Performance improvement of a centrifugal compressor through redesign of two-row vaned diffuser

This study numerically evaluates the performance improvement of a centrifugal compressor by redesigning two-row vaned diffusers. It emphasizes key design factors, such as blade thickness, the use of splitter blades, and tandem diffuser configurations. The results show that optimizing the second diffuser’s thickness-to-chord ratio to 0.15 increases efficiency by 1.4%, the pressure ratio by 1.1%, and pressure recovery by 20.8%. Removing the splitter blades from the first diffuser slightly improves efficiency and significantly boosts pressure recovery. Additionally, introducing a radial gap in the main blade of the first diffuser enhances both efficiency and pressure ratio. The use of tandem diffusers shows considerable performance gains, with optimal setups determined for different operating conditions. Tandem diffusers provide a modest performance boost, improved pressure recovery, and lower weight and manufacturing costs compared to diffusers equipped with splitter blades. Overall, the findings highlight the crucial role of diffuser design in enhancing centrifugal compressor performance, leading to a 4.5% improvement in isentropic efficiency and a 21% increase in pressure recovery compared to the baseline design.