scholarly journals Pulsating Combustion Applied to a Small Gas Turbine

Author(s):  
J. A. C. Kentfield ◽  
P. Yerneni

A description is given of, what is believed to be the first test ever made of a gas turbine in which a valveless pulsed combustor replaced the conventional steady flow combustor. It is explained that the main incentive for using a pulsed combustor in a gas turbine is to achieve a net stagnation pressure gain between the compressor outlet and the turbine inlet. Brief descriptions are given of the pulsed combustor and the adaptation of the small gas turbine, which was of the gas generator type, to receive the pulsating combustion system. Results are presented which show that the gas turbine operated successfully using the pulsed combustor and that a very small net stagnation-pressure gain was achieved. An indication is given of possible future developments which should result in improved performance.

Author(s):  
Carroll D. Porter

A valveless combustor has been developed which has been tested at one to three atmospheres of pressure. It discharged combustion products at practical turbine-inlet temperatures and at a total pressure above that of the inlet. Developmental problems encountered and results are discussed. The smooth combustor cycle, a phased system of combustor tubes and pulsation traps, achieves steady flow at the inlet and outlet of the combustor system to preserve the high efficiency of today’s turbines and compressors. The combustor will soon be tested on a gas-turbine compressor to verify efficiency gain estimates.


Author(s):  
Sepehr Sanaye ◽  
Salahadin Hosseini

A novel procedure for finding the optimum values of design parameters of industrial twin-shaft gas turbines at various ambient temperatures is presented here. This paper focuses on being off design due to various ambient temperatures. The gas turbine modeling is performed by applying compressor and turbine characteristic maps and using thermodynamic matching method. The gas turbine power output is selected as an objective function in optimization procedure with genetic algorithm. Design parameters are compressor inlet guide vane angle, turbine exit temperature, and power turbine inlet nozzle guide vane angle. The novel constrains in optimization are compressor surge margin and turbine blade life cycle. A trained neural network is used for life cycle estimation of high pressure (gas generator) turbine blades. Results for optimum values for nozzle guide vane/inlet guide vane (23°/27°–27°/6°) in ambient temperature range of 25–45 ℃ provided higher net power output (3–4.3%) and more secured compressor surge margin in comparison with that for gas turbines control by turbine exit temperature. Gas turbines thermal efficiency also increased from 0.09 to 0.34% (while the gas generator turbine first rotor blade creep life cycle was kept almost constant about 40,000 h). Meanwhile, the averaged values for turbine exit temperature/turbine inlet temperature changed from 831.2/1475 to 823/1471°K, respectively, which shows about 1% decrease in turbine exit temperature and 0.3% decrease in turbine inlet temperature.


Author(s):  
M. K. Pulimood

This paper outlines the field experience gained from the modular retrofitting of four gas turbine inlet systems with a second stage high efficiency media filter to reduce gas turbine fouling conditions. The original gas turbine inlet systems were furnished with inertial filters. Within a few thousand hours of operation considerable gas turbine performance loss had occurred. Field inspection revealed excessive fouling of the gas generator axial compressor sections, and crusty dust particle build up within the gas turbine internals and thermocouples. A second-stage high efficiency media filter was retrofitted, to capture the fine dust particles that passed through the inertial filters. Follow-up inspection of the two-stage filter systems, after about 8000 hr of operation, disclosed little indication of the engine fouling conditions that were present prior to the retrofitting.


Author(s):  
W. R. Lynn

The unique control problems associated with vehicular gas turbine engines are forcing the requirement for more direct measurement and control of vehicular gas turbine operating parameters. Two of the most important parameters are gas generator turbine inlet temperature and engine flameout. The major problem controlling these parameters has always been the lack of low cost sensors with sufficient accuracy and response for closed loop control along with the life required for economical operation. Two sensors have been developed which have the necessary response and accuracy for application to vehicular gas turbine controls. These sensors are also rugged and reliable and will provide the required long life. A fluidic temperature sensor measures turbine inlet temperature and an ultraviolet radiation sensor detects the presence of flame. Both sensors have electronic outputs and are readily adaptable to present electronic control systems. The principle of operation, accuracy and response data, along with application and installation information is presented for both sensors.


Author(s):  
J. A. C. Kentfield ◽  
L. C. V. Fernandes

Further development work is described, which included both theoretical analysis and experimental testing, of an improved prototype, valveless, pulse, pressure gain, combustor for gas turbines. The analytical work involved the application to the non-steady flow in the combustor secondary flow duct of the method-of-characteristics as used for one-space dimensional, time dependent, compressible flows. Gas temperatures in the secondary flow duct were measured experimentally as were the pressure gain, due to the pulse combustor, and the overall efficiencies of the gas generator type gas-turbine with both the conventional steady flow combustor and the alternative pulse, pressure gain, combustor. It was concluded that the analytical work confirmed earlier experimental findings showing the benefits of restricting the secondary flow duct exit area. It was also concluded that the use of the pulse combustor resulted in a maximum improvement of 27% in the thermal efficiency of the small, low pressure-ratio, educational, gas generator turbo-machine.


Author(s):  
Stephen Gallimore ◽  
R. Michael Vickers ◽  
Michael B. Boyns

The Tornado gas turbine was designed at a time when emissions legislation was minimal and was developed through the eighties to accept water or steam injection for NOX reduction. In recent years it has become necessary to develop dry methods of emissions reduction for new engine sales and to enable existing operators to retrofit their engines when legislation demands. The compact design of the Tornado’s centre section did not lend itself to a simple combustor changeout. The lean pre-mix dry low emissions (DLE) system developed for the Typhoon gas turbine required additional combustor length for CO burnout and could not be fitted into the existing casings of the Tornado engine. The challenge was therefore to redesign the centre section to enable the DLE system to be fitted without compromising the design of the compressor, HP turbine and gas generator rotor. This paper describes the methodology used and the design of the engine centre section together with the results of design and performance validation undertaken including emissions measurements.


Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 389
Author(s):  
Jinfu Liu ◽  
Zhenhua Long ◽  
Mingliang Bai ◽  
Linhai Zhu ◽  
Daren Yu

As one of the core components of gas turbines, the combustion system operates in a high-temperature and high-pressure adverse environment, which makes it extremely prone to faults and catastrophic accidents. Therefore, it is necessary to monitor the combustion system to detect in a timely way whether its performance has deteriorated, to improve the safety and economy of gas turbine operation. However, the combustor outlet temperature is so high that conventional sensors cannot work in such a harsh environment for a long time. In practical application, temperature thermocouples distributed at the turbine outlet are used to monitor the exhaust gas temperature (EGT) to indirectly monitor the performance of the combustion system, but, the EGT is not only affected by faults but also influenced by many interference factors, such as ambient conditions, operating conditions, rotation and mixing of uneven hot gas, performance degradation of compressor, etc., which will reduce the sensitivity and reliability of fault detection. For this reason, many scholars have devoted themselves to the research of combustion system fault detection and proposed many excellent methods. However, few studies have compared these methods. This paper will introduce the main methods of combustion system fault detection and select current mainstream methods for analysis. And a circumferential temperature distribution model of gas turbine is established to simulate the EGT profile when a fault is coupled with interference factors, then use the simulation data to compare the detection results of selected methods. Besides, the comparison results are verified by the actual operation data of a gas turbine. Finally, through comparative research and mechanism analysis, the study points out a more suitable method for gas turbine combustion system fault detection and proposes possible development directions.


2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 347-348
Author(s):  
Kelsey Schubach ◽  
Bruno I Cappellozza ◽  
Marcos Renato Burim ◽  
André Velasco ◽  
Fernando Sagrado ◽  
...  

Abstract Alternatives that alleviate stress-related responses and improve performance of the beef cattle herd are imperative and deserve further investigation. In previous trials, administration of the bovine appeasing substance (BAS) has improved performance of newly-weaned and feedlot received beef animals, as well as reduced the risk of dark, firm, and dry (DFD) cuts in carcass obtained from Bos indicus cattle. Therefore, this study was designed to evaluate the effects of BAS administration at castration on pre-conditioning performance of crossbred beef animals. On day 0, 390 crossbred Angus × Nellore animals were ranked by initial shrunk BW (255 ± 21.1 kg) and assigned to receive or not (CON) 5 mL/head of BAS (SecureCattle; Nutricorp, Araras, SP, Brazil) immediately before castration. From d 0 to 30, animals within treatments were maintained in 2 feedot pens with a minimum distance (300 m) to avoid contact between treatment groups and received a grass hay-based diet (70:30 roughage:concentrate ratio) ad libitum. On day 30, animals were individually weighed following 16 hours of feed and water restriction. Hence, a descriptive analysis was performed to evaluate pen dry matter intake (DMI) and feed efficiency (FE). Animal was considered the experimental unit and all data were analyzed using the PROC MIXED procedure of SAS (version 9.4; SAS Inst. Inc., Cary, NC). Bovine appeasing substance administration at castration improved ADG and BW change (P < 0.0001) compared with CON cohorts (0.983 vs. 1.155 kg/d and 29.5 vs. 34.6 kg for ADG and BW change, respectively). Total DMI was similar among treatments when reported as kg/d (6.70 vs. 6.75 kg) or % of BW (2.48 vs. 2.48%), whereas FE was dramatically improved in BAS-administered animals (146 vs. 172 g/kg for CON and BAS, respectively). In summary, BAS administration improved performance of crossbred beef animals for 30 days post-castration.


Author(s):  
Daniel Lörstad ◽  
Annika Lindholm ◽  
Jan Pettersson ◽  
Mats Björkman ◽  
Ingvar Hultmark

Siemens Oil & Gas introduced an enhanced SGT-800 gas turbine during 2010. The new power rating is 50.5MW at a 38.3% electrical efficiency in simple cycle (ISO) and best in class combined-cycle performance of more than 55%, for improved fuel flexibility at low emissions. The updated components in the gas turbine are interchangeable from the existing 47MW rating. The increased power and improved efficiency are mainly obtained by improved compressor airfoil profiles and improved turbine aerodynamics and cooling air layout. The current paper is focused on the design modifications of the combustor parts and the combustion validation and operation experience. The serial cooling system of the annular combustion chamber is improved using aerodynamically shaped liner cooling air inlet and reduced liner rib height to minimize the pressure drop and optimize the cooling layout to improve the life due to engine operation hours. The cold parts of the combustion chamber were redesigned using cast cooling struts where the variable thickness was optimized to maximize the cycle life. Due to fewer thicker vanes of the turbine stage #1, the combustor-turbine interface is accordingly updated to maintain the life requirements due to the upstream effect of the stronger pressure gradient. Minor burner tuning is used which in combination with the previously introduced combustor passive damping results in low emissions for >50% load, which is insensitive to ambient conditions. The combustion system has shown excellent combustion stability properties, such as to rapid load changes and large flame temperature range at high loads, which leads to the possibility of single digit Dry Low Emission (DLE) NOx. The combustion system has also shown insensitivity to fuels of large content of hydrogen, different hydrocarbons, inerts and CO. Also DLE liquid operation shows low emissions for 50–100% load. The first SGT-800 with 50.5MW rating was successfully tested during the Spring 2010 and the expected performance figures were confirmed. The fleet leader has, up to January 2013, accumulated >16000 Equivalent Operation Hours (EOH) and a planned follow up inspection made after 10000 EOH by boroscope of the hot section showed that the combustor was in good condition. This paper presents some details of the design work carried out during the development of the combustor design enhancement and the combustion operation experience from the first units.


Sign in / Sign up

Export Citation Format

Share Document