Rotating flows

Department Fluid Systems

 
Zentrifuge

Fig. 1: Colored isolines of the mean temperature distribution in a cross section of the centrifuges bowl computed with CFD for a speed of n = 30 000 rpm  and pressures of  p = 0.3 bar (left) and p = 1.013 bar (right).

Windkraftanlage mit Stromlinien
Fig. 2: Colored isolines of the vorticity magnitude and streamlines of the flow around a NREL phase VI wind turbine.

Rotating flows are found in many technical applications. In medical technologies the centrifugal forces generated by rotation of solid bowl centrifuges are used the separate fluid components. To prevent excessive heating of the probes due to friction at high speed, centrifuges are cooled with liquid helium. Detailed investigations of the heating of the centrifuges interior and the involved flow mechanism are conducted with Computational Fluid Mechanics (CFD). Computed temperature distribution within the centrifuge for two pressures are presented in Fig. 1. Besides rotating flows are also found for ventilators, fans and wind turbines. In these systems the mechanical torque is based on the aerodynamic lift generated at the rotor blades in sometimes turbulent and hence strongly fluctuating flows. To optimize rotors for such conditions they are optimized for example based on the results of CFD-computations of the flow around a wind turbine illustrated in Fig. 2.


Contact
Dr.-Ing.habil. Mykhailo Konstantynov
German Aerospace Center

Institute of Aerodynamics and Flow Technology
, Fluid Systems
Tel: +49 551 709-2876

Fax: +49 551 709-2241

E-Mail: Mikhail.Konstantinov@dlr.de
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