Advanced Turbine Aerodynamic Design Utilizing a Full Stage CFD

2006 ◽  
Author(s):  
Eisaku Ito ◽  
Sunao Aoki ◽  
Akimasa Muyama ◽  
Junichiro Masada
Keyword(s):  
Gas Turbines ◽  
Total Pressure ◽  
Flow Behavior ◽  
Tip Clearance ◽  
Test Facility ◽  
Design Parameters ◽  
Design System ◽  
Aerodynamic Design ◽  
Flow Angle ◽  
Temperature Distributions

Gas turbines for power generation are required to operate more efficiently than ever before for both economic and environmental reasons. Because of this situation, an advanced multistage turbine design and optimization system is required to improve upon existing turbine designs where viscous CFD codes had already been applied on a single row or single stages basis. An advanced CFD code for multistage design applications has been developed at Mitsubishi Heavy Industries (MHI) and has been applied to the redesign of a four stage single shaft turbine. The front 3 stages of the turbine are highly cooled using about 20% cooling air. The outstanding performance of this redesigned turbine has been demonstrated at MHI’s engine test facility. This paper focuses on the customization of the Denton code [5] for industrial usage, the validation of the customized code employing experimental data, and finally the use of the code in executing a successful redesign. Code development and validation are discussed in terms of prediction accuracy for the basic aerodynamic design parameters such as exit flow angle and cascade losses. Through-flow design parameters such as pressure ratio and reaction of each stage are also addressed. Especially important in modern high temperature turbines is the location and distribution of cooling and leakage air being introduced into the main gas-path. The proper treatment of these flows is very important because of the mixing losses and the temperature migration downstream. These important considerations in any analysis approach are discussed and it is shown how they are treated in the customized CFD code. Consistency between the customized CFD code and other parts of the existing aerodynamic design procedure are carefully examined. This is important because aerodynamic parameters have different modeling fidelities in the different parts of the design system. Computer execution times are a very important consideration when utilizing advanced CFD codes. This issue is addressed from the perspective of an industrial design organization. In validating the customized code, special attention was placed on tip clearance leakage flow behavior and seal air migration from the hub wall. Local changes of total pressure and temperature distributions affect the local velocity triangles and local static pressure distributions on the airfoil and end-wall surfaces. Airfoil section geometry and three-dimensional stacking to maximize the turbine efficiency are also considered and discussed. The validated code was subsequently used to execute a redesign of a large frame industrial turbine. This is discussed in some detail. The redesigned turbine has completed full scale engine testing and has been shown to have met all design goals. The CFD predictions are compared with special measurements taken in the engine such as the inter-stage span-wise total pressure and temperature distributions as well as the efficiency trend versus engine load. These comparisons prove the capability of the advanced multistage CFD code.

Robust Compressor Blades for Desensitizing Operational Tip Clearance Variations

2014 ◽  
Author(s):  
Pranay Seshadri ◽  
Shahrokh Shahpar ◽  
Geoffrey T. Parks
Keyword(s):  
Robust Design ◽  
Total Pressure ◽  
Pressure Rise ◽  
Side Surface ◽  
Tip Clearance ◽  
Design Parameters ◽  
Compressor Blades ◽  
Robust Designs ◽  
Multi Objective ◽  
Mean And Variance

Robust design is a multi-objective optimization framework for obtaining designs that perform favorably under uncertainty. In this paper robust design is used to redesign a highly loaded, transonic rotor blade with a desensitized tip clearance. The tip gap is initially assumed to be uncertain from 0.5 to 0.85% span, and characterized by a beta distribution. This uncertainty is then fed to a multi-objective optimizer and iterated upon. For each iteration of the optimizer, 3D-RANS computations for two different tip gaps are carried out. Once the simulations are complete, stochastic collocation is used to generate mean and variance in efficiency values, which form the two optimization objectives. Two such robust design studies are carried out: one using 3D blade engineering design parameters (axial sweep, tangential lean, re-cambering and skew) and the other utilizing suction and pressure side surface perturbations (with bumps). A design is selected from each Pareto front. These designs are robust: they exhibit a greater mean efficiency and lower variance in efficiency compared to the datum blade. Both robust designs were also observed to have significantly higher aft and reduced fore tip loading. This resulted in a weaker clearance vortex, wall jet and double leakage flow, all of which lead to reduced mixed-out losses. Interestingly, the robust designs did not show an increase in total pressure at the tip. It is believed that this is due to a trade-off between fore-loading the tip and obtaining a favorable total pressure rise and higher mixed-out losses, or aft-loading the tip, obtaining a lower pressure rise and lower mixed-out losses.

scholarly journals Numerical and Experimental Investigations on Optimized 3D Compressor Airfoils

2018 ◽  
Author(s):  
Jan Mihalyovics ◽  
Christian Brück ◽  
Dieter Peitsch ◽  
Ilias Vasilopoulos ◽  
Marcus Meyer
Keyword(s):  
Pressure Loss ◽  
Total Pressure ◽  
Experimental Studies ◽  
Total Pressure Loss ◽  
Design Parameters ◽  
Flow Conditions ◽  
Flow Angle ◽  
Flow Phenomena ◽  
The Impact ◽  
Stator Design

The objective of the presented work is to perform numerical and experimental studies on compressor stators. This paper presents the modification of a baseline stator design using numerical optimization resulting in a new 3D stator. The Rolls Royce in-house compressible flow solver HYDRA was employed to predict the 3D flow, solving the steady RANS equations with the Spalart-Allmaras turbulence model, and its corresponding discrete adjoint solver. The performance gradients with respect to the input design parameters were used to optimize the stator blade with respect to the total pressure loss over a prescribed incidence range, while additionally minimizing the flow deviation from the axial direction at the stator exit. Non-uniform profile boundary conditions, being derived from the experimental measurements, have been defined at the inlet of the CFD domain. The presented results show a remarkable decrease in the axial exit flow angle deviation and a minor decrease in the total pressure loss. Experiments were conducted on two compressor blade sets investigating the three-dimensional flow in an annular compressor stator cascade. Comparing the baseline flow of the 42° turning stator shows that the optimized stator design minimizes the secondary flow phenomena. The experimental investigation discusses the impact of steady flow conditions on each stator design while focusing on the comparison of the 3D optimized design to the baseline case. The flow conditions were investigated using five-hole probe pressure measurements in the wake of the blades. Furthermore, oil-flow visualization was applied to characterize flow phenomena. These experimental results are compared with the CFD calculations.

scholarly journals Impact of a Cooled Cooling Air System on the External Aerodynamics of a Gas Turbine Combustion System

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
A. Duncan Walker ◽  
Bharat Koli ◽  
Liang Guo ◽  
Peter Beecroft ◽  
Marco Zedda
Keyword(s):  
Gas Turbines ◽  
Pressure Loss ◽  
Total Pressure ◽  
Outer Wall ◽  
Total Pressure Loss ◽  
Test Facility ◽  
Combustion System ◽  
Air System ◽  
External Aerodynamics ◽  
Cooling Air

To manage the increasing turbine temperatures of future gas turbines a cooled cooling air system has been proposed. In such a system some of the compressor efflux is diverted for additional cooling in a heat exchanger (HX) located in the bypass duct. The cooled air must then be returned, across the main gas path, to the engine core for use in component cooling. One option is do this within the combustor module and two methods are examined in the current paper; via simple transfer pipes within the dump region or via radial struts in the prediffuser. This paper presents an experimental investigation to examine the aerodynamic impact these have on the combustion system external aerodynamics. This included the use of a fully annular, isothermal test facility incorporating a bespoke 1.5 stage axial compressor, engine representative outlet guide vanes (OGVs), prediffuser, and combustor geometry. Area traverses of a miniature five-hole probe were conducted at various locations within the combustion system providing information on both flow uniformity and total pressure loss. The results show that, compared to a datum configuration, the addition of transfer pipes had minimal aerodynamic impact in terms of flow structure, distribution, and total pressure loss. However, the inclusion of prediffuser struts had a notable impact increasing the prediffuser loss by a third and consequently the overall system loss by an unacceptable 40%. Inclusion of a hybrid prediffuser with the cooled cooling air (CCA) bleed located on the prediffuser outer wall enabled an increase of the prediffuser area ratio with the result that the system loss could be returned to that of the datum level.

scholarly journals The Model V84.3 Shot Tests: Compressor Flow Field Measurements and Evaluation

1994 ◽  
Author(s):  
M. Janssen ◽  
R. Mönig ◽  
J. Seume ◽  
H. Hönen ◽  
R. Lösch-Schloms ◽  
...  
Keyword(s):  
Flow Field ◽  
Total Pressure ◽  
Static Pressure ◽  
Pressure Rise ◽  
Full Scale ◽  
Test Facility ◽  
Design Calculation ◽  
Flow Measurements ◽  
Flow Angle ◽  
Probe Measurements

Detailed experimental investigations were carried out at the Siemens test-facility in Berlin to validate and develop further the compressor design of the Model V84.3 gas turbine and to generate a comprehensive data base for the verification of the flow calculation programs. The test facility enables Siemens to confirm the design with regard to performance and reliability in the full scale machine under full load and off-design condition. Various measuring techniques well established in the laboratory were applied to the full scale compressor to examine the flow field. Along with rather conventional 5-hole probes for measuring the flow field in the core region, miniaturized 3-hole probes were developed at the Turbomachinery Laboratory of the Technical University of Aachen, tested and finally used for the measurements of endwall boundary layer profiles and their development throughout the compressor. In addition to the probe measurements, wall static-pressure measurements, as well as probed vane measurements, were carried out. The paper briefly describes the test facility, the compressor under investigation, and the instrumentation for the flow measurements. A comparison of the 3-hole and 5-hole probe measurements is presented. The experimental results are compared with calculated results taken from a two-dimensional off-design calculation program with standard loss models. By means of the measured static-pressure rise at the casing wall and the total pressure distributions downstream of the rotor rows, a modification of the loss modeling was performed. The calculated flow field is compared to the results of the 3-hole and 5-hole probe measurements in terms of radial distributions for flow angle. Mach number and total pressure.

Numerical Visualization of Water-Vapor Flow Configurations in Fusion Reactors During Ingress of Coolant Events

2002 ◽  
Author(s):  
Yasuo Ose ◽  
Kazuyuki Takase ◽  
Hiroyuki Yoshida ◽  
Hajime Akimoto
Keyword(s):  
Water Vapor ◽  
Flow Behavior ◽  
Test Facility ◽  
Design Parameters ◽  
Fusion Reactors ◽  
Vapor Flow ◽  
Two Phase ◽  
Validation Data ◽  
Flow Configurations ◽  
Suppression System

An integrated Ingress-of-Coolant Event (ICE) test facility was constructed to demonstrate that the International Thermonuclear Experimental Reactor (ITER) safety design approach and design parameters for the ICE are adequate. Major objectives of the integrated ICE test facility are to estimate the performance of an integrated pressure suppression system and obtain the validation data for safety analysis codes for fusion reactors. The integrated ICE test facility simulates the current ITER components with a scaling factor of 1/1600. The modified Transient Reactor Analysis Code (TRAC) is used to verify the integrated ICE test results and clarify quantitatively the two-phase flow behavior in ITER during the ICE. From the results of the present study the effectiveness of the ITER pressure suppression system was verified experimentally, and then, water-vapor flow configurations in ITER at the ICE were visualized numerically by the three-dimensional computations using the modified TRAC.

scholarly journals Effect of Relative Velocity Distribution on Efficiency and Exit Flow of Centrifugal Impellers

1983 ◽  
Author(s):  
H. Mishina ◽  
H. Nishida
Keyword(s):  
Total Pressure ◽  
Flow Behavior ◽  
Design Parameters ◽  
One Dimensional ◽  
Pressure Losses ◽  
Loss Analysis ◽  
High Stage ◽  
The Relationship ◽  
Stage Efficiency ◽  
Wide Operating

The major problem for designing centrifugal compressors is to attain high stage efficiency as well as a wide operating range. High stage efficiency is customarily attained by the optimization of design parameters using a one-dimensional loss analysis including the relationship between the flow behavior and total pressure losses for limited types of compressors.

The Development of a Hot Section Eddy Current Sensor for Turbine Tip Clearance Measurement

2013 ◽  
Author(s):  
K. S. Chana ◽  
M. T. Cardwell ◽  
J. S. Sullivan
Keyword(s):  
Eddy Current ◽  
Gas Turbines ◽  
High Speed ◽  
Elevated Temperatures ◽  
Tip Clearance ◽  
Test Facility ◽  
Current Sensor ◽  
Integrated Sensor ◽  
Eddy Current Sensor ◽  
Turbine Efficiency

Gas turbine efficiency can be improved with tighter turbine tip clearances. An approach being developed by engine manufacturers deploys active tip clearance monitoring where the turbine casing diameter is actively controlled in-service either mechanically or thermally. Typically current engines operate at about 1% clearance of blade span. With active control this could potentially be reduced significantly. Ideally active tip clearance control requires closed loop feedback measurements to maintain very small clearances without the risk of blade tip contact with the casing liner. Therefore reliable and robust sensors systems are required that can operate at the elevated temperatures found in modern gas turbines. Currently there are limited sensor systems available that can operate at these temperatures and survive typical sensor life requirements of many thousands of hours. This study details development of a high temperature eddy current sensor system for hot section applications. The investigation encompasses development and validation of an integrated sensor design to provide tip clearance measurements. The sensor is designed to withstand temperatures of order 1500 to 1600K. Test facilities used to validate the system include a RB168 Mk 101 Spey engine and a Rolls-Royce VIPER engine. The turbine casings of both engines were modified to fit sensors directly above the rotor. The accuracy of the system was validated in a high speed rotor test facility with engine representative blading. Accuracy of the eddy current sensor was compared and validated against a dynamic laser micrometer system.

scholarly journals Investigation of Wash Fluid Preheating on the Effectiveness of Online Compressor Washing in Industrial Gas Turbines

2020 ◽  
Author(s):  
Roupa Agbadede ◽  
Biweri Kainga
Keyword(s):  
Gas Turbines ◽  
Pressure Loss ◽  
Total Pressure ◽  
Loss Coefficient ◽  
Total Pressure Loss ◽  
Compressor Cascade ◽  
Flow Angle ◽  
Pressure Loss Coefficient ◽  
Industrial Gas Turbines ◽  
Total Pressure Loss Coefficient

Abstract This study presents an investigation of wash fluid preheating on the effectiveness of online compressor washing in industrial gas turbines. Crude oil was uniformly applied on the compressor cascade blades surfaces using a roller brush, and carborundum particles were ingested into the tunnel to create accelerated fouled blades. Demineralized water was preheated to 500C using the heat coil provided in the tank. When fouled blades washed with preheated demineralized and the one without preheating were compared, it was observed that there was little or no difference in terms of total pressure loss coefficient and exit flow angle. However, when the fouled and washed cases were compared, there was a significant different in total pressure loss coefficient and exit flow angle.

The Three-Dimensional Aerodynamic Design and Test of a Three-Stage Transonic Compressor

1999 ◽  
Author(s):  
Y. S. Li ◽  
R. G. Wells
Keyword(s):  
Gas Turbines ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Design System ◽  
Test Results ◽  
Aerodynamic Design ◽  
Circular Arc ◽  
Transonic Compressor ◽  
Performance Improvements ◽  
Conventional Design

This paper presents the aerodynamic design and initial test results from a three-stage transonic compressor developed by ALSTOM Gas Turbines Ltd. The Advanced Transonic Compressor (ATC) was designed using a design system based on three-dimensional (3D) Navier-Stokes CFD codes in contrast to the more conventional design approach centred around the use of throughflow and blade to blade solvers. The customised 3D multiple-circular-arc (MCA) and controlled-diffusion (CD) airfoils have replaced the double-circular-arc (DCA) profiles used previously. The use of both single row and multistage 3D CFD codes has enabled the potential performance improvements from the application of new blade designs to be predicted and comparisons between conventional and new blades to be made. Rig test results have confirmed that the target design mass flow rate and pressure ratio have been successfully achieved in the first build with a design point efficiency higher than that possible from the conventional design. Tests have demonstrated that the compressor has the required surge margin at design and off design speeds to ensure satisfactory operation when transferred to the multistage compressor environment.

Development Approach to the Dry Low Emission Combustion System of MAN Diesel and Turbo Gas Turbines

2014 ◽  
Author(s):  
Holger Huitenga ◽  
Eric R. Norster
Keyword(s):  
High Pressure ◽  
Gas Turbines ◽  
Field Tests ◽  
Test Facility ◽  
Design Parameters ◽  
Combustion System ◽  
Low Emission ◽  
Lean Premixed ◽  
Industrial Gas Turbines ◽  
Gas Pumping

The THM series of industrial gas turbines covers a power range of 6 to 12.5 MW and has been improved and uprated over many years. The majority of turbines installed are still in commercial operation and they are mainly used for compressor drives but also find generator applications. In recent years the constraints of emission legislations for new and existing gas turbines has made a development programme for a dry low emission (DLE) combustion system essential. The combustion system apart from meeting latest emission targets of 75 mg/mN3 NOx and 100 mg/mN3 CO must be suitable for both, new and retrofit engine options and therefore compact for standard enclosure installation. In addition the design should be simple and robust with the same accessibility as the existing standard combustion system. The paper describes the design and development steps to provide a prototype lean premixed DLE combustion system. The basic approach for a simple lean premixed design together with aero-thermodynamic sizing for pressure loss, flow proportions, stability and cooling is described. The initial efforts were directed to a system for the 11 MW THM 1304-11AP machine, with combustor atmospheric testing to verify design parameters and operating limits. The development was continued by subsequent high pressure testing of the prototype, starting with suitable units in the MAN engine test facility, omitting any high pressure rig tests. Field tests were carried out on a compressor drive application on a gas pumping station to prove long term durability. Adaptations of the design are now engine-tested for other THM models, even recuperated ones. Also, the combustor technology and methods developed here provide the basis for the combustors on the new MAN MGT 6100 and 6200 engines [1].

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