摘要
In order to understand the breakup performance of coaxial porous injectors,the sprays of coaxial porous injectors with two different porous material cylinder lengths were compared with those of conventional shear coaxial injectors.To allow comparison,the wall injection lengths were designed to be equivalent to the value of the recess depth.Cold flow sprays were visualized using back-lit photography methods and analyzed quantitatively with a laser diffraction apparatus,in order to study the effects of the momentum flux ratio and Weber number on the breakup for each type of injector.In case of the shear coaxial injector,the large liquid core was observed in low air mass flow rate condition.However,the destabilization of the liquid jet from the coaxial porous injector is almost complete within the inner region,near the injector face plate.Additionally,better breakup performance in low gas flow rate condition was obtained when the porous cylinder length decreased,while the shear coaxial injectors showed better breakup efficiency when the recess length increased.In conclusion,the different breakup process caused by the radial momentum in the inner region of the porous injector disintegrated the liquid core.
In order to understand the breakup performance of coaxial porous injectors,the sprays of coaxial porous injectors with two different porous material cylinder lengths were compared with those of conventional shear coaxial injectors.To allow comparison,the wall injection lengths were designed to be equivalent to the value of the recess depth.Cold flow sprays were visualized using back-lit photography methods and analyzed quantitatively with a laser diffraction apparatus,in order to study the effects of the momentum flux ratio and Weber number on the breakup for each type of injector.In case of the shear coaxial injector,the large liquid core was observed in low air mass flow rate condition.However,the destabilization of the liquid jet from the coaxial porous injector is almost complete within the inner region,near the injector face plate.Additionally,better breakup performance in low gas flow rate condition was obtained when the porous cylinder length decreased,while the shear coaxial injectors showed better breakup efficiency when the recess length increased.In conclusion,the different breakup process caused by the radial momentum in the inner region of the porous injector disintegrated the liquid core.
基金
supported by a National Research Foundation of Korea(NRF)grant funded by the Korean Government(Ministry of Science,ICT and Future Planning)(No.NRF-2012M 1A3A3A02033146 and NRF-2013RlA5A1073861 through the SPRC of Seoul National University)
