Experimental investigation to combination of simultaneous adjustment to inlet guide vanes and diffuser

The performance of the centrifugal compressor at different diffuser stagger angles and different inlet guide vane (IGV) prewhirl angles are measured. The investigation shows the performance gets quite insensitive to the prewhirl angle of IGV as the stagger angle of diffuser vane is reduced to the minimum 7°; the combination of these two stators enables to greatly improve the compressor efficiency over the entire operating rage, the maximum efficiency with the combined adjustment reaches 86.0%, higher than that in alone adjustment of IGV or diffuser vanes by 2%. The potential efficiency can be exploited via freely selectable mode of matched adjustment.