One of the most important characteristic signatures of the exhaust plume from rocket motor is the aflerbuming phenomenon, and the injected water into the plume could inhibit the afterburning. The calculation model for...One of the most important characteristic signatures of the exhaust plume from rocket motor is the aflerbuming phenomenon, and the injected water into the plume could inhibit the afterburning. The calculation model for the gas-liquid multiphase flow field with chemical reaction in the plume is built. By inducing the energy source terms caused by the vaporization of liquid water, condensation of the vapor and chemical reaction in the energy equation, the gas-liquid multiphase flow field and the afterburning phenomenon are calculated in a coupling way. Mixture multiphase flow model is used to calculate the gas-liquid flow field, and the vaporization mechanism is used to investigate the water vaporization process. The temperature contours are obtained and accord well with the experimental photos. The mass fraction contours of primary species are obtained, which can indicate the extent of inhibition effect of water injection on the afterburning phenomenon in the plume. When water is injected into the plume, the region of aflerburning reduces a lot, and temperature on the ground wall declines rapidly, which can decrease the ablation of the combustion gas to the launch ground.展开更多
This paper describes the orbit design of the deployable payload Rover 2 of MINERVA-II,installed on the Hayabusa2 spacecraft.Because Rover 2 did not have surface exploration capabilities,the operation team decided to e...This paper describes the orbit design of the deployable payload Rover 2 of MINERVA-II,installed on the Hayabusa2 spacecraft.Because Rover 2 did not have surface exploration capabilities,the operation team decided to experiment with a new strategy for its deployment to the surface.The rover was ejected at a high altitude and made a semi-hard landing on the surface of the asteroid Ryugu after several orbits.Based on the orbital analysis around Ryugu,the expected collision speed was tolerable for the rover to function post-impact.Because the rover could not control its position,its motion was entirely governed by the initial conditions.Thus,the largest challenge was to insert the rover into a stable orbit(despite its large release uncertainty),and avoid its escape from Ryugu due to an environment strongly perturbed by solar radiation pressure and gravitational irregularities.This study investigates the solution space of the orbit around Ryugu and evaluates the orbit’s robustness by utilizing Monte Carlo simulations to determine the orbit insertion policy.Upon analyzing the flight data of the rover operation,we verified that the rover orbited Ryugu for more than one period and established the possibility of a novel method for estimating the gravity of an asteroid.展开更多
文摘One of the most important characteristic signatures of the exhaust plume from rocket motor is the aflerbuming phenomenon, and the injected water into the plume could inhibit the afterburning. The calculation model for the gas-liquid multiphase flow field with chemical reaction in the plume is built. By inducing the energy source terms caused by the vaporization of liquid water, condensation of the vapor and chemical reaction in the energy equation, the gas-liquid multiphase flow field and the afterburning phenomenon are calculated in a coupling way. Mixture multiphase flow model is used to calculate the gas-liquid flow field, and the vaporization mechanism is used to investigate the water vaporization process. The temperature contours are obtained and accord well with the experimental photos. The mass fraction contours of primary species are obtained, which can indicate the extent of inhibition effect of water injection on the afterburning phenomenon in the plume. When water is injected into the plume, the region of aflerburning reduces a lot, and temperature on the ground wall declines rapidly, which can decrease the ablation of the combustion gas to the launch ground.
基金This work was partially supported by JSPS KAKENHI Grant(No.18H01628).
文摘This paper describes the orbit design of the deployable payload Rover 2 of MINERVA-II,installed on the Hayabusa2 spacecraft.Because Rover 2 did not have surface exploration capabilities,the operation team decided to experiment with a new strategy for its deployment to the surface.The rover was ejected at a high altitude and made a semi-hard landing on the surface of the asteroid Ryugu after several orbits.Based on the orbital analysis around Ryugu,the expected collision speed was tolerable for the rover to function post-impact.Because the rover could not control its position,its motion was entirely governed by the initial conditions.Thus,the largest challenge was to insert the rover into a stable orbit(despite its large release uncertainty),and avoid its escape from Ryugu due to an environment strongly perturbed by solar radiation pressure and gravitational irregularities.This study investigates the solution space of the orbit around Ryugu and evaluates the orbit’s robustness by utilizing Monte Carlo simulations to determine the orbit insertion policy.Upon analyzing the flight data of the rover operation,we verified that the rover orbited Ryugu for more than one period and established the possibility of a novel method for estimating the gravity of an asteroid.
