An experimental study on effect of Inner jet shapes on the mixing Characteristics of high speed Coaxial jets

Abstract

Advances in the aerospace propulsion field have led to the newlinedevelopment of high speed missiles aircraft and spacecraft systems newlineSupersonic jets discharged from a nozzle play a major role in these advances newlineand the accompanying applications Achieving higher combustion efficiency newlineand better exhaust conditions thorough suitable jet flows in supersonic newlinenozzles for scramjet engines and hypersonic vehicles are vital One way in newlineattaining the right flow is the usage of coaxial jets to provide mixing of fluids newlineA coaxial stream I e secondary stream is imparted into a primary supersonic newlinejet through a coaxial annular nozzle The supersonic jet is discharged from the newlineinner nozzle and the secondary stream from outer annular nozzle A properly newlinedesigned jet will efficiently mix air and fuel while providing the best overall newlinecombustion parameters Especially the performance characteristics of newlinepropulsion systems such as efficiency and pollutant formation depend on the newlineappropriate selection of operating conditions Moreover the mixing and newlineentrainment of the compressible shear layers in highly reacting turbulent newlineflows requires a vigilant investigation newlineResearches on simple jet flow pattern have been nearly exhaustive Yet supersonic non circular coaxial jets have not been focused Besides in all newlinethe above mentioned studies combinations of subsonic and turbulent jet flow newlinehave not been dealt with As a result this research aims to quantify the effects newlineof the geometry of the primary supersonic jet on the mixing characteristics newlinewith the secondary high speed subsonic jet newlineThe effect of nozzle shapes such as circle rectangle triangle on the newlinemixing characteristics of supersonic flow such as spreading rate potential newlinecore length jet half width Mach number decay etc are studied Jet shape newlinearea ratio and total pressure at the nozzle inlet of inner jets and jet speed newline