Abstract: A centrifugal fan includes a first member coupled to a rotation shaft, a second member opposed to the first member, and a vane disposed between the first member and the second member. The vane includes a solid portion and a pressure variation reducing portion. The pressure variation reducing portion is disposed on one of a positive pressure surface and a negative pressure surface of the vane. The vane includes a leading edge disposed at a radially inward position and a trailing edge disposed at a radially outward position. The pressure variation reducing portion has an area centroid located closer to the leading edge than to the trailing edge.

Abstract: A bell mouth includes a circumferential wall, and a pressure changing component permeable portion arranged in the circumferential wall at a location where a separated distance from an axial fan is minimal. A fan unit includes the bell mouth, an axial fan, and a case that accommodates the axial fan and the bell mouth. The fan unit has an air layer between the circumferential wall of the bell mouth and the case.

Abstract: A centrifugal blower includes an impeller, and a scroll casing. The impeller draws in gas through an opening in a side surface and sends out the gas in a centrifugal direction. The scroll casing includes an inlet, an outlet, a peripheral wall arranged along an impeller outer circumference, and a tongue that guides the gas flowing along the peripheral wall to the outlet. The peripheral wall includes a first planar portion extending continuously from the tongue, and a second planar portion located at a position advanced from the first planar portion in a rotation direction of the impeller. The peripheral wall is arranged so that a clearance is minimal at the second planar portion. The clearance is a difference between distances from a center of the impeller to an inner surface of the peripheral wall and to an outer surface of the impeller in a passage along the peripheral wall.

Abstract: A bell mouth includes a circumferential wall, and a pressure changing component permeable portion arranged in the circumferential wall at a location where a separated distance from an axial fan is minimal. A fan unit includes the bell mouth, an axial fan, and a case that accommodates the axial fan and the bell mouth. The fan unit has an air layer between the circumferential wall of the bell mouth and the case.

Abstract: An axial fan includes a hub attachable to a rotary shaft, and five or less blades arranged on the hub. Each blade includes a leading edge located forward in a rotation direction of the rotary shaft, a trailing edge located rearward in the rotation direction of the rotary shaft, and a porous part. A dimension from the leading edge to the trailing edge is a blade chord length, and the porous part is arranged at a position located rearward from the leading edge by 40% or more of the blade chord length.

Abstract: A centrifugal blower includes an impeller, and a scroll casing. The impeller draws in gas through an opening in a side surface and sends out the gas in a centrifugal direction. The scroll casing includes an inlet, an outlet, a peripheral wall arranged along an impeller outer circumference, and a tongue that guides the gas flowing along the peripheral wall to the outlet. The peripheral wall includes a first planar portion extending continuously from the tongue, and a second planar portion located at a position advanced from the first planar portion in a rotation direction of the impeller. The peripheral wall is arranged so that a clearance is minimal at the second planar portion. The clearance is a difference between distances from a center of the impeller to an inner surface of the peripheral wall and to an outer surface of the impeller in a passage along the peripheral wall.

Abstract: A propeller fan includes a blade configured to rotate around a predetermined rotation axis, and a ring connected to a blade end of the blade. The blade includes a curved portion on a side on which the blade end is located. The curved portion has, in a rotational radial direction of the blade, a cross-sectional shape projecting in a convex manner toward a side on which a pressure surface is located. In the curved portion, when a height from a position of a blade root on a camber line in a direction along the predetermined rotation axis is an axial-direction height and a position at which the axial-direction height becomes maximum in the rotational radial direction is a maximum curve position, the axial-direction height at the maximum curve position is maximum on a side on which a trailing edge of the blade is located.

Abstract: A propeller fan includes a hub rotatable about an axis, and a plurality of blades extending radially outward from an outer peripheral surface of the hub. A ring surrounds the plurality of blades and is connected to each blade tip. A maximum camber location is on a camber line where a distance from a chord line to the camber line in an arc-shaped cross section of each blade about the axis is maximum. An axial height is from a trailing edge to the camber line in a direction along the axis. Each blade has a first portion provided inside in the radial direction of rotation and whose axial height at the maximum camber location is substantially constant, and a second portion provided outside in the radial direction of rotation and whose axial height at the maximum camber location increases toward the blade tip.

Abstract: A fixed blade has a chord line inclined downstream in a rotation direction of a rotor vane throughout a radial direction. An average of an installation angle on an outer peripheral side of the fixed blade from a midpoint of a straight line extending in the radial direction from an outer peripheral end of an upstream edge of the fixed blade to an outer peripheral surface of the fixed hub is less than an average of the installation angle on an inner peripheral side of the fixed blade from the midpoint of the straight line, where the installation angle is formed by the chord line of the fixed blade with respect to a plane perpendicular to an axis.

Abstract: A propeller fan includes a blade configured to rotate around a predetermined rotation axis, and a ring connected to a blade end of the blade. The blade includes a curved portion on a side on which the blade end is located. The curved portion has, in a rotational radial direction of the blade, a cross-sectional shape projecting in a convex manner toward a side on which a pressure surface is located. In the curved portion, when a height from a position of a blade root on a camber line in a direction along the predetermined rotation axis is an axial-direction height and a position at which the axial-direction height becomes maximum in the rotational radial direction is a maximum curve position, the axial-direction height at the maximum curve position is maximum on a side on which a trailing edge of the blade is located.

Abstract: A propeller fan includes a hub rotatable about an axis, and a plurality of blades extending radially outward from an outer peripheral surface of the hub. A ring surrounds the plurality of blades and is connected to each blade tip. A maximum camber location is on a camber line where a distance from a chord line to the camber line in an arc-shaped cross section of each blade about the axis is maximum. An axial height is from a trailing edge to the camber line in a direction along the axis. Each blade has a first portion provided inside in the radial direction of rotation and whose axial height at the maximum camber location is substantially constant, and a second portion provided outside in the radial direction of rotation and whose axial height at the maximum camber location increases toward the blade tip.