FLOvane: A New Approach for High-Pressure Vane Design

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Dingxi Wang ◽  
Francesco Ornano ◽  
Yan Sheng Li ◽  
Roger Wells ◽  
Christer Hjalmarsson ◽  
...  
Keyword(s):  
High Pressure ◽  
Gas Turbines ◽  
Fluid Dynamic ◽  
Flow Path ◽  
Secondary Flows ◽  
Cooling Flow ◽  
Starting Point ◽  
Industrial Gas Turbines ◽  
Improved Performance ◽  
Cfd Analyses

This paper presents a new unconventional philosophy for high-pressure (HP) vane design. It is proposed that the most natural design starting point for admitting and accelerating flow with minimum loss and secondary flow is a trumpet-shaped flow-path which gradually turns to the desired angle. Multiple trumpet-shaped inlets are seamlessly blended into the (annular or partitioned) combustor walls resulting in a highly lofted flow-path, rather than a traditional flow-path defined by distinct airfoil and endwall surfaces. We call this trumped-shaped inlet the fully lofted oval vane (FLOvane). The purpose of this paper is to describe the FLOvane concept and to present back-to-back CFD analyses of two current industrial gas turbines with conventional and FLOvane-modified designs. The resulting designs diverge significantly from conventional designs in terms of both process and final geometric form. Computational fluid dynamic predictions for the FLOvane-modified designs show improved aerodynamic performance characteristics, reduced heat load, improved cooling performance, improved thermal–mechanical life, and improved stage/engine efficiency. The mechanisms for improved performance include reduction of secondary flows, reduced mixing of coolant flow with the mainstream flow, reduced skin friction, and improved coolant distribution. In the two current industrial gas turbine engines, the absolute (percentage point) improvement in stage isentropic efficiency when the FLOvane design was included was estimated at 0.33% points and 0.40% points without cooling flow reduction, and 1.5% points in one case and much more is expected for the other case when cooling flow reductions were accounted for.

FLOvane: A New Approach for HP Vane Design

2016 ◽  
Author(s):  
Dingxi Wang ◽  
Francesco Ornano ◽  
Yan Sheng Li ◽  
Roger Wells ◽  
Christer Hjalmarsson ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Cooling System ◽  
Flow Analysis ◽  
Leading Edge ◽  
Flow Path ◽  
Secondary Flows ◽  
Minimum Loss ◽  
Good Argument ◽  
Starting Point ◽  
2D Airfoil

The University of Oxford has been working for a number of years on a conceptually new philosophy for HP vane design [1]. The desired function of the HP vane is to accept flow from a — generally — annular intake, and turn and accelerate it with minimum loss and heat transfer, and with due consideration to mechanical, manufacturing and integration issues. The conventional design process is well-defined: annulus line definition; through-flow analysis; 2D airfoil section definition; vane stack definition; lean/sweep treatments; secondary flow contouring and fillet design; vane and platform cooling system design; integrated aero/thermal/capacity optimization. The process is based on optimizing 2D airfoil stacks to control secondary flows. More recent research (last 20 years) has led to better understanding of airfoil lean, airfoil sweep, leading edge treatments and end-wall profiling. There may be some iterative optimization in which the airfoil sections themselves are modified, but these treatments (as implied by the terminology) are essentially modifications to a 2D airfoil stack which interrupts the upstream annular (most aero-engines) or can-partitioned (most land-based gas turbines) duct. It is proposed that a more natural design starting point for admitting and accelerating flow with minimum loss (etc.) is a trumpet-shaped flow-path which gradually turns to the desired angle. This approach rejects many traditional concepts in aerodynamics (the sacrosanct nature of the airfoil, concepts of good and bad lift distributions, concepts of vane and platform, etc.), and focuses our attention on the design of a highly-lofted flow-path. The purpose of this paper is to show that there may be merit in reappraising the starting point for HP vane design, and in investigating Fully Lofted Oval vane (FLOvane) forms of the type described. The corresponding author has not yet heard a good argument against the proposed design philosophy. Despite significantly diverging from conventional wisdom in terms of both process and final geometric form, the following advantages are claimed: improved aerodynamic loss characteristics, reduced heat load, improved cooling performance, improved thermal-mechanical life, improved stage/engine efficiency. The claimed advantages are justified with detailed numerical analyses of two current industrial gas turbines, compared back-to-back with modified turbines incorporating unoptimised FLOvane designs. Significant performance improvements were observed when FLOvane designs were used.

A Method to Evaluate the Sensitivity of Aerodynamic Damping to Mode Shape Perturbations

2019 ◽  
Author(s):  
Jing Li ◽  
Suryarghya Chakrabarti ◽  
Wei-Min Ren
Keyword(s):  
Mode Shape ◽  
Gas Turbines ◽  
Fluid Dynamic ◽  
Computational Cost ◽  
Assessment Process ◽  
Mode Shapes ◽  
Shape Sensitivity ◽  
Aerodynamic Damping ◽  
Damped System ◽  
Cfd Analyses

Abstract Turbomachinery blade mode shapes are routinely predicted by finite element method (FEM) programs and are then used in unsteady computational fluid dynamic (CFD) analyses to predict the aerodynamic damping. This flutter stability assessment process is critical for the last-stage blades (LSBs) of modern heavy-duty gas turbines (HDGTs) which can be particularly susceptible to flutter. Evidences suggest that actual mode shapes may deviate from the FEM predictions due to changes in the FEM boundary or loading conditions, effects of the nonlinear friction contacts, and blade-to-blade variations (mistuning), among others. This uncertainty in the mode shape is accompanied by a general lack of knowledge on the sensitivity of the aerodynamic damping to a small change in mode shape. This paper presents a method to perturb a mode shape and estimate the corresponding change in aerodynamic damping in a framework enabled by linear theories and a rigid-body, quasi-3D treatment of mode shapes. This method is of low computational cost and is suitable for use in the preliminary design cycle. The numerical validation and applications of the method are demonstrated on two LSB blades. Results suggest that the mode shape sensitivity can be substantial and may even exceed the change in aerodynamic damping of a frictionally damped system when subjected to various levels of excitation.

Biodiesel as an Alternative Fuel in Siemens Dry Low Emissions Combustors: Atmospheric and High Pressure Rig Testing

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Kexin Liu ◽  
John P. Wood ◽  
Eoghan R. Buchanan ◽  
Pete Martin ◽  
Victoria E. Sanderson
Keyword(s):  
High Pressure ◽  
Gas Turbines ◽  
Alternative Fuel ◽  
Test Results ◽  
Combustion Dynamics ◽  
Pressure Drops ◽  
Air Inlet ◽  
Air Temperatures ◽  
Measured Probability ◽  
Industrial Gas Turbines

Atmospheric and high pressure rig tests were conducted to investigate the feasibility of using biodiesel as an alternative fuel to power industrial gas turbines in one of the world’s leading dry low emissions (DLE) combustion systems, the SGT-100. At the same conditions, tests were also carried out for mineral diesel to provide reference information to evaluate biodiesel as an alternative fuel. In atmospheric pressure rig tests, the likelihood of the machine lighting was identified based on the measured probability of the ignition of a single combustor. Lean ignition and extinction limits at various air temperatures were also investigated with different air assist pressures. The ignition test results reveal that reliable ignition can be achieved with biodiesel across a range of air mass flow rates and air fuel ratios (AFRs). In high pressure rig tests, emissions and combustion dynamics were measured for various combustor air inlet pressures, temperatures, combustor wall pressure drops, and flame temperatures. These high pressure rig results show that biodiesel produced less NOx than mineral diesel. The test results indicate that the Siemens DLE combustion system can be adapted to use biodiesel as an alternative fuel without major modification.

Advanced Catalytic Pilot for Low NOx Industrial Gas Turbines

2002 ◽  
Author(s):  
Hasan Karim ◽  
Kent Lyle ◽  
Shahrokh Etemad ◽  
Lance Smith ◽  
William Pfefferle ◽  
...  
Keyword(s):  
High Pressure ◽  
Surface Temperature ◽  
Gas Turbines ◽  
Lean Burn ◽  
Pressure Testing ◽  
Wide Range ◽  
Industrial Gas Turbines ◽  
Design And Testing ◽  
Pilot Burner ◽  
Load Conditions

This paper describes the design and testing of a catalytically-stabilized pilot burner for current and advanced Dry Low NOx (DLN) gas turbine combustors. In this paper, application of the catalytic pilot technology to industrial engines is described using Solar Turbines’ Taurus 70 engine. The objective of the work described is to develop the catalytic pilot technology and document the emission benefits of catalytic pilot technology when compared to higher, NOx producing pilots. The catalytic pilot was designed to replace the existing pilot in the existing DLN injector without major modification to the injector. During high pressure testing, the catalytic pilot showed no incidence of flashback or autoignition while operating over wide range of combustion temperatures. The catalytic reactor lit off at a temperature of approximately 598K (325°C/617°F) and operated at simulated 100% and 50% load conditions without a preburner. At high pressure, the maximum catalyst surface temperature was similar to that observed during atmospheric pressure testing and considerably lower than the surface temperature expected in lean-burn catalytic devices. In single injector rig testing, the integrated assembly of the catalytic pilot and Taurus 70 injector demonstrated NOx and CO emission less than 5 ppm @ 15% O2 for 100% and 50% load conditions along with low acoustics. The results demonstrate that a catalytic pilot burner replacing a diffusion flame or partially-premixed pilot in an otherwise DLN combustor can enable operation at conditions with substantially reduced NOx emissions.

Quantitative Computational Fluid Dynamic Analyses of Particle Deposition on a Transonic Axial Compressor Blade—Part II: Impact Kinematics and Particle Sticking Analysis

2014 ◽  
Vol 137 (2) ◽  
Author(s):  
Alessio Suman ◽  
Mirko Morini ◽  
Rainer Kurz ◽  
Nicola Aldi ◽  
Klaus Brun ◽  
...  
Keyword(s):  
Computational Fluid Dynamic ◽  
Gas Turbines ◽  
Fluid Dynamic ◽  
Axial Compressor ◽  
Particle Impact ◽  
High Tendency ◽  
Compressor Rotor ◽  
Kinematic Characteristics ◽  
Starting Point ◽  
The Impact

In heavy-duty gas turbines, the microparticles that are not captured by the air filtration system can cause fouling and, consequently, a performance drop of the compressor. This paper presents three-dimensional numerical simulations of the microparticle ingestion (0 μm–2 μm) on an axial compressor rotor carried out by means of a commercial computational fluid dynamic (CFD) code. Particle trajectory simulations use a stochastic Lagrangian tracking method that solves the equations of motion separately from the continuous phase. The NASA Rotor 37 is considered as a case study for the numerical investigation. The compressor rotor numerical model and the discrete phase model were previously validated by the authors in the first part of this work. The kinematic characteristics (velocity and angle) of the impact of micrometric and submicrometric particles with the blade surface of an axial transonic compressor are shown. The blade zones affected by particle impact were extensively analyzed and reported in the first part of this work, forming the starting point for the analyses shown in this paper. The kinematic analysis showed a high tendency of particle adhesion on the suction side (SS), especially for the particles with a diameter equal to 0.25 μm. Fluid dynamic phenomena and airfoil shape play a key role regarding particle impact velocity and angle. This work has the goal of combining, for the first time, the kinematic characteristics of particle impact on the blade with fouling phenomenon by the use of a quantity called sticking probability (SP) adopted from literature. From these analyses, some guidelines for a proper management of the power plant (in terms of filtration and washing strategies) are highlighted.

Combustion System Development and Testing for MAN’s New Industrial Gas Turbines MGT 6100 and MGT 6200

2014 ◽  
Author(s):  
Frank Reiss ◽  
Sven-Hendrik Wiers ◽  
Ulrich Orth ◽  
Emil Aschenbruck ◽  
Martin Lauer ◽  
...  
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Test Facility ◽  
Combustion System ◽  
Test Rig ◽  
Low Emission ◽  
Pressure Test ◽  
Industrial Gas Turbines ◽  
And Performance

This paper describes the development and test results of the low emission combustion system for the new industrial gas turbines in the 6–7 MW class from MAN Diesel & Turbo. The design of a robust combustion system and the achievement of very low emission targets were the most important design goals of the combustor development. During the design phase, the analysis of the combustor (i.e. burner design, air distribution, liner cooling design) was supported with different CFD tools. This advanced Dry Low Emission can combustion system (ACC) consists of 6 cans mounted externally on the gas turbine. The behavior and performance of a single can sector was tested over a wide load range and with different boundary conditions; first on an atmospheric test rig and later on a high pressure test rig with extensive instrumentation to ensure an efficient test campaign and accurate data. The atmospheric tests showed a very good performance for all combustor parts and promising results. The high pressure tests demonstrated very stable behavior at all operation modes and very low emissions to satisfy stringent environmental requirements. The whole operation concept of the combustion system was tested first on the single-can high pressure test bed and later on twin and single shaft gas turbines at MAN’s gas turbine test facility. During the engine tests, the can combustors demonstrated the expected combustion performance under real operation conditions. All emissions and performance targets were fully achieved. On the single shaft engine, the combustors were running with single digit ppm NOx levels between 50% and 100% load. The validation phase and further optimization of the gas turbines and the engine components are ongoing. The highlights of the development process and results of the combustor and engine tests will be presented and discussed within this paper.

Numerical Analysis on the Impact of Inter-Stage Flow Addition in a High-Pressure Steam Turbine

2017 ◽  
Author(s):  
Soo Young Kang ◽  
Jeong Jin Lee ◽  
Tong Seop Kim ◽  
Seong Jin Park ◽  
Gi Won Hong
Keyword(s):  
High Pressure ◽  
Dynamic Characteristics ◽  
Computational Analysis ◽  
Fluid Dynamic ◽  
Flow Path ◽  
High Pressure Turbine ◽  
Flow Paths ◽  
Second Stage ◽  
Third Stage ◽  
Computational Analyses

This paper presents the analysis results of the fluid dynamic characteristics when steam is supplied through an overload valve to the second and third stages of an ultra-supercritical (USC) high-pressure turbine. Firstly, a single-passage computational analysis by using a simple model of an admission flow path, and a single passage for the second and third stages of the USC high-pressure turbine was performed. Computational analysis was conducted to determine the fluid dynamic characteristics exhibited when the second-stage outlet flow, that is, the main flow between the second-stage outlet and third-stage inlet, and the admission flow are being mixed. The mixing causes complex flow phenomena such as swirl, and the velocity vector of the main flow changes. This, in turn, causes a pressure drop between the second-stage outlet and third-stage inlet, potentially affecting the performance of the turbine. The actual flow in the overload valve is supplied through the admission flow path, which has the shape of a casing circumferentially surrounding the turbine, after passing through the valve and flowing in two directions perpendicular to the turbine axis. This necessitates full-passage computational analyses of the entire turbine and the flow paths of the overload valve. To achieve this, we implemented a full 3-D geometric modeling of the admission flow path, and conducted full-passage computational analyses of the fluid dynamic characteristics of all the flow paths including those of the second and third stages of the USC high-pressure turbine, focusing on the pressure drop occurring in the flow path of the overload valve. Furthermore, the results by the single and full-passage computational analyses were compared and the effects of two different methodological approaches on the results of the computational analysis were analyzed.

Characterization of Metallic W-Seals for Inner to Outer Shroud Sealing in Industrial Gas Turbines

2012 ◽  
Author(s):  
Neelesh Sarawate ◽  
Chris Wolfe ◽  
Ibrahim Sezer ◽  
Ryan Ziegler ◽  
Raymond Chupp
Keyword(s):  
Gas Turbines ◽  
Weighted Average ◽  
Cost Effective ◽  
Secondary Flows ◽  
Operating Conditions ◽  
Pressure Differential ◽  
Flow Models ◽  
Operational Life ◽  
Industrial Gas Turbines ◽  
Stage 1

Sealing and clearance control are two of the most cost effective methods to reach desired goals of efficiency, power output, operational life and emission levels in turbomachinery. Metallic seals such as W seals are widely used in gas turbines to seal axial gaps between adjacent static components such as shrouds and nozzles. Often the seals are characterized in a laboratory controlled environment, and the test results are used in modeling the secondary flows. However in real operating conditions, the static components can shift relative to each other creating misalignments that result in non-uniform sealing surfaces. One such application includes sealing between the stage 1 outer and inner shrouds. The inner shrouds are often stacked with axial misalignments relative to the neighboring shrouds due to manufacturing and assembly tolerances. Characterizing the effect of shroud misalignments on the W seal leakage is reported in this article. A comprehensive test matrix is conducted to characterize W seal leakage for four different magnitudes of shroud offsets, three types of seals having varying stiffness, and two compression levels. It is observed that the W seal leakage is fairly insensitive to the compression levels and the type of seal at zero misalignments. The seal leakage increases substantially with misalignments up to four times than for a perfectly aligned condition. The seal behavior also changes with increasing offsets. The seal exhibits typical properties of a positively loaded member for small misalignments, however, the behavior resembles a loose seal for larger misalignments. For a positively loaded seal, the effective clearance of the seal increases with pressure differential, whereas in case of a loose seal, the effective clearance decreases with increasing pressure differential. The effect of misalignments must be considered when modeling the seal in the engine flow models using a weighted average of the effective clearance.

Advanced Catalytic Pilot for Low NOx Industrial Gas Turbines

2003 ◽  
Vol 125 (4) ◽  
pp. 879-884 ◽  
Author(s):  
H. Karim ◽  
K. Lyle ◽  
S. Etemad ◽  
L. L. Smith ◽  
W. C. Pfefferle ◽  
...  
Keyword(s):  
High Pressure ◽  
Surface Temperature ◽  
Gas Turbines ◽  
Lean Burn ◽  
Pressure Testing ◽  
Wide Range ◽  
Industrial Gas Turbines ◽  
Design And Testing ◽  
Pilot Burner ◽  
Load Conditions

This paper describes the design and testing of a catalytically stabilized pilot burner for current and advanced Dry Low NOx (DLN) gas turbine combustors. In this paper, application of the catalytic pilot technology to industrial engines is described using Solar Turbines’ Taurus 70 engine. The objective of the work described is to develop the catalytic pilot technology and document the emission benefits of catalytic pilot technology when compared to higher, NOx producing pilots. The catalytic pilot was designed to replace the existing pilot in the existing DLN injector without major modification to the injector. During high-pressure testing, the catalytic pilot showed no incidence of flashback or autoignition while operating over wide range of combustion temperatures. The catalytic reactor lit off at a temperature of approximately 598 K (325°C/617°F) and operated at simulated 100% and 50% load conditions without a preburner. At high pressure, the maximum catalyst surface temperature was similar to that observed during atmospheric pressure testing and considerably lower than the surface temperature expected in lean-burn catalytic devices. In single-injector rig testing, the integrated assembly of the catalytic pilot and Taurus 70 injector demonstrated NOx and CO emission less than 5 ppm @ 15% O2 for 100% and 50% load conditions along with low acoustics. The results demonstrate that a catalytic pilot burner replacing a diffusion flame or partially premixed pilot in an otherwise DLN combustor can enable operation at conditions with substantially reduced NOx emissions.

Experimental Investigation of Purge Flow Effects on a High Pressure Turbine Stage

2014 ◽  
Vol 137 (4) ◽  
Author(s):  
K. Regina ◽  
A. I. Kalfas ◽  
R. S. Abhari
Keyword(s):  
Experimental Investigation ◽  
High Pressure ◽  
Gas Turbines ◽  
Radial Displacement ◽  
Secondary Flows ◽  
Turbine Stage ◽  
Flow Factor ◽  
Purge Flow ◽  
The Impact ◽  
Stage Efficiency

In the present paper, an experimental investigation of the effects of rim seal purge flow on the performance of a highly loaded axial turbine stage is presented. The test configuration consists of a one-and-a-half stage, unshrouded, turbine, with a blading representative of high pressure (HP) gas turbines. Efficiency measurements for various purge flow injection levels have been carried out with pneumatic probes at the exit of the rotor and show a reduction of isentropic total-to-total efficiency of 0.8% per percent of injected mass flow. For three purge flow conditions, the unsteady aerodynamic flow field at rotor inlet and rotor exit has been measured with the in-house developed fast response aerodynamic probe (FRAP). The time-resolved data show the unsteady interaction of the purge flow with the secondary flows of the main flow and the impact on the radial displacement of the rotor hub passage vortex (HPV). Steady measurements at off-design conditions show the impact of the rotor incidence and of the stage flow factor on the resulting stage efficiency and the radial displacement of the rotor HPV. A comparison of the effect of purge flow and of the off-design conditions on the rotor incidence and stage flow factor shows that the detrimental effect of the purge flow on the stage efficiency caused by the radial displacement of the rotor HPV is dominated by the increase of stage flow factor in the hub region rather than by the increase of negative rotor incidence.

Sign in / Sign up

Export Citation Format

Share Document