Significance of body material and temperature variation on burning time and burning rate of Si/Pb O/Pb_3O_4/FG and B/BaCrO_4/FG pyrotechnic delay compositions were experimentally studied. Brass and stainless steel wer...Significance of body material and temperature variation on burning time and burning rate of Si/Pb O/Pb_3O_4/FG and B/BaCrO_4/FG pyrotechnic delay compositions were experimentally studied. Brass and stainless steel were used as delay body materials. High resolution oscilloscope and a customized chronometer were simultaneously used for the measurement of burning time and burning rate. Results reveal that brass material with controlled column dimensions reduced the variation in burning time of Si/Pb O/Pb_3O_4/FG delay mixture from 7.43% to 4.17% and that of B/Ba CrO_4/FG mixture from 16.83% to 9.39%.Similarly the variation in burning rate was reduced from 7.57% to 4.12% and from 17% to 9.69% for Si/Pb O/Pb_3O_4/FG and B/BaCrO_4/FG mixtures respectively. Si/PbO/Pb_3O_4/FG delay mixture was also subjected to temperature ranging from -54℃ up to+100℃. The burning rate of this composition varied linearly with temperature. Burning rate increased from 28.01 mm/s to 34.38 mm/s when the temperature was varied from -54℃ to +100℃.展开更多
The objective of the paper is to compute the optimal burn-out conditions and control requirements that would result in maximum down-range/cross-range performance of a waverider type hypersonic boost-glide(HBG) vehicle...The objective of the paper is to compute the optimal burn-out conditions and control requirements that would result in maximum down-range/cross-range performance of a waverider type hypersonic boost-glide(HBG) vehicle within the medium and intermediate ranges,and compare its performance with the performances of wing-body and lifting-body vehicles vis-a-vis the g-load and the integrated heat load experienced by vehicles for the medium-sized launch vehicle under study.Trajectory optimization studies were carried out by considering the heat rate and dynamic pressure constraints.The trajectory optimization problem is modeled as a nonlinear,multiphase,constraint optimal control problem and is solved using a hp-adaptive pseudospectral method.Detail modeling aspects of mass,aerodynamics and aerothermodynamics for the launch and glide vehicles have been discussed.It was found that the optimal burn-out angles for waverider and wing-body configurations are approximately 5° and 14.8°,respectively,for maximum down-range performance under the constraint heat rate environment.The down-range and cross-range performance of HBG waverider configuration is nearly 1.3 and 2 times that of wing-body configuration respectively.The integrated heat load experienced by the HBG waverider was found to be approximately an order of magnitude higher than that of a lifting-body configuration and 5 times that of a wing-body configuration.The footprints and corresponding heat loads and control requirements for the three types of glide vehicles are discussed for the medium range launch vehicle under consideration.展开更多
文摘Significance of body material and temperature variation on burning time and burning rate of Si/Pb O/Pb_3O_4/FG and B/BaCrO_4/FG pyrotechnic delay compositions were experimentally studied. Brass and stainless steel were used as delay body materials. High resolution oscilloscope and a customized chronometer were simultaneously used for the measurement of burning time and burning rate. Results reveal that brass material with controlled column dimensions reduced the variation in burning time of Si/Pb O/Pb_3O_4/FG delay mixture from 7.43% to 4.17% and that of B/Ba CrO_4/FG mixture from 16.83% to 9.39%.Similarly the variation in burning rate was reduced from 7.57% to 4.12% and from 17% to 9.69% for Si/Pb O/Pb_3O_4/FG and B/BaCrO_4/FG mixtures respectively. Si/PbO/Pb_3O_4/FG delay mixture was also subjected to temperature ranging from -54℃ up to+100℃. The burning rate of this composition varied linearly with temperature. Burning rate increased from 28.01 mm/s to 34.38 mm/s when the temperature was varied from -54℃ to +100℃.
基金the Chinese Scholarship Council for supporting the research
文摘The objective of the paper is to compute the optimal burn-out conditions and control requirements that would result in maximum down-range/cross-range performance of a waverider type hypersonic boost-glide(HBG) vehicle within the medium and intermediate ranges,and compare its performance with the performances of wing-body and lifting-body vehicles vis-a-vis the g-load and the integrated heat load experienced by vehicles for the medium-sized launch vehicle under study.Trajectory optimization studies were carried out by considering the heat rate and dynamic pressure constraints.The trajectory optimization problem is modeled as a nonlinear,multiphase,constraint optimal control problem and is solved using a hp-adaptive pseudospectral method.Detail modeling aspects of mass,aerodynamics and aerothermodynamics for the launch and glide vehicles have been discussed.It was found that the optimal burn-out angles for waverider and wing-body configurations are approximately 5° and 14.8°,respectively,for maximum down-range performance under the constraint heat rate environment.The down-range and cross-range performance of HBG waverider configuration is nearly 1.3 and 2 times that of wing-body configuration respectively.The integrated heat load experienced by the HBG waverider was found to be approximately an order of magnitude higher than that of a lifting-body configuration and 5 times that of a wing-body configuration.The footprints and corresponding heat loads and control requirements for the three types of glide vehicles are discussed for the medium range launch vehicle under consideration.
