A two-stage high-loading fan with three-dimensional numerical simulations was studied. The simulation results were used to propose a scheme that enlarged the stall margin of multistage high-loading fans without sacrifice of the flow capacity when operating with a large mass flow rate. Furthermore

a circumferential groove casing treatment was used and adjustments were made to the upstream stator angle to match the casing treatment. The stall margin was thus increased to 16.3%

without reduction in the maximum mass flow rate or the design thrust performance.