Research Papers: Gas Turbines: Structures and Dynamics

A Remotely Operated Aeroelastically Unstable Low Pressure Turbine Cascade for Turbomachinery Aeromechanics Education and Training—Remote Flutter Lab

[+] Author and Article Information
Monaco Lucio

Heat and Power Technology,
KTH Royal Institute of Technology,
Stockholm SE-100 44, Sweden
e-mail: lucio@kth.se

John Bergmans

Bergmans Mechatronics LLC,
Newport Beach, CA 92660
e-mail: jbergmans@bergmans.com

Damian Vogt

University of Stuttgart,
Stuttgart 70569, Germany
e-mail: damian.vogt@itsm.uni-stuttgart.de

Torsten H. Fransson

Heat and Power Technology,
KTH Royal Institute of Technology,
Stockholm SE-100 44, Sweden
e-mail: torsten.fransson@energy.kth.se

More than 800 remote students from African countries and Sri Lanka have been enrolled in the two-year remote M.Sc. programs run by HPT.

Erasmus Mundus (2009–2013) is a worldwide cooperation and mobility programme in higher education sponsored and coordinated by the European Commission (http://eacea.ec.europa.eu/erasmus_mundus). Through Action 1, the programme supports in a highly competitive way a limited number of joint programmes at the M.Sc. and Ph.D. level.

The axis is placed such that the torsion mode investigated corresponds to a two-dimensional rotation about the center of mass of the blade. Repositioning of the axis is not possible in the present setup.

Estimated frequencies of oscillation of the blades are less than 100 Hz.

Novotechnik P2501A502.

The channels, of diameter 1.2 mm (1.0 mm for the channel closest to the trailing edge), are designed in a through-going way in the spanwise direction (for easier cleaning after printing of the blade) and are later filled with two-component epoxy until the location of the pressure tappings.

Honeywell SSCDRRN100MDAA5. Dynamic calibration of the recess-mounted transducers is done according to the technique described in Ref. [10].

LabView 2010 SP1 Professional Development System.

LabSocket v2.5.9.

Intervention of a technician is of course required in the event of system failure. Its occurrence and consequences are however mitigated by a number of hardware and software solutions that allow for continuous monitoring of the remote operation (e.g., sending automatic emails to the lab responsible when someone takes control of the rig, shutting down the fan in case of prolonged absence of user input or in case of software crash), that take corrective actions in case of operating conditions that might harm the integrity of the equipment (such as prolonged permanence in vibrating conditions of the blades).

Statistics are not yet available. Statement based on experience from previous remote labs at HPT.

A demo of the exercise structure and material is available at www.energy.kth.se/proj/projects/Remote_labs/RL/RL_website/RFL/RFL.html. Times are estimated for students enrolled in the thermal turbomachinery course at KTH. Total estimated time: 6 h.

The users select themselves the team and as such teams are created with members from anywhere in the world.

The video is filmed with 3D camcorder in the side-by-side 3D format and then converted to the mp4 format such that it can also be watched in 2D if the learner does not have access to 3D technology.

A future scenario with learners answering in real-time to the questions of the “virtual” trainer and vice versa is under study.

Different off-design cases are presently assigned according to the time reserved for the lab and of the number of groups in the course.

Moodle supports federated and open social authentication.

Calculation exercises of this type are already implemented in Bilda and used regularly in courses at HPT such as in the turbomachinery and thermal turbomachinery courses.

Contributed by the Structures and Dynamics Committee of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received July 13, 2014; final manuscript received August 11, 2014; published online October 7, 2014. Editor: David Wisler.

J. Eng. Gas Turbines Power 137(3), 032507 (Oct 07, 2014) (8 pages) Paper No: GTP-14-1382; doi: 10.1115/1.4028463 History: Received July 13, 2014; Revised August 11, 2014

The use of advanced pedagogical methodologies in connection with advanced use of modern information technology for delivery enables new ways of communicating, of exchanging knowledge, and of learning that are gaining increasing relevance in our society. Remote laboratory exercises offer the possibility to enhance learning for students in different technical areas, especially to the ones not having physical access to laboratory facilities and thus spreading knowledge in a world-wide perspective. A new “Remote Flutter Laboratory” has been developed to introduce aeromechanics engineering students and professionals to aeroelastic phenomena in turbomachinery. The laboratory is world-wide unique in the sense that it allows global access for learners anywhere and anytime to a facility dedicated to what is both a complex and relevant area for gas turbine design and operation. The core of the system consists of an aeroelastically unstable turbine blade row that exhibits self-excited and self-sustained flutter at specific operating conditions. Steady and unsteady blade loading and motion data are simultaneously acquired on five neighboring suspended blades and the whole system allows for a distant-based operation and monitoring of the rig as well as for automatic data retrieval. This paper focuses on the development of the Remote Flutter Laboratory exercise as a hands-on learning platform for online and distant-based education and training in turbomachinery aeromechanics enabling familiarization with the concept of critical reduced frequency and of flutter phenomena. This laboratory setup can easily be used “as is” directly by any turbomachinery teacher in the world, free of charge and independent upon time and location with the intended learning outcomes as specified in the lab, but it can also very easily be adapted to other intended learning outcomes that a teacher might want to highlight in a specific course. As such it is also a base for a turbomachinery repository of advanced remote laboratories of global uniqueness and access. The present work documents also the pioneer implementation of the LabSocket System for the remote operation of a wind tunnel test facility from any Internet-enabled computer, tablet or smartphone with no end-user software or plug-in installation.

Copyright © 2015 by ASME
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Fig. 1

Integration of remote labs in existing courses at KTH

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Fig. 2

(a) Linear cascade test rig and (b) modular design concept of the rig with interchangeable modules (FLM physically installed in the rig configuration shown in the photo)

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Fig. 3

RFL flutter lab module

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Fig. 4

(a) Elastically suspended blade and (b) position of pressure tappings at the midspan section

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Fig. 5

GUI for the control and monitoring of the test rig. Browser access from smartphone.

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Fig. 6

Access to the network cameras from smartphone via (a) web browser and (b) free app (different camera views shown)

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Fig. 7

Activities included in the remote laboratory exercise and corresponding estimated time required per student

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Fig. 8

Dynamic visualization of CAD model in (a) 3D Adobe Acrobat documents and (b) free app GrabCAD

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Fig. 9

Side-by-side 2D view of the 3D video briefing

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Fig. 10

Stiffness and natural frequency versus free-length of the springs, average values over the five instrumented blades

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Fig. 11

Indexing of blades in the cascade (left) and steady blade loading (right)

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Fig. 12

Time-resolved data from the instrumented blades. Blade displacement refers to the amplitude of rotation about the predefined torsion axis, pressure signal is from pressure tap PS3 (data include correction from unsteady calibration).




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