The Cryogenic Wind Tunnel Cologne (KKK)

The Cryogenic Wind Tunnel Cologne (KKK) is a closed circuit low speed tunnel. To achieve high Reynolds numbers, the gas temperature in the tunnel circuit can be lowered down to 100 K by injecting liquid nitrogen. The Reynolds number can be thus increased by a factor of 5.5 while the drive power remains Key Technical Parameters constant (see Figure 2). Due to the possibility of Test section: 2.4 m x 2.4 m x 5.4 m Stagnation pressure: atmospheric independent variation of the gas temperature Fan power: 1.4 MW Dynamic pressure (max): 1.1 x 104 Pa and flow velocity, the influence...

The Cryogenic Wind Tunnel Cologne (KKK) The lock and the model conditioning room both have individual temperature control systems provided by nitrogen and dry air injection and high Reynolds-numbers enforced heating. In this manner they can also be used as independent cryogenic (pre-)test facilities. Test Capabilities and Measurement Techniques Due to its Reynolds-Mach capability the KKK is an outstanding wind tunnel for high lift low speed take-off and landing configuration testing of all kind of aircraft as well as for fast ground vehicles like high speed trains. For this there are three different...

with Vortex Generators Ma - 0.2 Internal six-component balances and a five-component half model strain gauge balance are used for force measurements and a temperature compensated electronic pressure scanning system (PSI) for pressure measurements. For surface flow visualization the CO2-sublimation method, colored oil, mini-tufts, and infrared imaging can be used. Flow field data can be acquired by pitot and five-hole probe rakes on a traversing mechanism and by a particle image velocimetry system (PIV, obtainable from DLR). For transition detection infrared imaging and temperature sensitive paint...

Half model simulation technique is widely used is considerably increased and thus the behavior of stall controlled wind rotors is affected. Figure 6 Wing tip vorticity distribution-five- Half Model Testing hole probe rake results. To examine trim conditions and high lift systems of aircraft configurations in symmetric flow, the half model simulation technique is widely used. This reduces model costs and permits a larger scale with the benefits of better detailing and a higher Reynolds number. The effectiveness of control setting and design can be studied by high precision measurement of differences...

The Cryogenic Wind Tunnel Cologne (KKK) (not heated) internal strain gauge balances are Figure 9 available to be used in the complete temperature range 100 K < T < 300 K (see Figure 9). The actual angle of attack is controlled by an internal heated internal six-component inclinometer. All measurement techniques used in strain gauge balance. airfoil and half model tests, e.g. surface and wake pressure probes, flow visualization, and PIV can be applied in full model testing as well. The lift curves and drag polars of a fighter configuration shown in Figure 10 were measured in the KKK. The findings...

The cryo-technique, in contradiction to pressurized tunnels, has the advantage of not raising the pressure load on the model high speed train. They are recorded at a tunnel temperature of 100K and Mach number of 0.2. The model in the upper picture is clean, while the High speed train model on the half model in the lower picture is dimpled. The effect of dimpled surface is obvious. Cryo-Model Requirements The cryogenic environment down to 100 K requires the choice of an appropriate material. The strain due to temperature gradients should be low. The corresponding coefficients of all different...

Wind Tunnels Operated by DNW General Inquiry Henri Vos Business Development Mobile: +31 6 12 97 52 82 E-mail: [email protected] HST, SST Anthony Fokkerweg 2 1059 CM Amsterdam The Netherlands Contact: G.H. Hegen E-mail: [email protected] NWB Lilienthalplatz 7 38108 Braunschweig Germany Contact: A. Bergmann E-mail: [email protected] TWG, HDG, KRG, RWG BunsenstraGe 10 37073 Gottingen Germany Contact: K.-W. Bock E-mail: [email protected] KKK Linder Hohe 51147 Koln Germany Contact: R. Rebstock E-mail: [email protected] LLF, LST, ECF Voorsterweg 31 8316 PR Marknesse The Netherlands...