Open Access3D numerical investigations of the swirling flow in a straight diffuser for the variable speed values of the rotor obtained with a magneto-rheological brake
Author(s) -
R. Szakal,
Sebastian Muntean,
AI Bosioc,
Romeo Susan-Resiga,
L. Vékás
Publication year - 2021
Publication title -
iop conference series. earth and environmental science
Language(s) - English
Resource type - Journals
eISSN - 1755-1307
pISSN - 1755-1315
DOI - 10.1088/1755-1315/774/1/012019
Subject(s) - mechanics , diffuser (optics) , rotor (electric) , physics , turbulence , vortex , flow (mathematics) , torque , optics , light source , quantum mechanics , thermodynamics
The self-induced instabilities developed in decelerated swirling flows lead to pressure fluctuations. The swirling flows generated under variable speeds of the rotor of a swirl generator using a magneto-rheological brake are numerically and experimentally investigated. Three-dimensional turbulent flow computation is performed for several rotor speeds. Two mean velocity components numerically computed are validated against LDV data on a survey axis located downstream to the rotor for two speed values. The torque on the rotor blade is examined for several speeds. The numerical results are checked against the design values to identify the benefits and limitations of the concepts applied to the design stage. The flux of moment of momentum is modified when the rotor speed is slow down. The circulation, the total pressure and the swirl free velocity are examined on a cross section located downstream to the rotor for all investigated speeds. As a result, the changes of the hydrodynamic flow field are quantified. The unsteady pressure measured on the cone wall at four levels is acquired. The Fourier spectra associated with different self-induced instabilities developed in the cone are examined revealing the distribution of both plunging and rotating components. A low frequency plunging component in a straight diffuser is determined on a speed range of the rotor.