Ejector for refrigeration cycle device

An ejector for a vapor compression refrigeration cycle device, comprising:

• a body including a refrigerant inlet port through which a refrigerant is introduced from the vapor compression refrigeration cycle device, a swirling space in which the refrigerant flowing from the refrigerant inlet port is swirled, a depressurizing space in which the refrigerant flowing out of the swirling space is depressurized, a suction passage that communicates with a downstream side of the depressurizing space in a refrigerant flow and draws a refrigerant from an external, and a pressurizing space into which an ejection refrigerant ejected from the depressurizing space and a suction refrigerant drawn through the suction passage flow;
• and
• a passage formation member that is disposed at least in an interior of the depressurizing space and in an interior of the pressurizing space and has a conical shape increasing in cross-sectional area with distance from the depressurizing space, wherein
• the depressurizing space has a nozzle passage, which functions as a nozzle that depressurizes and ejects the refrigerant that has flowed out of the swirling space, between an inner peripheral surface of the body and an outer peripheral surface of the passage formation member,
• the pressurizing space has a diffuser passage, which functions as a diffuser that converts a kinetic energy of a mixed refrigerant of the ejection refrigerant and the suction refrigerant into a pressure energy, between the inner peripheral surface of the body and the outer peripheral surface of the passage formation member,
• in a cross-section parallel to an axial direction of the passage formation member, the outer peripheral surface of the passage formation member that defines the nozzle passage has a curved surface, and a distance from a center axis of the passage formation member to the curved surface of the passage formation member gradually increases toward the downstream side in the refrigerant flow,
• in the cross-section parallel to the axial direction, the inner peripheral surface of the body that defines the nozzle passage has a curved surface, and a distance from the center axis of the passage formation member to the curved surface of the body gradually increases toward the downstream side in the refrigerant flow,
• the curved surface of the passage formation member has a contact portion that contacts the body in the nozzle passage when the passage formation member is displaced in the axial direction, in the cross-section parallel to the axial direction of the passage formation member,
• in the cross-section parallel to the axial direction, an acute angle between a tangent at the contact portion and the center axis is defined as θ2,
• the curved surface of the passage formation member has a nozzle outlet portion that defines an outlet of the nozzle passage in the cross-section parallel to the axial direction,
• in the cross-section parallel to the axial direction, an acute angle between a tangent at the nozzle outlet portion and the center axis is defined as θ3,
• a rate of the increase of the distance from the center axis to the curved surface of the passage formation member gradually reduces toward the downstream side from the contact portion to the nozzle outlet portion in the refrigerant flow such that the angle θ2 and the angle θ3 satisfy a condition:
• θ2≥θ3, and
• a rate of the increase of the distance from the center axis to the curved surface of the body gradually reduces toward the downstream side from the contact portion to the nozzle outlet portion in the refrigerant flow.