A 1 kW-class arcjet thruster was fired in a vacuum chamber at a pressure of 18 Pa. A gas mixture of H2 ： N2 = 2.8 ： 1.5 in volume at a total flow rate of 4.3 slm was used as the propellant with an input power fixed ...A 1 kW-class arcjet thruster was fired in a vacuum chamber at a pressure of 18 Pa. A gas mixture of H2 ： N2 = 2.8 ： 1.5 in volume at a total flow rate of 4.3 slm was used as the propellant with an input power fixed at 860 W. The time-dependent thrust, nozzle temperature and inlet pressure of the propellant were measured simultaneously. Results showed that with the increase in nozzle temperature the thrust decreased and various losses increased. The physical mechanisms involved in these effects are discussed.展开更多
Gasdynamic flow features in an electrothermal arcjet thruster with a mixture of 1：2 nitrogen/hydrogen as the working gas have been studied by a two-temperature numerical simulation.Seven species and 17 kinetic proces...Gasdynamic flow features in an electrothermal arcjet thruster with a mixture of 1：2 nitrogen/hydrogen as the working gas have been studied by a two-temperature numerical simulation.Seven species and 17 kinetic processes are included in the chemical kinetic model used to represent dissociation, ionization, and the corresponding recombination reactions in this nitrogen/hydrogen mixture system. Based on the gas flow characteristics inside the arcjet nozzle,a new method is introduced to define the edge of the cold boundary layer, which is more convenient to analyze the evolution and development of plasma flow in an arcjet thruster. The results show that the arcjet thruster performance is determined largely by the exchange of energy and momentum between the low-density, high-temperature arc region and the high-density, coolflow region near the nozzle wall. A significant thermal nonequilibrium is found in the cold boundary layer in the expansion portion of the nozzle. The important chemical kinetic processes determining the distribution of hydrogen and nitrogen species in different flow regions are presented. It has been shown that the reaction rate of hydrogen species ionization impacted by electrons is much higher than that of nitrogen species ionization in the center of the constrictor of the arcjet thruster. This indicates that hydrogen species is very important in the conversion of applied electric energy into thermal energy in the constrictor region of the arcjet thruster.展开更多
基金supported by National Natural Science Foundation of China (Nos.50836007, 10775164 and 10921062)
文摘A 1 kW-class arcjet thruster was fired in a vacuum chamber at a pressure of 18 Pa. A gas mixture of H2 ： N2 = 2.8 ： 1.5 in volume at a total flow rate of 4.3 slm was used as the propellant with an input power fixed at 860 W. The time-dependent thrust, nozzle temperature and inlet pressure of the propellant were measured simultaneously. Results showed that with the increase in nozzle temperature the thrust decreased and various losses increased. The physical mechanisms involved in these effects are discussed.
基金Supported by National Natural Science Foundation of China(Grant Nos.11575019,11275021)
文摘Gasdynamic flow features in an electrothermal arcjet thruster with a mixture of 1：2 nitrogen/hydrogen as the working gas have been studied by a two-temperature numerical simulation.Seven species and 17 kinetic processes are included in the chemical kinetic model used to represent dissociation, ionization, and the corresponding recombination reactions in this nitrogen/hydrogen mixture system. Based on the gas flow characteristics inside the arcjet nozzle,a new method is introduced to define the edge of the cold boundary layer, which is more convenient to analyze the evolution and development of plasma flow in an arcjet thruster. The results show that the arcjet thruster performance is determined largely by the exchange of energy and momentum between the low-density, high-temperature arc region and the high-density, coolflow region near the nozzle wall. A significant thermal nonequilibrium is found in the cold boundary layer in the expansion portion of the nozzle. The important chemical kinetic processes determining the distribution of hydrogen and nitrogen species in different flow regions are presented. It has been shown that the reaction rate of hydrogen species ionization impacted by electrons is much higher than that of nitrogen species ionization in the center of the constrictor of the arcjet thruster. This indicates that hydrogen species is very important in the conversion of applied electric energy into thermal energy in the constrictor region of the arcjet thruster.
