general, the specific output and the thermal efficiency have their maximum values at certain pressure ratios. The pressure ratios for these maximum values, however, differ in the case of the specific output from the thermal efficiency even in the same type of gas turbine. This paper presents the equations for the optimum pressure ratios of the specific output and thermal efficiency which are obtained for seven types of single-shaft gas turbines. Furthermore, a change in the forms of the curves is made clear by the numerical calculations for the specific output and thermal efficiency near the range of optimum pressure ratios. From the results of this paper, the optimum pressure ratios for every type of single-shaft gas turbine can be easily determined from the thermodynamical point of view.

Improving Gas Turbine Performance Through Reassembling Degraded Components: An Experimental and Computational Study

2020 ◽  
Author(s):  
Shuocheng Xia ◽  
Zhongran Chi ◽  
Shusheng Zang ◽  
Hui Wang
Keyword(s):  
Gas Turbine ◽  
Test Data ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Computational Study ◽  
Low Cost ◽  
Gas Turbine Engine ◽  
Performance Degradation ◽  
Turbine Engine ◽  
Turbine Performance

Abstract Performance degradation of gas turbine is a common phenomenon during operation. Maintenance of the degraded gas turbines and improving their performance at a low cost are important in engineering. In this paper, the maintenance method based on reassembling degraded components of existing gas turbines was studied. This research was based on a type of 2MW gas turbine engine. Blue ray scanning was carried out to rebuild the 3D flow-path geometries of the compressor and turbine of a degraded engine. Then CFD simulations were carried out to compare the characteristic maps of new and degraded components. Secondly, performance tests of six engines were carried out. A correction method was developed to get the specific component characteristics using test data, which can also analyze and quantify the degradations. Also, a gas turbine performance prediction program was used to find the promising component-exchange plan within 5 given gas turbines to improve total thermal efficiency. Finally, additional test was carried out to verify the performance of the reassembled gas turbine. Through the developed method including 3D scanning, CFD simulation, and correction of component characteristics with engine test data, the component performance degradation of a specific gas turbine can be obtained in quantity. The gas turbine performance predictions based on the acquired characteristic maps showed good agreement with test data. With the help of the method developed in this work, a new gas turbine engine was obtained through exchanging the components of degraded engines, which is at a very low cost and in a short time. The improvement in total thermal efficiency was about 0.3 percentage, which was verified by engine tests.

scholarly journals Comparison of Coriolis and Turbine Type Flow Meters for Fuel Measurement in Gas Turbine Testing

1993 ◽  
Author(s):  
J. D. MacLeod ◽  
W. Grabe
Keyword(s):  
Steady State ◽  
Gas Turbine ◽  
Mass Flow ◽  
Gas Turbines ◽  
Gas Turbine Engine ◽  
Turbine Engine ◽  
Turbine Flowmeter ◽  
Turbine Performance ◽  
Coriolis Flowmeter ◽  
Project Objectives

The Machinery and Engine Technology (MET) Program of the National Research Council of Canada (NRCC) has established a program for the evaluation of sensors to measure gas turbine engine performance accurately. The precise measurement of fuel flow is an essential part of steady-state gas turbine performance assessment. Prompted by an international engine testing and information exchange program, and a mandate to improve all aspects of gas turbine performance evaluation, the MET Laboratory has critically examined two types of fuel flowmeters, Coriolis and turbine. The two flowmeter types are different in that the Coriolis flowmeter measures mass flow directly, while the turbine flowmeter measures volumetric flow, which must be converted to mass flow for conventional performance analysis. The direct measurement of mass flow, using a Coriolis flowmeter, has many advantages in field testing of gas turbines, because it reduces the risk of errors resulting from the conversion process. Turbine flowmeters, on the other hand, have been regarded as an industry standard because they are compact, rugged, reliable, and relatively inexpensive. This paper describes the project objectives, the experimental installation, and the results of the comparison of the Coriolis and turbine type flowmeters in steady-state performance testing. Discussed are variations between the two types of flowmeters due to fuel characteristics, fuel handling equipment, acoustic and vibration interference and installation effects. Also included in this paper are estimations of measurement uncertainties for both types of flowmeters. Results indicate that the agreement between Coriolis and turbine type flowmeters is good over the entire steady-state operating range of a typical gas turbine engine. In some cases the repeatability of the Coriolis flowmeter is better than the manufacturers specification. Even a significant variation in fuel density (10%), and viscosity (300%), did not appear to compromise the ability of the Coriolis flowmeter to match the performance of the turbine flowmeter.

Low Emission Variable Area Combustor for Vehicular Gas Turbines

1973 ◽  
Vol 95 (3) ◽  
pp. 191-198 ◽  
Author(s):  
D. J. White ◽  
P. B. Roberts ◽  
W. A. Compton
Keyword(s):  
Power Systems ◽  
Gas Turbine ◽  
Environmental Protection Agency ◽  
Gas Turbines ◽  
Gas Turbine Engine ◽  
Protection Agency ◽  
Engine Emissions ◽  
Turbine Engine ◽  
Automotive Engine ◽  
Low Emission

In recent years automotive engine emissions have become subject to stringent Federal legislation. The most severe of these regulations pertains to the 1976 Emission Standards as defined by the Advanced Automotive Power Systems (AAPS) Division of the Environmental Protection Agency (EPA). A unique combustor concept has been developed by Solar which has demonstrated the feasibility of meeting these emission requirements. The integrated emissions of a typical regenerative gas turbine engine employing this combustor type were each below one half of the levels specified by the Federal 1976 Standards, when tested over a simulated federal driving cycle. The success of the feasibility tests for this combustor concept has lead to more fundamental studies and the planned development of a prototype combustor for demonstration on the EPA-AAPS baseline gas turbine engine. The prototype combustor for the baseline engine is described together with its variable area port mechanisms, which has been demonstrated as necessary for emission control.

On the Economics of the Use of Biomass Fuels in Gas Turbine Cycles: Gasification vs. Externally Firing

2004 ◽  
Author(s):  
Sandro Barros Ferreira ◽  
Pericles Pilidis
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Technological Development ◽  
Pilot Scale ◽  
Combined Cycle ◽  
Point Of View ◽  
Turbine Engine ◽  
Current Technology ◽  
Integrated Gasification

The use of biomass as gas turbine combined cycle fuels is broadly seen as one of the alternatives to diminish greenhouse gas emissions, mainly CO2, due to the efficiency delivered by such systems and the renewable characteristic of biomass itself. Integrated gasification cycles, BIGGT, are the current technology available; however the gasification system severely penalizes the power plant in terms of efficiency and demands modifications in the engine to accommodate the large fuel mass flow. This gives an opportunity to improvements in the current technologies and implementation of new ones. This paper intends to analyze new alternatives to the use of solid fuels in gas turbines, from the economical point of view, through the use of external combustion, EFGT, discussing its advantages and limitations over the current technology. The results show that both EFGT and BIGGT technologies are economically competitive with the current natural gas fired gas turbines. However, BIGGT power plants are still in pilot scale and the EFGT plants need further technological development. Thermodynamically speaking, the inherently recuperative characteristic of the EFGT gas turbine engine makes it well suited to the biomass market. The thermal efficiency of this cycle is higher than the BIGGT system. Furthermore, its fuel flexibility and negligible pre-treatmet is another advantage that makes it an interesting option for the Brazilian market.

Exploration of Compact Combustors for Reheat Cycle Aero Engine Applications

2006 ◽  
Author(s):  
J. Zelina ◽  
D. T. Shouse ◽  
J. S. Stutrud ◽  
G. J. Sturgess ◽  
W. M. Roquemore
Keyword(s):  
Gas Turbine ◽  
Temperature Rise ◽  
Gas Turbines ◽  
Gas Turbine Engine ◽  
Operating Conditions ◽  
Combustion System ◽  
Turbine Engine ◽  
Lean Blowout ◽  
Power Extraction ◽  
Wide Range

An aero gas turbine engine has been proposed that uses a near-constant-temperature (NCT) cycle and an Inter-Turbine Burner (ITB) to provide large amounts of power extraction from the low-pressure turbine. This level of energy is achieved with a modest temperature rise across the ITB. The additional energy can be used to power a large geared fan for an ultra-high bypass ratio transport aircraft, or to drive an alternator for large amounts of electrical power extraction. Conventional gas turbines engines cannot drive ultra-large diameter fans without causing excessively high turbine temperatures, and cannot meet high power extraction demands without a loss of engine thrust. Reducing the size of the combustion system is key to make use of a NCT gas turbine cycle. Ultra-compact combustor (UCC) concepts are being explored experimentally. These systems use high swirl in a circumferential cavity about the engine centerline to enhance reaction rates via high cavity g-loading on the order of 3000 g’s. Any increase in reaction rate can be exploited to reduce combustor volume. The UCC design integrates compressor and turbine features which will enable a shorter and potentially less complex gas turbine engine. This paper will present experimental data of the Ultra-Compact Combustor (UCC) performance in vitiated flow. Vitiation levels were varied from 12–20% oxygen levels to simulate exhaust from the high pressure turbine (HPT). Experimental results from the ITB at atmospheric pressure indicate that the combustion system operates at 97–99% combustion efficiency over a wide range of operating conditions burning JP-8 +100 fuel. Flame lengths were extremely short, at about 50% of those seen in conventional systems. A wide range of operation is possible with lean blowout fuel-air ratio limits at 25–50% below the value of current systems. These results are significant because the ITB only requires a small (300°F) temperature rise for optimal power extraction, leading to operation of the ITB at near-lean-blowout limits of conventional combustor designs. This data lays the foundation for the design space required for future engine designs.

Experimental Results of Hot Section Metal Temperature Measurements of Rolls-Royce Allison 501KH Under Massive Steam Injection

2002 ◽  
Author(s):  
Dah Yu Cheng ◽  
Albert L. C. Nelson
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Steam Injection ◽  
Gas Turbine Engine ◽  
Injection Rate ◽  
Experimental Results ◽  
Turbine Engine ◽  
Second Stage ◽  
Before And After ◽  
Internally Cooled

It has always been thought by the gas turbine industry that steam injection will shorten the effective life of certain gas turbine parts. Recently it was shown that a number of steam injected Cheng Cycle Rolls-Royce Allison 501KH gas turbines, accumulated more than 2.5 million logged hours of operation and with a prolonged parts life. The “hot parts” of a Rolls-Royce Allison 501KH gas turbine engine that are of concern, are the first stage nozzle, the first stage blade, and the second stage nozzle. These parts are all air cooled through the first stages internal passages. (The second stage blades and on down are not internally cooled.) The concern raised in many gas turbine institutions is that the metal temperatures of these hot parts, due to the heat conductivity properties of injected steam, will make them deteriorate faster. An experiment was completed using a steam injected Cheng Cycle, on an Allison 501KH gas turbine engine. In the experiment, a substantial number of thermocouples were attached to the surfaces of the turbines hot parts. This engine had a steam injection rate of up to 18% airflow. The experimental results showed that if steam could be properly mixed with the cooling air before the air enters into the cooling passages of the hot parts, the metal temperatures did not increase. During the operation of the engines, it was recorded that the hot parts lifetime increased from 25,000 hours before the hot parts section had to be overhauled, to 42,000 hours (on average) before they needed to be overhauled. This paper will report the measurement installation in detail. The results before and after steam injection in the hot parts sections of the Rolls-Royce Allison 501KH engine will also be discussed.

scholarly journals Optimization of a Multistage Axial Compressor in a Gas Turbine Engine System

1992 ◽  
Author(s):  
I. N. Egorov
Keyword(s):  
Gas Turbine ◽  
Operation Mode ◽  
Axial Compressor ◽  
Gas Turbine Engine ◽  
Point Of View ◽  
Design Parameters ◽  
Turbine Engine ◽  
Non Linear Programming ◽  
Fan Blade ◽  
Multistage Axial Compressor

The work presents a procedure to determine the design parameters of multistage axial compressor (MAC) rows, the parameters optimum from the point of view to assure the best integrated indices of gas turbine engine (GTE) both at the design and off-design operation mode. Effectiveness of the proposed approach has been demonstrated with regards to solving the problems of optimum contouring by the radius of 7 rows of 4-stage fan included in a two-shaft turbofan. For the examples under consideration respective problems of non-linear programming have been set whose dimensionality reached up to 63 of the design parameters of fan blade rows. It is shown, that the requirement to provide the best engine characteristics, integrated matching both GTE component parts (in our case these are compressor blade rows) and integrated characteristics of components included in an engine is of more importance than assuring the highest efficiency of separate components under consideration.

Technological Trend of Aircraft Gas Turbines and its Effect on the Development for Ship Propulsion Plants

1970 ◽  
Author(s):  
N. K. H. Scholz
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Gas Turbine Engine ◽  
Design Parameters ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Compression Pressure ◽  
Turbine Engine ◽  
Ship Propulsion

The effect of the main design parameters of the aero gas turbine engine cycle, namely combustion temperature and compression pressure ratio, on the specific performance values is discussed. The resulting development trend has been of essential influence on the technology. Relevant approaches are outlined. The efforts relating to weight and manufacturing expense are also indicated. In the design of aero gas turbine engines increasing consideration is given to the specific flight mission requirements, such as for instance by the introduction of the by-pass principle. Therefore direct application of aero gas turbine engines for ship propulsion without considerable modifications, as has been practiced in the past, is not considered very promising for the future. Nevertheless, there are possibilities to take advantage of aero gas turbine engine developments for ship propulsion systems. Appropriate approaches are discussed. With the experience obtained from aero gas turbine engines that will enter service in the early seventies it should be possible to develop marine gas turbine engines achieving consumptions and lifes that are competitive with those of advanced diesel units.

scholarly journals Prediction and Analysis of Impact of Thermal Barrier Coating Oxidation on Gas Turbine Creep Life

2016 ◽  
Vol 138 (12) ◽  
Author(s):  
E. A. Ogiriki ◽  
Y. G. Li ◽  
Th. Nikolaidis
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Gas Turbine Engine ◽  
Operating Conditions ◽  
Thermal Barrier ◽  
Creep Life ◽  
Premature Failure ◽  
Turbine Engine ◽  
Oxidation Rates ◽  
The Impact

Thermal barrier coatings (TBCs) have been widely used in the power generation industry to protect turbine blades from damage in hostile operating environment. This allows either a high turbine entry temperature (TET) to be employed or a low percentage of cooling air to be used, both of which will improve the performance and efficiency of gas turbine engines. However, with continuous increases in TET aimed at improving the performance and efficiency of gas turbines, TBCs have become more susceptible to oxidation. Such oxidation has been largely responsible for the premature failure of most TBCs. Nevertheless, existing creep life prediction models that give adequate considerations to the effects of TBC oxidation on creep life are rare. The implication is that the creep life of gas turbines may be estimated more accurately if TBC oxidation is considered. In this paper, a performance-based integrated creep life model has been introduced with the capability of assessing the impact of TBC oxidation on the creep life and performance of gas turbines. The model comprises of a thermal, stress, oxidation, performance, and life estimation models. High pressure turbine (HPT) blades are selected as the life limiting component of gas turbines. Therefore, the integrated model was employed to investigate the effect of several operating conditions on the HPT blades of a model gas turbine engine using a creep factor (CF) approach. The results show that different operating conditions can significantly affect the oxidation rates of TBCs which in turn affect the creep life of HPT blades. For instance, TBC oxidation can speed up the overall life usage of a gas turbine engine from 4.22% to 6.35% within a one-year operation. It is the objective of this research that the developed method may assist gas turbine users in selecting the best mission profile that will minimize maintenance and operating costs while giving the best engine availability.

Qualification of a Small Gas Turbine Engine as a Starter Unit

2017 ◽  
Vol 0 (0) ◽  
Author(s):  
R. K. Mishra ◽  
Prashant Kumar ◽  
K. S. Jayasihma ◽  
S. N. Mistry
Keyword(s):  
High Altitude ◽  
Gas Turbine ◽  
Sea Level ◽  
Rotational Speed ◽  
Gas Turbine Engine ◽  
Point Of View ◽  
High Rotational Speed ◽  
Turbine Engine ◽  
Starter Unit

AbstractThe certification philosophy plays an important role in ensuring the airworthiness qualification of a small gas turbine engine designed as a starter unit. The small and compactness of the engine, high rotational speed of the rotors, requirements of torque and starting capability at sea level to high altitude airfields and consecutive starts within stipulated time impose a great challenge from airworthiness point of view. This paper presents the methodology adopted and various stages of qualification, standards followed and results based on which the starter unit has been qualified for fitment on the designated aircraft.

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