Transonic Cascade Wind Tunnel

Striae picture of an transonic compressor cascade at M1= 1.25

View of the test section of the cascade wind tunnel

This test facility is used for fundamental analysis of turbomachine profiles and for the study of specific flow phenomenon. Its test section has a variable width of 168 mm x 150-330 mm and allows inflow Mach numbers up to M1 = 1.4 with a very stable operating performance particularly at sonic speed (M1 = 1.0).
The wind tunnel is set up in a closed loop, which allows varying the Reynolds number independently of the Mach number by controlling the total pressure and the total temperature..
The central air supply system of the DLR consists of several centrifugal compressors, which can be connected in parallel or in series. Therefore the wind tunnel is extraordinary flexible

The large suction capacities of the system are unique. They enable controlling the side wall boundary layer in front of the cascade test section, the upper and lower bypass channels as well as operating the transonic upper end wall.
The suction system is also used for controlling the side wall boundary layers within the cascade passage and for suppressing secondary flow.

The great advantages of the analysis of two-dimensional cascades reach from cheap models with relatively large dimensions, easy measurement and optical accessibility, but particularly to the possibility of controlling the aerodynamical and the geometrical parameters independently of each other, which is not possible in real turbomachines.

The test facility is used for the following kind of studies:

Experimental validation of 2D and 3D numerical flow simulations with very detailed data (reference literature ASME JT July 2002)
Development and verification of new profile design concepts (reference literature ASME JT July 2000, Part 1, Part 2)
Fundamental investigation of flow phenomenon in turbomachines, e.g. boundary layer development on the profiles (transition and separation), passive and active separation control, shock boundary layer interaction
Development and control of secondary flow and corner separation. Analysing the effects of different side wall contouring concepts or profile alignments, as for example sweep or lean.

Further information:

Aerodynamical basics

Technische Daten:

Characteristically parameters:

Mach number	M1 = 0.2 - 1.4
Reynolds number	Re = 1x105 – 3.5x106
Turbulence	Tu = 1- 4%
Total pressure	pt = 0.1 – 1.8 bar
Total temperature	Tt = 300 –325 K
Test facility height	150 –330mm
Profile span width	168 mm
Inflow angle	80 – 160°

Air supply system:

Continuously operating in a closed loop
Side wall boundary layer suction
Transonic test facility for M1 = 0.9 – 1.2
Half symmetric supersonic nozzle
Silica gel dryer for transonic tests
Large suction capacity

Flow visualisation system:

Striation optic
Oil streak pattern
Liquid crystals
Light-section

Testing methods:

Static pressure distribution
Three and five hole probes
Laser two-focus anemometer

Cross-section of the transonic cascade wind tunnel cologne

Contact

Sebastian Grund
German Aerospace Center
Institute of Propulsion Technology, Fan und Verdichter
Köln
Tel.: +49 2203 601-2280

Dr.-Ing. Alexander Hergt
German Aerospace Center
Institute of Propulsion Technology, Fan und Verdichter
Köln
Tel.: +49 2203601-2217
Fax: +49 30 310006-39

Anwendungsprofile

Solid-State Physics

Aerodynamic