A flow measurement device and control method for a solid iodine working fluid storage and supply system

Abstract

The present invention discloses a flow measurement device and control method for a solid iodine working medium storage and supply system, which belongs to the field of aerospace electric propulsion technology and is used to solve the problems of iodine working medium mass flow measurement and control difficulties in an electric propulsion system using solid iodine as a working medium. The flow measurement device includes an iodine vapor supply unit, an iodine vapor collection unit and a vacuum pump (7); one end of the iodine vapor collection unit is detachably connected to the iodine vapor supply unit, and the other end is detachably connected to the vacuum pump (7); the iodine vapor supply unit includes a steam generating tank (1) and a generating tank heater (3), and the generating tank heater (3) is used to heat the solid iodine working medium (2) in the steam generating tank (1); the iodine vapor collection unit includes a collecting chamber (8) and a refrigerator (9), and the refrigerator (9) is used to reduce the temperature in the collecting chamber (8). The invention is suitable for controlling the mass flow of iodine working medium in an electric propulsion system using solid iodine as a working medium.

Description

Technical Field

[0001] The present invention belongs to the field of aerospace electric propulsion technology, and in particular relates to a flow measurement device and a control method for a solid iodine working fluid storage and supply system. Background Art

[0002] With the continuous advancement of aerospace technology, the demands on spacecraft propulsion systems for various space missions, such as deep space exploration, orbit transfer, and station maintenance, are becoming increasingly diverse. Spacecraft propulsion systems are developing towards high specific impulse, long life, and high efficiency. Commercial spaceflight will further reduce flight costs, and space propulsion technology is constantly evolving.

[0003] Traditional chemical propulsion technology is bulky, expensive, and has low specific impulse when using xenon as a working fluid. Electric propulsion technology, on the other hand, has reached a relatively mature stage of research. It uses electricity to heat, dissociate, and accelerate the working fluid to form a high-speed jet, generating thrust. It offers advantages such as high specific impulse and lightweight design. Electric propulsion systems using solid iodine as a working fluid present significant challenges in flow measurement. Iodine vapor easily condenses, clogging pipelines, and is also material-selective. Conventional gas flow meters cannot be used. Mass flow must be calibrated for different solid iodine working fluid electric propulsion products to quickly and accurately provide stable and precise thrust to spacecraft, ensuring the smooth progress of space missions. Summary of the Invention

[0004] In view of the above analysis, the present invention aims to provide a flow measurement device and control method for a solid iodine working fluid storage and supply system, so as to solve the problems of difficulty in measuring and controlling the mass flow of iodine working fluid in an electric propulsion system using solid iodine as the working fluid.

[0005] The purpose of the present invention is mainly achieved through the following technical solutions:

[0006] A flow measurement device for a solid iodine working medium storage and supply system, comprising an iodine vapor supply unit, an iodine vapor collection unit, and a vacuum pump;

[0007] One end of the iodine vapor collecting portion is detachably connected to the iodine vapor supply portion, and the other end is detachably connected to the vacuum pump;

[0008] The iodine steam supply unit includes a steam generating tank and a generating tank heater, wherein the generating tank heater is used to heat the solid iodine working medium in the steam generating tank;

[0009] The iodine vapor collecting portion includes a collecting chamber and a refrigerator, and the refrigerator is used to reduce the temperature in the collecting chamber.

[0010] Furthermore, the iodine vapor collecting part further includes a three-way joint, a first connecting pipe, a second connecting pipe, a first isolation valve and a second isolation valve;

[0011] The three-way joint is arranged on the collecting chamber, the first end of the three-way joint is connected to the first connecting pipe, the second end of the three-way joint is connected to the second connecting pipe, and the third end of the three-way joint is connected to the collecting chamber; the first isolation valve is arranged at the end of the first connecting pipe, and the second isolation valve is arranged at the end of the second connecting pipe; the refrigerator is arranged outside the collecting chamber.

[0012] Furthermore, the first connecting pipe is connected to the vacuum pump via a fourth connecting pipe, and the second connecting pipe is connected to the steam generating tank via a third connecting pipe;

[0013] The first isolation valve at the end of the first connecting pipe is detachably connected to the fourth connecting pipe, and the second isolation valve at the end of the second connecting pipe is detachably connected to the third connecting pipe;

[0014] A third isolation valve is provided at one end of the third connecting pipe close to the steam generating tank.

[0015] Furthermore, a first heater is provided outside the first connecting pipe, the second connecting pipe and the three-way joint;

[0016] A second heater is provided outside the third connecting pipe;

[0017] A third heater is provided outside the fourth connecting pipe.

[0018] Furthermore, the device further comprises a timing device, which is used to accurately measure the iodine vapor supply time.

[0019] Furthermore, a weighing device is included, which is used to weigh the mass of the collection chamber before and after collecting iodine vapor.

[0020] A mass flow control method for a solid iodine working medium propulsion system, using a flow measurement device for a solid iodine working medium storage and supply system;

[0021] The following steps are involved:

[0022] S1 at a certain temperature, the iodine vapor collection before and after the iodine vapor collection portion was weighed, respectively, recorded as mass m0 and m1, and the iodine vapor supply time Δt is recorded;

[0023] S2. According to mass flow = (m1-m0) / Δt, the preliminary mass flow at this temperature is obtained;

[0024] S3. Correcting the preliminary mass flow to obtain a final mass flow;

[0025] S4. Repeat steps S1 to S3 at different temperatures to obtain the corresponding mass flow rate at different temperatures and make a calibration map;

[0026] S5. Adjusting the temperature of the solid-state iodine working fluid propulsion system according to the calibration map, thereby controlling the iodine vapor mass flow rate in the solid-state iodine working fluid propulsion system to a target value.

[0027] Furthermore, in said S1, the iodine vapor collecting unit collects the iodine vapor, comprising the following steps:

[0028] S11. The iodine vapor collecting portion is connected to the iodine vapor supply portion and a vacuum pump, and the first isolation valve, the second isolation valve and the third isolation valve are closed;

[0029] S12. Turn on the vacuum pump, turn on the first heater, the second heater and the third heater, and control the temperature at 85 to 100°C;

[0030] S13. When the vacuum level in the fourth connecting pipe reaches 1 Pa, the first, second, and third isolation valves are opened in sequence. After the first, second, third, and fourth connecting pipes and the steam generator are completely drained, the third, second, and first isolation valves are closed in sequence.

[0031] S14. The steam generator tank is heated, the temperature is controlled at a temperature within 50 to 110 ℃, and the timer is started; while the collection chamber is cooled, the temperature within the collection chamber is controlled within 10 to 20 ℃ by a refrigerator;

[0032] S15. After heating the steam generator tank for a period of time, the second isolation valve and the third isolation valve are opened sequentially to supply gas, and the iodine vapor flows into the collection chamber and is cooled and deposited in the collection chamber;

[0033] S16. After the second and third isolation valves are opened for a certain period of time, the third isolation valve is closed, the second isolation valve remains open, and the generator tank heater is turned off. After a period of time, the iodine vapor is collected.

[0034] Furthermore, in S4, before repeating S1 to S3, the iodine in the collection chamber is first removed.

[0035] Furthermore, in S1, when the iodine vapor collecting part collects iodine vapor, the flow device of the solid iodine working medium storage and supply system is placed as a whole in the vacuum chamber, and a solenoid valve is set between the third isolation valve and the second isolation valve as a switching valve for gas supply.

[0036] Furthermore, in said S3, the correction step is: first use a certain mass flow rate of Xe for ignition, record the RF power, screen grid voltage and beam parameters; control other test components unchanged, and change to iodine as the working fluid for ignition, use the mass flow rate of iodine that theoretically corresponds to the mass flow rate of Xe, and find the temperature XX°C corresponding to the mass flow rate of iodine from the temperature-mass flow rate relationship table of flow measurement. After obtaining the temperature, the steam generator tank 1 can be heated and temperature-controlled to XX°C, ignite stably, record the RF power, screen grid voltage and beam parameters, and compare them with the previous Xe test results. If the iodine test result is higher than that of Xe, it means that the flow rate corresponding to XX°C is too large, and the results are reasonably screened and the temperature below XX°C is re-selected for re-testing; vice versa.

[0037] Compared with the prior art, the present invention can achieve at least one of the following technical effects:

[0038] 1) The present invention is based on a mass flow calculation method that calculates the mass flow of iodine vapor according to the change in mass over a certain period of time. The present invention provides a precise measurement device for the iodine vapor flow rate of a solid iodine working fluid at different temperatures, which can achieve precise control of the thrust of the thrust system. The device has simple operation, safety and reliability, accurate calculation results, and wide applicability.

[0039] The accuracy of the mass flow rate of iodine vapor calculated by the measuring device of the present invention is better than 5 μg / s. The iodine working fluid temperature-flow calibration map obtained by the present invention can more accurately control the mass flow rate of iodine propulsion systems with different solid-state iodine working fluids, which is of great significance for accurately controlling thrust.

[0040] 2) Iodine vapor is highly corrosive, making mass flowmeters using Xe as the working fluid unusable. This invention can be applied to steam generators of varying thrust, while maintaining the same pipe dimensions. By using rectangular or cylindrical steam generators of varying specifications with similar temperature distributions, the heating profile of the "steam generator" can be replicated on a standard steam generator.

[0041] 3) Based on the mass flow calculation method, the present invention sublimes and condenses iodine to obtain a temperature-flow calibration map of the iodine working fluid, and uses a radio frequency ion thruster to ignite the beam to obtain the change in beam current. This is compared with the Xe beam current result to further accurately calibrate the temperature-flow of the iodine working fluid.

[0042] Other features and advantages of the present invention will be described in the following description, and in part they may become apparent from the description or may be understood through implementation of the present invention. The purposes and other advantages of the present invention may be realized and obtained through the structures particularly pointed out in the written description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The drawings are only for purposes of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference numerals designate like components throughout the drawings.

[0044] Figure 1 This is a structural diagram of a flow measurement device for a solid iodine working medium storage and supply system;

[0045] Figure 2 This is a schematic diagram of the flow measurement device of the solid iodine working fluid storage and supply system performing measurements in a vacuum chamber.

[0046] Reference numerals:

[0047] 1-steam generator tank; 2-iodine working medium; 3-generator tank heater; 4-first isolation valve; 5-second isolation valve; 6-third isolation valve; 7-vacuum pump; 8-collection chamber; 9-refrigerator; 10-three-way connector; 11-first connecting pipe; 12-second connecting pipe; 13-third connecting pipe; 14-fourth connecting pipe; 15-solenoid valve; 15-vacuum chamber; 16-circulating water cooling pump. DETAILED DESCRIPTION

[0048] The flow measurement device and control method for a solid iodine working medium storage and supply system are further described in detail below in conjunction with specific embodiments. These embodiments are only for comparison and explanation purposes, and the present invention is not limited to these embodiments.

[0049] A flow measurement device for a solid iodine working medium storage and supply system, such as Figure 1 As shown, the iodine vapor collection unit includes an iodine vapor supply unit, an iodine vapor collection unit, and a vacuum pump 7. One end of the iodine vapor collection unit is detachably connected to the iodine vapor supply unit, and the other end is detachably connected to the vacuum pump. The iodine vapor supply unit includes a steam generator tank and a generator tank heater, which is used to heat the solid iodine working medium in the steam generator tank. The iodine vapor collection unit includes a collection chamber and a refrigerator, which is used to reduce the temperature in the collection chamber.

[0050] The iodine vapor collection unit includes a collection chamber 8, a refrigerator 9, a three-way joint 10, a first connecting pipe 11, a second connecting pipe 12, a first isolation valve 4, and a second isolation valve 5; the three-way joint 10 is arranged on the collection chamber 8, the first end of the three-way joint 10 is connected to the first connecting pipe 11, the second end of the three-way joint 10 is connected to the second connecting pipe 12, and the third end of the three-way joint 10 is connected to the collection chamber 8; the first isolation valve 4 is arranged at the end of the first connecting pipe 11, and the second isolation valve 5 is arranged at the end of the second connecting pipe 12; the refrigerator 9 is arranged outside the collection chamber 8, illustratively, the refrigerator 9 is arranged at the bottom of the collection chamber 8, and preferably, the refrigerator 9 is evenly wrapped around the outer surface of the collection chamber 8; the iodine vapor supply unit includes a steam generator tank 1. Preferably, the first end and the second end of the three-way joint 10 are parallel.

[0051] The first connecting pipe 11 is connected to the vacuum pump 7 through the fourth connecting pipe 14, and the second connecting pipe 12 is connected to the steam generating tank 1 through the third connecting pipe 13; the first connecting pipe 11 and the fourth connecting pipe 14 are detachably connected, and the second connecting pipe 12 and the third connecting pipe 13 are detachably connected.

[0052] A third isolation valve 6 is installed at the end of the third connecting pipe 13 near the steam generator tank 1. To prevent iodine vapor from condensing in the connecting pipe before entering the collection chamber 8, which could clog the pipe and reduce measurement accuracy, a first heater is installed outside the first and second connecting pipes and the tee joint; a second heater is installed outside the third connecting pipe; and a third heater is installed outside the fourth connecting pipe.

[0053] Preferably, in order to prevent iodine vapor from condensing and depositing at the top of the collecting chamber 8, the pipeline is blocked and a heating plate is provided at the top of the collecting chamber and adhered to the top.

[0054] The flow measurement device for a solid-state iodine working fluid storage and supply system of the present invention is primarily used in solid-state iodine working fluid electric propulsion systems in the aerospace field. Based on a mass flow calculation method, the present invention calculates the mass flow rate of iodine vapor based on the change in mass over a certain period of time. The entire system is in a vacuum environment, where solid iodine sublimates upon heating and condenses and deposits in a collection chamber 8 through a piping system. The mass flow rate per unit time can be calculated. The present invention has a simple structure, reduces testing costs, is safe and reliable, is reusable, has high precision, and the working fluid is recyclable and pollution-free.

[0055] The accuracy of the mass flow rate of iodine vapor calculated by the measuring device of the present invention is better than 5 μg / s. The iodine working fluid temperature-flow calibration map obtained by the present invention can more accurately control the mass flow rate of iodine propulsion systems with different solid-state iodine working fluids, which is of great significance for accurately controlling thrust.

[0056] The steam generator tank 1 serves as a storage chamber for the solid iodine working medium 2. Its shape can be a rectangular, cylindrical or spherical storage structure. The material of the storage chamber is selected to be non-reactive with the solid iodine working medium 2. For example, the storage chamber is made of 316L stainless steel or other materials.

[0057] The first isolation valve 4, the second isolation valve 5 and the third isolation valve 6 are used as on / off gas circuit valves; the isolation valves are made of corrosion-resistant stainless steel, etc. For example, the isolation valves are made of 316L stainless steel.

[0058] The collection chamber 8 serves as a storage chamber for the iodine vapor condensation crystals. Its shape can be a rectangular parallelepiped, cylindrical, or spherical storage structure, but it must meet the characteristics of convenient measurement, easy removal of solid iodine crystals, and light dry weight. The material of the collection chamber 8 is selected to be corrosion-resistant, such as 316L stainless steel.

[0059] Exemplary, outside collecting chamber 8, a fourth heater is provided. After collecting chamber 8 completes the collection of iodine vapor and is weighed, collecting chamber 8 can be heated by the fourth heater to remove the iodine in collecting chamber 8. Exemplary, the removal of iodine in collecting chamber 8 can be directly heated after the iodine vapor collecting portion is weighed, to remove the iodine in collecting chamber 8; Alternatively, the iodine vapor collecting portion can be connected to the iodine vapor supply portion and vacuum pump 7 again after weighing, then the collecting chamber 8 is heated, and the iodine in collecting chamber 8 is flowed back into the steam generating tank 1. In one embodiment, when measuring, a refrigerator outside the collecting chamber is started, and the iodine in the pipeline can be all collected in the collecting chamber; When the iodine collection inside the collecting chamber reaches a certain amount, the refrigerator is turned off, and the fourth heater on the collecting chamber surface is started, which can be used as a generator of iodine vapor to discharge the iodine inside the collecting chamber.

[0060] The shape of the heater can be designed according to the steam generating tank 1 and the pipeline through which the iodine steam flows. The heater can be in the form of a heating plate, a heating wire, or a heating device with other functions. The material is selected to be corrosion-resistant and temperature-resistant, such as a polyimide heating plate, a ceramic heating plate, etc.

[0061] The shape of the refrigerator 9 is designed according to the collection chamber 8, and can be liquid nitrogen cooling, ceramic cooling plate and cold water. For example, Figure 2 As shown, the refrigerator includes a water-cooled plate and a circulating water-cooling pump 16. The water-cooled plate is disposed at the bottom of the collection chamber. The circulating water-cooling pump 16 is connected to the water-cooled plate to circulate cooling water within the water-cooled plate. However, it is important to prevent refrigerant gas from entering the connecting pipe, steam generator tank 1, or collection chamber 8, where it could chemically react with iodine. Furthermore, it is also important to prevent factors such as water vapor from affecting the weighing process.

[0062] In order to improve the sealing performance between the first, second and third isolation valves and the connected pipelines, it is preferred that a ferrule is provided at the inlet and outlet of each isolation valve. This ensures that the sealing performance of the pipeline as a whole can be guaranteed even after multiple disassembly and installation of the isolation valve. The connection is connected by a ferrule, and the single point leakage rate can reach 1.0E-7Pa.m 3 / s, when the collection chamber is cooled and weighed in the atmospheric environment (vacuum inside), water vapor can be prevented from entering the collection chamber.

[0063] The solid-state iodine working medium storage and supply system flow measurement device of the present invention also includes a weighing device, which is used to weigh the mass before and after the collection chamber 8 collects the iodine vapor. Exemplary, the weighing device is a balance, and the resolution of the balance needs to be better than 0.001g, and the maximum weighing range is 1kg. Since the flow corresponding to the thrust of the current supporting thruster is micrograms / second, the change of mass flow is more accurate. The precision of the balance and the selection of the maximum weighing range are accurately calculated according to the mass of the collection chamber 8. The iodine vapor collecting part includes the total mass of the cable and the multilayer and needs to be guaranteed to be half of the maximum weighing of the balance, so that the balance weighing is more accurate; for precision, the precision of the 0.001g level is more suitable for microgram flow.

[0064] The third connecting pipe 13 is the sole channel connecting the steam generator tank 1 and the collection chamber 8. Its shape can be designed based on actual requirements. The first, second, third, and fourth connecting pipes 11, 12, 13, and 14 are all made of corrosion-resistant and high-temperature-resistant materials, such as 316L stainless steel. The pipe shapes are tailored to the requirements, exemplified by 1 / 8, 1 / 4 stainless steel pipes, or polytetrafluoroethylene tubes. The first, second, and third heaters heat the pipes to prevent iodine vapor from accumulating therein.

[0065] The flow measurement device for the solid-state iodine working medium storage and supply system of the present invention further includes a timing device for accurately recording the iodine vapor supply time. Exemplarily, the timing device can be a stopwatch, which records the time it takes for the solid iodine working medium 2 to convert into iodine vapor and flow into the collection chamber 8 within a specified time period, thereby obtaining a mass flow rate with an accuracy better than 5 μg / s.

[0066] The flow measurement device of the solid-state iodine working medium storage and supply system of the present invention further comprises a plurality of temperature sensors for monitoring the temperatures at different temperature points.

[0067] The test range of the device of the present invention for the mass flow rate of the iodine working medium 2 can reach 39 μg / s to 8 mg / s.

[0068] Since iodine vapor is toxic, a good sealing system is required and the system leakage rate is guaranteed to be 1.0E-8Pa.m 3 / s; To ensure safety, in one embodiment, the entire device can be placed in a vacuum chamber 15, such as Figure 2 As shown, corrosion-resistant, electrically controllable valves, such as solenoid valves 14, are installed between the second isolation valve 5 and the third isolation valve 6, or both the second isolation valve 5 and the third isolation valve 6 are replaced with electrically controllable solenoid valves. If the entire device is placed in a vacuum, the solenoid valves are controlled to open by the peripheral circuit during gas supply and weighing, and the gas is condensed in the vacuum before weighing.

[0069] The present invention also provides a mass flow control method for a solid iodine working medium propulsion system, which uses the above-mentioned solid iodine working medium storage and supply system flow measurement device;

[0070] The following steps are involved:

[0071] S1 at a certain temperature, the iodine vapor collection before and after the iodine vapor collection portion was weighed, respectively, recorded as mass m0 and m1, and the iodine vapor supply time Δt is recorded;

[0072] S2. According to mass flow = (m1-m0) / Δt, the preliminary mass flow at this temperature is obtained;

[0073] S3. Correcting the preliminary mass flow to obtain a final mass flow;

[0074] Specifically, after calibrating the relationship between the temperature and mass flow rate of the iodine working fluid, the experimental results of ignition to generate a beam at a series of Xe flow rates were used. The same thruster was used and the temperature at a flow rate corresponding to Xe (such as a Xe flow rate of 1sccm, compared to an iodine mass flow rate of the order of 100ug / s) was used to perform ignition, compare the beam size, and correct the temperature-mass flow rate.

[0075] Specifically, when using beam current to calibrate the relationship between the temperature and mass flow rate of the iodine working fluid, first use a certain mass flow rate of Xe for ignition, and record parameters such as RF power, screen grid voltage, and beam current; control other test components unchanged, and when changing to iodine as the working fluid for ignition, use the mass flow rate of iodine that theoretically corresponds to the mass flow rate of Xe, and find the temperature XX°C corresponding to this iodine mass flow rate from the temperature-mass flow rate relationship table of flow measurement. After obtaining the temperature, the steam generator tank 1 can be heated and temperature-controlled to XX°C, ignited stably, and parameters such as RF power, screen grid voltage, and beam current are recorded and compared with the previous Xe test results. If the iodine test result is higher than that of Xe, it means that the flow rate corresponding to XX°C is too large, and the results are reasonably screened and a temperature below XX°C is re-selected for re-testing; vice versa.

[0076] For example: first use a Xe mass flow rate of 1 sccm for ignition, and record parameters such as RF power, screen grid voltage, and beam current; control other test components unchanged, and change to iodine as the working fluid for ignition. Theoretically, when the Xe mass flow rate is 1 sccm, the corresponding iodine mass flow rate is 100ug / s. From the temperature-mass flow relationship table of flow measurement, find out that the temperature corresponding to the mass flow rate of 100ug / s is XX℃. After obtaining the temperature, the steam generator tank 1 can be heated and temperature-controlled to XX℃, ignite stably, record RF power, screen grid voltage, and beam current and other parameters, and compare with the previous Xe test results. If the iodine test result is higher than that of Xe, it means that the flow rate corresponding to XX℃ is too large. The results should be reasonably screened and the temperature below XX℃ should be re-selected for re-testing; vice versa. S4. Repeat steps S1 to S3 at different temperatures to obtain the corresponding mass flow rates at different temperatures and make a calibration map;

[0077] S5. Adjust the temperature of the solid-state iodine working fluid propulsion system according to the calibration map, thereby controlling the iodine vapor mass flow rate in the solid-state iodine working fluid propulsion system to a target value.

[0078] The present invention provides a mass flow control method for a solid iodine working medium propulsion system, which can achieve precise control of the thrust of the thrust system, has simple operation, is safe and reliable, has accurate calculation results, and has wide applicability.

[0079] Specifically, in S1, the iodine vapor collecting unit collects iodine vapor, including the following steps:

[0080] S11. Connect the iodine vapor collecting part to the iodine vapor supply part and the vacuum pump 7. At this time, the first isolation valve 4, the second isolation valve 5 and the third isolation valve 6 are all closed.

[0081] S12. Start the vacuum pump 7 and the first, second, and third heaters, controlling the temperature between 85°C and 100°C. The temperature of the pipeline is set within the temperature range determined by the isolation valve's heat resistance to prevent excessive temperatures from aging or causing failure of components such as gaskets within the isolation valve. Preferably, the pipeline temperature is 10°C to 20°C higher than the temperature of the steam generator tank.

[0082] S13. When the vacuum degree in the fourth connecting pipe 14 reaches the level of 1 Pa, open the first isolation valve 4, the second isolation valve 5 and the third isolation valve 6 in sequence; after the air in the first connecting pipe 11, the second connecting pipe 12, the third connecting pipe 13, the fourth connecting pipe 14 and the steam generator is completely discharged, close the third isolation valve 6, the second isolation valve 5 and the first isolation valve 4 in sequence.

[0083] S14. Heat the steam generating tank 1 and start timing, controlling the temperature to a certain temperature within the range of 50-110°C. If the temperature of the steam generating tank 1 is too high, the solid iodine working medium 2 inside will melt into liquid, which is more dangerous. At the same time, cool the collecting chamber 8 and use the refrigerator 9 to control the temperature inside the collecting chamber 8 within the range of 10-20°C. When the temperature of the collecting chamber 8 is higher than 30°C, the iodine vapor deposition and condensation are less, and the iodine vapor cannot enter the collecting chamber 8 completely. The temperature of the collecting chamber 8 is maintained within the range of 10-20°C, which can basically ensure that all iodine vapor enters the collecting chamber 8. If the temperature of the collecting chamber 8 is too high and the pressure is too high, the iodine vapor cannot flow in normally, resulting in a large measurement error. When the temperature of the collecting chamber 8 is too low, the pressure is low. The temperature of the collecting chamber will have a great impact on the flow rate. This application controls the temperature of the collecting chamber at 10-20°C. When the temperature of the collecting chamber 8 is higher than 30°C and the temperature of the collecting chamber is controlled at 10-20°C, the mass flow rates measured at a large flow rate (exemplarily, 300ug / s) differ by approximately 8-10 times. S15. After heating the steam generator tank 1 for a period of time (the heating time refers to heating from room temperature to the target temperature, and the target temperature is stable, which takes about 1 to 2 hours. The valve will not open during the heating time, and no iodine vapor will enter the collecting chamber. Exemplarily, the heating time can be 2 hours), open the second isolation valve 5 and the third isolation valve 6 in turn, and the iodine vapor flows into the collecting chamber 8, and is deposited in the collecting chamber 8 when it is cooled;

[0084] S16. After the second and third isolation valves 5 and 6 are opened (supplying gas) for a certain period of time (illustratively, the supply time is 2 hours), the third isolation valve 6 is closed, the second isolation valve 5 remains open, the generator tank heater 3 is turned off, and the iodine vapor collection is completed after a period of time (illustratively, the collection is considered complete after the third isolation valve is closed for 15-20 minutes). The opening time of the second and third isolation valves 5 and 6 is the supply time Δt.

[0085] Preferably, 1 hour before gas supply, the heating plate on the top of the collecting chamber 8 is turned on to increase the temperature of the top of the collecting chamber 8 to prevent premature heating from raising the temperature of the bottom of the collecting chamber 8.

[0086] Furthermore, in S4, before repeating S1 to S3, the iodine in the collection chamber 8 is removed.

[0087] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A flow measurement device for a solid iodine working medium storage and supply system, characterized in that: It comprises an iodine vapor supply part, an iodine vapor collection part and a vacuum pump (7); one end of the iodine vapor collection part is detachably connected to the iodine vapor supply part, and the other end is detachably connected to the vacuum pump (7); The iodine vapor supply unit comprises a steam generating tank (1) and a generating tank heater (3), wherein the generating tank heater (3) is used to heat the solid iodine working medium (2) in the steam generating tank (1) to a target temperature of 50-110° C.; the iodine vapor collecting unit comprises a collecting chamber (8) and a refrigerator (9), wherein the refrigerator (9) is used to reduce the temperature in the collecting chamber (8) to 10-20° C.; the refrigerator is arranged at the bottom of the collecting chamber, and a heating plate is arranged at the top of the collecting chamber to prevent the iodine vapor from condensing and depositing at the top of the collecting chamber and blocking the pipeline; The iodine vapor collecting portion further comprises a three-way connector (10), a first connecting pipe (11), a second connecting pipe (12), a first isolation valve (4) and a second isolation valve (5); The three-way joint (10) is arranged on the collecting chamber (8), the first end of the three-way joint (10) is connected to the first connecting pipe (11), the second end of the three-way joint (10) is connected to the second connecting pipe (12), and the third end of the three-way joint (10) is connected to the collecting chamber (8); the first isolation valve (4) is arranged at the end of the first connecting pipe (11), and the second isolation valve (5) is arranged at the end of the second connecting pipe (12); the refrigerator (9) is arranged outside the collecting chamber (8); The first connecting pipe (11) is connected to the vacuum pump (7) via a fourth connecting pipe (14), and the second connecting pipe (12) is connected to the steam generating tank (1) via a third connecting pipe (13); The first isolation valve (4) at the end of the first connecting pipe (11) is detachably connected to the fourth connecting pipe (14), and the second isolation valve (5) at the end of the second connecting pipe (12) is detachably connected to the third connecting pipe (13); and a third isolation valve (6) is provided at one end of the third connecting pipe (13) close to the steam generating tank (1).

2. The flow measurement device for the solid iodine working medium storage and supply system according to claim 1, characterized in that: A first heater is provided outside the first connecting pipe (11), the second connecting pipe (12) and the three-way joint (10); A second heater is provided outside the third connecting pipe (13); A third heater is provided outside the fourth connecting pipe (14).

3. The flow measurement device for the solid iodine working medium storage and supply system according to claim 1, characterized in that: The device also comprises a timing device, which is used for accurately measuring the supply time of iodine vapor.

4. The flow measurement device for a solid iodine working medium storage and supply system according to any one of claims 1 to 3, characterized in that: It also includes a weighing device, which is used to weigh the mass of the collection chamber (8) before and after collecting iodine vapor.

5. A mass flow control method for a solid iodine working medium propulsion system, characterized in that: A flow measurement device for a solid iodine working medium storage and supply system according to any one of claims 2 to 4; The following steps are involved: S1. At a certain temperature, the iodine vapor is collected before and after the iodine vapor collection chamber is weighed, respectively, recorded as mass m0 and m1, and the iodine vapor supply time Δt is recorded; S2. According to mass flow = (m1-m0) / Δt, the preliminary mass flow at this temperature is obtained; S3. Correcting the preliminary mass flow to obtain a final mass flow; S4. Repeat steps S1 to S3 at different temperatures to obtain the corresponding mass flow rate at different temperatures and make a calibration map; S5. Adjusting the temperature of the solid-state iodine working fluid propulsion system according to the calibration map, thereby controlling the iodine vapor mass flow rate in the solid-state iodine working fluid propulsion system to a target value.

6. The mass flow control method for a solid iodine working medium propulsion system according to claim 5, characterized in that: In S1, the iodine vapor collecting unit collects iodine vapor, including the following steps: S11. The iodine vapor collecting portion is connected to the iodine vapor supply portion and the vacuum pump (7), and the first isolation valve (4), the second isolation valve (5) and the third isolation valve (6) are all closed; S12. Turn on the vacuum pump (7), turn on the first heater, the second heater and the third heater, and control the temperature at 85 to 100 ° C; S13. When the vacuum degree in the fourth connecting pipe (14) reaches the level of 1 Pa, the first isolation valve (4), the second isolation valve (5) and the third isolation valve (6) are opened in sequence; after the first connecting pipe (11), the second connecting pipe (12), the third connecting pipe (13), the fourth connecting pipe (14) and the steam generator are completely discharged, the third isolation valve (6), the second isolation valve (5) and the first isolation valve (4) are closed in sequence; S14. The steam generating tank (1) is heated and the temperature is controlled at a temperature within the range of 50 to 110°C, and the timing is started; while the collecting chamber (8) is cooled, and the temperature within the collecting chamber (8) is controlled within 10 to 20°C by a refrigerator (9); S15. After the steam generating tank (1) is heated for a period of time, the second isolation valve (5) and the third isolation valve (6) are opened in sequence to supply gas, and the iodine vapor flows into the collecting chamber (8) and is deposited in the collecting chamber (8) when cooled; S16. After the second isolation valve (5) and the third isolation valve (6) are opened for a certain period of time, the third isolation valve (6) is closed, the second isolation valve (5) continues to be opened, and the generator tank heater (3) is closed. After a period of time, the iodine vapor is collected.

7. The mass flow control method of the solid iodine working medium propulsion system according to claim 6, characterized in that: In S4, before repeating S1 to S3, the iodine in the collection chamber (8) is first removed.

8. The mass flow control method of the solid iodine working medium propulsion system according to claim 6, wherein in S1, when the iodine vapor collecting part collects iodine vapor, the solid iodine working medium storage and supply system flow device is placed as a whole in the vacuum chamber (15), and an electromagnetic valve is provided between the third isolation valve (6) and the second isolation valve (5) as a switch valve for gas supply.

Images