Porous ionic liquid electrospray thrusters are the ideal propulsion technology for CubeSats because of their structural simplicity,high thrust accuracy and plume self-neutralization.The electrowetting technology can r...Porous ionic liquid electrospray thrusters are the ideal propulsion technology for CubeSats because of their structural simplicity,high thrust accuracy and plume self-neutralization.The electrowetting technology can replenish the propellant for the emitter online,thus prolonging the lifetime of the thruster.In order to gain a deeper understanding of its operating characteristics,the changes in thruster performance before and after propellant replenishment deserve to be scrutinized.In this study,the performance changes of a porous electrowetting ionic liquid electrospray thruster are tested by voltage-current test and time-of-flight mass spectrometry over a long operating time.The experimental results show that asymmetric operation with a negative current less than positive current for a long period of time causes anions to compensate for the emission after accumulation at the emitter,resulting in a phenomenon that the negative current is much larger than positive current.The reason for the difference in emission characteristics between the positive and negative modes is that the plume in the positive mode is quite ionized while the plume in the negative mode contains liquid droplets.This study provides a reference for the selection of operating conditions for ionic liquid electrospray thrusters.展开更多
The ionic liquid electrospray thruster is a microminiature thruster that can be applied on a micro or nano-satellite,and its highly energy-efficient,compact,modular system can be used for both main propulsion and alti...The ionic liquid electrospray thruster is a microminiature thruster that can be applied on a micro or nano-satellite,and its highly energy-efficient,compact,modular system can be used for both main propulsion and altitude control.In this study,an ionic liquid electrospray thruster with a 100-tip emitter configuration is tested primarily to examine the difference in performance of the thruster at different angles with time-of-flight(TOF)mass spectrometry tests.In the experiment,it was measured that the half-angle of the thruster plume angle emission was in the range of−60 degrees to+65 degrees.Accordingly,the measurement range was set from−50 degrees to+50 degrees,with an interval of 10 degrees.Relative to the results of the 0 degree current curve,the positive mode is relatively homogeneous at all angles of the operating mode.In the negative mode,for n 2 ions,the negative angle region accounts for a larger proportion and the positive angle region accounts for a smaller proportion,which makes a significant difference to the specific impulse of the two regions.The range of the specific impulse at different angles is 3776-4401 s under the typical working condition of+2.5 kV.Under−2.5 kV,the range of the specific impulse at different angles is 3309-4654 s.This research quantifies the angular performance variations of the ionic liquid electrospray thruster,offering valuable data to improve its design and operational reliability for precise propulsion and altitude control in satellite applications.展开更多
In order to meet the demand of CubeSats for low power and high-performance micro-propulsion system,a porous ionic liquid electrospray thruster prototype is developed in this study.1010 conical emitter arrays are fabri...In order to meet the demand of CubeSats for low power and high-performance micro-propulsion system,a porous ionic liquid electrospray thruster prototype is developed in this study.1010 conical emitter arrays are fabricated on an area of 3.24 cm^(2) by computer numerical control machining technology.The propellant is 1-ethyl-3-methylimidazolium tetrafluoroborate.The over-all dimension of the assembled prototype is 3 cm×3 cm×1 cm,with a total weight of about 15 g(with propellant).The performance of this prototype is tested under vacuum.The results show that it can work in the voltage range of±2.0 kV to±3.0 kV,and the maximum emission current and input power are about 355 lA and 1.12 W.Time of Flight(TOF)mass spectrometry results show that cationic monomers and dimers dominate the beam in positive mode,while a higher proportion of higher-order solvated ion clusters in negative mode.The maximum specific impulse is 2992 s in positive mode and 849 s in negative mode.The thrust is measured in two methods:one is calculated by TOF results and the other is directly measured by high-precision torsional thrust stand.The thrust(T)obtained by these two methods conforms to a certain scaling law with respect to the emis-sion current(I_(em))and the applied voltage(V_(app)),following the scale of T-Iem_(Vapp)^(0.5),and the thrust range is from 2.1 lN to 42.6 lN.Many thruster performance parameters are significantly different in positive and negative modes.We speculate that due to the higher solvation energy of the anion,more solvated ion clusters are formed rather than pure ions under the same electric field.It may help to improve thruster performance if porous materials with smaller pore sizes are used as reservoirs.Although there are still many problems,most of the performance parameters of ILET-3 are good,which can theoretically meet the requirements of CubeSats for micro-propulsion system.展开更多
基金co-supported by the National Key R&D Program of China(Nos.2020YFC2201103 and 2022YFB4601300)the National Natural Science Foundation of China(No.U22B20120)+1 种基金the Program of Beijing Engineering Research Center of Efficient and Green Aerospace Propulsion Technology,China(No.Lab ASP-2024-09)the Beijing Institute of Technology Research Fund Program for Young Scholars,China。
文摘Porous ionic liquid electrospray thrusters are the ideal propulsion technology for CubeSats because of their structural simplicity,high thrust accuracy and plume self-neutralization.The electrowetting technology can replenish the propellant for the emitter online,thus prolonging the lifetime of the thruster.In order to gain a deeper understanding of its operating characteristics,the changes in thruster performance before and after propellant replenishment deserve to be scrutinized.In this study,the performance changes of a porous electrowetting ionic liquid electrospray thruster are tested by voltage-current test and time-of-flight mass spectrometry over a long operating time.The experimental results show that asymmetric operation with a negative current less than positive current for a long period of time causes anions to compensate for the emission after accumulation at the emitter,resulting in a phenomenon that the negative current is much larger than positive current.The reason for the difference in emission characteristics between the positive and negative modes is that the plume in the positive mode is quite ionized while the plume in the negative mode contains liquid droplets.This study provides a reference for the selection of operating conditions for ionic liquid electrospray thrusters.
基金supported by the National Key R&D Program of China(Nos.2020YFC2201103 and 2022YFB4601300)National Natural Science Foundation of China(No.U22B20120)+1 种基金the Program of Beijing Engineering Research Center of Efficient and Green Aerospace Propulsion Technology(No.LabASP-2024-09)the Beijing Institute of Technology Research Fund Program for Young Scholars.
文摘The ionic liquid electrospray thruster is a microminiature thruster that can be applied on a micro or nano-satellite,and its highly energy-efficient,compact,modular system can be used for both main propulsion and altitude control.In this study,an ionic liquid electrospray thruster with a 100-tip emitter configuration is tested primarily to examine the difference in performance of the thruster at different angles with time-of-flight(TOF)mass spectrometry tests.In the experiment,it was measured that the half-angle of the thruster plume angle emission was in the range of−60 degrees to+65 degrees.Accordingly,the measurement range was set from−50 degrees to+50 degrees,with an interval of 10 degrees.Relative to the results of the 0 degree current curve,the positive mode is relatively homogeneous at all angles of the operating mode.In the negative mode,for n 2 ions,the negative angle region accounts for a larger proportion and the positive angle region accounts for a smaller proportion,which makes a significant difference to the specific impulse of the two regions.The range of the specific impulse at different angles is 3776-4401 s under the typical working condition of+2.5 kV.Under−2.5 kV,the range of the specific impulse at different angles is 3309-4654 s.This research quantifies the angular performance variations of the ionic liquid electrospray thruster,offering valuable data to improve its design and operational reliability for precise propulsion and altitude control in satellite applications.
基金supported by the National Key R&D Program of China(No.2020YFC2201103).
文摘In order to meet the demand of CubeSats for low power and high-performance micro-propulsion system,a porous ionic liquid electrospray thruster prototype is developed in this study.1010 conical emitter arrays are fabricated on an area of 3.24 cm^(2) by computer numerical control machining technology.The propellant is 1-ethyl-3-methylimidazolium tetrafluoroborate.The over-all dimension of the assembled prototype is 3 cm×3 cm×1 cm,with a total weight of about 15 g(with propellant).The performance of this prototype is tested under vacuum.The results show that it can work in the voltage range of±2.0 kV to±3.0 kV,and the maximum emission current and input power are about 355 lA and 1.12 W.Time of Flight(TOF)mass spectrometry results show that cationic monomers and dimers dominate the beam in positive mode,while a higher proportion of higher-order solvated ion clusters in negative mode.The maximum specific impulse is 2992 s in positive mode and 849 s in negative mode.The thrust is measured in two methods:one is calculated by TOF results and the other is directly measured by high-precision torsional thrust stand.The thrust(T)obtained by these two methods conforms to a certain scaling law with respect to the emis-sion current(I_(em))and the applied voltage(V_(app)),following the scale of T-Iem_(Vapp)^(0.5),and the thrust range is from 2.1 lN to 42.6 lN.Many thruster performance parameters are significantly different in positive and negative modes.We speculate that due to the higher solvation energy of the anion,more solvated ion clusters are formed rather than pure ions under the same electric field.It may help to improve thruster performance if porous materials with smaller pore sizes are used as reservoirs.Although there are still many problems,most of the performance parameters of ILET-3 are good,which can theoretically meet the requirements of CubeSats for micro-propulsion system.
