CN111965232B - Electric spray on-orbit detection method of colloid electric propulsion system and application thereof - Google Patents
Electric spray on-orbit detection method of colloid electric propulsion system and application thereof Download PDFInfo
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- CN111965232B CN111965232B CN202010705750.4A CN202010705750A CN111965232B CN 111965232 B CN111965232 B CN 111965232B CN 202010705750 A CN202010705750 A CN 202010705750A CN 111965232 B CN111965232 B CN 111965232B
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Abstract
The invention belongs to the field of application of colloid electric propulsion systems, and particularly relates to an electric spray on-track detection method of a colloid electric propulsion system and application thereof, wherein the method comprises the following steps: when the electric spray emitted by the colloid electric propulsion system on the track flies according to the emission direction of the electric spray, external force is applied to the electric spray, so that part of the flight direction of the electric spray deflects; a good conductor electrode is arranged in the deflected flying direction, and when part of the electrospray flies to impact the good conductor electrode, a current signal generated by the impact is collected until the signal disappears; and processing the current signal to obtain the physical characteristics of the electrospray, and completing the on-track detection of the electrospray. The invention realizes the deflection sampling of the flight electric spray based on external force and the physical characteristic detection of the electric spray based on current signals so as to comprehensively analyze the performance of the electric propulsion system. Only a very small part of electrospray is extracted for inspection during electrospray sampling, the flight process of most electrospray in the normal emission direction is not influenced, and the continuous thrust output capability of a propulsion system can be ensured.
Description
Technical Field
The invention belongs to the field of application of colloid electric propulsion systems, and particularly relates to an electric spray on-track detection method of a colloid electric propulsion system and application thereof.
Background
The colloid electric propulsion technology is a novel space electric propulsion technology and has the characteristics of low thrust lower limit, large adjustable range, high adjustment precision, low noise and simpler system structure. The working medium of the colloid electric propeller is a molten-state ionic liquid at normal temperature, the ionic liquid is conveyed to the front end of the emission structure through a flow control system, and under the action of high voltage, the ionic liquid is emitted at a high speed through the physical process of cone jet flow-jet flow atomization-electrospray electrostatic acceleration-jet, and thrust in opposite directions is generated. The method mainly comprises two application scenes of the existing colloid electric propulsion technology, wherein one of the two application scenes is that the colloid electric propulsion technology is used as a mechanical compensation execution device to serve the drag-free control of a high-precision space experiment satellite by utilizing the characteristics of low thrust lower limit and high resolution of the colloid electric propulsion technology; in addition, the colloid electric propeller with improved emission efficiency has important application prospects in the fields of attitude regulation and control of micro-nano satellites, orbit maintenance/change and deep space exploration.
At present, the performance characterization of the colloid electric propeller is divided into two technical routes, namely a ground route and an on-orbit route. For ground characterization, a thrust measuring device such as a torsional pendulum and a simple pendulum can be used for directly measuring the thrust magnitude of the propeller, the thrust adjusting resolution and the thrust noise performance, for example, the method for measuring the weak thrust of the propeller by using the torsional pendulum is proposed in patent CN 103335769B; direct observation of propeller-emitted Electrospray can be performed using microscopy to obtain performance of the propulsion system, such as the experimental setup and method reported in the articles Electrospray-State and Transient Emission Behavior; the energy, flow, composition, and divergence angle of high-speed flight electrospray can be characterized using a time-of-flight mass spectrometer, such as the experimental apparatus and methods reported in the paper Electric-Field-Induced Ion evolution from electronic Liquid. For the colloid electric propeller working in the orbit, a satellite-borne inertial sensor can also be used for measuring the real-time thrust performance of the propeller, and the current and voltage information of each part of the propeller is monitored in real time for judging the system working condition of the propeller, such as the on-orbit measuring device and technology mentioned in the paper Experimental results from the ST7 mission on LISA Pathfinder.
However, colloidal thrusters suffer from instability when fired continuously in orbit but are difficult to diagnose in time. The stable emission of the colloid propeller depends on the dynamic coupling process of electric field force and surface tension, and the stability of the coupling process is related to a plurality of variables, including working medium viscosity, matching of transport flow and voltage, electric field distribution and the like. And when the propeller runs on the track, the influences of environmental factors such as temperature fluctuation, mechanical vibration, electromagnetic fluctuation and the like, and the influences of flow fluctuation, voltage output fluctuation, mechanical structure loss and the like generated after the propeller works for a long time are all disturbed in the coupling balance process of electric field force and fluid force, so that the electrospray emission cannot be in a stable state all the time. In the unstable process of the jet flow of the cone jet flow broken into the electrospray, the instability of the jet flow enhances the transverse unstable effect of the jet flow, and finally shows that the divergence angle of the electrospray is increased, so that the electrospray flying at high speed bombards a propeller structure to cause mechanical damage, chemical corrosion and short circuit, the service life of the system is seriously influenced, and even the system directly fails. Moreover, the electron spray bombardment electrode causes the emission efficiency to be reduced, so that the output thrust under the same flow and voltage is reduced, and in order to ensure the stable output of the thrust, the propeller control system must increase the emission voltage and increase the electron spray injection rate, but the instability degree is easily increased in the process, the electron spray divergence angle is further enlarged, the destructive power of the electron spray bombardment is increased, and a vicious circle is formed. When the colloid propulsion system runs in orbit, the instability phenomenon is only reflected on weak thrust fluctuation detected by the satellite-borne accelerometer, and the current/voltage characteristic of the propulsion system has no obvious change, so that the identification and diagnosis of the electrospray instability phenomenon are extremely difficult. At present, the problem can be overcome by the electrospray on-track detection technology of the colloid propulsion system, so that the colloid propulsion system is practical and has great risks.
Disclosure of Invention
The invention provides an electric spray on-track detection method of a colloid electric propulsion system and application thereof, which are used for solving the technical problem that the existing electric spray on-track detection method of the colloid electric propulsion system is difficult to be used for diagnosing the performance and the state of the system in time.
The technical scheme for solving the technical problems is as follows: an electrospray in-orbit detection method for a colloidal electric propulsion system, comprising:
when the electric spray emitted by the colloid electric propulsion system on the track flies according to the emission direction of the electric spray, applying external force to the electric spray to deflect the flying direction of part of the electric spray;
a good conductor electrode is arranged in the deflected flight direction, and when the partial electrospray flies to impact the good conductor electrode, a current signal generated by the impact is collected until the signal disappears;
and processing the current signal to obtain the physical characteristics of the electrospray, and completing the on-track detection of the electrospray.
The invention has the beneficial effects that: the invention realizes deflection sampling of flight electric spray based on external force, realizes physical characteristic detection of electric spray based on flight time mass spectrometry, is suitable for two colloid electric propulsion system working modes of electric spray continuous injection and electric spray pulse injection, further can be matched with the existing performance detection technology for use, so as to comprehensively analyze the performance of the electric propulsion system, represent thrust, specific impulse, emission efficiency of the in-orbit colloid electric propulsion system and state information whether the system is unstable or not, and has important significance for high-efficiency application of the colloid electric propulsion system. Particularly, the invention provides a strategy idea of sampling electrospray, only extracts a very small part of electrospray for inspection, does not influence the flight process of most electrospray in the normal emission direction, and can ensure the continuous thrust output capability of a propulsion system.
On the basis of the technical scheme, the invention can be further improved as follows.
Further, the external force is applied to the electrospray in the following implementation mode:
and applying a pulse electric field in a direction perpendicular to the emission direction by using a deflection electrode so as to change the flight direction of part of the electrospray under the action of electrostatic force.
The invention has the further beneficial effects that: by utilizing the pulse voltage, the flight direction of the electrospray flying through the deflection electrode during the period from the voltage starting to the voltage closing is deflected, so that the electrospray emitted by the colloid electric propulsion system is sampled, and the device has a simple structure and strong operability. Wherein the magnitude of the applied pulse voltage amplitude can be set according to the actually required deflection angle.
Further, the duration of application of the pulsed electric field<10-6s
The invention has the further beneficial effects that: due to very short duration of time (<10-6s) so that only a very small portion of the electrospray is deflected, leaving the majority of the electrospray in the normal emission direction, maintaining a continuous output of thrust.
Further, the external force is applied to the electrospray in the following implementation mode:
an electromagnetic coil is adopted, and Lorentz force is generated when the electromagnetic coil is electrified, so that part of the electric spray changes the flight direction under the action of the Lorentz force.
Further, the good conductor electrode is a faraday cage.
The invention has the further beneficial effects that: the integrated Faraday cage has simple structure, has strong practical prospect for space load such as a colloid propulsion system, and can be directly applied to the existing colloid electric propulsion system.
Further, when the faraday cage is a multi-layer grid structure and particle deceleration potentials exist among different levels of grids, the current signal generated by the impact is collected, specifically: detecting a current signal generated by the decelerated particles impacting the grid;
the processing of the current signal to obtain the physical characteristics of electrospray specifically comprises: and characterizing the kinetic energy distribution of the electrospray particles based on the current signal, and further analyzing the physical characteristics of the electrospray according to the kinetic energy distribution.
The invention also provides an electrospray on-track detection device of the colloid electric propulsion system, which comprises: the system comprises a colloid electric propulsion system to be tested, a deflection component, a good conductor electrode and a signal acquisition and processing component;
the colloid electric propulsion system to be tested emits electric spray in orbit; the deflection assembly is used for applying external force to the electrospray to deflect the flight direction of part of the electrospray; the good conductor electrode is arranged in the deflected flight direction and used for colliding with the partial electrospray to generate a current signal; and the signal acquisition and processing assembly is used for acquiring the current signal until the current signal disappears, and processing the current signal to obtain the physical characteristics of the electrospray so as to complete the on-track detection of the electrospray.
The invention has the beneficial effects that: the device realizes deflection sampling of flight electric spray based on the deflection component, realizes physical characteristic detection of electric spray based on the good conductor electrode and the signal acquisition processing component, is suitable for two colloid electric propulsion systems in an electric spray continuous jet working mode and an electric spray pulse jet working mode, can be matched with the existing performance detection technology for use, comprehensively analyzes the performance of the electric propulsion system, represents the thrust, specific impulse and emission efficiency of the in-orbit colloid electric propulsion system and the state information of whether the system is unstable or not, and has important significance for the efficient application of the colloid electric propulsion system. Particularly, the device of the invention provides a strategy idea of sampling the electrospray by adopting a deflection assembly, extracts only a very small part of the electrospray for inspection, does not influence the flight process of most of the electrospray in the normal emission direction, and can ensure the continuous thrust output capability of a propulsion system.
Further, the deflection component is a deflection electrode or an electromagnetic coil; wherein the content of the first and second substances,
the deflection electrode is used for applying a pulse electric field in the direction vertical to the emission direction so as to change the flight direction of part of the electrospray under the action of electrostatic force;
the electromagnetic coil is used for generating Lorentz force after the electromagnetic coil is electrified so that part of the electric spray changes the flight direction under the action of the Lorentz force.
Further, the good conductor electrode is a Faraday cage; wherein the content of the first and second substances,
when the Faraday cage is of a multi-layer grid mesh structure and particle deceleration potentials exist among grid meshes of different levels, the signal acquisition unit is specifically used for detecting current signals generated when decelerated particles impact the grid meshes; the signal processing unit is specifically configured to: and characterizing the kinetic energy distribution of the electrospray particles based on the current signal, and further analyzing the physical characteristics of the electrospray according to the kinetic energy distribution.
Furthermore, the deflection assembly, the good conductor electrode and the signal acquisition unit are all powered and controlled by the colloid electric propulsion system to be detected.
The invention has the further beneficial effects that: the system only needs to add a deflection component and a good conductor electrode in the original propeller system and is matched with a power supply of the propeller system for use, the volume, data and complexity of the system are not greatly increased, the system has a strong practical prospect for space loads such as a colloid propulsion system, can be directly applied to the existing colloid electric propulsion system, and can be applied to two working modes of an electric spray continuous jet colloid electric propulsion system and an electric spray pulse jet colloid electric propulsion system.
The invention also provides an on-orbit detection method for the performance of the colloid electric propulsion system, which is characterized in that the electric spray physical characteristics of the colloid electric propulsion system to be detected are obtained by adopting the electric spray on-orbit detection method for the colloid electric propulsion system, and the performance parameters and the state information of instability or not of the colloid electric propulsion system to be detected are obtained by analyzing based on the electric spray physical characteristics.
The invention has the beneficial effects that: the electric spray on-orbit detection method based on the colloid electric propulsion system can be matched with the existing performance detection technology for use, the system performance is comprehensively analyzed, the thrust, specific impulse and emission efficiency of the colloid electric propulsion system and the state information of whether the system is unstable or not are characterized in the in-orbit working environment of the colloid electric propulsion system, more detection information can be further provided for developing a more complex system automatic control strategy, and the efficient application of the colloid electric propulsion system is ensured.
Drawings
FIG. 1 is a block diagram of an electrospray on-track detection method for a colloidal electric propulsion system according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of an electrospray on-track detection device of a colloidal electric propulsion system according to an embodiment of the present invention;
fig. 3 is a diagram illustrating a result of numerical simulation calculation of a moving direction of charged particles in a zero potential/voltage applied state of a deflection electrode according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
Example one
An electrospray on-track detection method for a colloidal electric propulsion system, as shown in fig. 1, comprises:
when the electric spray emitted by the colloid electric propulsion system on the track flies according to the emission direction of the electric spray, external force is applied to the electric spray, so that the flying direction of part of the electric spray is deflected;
a good conductor electrode is arranged in the deflected flying direction, and when part of the electrospray flies to impact the good conductor electrode, a current signal generated by the impact is collected until the signal disappears;
and processing the current signal to obtain the physical characteristics of the electrospray, and completing the on-track detection of the electrospray.
The collected current signals can be analyzed and processed through a time-of-flight mass spectrometry method, and the physical characteristics of the electrospray are obtained. In addition, the magnitude of the external force applied to the electrospray can be set according to the actually required deflection angle.
The method samples the electric spray emitted by the colloid electric propulsion system by applying external force, the electric spray deflects in flight, the deflected electric spray is collected by the good conductor electrode after continuously flying for a fixed length in a free space, a time domain current signal generated when the electric spray impacts the good conductor electrode can be detected through an electrometer, accurate flight time mass spectrum information of the sampled electric spray can be obtained by carrying out signal processing on the current signal, and the method is suitable for two colloid electric propulsion system working modes of electric spray continuous jet and electric spray pulse jet. The mass spectrum information can be further analyzed to calculate the thrust, specific impulse, field emission divergence angle, emission flow, electrospray energy distribution, speed distribution information and the like of the colloid electric propulsion system at the moment, so that the real-time monitoring of the working performance of the electric propulsion system is realized, and the colloid electric propulsion system can be used for analyzing the working state of the colloid electric propulsion system.
In general, the method realizes deflection sampling of flight electrospray based on external force and realizes physical characteristic detection of electrospray based on flight time mass spectrometry. Therefore, the method can measure various electrospray physical characteristics which cannot be measured by the existing colloid propulsion system on-orbit performance characterization technology, such as: the system can be used in cooperation with the existing performance detection technology to comprehensively analyze the system performance, and can represent the thrust, specific impulse, emission efficiency and state information of whether the system is unstable or not in the in-orbit working environment of the colloidal electric propulsion system, further provide more detection information for developing a more complex system automatic control strategy, and has important significance for the efficient application of the colloidal electric propulsion system. Particularly, the method provides a strategy idea of sampling the electrospray, extracts only a very small part of the electrospray for inspection, does not influence the flight process of most of the electrospray in the normal emission direction, and ensures the continuous thrust output capability of a propulsion system.
Preferably, the external force is applied to the electrospray by the following implementation mode:
a pair of deflection electrodes is integrated on a colloid electric propulsion system and used for applying a high-voltage pulse electric field in the direction vertical to the emission direction of the electric spray so as to change the flight direction of charged ions and charged liquid drops in the electric spray under the action of electrostatic force.
By using the pulse voltage, the flight direction of part of the electric spray components flying through the deflection electrode during the period from the voltage starting to the voltage closing is deflected, so that the electric spray emitted by the colloid electric propulsion system is sampled, and the electric spray sampling device is simple in structure and high in operability. Wherein the magnitude of the applied pulse voltage amplitude can be set according to the actually required deflection angle.
Preferably, the duration of the applied pulsed electric field<10-6s。
Due to very short duration of use (<10-6s) deflecting and sampling the electrospray, so that only a few parts of the electrospray are deflected, and the vast majority of the electrospray is kept in the normal emission direction, and the continuous output of the thrust can be maintained.
The electrospray detection of the method provided by the embodiment can be realized by short pulse voltage sustainable time, so that the method can be combined with a colloid electric propulsion system in a continuous spraying working mode and can also be combined with a colloid propulsion system for realizing pulse field emission by using high-frequency alternating voltage, and deflection detection is carried out on partial pulse emission electrospray, so that other pulses can be kept emitting normally.
Preferably, the above-mentioned external force is applied to the electrospray, and another implementation manner is as follows:
and the electromagnetic coil is adopted to generate Lorentz force when the electromagnetic coil is electrified, so that the flight direction of the charged ions and charged liquid drops in the part of the electrospray is changed under the action of the Lorentz force, and the deflection sampling of the part of the electrospray is realized.
Preferably, the good conductor electrode is a faraday cage.
A group of metal electrodes are integrated in the flight direction of the electric spray after the electric spray deflects for a certain angle to form a Faraday cage structure, so that the electric spray impacts the Faraday cage after flying for a certain fixed length and is completely collected; the faraday cage may be connected to an electrometer so that a time domain current signal generated by sequential impact of ions and droplets in the electrospray may be measured by the electrometer.
It should be noted that when the method is used for detecting the electric spray of the in-orbit colloidal electric propulsion system, only two groups of metal electrode structures are needed to be added in the propeller system, the volume, the data and the complexity of the system are not greatly increased, and the method has a strong practical prospect for space loads such as the colloidal propulsion system and can be directly applied to the existing colloidal electric propulsion system. In addition, the deflection sampling time is extremely short and is in the millisecond order, so that the electrostatic deflection (or Lorentz force deflection) of the electrospray and the disturbance force generated when the electrospray static deflection (or Lorentz force deflection) and the Faraday cage are equal in size and opposite in direction, the electrostatic deflection (or Lorentz force deflection) and the impact force are not completely overlapped in the time domain, but disturbance signals (namely voltage signals applied to a deflection electrode or an electromagnetic coil, and the working time is extremely short) are in a higher frequency band (kHz-mHz), and the disturbance generated by low-frequency inertia measurement experiments taking space gravitational wave detection and satellite gravity measurement as examples is small.
Preferably, when the faraday cage is a multi-layer grid structure and particle deceleration potentials exist between different levels of grids, the collecting of the current signal generated by the impact includes: detecting a current signal generated by the decelerated particles impacting the grid; it should be noted that the multi-layer grid structure has a particle deceleration potential, and after the electrospray flies to the faraday cage and starts to impact, the speed of the electrospray particles is further reduced every time the electrospray particles pass through one layer of grid, and finally, a current signal generated after the electrospray particles impact the last layer of grid is collected. On this basis, the processing of the current signal to obtain the physical characteristics of electrospray specifically comprises: and characterizing the kinetic energy distribution of the electrospray particles based on the current signal, and further analyzing the physical characteristics of the electrospray according to the kinetic energy distribution. The Faraday cage adopting the multi-layer grid structure can generate one more kinetic energy distribution information compared with the Faraday cage adopting the single-layer grid structure so as to be used for the subsequent performance analysis of the electric propulsion system.
It should be noted that, in the following description,
to better illustrate the method, an example is now given, which is as follows:
(1) at the initial moment, the deflecting electrode and the Faraday cage are both zero potential and keep the same potential state with the shell of the propulsion system, and at the moment, the electrospray flies along the original direction;
(2) when the deflection component is an electromagnetic coil, the control power supply system energizes the electromagnetic coil to form a magnetic field. Finally deflecting the flying direction of part of the electrospray among the polar plates or in the coil to fly to a Faraday cage;
(3) at the falling edge of the pulse high voltage, the control system triggers the electrometer to start collecting deflected time domain current signals until the current signals completely disappear;
(4) the electrometer converts the current into a digital signal, transmits the digital signal to the satellite-borne computer to perform mass spectrometry on the signal, and transmits information to a ground user;
(5) and the deflecting electrode and the Faraday cage are both restored to a zero potential state to wait for the next detection.
Example two
An electrospray in-orbit detection device for a colloidal electric propulsion system, comprising: the device comprises a colloid electric propulsion system to be tested, a deflection assembly, a good conductor electrode, a signal acquisition unit and a signal processing unit. Wherein the content of the first and second substances,
the colloid electric propulsion system to be tested emits electric spray on the track; the deflection assembly is used for applying external force to the electrospray to deflect the flight direction of part of the electrospray; the good conductor electrode is arranged in the deflected flight direction and is used for colliding with part of the electrospray to generate a current signal; the signal acquisition unit is used for acquiring current signals until the current signals disappear, and the signal processing unit is used for processing the current signals to obtain the physical characteristics of the electrospray and complete the on-track detection of the electrospray.
The collected current signals can be analyzed and processed through a time-of-flight mass spectrometry method, and the physical characteristics of the electrospray are obtained. In addition, the magnitude of the external force applied to the electrospray can be set according to the actually required deflection angle.
Preferably, the deflection assembly is a deflection electrode or an electromagnetic coil.
Preferably, the good conductor electrode is a single-layer grid structure faraday cage or a multi-layer grid structure faraday cage.
Preferably, the deflection assembly, the good conductor assembly and the signal acquisition unit are all powered and controlled by the colloid electric propulsion system to be detected.
In the structure of the embodiment, only two groups of metal electrode structures, namely the deflection electrode (or the electromagnetic coil) and the good conductor electrode, need to be added in the original propeller system and are matched with the power supply of the propeller system for use, the volume, the data and the complexity of the system are not greatly increased, and the structure has a strong practical prospect for space loads such as a colloid propulsion system and can be directly applied to the existing colloid electric propulsion system.
The related technical solutions and the descriptions thereof are the same as those in the first embodiment, and are not described herein again.
The principles, structures and specific implementations related to the first embodiment and the second embodiment are further described below with reference to the accompanying drawings and embodiments:
as shown in fig. 2, in the colloid electric propulsion system, the working medium is transported to the front end of the emission structure, and under the combined action of the electric field force and the surface tension of the liquid, the front end of the liquid level forms a taylor cone under the negative high voltage applied by the electrode in the extraction acceleration region; the curvature radius of the cone tip is rapidly reduced, so that the number of charges accumulated in a unit area is increased, after the number density of the charges exceeds a certain threshold value, two physical processes of ion field emission and charged liquid droplet cone jet flow are simultaneously generated at the tip end of the Taylor cone, ions generated by emission and charged liquid jointly form electrospray, and the electrospray is accelerated and sprayed out by an electrostatic field passing between electrodes; then, the high-speed flying electrospray enters an ion beam focusing area, and the focusing and divergence angles of the electrospray are reduced by the electrostatic lens principle; next, the electrospray enters an ion beam deflection area, if the positive pulse high voltage is in a closed state, the electrospray keeps the original flight direction and leaves the propulsion system, if a positive pulse high voltage (or a negative pulse high voltage) is applied to a deflection electrode at the moment, ions and charged liquid drops in the electrospray are acted by electrostatic force, the flight direction is deflected, and then the electrospray continues to fly for a distance in the deflected direction and finally reaches a Faraday cage; after the deflected electrospray components strike the faraday cage in sequence, a time domain current signal can be measured on the faraday cage by an electrometer. Fig. 3 shows the results of numerical simulation calculation of particle trajectories of electrospray with different charge-to-mass ratio components through the "ion beam focusing region" and the "ion beam deflection region" before and after the deflection voltage is started. The result shows that after the positive pulse high voltage is started for 1 millisecond, the flight directions of the charged particles with different charge-mass ratios all generate obvious deflection, and the feasibility of the electrospray deflection-detection method provided by the invention is proved.
Example 1: and carrying out detection when the system is in the continuous injection working mode.
(1) At the initial moment, the deflecting electrode and the Faraday cage are both zero potential and keep the same potential state with the shell of the propulsion system, and at the moment, the electrospray flies along the original direction;
(2) the system control unit receives the detection instruction, and when the deflection assembly is a deflection electrode, the system control unit controls the power supply system to apply a pulse high voltage to the deflection electrode, and selects a proper pulse width according to the actual situation to form an electric field between the deflection electrode plates; or when the deflection assembly is an electromagnetic coil, the power supply system is controlled to supply power to the electromagnetic coil to form a magnetic field. Finally, deflecting the flight direction of the electrospray among the polar plates or in the coil, enabling the electrospray to fly to a Faraday cage, and detecting a time domain current signal by an electrometer;
(3) triggering an electrometer to start collecting deflected time domain current signals at a falling edge control system of the pulse high voltage until the current signals completely disappear;
(4) the electrometer converts the current into a digital signal, transmits the digital signal to the satellite-borne computer to perform mass spectrometry on the signal, and transmits information to a ground user;
(5) and the deflecting electrode and the Faraday cage are both restored to a zero potential state to wait for the next detection.
Example 2: and carrying out detection when the system is in a pulse jet working mode.
(1) At the initial moment, the deflecting electrode and the Faraday cage are both zero potential and keep the same potential state with the shell of the propulsion system, and at the moment, the electrospray flies along the original direction;
(2) the system control unit receives the detection instruction, controls the power supply system to apply a pulse high voltage to the deflection electrode or the electromagnetic coil at the next electrospray injection moment, selects a proper pulse width according to the actual condition, deflects the flight directions of all the electrospray injected by the current pulse, the electrospray flies to the Faraday cage, and the electrometer detects a time-domain current signal;
(3) triggering an electrometer to start collecting deflected time domain current signals at a falling edge control system of the pulse high voltage until the current signals completely disappear;
(4) the electrospray flies to a Faraday cage, and a time domain current signal is detected by an electrometer;
(5) the electrometer converts the current into a digital signal, transmits the digital signal to the satellite-borne computer to perform mass spectrometry on the signal, and transmits information to a ground user;
(6) and the deflecting electrode and the Faraday cage are both restored to a zero potential state to wait for the next detection.
EXAMPLE III
An on-orbit detection method for performance of a colloid electric propulsion system is adopted to obtain electric spray physical characteristics by adopting the electric spray on-orbit detection method for the colloid electric propulsion system in the embodiment I, and performance parameters and instability information of the colloid electric propulsion system are obtained through deduction based on the electric spray physical characteristics.
By analyzing the physical characteristics of the electrospray, the state of the electric propulsion system can be evaluated, for example: the thrust and the specific impulse of the electric propulsion system can be calculated by processing the electric spray current signal measured on the Faraday cage; the emission efficiency of the electric propulsion system can be analyzed by detecting the electric spray current measured on the Faraday cage and calculating the ratio of the electric spray current to the system emission current; the quality of sputtered electric spray on all electrode structures (including the deflection electrode provided by the method) in the colloid electric propulsion system can be analyzed by detecting the proportion of the mass flow of the spray to the consumption mass of the working medium, and the emission efficiency of the system can also be evaluated; the emission mode (such as a cone jet mode, a liquid drop mode and a multi-beam jet mode) of the electrospray emission can be analyzed by detecting the proportion of different components of the electrospray, and whether the system is unstable or not is judged; the fluctuation size of the physical characteristics of the electrospray is also an important reference factor for identifying whether the system is unstable or not.
The existing colloid electric propulsion system can only detect emission current as a unique performance characterization parameter when in on-orbit work, and the colloid electric propulsion system performance parameter has no unique corresponding relation with the emission current, so that the traditional method is difficult to comprehensively analyze the system working condition, and particularly cannot diagnose the system failure characteristics caused by the instability of electric spray emission. The method adopts the electric spray on-orbit detection method of the colloid electric propulsion system to obtain the physical characteristics of electric spray, and further can calculate the thrust, specific impulse, emission efficiency and the like of the propeller at the moment; finally, the system performance can be comprehensively analyzed, and whether the system is in a stable working state or not can be judged. Meanwhile, as mentioned above, the method provides a strategy idea of sampling the electrospray, so that the flight process of most electrospray in the normal emission direction is not influenced in the detection process, and the continuous thrust output capability of the propulsion system is ensured.
The related technical solution is the same as the first embodiment, and is not described herein again.
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (10)
1. An electrospray on-track detection method for a colloidal electric propulsion system, comprising:
when the electric spray emitted by the colloid electric propulsion system on the track flies according to the emission direction of the electric spray, applying external force to the electric spray, and deflecting the flying direction of part of the electric spray flying through an external force action area during the application of the external force;
a good conductor electrode is arranged in the deflected flight direction, and when the partial electrospray flies to impact the good conductor electrode, a current signal generated by the impact is collected until the signal disappears;
and processing the current signal to obtain the physical characteristics of the electrospray, and completing the on-track detection of the electrospray.
2. An electrospray on-track detection method for a colloidal electric propulsion system as claimed in claim 1, wherein said applying an external force to said electrospray is carried out by:
and applying a pulse electric field in a direction perpendicular to the emission direction by using a deflection electrode, so that part of the electrospray flying through the deflection polar plates during the period from the starting to the closing of the deflection voltage changes the flying direction under the action of electrostatic force.
3. An electrospray on-track detection method for a colloidal electric propulsion system as claimed in claim 2, wherein duration of application of said pulsed electric field is of duration<10-6s。
4. An electrospray on-track detection method for a colloidal electric propulsion system as claimed in claim 1, wherein said applying an external force to said electrospray is carried out by:
an electromagnetic coil is employed which generates a lorentz force when energized, such that a portion of the electrospray which flies past the electromagnetic coil during energization changes the direction of flight under the influence of the lorentz force.
5. An electrospray on-track detection method for a colloidal electric propulsion system as claimed in claim 1, wherein said good conductor electrode is a faraday cage;
when the faraday cage is of a multi-layer grid mesh structure and particle deceleration potentials exist among different levels of grid meshes, the current signal generated by the impact is collected, and the method specifically comprises the following steps: detecting a current signal generated by the decelerated particles impacting the grid;
the processing of the current signal to obtain the physical characteristics of electrospray specifically comprises: and characterizing the kinetic energy distribution of the electrospray particles based on the current signal, and further analyzing the physical characteristics of the electrospray according to the kinetic energy distribution.
6. An electrospray in-orbit detection device of a colloid electric propulsion system, comprising: the system comprises a colloid electric propulsion system to be tested, a deflection assembly, a good conductor electrode, a signal acquisition unit and a signal processing unit;
the colloid electric propulsion system to be tested emits electric spray in orbit; the deflection assembly is used for applying an external force to the electrospray so as to deflect the flying direction of part of the electrospray flying through the external force action area during the application of the external force; the good conductor electrode is arranged in the deflected flight direction and used for colliding with the partial electrospray to generate a current signal; the signal acquisition unit is used for acquiring the current signal until the current signal disappears; and the signal processing unit is used for processing the current signal to obtain the physical characteristics of the electrospray and complete the on-track detection of the electrospray.
7. An electrospray in-orbit detection device for a colloid electric propulsion system according to claim 6, wherein the deflection component is a deflection electrode or an electromagnetic coil; wherein the content of the first and second substances,
the deflection electrode is used for applying a pulse electric field in the direction vertical to the emission direction so that part of the electric spray flying through the deflection polar plates changes the flying direction under the action of electrostatic force during the period from the starting to the closing of the deflection voltage;
the electromagnetic coil is used for generating Lorentz force after the electromagnetic coil is electrified, so that part of the electric spray flying through the electromagnetic coil during the electrification changes the flying direction under the action of the Lorentz force.
8. An electrospray in-orbit detection device for a colloidal electric propulsion system as claimed in claim 6, wherein said good conductor electrode is a faraday cage; wherein the content of the first and second substances,
when the Faraday cage is of a multi-layer grid mesh structure and particle deceleration potentials exist among grid meshes of different levels, the signal acquisition unit is specifically used for detecting current signals generated when decelerated particles impact the grid meshes; the signal processing unit is specifically configured to: and characterizing the kinetic energy distribution of the electrospray particles based on the current signal, and further analyzing the physical characteristics of the electrospray according to the kinetic energy distribution.
9. An electrospray in-orbit detection device for a colloid electric propulsion system according to claim 6, wherein the deflection assembly, the good conductor electrode and the signal acquisition unit are all powered and controlled by the colloid electric propulsion system to be tested.
10. An on-orbit detection method for the performance of a colloid electric propulsion system, characterized in that the electric spraying physical characteristics of the colloid electric propulsion system to be tested are obtained by adopting the electric spraying on-orbit detection method for the colloid electric propulsion system according to any one of claims 1 to 5, and the performance parameters and the state information of instability or not of the colloid electric propulsion system to be tested are obtained through analysis based on the electric spraying physical characteristics.
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