| Micro-nano satellite plays an important role in the fields of scientific research,national defense and commercial due to its advantages of small size,low-power,short research cycle and formation networking.However,to date,only limited maneuverability is available for micro-nano satellite.For the tasks of attitude or orbit control,there is still a lack of effective power system.Laser-controlled solid propellant（LCSP）is a novel solid energetic material capable of ignition,extinction and burning rate control.It solves the problem that traditional chemical propellant is difficult to extinguish and restart repeatedly,which can satisfy the demands of micro-nano satellite for power system.In this paper,a solid propellant formula capable of controllable combustion was developed based on ammonium perchlorate（AP）and ammonium nitrate（AN）.Subsequently,the possible influenced factors of controllable combustion performance were analyzed and the corresponding controllable combustion law was mastered.Furthermore,the specific impulse augmented technology research was conducted to solve the disadvantage of low specific impulse for chemical propellant.The results are as follows:（1）The propellant formula composed of oxidizer,gas generator,light absorber and other functional additives was determined.Meanwhile,the corresponding preparation process was designed.Based on the characteristics of high burning rate（AP）and strong combustion controllability（AN）,the effect of AP and AN content on the controllable combustion characteristics was investigated in atmospheric environment.Finally,the optimized formula of LCSP was determined as:AP/AN/5-ATZ/Nano-Carbon/GAP/PF=46.18/30/20.82/3/3/2.（2）The multiple ignition and combustion of LCSP were successfully realized in transparent micro-thruster.Meanwhile,the ignition,combustion and thrust performance of LCSP in atmospheric environment were analyzed.The results show that the burning rate and combustion chamber pressure increased with the laser power density,whereas the ignition delay time revealed opposite trend.The thrust of LCSP was 1.58 mN～2.28 mN with the laser power density ranging from 0.344 W·mm-2 to 1.343 W·mm-2.Moreover,the combustion wave structure of LCSP was divided into five zones:pre-heating zone,condensed phase,optical-thermal reaction zone,gases mixing zone and flame zone.（3）The ignition and combustion characteristics of LCSP under high pressure were studied.With the laser power density range of 0.495 W·mm-2～1.379 W·mm-2and the ambient pressure range of 0.2 MPa～1.0 MPa,the burning rate and ignition delay time of LCSP were 1.30 mm·s-1～4.28 mm·s-1 and 1.84 s～0.87 s,respectively.The gas-solid ignition model of LCSP was established by combining the laser ignition process.Meanwhile,on the basis of the granular diffusion flame（GDF）combustion model,the theoretical expression of the burning rate under laser irradiation was obtained.The average deviation between the calculated and experimental results was 11.8%.（4）The effects of laser power density,ambient pressure and laser ignition time on propellant combustion controllability were studied.The combustion state of LCSP was divided into multiple regions.Furthermore,the controlling mechanism of laser energy and ambient pressure for controllable combustion was analyzed.The results show that the increased ambient pressure and the decreased laser power density predisposed the propellant to uncontrollable self-sustaining combustion.While,the laser ignition time would not affect the combustion state of LCSP.（5）The specific impulse augmented technology based on electromagnetic acceleration was studied.By contrasting the discharge current and thrust results of LCSP and PTFE propellant,the improvement effect of electromagnetic acceleration on specific impulse was verified.Subsequently,the energy contribution during electromagnetic acceleration was calculated.The contribution of laser energy was about 3%.Additionally,the electric energy was less than 17%and the chemical energy was more than 80%. |
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