Supersonic ejector

Abstract

The invention discloses a supersonic ejector. The supersonic ejector comprises a gas inlet pressure chamber, a nozzle with injector, a supersonic diffusion section and a shell cylinder, the nozzle with injector is formed through connecting multiple stages of Laval nozzles with a tail nozzle in series through a mixing chamber after connecting the multiple stages of Laval nozzles in series through the mixing chamber, a forward gas inlet groove is opened in the peripheral wall of the expansion part of each Laval nozzle, the front end of the nozzle with injector is connected with the gas inlet pressure chamber, the outlet of the tail nozzle at the rear end is sleeved in the supersonic diffusion section, and the gas inlet pressure chamber, nozzle with injector and supersonic diffusion section are fixed in the shell cylinder in a mode that the central axes are the same with the central axis of the shell cylinder. The supersonic ejector fully uses the air pressure energy, the gas expands and compresses stage by stage, the mixing is complete, and the efficiency is high; the supersonic ejector uses a central symmetry structure, the manufacturing and processing are easy to perform, and the cost is low.

Description

technical field [0001] The invention relates to a supersonic ejector, in particular to a central nozzle supersonic ejector with supersonic nozzles connected in series and staged air intake, which belongs to the field of aerodynamics. Background technique [0002] Supersonic ejectors are widely used in vacuuming and increasing the total pressure of the ejected gas. Specifically, the ejected air flow with high pressure is ejected from the nozzle at a high speed and enters the mixing chamber. , Under the action of diffusion, the surrounding fluid with low pressure is entrained, the two fluids are mixed in the mixing chamber, and the momentum is exchanged. During the flow process, the speed difference decreases and becomes uniform. And the application of chemical lasers is mature. [0003] The ejector is mainly composed of ejector nozzle, mixing chamber, diffuser and so on. Commonly used nozzle forms include central nozzles, annular nozzles, and multi-point distributed nozzles...

AI Technical Summary

Problems solved by technology

[0006] In the existing ejector device, the nozzles for accelerating the ejected airflow are all Laval nozzles, and the layout forms are central nozzles, annular nozzles, and distributed multi-nozzles. It goes out to the mixing chamber and is mixed with the ejected airflow. Under a certain operating pressure, it can exert its high efficiency, but it is very difficult to debug to achieve the best performance. For example, the FD-07 wind tunnel of CAAA currently in operation, in order to match different The main flow of the wind tunnel, the ejector has been running in a non-critical state, the efficiency is very low

In some occasions, the pressure of the air source is high, and the annular nozzle or single-stage nozzle is used. The ejected airflow has no time to expand, and becomes a shock wave train in the pipeline, which becomes an interference loss.

In some occasions, in order to cooperate with the start-up and operation of the ejector, the high-pressure air source is depressurized and used, which wastes pressure energy. For example, the FD-03 wind tunnel ejector is to depressurize the 11.0MPa high-pressure air source to 3.0MPa use

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