AC Axial Fan design principles

(1) "AC Axial Fan" asymmetrical outer boundary (including asymmetric impeller gap) is a cross flow fan can produce a stable fluid flow in a direction along the basic conditions.
(2) When the "AC Axial Fan" fluid driven rotary impeller, if the flow field is only a straight line boundary in the vicinity of the boundary of this, the downstream direction of the impeller rotation at the minimum clearance, the inner edge of the impeller to form a vortex. Cross flow fan direction of rotation of the vortex impeller turning the same vortex strength depends largely on the speed of the impeller and boundary conditions. Flow field resulting vortex impeller inside and outside the main control.
(3) If more than one boundary, the flow field depends on the combined effects of the various borders. Vortex appears in the difference between the maximum flow resistance in the vicinity of the border, and only one of the
(4) For the "AC Axial Fan", to make the anti-fade operation without air, as compared with other boundaries cut out, at the vortex of the tongue should have a large difference in flow resistance.