The aim of present study is to investigate the burning rate,ignition delay,and flame characteristics of ammonium perchlorate(AP)-hydroxyl terminated poly-butadiene(HTPB)[AP/HTPB]based composite propellants(CSP's)i...The aim of present study is to investigate the burning rate,ignition delay,and flame characteristics of ammonium perchlorate(AP)-hydroxyl terminated poly-butadiene(HTPB)[AP/HTPB]based composite propellants(CSP's)in sub-atmospheric pressure regimes(13 kPae100 kPa).Several fuels and catalyzed were used to evaluate their effects on the combustion characteristics of AP based propellants in sub-atmospheric pressure regimes.In fuels,aluminum(Al)and boron(B)were selected as metallic and non-metallic fuel respectively.While in catalyst,butyl ferrocene(B.F.)and ferric oxide(F.O.)were selected as liquid and solid catalyst respectively.Apart from these,other ingredients that were used are di-octyl adipate(DOA),toluene di-isocyanate(TDI),and glycerol.The article throws some light on the burning rate and ignition delay properties for these new classes of prepared propellant samples.At subatmospheric pressures,all propellants are susceptible to irregular burning with the ejection of soot's,fumes,and unburned particles.F.O.based catalyzed propellants can sustain its combustion up to the lowest pressure.展开更多
In this paper,an efficient boundary condition is applied to solve the photoionization rate,and a two-dimensional numerical simulation is carried out for the development and propagation of an air streamer at low temper...In this paper,an efficient boundary condition is applied to solve the photoionization rate,and a two-dimensional numerical simulation is carried out for the development and propagation of an air streamer at low temperature and sub-atmospheric pressure.The results show that the new boundary condition improves the calculation accuracy,but the influence of photoionization on the streamer discharge process is not obvious.The discharge current in the development of streamer discharge is defined,and the corresponding expression of the positive and negative streamer discharge current is given.The influence of the electric field exceeding the threshold value on the discharge process is preliminarily introduced.In the process of discharge,only the propagation velocity of the streamer is obviously higher than that of normal temperature and pressure,and the trend of the other parameters is basically the same as that described in the previous paper.The above results give us a deeper understanding of the discharge characteristics under low temperature and sub-atmospheric pressure,which has certain significance for the development of aviation and high voltage engineering.展开更多
In order to effectively widen the high-altitude operating limits of the multi-swirl staged combustor,the ignition and lean blow-out(LBO)performances of the model combustor were experimentally acquired under the condit...In order to effectively widen the high-altitude operating limits of the multi-swirl staged combustor,the ignition and lean blow-out(LBO)performances of the model combustor were experimentally acquired under the conditions of room temperature and sub-atmospheric pressure with the altitude ranging from 0 km to 12 km.Moreover,the isothermal flow fields inside a staged model combustor with different sub-atmospheric conditions were simulated.Experimental results show that the minimum ignition and LBO fuel-air ratio(FAR)increase rapidly with the increase of simulated altitude.In addition,as the relative pressure drop of injector increases from1%to 3%,the ignition and LBO performances are gradually improved.Side visualization of the flame by high-speed camera shows that the time-averaged flames under stable combustion have a similar distribution pattern under different pressure drops.The luminous intensity is stratified into dim-bright-dim layers along axial direction.The flame near LBO shrinks to the outlet of pilot stage with a great reduction in luminous intensity.The numerical results reveal that with the decrease of air pressure,the air mass flow rate involved in atomization and combustion is significantly reduced,and the aerodynamic shear force of swirling air is weakened,which are adverse to atomization and fuel-air mixing for airblast atomizer and further lead to the deterioration of ignition and LBO performances.展开更多
文摘The aim of present study is to investigate the burning rate,ignition delay,and flame characteristics of ammonium perchlorate(AP)-hydroxyl terminated poly-butadiene(HTPB)[AP/HTPB]based composite propellants(CSP's)in sub-atmospheric pressure regimes(13 kPae100 kPa).Several fuels and catalyzed were used to evaluate their effects on the combustion characteristics of AP based propellants in sub-atmospheric pressure regimes.In fuels,aluminum(Al)and boron(B)were selected as metallic and non-metallic fuel respectively.While in catalyst,butyl ferrocene(B.F.)and ferric oxide(F.O.)were selected as liquid and solid catalyst respectively.Apart from these,other ingredients that were used are di-octyl adipate(DOA),toluene di-isocyanate(TDI),and glycerol.The article throws some light on the burning rate and ignition delay properties for these new classes of prepared propellant samples.At subatmospheric pressures,all propellants are susceptible to irregular burning with the ejection of soot's,fumes,and unburned particles.F.O.based catalyzed propellants can sustain its combustion up to the lowest pressure.
基金supported by the No.703 Research Institute of CSIC(China Shipbuilding Industry Corporation)and Yunnan Electric Test&Research Institute Group CO.,Ltd.
文摘In this paper,an efficient boundary condition is applied to solve the photoionization rate,and a two-dimensional numerical simulation is carried out for the development and propagation of an air streamer at low temperature and sub-atmospheric pressure.The results show that the new boundary condition improves the calculation accuracy,but the influence of photoionization on the streamer discharge process is not obvious.The discharge current in the development of streamer discharge is defined,and the corresponding expression of the positive and negative streamer discharge current is given.The influence of the electric field exceeding the threshold value on the discharge process is preliminarily introduced.In the process of discharge,only the propagation velocity of the streamer is obviously higher than that of normal temperature and pressure,and the trend of the other parameters is basically the same as that described in the previous paper.The above results give us a deeper understanding of the discharge characteristics under low temperature and sub-atmospheric pressure,which has certain significance for the development of aviation and high voltage engineering.
基金supported by National Science and Technology Major Project with Project No.2017-Ⅲ-0007-0032。
文摘In order to effectively widen the high-altitude operating limits of the multi-swirl staged combustor,the ignition and lean blow-out(LBO)performances of the model combustor were experimentally acquired under the conditions of room temperature and sub-atmospheric pressure with the altitude ranging from 0 km to 12 km.Moreover,the isothermal flow fields inside a staged model combustor with different sub-atmospheric conditions were simulated.Experimental results show that the minimum ignition and LBO fuel-air ratio(FAR)increase rapidly with the increase of simulated altitude.In addition,as the relative pressure drop of injector increases from1%to 3%,the ignition and LBO performances are gradually improved.Side visualization of the flame by high-speed camera shows that the time-averaged flames under stable combustion have a similar distribution pattern under different pressure drops.The luminous intensity is stratified into dim-bright-dim layers along axial direction.The flame near LBO shrinks to the outlet of pilot stage with a great reduction in luminous intensity.The numerical results reveal that with the decrease of air pressure,the air mass flow rate involved in atomization and combustion is significantly reduced,and the aerodynamic shear force of swirling air is weakened,which are adverse to atomization and fuel-air mixing for airblast atomizer and further lead to the deterioration of ignition and LBO performances.
