Ionic Liquid Electrospray Thrusters(ILETs)are well suited for micro-nano satellite applications due to their small size,low power consumption,and high specific impulse.However,the limited thrust of a single-emitter IL...Ionic Liquid Electrospray Thrusters(ILETs)are well suited for micro-nano satellite applications due to their small size,low power consumption,and high specific impulse.However,the limited thrust of a single-emitter ILET restricts its use in space missions.To optimize the performance of ILETs and make them suitable for a wider range of space missions,we designed a Circular-emitter ILET(CILET)to convert a one-dimensional(point)emission into a twodimensional(line)emission.The CILET can self-organize multiple Taylor cones simultaneously.The cones were photographed and the axial emission currents were measured under different voltage and pressure difference conditions with a CILET experimental system.The emission can be divided into two stable states and one unstable state based on the flow and current characteristics.The current in Stable state Ⅰ increases non-linearly with the voltage,while that in Stable state Ⅱ is nearly linear with respect to the voltage.The number of cones increases with the voltage in stable states,while the cones become short and crowded under high-voltage conditions.The variation law of the number of cones can be explained with the self-organization theory.The variation in the current exhibits a good correlation with the number of cones.This study demonstrates the feasibility of circular emitters and experimentally indicates that the emission current is improved by approximately two orders of magnitude compared to that of a single capillary.展开更多
The life of magnetically shielded Hall thrusters has not been fully studied.To investigate the life characteristics of magnetically shielded Hall thrusters,a life test of 8000 h was conducted on a 1.35 kW magnetically...The life of magnetically shielded Hall thrusters has not been fully studied.To investigate the life characteristics of magnetically shielded Hall thrusters,a life test of 8000 h was conducted on a 1.35 kW magnetically shielded Hall thruster for the first time.The thrust,specific impulse,efficiency,and other performance parameters were measured during the thruster’s life test,as well as the changes in the profile of the discharge channel wall.The patterns of changes in these parameters were summarized,and the effectiveness of magnetic shielding technology was verified.展开更多
Research has been carried out on a hybrid discharge ion thruster,aiming to combine the advantages of Direct Current(DC)discharge ion thrusters(known for their high thrust density and high power supply efficiency)with ...Research has been carried out on a hybrid discharge ion thruster,aiming to combine the advantages of Direct Current(DC)discharge ion thrusters(known for their high thrust density and high power supply efficiency)with microwave discharge ion thrusters(which do not require a hollow cathode and are capable of efficient ionization at low pressures).Comparative experiments with different anode structures and single-probe diagnostics revealed that applying a DC bias voltage created a new ionization zone based on microwave discharge.This DC bias increased the sheath potential of the screen grid and led to an elevation in electron temperature and plasma density.It is speculated that the reduced loss of high-energy electrons generated by microwave discharge at the screen grid is the primary reason for the enhanced discharge.By adding a DC bias of approximately 50 V to the microwave discharge,the screen grid current was doubled without a significant increase in discharge power consumption.Under appropriate bias voltages that consider minimizing ion sputtering,DC bias holds promise as a design approach to increase the extracted beam current in microwave ion thrusters.展开更多
Applied field magnetoplasmadynamic thrusters(AF-MPDTs), with their high specific impulse and considerable thrust, are increasingly favored for large-scale space missions. This paper presents the composition, functiona...Applied field magnetoplasmadynamic thrusters(AF-MPDTs), with their high specific impulse and considerable thrust, are increasingly favored for large-scale space missions. This paper presents the composition, functionality, and testing methods of a high-power electric propulsion performance testing system, along with the vacuum ignition test results of a 100 kW superconducting MPD thruster. The relationships between thruster efficiency, magnetic field strength, current,and mass flow rate are analyzed. For each combination of current and flow rate in an AF-MPDT, there is an optimal magnetic field strength where the thruster efficiency reaches its peak. Under conditions of 320 A current and 60 mg/s flow rate,the optimal magnetic field strength is 0.5 T, yielding the highest thruster efficiency of 71%.展开更多
Compared with the propulsion mode using the fluctuation or swing of fins,the water-jet propulsion of cephalopods has attracted much attention because of its high swimming speed.This paper introduces a squid-like under...Compared with the propulsion mode using the fluctuation or swing of fins,the water-jet propulsion of cephalopods has attracted much attention because of its high swimming speed.This paper introduces a squid-like underwater thruster based on an origami structure,which can realize water-jet propulsion by changing the shape of its origami structure.At the same time,it is combined with a soft vector nozzle driven by negative pressure for underwater steering.In addition,a triboelectric sensor(TES)is embedded in the origami structure to monitor the shape change of the thruster in real time.The kinematics model of the origami structure is established,and the dihedral angle B_(0)^(4),which can be used to characterize the unique shape of the thruster,is put forward.The dihedral angle B_(0)^(4)is monitored by the TES so that the shape change of the thruster can be feedback in real-time.Prototypes of the thruster and vector nozzle were fabricated,and the maximum error of TES in monitoring the shape of the thruster was less than 4.4%.At the same time,an underwater test platform was built to test the thruster’s propulsion performance and the vector nozzle’s deflection effect.展开更多
The deposition layer on the discharge channel wall of a Hall thruster after long-term operation occasionally detaches from the wall and interferes with the plasma inside the channel,resulting in current pulse and thre...The deposition layer on the discharge channel wall of a Hall thruster after long-term operation occasionally detaches from the wall and interferes with the plasma inside the channel,resulting in current pulse and threatening the power supply.To understand the generation mechanism of the current pulse,the interaction between the peeling material and the channel plasma was studied by the particle-in-cell and Monte Carlo collision(PIC/MCC)method.The plasma evolution and distribution in the Hall thruster channel when peeling material existed were simulated.Simulation results show that the peeling material changes the electron transportation and ionization,and the effects are related to the position of the peeling material.When the peeling material invades the zone where the ionization rate is originally the highest without peeling material,the ionization process is almost terminated.The ionization suppression by the peeling material will cause the propellant gas to refill the channel exit.As the peeling material moves away,gas discharge is induced near the channel exit,resulting in anode current pulse.展开更多
Robust numerical tools are essential for enabling the use of hybrid rocket engines(HREs)in future space applications.In this context,Computational Fluid Dynamics(CFD)transient simulations can be employed to analyse an...Robust numerical tools are essential for enabling the use of hybrid rocket engines(HREs)in future space applications.In this context,Computational Fluid Dynamics(CFD)transient simulations can be employed to analyse and predict relevant fluid dynamics phenomena within the thrust chamber of small-scale HREs.This work applies such techniques to investigate two unexpected behaviours observed in a 10 N-class hydrogen peroxide-based hybrid thruster:an uneven regression rate during High-Density Polyethylene(HDPE)and Acrylonitrile Butadiene Styrene(ABS)fuel tests,and non-negligible axial consumption in the ABS test case.The present study seeks to identify their fluid-dynamic origins by analysing key aspects of the thruster’s internal ballistics.The impact of recirculation zones and mixing on regression rates is quantified,as is the effect of grain heating on performance.Although already known in the present scientific literature,these phenomena prove to become particularly relevant for small-scale engines.Furthermore,the study demonstrates how appropriate numerical tools can replicate experimental findings,helping to foresee and mitigate undesirable behaviours in the design phases of future HRE propulsion systems.CFD results match the final HDPE grain geometry,reproducing the uneven port diameters with a maximum error below 9%.For ABS,axial regression is accurately captured,confirming the model’s reliability.Furthermore,average regression rates differ by only 1.60%and 1.20%for HDPE and ABS,respectively,while mass consumption is reproduced within 1.70%for HDPE and 3.01%for ABS.Overall,the results of the work demonstrate the reliability of the numerical approach adopted.This enriches the analysis capabilities devoted to 10 N-class engines,provides an additional tool for simulating the internal ballistics of small-scale hybrid thrusters,and integrates the existing literature with new insights into their fluid dynamics.展开更多
Inductive-pulsed plasma thruster is an in-space propulsion device that generates thrust by ionizing and accelerating plasma through pulsed electromagnetic field.In this paper,the correlation between plasma structure e...Inductive-pulsed plasma thruster is an in-space propulsion device that generates thrust by ionizing and accelerating plasma through pulsed electromagnetic field.In this paper,the correlation between plasma structure evolution and magnetic field permeability is studied using a B-dot probe array system,combing with high-speed camera and electrical parameter measurement.Further discussions explained the mechanism how the magnetic permeation characteristics affect the energy deposition between circuit and plasma.展开更多
The magnetoplasmadynamic thruster(MPDT) is characterized by its high specific impulse and substantial thrust density, making it a promising propulsion system for deep space exploration missions. In both laboratory exp...The magnetoplasmadynamic thruster(MPDT) is characterized by its high specific impulse and substantial thrust density, making it a promising propulsion system for deep space exploration missions. In both laboratory experiments and practical applications, cathode ablation has emerged as a critical concern. An optical diagnostic approach based on monochromatic radiation temperature measurement, utilizing plume emission spectra and the selection of an appropriate test band, has been successfully employed. This method provides an accurate temperature distribution across the cathode surface, offering a novel testing technique for the optimization and evaluation of magnetic plasma thruster designs.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
To address the future application requirements of carbon-based material grids for ion thrusters characterized by high thrust,elevated specific impulse,and extended operational life,research was conducted using the LIP...To address the future application requirements of carbon-based material grids for ion thrusters characterized by high thrust,elevated specific impulse,and extended operational life,research was conducted using the LIPS-100 ion thruster developed by the Lanzhou Institute of Physics.This study focused on small-diameter configurations of carbon-carbon composite material grids.Successful development was achieved for both a 10 cm split carbon-carbon planar grid and an integrated carbon-carbon convex grid component.Performance variations among different configurations were investigated through extensive performance tests across the wide-range from 1 to 25 mN,as well as 200 h lifespan assessments under typical conditions at 20 mN.The results indicate that the two configurations of the carbon-carbon grid can achieve stable operation across the broad range of 1-20 mN,with beam current fluctuations ranging from 368 to 379 mA and accel grid current fluctuations between 1.58 and 1.81 mA.Furthermore,the key performance parameters of these grids were comparable to those of the traditional molybdenum grids.Under conditions of high thrust and power,the carbon-carbon grid demonstrated a significant reduction in the intercepted current at the accel grid.In comparison to the split carbon-carbon planar grid,the weight of the integrated carbon-carbon convex composite grid was reduced by 17.5%,the anode voltage decreased by approximately 2.4%-8.6%,and the cathode keeper voltage was reduced by approximately 3.5%-12.4%.It can be concluded that the integrated carbon-carbon convex grid offers distinct advantages in terms of hot-state structural stability,suppression of grid etching rates,and enhancement of thruster discharge efficiency.展开更多
In a pulsed plasma thruster,the voltage distribution between the electrodes is a key factor that influences the ionization process.However,few researchers have conducted in-depth studies of this phenomenon in the past...In a pulsed plasma thruster,the voltage distribution between the electrodes is a key factor that influences the ionization process.However,few researchers have conducted in-depth studies of this phenomenon in the past.Reported here are measurements of the voltage distribution between the plates of a parallel-plate pulsed plasma thruster under different discharge voltages,based on which the variations in the total circuit inductance and resistance as well as those between the plates are calculated.The results show that the time-averaged voltage across the plates accounts for 28.7%-50.4%of the capacitor voltage.As the capacitor initial voltage increases from 1250 V to 2000 V,the voltage across the plates rises,but its proportion relative to the capacitor voltage decreases.For every 250 V increase in the capacitor initial voltage,the average voltage proportion across the plates decreases by approximately 2%-3%.Additionally,the voltage proportion decreases gradually from the end near the propellant outward.The voltage distribution ratio between the plates is correlated with the proportions of the resistance and inductance between the plates relative to the total circuit.展开更多
Exploring solid propellants for electric thrusters can simplify the propellant storage and supply units in propulsion systems.In this study,polytetrafluoroethylene(PTFE),commonly used as a propellant in pulsed plasma ...Exploring solid propellants for electric thrusters can simplify the propellant storage and supply units in propulsion systems.In this study,polytetrafluoroethylene(PTFE),commonly used as a propellant in pulsed plasma thrusters,was embedded in the discharge chamber of a radio frequency ion thruster(RIT-4)to investigate the performance of an ablation-type RIT.Experimental results indicate that PTFE can decompose and ionize stably under plasma ablation within the discharge chamber,producing-C-F-and F-ion clusters that form a stable plasma.By adjusting the length of the PTFE propellant,it was observed that its decomposition rate influences the ion beam current of the thruster.Compared with xenon,PTFE generates an ion plume with a larger divergence angle,ranging from 16.05°to 22.74°at an ion beam current of 25 mA,with a floating potential distribution of 8‒56 V.Assuming that the proportion of neutral gas in the vacuum chamber matches the ion species ratio in the ion plume,thrust,specific impulse and efficiency parameters were calculated for the RIT-4 with embedded PTFE.Under 50 W RF power,the thrust was approximately 1.02 mN,the specific impulse was around 1236 s and the power-to-thrust ratio was approximately 93.14 W/mN.All results indicate that PTFE is a viable propellant for RIT,but the key is to control the rate of decomposition.展开更多
The field-reversed configuration(FRC)plasma thruster driven by rotating magnetic field(RMF),abbreviated as the RMF-FRC thruster,is a new type of electric propulsion technology that is expected to accelerate the deep s...The field-reversed configuration(FRC)plasma thruster driven by rotating magnetic field(RMF),abbreviated as the RMF-FRC thruster,is a new type of electric propulsion technology that is expected to accelerate the deep space exploration.An experimental prototype,including diagnostic devices,was designed and constructed based on the principles of the RMF-FRC thruster,with an RMF frequency of 210 kHz and a maximum peak current of 2 kA.Under the rated operating conditions,the initial plasma density was measured to be 5×10^(17)m^(-3),and increased to 2.2×10^(19)m^(-3)after the action of RMF.The coupling efficiency of RMF was about 53%,and the plasma current reached 1.9 kA.The axial magnetic field changed in reverse by 155 Gauss,successfully reversing the bias magnetic field of 60 Gauss,which verifies the formation of FRC plasma.After optimization research,it was found that when the bias magnetic field is 100 Gauss,the axial magnetic field reverse variation caused by FRC is the highest at 164 Gauss.The experimental results are discussed and strategies are proposed to improve the performance of the prototype.展开更多
An optical emission spectroscopy(OES)method with a non-invasive measurement capability,without inducing disturbance to the discharge,represents an effective method for material monitoring.However,when the OES method i...An optical emission spectroscopy(OES)method with a non-invasive measurement capability,without inducing disturbance to the discharge,represents an effective method for material monitoring.However,when the OES method is employed to monitor the trace erosion product within the ceramic channel of a Hall thruster,it becomes challenging to distinguish between signal and noise.In this study,we propose a model filtering method based on the signal characteristics of the Hall thruster plume spectrometer.This method integrates the slit imaging and spectral resolution features of the spectrometer.Employing this method,we extract the spectral signals of the erosion product and working gas from the Hall thruster under different operating conditions.The results indicate that our new method performs comparably to the traditional method without model filtering when extracting atom signals from strong xenon working gas.However,for trace amounts of the erosion product,our approach significantly enhances the signal-to-noise ratio(SNR),enabling the identification of extremely weak spectral signals even under low mass flow rate and low-voltage conditions.We obtain boron atom concentration of 3.91×10^(-3) kg/m^(3) at a mass flow rate of 4×10^(-7) kg/s and voltage of 200 V while monitoring a wider range of thruster operating conditions.The new method proposed in this study is suitable for monitoring other low-concentration elements,making it valuable for materials processing,environmental monitoring and space propulsion applications.展开更多
The decomposition and combustion characteristics of ammonium dinitramide (ADN) based non-toxic aerospace propellant are analytically studied to determine the effects of catalytic bed structure (slenderness ratio) and ...The decomposition and combustion characteristics of ammonium dinitramide (ADN) based non-toxic aerospace propellant are analytically studied to determine the effects of catalytic bed structure (slenderness ratio) and operation parameters (mass fraction ratio of ADN/CH3OH) on the general performance within the ADN-based thruster. In the present research, the non-equilibrium temperature model is utilized to describe the heat transfer characteristics between the fluid phase and solid phase in the fixed bed. We determined the fluid resistance characteristics in the catalytic bed by experiments involving the method of pressure-mass. We have done the simulation study based on the available results in the literature and found the complex physical and chemical processes within the ADN thruster. Furthermore, an optimized catalytic bed slenderness ratio was observed w让h a value of 1.75 and the mass fraction ratio of 5.73 significantly influenced the propellant performance. These results could serve as a reference to explore the combustion characteristics within the thruster and the preparation of future propellants.展开更多
The transport processes of plasmas in grid systems of krypton（Kr） ion thrusters at different acceleration voltages were simulated with a 3 D-PIC model, and the result was compared with xenon（Xe） ion thrusters. The...The transport processes of plasmas in grid systems of krypton（Kr） ion thrusters at different acceleration voltages were simulated with a 3 D-PIC model, and the result was compared with xenon（Xe） ion thrusters. The variation of the screen grid transparency, the accelerator grid current ratio and the divergence loss were explored. It is found that the screen grid transparency increases with the acceleration voltage and decreases with the beam current, while the accelerator grid current ratio and divergence loss decrease first and then increase with the beam current. This result is the same with Xe ion thrusters. Simulation results also show that Kr ion thrusters have more advantages than Xe ion thrusters, such as higher screen grid transparency, smaller accelerator grid current ratio, larger cut-off current threshold, and better divergence loss characteristic. These advantages mean that Kr ion thrusters have the ability of operating in a wide range of current. Through comprehensive analyses, it can be concluded that using Kr as propellant is very suitable for a multimode ion thruster design.展开更多
Ion optics is a critical component of ion thrusters. A two-dimensional axisymmetric model is developed to study the characteristics of three-grid electron cyclotron resonance ion thruster optics. The code is based on ...Ion optics is a critical component of ion thrusters. A two-dimensional axisymmetric model is developed to study the characteristics of three-grid electron cyclotron resonance ion thruster optics. The code is based on a particle-in-cell combined with the Monte Carlo collision method to simulate ion dynamics and charge-exchange processes in the grid region. The simulation results show that the mode can give a reasonable estimate of the physics characteristics of the ion optics. The design of the ion optics satisfies the requirement of preventing electron backstreaming. Charge-exchange ions can cause damage to the grids, especially to the accelerator grid. ＇Barrel＇ erosion can increase the accelerator grid aperture radius at a rate of 1.91~ 10-11 m/s, while the decelerator grid plays an important role in reducing ＇pits-and-grooves＇ erosion.展开更多
Ion thruster plumes from a multi-thruster array of different working configurations are simulated by a hybrid fluid-particle software. The particle in cell method is employed to model the transports of ions. The direc...Ion thruster plumes from a multi-thruster array of different working configurations are simulated by a hybrid fluid-particle software. The particle in cell method is employed to model the transports of ions. The direct simulation Monte Carlo method is used to model momentum and charge exchange （CEX） collisions. The software is based on unstructured grids which make it easy to handle with complex geometry. The results of chamber simulation are compared with experimental data in ion current density and number density, which show good agreements. The maximum difference of current density along the thruster centerline is less than 9.30%. The interaction effects of plumes when multiple thrusters are operating in vacuum are predicted. Distributions of single charged xenon ions are significantly different in the near-field plume flow, however, merge into one in the far downstream region. Moreover, the interaction effect on the spatial distribution of CEX xenon ions is displayed as well.展开更多
基金co-supported by the National Key R&D Program of China(No.2020YFC2201001)the Shenzhen Science and Technology Program,China(No.20210623091808026)。
文摘Ionic Liquid Electrospray Thrusters(ILETs)are well suited for micro-nano satellite applications due to their small size,low power consumption,and high specific impulse.However,the limited thrust of a single-emitter ILET restricts its use in space missions.To optimize the performance of ILETs and make them suitable for a wider range of space missions,we designed a Circular-emitter ILET(CILET)to convert a one-dimensional(point)emission into a twodimensional(line)emission.The CILET can self-organize multiple Taylor cones simultaneously.The cones were photographed and the axial emission currents were measured under different voltage and pressure difference conditions with a CILET experimental system.The emission can be divided into two stable states and one unstable state based on the flow and current characteristics.The current in Stable state Ⅰ increases non-linearly with the voltage,while that in Stable state Ⅱ is nearly linear with respect to the voltage.The number of cones increases with the voltage in stable states,while the cones become short and crowded under high-voltage conditions.The variation law of the number of cones can be explained with the self-organization theory.The variation in the current exhibits a good correlation with the number of cones.This study demonstrates the feasibility of circular emitters and experimentally indicates that the emission current is improved by approximately two orders of magnitude compared to that of a single capillary.
基金supported by National Natural Science Foundation of China(No.U23B20152).
文摘The life of magnetically shielded Hall thrusters has not been fully studied.To investigate the life characteristics of magnetically shielded Hall thrusters,a life test of 8000 h was conducted on a 1.35 kW magnetically shielded Hall thruster for the first time.The thrust,specific impulse,efficiency,and other performance parameters were measured during the thruster’s life test,as well as the changes in the profile of the discharge channel wall.The patterns of changes in these parameters were summarized,and the effectiveness of magnetic shielding technology was verified.
基金National Key R&D Program of China(No.2020YFC2201000).
文摘Research has been carried out on a hybrid discharge ion thruster,aiming to combine the advantages of Direct Current(DC)discharge ion thrusters(known for their high thrust density and high power supply efficiency)with microwave discharge ion thrusters(which do not require a hollow cathode and are capable of efficient ionization at low pressures).Comparative experiments with different anode structures and single-probe diagnostics revealed that applying a DC bias voltage created a new ionization zone based on microwave discharge.This DC bias increased the sheath potential of the screen grid and led to an elevation in electron temperature and plasma density.It is speculated that the reduced loss of high-energy electrons generated by microwave discharge at the screen grid is the primary reason for the enhanced discharge.By adding a DC bias of approximately 50 V to the microwave discharge,the screen grid current was doubled without a significant increase in discharge power consumption.Under appropriate bias voltages that consider minimizing ion sputtering,DC bias holds promise as a design approach to increase the extracted beam current in microwave ion thrusters.
文摘Applied field magnetoplasmadynamic thrusters(AF-MPDTs), with their high specific impulse and considerable thrust, are increasingly favored for large-scale space missions. This paper presents the composition, functionality, and testing methods of a high-power electric propulsion performance testing system, along with the vacuum ignition test results of a 100 kW superconducting MPD thruster. The relationships between thruster efficiency, magnetic field strength, current,and mass flow rate are analyzed. For each combination of current and flow rate in an AF-MPDT, there is an optimal magnetic field strength where the thruster efficiency reaches its peak. Under conditions of 320 A current and 60 mg/s flow rate,the optimal magnetic field strength is 0.5 T, yielding the highest thruster efficiency of 71%.
文摘Compared with the propulsion mode using the fluctuation or swing of fins,the water-jet propulsion of cephalopods has attracted much attention because of its high swimming speed.This paper introduces a squid-like underwater thruster based on an origami structure,which can realize water-jet propulsion by changing the shape of its origami structure.At the same time,it is combined with a soft vector nozzle driven by negative pressure for underwater steering.In addition,a triboelectric sensor(TES)is embedded in the origami structure to monitor the shape change of the thruster in real time.The kinematics model of the origami structure is established,and the dihedral angle B_(0)^(4),which can be used to characterize the unique shape of the thruster,is put forward.The dihedral angle B_(0)^(4)is monitored by the TES so that the shape change of the thruster can be feedback in real-time.Prototypes of the thruster and vector nozzle were fabricated,and the maximum error of TES in monitoring the shape of the thruster was less than 4.4%.At the same time,an underwater test platform was built to test the thruster’s propulsion performance and the vector nozzle’s deflection effect.
基金supported by National Natural Science Foundation of China(No.U23B20152).
文摘The deposition layer on the discharge channel wall of a Hall thruster after long-term operation occasionally detaches from the wall and interferes with the plasma inside the channel,resulting in current pulse and threatening the power supply.To understand the generation mechanism of the current pulse,the interaction between the peeling material and the channel plasma was studied by the particle-in-cell and Monte Carlo collision(PIC/MCC)method.The plasma evolution and distribution in the Hall thruster channel when peeling material existed were simulated.Simulation results show that the peeling material changes the electron transportation and ionization,and the effects are related to the position of the peeling material.When the peeling material invades the zone where the ionization rate is originally the highest without peeling material,the ionization process is almost terminated.The ionization suppression by the peeling material will cause the propellant gas to refill the channel exit.As the peeling material moves away,gas discharge is induced near the channel exit,resulting in anode current pulse.
文摘Robust numerical tools are essential for enabling the use of hybrid rocket engines(HREs)in future space applications.In this context,Computational Fluid Dynamics(CFD)transient simulations can be employed to analyse and predict relevant fluid dynamics phenomena within the thrust chamber of small-scale HREs.This work applies such techniques to investigate two unexpected behaviours observed in a 10 N-class hydrogen peroxide-based hybrid thruster:an uneven regression rate during High-Density Polyethylene(HDPE)and Acrylonitrile Butadiene Styrene(ABS)fuel tests,and non-negligible axial consumption in the ABS test case.The present study seeks to identify their fluid-dynamic origins by analysing key aspects of the thruster’s internal ballistics.The impact of recirculation zones and mixing on regression rates is quantified,as is the effect of grain heating on performance.Although already known in the present scientific literature,these phenomena prove to become particularly relevant for small-scale engines.Furthermore,the study demonstrates how appropriate numerical tools can replicate experimental findings,helping to foresee and mitigate undesirable behaviours in the design phases of future HRE propulsion systems.CFD results match the final HDPE grain geometry,reproducing the uneven port diameters with a maximum error below 9%.For ABS,axial regression is accurately captured,confirming the model’s reliability.Furthermore,average regression rates differ by only 1.60%and 1.20%for HDPE and ABS,respectively,while mass consumption is reproduced within 1.70%for HDPE and 3.01%for ABS.Overall,the results of the work demonstrate the reliability of the numerical approach adopted.This enriches the analysis capabilities devoted to 10 N-class engines,provides an additional tool for simulating the internal ballistics of small-scale hybrid thrusters,and integrates the existing literature with new insights into their fluid dynamics.
基金Project supported by the Science Fund for Creative Research Groups of the National Natural Science Foundation of China(Grant No.T2221002)the Young Scientists Fund of the National Natural Science Foundation of China(Grant No.12305286)。
文摘Inductive-pulsed plasma thruster is an in-space propulsion device that generates thrust by ionizing and accelerating plasma through pulsed electromagnetic field.In this paper,the correlation between plasma structure evolution and magnetic field permeability is studied using a B-dot probe array system,combing with high-speed camera and electrical parameter measurement.Further discussions explained the mechanism how the magnetic permeation characteristics affect the energy deposition between circuit and plasma.
文摘The magnetoplasmadynamic thruster(MPDT) is characterized by its high specific impulse and substantial thrust density, making it a promising propulsion system for deep space exploration missions. In both laboratory experiments and practical applications, cathode ablation has emerged as a critical concern. An optical diagnostic approach based on monochromatic radiation temperature measurement, utilizing plume emission spectra and the selection of an appropriate test band, has been successfully employed. This method provides an accurate temperature distribution across the cathode surface, offering a novel testing technique for the optimization and evaluation of magnetic plasma thruster designs.
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National Key R&D Program of China(No.2022YFB3403500)the Science and Technology Program of Gansu Province(No.22JR5RA784).
文摘To address the future application requirements of carbon-based material grids for ion thrusters characterized by high thrust,elevated specific impulse,and extended operational life,research was conducted using the LIPS-100 ion thruster developed by the Lanzhou Institute of Physics.This study focused on small-diameter configurations of carbon-carbon composite material grids.Successful development was achieved for both a 10 cm split carbon-carbon planar grid and an integrated carbon-carbon convex grid component.Performance variations among different configurations were investigated through extensive performance tests across the wide-range from 1 to 25 mN,as well as 200 h lifespan assessments under typical conditions at 20 mN.The results indicate that the two configurations of the carbon-carbon grid can achieve stable operation across the broad range of 1-20 mN,with beam current fluctuations ranging from 368 to 379 mA and accel grid current fluctuations between 1.58 and 1.81 mA.Furthermore,the key performance parameters of these grids were comparable to those of the traditional molybdenum grids.Under conditions of high thrust and power,the carbon-carbon grid demonstrated a significant reduction in the intercepted current at the accel grid.In comparison to the split carbon-carbon planar grid,the weight of the integrated carbon-carbon convex composite grid was reduced by 17.5%,the anode voltage decreased by approximately 2.4%-8.6%,and the cathode keeper voltage was reduced by approximately 3.5%-12.4%.It can be concluded that the integrated carbon-carbon convex grid offers distinct advantages in terms of hot-state structural stability,suppression of grid etching rates,and enhancement of thruster discharge efficiency.
基金supported by the Beijing Natural Science Foundation(No.QY24166).
文摘In a pulsed plasma thruster,the voltage distribution between the electrodes is a key factor that influences the ionization process.However,few researchers have conducted in-depth studies of this phenomenon in the past.Reported here are measurements of the voltage distribution between the plates of a parallel-plate pulsed plasma thruster under different discharge voltages,based on which the variations in the total circuit inductance and resistance as well as those between the plates are calculated.The results show that the time-averaged voltage across the plates accounts for 28.7%-50.4%of the capacitor voltage.As the capacitor initial voltage increases from 1250 V to 2000 V,the voltage across the plates rises,but its proportion relative to the capacitor voltage decreases.For every 250 V increase in the capacitor initial voltage,the average voltage proportion across the plates decreases by approximately 2%-3%.Additionally,the voltage proportion decreases gradually from the end near the propellant outward.The voltage distribution ratio between the plates is correlated with the proportions of the resistance and inductance between the plates relative to the total circuit.
基金supported by the National Key R&D Program of China(No.2021YFC2202800)the Youth Innovation Promotion Association CAS(No.2023022)Institute of Mechanics Outstanding Young Talent Training Program(No.E1Z1030201).
文摘Exploring solid propellants for electric thrusters can simplify the propellant storage and supply units in propulsion systems.In this study,polytetrafluoroethylene(PTFE),commonly used as a propellant in pulsed plasma thrusters,was embedded in the discharge chamber of a radio frequency ion thruster(RIT-4)to investigate the performance of an ablation-type RIT.Experimental results indicate that PTFE can decompose and ionize stably under plasma ablation within the discharge chamber,producing-C-F-and F-ion clusters that form a stable plasma.By adjusting the length of the PTFE propellant,it was observed that its decomposition rate influences the ion beam current of the thruster.Compared with xenon,PTFE generates an ion plume with a larger divergence angle,ranging from 16.05°to 22.74°at an ion beam current of 25 mA,with a floating potential distribution of 8‒56 V.Assuming that the proportion of neutral gas in the vacuum chamber matches the ion species ratio in the ion plume,thrust,specific impulse and efficiency parameters were calculated for the RIT-4 with embedded PTFE.Under 50 W RF power,the thrust was approximately 1.02 mN,the specific impulse was around 1236 s and the power-to-thrust ratio was approximately 93.14 W/mN.All results indicate that PTFE is a viable propellant for RIT,but the key is to control the rate of decomposition.
基金supported by National Natural Science Foundation of China (NSFC) (Nos.62201217 and 51821005)。
文摘The field-reversed configuration(FRC)plasma thruster driven by rotating magnetic field(RMF),abbreviated as the RMF-FRC thruster,is a new type of electric propulsion technology that is expected to accelerate the deep space exploration.An experimental prototype,including diagnostic devices,was designed and constructed based on the principles of the RMF-FRC thruster,with an RMF frequency of 210 kHz and a maximum peak current of 2 kA.Under the rated operating conditions,the initial plasma density was measured to be 5×10^(17)m^(-3),and increased to 2.2×10^(19)m^(-3)after the action of RMF.The coupling efficiency of RMF was about 53%,and the plasma current reached 1.9 kA.The axial magnetic field changed in reverse by 155 Gauss,successfully reversing the bias magnetic field of 60 Gauss,which verifies the formation of FRC plasma.After optimization research,it was found that when the bias magnetic field is 100 Gauss,the axial magnetic field reverse variation caused by FRC is the highest at 164 Gauss.The experimental results are discussed and strategies are proposed to improve the performance of the prototype.
基金financially supported by National Natural Science Foundation of China(No.U22B2094)。
文摘An optical emission spectroscopy(OES)method with a non-invasive measurement capability,without inducing disturbance to the discharge,represents an effective method for material monitoring.However,when the OES method is employed to monitor the trace erosion product within the ceramic channel of a Hall thruster,it becomes challenging to distinguish between signal and noise.In this study,we propose a model filtering method based on the signal characteristics of the Hall thruster plume spectrometer.This method integrates the slit imaging and spectral resolution features of the spectrometer.Employing this method,we extract the spectral signals of the erosion product and working gas from the Hall thruster under different operating conditions.The results indicate that our new method performs comparably to the traditional method without model filtering when extracting atom signals from strong xenon working gas.However,for trace amounts of the erosion product,our approach significantly enhances the signal-to-noise ratio(SNR),enabling the identification of extremely weak spectral signals even under low mass flow rate and low-voltage conditions.We obtain boron atom concentration of 3.91×10^(-3) kg/m^(3) at a mass flow rate of 4×10^(-7) kg/s and voltage of 200 V while monitoring a wider range of thruster operating conditions.The new method proposed in this study is suitable for monitoring other low-concentration elements,making it valuable for materials processing,environmental monitoring and space propulsion applications.
文摘The decomposition and combustion characteristics of ammonium dinitramide (ADN) based non-toxic aerospace propellant are analytically studied to determine the effects of catalytic bed structure (slenderness ratio) and operation parameters (mass fraction ratio of ADN/CH3OH) on the general performance within the ADN-based thruster. In the present research, the non-equilibrium temperature model is utilized to describe the heat transfer characteristics between the fluid phase and solid phase in the fixed bed. We determined the fluid resistance characteristics in the catalytic bed by experiments involving the method of pressure-mass. We have done the simulation study based on the available results in the literature and found the complex physical and chemical processes within the ADN thruster. Furthermore, an optimized catalytic bed slenderness ratio was observed w让h a value of 1.75 and the mass fraction ratio of 5.73 significantly influenced the propellant performance. These results could serve as a reference to explore the combustion characteristics within the thruster and the preparation of future propellants.
基金co-supported by the National Natural Science Foundation of China (No. 11675040)the Fundamental Research Funds for the Central Universities of China (Nos. 3102014KYJD005 and 1191329723)
文摘The transport processes of plasmas in grid systems of krypton（Kr） ion thrusters at different acceleration voltages were simulated with a 3 D-PIC model, and the result was compared with xenon（Xe） ion thrusters. The variation of the screen grid transparency, the accelerator grid current ratio and the divergence loss were explored. It is found that the screen grid transparency increases with the acceleration voltage and decreases with the beam current, while the accelerator grid current ratio and divergence loss decrease first and then increase with the beam current. This result is the same with Xe ion thrusters. Simulation results also show that Kr ion thrusters have more advantages than Xe ion thrusters, such as higher screen grid transparency, smaller accelerator grid current ratio, larger cut-off current threshold, and better divergence loss characteristic. These advantages mean that Kr ion thrusters have the ability of operating in a wide range of current. Through comprehensive analyses, it can be concluded that using Kr as propellant is very suitable for a multimode ion thruster design.
文摘Ion optics is a critical component of ion thrusters. A two-dimensional axisymmetric model is developed to study the characteristics of three-grid electron cyclotron resonance ion thruster optics. The code is based on a particle-in-cell combined with the Monte Carlo collision method to simulate ion dynamics and charge-exchange processes in the grid region. The simulation results show that the mode can give a reasonable estimate of the physics characteristics of the ion optics. The design of the ion optics satisfies the requirement of preventing electron backstreaming. Charge-exchange ions can cause damage to the grids, especially to the accelerator grid. ＇Barrel＇ erosion can increase the accelerator grid aperture radius at a rate of 1.91~ 10-11 m/s, while the decelerator grid plays an important role in reducing ＇pits-and-grooves＇ erosion.
文摘Ion thruster plumes from a multi-thruster array of different working configurations are simulated by a hybrid fluid-particle software. The particle in cell method is employed to model the transports of ions. The direct simulation Monte Carlo method is used to model momentum and charge exchange （CEX） collisions. The software is based on unstructured grids which make it easy to handle with complex geometry. The results of chamber simulation are compared with experimental data in ion current density and number density, which show good agreements. The maximum difference of current density along the thruster centerline is less than 9.30%. The interaction effects of plumes when multiple thrusters are operating in vacuum are predicted. Distributions of single charged xenon ions are significantly different in the near-field plume flow, however, merge into one in the far downstream region. Moreover, the interaction effect on the spatial distribution of CEX xenon ions is displayed as well.
