As the earliest electric propulsion device used in spacecraft,Pulsed Plasma Thruster(PPT)has the advantages of high specific impulse,small size,simple structure and light weight to meet the increasingly strict demands of space propulsion.However,due to its inefficiency,the research of searching for new solid propellant to improve PPT’s performance has been put forward in recent years.Therefore,the traditional propellant(PTFE)doped with copper and carbon(PTFE-Cu and PTFE-C)is carried out to study its impact on the performance of PPT in this paper.Through PPT performance tests and mechanism tests,and the infrared radiation experiments,the different proportion of the specific impulse and efficiency of PPT and the infrared radiation preliminary test of propellant ablation wall temperature were carried out,which could be the experimental techniques and data support for the study of ablation mechanism of solid polymer.In this paper,PTFE-Cu and PTFE-C were selected as the research objects,the mass ratio is 2%,5%(6%),10%and 15%.At discharge voltages of 1000,1200 and 1500 V,the performance parameters like ablation mass,discharge voltage,discharge current were measured and impulse bit,specific impulse,efficiency were calculated to analyze the influence of different proportions.The results show that for PTFE-C,carbon content of 2%has the best performance at discharge voltages of 1500 V,specific impulse increased from654s(PTFE)to 758s,and the efficiency increased from 6.82%(PTFE)7.36%.For PTFE-Cu,copper content of 10%has the best PPT performance at discharge voltages of 1500 V,specific impulse increased from 654s(PTFE)to 704s,and efficiency increased from 6.82%(PTFE)to 8.14%.In this paper,the new solid propellant(PTFE-C2%,6%and PTCE-Cu2%,10%)was chose to take experiments about plasma spectroscopy test.At the distance of 3mm from propellant surface,the spectral intensities of C,F and Cu were measured and the plasma electron temperature and number density were calculated to analyze plasma characteristics.The results show that for the PTFE-C and PTFE-Cu,the intensity of the plasma,the content of the C and F particles and the electron number density increase,indicating that carbon promote the ionization process to some extent.For PTFE-Cu,the intensity of the plasma,the content of the C and F particles and the electron number density increase,Cu particles appear in the form of Cu+and Cu++,indicating that copper promote the ionization process to some extent.The ablation wall temperature test were also carried out in this paper.A set of infrared temperature measurement equipment was designed and constructed based on the existing equipment in the laboratory and the characteristics of PPT.The infrared radiation test of alcohol lamp was carried out.The feasibility of the test system was verified by the experimental infrared spectral wavelength data.Infrared radiation measurement of ablated working wall surface during the pulsed operation of PPT were done to test problems compared with preliminary test results and previous experimental data.The test system of this test is affected by the interference of the plasma plume and the weak signal in the discharge channel of PPT,which will affect the accuracy of the test data and propose the improved scheme of optical path and detector. |