Patent attributes
A propeller fan may strongly draw the flow toward the inner circumferential side and greatly improve the pressure efficiency by degrading the tendency of the flow near the pressure surface to be inclined toward the outer circumferential side at the trailing edge of the blade. The blade is provided with a recessed portion raised toward a suction surface at a central portion of a trailing edge of the blade in a radial direction such that the recessed portion is open at least on a pressure surface of the blade, the recessed portion extending from the trailing edge toward a leading edge of the blade, and a cross section of the recessed portion taken in a radial direction is provided with a pair of lateral portions rising at a predetermined angle with respect to the suction surface and facing each other. The span-wise width of the recessed portion between the lateral portions increases as the recessed portion extends from an upstream side to a downstream side.