The Development of a Model for the Assessment of Bio-Fouling in Gas Turbine System

Author(s):  
Tosin Onabanjo ◽  
Giuseppina Di Lorenzo ◽  
Eric Goodger ◽  
Pericles Pilidis

A significant problem encountered in the gas turbine industry with fuel products is the degradation of fuel and fuel systems by microorganisms, which are largely bacteria, embedded in biofilms. These microorganisms cause system fouling and other degradatory effects, extending often to sudden failure of components with cost implications. Current methods of assessment are only post-impact evaluation and do not necessarily quantify the effects of fuel degradation on engine performance and emission. Therefore, effective models that allow predictive condition monitoring are required for engine’s fuel system reliability, especially with readily biodegradable biofuels. The aim of this paper is to introduce the concept of bio-fouling in gas turbines and the development of a bio-mathematical model with potentials to predict the extent and assess the effects of microbial growth in fuel systems. The tool takes into account mass balance stoichiometry equations of major biological processes in fuel bio-fouling. Further development, optimization and integration with existing Cranfield in-house simulation tools will be carried out to assess the overall engine performance and emission characteristics. This new tool is important for engineering design decision, optimization processes and analysis of microbial fuel degradation in gas turbine fuels and fuel systems.

Author(s):  
Tosin Onabanjo ◽  
Giuseppina Di Lorenzo ◽  
Eric Goodger ◽  
Pericles Pilidis

A significant problem encountered in the gas turbine industry with fuel products is the degradation of fuel and fuel systems by micro-organisms, which are largely bacteria, embedded in biofilms. These micro-organisms cause system fouling and other degradatory effects, extending often to sudden failure of components with cost implications. Current methods of assessment are only postimpact evaluation and do not necessarily quantify the effects of fuel degradation on engine performance and emission. Therefore, effective models that allow predictive condition monitoring are required for engine's fuel system reliability, especially with readily biodegradable biofuels. The aim of this paper is to introduce the concept of biofouling in gas turbines and the development of a biomathematical model with potentials to predict the extent and assess the effects of microbial growth in fuel systems. The tool takes into account mass balance stoichiometry equations of major biological processes in fuel biofouling. Further development, optimization, and integration with existing Cranfield in-house simulation tools will be carried out to assess the overall engine performance and emission characteristics. This new tool is important for engineering design decision, optimization processes, and analysis of microbial fuel degradation in gas turbine fuels and fuel systems.


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.


Author(s):  
C. Rodgers

By the new millennia gas turbine technology standards the size of the first gas turbines of Von Ohain and Whittle would be considered small. Since those first pioneer achievements the sizes of gas turbines have diverged to unbelievable extremes. Large aircraft turbofans delivering the equivalent of 150 megawatts, and research micro engines designed for 20 watts. Microturbine generator sets rated from 2 to 200kW are penetrating the market to satisfy a rapid expansion use of electronic equipment. Tiny turbojets the size of a coca cola can are being flown in model aircraft applications. Shirt button sized gas turbines are now being researched intended to develop output powers below 0.5kW at rotational speeds in excess of 200 Krpm, where it is discussed that parasitic frictional drag and component heat transfer effects can significantly impact cycle performance. The demarcation zone between small and large gas turbines arbitrarily chosen in this treatise is rotational speeds of the order 100 Krpm, and above. This resurgence of impetus in the small gas turbine, beyond that witnessed some forty years ago for potential automobile applications, fostered this timely review of the small gas turbine, and a re-address of the question, what are the effects of size and clearances gaps on the performances of small gas turbines?. The possible resolution of this question lies in autopsy of the many small gas turbine component design constraints, aided by lessons learned in small engine performance development, which are the major topics of this paper.


Author(s):  
Uyioghosa Igie ◽  
Marco Abbondanza ◽  
Artur Szymański ◽  
Theoklis Nikolaidis

Industrial gas turbines are now required to operate more flexibly as a result of incentives and priorities given to renewable forms of energy. This study considers the extraction of compressed air from the gas turbine; it is implemented to store heat energy at periods of a surplus power supply and the reinjection at peak demand. Using an in-house engine performance simulation code, extractions and injections are investigated for a range of flows and for varied rear stage bleeding locations. Inter-stage bleeding is seen to unload the stage of extraction towards choke, while loading the subsequent stages, pushing them towards stall. Extracting after the last stage is shown to be appropriate for a wider range of flows: up to 15% of the compressor inlet flow. Injecting in this location at high flows pushes the closest stage towards stall. The same effect is observed in all the stages but to a lesser magnitude. Up to 17.5% injection seems allowable before compressor stalls; however, a more conservative estimate is expected with higher fidelity models. The study also shows an increase in performance with a rise in flow injection. Varying the design stage pressure ratio distribution brought about an improvement in the stall margin utilized, only for high extraction.


2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Stian Madsen ◽  
Lars E. Bakken

Optimized operation of gas turbines is discussed for a fleet of 11 GE LM2500PE engines at a Statoil North Sea offshore field in Norway. Three engines are generator drivers, and eight engines are compressor drivers. Several of the compressor drive engines are running at peak load (T5.4 control), hence, the production rate is limited by the available power from these engines. The majority of the engines discussed run continuously without redundancy, hence, the gas turbine uptime is critical for the field's production and economy. The performance and operational experience with online water wash at high water-to-air ratio (w.a.r.), as well as successful operation at longer maintenance intervals and higher average engine performance are described. The water-to-air ratio is significantly increased compared to the original equipment manufacturer (OEM) limit (OEM limit is 17 l/min which yields approximately 0.5% water-to-air ratio). Today the engines are operated at a water rate of 50 l/min (three times the OEM limit) which yields a 1.4% water-to-air ratio. Such a high water-to-air ratio has been proven to be the key parameter for obtaining good online water wash effectiveness. Possible downsides of high water-to-air ratio have been thoroughly studied.


Author(s):  
Panteleimon Kazatzis ◽  
Riti Singh ◽  
Pericles Pilidis ◽  
Jean-Jacques Locquet

The power-speed requirements of warships and the poor part load efficiency of simple cycle gas turbines has given rise to the design of many ship installations where two types of gas turbines are used. A large type for high speed, at full power, and a small one for cruise. It is common to mount two units of each type. This design results in a large amount of bulky and heavy ducting, much more voluminous and heavy than the gas turbines themselves. The present paper outlines an investigation into a novel intercooled split-cycle with some deck mounted components. This reduces the requirement for internal ducts in the ships hull, essentially, to those needed by the cruise engine. The engine performance has been predicted and a comparison is carried out between a traditional installation and the one investigated. An estimate has been carried out of the flow conditions of the duct to assess the change in losses for operation in the cruise and the full power condition. The new scheme appears to be promising.


Author(s):  
Kenneth W. Van Treuren

The gas turbine industry is experiencing growth in many sectors. An important part of teaching a gas turbine course is exposing students to the practical applications of the gas turbine. This laboratory proposes an opportunity for students to view an operating gas turbine engine in an aircraft propulsion application and to model the engine performance. A Pratt and Whitney PT6A-20 turboprop was run at a local airfield and engine parameters typical of cockpit instrumentation were taken. The students, in teams of two, then modeled the system using the software PARA and PERF in an attempt to match the manufacturer’s specifications. This laboratory required students to research the parameters necessary to model this engine that were not part of the data set provided by the manufacturer. The research and modeling encompassed areas such as technology level, efficiencies, fuel consumption, and performance. The end result was a two-page report containing the students’ calculations comparing the actual performance of the engine with the manufacturer’s specifications. Supporting graphs and figures were included as appendices. The same type laboratory could be adapted for co-generation gas turbines. Over 121 colleges and universities have co-generation facilities on campus and that presents a unique opportunity for the students to observe the operation of a land-based gas turbine used for power generation. A 5 MW TB5000 manufactured by Ruston (Alstom) Gas Engines is available on the Baylor University campus and is highlighted as an example. Potential problems encountered with using the Baylor University gas turbine are discussed which include lack of appropriate engine instrumentation.


2014 ◽  
Vol 136 (10) ◽  
Author(s):  
Uyioghosa Igie ◽  
Pericles Pilidis ◽  
Dimitrios Fouflias ◽  
Kenneth Ramsden ◽  
Panagiotis Laskaridis

Industrial gas turbines are susceptible to compressor fouling, which is the deposition and accretion of airborne particles or contaminants on the compressor blades. This paper demonstrates the blade aerodynamic effects of fouling through experimental compressor cascade tests and the accompanied engine performance degradation using turbomatch, an in-house gas turbine performance software. Similarly, on-line compressor washing is implemented taking into account typical operating conditions comparable with industry high pressure washing. The fouling study shows the changes in the individual stage maps of the compressor in this condition, the impact of degradation during part-load, influence of control variables, and the identification of key parameters to ascertain fouling levels. Applying demineralized water for 10 min, with a liquid-to-air ratio of 0.2%, the aerodynamic performance of the blade is shown to improve, however most of the cleaning effect occurred in the first 5 min. The most effectively washed part of the blade was the pressure side, in which most of the particles deposited during the accelerated fouling. The simulation of fouled and washed engine conditions indicates 30% recovery of the lost power due to washing.


Author(s):  
M. A. Monroe ◽  
A. H. Epstein ◽  
H. Kumakura ◽  
K. Isomura

The performance of a regenerated gas turbine generator in the 3–5 kW power range has been analyzed to understand why its measured efficiency was on the order of 6% rather than the 20% suggested by consideration of its components’ efficiencies as measured on rigs. This research suggests that this discrepancy can be primarily attributed to heat and fluid leaks not normally considered in the analysis of large gas turbine engines because they are not as important at large scale. In particular, fluid leaks among the components and heat leakage from the hot section into the compressor flow path contributed the largest debits to the engine performance. Such factors can become more important as the engine size is reduced. Other non-ideal effects reducing engine performance include temperature flow distortion at the entrance to both the compressor and turbine. A cycle calculation including all of the above effects matched measured engine data. It suggests that relatively simple changes such as thermal isolation and leak sealing can increase both power output and efficiency of this engine, over 225% in the latter case. The validity of this analysis was demonstrated on an engine in which partial thermal isolation and improved sealing resulted in a more than 40% increase in engine output power.


1992 ◽  
Vol 114 (2) ◽  
pp. 161-168 ◽  
Author(s):  
I. S. Diakunchak

This paper describes the most important factors affecting the industrial gas turbine engine performance deterioration with service time and provides some approximate data on the prediction of the rate of deterioration. Recommendations are made on how to detect and monitor the performance deterioration. Preventative measures, which can be taken to avoid or retard the performance deterioration, are described in some detail.


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