A study of the performance of a radial diffuser for a multistage high-pressure pump

In this study, a high-pressure multistage pump used in combined cycle power plants is analyzed. The pump performance characteristics (differential head and efficiency) are numerically analyzed for different shapes of the radial diffuser. The design variables selected for the radial diffuser are number of vanes, diameter ratio (D₄/D₃), return channel outlet angel (α₆), and pressure recovery factor (C_p). The numerical analysis results showed that the differential head and efficiency are the highest when the diameter ratio is the highest. Further, it was observed that the differential head was lower when the return channel outlet angle was 60° than when it was 90°, because of preswirl at the diffuser outlet.