Heat source unit and refrigeration cycle apparatus

A heat source unit, comprising:

• an axial-flow fan;
• and
• a bellmouth surrounding an outer periphery of the axial-flow fan,
• wherein the bellmouth includes:
• a straight tubular portion having a cylindrical shape;
• an air inlet portion, which is positioned on an upstream side of the straight tubular portion, and is radially expanded toward the upstream side;
• and
• an air outlet portion, which is positioned on a downstream side of the straight tubular portion, and is radially expanded toward the downstream side, and
• wherein, in sectional view of the air inlet portion of the bellmouth taken along a direction parallel to flow of an air, the air inlet portion has at least one angle-reduced portion that satisfies θ0>0i>0, where, an angle formed by a line L1 and a line L2 is taken as θ0, and an angle formed by a straight line L3 and the line L2 is taken as θi, the line L1 is a line passing through a portion of an outer peripheral end portion of the air inlet portion, which has a maximum diameter, and running in parallel to an axial direction of the axial-flow fan, the line L2 is a line passing through a connecting portion between the air inlet portion and the straight tubular portion and running in a direction orthogonal to the axial direction of the axial-flow fan, and the straight line L3 is a line connecting an intersection P of the line L1 and the line L2 and a portion of the outer peripheral end portion of the air inlet portion, which has a diameter smaller than the maximum diameter and larger than a minimum diameter and
• the angle-reduced portion is formed to be linear in sectional view of the inlet portion of the bellmouth in a direction orthogonal to the flow of the air.