The paper considers three operational modes of a nozzle-ejector jet system. The study suggests modeling gas-liquid injection as gas permeation through a suspension of liquid droplets in forward flow. In this case, the process will be analogous to gas flow through a fluidized bed. The research determines a pressure drop through the well-known Ergun equation, which is applicable over a wide range of Reynolds numbers. The authors identify the depth of gas-liquid layer formation during phase inversion based on theoretical studies. For the jet apparatus most frequently used in gas-liquid ejector reactors. The authors calculated the ejector length at which phase inversion occurs.