Abstract: A counter-rotating fan which comprises a forward-skewed upstream rotor and a backskewed downstream rotor. The counter-rotating fan may be used in a cooling module with a heat exchanger, for example as an engine cooling fan in a vehicle.

Abstract: Stationary flow control vanes positioned to encounter and redirect recirculating airflow provide a surprising combination of efficiency, low noise, and manufacturability for shrouded, banded, axial fans that are positioned in a housing. Such fan and housing combinations reduce swirl in recirculating airflow, so that the airflow entering the fan (which includes the recirculating airflow) is more ordered and fan performance is improved. The invention is particularly suited for fans that draw airflow through an upstream heat exchanger. It can also be applied to fans that blow air through a downstream heat exchanger. The invention is also suited for ducted fans.

Abstract: An improvement to forwardly skewed axial fans whereby blade camber and rake are coordinated with skew. The blades are characterized in that a line defined by the points of maximum chordwise camber (f.sub.max) as a function of changing radial position (r) is on the leading edge side of the mid-chord line (M.sub.CL) at values of r toward the root of the blade, and is less forwardly skewed than the leading edge (LE), the mid-chord line (M.sub.CL), and the trailing edge (TE) of said blade; the blade is raked forwardly so that the trailing edge of the blade tip is axially forward of the trailing edge at the blade root; rake (k) increases monotonically as radial position r increases from 0.75R to 1.0R, R being the fan radius; the blade has a relatively large pitch ratio (P/D); and rake is corrected to reflect the chordwise position of maximum camber.