scholarly journals Commissioning of a Combined Hot-Streak and Swirl Profile Generator in a Transonic Turbine Test Facility

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
Maxwell G. Adams ◽  
Thomas Povey ◽  
Benjamin F. Hall ◽  
David N. Cardwell ◽  
Kam S. Chana ◽  
...  
Keyword(s):  
Boundary Condition ◽  
Reynolds Number ◽  
Gas Turbines ◽  
Test Facility ◽  
Lean Burn ◽  
Numerical Predictions ◽  
Turbine Inlet ◽  
Total Temperature ◽  
Inlet Conditions ◽  
Inlet Boundary Condition

Abstract By enhancing the premixing of fuel and air prior to combustion, recently developed lean-burn combustor systems have led to reduced NOx and particulate emissions in gas turbines. Lean-burn combustor exit flows are typically characterized by nonuniformities in total temperature, or so-called hot-streaks, swirling velocity profiles, and high turbulence intensity. While these systems improve combustor performance, the exiting flow-field presents significant challenges to the aerothermal performance of the downstream turbine. This paper presents the commissioning of a new fully annular lean-burn combustor simulator for use in the Oxford Turbine Research Facility (OTRF), a transonic rotating facility capable of matching nondimensional engine conditions. The combustor simulator can deliver engine-representative turbine inlet conditions featuring swirl and hot-streaks either separately or simultaneously. To the best of our knowledge, this simulator is the first of its kind to be implemented in a rotating turbine test facility.The combustor simulator was experimentally commissioned in two stages. The first stage of commissioning experiments was conducted using a bespoke facility exhausting to atmospheric conditions (Hall and Povey, 2015, “Experimental Study of Non-Reacting Low NOx Combustor Simulator for Scaled Turbine Experiments,” ASME Paper No. GT2015-43530.) and included area surveys of the generated temperature and swirl profiles. The survey data confirmed that the simulator performed as designed, reproducing the key features of a lean-burn combustor. However, due to the hot and cold air mixing process occurring at lower Reynolds number in the facility, there was uncertainty concerning the degree to which the measured temperature profile represented that in OTRF. The second stage of commissioning experiments was conducted with the simulator installed in the OTRF. Measurements of the total temperature field at turbine inlet and of the high-pressure (HP) nozzle guide vane (NGV) loading distributions were obtained and compared to measurements with uniform inlet conditions. The experimental survey results were compared to unsteady numerical predictions of the simulator at both atmospheric and OTRF conditions. A high level of agreement was demonstrated, indicating that the Reynolds number effects associated with the change to OTRF conditions were small. Finally, data from the atmospheric test facility and the OTRF were combined with the numerical predictions to provide an inlet boundary condition for numerical simulation of the test turbine stage. The NGV loading measurements show good agreement with the numerical predictions, providing validation of the stage inlet boundary condition imposed. The successful commissioning of the simulator in the OTRF will enable future experimental studies of lean-burn combustor–turbine interaction.

Investigation of Combustor-Turbine-Interaction in a Rotating Cooled Transonic High-Pressure Turbine Test Rig: Part 2 — Numerical Modelling and Simulation

2019 ◽  
Author(s):  
Simon Gövert ◽  
Federica Ferraro ◽  
Alexander Krumme ◽  
Clemens Buske ◽  
Marc Tegeler ◽  
...  
Keyword(s):  
High Pressure ◽  
Flame Stabilization ◽  
Test Facility ◽  
Test Rig ◽  
High Pressure Turbine ◽  
Lean Burn ◽  
Turbine Inlet ◽  
Measurement Results ◽  
Aero Engine ◽  
Inlet Conditions

Abstract Reducing the uncertainties in the prediction of turbine inlet conditions is a crucial aspect to improve aero engine designs and further increase engine efficiencies. To meet constantly stricter emission regulations, lean burn combustion could play a key role for future engine designs. However, these combustion systems are characterized by significant swirl for flame stabilization and reduced cooling air mass flows. As a result, substantial spatial and transient variations of the turbine inlet conditions are encountered. To investigate the effect of the combustor on the high pressure turbine, a rotating cooled transonic high-pressure configuration has been designed and investigated experimentally at the DLR turbine test facility ‘NG-Turb’ in Göttingen, Germany. It is a rotating full annular 1.5 stage turbine configuration which is coupled to a combustor simulator. The combustor simulator is designed to create turbine inlet conditions which are hydrodynamically representative for a lean-burn aero engine. A detailed description of the test rig and its instrumentation as well as a discussion of the measurement results is presented in part I of this paper. Part II focuses on numerical modeling of the test rig to further extend the understanding of the measurement results. Integrated simulations of the configuration including combustor simulator and nozzle guide vanes are performed for leading edge and passage clocking position and the effect on the hot streak migration is discussed. The simulation and experimental results at the combustor-turbine interface are compared showing a good overall agreement. The relevant flow features are correctly predicted in the simulations, proving the suitability of the numerical model for application to integrated combustor-turbine interaction analysis.

Effects of Non-Uniform Combustor Exit Flow on Turbine Aerodynamics

2012 ◽  
Author(s):  
Stavros Pyliouras ◽  
Heinz-Peter Schiffer ◽  
Erik Janke ◽  
Lars Willer
Keyword(s):  
Boundary Condition ◽  
Test Rig ◽  
Lean Burn ◽  
Lean Combustion ◽  
Flow Mechanisms ◽  
Low Nox Combustion ◽  
Inhomogeneous Temperature ◽  
The Impact ◽  
Inlet Boundary Condition ◽  
Insight Into

Very-low NOx combustion concepts require a high swirl number of the flow in the combustion chamber to allow for lean burn combustion. This article deals with the influence of the resulting combustor exit swirl on the turbine aerodynamics of the first stage. This investigation is based on numerical simulations. According to the literature research additional insight into combustor-turbine interaction is achieved by taking into account a fully two dimensional inlet boundary condition. Up to now published results on combustor-turbine interaction were mostly restricted to the inhomogeneous temperature distribution at the turbine inlet. The investigations are carried out on a real engine geometry — the E3E Core 3/2 — a research project of Rolls-Royce Deutschland on lean combustion. Calculations are conducted by means of the Rolls-Royce plc code Hydra. The swirled inlet boundary condition is further scaled to test rig conditions to check for the transferability between the test rig and the real engine geometry. The results show a significant impact of the inhomogeneous turbine inflow on the stage efficiency and the thermal load. The optimization potential due to the clocking position of the combustor swirl is analyzed. The impact on the secondary flow mechanisms is analyzed with a novel visualization technique. A frequency spectrum analysis is carried out to investigate the effects of the 2D inlet boundary condition on the rotor row.

scholarly journals A Unique Small Gas Turbine Test Facility for Low-Cost Investigations of Ceramic Rotor Materials and Thermal Barrier Coatings

1998 ◽  
Author(s):  
Björn Schenk ◽  
Torsten Eggert ◽  
Helmut Pucher
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Low Cost ◽  
Temperature Gradients ◽  
Test Facility ◽  
Small Scale ◽  
Transient Temperature ◽  
Turbine Inlet ◽  
Turbine Rotors

The paper describes a test facility for small-scale gas turbines, which basically has been designed and assembled at the Institute of Combustion Engines of the Technical University Berlin. The facility exposes ceramic rotor components to the most significant loads that occur during real gas turbine operation in a clearly predefined manner (high circumferential velocities and highest turbine inlet temperatures). The test facility allows the investigation of bladed radial inflow turbine rotors, as well as — in a preceding step — geometrically simplified ceramic or coated metallic rotors. A newly designed, ceramically lined, variable geometry combustion chamber allows turbine inlet temperatures up to 1450°C (2640 F). A fast thermal shock unit (switching time of about 1s), which is integrated into the test facility between the combustion chamber and the turbine scroll, can be used to create, for example, severe transient temperature gradients within the rotor components to simulate gas turbine trip conditions. In order to generate steady state temperature gradients, especially during disk testing, the rotor components can be subjected to an impingement cooling of the rotor back face (uncoated in case of TBC-testing). The test facility is additionally equipped with a non-contact transient temperature measurement system (turbine radiation pyrometry) to determine the test rotor surface temperature distribution during operation. Apart from the possibilities of basic rotor material investigations, the test facility can also be used to automatically generate compressor and turbine performance characteristics maps. The latter might be used to assess the aerodynamic performance of bladed ceramic radial inflow or mixed flow turbine rotors with respect to manufacturing tolerances due to near-net-shape forming processes (e.g., gelcasting or injection molding).

Calibration of Gas Turbine Blade Temperature Predictions Using Surrogate Models

2012 ◽  
Author(s):  
John M. McFarland ◽  
Grant O. Musgrove ◽  
Sung Yong Chang ◽  
David L. Ransom
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Thermal Analyses ◽  
Surrogate Models ◽  
Operating Conditions ◽  
Test Bed ◽  
Turbine Inlet ◽  
Speed Up ◽  
Inlet Conditions ◽  
Thickness Measurements

Actual gas turbine performance and component life at specific engine installations is highly dependent on the actual operating conditions, since not all engines are operated in the same manner. Due to the variability in turbine operation, it may be prudent to evaluate the operation of hot section components for turbine inlet conditions that are specific to a single installation. However, determining the actual turbine inlet conditions can be a difficult and expensive process that is usually only done on test bed gas turbines. This paper presents a method to determine turbine inlet conditions using a model calibration approach. Two-stage CFD and thermal analyses are developed to predict blade temperature. By varying the model inputs, computational predictions of blade temperature are calibrated to blade interdiffusion zone thickness measurements. In order to speed up calculations, surrogate models are used in place of the full-scale analysis codes during the calibration analysis. The result of the study is a prediction of the turbine inlet profile necessary to obtain the best agreement between predicted and measured blade temperatures.

Experimental Study of Automotive Aerodynamics in Headlamp Effect

2011 ◽  
Vol 279 ◽  
pp. 339-344
Author(s):  
Lan Fang Jiang ◽  
Hong Liu ◽  
Ai Qi Li
Keyword(s):  
Numerical Simulation ◽  
Boundary Condition ◽  
Experimental Study ◽  
Reynolds Number ◽  
Wind Tunnel ◽  
Drag Coefficient ◽  
Surface Pressure ◽  
Symmetry Plane ◽  
Automotive Aerodynamics ◽  
Inlet Boundary Condition

The effect of headlamp modeling on automotive aerodynamics was studied by wind tunnel tests. Firstly, the effect of Reynolds number on drag coefficient of automotive scaled down models was studied under different velocity of flow to verify the rationality of selecting scale for scaled down model and setting inlet boundary condition. Secondly, drag coefficient of automotive scaled down models with different headlamp modeling design were measured. Thirdly, the distribution of surface pressure on central symmetry plane and headlamp was measured and analyzed. It also validated the validity of preceding numerical simulation. It is of importance to guide the headlamp modeling design and automotive modeling design.

Aerodynamic Evaluation of Double Annular Combustion Systems

2002 ◽  
Author(s):  
Paul A. Denman
Keyword(s):  
Gas Turbines ◽  
Pollutant Emissions ◽  
Quality Data ◽  
Test Facility ◽  
Oxides Of Nitrogen ◽  
Combustion System ◽  
Modular Construction ◽  
Radial Depth ◽  
Annular Combustor ◽  
Inlet Conditions

Legislation controlling the permitted levels of pollutant emissions from aircraft gas turbines has been an increasingly important design driver for the combustion system for some time, particularly with respect to oxides of nitrogen. This has lead to many suggestions for radical departures from the geometry of the classical combustor configuration involving, for example, lean premixed module technology, or staging (axially or radially) of combustor pilot and main zones. The optimum operation of any combustor also requires, however, appropriate and efficient distribution of compressor delivery air to the various flametube features (fuel injectors, dilution ports, for cooling and for air bleed purposes). Radial staging, leading to double annular combustor configurations, poses a particularly difficult challenge. The radial depth of the combustor increases to a level where the external aerodynamics of the combustor involves large flow turning after the pre-diffuser. Careful design is then needed to achieve acceptable levels of loss coefficient in the outer annulus. If these aspects are not properly addressed then inadequate penetration and mixing in the combustor interior can result, rendering low emissions performance impossible. This paper will report on the design, instrumentation and operation of a fully annular isothermal test facility, which has been developed specifically to enable this important issue of external flow quality in double annular combustor systems to be assessed. Representative inlet conditions to the combustion system are generated using a single stage axial compressor; modular construction enables quick and inexpensive changes to components of the combustor (pre-diffuser, cowl shape, liner port locations and geometrical details). Computerised rig control and data acquisition allows the collection of large amounts of high quality data. In addition to the calculation of overall system performance, it is then possible to identify flow mechanisms and loss-producing features in various zones and suggest appropriate modifications.

scholarly journals Effects of a combined hot-streak and swirl profile on cooled 1.5-stage turbine aerodynamics: an experimental and computational study

2020 ◽  
pp. 1-24
Author(s):  
Maxwell G. Adams ◽  
Paul F. Beard ◽  
Mark R. Stokes ◽  
Fredrik Wallin ◽  
Kam S. Chana ◽  
...  
Keyword(s):  
Performance Studies ◽  
Gas Turbines ◽  
Computational Study ◽  
Inlet Temperature ◽  
Lean Burn ◽  
Flow Angle ◽  
Rotor Aerodynamics ◽  
Total Temperature ◽  
Hot Streak ◽  
Profile Area

Abstract Recently developed lean-burn combustors offer reduced NOx emissions for gas turbines. The flow at exit of lean-burn combustors is dominated by hot-streaks and residual swirl, which have been shown–individually–to impact turbine aerodynamic performance. Studies have shown that residual swirl at inlet to the high-pressure (HP) stage predominantly affects the vane aerodynamics, while hot-streaks affect the rotor aerodynamics. Studies have also shown that these changes to the HP stage aerodynamics can affect the downstream intermediate-pressure (IP) vane aerodynamics. Yet, to date, there have been no published studies presenting experimental turbine test data with both swirl and hot-streaks simultaneously present at inlet. This paper presents the first experimental and computational investigation into the effects of combined hot-streaks and swirl on turbine aerodynamics. Measurements were conducted in the Oxford Turbine Research Facility, a short-duration rotating transonic facility that matches non-dimensional engine conditions. Two turbine inlet flows are considered. The first is uniform in total pressure, total temperature, and flow angle. The second features a non-uniform total temperature (hot-streak) profile featuring strong radial and weak circumferential variation superimposed on a swirling velocity profile. Area surveys of the flow were conducted throughout the turbine. Measurements and URANS predictions suggest that the inlet temperature non-uniformity was relatively well preserved upon being convected through the turbine, and relatively poor comparisons between URANS and experiment highlight the challenge of accurately predicting the complex IP vane flow.

scholarly journals Sensitivity analysis of FDA´s benchmark nozzle regarding in vitro imperfections - Do we need asymmetric CFD benchmarks?

2020 ◽  
Vol 6 (3) ◽  
pp. 78-81
Author(s):  
Michael Stiehm ◽  
Christoph Brandt-Wunderlich ◽  
Stefan Siewert ◽  
Klaus-Peter Schmitz ◽  
Niels Grabow ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Flow Field ◽  
In Silico ◽  
Nozzle Geometry ◽  
Geometrical Imperfection ◽  
Custom Made ◽  
Inlet Conditions ◽  
Silicone Model ◽  
Bench Testing

AbstractModern technologies and methods such as computer simulation, so-called in silico methods, foster the development of medical devices. For accelerating the uptake of computer simulations and to increase credibility and reliability the U.S. Food and Drug Administration organized an inter-laboratory round robin study of a generic nozzle geometry. In preparation of own bench testing experiment using Particle Image Velocimetry, a custom made silicone nozzle was manufactured. By using in silico computational fluid dynamics method the influence of in vitro imperfections, such as inflow variations and geometrical deviations, on the flow field were evaluated. Based on literature the throat Reynolds number was varied Rethroat = 500 ± 50. It could be shown that the flow field errors resulted from variations of inlet conditions can be largely eliminated by normalizing if the Reynolds number is known. Furthermore, a symmetric imperfection of the silicone model within manufacturing tolerance does not affect the flow as much as an asymmetric failure such as an unintended curvature of the nozzle. In brief, we can conclude that geometrical imperfection of the reference experiment should be considered accordingly to in silico modelling. The question arises, if an asymmetric benchmark for biofluid analysis needs to be established. An eccentric nozzle benchmark could be a suitable case and will be further investigated.

The MIT Blowdown Turbine Facility

1984 ◽  
Author(s):  
A. H. Epstein ◽  
G. R. Guenette ◽  
R. J. G. Norton
Keyword(s):  
Heat Transfer ◽  
Fluid Mechanics ◽  
Short Duration ◽  
Three Dimensional ◽  
Inlet Pressure ◽  
Test Facility ◽  
Turbine Inlet ◽  
High Work

A short duration (0.4 sec) test facility, capable of testing 0.5-meter diameter, film-cooled, high work aircraft turbine stages at rigorously simulated engine conditions has been designed, constructed, and tested. The simulation capability of the facility extends up to 40 atm inlet pressure at 2500°K (4000°F) turbine inlet temperatures. The facility is intended primarily for the exploration of unsteady, three-dimensional fluid mechanics and heat transfer in modern turbine stages.

Measurements and Modeling of Ingress in a New 1.5-Stage Turbine Research Facility

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Marios Patinios ◽  
James A. Scobie ◽  
Carl M. Sangan ◽  
J. Michael Owen ◽  
Gary D. Lock
Keyword(s):  
Theoretical Model ◽  
Gas Turbines ◽  
Test Facility ◽  
Radial Clearance ◽  
Operating Life ◽  
The Core ◽  
Wide Range ◽  
Purge Flow ◽  
Rotor Disk ◽  
Engine Components

In gas turbines, hot mainstream flow can be ingested into the wheel-space formed between stator and rotor disks as a result of the circumferential pressure asymmetry in the annulus; this ingress can significantly affect the operating life, performance, and integrity of highly stressed, vulnerable engine components. Rim seals, fitted at the periphery of the disks, are used to minimize ingress and therefore reduce the amount of purge flow required to seal the wheel-space and cool the disks. This paper presents experimental results from a new 1.5-stage test facility designed to investigate ingress into the wheel-spaces upstream and downstream of a rotor disk. The fluid-dynamically scaled rig operates at incompressible flow conditions, far removed from the harsh environment of the engine which is not conducive to experimental measurements. The test facility features interchangeable rim-seal components, offering significant flexibility and expediency in terms of data collection over a wide range of sealing flow rates. The rig was specifically designed to enable an efficient method of ranking and quantifying the performance of generic and engine-specific seal geometries. The radial variation of CO2 gas concentration, pressure, and swirl is measured to explore, for the first time, the flow structure in both the upstream and downstream wheel-spaces. The measurements show that the concentration in the core is equal to that on the stator walls and that both distributions are virtually invariant with radius. These measurements confirm that mixing between ingress and egress is essentially complete immediately after the ingested fluid enters the wheel-space and that the fluid from the boundary layer on the stator is the source of that in the core. The swirl in the core is shown to determine the radial distribution of pressure in the wheel-space. The performance of a double radial-clearance seal is evaluated in terms of the variation of effectiveness with sealing flow rate for both the upstream and the downstream wheel-spaces and is found to be independent of rotational Reynolds number. A simple theoretical orifice model was fitted to the experimental data showing good agreement between theory and experiment for all cases. This observation is of great significance as it demonstrates that the theoretical model can accurately predict ingress even when it is driven by the complex unsteady pressure field in the annulus upstream and downstream of the rotor. The combination of the theoretical model and the new test rig with its flexibility and capability for detailed measurements provides a powerful tool for the engine rim-seal designer.

Sign in / Sign up

Export Citation Format

Share Document