Formulation Design And Performance Adjustment Of AP/HTPB-based Gas Generating Agents

The gas generating agents for missile ejector should have high burning rate,low combustion temperature,high gas-generating capacity and low residue ratio performance.The formulation design and performance optimization were carried out,by means of the thermodynamic calculations and experimental studies.The content of Ammonium perchlorate?AP?,Hydroxyl-terminated Polybutadiene?HTPB?and2,2-bis?ethylferrocenyl?propane were confirmed by the gas generating agents comprehensive performance.In this paper,the effect of the coolants,porous energetic materials and energetic salt compounds for gas generating agent were studied.The results show that,the burning rate of the AP/HTPB-based gas generating agents increase obviously when the content of GFP increases suitably.With the GFP content of 3%wt,the mass ratio of basic formulation that AP?HTPB?GFP is 80?17?3,the theoretical combustion temperature is 2124?,the burning rate is24.69mm·s^-1 at 10MPa,the gas generating capacity is 633.9L·kg^-1,the residue ratio is7.64%wt,and the gas generating rate is 36.72 MPa·s^-1.Both the coolants and the energetic salt compounds can reduce the combustion temperature of AP/HTPB-based gas generating agents.Among of them,the most significant offect of reducing combustion temperature are Oxamine?OXM?and the Oxysalt HN-M.The combustion temperature of the gas generating agents with 10%wt OXM is 1455?.The combustion temperature of the gas generating agents with20%wt HN-M is 1196?.The burning rates of AP/HTPB-based gas generating agents can be significantly improved by the porous energetic material PS₃ and the Azo salt HN-A.At 10MPa,the burning rate of the gas generating agents with 4%wt porous energetic material PS₃ is30.45mm·s^-1,which increases 5.76mm·s^-1 comparing with the basic formulation,and the increasing rate is 23.33%.At 10MPa,the burning rate of the gas generating agent with HN-A is 31.02mm·s^-1,which increases 6.33mm·s^-1 comparing with the basic formulation,and the increasing rate is 25.64%.The porous energetic materials and the energetic salt compounds can improve the gas generating capacity of AP/HTPB-based gas generating agents.Among of them,the most significant effect on increasing the gas generating capacity are the porous energetic materials PS₃ and the Oxysalt HN-N₂.The gas generating capacity of the gas generating agents with 4%wt PS₃ is 698.0L·kg^-1 which increases 64.1L·kg^-1comparing with the basic formulation,and the increasing rate is 10.1%.The gas generating capacity of the gas generating agents with 20%wt HN-N₂ is 705.0L·kg^-1,which increases 71.1L·kg^-1 comparing with the basic formulation,and the increasing rate is 11.2%.When AP is partially replaced by the coolants,porous energetic materials and the energetic salt compounds,the residue ratios of the AP/HTPB-based gas generating agents increase.The residue ratio of the gas generating agent with 4%wt porous energetic material PD₂ is lowest,and the residue rate is 7.73%wt.HN-A can increases the burning rate and reduces the burning temperature.When the formulation mass ratio AP?HN-A?HTPB?GFP is 60?20?17?3,the combustion temperature is 1259?,the burning rate is 31.02mm·s^-1 at 10MPa,the gas generating capacity is 693.4L·kg^-1 and the residue ratio is 22.46%wt.