Turbomachinery Experimental

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LEC’s cutting edge turbomachinery research has a direct and profound impact on reducing environmental impact in the fields of power generation and mobility.

Heat transfer measurements in an axial turbine with endwall contouring and 3D blading.

Research Facilities

LEC houses unique facilities that are without equal in most universities and research laboratories. The unique facilities of LEC enable complex experimental and computational projects to be locally performed, over the shortest possible period, with high quality. The experimental facilities in LEC are designed to simulate and test new concepts at full-scale nondimensionals. Advanced test equipment, dedicated test benches, fully automated, data acquisition, processing and storage ensure the quality and timeliness of all test data. A brief description of the available unique facilities is provided below, and more details can be found in the related publications.

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Multi-stage Axial Turbine Research Facility (LISA)

LEC’s cutting edge turbomachinery research has a direct and profound impact on reducing environmental impact in the fields of power generation and mobility.

LISA is a state-of-the-art axial research turbine facility engineered and assembled at LEC. Ongoing research in LISA is aimed at finding the best trade-off between aerodynamic efficiency, thermal management and mechanical design. LISA is a quasi–closed type turbine facility, whose generated turbine power is fed back into the electrical grid through a generator. The facility is driven by a radial compressor, and a two-stage water-to-air heat exchanger is used to precisely control the flow temperature; a calibrated venturi nozzle accurately measures the mass flow. LISA can accommodate turbines with up to two stages, having two individual shafts for each stage and independent measurement of each stage’s power. The facility is designed to accommodate a broad range of measurement techniques, with emphasis on unsteady flow measurement techniques. LISA offers both multiple probe access at the exit of blade rows for unsteady data acquisition, as well as capability for inter-stator measurements. Both FRAP and FENT are applied in LISA. More recently, unsteady wall pressures in cavities and on the turbine blades have been integrated with specifically designed data acquisition systems in order to identify non-synchronous cavity modes and in order to determine the blade forcing. Moreover optical access enables measurements techniques such as PIV to be used.

High-Speed Centrifugal Compressor Rig (Rigi)

Impeller aerodynamics, system instabilities and the application of on-impeller measurement techniques are amongst the research topics that have been conducted in the high-speed centrifugal compressor test rig, Rigi. Currently, the primary research focus in the facility is the investigation of forced response of radial compressors.

Rigi consists of a single stage centrifugal compressor system that is operated in a closed loop; this arrangement allows the inlet pressure, temperature and working fluid to be adjusted independently of ambient conditions. The working fluid can be varied from pure air to an air/CO2 mixture, in order to change the speed of sound of the working fluid. A flow straightener, mounted in the suction pipe, ensures axial flow at the stage inlet. Downstream of the compression stage, the fluid is cooled and then discharged through a throttle prior to re-entering the impeller.

Since the whole stage area is easy to access the rig can be equipped with a variety of measurement systems. The performance is monitored in terms of total pressure ratio by also making use of a venturi nozzle for mass flow measurements.

Detailed pressure measurements in the suction pipe, along the shroud and in the diffuser section of the stage can be made to characterize compressor instabilities. A fully automated 3-axis traversing system with access to the inlet of the rig and with access to the diffuser section provides detailed flow field measurements using pneumatic probes or in-house developed fast response aerodynamic probes.

The impeller can be equipped with strain gauges in order to measure vibratory response of the blades and it can be equipped with fast response pressure sensors, which allow to determine the aerodynamic forcing and damping.


Subsonic wind tunnel powered by centrifugal compressor (Laval)

The Laval test rig consists of a subsonic wind tunnel powered by a centrifugal compressor. In the current configuration, the wind tunnel has been adapted primarily for film cooling experiments. The freestream flow can be heated by a steam heat exchanger which can be accurately regulated and controlled. The boundary layer thickness of the flow is controlled by a suction arrangement. In order to study mixing and jet impingement a secondary air supply provides air which can be cryogenically cooled. This cooled air can be injected through different hole arrangements to study various jet-in-crossflow configurations. The different temperatures between the injectant and the freestream are required to simulate the density ratios typically found in jet engines. In order to study unsteady effects the cool air can also be pulsated via an in-house designed pulsator.

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Sun Jun 25 09:04:32 CEST 2017
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