The invention relates to a pneumatic design method for an ultrahigh-load, ultralow-rotating-speed and large-bypass-ratio fan rotor, and belongs to the technical field of
impeller machinery. The pneumatic design method includes the steps that firstly, key design parameters are determined through S2 through-flow analysis according to flow and the
overall pressure ratio, and the load coefficient is selected between 0.7 and 1.0; secondly, a plurality of S1
stream surface two-dimensional blade forms (7) are designed according to the inlet and outlet
parameter distribution, determined according to S2 through-flow analysis, of the rotor; thirdly, the two-dimensional blade forms designed in the second step are stacked in the radial direction to form three-dimensional blades (11), and the fan rotor (12) is formed according to the number of selected blades; and fourthly, the performance curve of a fan is obtained by conducting three-dimensional flow
field simulation of the fan rotor (12) through
computer simulation or conducting performance tests through experiments, whether design reaches the standard and meets the requirement or not is tested, and improved design is conducted. By means of the pneumatic design method for the ultrahigh-load, ultralow-rotating-speed and large-bypass-ratio fan rotor, on the premise of ensuring the pneumatic performance of the fan,
noise and the weight of the fan are effectively reduced.