The Al and La elements are added to the Sn9Zn alloy to obtain the fusible alloy for the mitigation devices of solid propellant rocket motors. Differential scanning calorimetry(DSC), metallographic analysis,scanning el...The Al and La elements are added to the Sn9Zn alloy to obtain the fusible alloy for the mitigation devices of solid propellant rocket motors. Differential scanning calorimetry(DSC), metallographic analysis,scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), tensile testing and fracture analysis were used to study the effect of Al and La elements on the microstructure, melting characteristics, and mechanical properties of the Sn9Zn alloy. Whether the fusible diaphragm can effectively relieve pressure was investigated by the hydrostatic pressure at high-temperature test. Experimental results show that the melting point of the Sn9Zn-0.8Al0·2La and Sn9Zn-3Al0·2La fusible alloys can meet the predetermined working temperature of ventilation. The mechanical properties of those are more than 35% higher than that of the Sn9Zn alloy at-50°C-70°C, and the mechanical strength is reduced by 80% at 175°C. It is proven by the hydrostatic pressure at high-temperature test that the fusible diaphragm can relieve pressure effectively and can be used for the design of the mitigation devices of solid propellant rocket motors.展开更多
The main purpose of the present work is to study the possibilities of reducing calculation time while maintaining the validity in the numerical simulation of the combustion product flow in SPRM chamber.Three ways of d...The main purpose of the present work is to study the possibilities of reducing calculation time while maintaining the validity in the numerical simulation of the combustion product flow in SPRM chamber.Three ways of decreasing the calculation time-the use of numerical methods of high accuracy order,the reduction in spatial dimension of the problem,and the use of physical features of the processes in SPRM chamber while constructing a calculation model-were considered.Presented calculation data show that the use of these approaches makes it possible to reduce the time for solving the problems of SPRM simulation significantly(up to 100times).Also conclusions about the applicability of the mentioned above approaches in SPRM design were made.展开更多
To efficiently compute arbitrary propellant grain evolution of the burning surface with uniform and non-uniform burning rate for solid rocket motor,a unified framework of burning surface regression simulation has been...To efficiently compute arbitrary propellant grain evolution of the burning surface with uniform and non-uniform burning rate for solid rocket motor,a unified framework of burning surface regression simulation has been developed based on minimum distance function.In order to speed up the computation of the mini-mum distance between grid nodes of grain and the triangular mesh of burning surface,a fast distance querying method based on the equal size cube voxel structure was employed.An improved marching tetrahedron method based on piecewise linear approximation was carried out on second-order tetrahedral elements,achieved high-efficiency and adequate accuracy of burning surface extraction simultaneously.The cases of star grain,finocyl grain,and non-uniform tube grain were studied to verify the proposed method.The observed result indicates that the grain burnback computation method could realize the accurate simulation on unstructured tetrahedral mesh with a desirable performance on computational time.展开更多
The pintle valve is currently the most promising technology among all thrust control methods for solid rocket motors.Pintle structure and working condition play a critical role in the successful operation of a pintle ...The pintle valve is currently the most promising technology among all thrust control methods for solid rocket motors.Pintle structure and working condition play a critical role in the successful operation of a pintle motor.Here,2D transient simulations of a pintle motor using dynamic meshing are performed.Reynolds-averaged Navier–Stokes equations are solved with the implementation of an RNG k–e turbulence model.In cold flow test,emphasis is placed on the effect of pintle structure,and in hot flow test,emphasis is placed on the effect of propellant pressure exponent.Validation is performed first by comparing the present results with available cold-test experimental data.This shows that the transient simulations can provide good predictions for pintle motors with a relative error of less than 2%in terms of the chamber pressure.It can be found that,when the gas supply system is different,the working principles and conditions of pintle motors are different.The feedback process in propellant combustion has a significant impact on its operation and the effect on the pintle motor performance of different pintle structures is achieved by different variations in the equivalent throat area.Finally,the pressure exponent is an important parameter in hot flow test and changes of thrust in hot flow test are not monotonic,because changes in the flow field and motor performance are asynchronous.展开更多
This paper presents the topic of using solid rocket propulsion for de-orbiting spacecraft,in order to fulfil space debris mitigation requirements.The benefits and disadvantages of using such means are discussed.A dedi...This paper presents the topic of using solid rocket propulsion for de-orbiting spacecraft,in order to fulfil space debris mitigation requirements.The benefits and disadvantages of using such means are discussed.A dedicated system can be implemented in the satellite design phase and shall be a key subsystem of platforms inserted into orbit.Uncontrolled,semi-controlled and controlled de-orbit can be completed using solid rocket motors.Their impact on the space debris environment is discussed.Specific requirements for dedicated propellants and systems are provided.While the majority of presently developed rocket systems worldwide require high burn rates,several applications,including de-orbiting,benefit from solid propellants with decreased regression rates.This allows limiting spacecraft accelerations and loads during de-orbit manoeuvres.Moreover,the requirement of minimising solid particle generation is presented.Heritage technology from the Mercury and Gemini human spaceflight programmes,where de-orbit motors were used,is shown.Historical Soviet,American and Chinese film-return-capsule solid propellant retrorockets,enabling deorbit,are also presented.A detailed survey of current work worldwide on end-of-life disposal using solid propulsion is included.Challenges of developing dedicated systems are discussed.Finally,an outlook on solid rocket motor utilisation for space debris mitigation is provided.展开更多
基金the National Natural Science Foundation of China (Grant No. 11772058)。
文摘The Al and La elements are added to the Sn9Zn alloy to obtain the fusible alloy for the mitigation devices of solid propellant rocket motors. Differential scanning calorimetry(DSC), metallographic analysis,scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), tensile testing and fracture analysis were used to study the effect of Al and La elements on the microstructure, melting characteristics, and mechanical properties of the Sn9Zn alloy. Whether the fusible diaphragm can effectively relieve pressure was investigated by the hydrostatic pressure at high-temperature test. Experimental results show that the melting point of the Sn9Zn-0.8Al0·2La and Sn9Zn-3Al0·2La fusible alloys can meet the predetermined working temperature of ventilation. The mechanical properties of those are more than 35% higher than that of the Sn9Zn alloy at-50°C-70°C, and the mechanical strength is reduced by 80% at 175°C. It is proven by the hydrostatic pressure at high-temperature test that the fusible diaphragm can relieve pressure effectively and can be used for the design of the mitigation devices of solid propellant rocket motors.
基金the sponsors of the conference for financial support
文摘The main purpose of the present work is to study the possibilities of reducing calculation time while maintaining the validity in the numerical simulation of the combustion product flow in SPRM chamber.Three ways of decreasing the calculation time-the use of numerical methods of high accuracy order,the reduction in spatial dimension of the problem,and the use of physical features of the processes in SPRM chamber while constructing a calculation model-were considered.Presented calculation data show that the use of these approaches makes it possible to reduce the time for solving the problems of SPRM simulation significantly(up to 100times).Also conclusions about the applicability of the mentioned above approaches in SPRM design were made.
基金the National Natural Science Foundation of China(No.11202224)。
文摘To efficiently compute arbitrary propellant grain evolution of the burning surface with uniform and non-uniform burning rate for solid rocket motor,a unified framework of burning surface regression simulation has been developed based on minimum distance function.In order to speed up the computation of the mini-mum distance between grid nodes of grain and the triangular mesh of burning surface,a fast distance querying method based on the equal size cube voxel structure was employed.An improved marching tetrahedron method based on piecewise linear approximation was carried out on second-order tetrahedral elements,achieved high-efficiency and adequate accuracy of burning surface extraction simultaneously.The cases of star grain,finocyl grain,and non-uniform tube grain were studied to verify the proposed method.The observed result indicates that the grain burnback computation method could realize the accurate simulation on unstructured tetrahedral mesh with a desirable performance on computational time.
基金supported by the National Natural Science Foundation of China(No.11572042)。
文摘The pintle valve is currently the most promising technology among all thrust control methods for solid rocket motors.Pintle structure and working condition play a critical role in the successful operation of a pintle motor.Here,2D transient simulations of a pintle motor using dynamic meshing are performed.Reynolds-averaged Navier–Stokes equations are solved with the implementation of an RNG k–e turbulence model.In cold flow test,emphasis is placed on the effect of pintle structure,and in hot flow test,emphasis is placed on the effect of propellant pressure exponent.Validation is performed first by comparing the present results with available cold-test experimental data.This shows that the transient simulations can provide good predictions for pintle motors with a relative error of less than 2%in terms of the chamber pressure.It can be found that,when the gas supply system is different,the working principles and conditions of pintle motors are different.The feedback process in propellant combustion has a significant impact on its operation and the effect on the pintle motor performance of different pintle structures is achieved by different variations in the equivalent throat area.Finally,the pressure exponent is an important parameter in hot flow test and changes of thrust in hot flow test are not monotonic,because changes in the flow field and motor performance are asynchronous.
基金financed by the Polish National Agency for Academic Exchange(No.PPI/APM/2018/1/00032/U/001)Work presented from projects of ESA includes work done during preliminary phases of ASPro(Pre-Qualification of Aluminium-Free Solid Propellant)and SPRODEM(Solid Propellant De-orbit Motor Engineering Model Development)projects funded within the General Support Technology Programme(GSTP)。
文摘This paper presents the topic of using solid rocket propulsion for de-orbiting spacecraft,in order to fulfil space debris mitigation requirements.The benefits and disadvantages of using such means are discussed.A dedicated system can be implemented in the satellite design phase and shall be a key subsystem of platforms inserted into orbit.Uncontrolled,semi-controlled and controlled de-orbit can be completed using solid rocket motors.Their impact on the space debris environment is discussed.Specific requirements for dedicated propellants and systems are provided.While the majority of presently developed rocket systems worldwide require high burn rates,several applications,including de-orbiting,benefit from solid propellants with decreased regression rates.This allows limiting spacecraft accelerations and loads during de-orbit manoeuvres.Moreover,the requirement of minimising solid particle generation is presented.Heritage technology from the Mercury and Gemini human spaceflight programmes,where de-orbit motors were used,is shown.Historical Soviet,American and Chinese film-return-capsule solid propellant retrorockets,enabling deorbit,are also presented.A detailed survey of current work worldwide on end-of-life disposal using solid propulsion is included.Challenges of developing dedicated systems are discussed.Finally,an outlook on solid rocket motor utilisation for space debris mitigation is provided.
