A New Experimental Facility to Investigate Combustor-Turbine Interactions in Gas Turbines With Multiple Can Combustors

2014 ◽  
Author(s):  
S. Luque ◽  
V. Kanjirakkad ◽  
I. Aslanidou ◽  
R. Lubbock ◽  
B. Rosic ◽  
...  
Keyword(s):  
Gas Turbines ◽  
High Speed ◽  
Cooling System ◽  
Guide Vane ◽  
Experimental Facility ◽  
Blow Down ◽  
Guide Vanes ◽  
Wide Range ◽  
Nozzle Guide ◽  
Nozzle Guide Vanes

This paper describes a new modular experimental facility that was purpose-built to investigate flow interactions between the combustor and first stage nozzle guide vanes of heavy duty power generation gas turbines with multiple can combustors. The first stage turbine nozzle guide vane is subjected to the highest thermal loads of all turbine components and therefore consumes a proportionally large amount of cooling air that contributes detrimentally to the stage and cycle efficiency. It has become necessary to devise novel cooling concepts that can substantially reduce the coolant air requirement but still allow the turbine to maintain its aerothermal performance. The present work aims to aid this objective by the design and commissioning of a high-speed linear cascade which consists of two can combustor transition ducts and four first stage nozzle guide vanes. This is a modular non-reactive air test platform with engine realistic geometries (gas path and near gas path), cooling system, and boundary conditions (inlet swirl, turbulence level and boundary layer). The paper presents the various design aspects of the high pressure blow down type facility, and the initial results from a wide range of aerodynamic and heat transfer measurements under highly engine realistic conditions.

A New Experimental Facility to Investigate Combustor–Turbine Interactions in Gas Turbines With Multiple Can Combustors

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
S. Luque ◽  
V. Kanjirakkad ◽  
I. Aslanidou ◽  
R. Lubbock ◽  
B. Rosic ◽  
...  
Keyword(s):  
Gas Turbines ◽  
High Speed ◽  
Cooling System ◽  
Experimental Facility ◽  
Blow Down ◽  
Wide Range ◽  
Flow Interactions ◽  
Inlet Swirl ◽  
Nozzle Guide ◽  
Cooling Air

This paper describes a new modular experimental facility that was purpose-built to investigate flow interactions between the combustor and first stage nozzle guide vanes (NGVs) of heavy duty power generation gas turbines with multiple can combustors. The first stage turbine NGV is subjected to the highest thermal loads of all turbine components and therefore consumes a proportionally large amount of cooling air that contributes detrimentally to the stage and cycle efficiency. It has become necessary to devise novel cooling concepts that can substantially reduce the coolant air requirement but still allow the turbine to maintain its aerothermal performance. The present work aims to aid this objective by the design and commissioning of a high-speed linear cascade, which consists of two can combustor transition ducts and four first stage NGVs. This is a modular nonreactive air test platform with engine realistic geometries (gas path and near gas path), cooling system, and boundary conditions (inlet swirl, turbulence level, and boundary layer). The paper presents the various design aspects of the high pressure (HP) blow down type facility, and the initial results from a wide range of aerodynamic and heat transfer measurements under highly engine realistic conditions.

Nozzle Guide Vane Static Strip Seals

2006 ◽  
Author(s):  
Arash Farahani ◽  
Peter Childs
Keyword(s):  
Gas Turbines ◽  
Guide Vane ◽  
Main Stream ◽  
Guide Vanes ◽  
Advantages And Disadvantages ◽  
Air System ◽  
Improved Performance ◽  
Nozzle Guide ◽  
Nozzle Guide Vanes ◽  
Assembly Constraints

Sealing of components where there is no relative motion between the elements concerned remains a significant challenge in many gas turbine engine applications. Loss of sealing and cooling air from the internal air system through seals impacts on specific fuel consumption and can lead to undesirable flow interactions with resultant cost implications. For gas turbines, various strip seal types have been developed for use between Nozzle Guide Vanes in order to limit the flow of gas between the main stream annulus and the internal air system. Many different types of design have been proposed for overcoming strip seal problems such as misalignment of the grooves due to manufacturing and assembly constraints. In this paper various methods, with a particular focus on patents, for minimising the amount of leakage caused by such problems for strip seals between nozzle guide vanes are reviewed. By considering the advantages and disadvantages of each technique it is concluded that although apparently new strip seal designs for NGVs have improved performance, none of them can be considered to be ideal. This paper reviews the techniques and makes recommendations for future designs.

scholarly journals Unsteady phenomena at the combustor-turbine interface

2021 ◽  
Vol 5 ◽  
pp. 202-215
Author(s):  
Faisal Shaikh ◽  
Budimir Rosic
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
High Speed ◽  
Guide Vane ◽  
Secondary Flows ◽  
Test Facility ◽  
Unsteady Heat Transfer ◽  
Guide Vanes ◽  
Nozzle Guide ◽  
Nozzle Guide Vanes

The combustor-turbine interface in a gas turbine is characterised by complex, highly unsteady flows. In a combined experimental and large eddy simulation (LES) study including realistic combustor geometry, the standard model of secondary flows in the nozzle guide vanes (NGV) is found to be oversimplified. A swirl core is created in the combustion chamber which convects into the first vane passages. Four main consequences of this are identified: variation in vane loading; unsteady heat transfer on vane surfaces; unsteadiness at the leading edge horseshoe vortex, and variation in the position of the passage vortex. These phenomena occur at relatively low frequencies, from 50–300 Hz. It seems likely that these unsteady phenomena result in non-optimal film cooling, and that by reducing unsteadiness designs with greater cooling efficiency could be achieved. Measurements were performed in a high speed test facility modelling a large industrial gas turbine with can combustors, including nozzle guide vanes and combustion chambers. Vane surfaces and endwalls of a nozzle guide vane were instrumented with 384 high speed thin film heat flux gauges, to measure unsteady heat transfer. The high resolution of measurements was such to allow direct visualisation in time of large scale turbulent structures over the endwalls and vane surfaces. A matching LES simulation was carried out in a domain matching experimental conditions including upstream swirl generators and transition duct. Data reduction allowed time-varying LES data to be recorded for several cycles of the unsteady phenomena observed. The combination of LES and experimental data allows physical explanation and visualisation of flow events.

Effect of the Combustor Wall on the Aerothermal Field of a Nozzle Guide Vane

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Ioanna Aslanidou ◽  
Budimir Rosic
Keyword(s):  
Gas Turbines ◽  
High Speed ◽  
Guide Vane ◽  
Leading Edge ◽  
Flow Structures ◽  
Experimental Facility ◽  
Aerodynamic Loss ◽  
Nozzle Guide Vane ◽  
Nozzle Guide ◽  
Processing Techniques

In gas turbines with can combustors, the trailing edge (TE) of the combustor transition duct wall is found upstream of every second vane. This paper presents an experimental and numerical investigation of the effect of the combustor wall TE on the aerothermal performance of the nozzle guide vane. In the measurements carried out in a high-speed experimental facility, the wake of this wall is shown to increase the aerodynamic loss of the vane. On the other hand, the wall alters secondary flow structures and has a protective effect on the heat transfer in the leading edge-endwall junction, a critical region for component life. The different clocking positions of the vane relative to the combustor wall are tested experimentally and are shown to alter the aerothermal field. The experimental methods and processing techniques adopted in this work are used to highlight the differences between the different cases studied.

Boundary Layer Flashback Limits of Hydrogen-Methane-Air Flames in a Generic Swirl Burner at Gas Turbine Relevant Conditions

2020 ◽  
Author(s):  
Dominik Ebi ◽  
Peter Jansohn
Keyword(s):  
Boundary Layer ◽  
Gas Turbine ◽  
Wall Temperature ◽  
Gas Turbines ◽  
High Speed ◽  
Cooling System ◽  
Atmospheric Conditions ◽  
Preheat Temperature ◽  
Swirl Burner ◽  
Wide Range

Abstract Operating stationary gas turbines on hydrogen-rich fuels offers a pathway to significantly reduce greenhouse gas emissions in the power generation sector. A key challenge in the design of lean-premixed burners, which are flexible in terms of the amount of hydrogen in the fuel across a wide range and still adhere to the required emissions levels, is to prevent flame flashback. However, systematic investigations on flashback at gas turbine relevant conditions to support combustor development are sparse. The current work addresses the need for an improved understanding with an experimental study on boundary layer flashback in a generic swirl burner up to 7.5 bar and 300° C preheat temperature. Methane-hydrogen-air flames with 50 to 85% hydrogen by volume were investigated. High-speed imaging was applied to reveal the flame propagation pathway during flashback events. Flashback limits are reported in terms of the equivalence ratio for a given pressure, preheat temperature, bulk flow velocity and hydrogen content. The wall temperature of the center body along which the flame propagated during flashback events has been controlled by an oil heating/cooling system. This way, the effect any of the control parameters, e.g. pressure, had on the flashback limit was de-coupled from the otherwise inherently associated change in heat load on the wall and thus change in wall temperature. The results show that the preheat temperature has a weaker effect on the flashback propensity than expected. Increasing the pressure from atmospheric conditions to 2.5 bar strongly increases the flashback risk, but hardly affects the flashback limit beyond 2.5 bar.

Validation and Comparison of Strip Seal Designs for Gas Turbine Engine Nozzle Guide Vanes

2008 ◽  
Author(s):  
Arash Farahani ◽  
Peter Childs
Keyword(s):  
Gas Turbine ◽  
Guide Vane ◽  
Gas Turbine Engine ◽  
Experimental Comparison ◽  
Cfd Modelling ◽  
Guide Vanes ◽  
Turbine Engine ◽  
Seal Design ◽  
Nozzle Guide ◽  
Nozzle Guide Vanes

Strip seals are commonly used to prevent or limit leakage flows between nozzle guide vanes (NGV) and other gas turbine engine components that are assembled from individual segments. Leakage flow across, for example, a nozzle guide vane platform, leads to increased demands on the gas turbine engine internal flow system and a rise in specific fuel consumption (SFC). Careful attention to the flow characteristics of strip seals is therefore necessary. The very tight tolerances associated with strip seals provides a particular challenge to their characterisation. This paper reports the validation of CFD modelling for the case of a strip seal under very carefully controlled conditions. In addition, experimental comparison of three types of strip seal design, straight, arcuate, and cloth, is presented. These seals are typical of those used by competing manufacturers of gas turbine engines. The results show that the straight seal provides the best flow sealing performance for the controlled configuration tested, although each design has its specific merits for a particular application.

Failure Analysis of Heavy Industrial Gas Turbine Engine First Stage Nozzel Guide Vane

2012 ◽  
Vol 445 ◽  
pp. 1047-1052
Author(s):  
Alaaeldin H. Mustafa
Keyword(s):  
Failure Analysis ◽  
Gas Turbine ◽  
Guide Vane ◽  
Xrd Analysis ◽  
Optical Microscope ◽  
Guide Vanes ◽  
X Ray ◽  
Nozzle Guide ◽  
Industrial Gas Turbine ◽  
Nozzle Guide Vanes

Failure analysis investigation was conducted on 70 MW set of 1st stage turbine nozzle guide vanes (NGVs) of heavy industrial gas turbine. The failure was investigated using the light optical microscope (LOM), X-ray diffraction analysis (XRD) and energy dispersive X-ray spectroscopy (EDS) in an environmental scanning electron microscope (ESEM). The results of the analysis indicate that the NGVs which were made of Co base superalloy FSX-414 had been operated above the recommended operating hours under different fuel types in addition to inadequate repair process in previous repair removal. The XRD analysis of the fractured areas sample shows presence ofwhich might indicate the prolonged operation at high temperature. Keywords: cobalt-base; nozzle guide vanes, gas turbine.

Film Cooling Research on the Endwall of a Turbine Nozzle Guide Vane in a Short Duration Annular Cascade: Part 1—Experimental Technique and Results

1992 ◽  
Vol 114 (4) ◽  
pp. 734-740 ◽  
Author(s):  
S. P. Harasgama ◽  
C. D. Burton
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Guide Vane ◽  
Density Ratio ◽  
Suction Side ◽  
Coolant Temperature ◽  
Guide Vanes ◽  
Nozzle Guide ◽  
Annular Cascade ◽  
Nozzle Guide Vanes

Heat transfer and aerodynamic measurements have been made on the endwalls of an annular cascade of turbine nozzle guide vanes in the presence of film cooling. The results indicate that high levels of cooling effectiveness can be achieved on the endwalls of turbine nozzle guide vanes (NGV). The NGV were operated at the correct engine nondimensional conditions of Reynolds number, Mach number, gas-to-wall temperature ratio, and gas-to-coolant density ratio. The results show that the secondary flow and horseshoe vortex act on the coolant, which is convected toward the suction side of the NG V endwall passage. Consequently the coolant does not quite reach the pressure side/casing trailing edge, leading to diminished cooling in this region. Increasing the blowing rate from 0.52 to 1.1 results in significant reductions in heat transfer to the endwall. Similar trends are evident when the coolant temperature is reduced. Measured heat transfer rates indicate that over most of the endwall region the film cooling reduces the Nusselt number by 50 to 75 percent.

Aerothermal Performance of Shielded Vane Design

2017 ◽  
Vol 139 (11) ◽  
Author(s):  
Ioanna Aslanidou ◽  
Budimir Rosic
Keyword(s):  
Heat Transfer ◽  
Total Pressure ◽  
High Speed ◽  
Guide Vane ◽  
Leading Edge ◽  
Experimental Facility ◽  
Numerical Studies ◽  
Nozzle Guide Vane ◽  
Inlet Conditions ◽  
Nozzle Guide

This paper presents an experimental investigation of the concept of using the combustor transition duct wall to shield the nozzle guide vane leading edge. The new vane is tested in a high-speed experimental facility, demonstrating the improved aerodynamic and thermal performance of the shielded vane. The new design is shown to have a lower average total pressure loss than the original vane, and the heat transfer on the vane surface is overall reduced. The peak heat transfer on the vane leading edge–endwall junction is moved further upstream, to a region that can be effectively cooled as shown in previously published numerical studies. Experimental results under engine-representative inlet conditions showed that the better performance of the shielded vane is maintained under a variety of inlet conditions.

An Impact Assessment of Erosion of Nozzle Guide Vanes and Rotor Blades on Aerodynamic Performance of a Gas Turbine by CFD

2019 ◽  
Author(s):  
Koichi Yonezawa ◽  
Masahiro Takayasu ◽  
Genki Nakai ◽  
Kazuyasu Sugiyama ◽  
Katsuhiko Sugita ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Rotor Blade ◽  
Cfd Simulation ◽  
Rotor Blades ◽  
Total Power ◽  
Guide Vanes ◽  
Turbine Performance ◽  
Nozzle Guide ◽  
Nozzle Guide Vanes

Abstract Nozzle guide vanes (NGVs) and rotor blades deteriorate due to erosion, and this may affect the aerodynamic characteristics of gas turbines. According to previous studies, the erosion of first-stage NGVs significantly affected the blade loading of the first-stage rotor. An increase in the tip gap also may significantly affect the gas turbine performance. In the present study, numerical investigations have been carried out using a real eroded nozzle and blade geometries for two purposes. One purpose was to clarify the influences underlying the deterioration of the nozzle and the rotor blade, such as the effects on the erosion of NGVs in the first stage and the effects of the tip gap on the gas turbine performance. The other was to develop a method to estimate the total gas turbine performance using a CFD simulation and a heat balance analysis. The results show that the erosion of NGV leads to an increased flow rate and affects the operating condition of the gas turbine cycle. This, in turn, can decrease the total thermal efficiency. The experimental results suggest that an increase in the tip gap width decreases rotor output almost linearly, and the numerical results showed the same tendency. The influence of the tip gap in the real gas turbine condition was also examined, revealing that an increase in the tip gap leads to an increase in the pressure loss in the nozzle downstream as well as around the rotor blade itself. Consequently, the total power output and the isentropic efficiency of the turbine decreased.

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