A Low-Speed Compressor Test Rig for Flutter Investigations

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Leonie Malzacher ◽  
Silvio Geist ◽  
Valentina Motta ◽  
Dieter Peitsch ◽  
Holger Hennings
Keyword(s):  
Experimental Tests ◽  
Test Facility ◽  
Test Rig ◽  
Compressor Blades ◽  
Low Speed ◽  
Surface Pressure Distribution ◽  
Wide Range ◽  
Oil Flow ◽  
Aero Engines ◽  
Set Up

A test facility for aeroeolastic investigations has been set up at the chair of Aero Engines at the Technische Universität Berlin. The test rig provides data for tool and code validation, and is used for basic aeroelastic experiments. It is a low-speed wind tunnel, which allows free and controlled flutter testing. The test section contains a linear cascade with eleven compressor blades. Nine of them are elastically suspended. The paper presents a detailed description of the test facility results to evaluate the overall flow quality alongside an aeroelastic model to predict the flutter velocity and critical interblade phase angles (IBPAs). Furthermore, chordwise pressure distributions, measured with traveling wave (TW) mode experimental tests, are presented. These measurements have been carried out for a wide range of IBPAs and have been compared to numerical results. Hot-wire anemometry has been applied to examine the inlet flow for several Mach numbers and Reynolds numbers. The results show small turbulence intensities. The blade surface pressure distribution and the flow field of the blade's suction and pressure sides have been obtained by oil flow visualization.

A Low Speed Compressor Test Rig for Flutter Investigations

2016 ◽  
Author(s):  
Leonie Malzacher ◽  
Silvio Geist ◽  
Dieter Peitsch ◽  
Holger Hennings
Keyword(s):  
Test Facility ◽  
Test Rig ◽  
Compressor Blades ◽  
Low Speed ◽  
Surface Pressure Distribution ◽  
Oil Flow ◽  
Oil Flow Visualization ◽  
Aero Engines ◽  
Flutter Testing ◽  
Phase Angles

A test facility for aereolastic investigations has been installed at the chair of Aero Engines at the Technische Universität Berlin. The test rig provides data for tool and code validation and is used for basic aeroelastic experiments. It is a low speed wind tunnel which allows free and controlled flutter testing. The test section contains a linear cascade with eleven compressor blades. Nine of them are elastically suspended. The paper presents a detailed description of the test facility, results to evaluate the overall flow quality and an aeroelastic model to predict the flutter velocity and critical interblade phase angles. Hot-wire anemometry has been applied to examine the inlet flow for several Mach- and Reynolds numbers. The results show small turbulence intensities. The blade surface pressure distribution and the flow field of the blade’s suction and pressure side has been accessed by oil flow visualization.

scholarly journals Investigations on Oil Flow Rates Projected on the Casing Walls by Splashed Lubricated Gears

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
G. Leprince ◽  
C. Changenet ◽  
F. Ville ◽  
P. Velex
Keyword(s):  
Spur Gear ◽  
Operating Conditions ◽  
Test Rig ◽  
Variable Size ◽  
Flow Measurements ◽  
Flow Rates ◽  
Lubricant Flow ◽  
Wide Range ◽  
Oil Flow ◽  
Set Up

In order to investigate the oil projected by gears rotating in an oil bath, a test rig has been set up in which the quantity of lubricant splashed at several locations on the casing walls can be measured. An oblong-shaped window of variable size is connected to a tank for flow measurements, and the system can be placed at several locations. A series of formulae have been deduced using dimensional analysis which can predict the lubricant flow rate generated by one spur gear or one disk at various places on the casing. These results have been experimentally validated over a wide range of operating conditions (rotational speed, geometry, immersion depth, etc.).

Combustion Emission Measurements With Preheated Jet Fuel

2011 ◽  
Author(s):  
Qing-ping Zheng ◽  
Sangsig Yun ◽  
Dan Titirica ◽  
Sam Sampath ◽  
Ibrahim Yimer
Keyword(s):  
Temperature Effect ◽  
Experimental Tests ◽  
Jet Fuel ◽  
Operating Conditions ◽  
Cycle Performance ◽  
Fuel Temperature ◽  
Test Rig ◽  
Temperature Regimes ◽  
Aero Engines ◽  
Set Up

Jet fuel thermal stability at high temperature is receiving increased attention recently as advanced aero engines are being pushed to high power, high pressure and temperature regimes for improved engine cycle performance and low emissions. This paper describes the rig experimental tests to assess the high fuel temperature effect on combustor emissions. A special test rig facility has been designed and set up for emission measurements with preheated fuel. The purpose of the tests is to evaluate the combustor emission characteristics under nominal and elevated fuel temperatures. The scope of the project is two fold: (1) to design, procure and establish a dedicated hot fuel deoxygenation, fuel preheat facility that can reach temperature up to 600 °F (589 K); (2) to measure combustion emissions, mainly NOx, CO and UHC, at normal and elevated fuel temperature under representative engine operating conditions. The test rig has run for extended duration and proved reliable over the whole test campaign. Measured emission results show that fuel temperature effect on NOx, CO, UHC emissions are marginal, possibly due to the low emission capability of the sector combustor that is less sensitive to fuel inlet condition changes than other combustor designs. These results indicate a manageable risk for engine development with elevated fuel temperature from the emission viewpoint.

Experimental and Numerical Flutter Investigation of the 1st Stage Rotor in 4-Stage High Speed Compressor

2008 ◽  
Author(s):  
E. Johann ◽  
B. Mu¨ck ◽  
J. Nipkau
Keyword(s):  
High Speed ◽  
Dynamic Pressure ◽  
Experimental Tests ◽  
Rotor Blades ◽  
Test Facility ◽  
Nodal Diameter ◽  
Pressure Transducers ◽  
Multistage Compressor ◽  
Set Up ◽  
Forced Responses

Experimental tests were performed to investigate flutter behaviour of the transonic rotor in a high-speed multistage compressor test facility. Besides the acquisition of overall performance parameters the rig was equipped with special instrumentation such as strain gauges, tip-timing system and dynamic pressure transducers. The 4-stage compressor comprises 3 variable vanes. The instrumentation was able to measure stall and flutter and forced responses of the rotor blades. The experimental data was used to validate the in-house aeroelastic solver. During testing flutter was triggered intentionally at part speed conditions with malscheduled variable vanes. The malschedule changed the flow incidences for the relevant rotor and induced flutter. An aeroelastic simulation was set up according to the flutter conditions found during the experiment. The measured boundary conditions were used to set up the aeroelastic simulation. The calculation shows the torsion mode with a negative aerodynamic damping which confirms the test results. The only difference between test and prediction is the nodal diameter, at which the flutter occurs.

Detection of Separation Bubbles by Infrared Images in Transonic Turbine Cascades

1988 ◽  
Vol 110 (4) ◽  
pp. 504-511 ◽  
Author(s):  
W. Bra¨unling ◽  
A. Quast ◽  
H.-J. Dietrichs
Keyword(s):  
Boundary Layer ◽  
Pressure Distribution ◽  
Infrared Image ◽  
Turbine Rotor ◽  
Test Facility ◽  
Infrared Images ◽  
Wide Range ◽  
Separation Bubbles ◽  
Oil Flow ◽  
High Pressure Stage

In a test facility for straight cascades, equipped with profiles designed for a highly loaded gas turbine rotor of a high-pressure stage, experiments were conducted to clarify some effects of shock wave–boundary layer interactions. The specific aim was to determine both the position and strength of compression shocks originating from profile wake flows and the position and extent of separation bubbles. The latter are most often detected by visualization methods like surface oil flow patterns or Schlieren photographs, as well as by typical properties in wall pressure distribution curves. In addition, the infrared image technique, which has found many applications in a wide range of technical activities in the recent years, may also be used. Compared with other methods, this technique has distinct advantages in fluid mechanics applications. The whole model can be observed without disturbing the boundary layer by tappings, measuring materials, or probes. Some typical infrared images are presented and interpreted using results of pressure distribution measurements, hot-film measurements, and surface oil flow visualizations.

An LP Turbine at Extreme Off-Design Operation

2013 ◽  
Author(s):  
Martin Lipfert ◽  
Martin Marx ◽  
Martin G. Rose ◽  
Stephan Staudacher ◽  
Inga Mahle ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Flow Field ◽  
Three Dimensional ◽  
Leading Edge ◽  
Test Facility ◽  
Second Stage ◽  
Wide Range ◽  
High Incidence ◽  
Aero Engines ◽  
Lp Turbine

In a cooperative project between the Institute of Aircraft Propulsion Systems (ILA) and MTU Aero Engines GmbH a two-stage low pressure turbine with integrated 3D airfoil and endwall contouring is tested. The experimental data taken in the altitude test-facility study the effect of high incidence in off-design operation. Steady measurements are covering a wide range of Reynolds numbers between 40,000 and 180,000. The results are compared with steady multistage CFD predictions with a focus on the stator rows. A first unsteady simulation is taken into account as well. The CFD simulations include leakage flow paths with disc cavities modeled. Compared to design operation the extreme off-design high-incidence conditions lead to a different flow-field Reynolds number sensitivity. Airfoil lift data reveals changing incidence with Reynolds number of the second stage. Increased leading edge loading of the second vane indicates a strong cross channel pressure gradient in the second stage leading to larger secondary flow regions and a more three-dimensional flow field. Global characteristics and area traverse data of the second vane are discussed. The unsteady CFD approach indicates improvement in the numerical prediction of the predominating flow field.

Experiments on a Large Flexure Pivot Journal Bearing: Summary of Test Results and Comparison With Predictions

2019 ◽  
Author(s):  
Giuseppe Vannini ◽  
Filippo Cangioli ◽  
Enrico Ciulli ◽  
Matteo Nuti ◽  
Paola Forte ◽  
...  
Keyword(s):  
High Speed ◽  
Maximum Load ◽  
Numerical Code ◽  
Test Facility ◽  
Temperature Management ◽  
Unit Load ◽  
Rolling Element ◽  
Oil Flow ◽  
Set Up ◽  
The University

Abstract Flexure Pivot® Journal Bearings (FPJBs) have typically been used in small high-speed applications such as Integrally Geared Compressors (IGCs) and multistage high-speed compressors, where the temperature management and the rotordynamic stability of the machine are the main targets. Nevertheless, the need for high-speed applications may also be applicable to large compressors and for this reason a large 280mm diameter four-pad FPJB with L/D = 0.7 has been designed, built and tested by the Authors. The test facility is a novel rig, set up at the University of Pisa, that includes a floating test bearing and a rigid rotor supported by two stiff rolling element bearings. Both static and dynamic loads are applied through hydraulic actuators, capable of 270kN static and 40kN overall dynamic load. The instrumentation can measure all the relevant test boundary conditions as well as the static and dynamic quantities that characterize the bearing performance. This paper presents the results from a test campaign conceived to explore not only the design conditions (7000rpm rotational speed and 0.75MPa unit load) but also the sensitivity to the unit load (from 0.2MPa minimum load up to 2.2MPa maximum load) as well as the oil flow. The results are discussed and compared with predictions from an existing numerical code.

The Influence of Blade Lean on Straight and Annular Turbine Cascade Flow Field

2008 ◽  
Author(s):  
Gabriele D’Ippolito ◽  
Vincenzo Dossena ◽  
Alessandro Mora
Keyword(s):  
Sensitivity Analysis ◽  
Flow Field ◽  
Experimental Tests ◽  
Phenomenological Approach ◽  
Pressure Probe ◽  
Steam Turbines ◽  
Flow Angle ◽  
Oil Flow ◽  
Lean Angle ◽  
Set Up

The paper proposes a detailed description of the flow field throughout leaned turbine nozzles and reports a sensitivity analysis with respect to the lean angle. A phenomenological approach focuses the attention on pressure contours distribution both inside and outside the passage. The study involves both straight and annular cascades mounting a typical intermediate reaction degree section, designed for steam turbines. Blades are built by stacking the same 2-D profile along different linear axis, characterized by different angles with respect to the normal or radial direction: α = 0 deg for prismatic blade and α = 10, 15 and 20 deg for the leaned ones are considered. Experimental and numerical tests were performed at the nominal inlet flow angle in order to avoid any effect related to blade sweep. Experimental tests were carried out at the design outlet Mach number of 0.65; measurements were performed at the Laboratorio di Fluidodinamica delle Macchine (LFM) of Politecnico di Milano. Only linear cascades with prismatic and 20 deg leaned blades were experimentally tested providing data both downstream and inside the blade passage by means of pressure probe traversing, endwall pressure taps and oil flow visualization. Experimental results were also used to validate the numerical set-up, which provided a detailed computational picture of the flow field throughout the channel. The influence of pressure contours shape on secondary vorticity activity downstream of the passage is highlighted and discussed, focusing the attention on secondary structures and loss distribution in this region. The resulting description of the flow field, based on the representation of pressure contours, supports the sensitivity analysis with respect to the blade lean angle, identifying the mechanism that leads the secondary vorticity to grow in regions where secondary losses and blade loading decrease.

scholarly journals Measurement Errors and Uncertainty Estimation of an Experimental Set Up Using a 2D PIV Technique

2019 ◽  
Author(s):  
Flávia V. Barbosa ◽  
Carlos A. P. Costa ◽  
Senhorinha F. C. F. Teixeira ◽  
José C. F. Teixeira
Keyword(s):  
Heat Transfer ◽  
Uncertainty Quantification ◽  
Measurement Errors ◽  
Velocity Fields ◽  
Test Facility ◽  
Air Jet ◽  
Piv Technique ◽  
High Heat Transfer ◽  
Wide Range ◽  
Set Up

Abstract The study of the flow interaction and the heat transfer between air jets and a surface is of paramount importance in industrial processes that apply multiple air jet impingement. To ensure a good performance of the process, high heat transfer rates and uniformization of the flow over the target plate are required. To perform this analysis, a PIV technique was implemented for the measurement of the velocity fields of the flow. However, as any real experiment, the values recorded by the PIV method are subjected to several errors that compromise the reliability and accuracy of the measurements. These errors can have different sources, from the installation and alignment to the particles seeding and calibration procedure. To determine an interval that contains the measurement error, the uncertainty quantification is crucial. In that sense, this paper focus on the identification of measurement errors and uncertainty quantification of an experimental set up specially built for the analysis of the interaction between a non-isothermal jets and non-flat surfaces moving perpendicularly to the jet axis. To ensure the reliability of the results, preliminary tests were performed to guarantee a uniform and stable flow and to determine the range and conditions of operation. In addition, this work presents an analysis of the system, and the source of errors are identified, quantified and, when possible, corrected. The particle seeding, which consists of olive oil droplets, is characterized and its efficiency for the flow tracking is analysed. The test facility was tested to fully characterize the flow field in terms of mean velocity profile and turbulence intensity over a wide range of Reynolds numbers and temperature. Several velocity fields are then measured until convergence of the flow quantities is reached. The combination of these measurements with high spatial resolution and low measurement errors allow to obtain accurate and precise measurement values.

Settlers or Movers? The Temporality of Past Migrations, Political Inaction and its Consequences, 1945–1985

2018 ◽  
Author(s):  
Jozefien De Bock
Keyword(s):  
Temporary Workers ◽  
Guest Workers ◽  
Temporary Migration ◽  
Wide Range ◽  
Settler Societies ◽  
Future Policy ◽  
Set Up ◽  
Legal Frameworks ◽  
Temporary Migrants ◽  
Multicultural Policies

Historically, those societies that have the longest tradition in multicultural policies are settler societies. The question of how to deal with temporary migrants has only recently aroused their interest. In Europe, temporary migration programmes have a much longer history. In the period after WWII, a wide range of legal frameworks were set up to import temporary workers, who came to be known as guest workers. In the end, many of these ‘guests’ settled in Europe permanently. Their presence lay at the basis of European multicultural policies. However, when these policies were drafted, the former mobility of guest workers had been forgotten. This chapter will focus on this mobility of initially temporary workers, comparing the period of economic growth 1945-1974 with the years after the 1974 economic crisis. Further, it will look at the kind of policies that were developed towards guest workers in the era before multiculturalism. This way, it shows how their consideration as temporary residents had far-reaching consequences for the immigrants, their descendants and the receiving societies involved. The chapter will finish by suggesting a number of lessons from the past. If the mobility-gap between guest workers and present-day migrants is not as big as generally assumed, then the consequences of previous neglect should serve as a warning for future policy making.

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