Teaching Gas Turbine Technology to Undergraduate Students in Sweden

Author(s):  
Ioanna Aslanidou ◽  
Valentina Zaccaria ◽  
Evangelia Pontika ◽  
Nathan Zimmerman ◽  
Anestis I. Kalfas ◽  
...  

This paper addresses the teaching of gas turbine technology in a third-year undergraduate course in Sweden and the challenges encountered. The improvements noted in the reaction of the students and the achievement of the learning outcomes is discussed. The course, aimed at students with a broad academic education on energy, is focused on gas turbines, covering topics from cycle studies and performance calculations to detailed design of turbomachinery components. It also includes economic aspects during the operation of heat and power generation systems and addresses combined cycles as well as hybrid energy systems with fuel cells. The course structure comprises lectures from academics and industrial experts, study visits, and a comprehensive assignment. With the inclusion of all of these aspects in the course, the students find it rewarding despite the significant challenges encountered. An important contribution to the education of the students is giving them the chance, stimulation, and support to complete an assignment on gas turbine design. Particular attention is given on striking a balance between helping them find the solution to the design problem and encouraging them to think on their own. Feedback received from the students highlighted some of the challenges and has given directions for improvements in the structure of the course, particularly with regards to the course assignment. This year, an application developed for a mobile phone in the Aristotle University of Thessaloniki for the calculation of engine performance will be introduced in the course. The app will have a supporting role during discussions and presentations in the classroom and help the students better understand gas turbine operation. This is also expected to reduce the workload of the students for the assignment and spike their interest.

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.


2020 ◽  
Vol 11 (1) ◽  
pp. 28
Author(s):  
Emmanuel O. Osigwe ◽  
Arnold Gad-Briggs ◽  
Theoklis Nikolaidis

When selecting a design for an unmanned aerial vehicle, the choice of the propulsion system is vital in terms of mission requirements, sustainability, usability, noise, controllability, reliability and technology readiness level (TRL). This study analyses the various propulsion systems used in unmanned aerial vehicles (UAVs), paying particular focus on the closed-cycle propulsion systems. The study also investigates the feasibility of using helium closed-cycle gas turbines for UAV propulsion, highlighting the merits and demerits of helium closed-cycle gas turbines. Some of the advantages mentioned include high payload, low noise and high altitude mission ability; while the major drawbacks include a heat sink, nuclear hazard radiation and the shield weight. A preliminary assessment of the cycle showed that a pressure ratio of 4, turbine entry temperature (TET) of 800 °C and mass flow of 50 kg/s could be used to achieve a lightweight helium closed-cycle gas turbine design for UAV mission considering component design constraints.


Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3521 ◽  
Author(s):  
Panagiotis Stathopoulos

Conventional gas turbines are approaching their efficiency limits and performance gains are becoming increasingly difficult to achieve. Pressure Gain Combustion (PGC) has emerged as a very promising technology in this respect, due to the higher thermal efficiency of the respective ideal gas turbine thermodynamic cycles. Up to date, only very simplified models of open cycle gas turbines with pressure gain combustion have been considered. However, the integration of a fundamentally different combustion technology will be inherently connected with additional losses. Entropy generation in the combustion process, combustor inlet pressure loss (a central issue for pressure gain combustors), and the impact of PGC on the secondary air system (especially blade cooling) are all very important parameters that have been neglected. The current work uses the Humphrey cycle in an attempt to address all these issues in order to provide gas turbine component designers with benchmark efficiency values for individual components of gas turbines with PGC. The analysis concludes with some recommendations for the best strategy to integrate turbine expanders with PGC combustors. This is done from a purely thermodynamic point of view, again with the goal to deliver design benchmark values for a more realistic interpretation of the cycle.


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):  
Z. Stanley Stys

Application of the gas turbine in nitric-acid plants appears attractive. Several of these units have been installed recently in this country and performance and operating experience already have been gained. Design, construction, and layout of “package” units for this particular process are described.


Author(s):  
Chippa Anil ◽  
Aparna Satheesh ◽  
Babu Santhanagopalakrishnan ◽  
Marcin Bielecki

Abstract Heavy duty gas turbines are usually equipped with hydrodynamic bearings which are either lemon-bore or tilting pad type. Baker Hughes legacy gas turbines use these two types of bearings, and its selection is based on 1) considering pros & cons from Rotor dynamics, 2) bearing performance, 3) bearing housing stiffness, 4) vibration detection & control. Non-contact probes are used to monitor the vibrations of rotor. Majority of legacy gas turbines are not equipped with these probes. Due to this fact, over the years it resulted in non-detection of dynamics & vibration issue, which caused frequent bearing replacement. As the increase in industry demand to apply and measure vibrations using non-contact probes on bearings, an effort was made by Baker Hughes to implement these on existing fleet units. Also, in order to increase rotor dynamics stability of low-pressure rotor, to improve bearing life and performance, effort was made to replace lemon-bore bearings with tilting pad. This paper demonstrates efforts made to design the titling pad which would fit within envelop of already available bearing housing. Bearing/shaft clearance, bearing performance, modification of bearing retainer clearances are the mandatory tasks which would be dealt in this study. The swap of bearing type, and its effect on whole gas turbine rotor dynamic stability, checking the frequency crossovers with Campbell diagram would also be dealt in this paper. This paper also focuses on assessment on oil passage routing, temperature & proximity probe instrumentation routing design. Re-design is performed by analyzing various configuration, assessing different sensitivity studies & validation of modified bearing housing from structural integrity, ultimate load capability, & split plane oil leakage retention and its comparison with baseline are most important aspects of finalization of this change, which will be showcased in this paper. Instrumentation routing was a critical task when the considering bearing replacement from lemon-bore to tilting pad. As lemon-bore type bearings just have an elliptical inner surface, it’s quite easy to install the thermocouples into a simple hole. But as replacement has tilting pads, the challenge is to instrument the pads without effecting their movement and functionality. Such best practices are also dealt in this paper. Comparison of tilting-pad with lemon-bore, considering the fixed shaft diameter, the retainer outer diameter of tilting pad is higher than lemon-bore. This effect has a change in bearing seat on bearing housing, thereby reducing the effective stiffness of the housing, and the reduced split plane surface. To tackle this situation, several sensitivities were executed, by re-modifying the bolts and bolt holes on the existing housing, without modifying the housing envelop.


Author(s):  
R. Friso ◽  
N. Casari ◽  
M. Pinelli ◽  
A. Suman ◽  
F. Montomoli

Abstract Gas turbines (GT) are often forced to operate in harsh environmental conditions. Therefore, the presence of particles in their flow-path is expected. With this regard, deposition is a problem that severely affects gas turbine operation. Components’ lifetime and performance can dramatically vary as a consequence of this phenomenon. Unfortunately, the operating conditions of the machine can vary in a wide range, and they cannot be treated as deterministic. Their stochastic variations greatly affect the forecasting of life and performance of the components. In this work, the main parameters considered affected by the uncertainty are the circumferential hot core location and the turbulence level at the inlet of the domain. A stochastic analysis is used to predict the degradation of a high-pressure-turbine (HPT) nozzle due to particulate ingestion. The GT’s component analyzed as a reference is the HPT nozzle of the Energy-Efficient Engine (E3). The uncertainty quantification technique used is the probabilistic collocation method (PCM). This work shows the impact of the operating conditions uncertainties on the performance and lifetime reduction due to deposition. Sobol indices are used to identify the most important parameter and its contribution to life. The present analysis enables to build confidence intervals on the deposit profile and on the residual creep-life of the vane.


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.


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