Safety Study Of New Green Propellant NOFBX

In this paper,from the perspective of the safety of the new green single-component propellant NOFBX,the energy characteristics of 5 propellant formulations were studied using an oxygen bomb calorimeter and a constant temperature calorimeter.Explosion characteristics of different propellant were investigated using high-speed cameras and pressure test systems.The minimum ignition energy test device and adiabatic calorimeter were used to learn the sensitivity characteristics of 2 propellants.Finally,an Engine commissioning experiment was designed to explore the application feasibility of NOFBX.The research results of NOFBX explosion energy are as follows:the results calculated by Hess Law show that when the CO₂ mass ratio in the mixed gas is 0%,2.44%,3.38%,9.09%and 33.33%,the maximum reaction heat values of the mixed gas are 6496.85k J/kg?6260.99k J/kg?6171.38k J/kg?5646.07k J/kg and 3705.24k J/kg.Through theoretical calculations and reaction heat values measured by two calorimeters,the combustion efficiency of NOFBX in the two calorimeters was calculated.The results show that the reaction heat values obtained by the three methods are basically the same.The combustion efficiency of the mixed gas in the constant temperature calorimeter is higher than that of the oxygen bomb calorimeter,and the average combustion efficiency can reach more than 96%.The research results of NOFBX explosion characteristics show that:the steady flame propagation speed of 5 propellants is about 2200m/s.When the CO₂ content in the propellant is between 0%?9.09%,the average value of its stable shockwave pressure is between 3.5MPa?4MPa.The shockwave velocity predicted by the C-J theory is2340m/s?2439m/s.The measured average velocity of the shockwave is 2137m/s?2341m/s.The experimental results show:The addition of a small amount of CO₂ will not affect the stable flame velocity and shockwave pressure of the mixed gas.The measured shockwave velocity is basically consistent with the theoretical value when the CO₂ content is 0 to 9.09%.The addition of excess CO₂ will have a strong weakening effect on the energy,shockwave pressure and shockwave velocity.That is to say,CO₂can be added into NOFBX to improve the safety of propellant.The results of the minimum ignition energy study are as follow:the minimum ignition energy of the mixed gas with CO₂ content of 0%and 2.44%are 0.25m J?0.5m J.The test results of the critical reaction temperature of mixed gas show that:The sample without CO₂ started to exotherm at 135?.After adding 2.44%CO₂,the sample became exothermic at 180?.The results show that with the addition of CO2,the thermal stability of NOFBX is significantly improved,which is consistent with the above test rules.The first engine test results show:At the moment of opening the solenoid valve,the fuel tank exploded.This paper starts from the structure and principles of the solenoid valve,analyzed the cause of the accident test After the solenoid valve was replaced,the second test run was success.