We need to use an gas ejector to blend two gasses in a precise mixture ratio. Can that be done?
Nothing could be easier. Since the motive flow goes through a sonic choke in the ejector nozzle, the motive flow is held absolutely constant if motive pressure is constant (use a pressure regulator.) If suction inlet pressure is also fixed (such as atmospheric at 14.7 psia), placing a Fox sonic choke on the suction port of the ejector will establish a fixed suction flow rate. Since both flows are fixed, mixture ratio is established. This scheme has no turndown.
