Heat source unit and refrigeration cycle device

TLDR: In this article, a heat source unit is provided with an axial flow fan and a bell mouth surrounding the outer periphery of the axial fan, which is viewed in a cross-section taken in a direction parallel to the flow of air, where θ 0 is the angle formed by "line L1", which is parallel to axial direction of the fan at the position of the outer peripheral edge of the suction section where the diameter is largest.

Abstract: This heat source unit is provided with an axial flow fan and a bell mouth surrounding the outer periphery of the axial flow fan. The bell mouth comprises a cylindrical straight pipe section, a suction section which is upstream of the straight pipe section and tapered expanding toward the upstream side, and a blowout section which is downstream of the straight pipe section and tapered expanding toward the downstream side. The suction section has at least one angle-reduction section that satisfies the formula θ0 > θi > 0 when the suction section of the bell mouth is viewed in a cross section taken in a direction parallel to the flow of air, where θ0 is the angle formed by "line L1, which is parallel to the axial direction of the axial flow fan at the position of the outer peripheral edge of the suction section where the diameter is largest," and "line L2, which is perpendicular to the axial direction of the axial flow fan in the connecting area between the suction section and the straight pipe section," and θi is the angle formed by "line L2" and "line L3, which connects the intersection P between line L1 and line L2 and a position of the outer peripheral edge of the suction section where the diameter is smaller than the largest diameter but larger than the smallest diameter."