Newsletter  2019.3  Index

Theme : "The Conference of Fluid Engineering Division" Preface (T. HASHIMOTO，S. MATSUDA，H.J. PARK) Development and launch of sounding rockets and development status of small launch vehicle by Japanese startup company Takahiro INAGAWA (Interstellar Technologies Inc.) Experimental quantification of friction drag reduction effects on an airfoil using uniform blowing Kaoruko ETO, Yusuke KONDO, Koji FUKAGATA (Keio University)and Naoko TOKUGAWA (Japan Aerospace Exploration Agency) Wind-tunnel experiments of friction drag reduction on an airfoil using passive blowing Shiho HIROKAWA, Kaoruko ETO, Yusuke KONDO, Koji FUKAGATA (Keio University)and Naoko  TOKUGAWA (Japan Aerospace Exploration Agency) A Study on Airfoil Flow and Aerodynamic Noise with Wake-boundary layer Interaction Noriaki KOBAYASHI　(The University of Tokyo) LES Analysis of Stator Cascade Flow in a Transonic Axial Compressor Seishiro SAITO (Kyushu University) Influence of grid resolution in large-eddy simulation of a turbulent pipe flow using the WALE model Daiki IWASA, Yusuke NABAE, Koji FUKAGATA (Keio University) The Dreams of Flow Contest Tomomi TERADA (Hokkaido University)   Separation of floating waste by "Water Surface Control Device" Toshiki HOMMA　 (Meisei University)

 

LES Analysis of Stator Cascade Flow in a Transonic Axial Compressor

Seishiro SAITO Kyushu University

Abstract

The turbulent flow field in a stator cascade of the two-stage transonic axial compressor has been investigated using a large-scale unsteady simulation including LES and DES analysis. Specifically, the LES analysis was performed only in the first stator, and the DES analysis was applied to the other blade cascades. The grid resolution in the first stator was very fine in order to resolve the turbulent flow field with the LES. The number of computational cells per blade passage is approximately 30 million in the first stator, and the total number of computational cells is about 1.2 billion. The flow field was analyzed by using the data mining techniques including the vortex identification based on the critical point theory and the limiting streamline visualization based on the line integral convolution (LIC) method. It is found that the hub-corner separation occurs in the first stator and interferes with the shock wave from the second rotor and the wake from the first rotor. Although only one hub-corner separation vortex is formed in the time-averaged flow field, the hub-corner separation vortex is generated in multiple pieces in an instantaneous flow field and those pieces fluctuate with time rapidly, distorting the near-hub flow. The shock waves from the second rotor enter the passage of the first stator and interfere with the blade surface boundary layer, so that several flow separations occur on the blade surface in the first stator.

Key words

Turbomachinery, Axial compressor, LES, Unsteady flow, Shock wave, Hub-corner separation

Figures

Fig. 1  Computational grid

Fig. 2  Time-averaged flow field in first stator

Fig. 3  Instantaneous flow field in first stator