Mixed convection under high pressure

Department Fluid Systems

Konvektionszelle

Fig. 1: Convection cell in the high pressure wind tunnel Göttingen (HDG)

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PIV im HDG

Fig. 2: Flow field measured with Particle Image Velocimetry in a mixed convection cell in the high pressure wind tunnel. Colored visualization of the velocity magnitude field and superimposed velocity vectors are shown.

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The superposition of forced and free convection is called mixed convection. Depending on the ratio of buoyancy and inertia forces as well as  other characteristic parameters the possible flow regimes reach from the steady two dimensional to the turbulent chaotic state. In order to analyze the wide range of possible flow conditions a convection cell was developed which allows for applying Particle Image Velocimetry (PIV) and the heat transfer measurements to mixed convection in air under high pressure conditions in the High Pressure Wind Tunnel Göttingen (HDG). The HDG can be operated in a pressure range from 1 up to 100 bar.

With these measurements it is possible to observe the dynamics of coherent structures in mixed convection and their influence on the heat transfer. Another aim is to verify a patented method of scaling mixed convection, which allows for studying large scale mixed convection at reduced model size by adjusting the pressure and the characteristic velocity.


Contact
Andreas Westhoff
German Aerospace Center

Institute of Aerodynamics and Flow Technology
, Fluid Systems
Tel: +49 551 709-2294

Fax: +49 551 709-2241

E-Mail: Andreas.Westhoff@dlr.de
Dr.rer.nat. Johannes Bosbach
German Aerospace Center

Institute of Aerodynamics and Flow Technology
, Fluid Systems
Tel: +49 551 709-2455

Fax: +49 551 709-2241

E-Mail: Johannes.Bosbach@dlr.de
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