Thrust and Specific Impulse Optimization of Eight-Centimeter Valveless Pulsejets at Low Subsonic Flight Speeds

subsonic;pulsejet;thrust;miniature;specific impulse

Boyette, Wesley Ryan ; Dr. William Roberts, Committee Chair,Dr. Terry Scharton, Committee Member,Dr. Andrey Kuznetsov, Committee Member,Boyette, Wesley Ryan ; Dr. William Roberts ; Committee Chair ; Dr. Terry Scharton ; Committee Member ; Dr. Andrey Kuznetsov ; Committee Member

University:North Carolina State University

关键词: subsonic;    pulsejet;    thrust;    miniature;    specific impulse;   

Others  :  https://repository.lib.ncsu.edu/bitstream/handle/1840.16/43/etd.pdf?sequence=1&isAllowed=y

美国|英语

来源: null

【 摘 要 】

The purpose of this research was to develop a method of accurately measuring the thrustand specific impulse of valveless pulsejets that are approximately eight centimeters inlength. Previous methods of doing such were largely unsuccessful. A vertically arrangedthrust stand and electronic balance were ultimately able to produce reliable results.Seven inlets were then tested on a forward facing arrangement. The maximum thrustachieved was 24.4 mN and specific impulse peaked at 295 seconds. Comparisonrevealed that increasing inlet length has a positive effect on pulsejet performance. Eachinlet was tested at simulated forward flight speeds as well, showing that shorter inletsperform optimally at lower speeds than longer inlets. Additionally, a relationshipbetween pulsejet performance, frequency and exhaust temperature was identified.Similar tests were performed on hybrid configurations as well, which combine forwardfacingand rearward-facing inlets. Of the five hybrid configurations tested, maximumthrust was 31.2 mN and maximum specific impulse was 232 seconds. This series of testsrevealed that these configurations also showed improvement in performance at higherforward flight speeds and at smaller inlet areas. In all cases, hydrogen was used as thefuel, due to its very short chemical time. Pulsejets at this scale are also shown to becapable of operating on acetylene, although with reduced performance.