scholarly journals Analysis of unstable mode of a free gas turbine of turbo-compressors engines

2021 ◽  
Vol 345 ◽  
pp. 00009
Author(s):  
Marián Hocko ◽  
Samer Al-Rabeei
Keyword(s):  
Gas Turbine ◽  
Unstable Mode ◽  
Flight Safety ◽  
Free Gas ◽  
Mode Of Operation ◽  
Helicopter Pilots

This paper analyses unstable mode of a free gas turbine of turboshaft helicopter engine TV3-117. The analysis is focused on the conditions of this phenomenon and the possibilities of its solution in a turboshaft helicopter engine and an industrial turbocharger engine with a free gas turbine. Knowing the causes of the unstable mode of operation of a free gas turbine will allow helicopter pilots to prevent accidents and increase the level of flight safety.

Strategy for a Cost Optimized Operation of a Flexible Cogeneration Gas Turbine Plant

2000 ◽  
Author(s):  
D. Hein ◽  
K. Kwanka ◽  
M. Nixdorf
Keyword(s):  
Gas Turbine ◽  
Control Strategy ◽  
Operating Experience ◽  
Economic Potential ◽  
Cogeneration Plant ◽  
Turbine Plant ◽  
Mode Of Operation ◽  
Gas Turbine Plant ◽  
Technical Framework

A new gas turbine cogeneration plant based on the Cheng cycle was installed to supply electricity and heat for the Technische Universität München’s campus site at Garching. To utilize fully the Cheng cycle flexibility, an optimizing system was developed which controls the mode of operation continuously and adapts the point of operation without manual interface. Only with such a system it is possible to exploit the full economic potential of the system. The paper presents the technical framework and some aspects of the control strategy used to minimize the costs based on three years of operating experience.

Identification and Correction of Rotor Instability in an Oil-Free Gas Turbine

2008 ◽  
Author(s):  
Daniel R. Lubell ◽  
Jonathan L. Wade ◽  
Navjot S. Chauhan ◽  
John G. Nourse
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Early Stage ◽  
Turbine Wheel ◽  
Free Gas ◽  
Foil Bearings ◽  
Root Cause ◽  
Final Design ◽  
Acceptance Tests ◽  
Conventional Oil

The direction of advanced gas turbines and other turbomachinery has been towards oil-free designs, enabled by the significant improvements of high temperature foil bearings. The advantages of oil-free gas turbines have been studied and shown to be realistic. However, the oil-free technology is still at an early stage in its development relative to conventional oil lubricated turbomachinery systems which have been studied and manufactured for about 100 years, and the bearings even longer. Oil-free gas turbines are most successful as a system design initiated with oil-free bearings. Making these successful designs requires knowledge of the strengths and weaknesses of integrating oil-free bearings. A common example is foil bearings, the type typically considered for oil-free gas turbines. These bearings are lower in damping than their oil lubricated counterparts. Therefore special considerations are made by the experienced oil-free gas turbine designer early in the design process. Knowledge of the opportunities for instability that are not as common in conventional turbomachinery provides value to the final design. This paper presents the identification and correction of rotor instability in an oil-free microturbine of a 65 kW system. The manufacturer put significant effort into identifying the root cause of the seemingly random occurrences of rotor instability, in order to improve yield for acceptance tests. Through the application of conventional rotordynamics theory and techniques, combined with 3-D imaging of complex cast parts, the root cause was identified as an Alford’s-type force at the turbine driven by critical machined and cast features of the turbine wheel that would not have been important in a conventional oil lubricated turbomachine. A successful corrective process has been put in place, providing final confirmation of the root cause.

Understanding the Dynamics of Critical Transitions in a Contra-Rotating Fan

2021 ◽  
Author(s):  
Manas Madasseri Payyappalli ◽  
A. M. Pradeep
Keyword(s):  
Mass Flow ◽  
Unstable Mode ◽  
Low Frequencies ◽  
Flow Rates ◽  
High Frequencies ◽  
Tip Leakage ◽  
Critical Transitions ◽  
Mode Of Operation ◽  
Mass Flow Rates ◽  
Low Mass

Abstract In this experimental study, we investigate the fundamental behaviour of a low speed contra-rotating fan and describes the reasons leading to the instabilities in the fan at low mass flow rates. A contra-rotating fan is a possible alternative to conventional fans and has potential aerodynamic advantages. This study identifies certain features that are unique to a contra-rotating configuration. Rotor-1 and rotor-2 behaves differently at low mass flow rates. Though rotor-1 is stable up to low mass flow rates, rotor-2 enters into an unstable mode of operation at mass flow rates close to the design mass flow rate. The critical region where the instability arise in rotor-1 is its tip and in rotor-2 is its hub. The instability is also found to change the structure as it propagates along the annulus. It is identified that the presence of rotor-2 downstream of rotor-1 under-loads rotor-1 and thus significantly affects the loading on rotor-1. The instability arises due to the tip-leakage vortex at high frequencies and due to modal waves at low frequencies. The study thus identifies the major regions of the rotors which are the sources of instabilities and also identifies the process of transition to instability in the contra-rotating fan.

Turbine Fuel Ignition and Combustion Facility for Extremely Low Temperature Conditions

2004 ◽  
Author(s):  
G. Pucher ◽  
W. D. Allan
Keyword(s):  
Data Acquisition ◽  
Combustion Chamber ◽  
Gas Turbine ◽  
High Speed ◽  
Air Cooling ◽  
Test Rig ◽  
Ignition System ◽  
Temperature Conditions ◽  
Air Temperatures ◽  
Mode Of Operation

As the temperature of combustion air and fuels are reduced, the ability to achieve ignition within gas turbine engines becomes increasingly difficult. Several factors share responsibility, related largely to the physical characteristics of fuel emerging from nozzles, whereby an increasing fuel viscosity with temperature reduction results in larger average fuel droplets. The ensuing reduced surface area hinders fuel evaporation within an environment where evaporation is already impeded by low partial pressures due to low ambient temperature conditions and/or depending on the mode of operation, due to a high altitude environment. To study the effects of extremely low air and fuel temperatures on gas turbine fuel ignition performance, a dual mode (namely for cold start and altitude relight) test rig has been designed and commissioned. Its main components include a turbo-jet combustion chamber section, fuel system, ignition system, fuel/air cooling systems, and data acquisition/instrumentation. For airflow within the combustion chamber, two alternate sources are used, depending on the mode of operation. As such, this rig allows key parameters related to gas turbine ignition, such as fuel flow, fuel viscosity, ignition characteristics, airflow, and pressure conditions to be monitored and recorded. Highlights of this test rig include a General Electric J-85 combustion chamber section with quartz windows, fuel and air cooling via cryogenic liquids (LN2 for the fuel, LN2 and LOx for air), fuel and air closed loop temperature control, high speed data acquisition, a gas turbine exciter or, as selected, a custom programmable ignition system. Airflow is provided either by twin 11 HP blowers providing up to 0.5 kg/s of airflow to simulate sea level start conditions, or through the entrainment of high velocity air to simulate relight conditions at up to 21000 feet altitude. This rig is capable of achieving minimum inlet air temperatures and fuel temperatures lower than −45°C. A series of commissioning tests was undertaken with the rig in both ground start and altitude (low pressure) configurations. In order to study viscosity effects on ignition performance, two common gas turbine fuels were utilized, namely JP-4 (F-40) and JP-8 (F-34). Ignition fuel flows as well as lean blowout flows for a stock injector design are presented for these fuels across a matrix of fuel and air temperatures. Conclusions are drawn and future developments are described.

Plate Fin Regenerators for Industrial Gas Turbines

1978 ◽  
Vol 100 (4) ◽  
pp. 576-585 ◽  
Author(s):  
K. W. Cuffe ◽  
P. K. Beatenbough ◽  
M. J. Daskavitz ◽  
R. J. Flower
Keyword(s):  
High Temperature ◽  
Gas Turbine ◽  
Gas Turbines ◽  
The Past ◽  
Mode Of Operation ◽  
Industrial Gas Turbines ◽  
Industrial Gas Turbine ◽  
High Temperature Operation ◽  
Surface Changes

This paper reviews Harrison Radiator’s various designs and improvements in the Industrial Gas Turbine Regenerator that it has been supplying over the past 20 years, and describes a new design regenerator intended for high cyclic and/or high temperature operation. Design improvements and surface changes have occurred to keep pace with the changing consumer’s requirements and application. These changes have been effective in improving the cyclic ability of the regenerator and in reducing the field maintenance required on the earlier models due to the changing mode of operation. The new regenerator design has been created to meet the changing requirements of the applications.

High efficiency gas-turbine power generator GTU-2U

2020 ◽  
Vol 2 (4) ◽  
pp. 185-195
Author(s):  
M. Yu. Egorushkov ◽  
V. Yu. Ivanov ◽  
A. A. Murugov ◽  
A. V. Sheverdin
Keyword(s):  
Power Generation ◽  
Natural Gas ◽  
Gas Turbine ◽  
Power Supply ◽  
Energy Generation ◽  
Gas Production ◽  
Liquefied Natural Gas ◽  
Small Scale ◽  
Mode Of Operation ◽  
Small Capacity

Introduction: the analysis of the main areas of energy transition (energie wende) from fossil fuels and nuclear power generation to renewable sources of energy has identified the following four key problems: electric power shortage; ageing of power generation facilities; insufficient infrastructure; growing demand for gas fuel. In Russia, distributed small-scale power generation facilities serve those consumers who have no access to centralized power supply or network channels of regular power generation. A combination of versatile approaches to electric power generation should be applied in the course of designing a specific energy generation facility in this context.Methods: the research project represents an analysis of the works written by the leading Russian and foreign researchers specializing on power engineering, namely, energy supply to consumers. The expert assessment method has identified the niches which are best fitted by gas turbine facilities. Computerized and simulation modeling techniques were used to perform the analytical and statistical processing of the project findings.Results and discussion: the trend for the structural improvement of small-scale liquefied natural gas facilities has been identified in the course of the research. The author has substantiated development of systems for power supply to smallcapacity liquefied natural gas production facilities. The proposed gas turbine GTU-2U is designated for generation of electric energy, if in operation as a standalone facility as part of a centralized heating and power plant in the standalone mode of operation, or in case of concurrent operation along with an energy generation system within the framework of distributed small capacity networks. The co-authors have substantiated the unit’s practical application and identified the GTU-2U distribution market both in Russia and abroad: small capacity distributed power generation industry and power supply to small-capacity liquefied natural gas production facilities. The latter is a relatively new market which is in the process of proactive development both in mature and developing economies. This power supply pattern will enable to monetize gas deposits, located far from pipelines and to supply gas to hard-to-access regions.Conclusion: the key trends in the development of the contemporary power generation industry are considered in the article. Gas turbine unit GTU-2U has been designed. This unit is capable of generating power both as a standalone facility, as a component of a centralized heating and power plant in the standalone mode of operation, or in case of concurrent operation along with an energy generation system. Its strengths substantiate its practical application both in the Russian and international power generation markets.

scholarly journals First V84.3A Gas Turbine Installation at Hawthorn Station

1997 ◽  
Author(s):  
T. Johnson ◽  
B. Becker ◽  
J. Seume ◽  
H. Termuehlen
Keyword(s):  
Gas Turbine ◽  
Kansas City ◽  
Combined Cycle ◽  
Load Test ◽  
Test Facility ◽  
Synchronous Condenser ◽  
Mode Of Operation ◽  
Steam Cooling ◽  
Cycle Efficiency ◽  
Fuel Costs

The first V84.3A gas turbine as tested at the full-load test facility of the Siemens gas turbine factory in Berlin, Germany has now been installed at the Kansas City Power & Light (KCP&L) Company’s Hawthorn Power Station. The unit will be started in spring of this year and is scheduled to be available in June for the 1997 summer peak. In times when active power is not in demand, the generator can be operated as a synchronous condenser. For this mode of operation, a synchronous clutch has been installed between the gas turbine and the generator. The advanced V84.3A gas turbine has been chosen because of its high simple cycle efficiency based on the measured 38% in the test facility, providing peaking capacity with a minimum on fuel costs. In addition, later conversion to highly efficient combined cycle operation can easily be performed without the need for external air or even steam cooling systems.

Gas Turbine Performance of Mature, F- and Advanced Technologies 2000

2001 ◽  
Author(s):  
Axel W. von Rappard ◽  
Salvatore Della Villa
Keyword(s):  
United States ◽  
Gas Turbine ◽  
Power Plants ◽  
Power Production ◽  
The United States ◽  
Combined Cycle ◽  
Advanced Technology ◽  
United States Department ◽  
The Past ◽  
Mode Of Operation

The contribution of the gas turbine in simple and combined cycle systems to power production in the United States has been steadily rising over the past 25 years. In 1998 their contribution to power production was approximately 15% and it increased over the past 5 years by 1.5 to 2%, annually. In parallel, the United States Department of Energy (DOE) has financially supported Advanced Technology development with good formulated goals for overall performance of plants including reliability, availability and maintainability (RAM). In this paper the authors evaluate RAM performance data from power plants over the past five years. This evaluation can be used as baseline or benchmark for further improvements. It takes into account the mode of operation being base load, cycling or peaking application and analyses the power plant on a year-by-year evaluation. All RAM-data came from the same source and are collected and analyzed according to standardized procedures. Availability will be reviewed for machines of different sizes and technologies. Maintainability will be analyzed as function of the size of units, energy production, and the mode of operation. Gas turbine simple and combined cycle power plants have been operated in peaking, cycling, base and continuous load operation. The flexibility is shown in different “Service Hours per Successful Start” and a correlation with the RAM parameters. To analyze and explain these differences will be the main result of this evaluation. The contribution shall help to evaluate the best solution for individual sites because efficiency and availability cannot always be increased in parallel.

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