Numerical simulation and characteristic comparison of sonic nozzle

As the main standard flowmeter, Sonic nozzle has been widely used in aerospace, petrochemical and biomedical fields. Recently, a number of studies have been conducted on small-scale sonic nozzles. Since the standard ISO sonic nozzle is difficult to process at a small scale, the geometry of the shrink nozzle, the diffusion nozzle and the conical venturi nozzle is proposed based on the circular ISO nozzle, and the geometric structure and shape flow to the nozzle. A preliminary analysis of the effects of the characteristics was carried out. In this paper, the computational fluid dynamics method is used to numerically simulate the flow field inside the three sonic nozzles. The influence of the geometry of the constricted section, the throat and the diffusing section on the nozzle flow characteristics is analyzed and compared with the annular ISO nozzle. In contrast, the flow characteristics of four kinds of microsonic nozzles are compared. Considering the feasibility of actual processing, the geometric structure with better discharge coefficient and critical back pressure ratio is obtained, which provides a reference for the development of micro nozzles.