Semi-Closed Gas Turbine Cycles: An Ecological Solution

Author(s):  
A. L. Laganelli ◽  
C. Rodgers ◽  
W. E. Lear ◽  
P. L. Meitner

The impact on global warming of transportation and the infrastructure that supports it has been investigated over several decades. Anthropogenic heat and the generation of greenhouse gases from burning of fossil fuels and are major contributors to the warming process. An approach to mitigate these effects is discussed that considers semi-closed cycle gas turbine engines as a practical approach to slowing the release of greenhouse gases. Semi-closed cycle gas turbine engines have an inherent capability to reduce all regulated emissions while maintaining high efficiency, which in turn reduces CO2 emissions. With emerging technology development that includes higher component efficiencies, high temperature material development, improved control devices, and advanced combustor designs, aided by computational fluid dynamics, semi-closed cycle engines appear to have the potential to mitigate global warming with little economic or infrastructural impact. A specific semi-closed engine type is described, the high pressure recuperated turbine engine (HPRTE), along with the inherent mechanisms for control of NOx, CO, unburned hydrocarbons, and particulates. Results from a breadboard demonstration of the HPRTE are discussed, as well as emerging technologies which benefit this type of engine.

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 2107 ◽  
Author(s):  
Sergey Borovik ◽  
Yuriy Sekisov

The creation and exploitation of gas turbine engines (GTE) often involve two mutually exclusive tasks related to ensuring the highest reliability while achieving a good economic and environmental performance of the power plant. The value of the radial clearance between the blade tips of the compressor or turbine and the stator is a parameter that has a significant impact on the efficiency and safety of the GTE. However, the radial displacements that form tip clearances are only one of the components of the displacements made by GTE elements due to the action of power loads and thermal deformations during engines’ operation. The impact of loads in conjunction with natural aging is also the reason for the wear of the GTE’s structural elements (for example, bearing assemblies) and the loss of their mechanical strength. The article provides an overview of the methods and tools for monitoring the dangerous states of the GTE (blade tips clearances, impellers and shafts displacements, debris detecting in lubrication system) based on the single-coil eddy current sensor, which remains operational at the temperatures above 1200 °C. The examples of practical application of the systems with such sensors in bench tests of the GTE are given.


Author(s):  
J. A. Saintsbury ◽  
P. Sampath

The impact of potential aviation gas turbine fuels available in the near to midterm, is reviewed with particular reference to the small aviation gas turbine engine. The future course of gas turbine combustion R&D, and the probable need for compromise in fuels and engine technology, is also discussed. Operating experience to date on Pratt & Whitney Aircraft of Canada PT6 engines, with fuels not currently considered of aviation quality, is reported.


1985 ◽  
Vol 107 (1) ◽  
pp. 205-211 ◽  
Author(s):  
J. H. Griffin ◽  
A. Sinha

This paper summarizes the results of an investigation to establish the impact of mistuning on the performance and design of blade-to-blade friction dampers of the type used to control the resonant response of turbine blades in gas turbine engines. In addition, it discusses the importance of friction slip force variations on the dynamic response of shrouded fan blades.


1980 ◽  
Author(s):  
A. D. Harper

The ability of small utilities to meet future customer requirements for fairly priced and reliable electric power will depend on their capability either to purchase inexpensive electric power from larger utilities or to produce power from their own high-efficiency generating systems. In the not too distant future, small utilities will also be faced with the reality of burning coal. In order to help meet these future needs, The Garrett Corporation, in conjunction with the Electric Power Research Institute (EPRI), conducted a conceptual design study to evaluate the suitability of high-efficiency gas turbine engines for external firing with a multifuel (including coal) combustion heat source. A primary goal was to synthesize a system that could be placed on the market by 1985 with normal (but not accelerated) R&D funding.


Author(s):  
Paolo Chiesa ◽  
Stefano Consonni ◽  
Giovanni Lozza ◽  
Ennio Macchi

It is well known that the history of gas turbine engines has been characterized by a very clear trend toward higher and higher operating temperatures, a growth which in the past 40 years has progressed at the impressive pace of approximately 13°C/year. Expected improvements in blade cooling techniques and advancements in materials indicate that this tendency is going to last for long time, leading to firing temperatures of over 1500°C within the next two decades. This paper investigates the impact of such temperature increase on optimal cycle arrangements and on ultimate performance improvements achievable by future advanced gas/steam cycles for large-scale power generation. Performance predictions have been carried out by a modified, improved version of a computer code originally devised and calibrated for “1990 state-of-the-art” gas/steam cycles. The range of performances to be expected in the next decades has been delimited by considering various scenarios of cooling technology and materials, including the extreme situations of adiabatic expansion and stoichiometric combustion. The results of parametric thermodynamic analyses of several cycle configurations are presented for a number of technological scenarios, including cycles with intercooling and reheat. A specific section discusses how the optimum configuration of the bottoming steam cycle changes to keep up with exhaust gas temperature increases. Calculations show that, under plausible assumptions on future technology advancements, within two decades the proper selection of plant configuration and operating parameters can yield net efficiencies of over 60%.


1976 ◽  
Vol 13 (03) ◽  
pp. 309-314
Author(s):  
F. Critelli ◽  
A. Pietsch ◽  
N. Spicer

The Maritime Administration, in its pursuit of improved economics and advanced technology, initiated a study which would evaluate new marine powerplants. It became quite apparent for several sound technical reasons that the closed-cycle gas turbine engine afforded an excellent opportunity for achievement of Mar-Ad's goal. This paper addresses the new-technology engine as applied to maritime ships, illustrating the advantages to shipowners and operators. Efficiency, multifuel capability, installation flexibility, reduction in ship's manning, as well as the overall reduced operating cost are highlighted in this paper.


2021 ◽  
Vol 2 ◽  
pp. 21-25
Author(s):  
Vladimir Baranovsky ◽  
Maxim Lipatov

A wide range of efficient gas turbine engines has been developed at UEC NPO Saturn, Russia. Those engines can be successfully used for developing a marine steam-gas semi-closed cycle power plant to compensate peak loads on ships and vessels. This compact steam-gas power plant will demonstrate high efficiency which doesn’t change significantly depending on the load when compared to conventional steam-gas power plants. Also, this solution can possibly change the diesel engine prevalence among marine power plants.


2021 ◽  
Author(s):  
Ashwini Karmarker ◽  
Jacqueline O’Connor ◽  
Isaac Boxx

Abstract Combustion instability, which is the result of a coupling between combustor acoustic modes and unsteady flame heat release rate, is a severely limiting factor in the operability and performance of modern gas turbine engines. This coupling can occur through different coupling pathways, such as flow field fluctuations or equivalence ratio fluctuations. In realistic combustor systems, there are complex hydrodynamic and thermo-chemical processes involved, which can lead to multiple coupling pathways. In order to understand and predict the mechanisms that govern the onset of combustion instability in real gas turbine engines, we consider the influences that each of these coupling pathways can have on the stability and dynamics of a partially-premixed, swirl-stabilized flame. In this study, we use a model gas turbine combustor with two concentric swirling nozzles of air, separated by a ring of fuel injectors, operating at an elevated pressure of 5 bar. The flow split between the two streams is systematically varied to observe the impact on the flow and flame dynamics. High-speed stereoscopic particle image velocimetry, OH planar laser-induced fluorescence, and acetone planar laser-induced fluorescence are used to obtain information about the velocity field, flame, and fuel-flow behavior, respectively. Depending on the flow conditions, a thermoacoustic oscillation mode or a hydrodynamic mode, identified as the precessing vortex core, is present. The focus of this study is to characterize the mixture coupling processes in this partially-premixed flame as well as the impact that the velocity oscillations have on mixture coupling. Our results show that, for this combustor system, changing the flow split between the two concentric nozzles can alter the dominant harmonic oscillation modes in the system, which can significantly impact the dispersion of fuel into air, thereby modulating the local equivalence ratio of the flame. This insight can be used to design instability control mechanisms in real gas turbine engines.


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