Study on the pulsation characteristics of Roots-type hydrogen circulation pump suppressed by a twisted-blade rotor

A novel twisted-blade rotor was developed for Roots-type hydrogen circulation pumps to suppress pressure and flow pulsations while maintaining high flow efficiency. Three-dimensional unsteady simulations were conducted and validated through experiments, with results showing an error below 2%. The effects of blade twist angle on pump performance were systematically analyzed. The results show that increasing the twist angle can significantly reduce pulsation intensities and radial forces, with a moderate decrease in average flow rate and a nonmonotonic change in isentropic efficiency. At the optimal twist angle of 15°, flow rate and pressure pulsations decrease by 42.37% and 31.14%, respectively, while the isentropic efficiency improves by 0.83% compared with the straight-blade rotor. The pre-intake effect induced by the twisted blades promotes early pressure equalization in the transition chamber, reducing inter-chamber pressure differences and outlet fluctuations. This mechanism can smoothen the internal flow and reduces energy loss without changing the radial clearance. This design has an advantage in achieving simultaneous pulsation suppression and efficiency retention, providing new insights for the optimization of hydrogen circulation pumps.