بررسي تاثير رفتار رئولوژي پيشرانه ژل بر مشخصه هاي اتميزاسيون انژكتور جريان پيچشي

Investigation of Effect of Rheological Behavior of Gelled Propellant on Atomization Characteristics of Swirl Injector

ﭘﯿﺸﺮاﻧﻪﻫﺎي ژل ﺑﻪ ﻋﻠﺖ ﺑﺮﺧﻮرداري از ﻣﺰاﯾﺎي ﻫﺮ دو ﭘﯿﺸﺮاﻧﻪ ﺟﺎﻣﺪ و ﻣﺎﯾﻊ آﯾﻨﺪة اﻣﯿﺪ ﺑﺨﺸﯽ در ﮐﺎرﺑﺮدﻫﺎي ﻫﻮاﻓﻀﺎﯾﯽ دارﻧﺪ. ﭘﯿﺸﺮاﻧﻪﻫﺎي ژل ﭘﯿﺸﺮاﻧﻪﻫﺎي ﻣﺎﯾﻌﯽ ﻫﺴﺘﻨﺪ ﮐﻪ ﺧﻮاص رﺋﻮﻟﻮژﯾﮑﯽ آنﻫﺎ ﺑﺎ اﻓﺰودن ژلﮐﻨﻨﺪه و ﺑﺮﺧﯽ اﻓﺰودﻧﯽﻫﺎ ﺗﻐﯿﯿﺮ ﻣﯽﮐﻨﺪ. ﺧﻮاص رﺋﻮﻟﻮژﯾﮑﯽ ﭘﯿﺸﺮاﻧﻪ ﺗﺄﺛﯿﺮ زﯾﺎدي ﺑﺮ ﻓﺮآﯾﻨﺪ اﺗﻤﯿﺰاﺳﯿﻮن آن دارد، ﺑﻨﺎﺑﺮاﯾﻦ در اﯾﻦ ﻣﻘﺎﻟﻪ ﺿﻤﻦ ﻣﻌﺮﻓﯽ ﺧﻮاص رﺋﻮﻟﻮژﯾﮑﯽ ﭘﯿﺸﺮاﻧﮥ ژل، ﺑﻪ ﺗﺄﺛﯿﺮ ﺧﻮاص اﯾﻦ ﭘﯿﺸﺮاﻧﻪ ﺑﺮ اﺗﻤﯿﺰاﺳﯿﻮن در اﻧﮋﮐﺘﻮر ﺟﺮﯾﺎن ﭘﯿﭽﺸﯽ ﭘﺮداﺧﺘﻪ ﺷﺪه و ﺑﺮﺧﯽ ﻧﮑﺎت ﻣﻬﻢ ﺟﻬﺖ ﻃﺮاﺣﯽ اﻧﮋﮐﺘﻮر ﺟﺮﯾﺎن ﭘﯿﭽﺸﯽ، ﺑﻪ ﻣﻨﻈﻮر اﻓﺰاﯾﺶ ﮐﯿﻔﯿﺖ اﺗﻤﯿﺰاﺳﯿﻮن ﭘﯿﺸﺮاﻧﮥ ژﻟﯽ اراﺋﻪ ﺷﺪه اﺳﺖ. ﻧﺘﺎﯾﺞ ﺣﺎﺻﻞ از ﺑﺮرﺳﯽﻫﺎ ﻧﺸﺎن دادﻧﺪ ﮐﻪ ﺑﺎﻻ ﺑﻮدن وﯾﺴﮑﻮزﯾﺘﮥ اوﻟﯿﮥ ﭘﯿﺸﺮاﻧﮥ ژل ﻧﺴﺒﺖ ﺑﻪ ﭘﯿﺸﺮاﻧﮥ ﻣﺎﯾﻊ ﻣﺎدر ﻣﻮﺟﺐ اﻓﺰاﯾﺶ ﺿﺮﯾﺐ ﺗﺨﻠﯿﻪ، اﻧﺪازه ﻗﻄﺮ ﻗﻄﺮات و ﻃﻮل ﺷﮑﺴﺖ ﺻﻔﺤﺎت ژل و ﮐﺎﻫﺶ زاوﯾﮥ ﭘﺎﺷﺶ در اﻧﮋﮐﺘﻮر ﺟﺮﯾﺎن ﭘﯿﭽﺸﯽ ﻣﯽﺷﻮد و از ﻧﻈﺮ ﻣﯿﺰان اﺛﺮﮔﺬاري ﺑﺮ ﻋﻤﻠﮑﺮد ﺳﯿﺴﺘﻢ ﭘﯿﺸﺮاﻧﺶ ژل اﻧﺪازة ﻗﻄﺮ ﻗﻄﺮات از اﻫﻤﯿﺖ ﺑﯿﺸﺘﺮي ﺑﺮﺧﻮردار اﺳﺖ. ﻫﻤﭽﻨﯿﻦ، ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ ﺧﺎﺻﯿﺖ ﻧﺎزكﺷﻮﻧﺪﮔﯽ ﺑﺮﺷﯽ ﭘﯿﺸﺮاﻧﮥ ژل و اﻣﮑﺎن اﺗﻤﯿﺰاﺳﯿﻮن ﭘﯿﺸﺮاﻧﮥ ژل ﺑﺎ اﻧﮋﮐﺘﻮر ﺟﺮﯾﺎن ﭘﯿﭽﺸﯽ، ﺑﻪ ﻣﻨﻈﻮر ﺑﻬﺒﻮد اﺗﻤﯿﺰاﺳﯿﻮن ﭘﯿﺸﺮاﻧﮥ ژل، ﻃﺮاﺣﯽ اﻧﮋﮐﺘﻮر ﺟﺮﯾﺎن ﭘﯿﭽﺸﯽ ﺑﺎﯾﺪ ﺑﻪﮔﻮﻧﻪاي ﺑﺎﺷﺪ ﮐﻪ ﻧﺮخ ﺑﺮش ﺑﯿﺸﺘﺮي ﺑﻪ ﭘﯿﺸﺮاﻧﮥ ژل ﺟﻬﺖ ﮐﺎﻫﺶ وﯾﺴﮑﻮزﯾﺘﻪ اوﻟﯿﻪ آن اﻋﻤﺎل ﮐﻨﺪ.

The Gelled propellants have a promising future for aerospace applications because of possessing the advantages of both solid and liquid propellants. A gel propellant is a liquid propellant whose rheological properties have changed by the addition of gellant and other additives. The rheological properties of the propellant have a significant influence on the atomization process. In this paper, the rheological properties of the gel propellant are introduced. Then, the effect of gel propellant properties on the atomization in the swirl injector has been investigated. Subsequently, some important points for designing a swirl injector that can influence enhancing the atomization quality of the gelled propellant are presented. The results of the studies revealed that higher initial viscosity of the gelled propellant compared with the mother liquid propellant cause increase in the discharge coefficient, the size of droplet diameter, and the breakup length of the gel sheet while causing a decrease of spray cone angle in the swirl injector compared with liquid propellant and in the point of view of influenced by the size of droplet diameter on the gel propulsion system. Considering the shear thinning effect of the gel propellant and ability to atomization of gelled propellant by swirl injector, to improve the quality of the atomization of gel propellant, the design of the swirl injector should be such that the shear rate applied on the gel propellant should be increased to conquer the initial viscosity of the gel.