Ejector and ejector refrigeration cycle

An ejector to be used in a vapor compression refrigeration cycle device, the ejector comprising:

• a body that includes a decompression space adapted to decompress a refrigerant flowing in from an outside of the body, a suction passage communicating with a downstream side of a refrigerant flow of the decompression space and adapted to circulate a refrigerant drawn from the outside of the body, and a pressurizing space that mixes injection refrigerant injected from the decompression space with suction refrigerant drawn from the suction passage;
• and
• a passage formation member, at least a part of which is disposed within the decompression space and the pressurizing space, the passage formation member being formed in a conical shape having a sectional area which is enlarged as it extends farther away from the decompression space, wherein
• a refrigerant passage is defined between an inner peripheral surface of a part forming the decompression space and an outer peripheral surface of the passage formation member in the body, wherein the refrigerant passage is a nozzle passage serving as a nozzle that decompresses and injects the refrigerant flowing out of a swirl space,
• a refrigerant passage is defined between an inner peripheral surface of a part forming the pressurizing space and an outer peripheral surface of the passage formation member in the body, wherein the refrigerant passage is a diffuser passage serving as a pressurizing portion that mixes the injection refrigerant with the suction refrigerant and pressurizes the mixed refrigerant,
• the body includes a bypass passage that guides the refrigerant on a side of the suction passage to a downstream side of the diffuser passage while bypassing the diffuser passage, and
• the bypass passage includes an enlarged portion that has a passage sectional area in enlarged in a refrigerant flow direction in the bypass passage, and
• the bypass passage further includes a bypass flow-rate adjustment valve that adjusts a bypass flow rate of the refrigerant circulating through the bypass passage.