scholarly journals Distinctive Features of Altitude-velocity Characteristics of Detonation Gas Turbine Engines

2018 ◽  
Vol 220 ◽  
pp. 03008
Author(s):  
Andrey Tkachenko ◽  
Viktor Rybakov ◽  
Evgeny Filinov

The paper describes the distinctive features of the altitude-velocity characteristics of detonation gas turbine engines. The necessity of developing a new type of gas turbine engines is substantiated and the main features of detonation engines are described. The principal constructive scheme of detonation gas turbine engines is presented. Developed the one-dimensional mathematical model of detonation gas turbine engine. This model describes a working process in a gas generator and a traction module. Its verification with a real prototype is performed. A number of studies were carried out using the developed mathematical model. A comparison of the pulsating engine with the classic afterburner was performed. From the obtained results it is concluded that detonation engines are more economical than the engines of traditional schemes. It was also revealed that it is possible to obtain a range of flight speeds depending on a certain height only by adjusting the gas generator according to different control laws. In this regard, the purpose of further work will be the development of a three-dimensional mathematical model of the detonation engine and the creation on its basis of a stand of virtual tests for further research.

Author(s):  
F. J. Suriano ◽  
R. D. Dayton ◽  
Fred G. Woessner

The Garrett Turbine Engine Company, a Division of the Garrett Corporation, authorized under Air Force Contract F33615-78-C-2044 and Navy Contract N00140-79-C-1294, has been conducting development work on the application of gas-lubricated hydrodynamic journal foil bearings to the turbine end of gas turbine engines. Program efforts are directed at providing the technology base necessary to utilize high-temperature foil bearings in future gas turbine engines. The main thrust of these programs was to incorporate the designed bearings, developed in test rigs, into test engines for evaluation of bearing and rotor system performance. The engine test programs included a full range of operational tests; engine thermal environment, endurance, start/stops, attitude, environmental temperatures and pressures, and simulated maneuver bearing loadings. An 88.9 mm (3.5-inch) diameter journal foil bearing, operating at 4063 RAD/SEC (38,800 rpm), has undergone test in a Garrett GTCP165 auxiliary power unit. A 44.4 mm (1.75-inch) diameter journal foil bearing, operating at 6545 RAD/SEC (62,500 rpm) has undergone test in the gas generator of the Garrett Model JFS190. This paper describes the engine test experience with these bearings.


2019 ◽  
Vol 18 (3) ◽  
pp. 67-80
Author(s):  
V. S. Kuz'michev ◽  
H. Omar ◽  
A. Yu. Tkachenko ◽  
A. A. Bobrik

Despite the fact that aviation gas turbine engines (GTE) have reached a high degree of sophistication, requirements for the improvement of their efficiency are constantly increasing. Reduction of specific fuel consumption and specific weight of the engine unit makes it possible to improve aircraft performance. One of the effective means of reducing specific fuel consumption and obtaining high thermal efficiency of a gas turbine engine is the use of heat recovery, so the interest in it holds throughout the period of development of gas turbine engines. However, the use of heat recovery in aircraft gas turbine engines is faced with a contradiction: on the one hand, heat recovery allows reducing specific fuel consumption, but, on the other hand, it increases the weight of the power plant due to the presence of a heat exchanger. Moreover, with the increase in the degree of regeneration, specific fuel consumption decreases, whereas the mass of the power plant increases.To obtain the desired effect, it is necessary to optimize simultaneously both the parameters of the engine work process and the degree of regeneration of the heat exchanger according to the criteria of evaluating the engine unit in the aircraft system. For this purpose, it is necessary to have a mathematical model for estimating the weight of a highly efficient aircraft heat exchanger. The article presents a developed mathematical model for calculating the weight of a compact plate heat exchanger used to increase the efficiency of a gas turbine engine due to the heating of compressed air entering the combustion chamber by the hot gas that enters the combustion chamber from behind the turbine. We chose a rational pattern of relative motion of the working media in the heat exchanger, the optimal type of plate-type heat transfer surface in terms of minimizing the weight of the heat exchanger and the hydraulic losses in the air and gas ducts. For the selected surface type, the dependence of the specific weight of the heat exchanger on the degree of regeneration is determined for different nozzle exhaust velocities on the basis of a computational algorithm. To assess the reliability of the obtained model, comparative analysis of the effect of the degree of regeneration on the specific weight of the heat exchanger was carried out, based on the comparison of the results of calculations for the developed model with the data of other authors and with the data for the produced regenerators.


2019 ◽  
Vol 22 (6) ◽  
pp. 8-16
Author(s):  
Sh. Ardeshiri

The current development trend of global civil aviation is the growth of passenger and freight traffic, which entails the consumption of jet fuel. Under these conditions, increasing the efficiency of jet fuel used is of great importance. Global energy consumption is constantly growing, and, first of all, the question of diversification of oil resources arises, resources from which the bulk of motor fuels is produced. Other types of raw energy sources (natural gas, coal, bio-mass) currently account for only a small part. However, an analysis of the development of jet fuels indicates that work is underway to obtain these from other sources of raw materials, especially bio-fuels. Much attention is given to obtaining bio-fuels from renewable sources – such as algae. The issue of the mass transition of civil aviation to alternative fuels is complex and requires the solution of intricate technical as well as economic issues. One of these is the assessment of the impact of new fuels on GTE performance. It is important to give an objective and quick assessment of the use of various types of fuels on the main characteristics of the engine – i.e., throttle and high-speed characteristics. In this case, it is necessary to take into account chemical processes in the chemical composition of new types of fuel. To assess the effect of fuels on the characteristics of a gas turbine engine, it is proposed to use a mathematical model that would take into account the main characteristics of the fuel itself. Therefore, the work proposes a mathematical model for calculating the characteristics of a gas turbine engine taking into account changes in the properties of the fuel itself. A comparison is made of the percentage of a mixture of biofuels and JetA1 kerosene, as well as pure JetA1 and TC-1 kerosene. The calculations, according to the proposed model, are consistent with the obtained characteristics of a gas turbine engine in operation when using JetA1 and TC-1 kerosene. Especially valuable are the obtained characteristics of a gas turbine engine depending on a mixture of biofuel and kerosene. It was found that a mixture of biofuel and kerosene changes the physicochemical characteristics of fuel and affects the change in engine thrust and specific fuel consumption. It is shown that depending on the obtained physicochemical properties of a mixture of biofuel and kerosene, it is possible to increase the fuel efficiency and environmental friendliness of the gas turbine engines used.


Author(s):  
Philippe Mathieu ◽  
Pericles Pilidis

In this paper, the use of various gaseous fuels in aero-derivative gas turbine engines is analysed. The gases investigated are natural gas and three coal synthetic gases of calorific values which are significantly lower than that of natural gas. The analysis is carried out employing natural gas fuel as a yardstick for comparison. Due to the lower calorific values of synthetic gases, the mass flow balance between compressors and turbines is altered. This in turn affects the matching of the components and the overall performance of a gas turbine engine. The engines examined are a single spool gas generator with a free power turbine and the double engine described in a previous paper. The main conclusion drawn from this analysis is that, for a given power output, the use of synthetic gases will result in an erosion of surge margins and in a reduction of the overall efficiency of the power plant.


Author(s):  
S. Morhun

The method of the gas turbine engine impeller forced vibration and stress-strain state parameters calculation is given. Using the finite element method, a refined mathematical model was developed for the several types of impellers most widespread in the practice of gas turbine engines building. The developed mathematical model takes into consideration the impeller blades geometric parameters and the construction of blades connectors. The results of its forced vibration frequencies calculation, caused by the influence of non-stationary gas flow are given for different types of the blades connectors. The dependencies of the impeller blades stress-strain state from the value its feather geometric perameters have been studied too.  


2021 ◽  
Vol 4 (8(112)) ◽  
pp. 59-66
Author(s):  
Ludmila Boyko ◽  
Vadym Datsenko ◽  
Aleksandr Dyomin ◽  
Nataliya Pizhankova

The design and adjustment of modern gas turbine engines significantly rely on the use of numerical research methods. This paper reports a method devised for calculating the thermogasdynamic parameters and characteristics of a turboshaft gas turbine engine. The special feature of a given method is a two-dimensional blade-by-blade description of the compressor in the engine system. Underlying the calculation method is a nonlinear mathematical model that makes it possible to describe the established processes occurring in individual nodes and in the engine in general. To build a mathematical model, a modular principle was chosen, involving the construction of a system of interrelated and coordinated models of nodes and their elements. The approach used in modeling a two-dimensional flow in the compressor makes it possible to estimate by calculation a significant number of parameters that characterize its operation. With the help of the reported method, it is possible to estimate the effect of changing the geometric parameters of the compressor height on the characteristics of the engine. To take into consideration the influence of variable modes of air intake or overflow in various cross-sections along the compressor tract, to determine the effect of the input radial unevenness on the parameters of the compressor and engine in general. To verify the method described, the calculation of thermogasdynamic parameters and throttle characteristics of a single-stage turboshaft gas turbine engine with a 12-stage axial compressor was performed. Comparison of the calculation results with experimental data showed satisfactory convergence. Thus, the standard deviation of the calculation results from the experimental data is 0.45 % for the compressor characteristics, 0.4 % for power, and 0.15 % for specific fuel consumption. Development and improvement of methods for calculating the parameters and characteristics of gas turbine engines make it possible to improve the quality of design and competitiveness of locally-made aircraft engines.


Author(s):  
P. A. Phillips ◽  
Peter Spear

After briefly summarizing worldwide automotive gas turbine activity, the paper analyses the power plant requirements of a wide range of vehicle applications in order to formulate the design criteria for acceptable vehicle gas turbines. Ample data are available on the thermodynamic merits of various gas turbine cycles; however, the low cost of its piston engine competitor tends to eliminate all but the simplest cycles from vehicle gas turbine considerations. In order to improve the part load fuel economy, some complexity is inevitable, but this is limited to the addition of a glass ceramic regenerator in the 150 b.h.p. engine which is described in some detail. The alternative further complications necessary to achieve satisfactory vehicle response at various power/weight ratios are examined. Further improvement in engine performance will come by increasing the maximum cycle temperature. This can be achieved at lower cost by the extension of the use of ceramics. The paper is intended to stimulate the design application of the gas turbine engine.


NDT World ◽  
2021 ◽  
pp. 58-61
Author(s):  
Aleksey Popov ◽  
Aleksandr Romanov

A large number of aviation events are associated with the surge of gas turbine engines. The article analyzes the existing systems for diagnostics of the surge of gas turbine engines. An analysis of the acoustic signal of a properly operating gas turbine engine was carried out, at which a close theoretical distribution of random values was determined, which corresponds to the studied distribution of the amplitudes of the acoustic signal. An invariant has been developed that makes it possible to evaluate the development of rotating stall when analyzing the acoustic signal of gas turbine engines. A method is proposed for diagnosing the pre-surge state of gas turbine engines, which is based on processing an acoustic signal using invariant dependencies for random processes. A hardware-software complex has been developed using the developed acoustic method for diagnosing the pre-surge state of gas turbine engines.


2021 ◽  
Author(s):  
Jeffrey S. Patterson ◽  
Kevin Fauvell ◽  
Dennis Russom ◽  
Willie A. Durosseau ◽  
Phyllis Petronello ◽  
...  

Abstract The United States Navy (USN) 501-K Series Radiological Controls (RADCON) Program was launched in late 2011, in response to the extensive damage caused by participation in Operation Tomodachi. The purpose of this operation was to provide humanitarian relief aid to Japan following a 9.0 magnitude earthquake that struck 231 miles northeast of Tokyo, on the afternoon of March 11, 2011. The earthquake caused a tsunami with 30 foot waves that damaged several nuclear reactors in the area. It was the fourth largest earthquake on record (since 1900) and the largest to hit Japan. On March 12, 2011, the United States Government launched Operation Tomodachi. In all, a total of 24,000 troops, 189 aircraft, 24 naval ships, supported this relief effort, at a cost in excess of $90.0 million. The U.S. Navy provided material support, personnel movement, search and rescue missions and damage surveys. During the operation, 11 gas turbine powered U.S. warships operated within the radioactive plume. As a result, numerous gas turbine engines ingested radiological contaminants and needed to be decontaminated, cleaned, repaired and returned to the Fleet. During the past eight years, the USN has been very proactive and vigilant with their RADCON efforts, and as of the end of calendar year 2019, have successfully completed the 501-K Series portion of the RADCON program. This paper will update an earlier ASME paper that was written on this subject (GT2015-42057) and will summarize the U.S. Navy’s 501-K Series RADCON effort. Included in this discussion will be a summary of the background of Operation Tomodachi, including a discussion of the affected hulls and related gas turbine equipment. In addition, a discussion of the radiological contamination caused by the disaster will be covered and the resultant effect to and the response by the Marine Gas Turbine Program. Furthermore, the authors will discuss what the USN did to remediate the RADCON situation, what means were employed to select a vendor and to set up a RADCON cleaning facility in the United States. And finally, the authors will discuss the dispensation of the 501-K Series RADCON assets that were not returned to service, which include the 501-K17 gas turbine engine, as well as the 250-KS4 gas turbine engine starter. The paper will conclude with a discussion of the results and lessons learned of the program and discuss how the USN was able to process all of their 501-K34 RADCON affected gas turbine engines and return them back to the Fleet in a timely manner.


Author(s):  
Matthew Driscoll ◽  
Thomas Habib ◽  
William Arseneau

The United States Navy uses the General Electric LM2500 gas turbine engine for main propulsion on its newest surface combatants including the OLIVER HAZARD PERRY (FFG 7) class frigates, SPRUANCE (DD 963) class destroyers, TICONDEROGA (CG 47) class cruisers, ARLIEGH BURKE (DDG 51) class destroyers and SUPPLY (AOE 6) class oilers. Currently, the Navy operates a fleet of over 400 LM2500 gas turbine engines. This paper discusses the ongoing efforts to characterize the availability of the engines aboard ship and pinpoint systems/components that have significant impact on engine reliability. In addition, the program plan to upgrade the LM2500’s standard configuration to improve reliability is delineated.


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