Ejector

An ejector applied to a vapor-compression refrigeration cycle device, the ejector comprising:

• an ejector body including an inflow space configured to allow a refrigerant in a liquid phase to flow thereinto, a pressure reducing space configured to reduce a pressure of the refrigerant that has flowed out of the inflow space, a suction passage communicating with a downstream side of the pressure reducing space in a refrigerant flow and allowing the refrigerant suctioned from a refrigerant suction port to flow therethrough, and a pressurizing space configured to introduce therein a jet refrigerant jetted from the pressure reducing space and a suction refrigerant drawn through the suction passage;
• and
• a valve body at least partially disposed and displaceable inside the pressure reducing space, the valve body and the ejector body defining a refrigerant passage therebetween
• wherein
• the refrigerant passage includes a nozzle passage defined between an inner peripheral surface of the ejector body defining the pressure reducing space and an outer peripheral surface of the valve body, and the nozzle passage functions as a nozzle which reduces the pressure of the refrigerant and jets the refrigerant,
• the valve body is coupled to an upstream actuating bar that extends toward the inflow space and is slidably supported by the ejector body,
• a central axis of the upstream actuating bar and a central axis of the valve body are disposed coaxially with each other,
• a plurality of throat portions formed on the inner peripheral surface of the ejector body and the outer peripheral surface of the valve body defining the nozzle passage and configured to gradually reduce the passage cross-sectional area of the nozzle passage in a downstream direction of the refrigerant flow and then turn the flow direction of the refrigerant,
• a most upstream throat portion, which is one disposed on a most upstream side in the refrigerant flow among the plurality of throat portions, is formed on the valve body, and
• the most upstream throat portion is formed in a shape that causes the flow direction of the refrigerant in the nozzle passage to turn toward the central axis of the valve body, and disposed in a region of the nozzle passage where the refrigerant flows at subsonic speed.