A new aerodynamic design system developed by authors for draft fan with enhanced efficiency

suppressed noise

enlarged flux and high load.The new design system features:A twist regulation for vortex control is employed in designing to lessen the secondary flow loss in the blade tip and hub;The feasibility and high efficiency of this procedure has been verified by the tests of the prototype fan;A new computer-aided 3D blading is used to optimize the blade;Numerical inverse checking is adopted to enhance accuracy in designing and cut down the period of the designing and production.This design system can make the optimized blade with 'forward inclination '

'inclining sweep '

'bending sweep '

to minimize the various secondary flow losses

to expand the steady working range of the fan

and to suppress the aerodynamic noise source.