Development and Testing of a 10 kW Diffusive Micromix Combustor for Hydrogen-Fuelled µ-Scale Gas Turbines

Author(s):  
H. H.-W. Funke ◽  
A. E. Robinson ◽  
U. Ro¨nna

There is a growing need for devices with small weight and large power density as a substitute for today’s accumulators widely used for electrical tools or as thrust application in the aerospace industry e.g. for small unmanned aerial vehicles (UAV). Systems burning liquid or gaseous fuels and working after the principle of the Brayton cycle became more and more interesting as a new field of research (powermems devices). This ongoing miniaturization of power devices such as ultra micro gas turbines requires a reliable and safe combustion of fuels. A new test rig for micro scale combustion chambers has been realized and tested with a new hydrogen prototype burner for a 600 W μ-scale gas turbine. By preheating and pressurizing the flow realistic combustion chamber inlet conditions for the design point and for μ-scale gas turbine part load conditions can be realized. Furthermore the quartz glass prototype burner offers visual access to the flame region during operation at atmospheric condition. Detailed investigations on the burning characteristics for different chamber configurations were carried out for an optimization of the burner concept and gas turbine integration. By changing air mass flow and thermal energy the results allow a mapping of the combustion chamber for setting the control laws of the μ-scale gas turbine. The test results prove a very good flame stability and burning efficiency for the micromix principle covering a wide range of power settings including the design point. Even at extreme part load conditions it was possible to handle all the operating points of the proposed μ-scale gas turbine. Based on the prototype burner results a realistic combustion chamber design for μ-scale gas turbine integration will be presented.

Author(s):  
M. S. N. Murthy ◽  
Subhash Kumar ◽  
Sheshadri Sreedhara

Abstract A gas turbine engine (GT) is very complex to design and manufacture considering the power density it offers. Development of a GT is also iterative, expensive and involves a long lead time. The components of a GT, viz compressor, combustor and turbine are strongly dependent on each other for the overall performance characteristics of the GT. The range of compressor operation is dependent on the functional and safe limits of surging and choking. The turbine operating speeds are required to be matched with that of compressor for wide range of operating conditions. Due to this constrain, design for optimum possible performance is often sacrificed. Further, once catered for a design point, gas turbines offer low part load efficiencies at conditions away from design point. As a more efficient option, a GT is practically achievable in a split configuration, where the compressor and turbine rotate on different shafts independently. The compressor is driven by a variable speed electric motor. The power developed in the combustor using the compressed air from the compressor and fuel, drives the turbine. The turbine provides mechanical shaft power through a gear box if required. A drive taken from the shaft rotates an electricity generator, which provides power for the compressor’s variable speed electric motor through a power bank. Despite introducing, two additional power conversions compared to a conventional GT, this split configuration named as ‘Part Electric Gas Turbine’, has a potential for new applications and to achieve overall better efficiencies from a GT considering the poor part load characteristics of a conventional GT.


Author(s):  
Marek Dzida ◽  
Krzysztof Kosowski

In bibliography we can find many methods of determining pressure drop in the combustion chambers of gas turbines, but there is only very few data of experimental results. This article presents the experimental investigations of pressure drop in the combustion chamber over a wide range of part-load performances (from minimal power up to take-off power). Our research was carried out on an aircraft gas turbine of small output. The experimental results have proved that relative pressure drop changes with respect to fuel flow over the whole range of operating conditions. The results were then compared with theoretical methods.


2018 ◽  
Vol 140 (03) ◽  
pp. S54-S55
Author(s):  
Uwe Schütz

This article describes features and advantages of new mobile gas turbine with a wide range of applications. The market for mobile gas turbines is continuously growing. Mobile units are also an ideal choice when it comes to making large power capacities available on a short-term basis, for example, for major events, prolonged downtimes at other power stations, or power-intensive applications such as mining or shale gas extraction. If the electricity requirements exceed the level that can normally be demanded of a mobile application, an SGT-A45 installation can be modified to form a combined-cycle power plant to further improve its efficiency. In remote locations, this can be achieved using an Organic Rankine Cycle (ORC), to eliminate the need for water and water treatment systems, and to optimize energy recovery from the SGT-A45 off-gas stream at a relatively low temperature. The use of a direct heat exchanger, in which the ORC working fluid is evaporated by the off-gas stream from the gas turbine, can boost the system’s output capacity by more than 20 percent.


Author(s):  
T S Kim ◽  
S T Ro

This paper demonstrates a favourable influence of turbine coolant modulation on the part load performance of gas turbines. A general simulation programme is developed, which is capable of accurately estimating the design and part load performance of modern heavy-duty gas turbines characterized by intensive turbine blade cooling Investigations are made for a typical gas turbine and two distinct load control schemes are considered: the fuel-only control and the variable compressor geometry control. Maintaining blade temperatures as high as possible whose purpose is to minimize coolant consumption is simulated. It is found that the coolant modulation makes the part load characteristics deviate from usual behaviours and creates a considerable enhancement of part load thermal efficiency. For the fuel-only control with coolant modulation, it is predicted that efficiency can be higher than design efficiency over a wide range of part load operation.


Author(s):  
S. Vesely´ ◽  
S. Pary´zek ◽  
E. Vinogradov ◽  
Y. Zakharov ◽  
A. Soudarev

The environmentally friendly modification of gas turbine combustion chambers is a process for altering the structure of combustion, mainly in the primary zone in order to reduce the emission of NOx, CO, and solids into the atmosphere. The ecological modernization of gas turbines that are currently in operation is a continually topical subject because there are several thousand turbine units in Europe that do not meet current emission limits. At the same time, it can be expected that the emission limits for these turbines operating in the European Union will be reduced to NOx≤75 mg/m3, CO≤100 mg/m3 in working range of 40–100% of the gas turbine output after the year 2010. The authors have developed a new construction of a hybrid low-emission natural gas burner. Developmental work was performed both on one burner and also in a burner group consisting of seven hybrid burners. Results will be presented in this paper for model conditions for the atmospheric test rig and their re-calculation to the operational parameters on the real gas turbine. A conception with variable primary section combustion chamber geometry has been used to achieve low emissions in a wide range of gas turbine output allowing the organization of the combustion process with a constant gas/air mixing ratio coefficient. A prototype of a combustion chamber with a hybrid burner group with control of the primary air mass flow has been manufactured and tested in a 6 MW gas turbine operating in a gas pipeline compressor plant. The achieved emission characteristics will be presented and compared with precalculations. The experiments made on the real gas turbine have proven the possibility of meeting the target emission limit performance of NOx≤50 mg/m3, CO≤50 mg/m3. Other possibilities how to reduce harmful emissions for this burner type will be presented in this paper.


Author(s):  
E. Tsoutsanis ◽  
Y. G. Li ◽  
P. Pilidis ◽  
M. Newby

Part-load performance prediction of gas turbines is strongly dependent on detailed understanding of engine component behavior and mainly that of compressors. The accuracy of gas turbine engine models relies on the compressor performance maps, which are obtained in costly rig tests and remain manufacturer’s proprietary information. The gas turbine research community has addressed this limitation by scaling default generic compressor maps in order to match the targeted off-design measurements. This approach is efficient in small range of operating conditions but becomes less accurate for wide range of operating conditions. In this part of the paper a novel method of compressor map generation which has a primary objective to improve the accuracy of engine models performance at part load conditions is presented. This is to generate a generic form of equations to represent the lines of constant speed and constant efficiency of the compressor map for a generic compressor. The parameters that control the shape of the compressor map have been expressed in their simplest form in order to aid the adaptation process. The proposed compressor map generation method has the capacity to refine current gas turbine performance adaptation techniques, and it has been integrated into Cranfield’s PYTHIA gas turbine performance simulation and diagnostics software tool.


2021 ◽  
Author(s):  
Jamie Lim ◽  
Christopher A. Perullo ◽  
Joe Milton ◽  
Rachel Whitacre ◽  
Chris Jackson ◽  
...  

Abstract EPRI has been developing a digital twin of simple and combined cycle gas turbines over the last 5+ years to provide owners and operators with improved capabilities that typically reside in the expert domain of OEMs and 3rd party service providers. The digital twin is a digital model, a physics-based representation of the actual asset. The model is thermodynamic and is created with the intent to support 5 M&D areas: • Integrate with existing M&D tools such as advanced pattern recognition (APR) • Power plant performance prediction and trending such as day, week, and month ahead performance prediction for capacity and generation planning • Health Monitoring and Fault Diagnostics to support asset management with additional health scores and virtual instrumentation enabled by the digital twin model • Monitoring and prediction of both base and part-load performance. Many gas turbine tools have been simplified to work only at full load conditions. To be useful and to improve utilization of collected data, part-load conditions should also be considered. • Outage and repair impacts, including “what-if” capability to understand and quantify potential root causes of less than expected performance improvement or recovery after outage and repairs. This paper presents current progress in creating an EPRI Digital Twin applicable to gas turbines. The formulation, methodology, and real-world use cases are presented. To date, digital twins have been created and tested for both E and F class frames. This paper describes the process of generating closed-form equations capable of transforming existing, measured historian data into the health parameters and virtual sensors needed to better track unit health and monitor faulted performance. These equations encapsulate the digital twin physical model and provide end-users with a methodology to calibrate to their specific unit and efficiently use their choice of monitoring software. Tests have been performed using operator data and have shown good accuracy at detecting anomalous operation and predicting week ahead performance with excellent accuracy. Post-outage impact analysis is also assessed. Real-world application cases for the digital twin are also presented. Examples include using the digital twin to identify causes of post-outage emissions and performance issues, expected impact of degradation and fault conditions, and simulating improvements to operation through part repair and upgrades.


Author(s):  
C. Kalathakis ◽  
N. Aretakis ◽  
I. Roumeliotis ◽  
A. Alexiou ◽  
K. Mathioudakis

Solar hybrid gas turbine performance is studied through consideration of four engine configurations: a) single shaft, b) recuperated single-shaft, c) twin-shaft and d) two-spool three-shaft, intercooled, recuperated. For each configuration and for the same design point, the performance is obtained for two hybridization schemes: Fuel only engines Retrofitted for Solar operation (FRS) and engines designed with Solar only operation at the Design Point (SDP). In an attempt to further improve the benefits of hybridization, the concept of a Dual Fluid Receiver for exploiting the rejected solar power, during sunny hours with high irradiation, is demonstrated. Steam is produced by focusing the defocused mirrors of the heliostat field to a second receiver and injected into the combustion chamber. For the cases examined, it can be concluded that FRS engines show better performance than SDP ones, since they exhibit higher thermal fuel efficiency and higher specific power. Concerning the configurations, an annual fuel saving of ∼35% and an annual output reduction, ranging from 4% for the recuperated single-shaft configuration to 9% for the twin shaft configuration compared to the corresponding fuel-only engines is demonstrated. The inclusion of a Dual Fluid Receiver in an FRS engine removes the power penalty while it maintains the fuel saving benefit.


Author(s):  
E. Mohammadi ◽  
M. Montazeri-Gh

In this paper, common faults in main components of an industrial two-shaft gas turbine are simulated, and the fault signatures are determined in both part and full-load conditions. As fouling and erosion are the most important and effective causes of performance deterioration in gas turbines (GTs), the effects of these faults on the performance of all three main components including compressor, gas generator turbine, and power turbine are studied and their effects on the overall efficiency of the whole system are analyzed. In this study, the faults simulation is performed by changing the health parameters (flow capacity and isentropic efficiency) of each GT components via modification of the compressor and turbines characteristic curves. The results obtained from the compressor fouling simulation are validated against the published experimental data; the validation results represent acceptable simulation accuracy in estimation of the measurement parameters deviation. Moreover, the fault signatures are determined in full-load conditions, and the effects of the examined faults on the main GT parameters are analyzed; in this way, the key measurement parameters in identification of these faults are introduced. Finally, in order to identify the fault signatures in part-load conditions, the fault implantation process is performed for each 10% reduction in gas turbine loads. Simulation results demonstrate that the fault signatures have different sensitivity to load variations, and thus, these are in general a function of the GT loading conditions.


Author(s):  
Karl W. Karstensen ◽  
Jesse O. Wiggins

Gas turbines have been accepted in naval surface ship applications, and considerable effort has been made to improve their fuel consumption, particularly at part-load operation. This is an important parameter for shipboard engines because both propulsion and electrical-generator engines spend most of their lives operating at off-design power. An effective way to improve part-load efficiency of recuperated gas turbines is by using a variable power turbine nozzle. This paper discusses the successful use of variable power turbine nozzles in several applications in a family of engines developed for vehicular, industrial, and marine use. These engines incorporate a variable power turbine nozzle and primary surface recuperator to yield specific fuel consumption that rivals that of medium speed diesels. The paper concentrates on the experience with the variable nozzle, tracing its derivation from an existing fixed vane nozzle and its use across a wide range of engine sizes and applications. Emphasis is placed on its potential in marine propulsion and auxiliary gas turbines.


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