Probabilistic Design of Radial Pins Constraint System in a Gas Turbine Annular Combustion Chamber

2018 ◽  
Author(s):  
Federico Funghi ◽  
Paolo di Sisto
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Reaction Force ◽  
Probabilistic Approach ◽  
Radial Deformation ◽  
Probabilistic Design ◽  
Turbine Casing ◽  
Contact Distribution ◽  
The One ◽  
Pin Configuration

One of the possible constraint configuration of an annular combustion chamber in a gas turbine is by means of radial pins. Radial pins usually connect the outer turbine casing to the combustor dome and fix combustor axial and circumferential displacements while allowing combustor free radial deformation, under thermal loads. In the typical mounting scheme, radial pins are screwed on the outer casing and then inserted into dedicated housing holes on the dome. Because of this arrangement the force (introduced by mechanical, thermal and dynamic loads) reacted by each pin is inherently not deterministic since it depends on the actual gap between the pin itself and the housing bush on the dome, which, in turn, is not explicitly known, being a function of the overall tolerance stack up. The scope of this study was to develop a method to design the radial pins of NovaLT™16 (*) combustion chamber, applicable since the conceptual phase, using a probabilistic approach [7]. Actual pin-bush gap distribution is calculated from stack up analysis and then used as input for a numerical simulation which computes the distribution of the reaction force on each pin, as a function of number of pins, stiffness of the pin, gap between pin and bush. Two different arrangements have been considered: the classic scheme and the floating pin configuration. The new probabilistic design approach allowed to have a robust understanding of the force distribution within the whole set of pins, to compute the optimal combination of pin number, pin stiffness, and gap and ultimately to select the floating pin configuration as the one to be implemented in NovaLT16 combustor. Test results revealed pin contact distribution was in line with predictions.

Data-Driven Probabilistic Thermal Stress Analysis of a Gas Turbine Casing

2018 ◽  
Author(s):  
Zixi Han ◽  
Mian Li ◽  
Zixian Jiang ◽  
Zuoxing Min ◽  
Sophie Bourmich
Keyword(s):  
Monte Carlo ◽  
Thermal Stress ◽  
Boundary Conditions ◽  
Gas Turbine ◽  
Probabilistic Approach ◽  
Computational Time ◽  
Strength Assessment ◽  
Fixed Design ◽  
Design Values ◽  
Turbine Casing

Strength requirement is one of the most important criteria in the design of gas turbine casing. Traditionally, deterministic analyses are used in strength assessment, with boundary conditions and loads set as fixed design values. However, real boundary conditions and loads in the operation can often differ from the fixed design values, such that the mechanical integrity of the turbine casing can vary from the strength and fatigue calculations. In this work, the effect of the variability of the boundary conditions and loads is investigated on the static thermal stress problem of gas turbine casings using a probabilistic approach. The probability distribution is estimated using a Monte Carlo simulation based on the distribution of boundary conditions and loads obtained from field measurements. The finite element analysis is used to calculate the stress corresponding to different boundary conditions and a surrogate model is built to reduce the computational time of Monte Carlo simulations. This methodology is applied to a real engineering case which better quantifies the strength assessment result.

Siemens SGT-800 Industrial Gas Turbine Enhanced to 50MW: Combustor Design Modifications, Validation and Operation Experience

2013 ◽  
Author(s):  
Daniel Lörstad ◽  
Annika Lindholm ◽  
Jan Pettersson ◽  
Mats Björkman ◽  
Ingvar Hultmark
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Cooling System ◽  
Good Condition ◽  
Combined Cycle ◽  
Combustion Stability ◽  
Combustion System ◽  
Design Work ◽  
Engine Operation ◽  
Cooling Air

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.

BASIC POSITIONS OF THE ENTHALPY-ENTROPY METHODOLOGY OF THERMODYNAMIC ANALYSIS OF GAS TURBINE POWER PLANTS

2017 ◽  
Author(s):  
Gennadii Liubchik ◽  
◽  
Nataliia Fialko ◽  
Aboubakr Regragui ◽  
Nataliia Meranova ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Thermodynamic Parameters ◽  
Thermodynamic Analysis ◽  
Thermodynamic Modeling ◽  
Power Plants ◽  
Regression Equations ◽  
Thermal Entropy ◽  
Nodal Points ◽  
Computational Diagnostics

The basic positions of the enthalpy-entropy methodology of thermodynamic modeling of processes in gas turbine units (GTUs) and combined power plants on basis GTUs are presented. The main requirements and conditions of this methodology are formulated, they allows the construction of a sequential (without iterations) algorithm for the computational diagnostics of the thermodynamic parameters of the GTU cycle, which includes the calculation blocks for the compressor, combustion chamber, turbine, and exhaust tube of the GTU. The obtained regression equations are presented. The use of these equations simplifies of the procedure for evaluating the thermodynamic parameters of the components at the nodal points of the cycle. The advantages of the proposed methodology in comparison with the traditional thermal-entropy methodology are indicated.

Effect of Divergence Angle on Flow Through Inlet Section of Diffuser of a Gas Turbine Combustion Chamber: The CFD Approach

2006 ◽  
Author(s):  
Digvijay B. Kulshreshtha ◽  
S. A. Channiwala ◽  
Jitendra Chaudhary ◽  
Zoeb Lakdawala ◽  
Hitesh Solanki ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Total Pressure ◽  
Divergence Angle ◽  
Velocity Head ◽  
Turbine Engine ◽  
Inlet Velocity ◽  
Pressure Losses ◽  
Flow Through ◽  
Mach Numbers

In the combustor inlet diffuser section of gas turbine engine, high-velocity air from compressor flows into the diffuser, where a considerable portion of the inlet velocity head PT3 − PS3 is converted to static pressure (PS) before the airflow enters the combustor. Modern high through-flow turbine engine compressors are highly loaded and usually have high inlet Mach numbers. With high compressor exit Mach numbers, the velocity head at the compressor exit station may be as high as 10% of the total pressure. The function of the diffuser is to recover a large proportion of this energy. Otherwise, the resulting higher total pressure loss would result in a significantly higher level of engine specific fuel consumption. The diffuser performance must also be sensitive to inlet velocity profiles and geometrical variations of the combustor relative to the location of the pre-diffuser exit flow path. Low diffuser pressure losses with high Mach numbers are more rapidly achieved with increasing length. However, diffuser length must be short to minimize engine length and weight. A good diffuser design should have a well considered balance between the confliction requirements for low pressure losses and short engine lengths. The present paper describes the effect of divergence angle on diffuser performance for gas turbine combustion chamber using Computational Fluid Dynamic Approach. The flow through the diffuser is numerically solved for divergence angles ranging from 5 to 25°. The flow separation and formation of wake regions are studied.

Chemical Kinetic Analysis of a Flameless Gas Turbine Combustor

2008 ◽  
Author(s):  
G. Arvind Rao ◽  
Yeshayahou Levy ◽  
Ephraim J. Gutmark
Keyword(s):  
Combustion Chamber ◽  
Kinetic Analysis ◽  
Gas Turbine ◽  
Flame Temperature ◽  
Plug Flow ◽  
Combustion Process ◽  
Chemical Reactor ◽  
Chemical Kinetic ◽  
Combustion Regime ◽  
Reactor Model

Flameless combustion (FC) is one of the most promising techniques of reducing harmful emissions from combustion systems. FC is a combustion phenomenon that takes place at low O2 concentration and high inlet reactant temperature. This unique combination results in a distributed combustion regime with a lower adiabatic flame temperature. The paper focuses on investigating the chemical kinetics of an prototype combustion chamber built at the university of Cincinnati with an aim of establishing flameless regime and demonstrating the applicability of FC to gas turbine engines. A Chemical reactor model (CRM) has been built for emulating the reactions within the combustor. The entire combustion chamber has been divided into appropriate number of Perfectly Stirred Reactors (PSRs) and Plug Flow Reactors (PFRs). The interconnections between these reactors and the residence times of these reactors are based on the PIV studies of the combustor flow field. The CRM model has then been used to predict the combustor emission profile for various equivalence ratios. The results obtained from CRM model show that the emission from the combustor are quite less at low equivalence ratios and have been found to be in reasonable agreement with experimental observations. The chemical kinetic analysis gives an insight on the role of vitiated combustion gases in suppressing the formation of pollutants within the combustion process.

Modeling of pollutant emission from the combustion chamber of a stationary gas turbine drive

2014 ◽  
Vol 57 (3) ◽  
pp. 283-290
Author(s):  
I. A. Zaev ◽  
B. V. Potapkin ◽  
S. A. Fedorov ◽  
V. V. Kuprik
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Pollutant Emission ◽  
Turbine Drive

Towards the Multiobjective Optimisation of Gas Turbine Combustors

2006 ◽  
Author(s):  
S. G. Wyse ◽  
G. T. Parks ◽  
R. S. Cant
Keyword(s):  
Transfer Function ◽  
Tabu Search ◽  
Combustion Chamber ◽  
Gas Turbine ◽  
Design Space ◽  
Objective Functions ◽  
Multiobjective Optimisation ◽  
Gas Turbine Combustor ◽  
Linear Network ◽  
Good Design

Gas turbine combustor design entails multiple, and often contradictory, requirements for the designer to consider. Multiobjective optimisation on a low-fidelity linear-network-based code is suggested as a way of investigating the design space. The ability of the Tabu Search optimiser to minimise NOx and CO, as well as several acoustic objective functions, is investigated, and the resulting “good” design vectors presented. An analysis of the importance of the flame transfer function in the model is also given. The mass flow and the combustion chamber width and area are shown to be very important. The length of the plenum and the widths of the plenum exit and combustor exit also influence the design space.

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