A Study of The Start Up Delay for Low-Thrust Hydrazine Thrusters

• Main Authors: Yao Chia-Hsing, 姚嘉信
• Other Authors: 袁曉峰
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/71257213337300894845

碩士 === 國立成功大學 === 航空太空工程學系 === 88 === Abstract This thesis research has completed the design, fabrication and hot firing tests of a 1-lbf-monopropellant hydrazine thrusters. The design of this thruster was based on the experimental data from previous researches of this laboratory. The design 1-lbf thruster was equipped with a single-tube (16-orifice) radial type injector and packed with 8.1g Shell 405 catalyst. Two different kinds of packing were used in this research. Group A filled with smaller size (20~25mesh) of Shell 405 on the top of the catalyst bed and larger size (14~18mesh) in the bottom, and group B was reversed. After 39 thrust tests (at atmospheric back pressure) with four catalyst pre-heated temperatures, the results showed (1) At the propellant flow rate about 0.005 lbm/sec, group A produced 193.0~200.2psia of chamber pressure and 0.56~0.81 lbf of ground thrust. The pressures were 10.6% and 6.5% lower than the expectation. Group B produced 223.0~233.9psia chamber pressure and 0.64~0.66 lbf ground thrust which was 3.95% and 4.8% over the expectation, respectively. (1) The response characteristics of the thruster was invariant when the catalyst bed temperatures reached about 80℃with the propellant flow rate about 0.005 lbm/sec. However, the response characteristics of the thruster was improved with lower propellant flow rates as the temperature of the catalyst bed increased. (3) As a whole, the sequence of the packing of the two different sizes of catalyst did not show pronounced effect on thrusters response characteristics. At the propellant flow rate near 0.005 lbm/sec, group A had the best start-up delay time (33.7ms) when the temperature of the catalyst bed was 80℃. (4) After subtracting the response time of the solenoid valve and that of the induction time for the reactions, the response time of group A and B were 18.2~46.3ms and 18.8~45.2ms, respectively. Both of them were better then the 1-lbf-monopropellant hydrazine thruster from the previous researches of this laboratory. (5) The designed hydrazine thruster was estimated to obtain a ideal vacuum thrust of ~1-lbf and a ideal specific impulse of ~200sec at the designed propellant flow rate of 0.005 lbm/sec. This research indicated that the response characteristics of the catalyst bed packed with two different sizes was better then that with single size.