بررسی اثر افت فشار انژکتور بر عملکرد رانشگر تک‌پیشرانه هیدرازینی یک نیوتنی

ﻧﺘﺎﻳﺞ ﻣﻄﺎﻟﻌﻪ ﺗﺠﺮبی اﺛﺮ اﻓﺖ ﻓﺸﺎر روی رﻓﺘﺎر ﻳﻚ راﻧﺸﮕﺮ ﺗﻚﭘﻴﺸﺮاﻧﻪ ﻫﻴﺪرازینی در اﻳﻦ ﻣﻘﺎﻟﻪ اراﺋﻪ می ﺷﻮد. اﻧﮋﻛﺘﻮرﻫﺎی اﺳﺘﻔﺎده ﺷﺪه در اﻳﻦ راﻧﺸﮕﺮﻫﺎ از ﻧﻮع ارﻳﻔﻴﺲ ﻫﺴﺘﻨﺪ. ﻫﺮﭼﻨﺪ اﻟﮕﻮی ﺟﺮﻳﺎن ﺳﻴﺎل در اﻳﻦ اﻧﮋﻛﺘﻮرﻫﺎ ﻣﻤﻜﻦ اﺳﺖ ﺳﺎده ﺑﻪ ﻧﻈﺮ ﺑﺮﺳﺪ، ولی رﻓﺘﺎر راﻧﺸﮕﺮ، ﻛﻪ ﻧﺎشی از اﻧﺪرﻛﻨﺶ دﻳﻨﺎﻣﻴﻚ اﻧﮋﻛﺘﻮر ﺑﺎ ﻣﺤﻔﻈﻪ اﺳﺖ، وﻳﮋگی ﻫﺎی ﺟﺎﻟﺐ ﺗﻮجهی را ﻧﺸﺎن ﻣﻲدﻫﺪ. آزﻣﺎﻳﺶﻫﺎ ﻧﺸﺎن دادﻧﺪ ﻛﻪ اﻓﺖ ﻓﺸﺎر اﻧﮋﻛﺘﻮر، در ﻣﺤﺪودة ﻣﻮرد ﻣﻄﺎﻟﻌﻪ، ﺗﺄﺛﻴﺮی ﺑﺮ ﺳﺮﻋﺖ ﻣﺸﺨﺼﻪ و ﺗﺄﺧﻴﺮ اﺷﺘﻌﺎل ﻧﺪاﺷﺖ. ﺑﺎ اﻳﻦ ﺣﺎل زﻣﺎن ﭘﺎﺳﺦ 90% ﻓﺸﺎر و ﻧﻮﺳﺎن ﻓﺸﺎر ﻣﺤﻔﻈﻪ ﺑﻪ ﺷﺪت ﺗﺤﺖ اﺛﺮ اﻓﺖ ﻓﺸﺎر اﻧﮋﻛﺘﻮر ﻫﺴﺘﻨﺪ؛ ﺑﺎ اﻓﺰاﻳﺶ اﻓﺖ ﻓﺸﺎر، زﻣﺎن ﭘﺎﺳﺦ اﻓﺰاﻳﺶ ﻣﻲﻳﺎﺑﺪ اﻣﺎ ﻧﻮﺳﺎن ﻓﺸﺎر ﻛﻢ میﺷﻮد. ﻫﻤﭽﻨﻴﻦ ﻧﻤﻮدار زﻣﺎن ﭘﺎﺳﺦ - اﻓﺖ ﻓﺸﺎر اﻧﮋﻛﺘﻮر ﺑﻪ ﻃﺮز ﺟﺎلبی در اﻓﺖ ﻓﺸﺎر 20%، ﻳﻚ ﺗﻐﻴﻴﺮ ﺷﻴﺐ داﺷﺖ. ﻧﺘﺎﻳﺞ ﻧﺸﺎن ﻣﻲدﻫﺪ ﻛﻪ ﺗﻐﻴﻴﺮ ﺷﻴﺐ اﻳﻦ ﻧﻤﻮدار ﻧﺎﺷﻲ از رﻓﺘﺎر ﻏﻴﺮﺧﻄﻲ ﺳﺎﻣﺎﻧﻪ در زﻣﺎن اﺳﺘﺎرت اﺳﺖ ﻛﻪ ﭘﺪﻳﺪه ﻛﺎوﻳﺘﺎﺳﻴﻮن در آن ﻧﻘﺶ دارد. اﻳﻦ ﺗﻐﻴﻴﺮ ﺷﻴﺐ ﻧﻤﻮدار زﻣﺎن ﭘﺎﺳﺦ در راﻧﺸﮕﺮﻫﺎی ﺗﻚﭘﻴﺸﺮاﻧﻪ ﭘﻴﺶ از اﻳﻦ ﮔﺰارش ﻧﺸﺪه اﺳﺖ. ﻧﺘﺎﻳﺞ اراﺋﻪ ﺷﺪه ﺛﺎﺑﺖ ﻣﻲﻛﻨﺪ ﻛﻪ آزﻣﻮن ﺳﺮد اﻧﮋﻛﺘﻮر ﺑﺮای ارزﻳﺎﺑﻲ و ﺻﺤﻪﮔﺬاری ﻃﺮاﺣﻲ آن ﻛﺎفی ﻧﺒﻮده و اﻫﻤﻴﺖ ﺗﺴﺖ ﮔﺮم راﻧﺸﮕﺮ را ﻧﺸﺎن ﻣﻲدﻫﺪ.

effect of injector pressure drop on the performance of a 1 n monopropellant thruster

the effects of injector pressure drop on the performance of a catalytic reactor are studied experimentally. the injectors were simple orifices. dynamic interactions between the injector and the reactor determine the transient behavior of the system. results showed that the injector pressure drop affected neither the decomposition reaction efficiency nor the ignition delay time. however, pressure response time increased, and pressure roughness decreased with increasing injector pressure drop. interestingly, the response time curve had a slope change at a 20% pressure drop. as discussed in the paper, the slope change is a result of cavitation phenomena in high pressure drop. it is concluded that cold injector tests are not enough for injector design validation, and performance tests are necessary tasks.