Investigating the Influence of the Inlet Bypass Recirculation System on the Compressor Performance

In the present study, an experimental method is proposed to study the influence of different slot widths, ‎positions and structures of the compressor recirculation systems on the compressor performance. ‎Obtained results indicate that the compressor flow range increases with the width of the recirculation slot ‎at the expense of a narrower high-efficiency operating region. It is found that when the slot width is set to ‎‎۳ mm, the surge and choke margins are about ۱۲% higher than that of the ۲ mm slot. Moreover, it is ‎found that when the position of the recirculation slot falls in the middle area of the guide wheel and far ‎from the splitter blades, a larger surge margin can be achieved then it near the splitter blade. Adopting the ‎recirculation structure without intake retaining ring structure can effectively broaden the compressor flow ‎range. Compared with a straight slot intake structure, the compressor with an inclined slot intake structure ‎has a greater surge margin in the high-speed region; however, the high-efficiency range of the latter ‎scheme is smaller. Furthermore, the efficiency circle moves towards higher mass flow conditions. The ‎present parametric study is expected to provide a guideline to design recirculation devices‎‎.

Keywords:

Inlet bypass recirculation , Compressor design , Compressor performance