There has been deep interest by research workers in the metrology scope of sonic
nozzle as measuring devices in certain engineering systems (e.g. calibration of gas
flow meters, compressor discharge capacity testing and calibration of turbine
engine gas passage). The main emphasis has been on how to enhance the accurate
measurement of mass flow rate from such devices. Sonic nozzle one obvious
solution in this case. Due to simple structure, high accuracy and stable
performance.This paper gives an over view of up-to-date published research in the
performance and characteristics of sonic nozzles used for calibrating gas flow
meters. Some articles were reviewed and examined, covering various aspects of the
subject, including the main illustrations and prominent results. The reviewed
articles include those concentrating either on experimental, on numerical
simulation, on theoretical investigation, or on combination. From discussion of
articles there exist a great dependence on body temperature and geometry of sonic
nozzle to get more accuratemeasurements .Beside that the back pressure effects on
mass flow rate and normal shock in sonic nozzles used in calibration facilities
should have more interest of study.Also there is still some room for further work,
such as development the effect of geometry and kind of gases on discharge
coefficient with deeper insight, to be carried out.