Patent ID: 7334427
Filing Date: 2008-02-26
Classification: B60H,F04F,F25B

Abstract:
1. A vapor compression refrigerant cycle comprising: a compressor for compressing refrigerant; a radiator for cooling high-pressure refrigerant discharged from the compressor; an evaporator for evaporating the refrigerant; an ejector having a nozzle for decompressing the high-pressure refrigerant from the radiator, and a housing which surrounds the nozzle to define a flow passage through which a low-pressure refrigerant from the evaporator is drawn and extends downstream of the nozzle to define a mixing portion in which a nozzle jet flow of the high-pressure refrigerant from an outlet port of the nozzle and the low-pressure refrigerant drawn are mixed, wherein: the nozzle includes the outlet port from which the nozzle jet flow is jetted, and a nozzle tapered section located at an upstream side of the outlet port, wherein the nozzle tapered section has an inner passage with a radial dimension reduced toward the outlet port; and wherein the ejector further comprises: a needle having a needle tapered section disposed in the inner passage, the needle tapered section having a cross sectional area reduced toward a downstream end of the needle; wherein the needle is supported such that the downstream end of the needle is always positioned downstream with respect to the outlet port of the nozzle between a small flow amount and a large flow amount jetted from the outlet port; and the nozzle tapered section has a taper angle (φ the flow passage defined inside the housing has an inlet angle (φ) set equal to or less than 40 degrees, and the outlet port, the nozzle tapered section, the needle tapered section and the inlet angle are set to make the nozzle jet flow expanded and boiled so that flow speed of the nozzle jet flow is increased up to the supersonic speed, and a boundary face, which is an outer periphery of the nozzle jet flow, diffused to a position where the nozzle jet flow and the low-pressure refrigerant flowing around the nozzle jet flow balance with each other.