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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2017, Vol. 38 ›› Issue (6): 120745-120745.doi: 10.7527/S1000-6893.2016.0313

• Fluid Mechanics and Flight Mechanics • Previous Articles     Next Articles

New method for predicting 3-D water droplet impingement on rotor considering influence of shadow zone

CHEN Xi, ZHAO Qijun   

  1. National Key Laboratory of Science and Technology on Rotorcraft Aeromechanics, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
  • Received:2016-09-01 Revised:2016-11-25 Online:2017-06-15 Published:2016-12-05
  • Supported by:

    National Natural Science Foundation of China (11272150)

Abstract:

For the complex 3-D viscous flowfield of the helicopter rotor, a new 3-D Eulerian method is established for calculating the droplet impingement on the rotor. The Computional Fluid Dynamics (CFD) simulation method for predicting the rotor flowfield is developed based on the embedded grid method. Considering the 3-D effect of the rotor fully, the 3-D flowfield of droplets on the same embedded grids is solved by the Eulerian method to overcome the defects of the traditional 2-D calculation method. To overcome the problem of numerical stability and convergence by the density impulse in the wake area, a shadow zone dispersion model is proposed. In the model, a shadow variable is used to control the generation and dispersion of the shadow cells. The new Eulerian method is validated by comparing the calculation and experiment results of NACA0012 airfoil and UH-1H rotor in hover. In addition, the effects of the atmospheric temperature and Median Volumetric Diameter (MVD) of the droplet on the droplet impingement on the rotor are calculated and analyzed. Results show that the computation time of the 2-D droplet impingement property is reduced by 22% and the calculation stability of 3-D droplet impingement property is improved by using the shadow zone dispersion model. The droplet impingement area increases with the spanwise distance on the rotor blade. The maximum droplet local collection efficiency presents the change tendency of ‘increase-decrease-increase’, and the variation amplitude is close to 50%. The droplet impingement area and the collection efficiency increase with the increase of the MVD.

Key words: rotor, ice accretion, water droplet impingement property, Eulerian method, shadow zone, CFD

CLC Number: