The jet swirl gas distributor is mainly composed of Venturi nozzle and spray ring. The structure model and flow model are shown in the following figure: when the compressed air with the pressure of PP injected into the fermentation tank is ejected from the contraction nozzle, the static pressure energy is converted into the velocity energy, and the pressure at the suction port of the ejector is reduced to P1. Under the effect of the compressed air injection, the fermentation broth VL with the density of R1 is inhaled and enters the diffuser of the ejector together with the air, The gas-liquid two-phase mixing developed from initial mixing to intense mixing oscillation, and produced gas dynamic foaming and pressure foaming, which made fermentation broth and air be crushed into a large number of micro particles, creating a highly turbulent, expanding and constantly updated surface emulsion interface between gas and liquid.