Aerosol sampling measurement system for use in a steam flow system and method of controlling the same

Abstract

The present application relates to aerosol measurement technical field, specifically to a kind of aerosol sampling measurement system and control method suitable for steam flow system, including primary and secondary sampling structure, gas filling structure, fully developed structure, discharge structure, control host computer and aerosol measurement host computer;Sampling end of primary sampling structure is arranged in target measurement environment, gas filling structure is arranged downstream of primary sampling structure, its outer side is provided with heating jacket and its outer wall is communicated with exhaust pipe and gas injection pipe, gas filling structure is communicated to the gas inlet of primary sampling structure and the gas outlet between gas injection pipe, and convection is formed;Fully developed structure is arranged downstream of gas filling structure, and sampling end of secondary sampling structure is arranged in fully developed structure;Discharge structure is arranged downstream of fully developed structure.The present application can effectively avoid steam condensation phenomenon in gas mixing process, and realize aerosol equal-speed sampling under high gas flow rate change range.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aerosol measurement, in particular to an aerosol sampling and measuring system suitable for a steam flow system and a control method thereof. BACKGROUND

[0002] The occurrence of a severe reactor accident is accompanied by core melt-down, which in turn releases a large amount of radioactive substances and water vapor, and part of the radioactive substances will appear in the form of aerosols, which further leads to the formation of a high-temperature and high-pressure steam flow environment containing radioactive aerosols in the primary or secondary circuit pipeline under different accident processes. Considering the strong diffusion and adsorption of aerosols, in order to reasonably evaluate the migration and release of radioactive substances, experiments need to be carried out to accurately predict the aerosol settling behavior under this environment, which involves the corresponding aerosol concentration measurement requirements.

[0003] The commonly used measuring devices are online measuring equipment such as optical particle size spectrometer and multi-stage impactor, and offline measuring methods such as filter membrane filtration weighing, solution washing absorption and chemical detection. However, the existing offline measurement methods cannot obtain aerosol particle size distribution data. Because of the lack of accurate control of flow rate, all measurement methods are not suitable for pure steam environment. The condensation of steam during the sampling process makes it difficult to accurately control the steam flow rate for offline measurement methods, and most online measurement equipment is not suitable for pure steam environment. In addition, the fixed sampling flow rate requirements of various equipment are often not suitable for the equal-speed sampling principle of aerosols in a flow environment, especially in a high flow rate environment. The sampling flow rate that meets the equal-speed sampling principle is often much larger than the rated flow rate of the measuring equipment. SUMMARY

[0004] The purpose of the present application is to provide an aerosol sampling and measuring system suitable for a steam flow system and a control method thereof. Through the air charging structure, the steam partial pressure and temperature in the gas space can be reduced in stages, while avoiding the condensation of steam and reducing the diffusion phoretic loss of aerosols. The control logic based on multiple physical parameters such as pressure, temperature and flow rate can ensure the automatic operation of the system under the target working condition, realize the equal-speed sampling function of aerosols in a high gas flow rate change range, and solve the technical problems pointed out in the background art.

[0005] The present application is achieved by the following technical solution: an aerosol sampling and measuring system suitable for a steam flow system, comprising a primary sampling structure, a gas charging structure, a fully developed structure, a discharge structure, a secondary sampling structure, a measurement and control host and an aerosol measuring host.

[0006] The sampling end of the first sampling structure is arranged in a target measurement environment, and the gas filling structure is arranged downstream of the first sampling structure, and the gas filling structure is provided with a heating jacket on the outer side and is communicated with the exhaust pipe and the gas injection pipe, the gas filling structure is communicated between the gas inlet of the first sampling structure and the gas outlet of the gas injection pipe to form a convection, and the heating jacket is electrically connected with the direct current power supply.

[0007] The fully developed structure is arranged downstream of the gas filling structure, the sampling end of the second sampling structure is arranged in the fully developed structure, and the measurement probe is arranged downstream of the second sampling structure and is connected in communication with the aerosol measurement host.

[0008] The exhaust structure is arranged downstream of the fully developed structure, and the exhaust pipe, the gas injection pipe and the exhaust structure are all provided with a flow meter, a pressure sensing device, a temperature sensing device and a flow regulating valve, the flow meter, the pressure sensing device and the temperature sensing device are all connected in communication with the signal input end of the measurement and control host, and the signal output end of the measurement and control host is connected in communication with the flow regulating valve.

[0009] According to a preferred embodiment, the sampling end of the first sampling structure and the sampling end of the second sampling structure are both L-shaped.

[0010] According to a preferred embodiment, the downstream of the second sampling structure is further provided with a condensate tank and a steam-water separation filter in sequence.

[0011] According to a preferred embodiment, the gas filling structure comprises an outer cylinder, the outer cylinder is provided with a central flow channel and a plurality of stepped flow channels distributed in annular form outside the central flow channel, the exhaust pipe and the gas injection pipe are both communicated with the plurality of stepped flow channels, the plurality of stepped flow channels are communicated with the central flow channel, the first end of the central flow channel is communicated with the first sampling structure, and the second end of the central flow channel is communicated with the fully developed structure.

[0012] According to a preferred embodiment, the first end of the central flow channel has a smaller inner diameter than the second end of the central flow channel, the outlet of the first sampling structure has a smaller inner diameter than the first end of the central flow channel, and the inlet of the fully developed structure has an inner diameter equal to the second end of the central flow channel.

[0013] According to a preferred embodiment, the outer cylinder is provided with a plurality of inner cylinders with different outer diameters, the plurality of inner cylinders are distributed in a stepped form and jointly form the plurality of stepped flow channels with the inner wall of the outer cylinder, wherein the inner cylinder with a larger outer diameter is arranged adjacent to the second end of the central flow channel, the inner cylinder with a smaller outer diameter is arranged adjacent to the first end of the central flow channel, the gas injection pipe is arranged outside the inner cylinder with a larger outer diameter, and the exhaust pipe is arranged outside the inner cylinder with a smaller outer diameter.

[0014] According to a preferred embodiment, the first end of the inner cylinder is sleeved with a gas guide ring rib, and a plurality of flow guide holes are formed on the second end of the inner cylinder and the gas guide ring rib, the flow guide holes have inclined openings to form inclined flow channels intersecting with the multi-stage stepped flow channels and communicating with the central flow channel, and the inclined flow channels are located between adjacent inner cylinders.

[0015] According to a preferred embodiment, the outer side of the inner cylinder is sleeved with a flow distribution ring rib, and a plurality of uniformly distributed flow distribution holes are formed on the flow distribution ring rib.

[0016] The application also provides a control method for an aerosol sampling and measuring system suitable for a steam flow system, comprising the following steps:

[0017] Under the premise that the pressure, flow rate and temperature of the gas in the gas filling structure and the fully developed structure meet the experimental requirements, open the ball valve on the secondary sampling structure;

[0018] Obtain the filling gas flow rate Q1 of the gas injection pipe, the exhaust gas flow rate Q2 of the exhaust pipe and the gas flow rate Q4 of the primary sampling structure, and calculate the mixed gas ratio of the fully developed structure;

[0019] Based on the mixed gas ratio and the mixed gas temperature of the fully developed structure, calculate the mixed gas density;

[0020] Based on the mixed gas density, adjust the flow rate of the gas downstream of the secondary sampling structure to meet the density requirements of the particle size spectrometer;

[0021] According to the dilution ratio and the original aerosol particle size distribution, calculate the actual aerosol particle size distribution, and the dilution ratio is determined according to the flow rate adjustment amount of the gas downstream of the secondary sampling structure.

[0022] According to a preferred embodiment, the steps of building a scene meeting the experimental requirements are as follows:

[0023] Step 1, obtain the pressure data P0 inside the target measurement environment, the pressure data P1 inside the gas injection pipe, the pressure data P2 inside the exhaust pipe and the pressure data P3 inside the fully developed structure, determine whether the pressure data meets the first preset condition, if yes, go to step 2, the first preset condition is P1>P1>P0>P3>10kPa;

[0024] If not, generate a first control instruction, the first control instruction is used to instruct to adjust the opening degree of the flow rate adjustment valve on the gas injection pipe, the exhaust pipe and the exhaust structure in sequence;

[0025] Step 2, obtaining the filling gas flow rate Q1 of the gas injection pipe, the exhaust gas flow rate Q2 of the exhaust pipe and the mixed gas flow rate Q3 of the fully developed structure, calculating the gas flow rate Q4 of the primary sampling structure based on Q1, Q2, Q3, P0 and the gas temperature T0 in the target measurement environment, converting the gas flow rate V2 of the primary sampling structure according to Q4, determining whether V2 meets the second preset condition, if yes, going to step 3, the second preset condition is that the difference between V2 and the gas flow rate V1 in the target measurement environment is less than a preset threshold value;

[0026] Otherwise, a second control instruction is generated, which is used to instruct to adjust the opening degree of the flow regulating valve on the exhaust structure;

[0027] Step 3, obtaining the filling gas temperature T1 of the gas injection pipe, the exhaust gas temperature T2 of the exhaust pipe and the mixed gas temperature T3 of the fully developed structure, determining whether the temperature data meets the third preset condition, if yes, going to step 4, the third preset condition is that T1 and T2 both meet the system operation requirement and T3 is in a preset temperature range;

[0028] If not, a third control instruction is generated, which is used to instruct to adjust the heating power of the heating jacket, and the opening degrees of the flow regulating valves on the gas injection pipe and the exhaust pipe are adjusted in sequence when the heating power is out of limit.

[0029] The technical scheme of the aerosol sampling and measuring system suitable for a steam flow system and the control method thereof provided by the present application has at least the following advantages and beneficial effects:

[0030] (1) The stage heating mode of air can effectively avoid the steam condensation phenomenon in the gas mixing process through the convection type air filling structure, and the radial gas filling structure design can apply a force away from the wall surface to the aerosol, thereby solving the problem of aerosol concentration measurement in a pure steam environment, reducing the wall surface loss of the aerosol in the sampling process and improving the accuracy of the measurement results;

[0031] (2) The measurement of the aerosol concentration in a steam environment can be realized by increasing the air filling process and performing real-time gas flow control;

[0032] (3) The control logic based on multiple physical parameters such as pressure, temperature and flow rate can ensure the automatic operation of the system under the target working condition, and realize the isokinetic sampling function of the aerosol in a high gas flow rate change range. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 The structure schematic diagram of the aerosol sampling and measuring system suitable for a steam flow system provided for the embodiment 1 of the present application;

[0034] Figure 2A structural schematic diagram of the gas filling structure provided for the embodiment 2 of the present application;

[0035] Figure 3 A structural schematic diagram of the multi-stage inner cylinder provided for the embodiment 2 of the present application;

[0036] Figure 4 A structural schematic diagram of the flow distribution ring rib provided for the embodiment 2 of the present application;

[0037] Figure 5 A flowchart of the control method provided for the embodiment 3 of the present application;

[0038] The reference signs: 1-temperature sensing device, 2-pressure sensing device, 3-vortex flowmeter, 4-flow regulating valve, 5-ball valve, 6-primary sampling structure, 7-gas filling structure, 8-direct current power supply, 9-gas injection pipe, 10-gas discharge pipe, 11-full development structure, 12-discharge structure, 13-secondary sampling mechanism, 14-measuring probe, 15-condensate tank, 16-steam-water separation filter, 17-drain valve, 18-flow controller, 19-aerosol measurement host, 20-measuring and control host, 21-connection flange, 22-sealing structure, 23-ring rib support structure, 24-flow distribution ring rib, 25-gas flow guide ring rib, 26-flow guide hole, 27-flow distribution hole, 28-inner cylinder. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0040] Embodiment 1

[0041] The present embodiment provides an aerosol sampling and measuring system suitable for a steam flow system, Figure 1 A structural schematic diagram of the aerosol sampling and measuring system suitable for the steam flow system, as shown in Figure 1 The aerosol sampling and measuring system suitable for the steam flow system includes a primary sampling structure 6, a gas filling structure 7, a full development structure 11, a discharge structure 12, a secondary sampling structure, a measuring and control host 20 and an aerosol measurement host 19.

[0042] The sampling end of the primary sampling structure 6 is arranged in a target measuring environment; the sampling end of the primary sampling structure 6 in the present embodiment adopts an L-shaped design to ensure that the incoming flow aerosol can flow through the L-shaped sampling end uniformly and enter the gas filling structure 7.

[0043] The gas filling structure 7 is arranged downstream of the primary sampling structure 6 to reduce the temperature, speed and air pressure of the sampling gas, thereby providing stable mixed gas proportions for the secondary sampling structure; further, the outer side of the gas filling structure 7 is provided with a heating jacket, and the outer peripheral wall is communicated with the exhaust pipe 10 and the gas injection pipe 9, the gas filling structure 7 is communicated to the primary sampling structure 6 between the gas inlet and the gas outlet of the gas injection pipe 9 to form a convection; further, the heating jacket is electrically connected with the direct current power supply 8; in a preferred embodiment of the present embodiment, the heating jacket is used to directly heat the outer side of the gas filling structure 7 to control the temperature of the internal gas, and under the premise of avoiding steam condensation, the air pressure and temperature of the mixed gas in the filling structure are reduced.

[0044] Specifically, in some embodiments of the present embodiment, the gas filling structure 7 includes an outer cylinder, the outer cylinder is provided with a central flow channel and a plurality of stepped flow channels arranged in a ring outside the central flow channel, the exhaust pipe 10 and the gas injection pipe 9 are both communicated to the plurality of stepped flow channels, the plurality of stepped flow channels are communicated with the central flow channel, the first end of the central flow channel is communicated with the primary sampling structure 6, and the second end of the central flow channel is communicated with the fully developed structure 11.

[0045] It should be noted that when the outer cylinder is heated by the heating jacket, the temperature of the gas filled by the gas injection pipe 9 is gradually increased when flowing through the plurality of stepped flow channels, so that the sampling gas entering the central flow channel of the fully developed structure 11 through the primary sampling structure 6 is intermittently supplemented with air whose temperature gradually decreases, thereby effectively reducing the air pressure and temperature of the sampling gas in the central flow channel of the gas filling structure 7, and reducing the steam partial pressure while gradually reducing the condensation temperature, thereby effectively avoiding steam condensation.

[0046] Specifically, by using the convection type air filling structure, the stage type heating and injection of air can effectively avoid the phenomenon of steam condensation in the gas mixing process, and the design of the radial gas filling structure 7 can exert a force on the aerosol away from the wall surface, thereby solving the problem of aerosol concentration measurement in a pure steam environment, reducing the wall loss of the aerosol in the sampling process, and improving the accuracy of the measurement results.

[0047] The fully developed structure 11 is arranged downstream of the gas filling structure 7 to create a mixed gas environment for the secondary sampling structure to sample and transport sample gas. In some embodiments of the present embodiment, the outer cylinder is provided with a connecting flange 21 at both ends, the gas outlet end of the primary sampling structure 6 and the gas inlet end of the fully developed structure 11 are provided with a connecting flange 21 corresponding to the outer cylinder, and the three are connected in sequence through the connecting flange 21; further, the outer side of the connecting flange 21 is provided with a sealing structure 22 to complete the sealing installation.

[0048] The sampling end of the secondary sampling structure is arranged in the fully developed structure 11 to perform secondary sampling on the mixed gas in the mixed gas environment; the sampling end of the secondary sampling structure in this embodiment also adopts an L-shaped design to ensure that the mixed gas can uniformly flow through the L-shaped sampling end and enter the downstream for measurement. A measurement probe 14 is arranged downstream of the secondary sampling structure to obtain aerosol particle size distribution information, and the measurement probe 14 is in communication with an aerosol measurement host 19 and sends the obtained aerosol particle size distribution information to the aerosol measurement host 19. In some embodiments, a condensate tank 15, a water-gas separation filter 16 and a flow controller 18 are further arranged downstream of the secondary sampling structure in sequence, wherein the flow controller 18 is used to adjust the flow of the gas downstream of the secondary sampling structure to meet the density requirements of the particle size spectrometer, and the flow controller 18 is in communication with a measurement and control host 20; in addition, a drain valve 17 is arranged at the discharge port of the water-gas separation filter 16.

[0049] The exhaust structure 12 is arranged downstream of the fully developed structure 11, and the exhaust pipe 10, the gas injection pipe 9 and the exhaust structure 12 are all provided with flow meters, pressure sensing devices 2, temperature sensing devices 1 and flow regulating valves 4. The flow meters are used to collect the gas flow of the corresponding region, the pressure sensing devices 2 are used to collect the gas pressure data of the corresponding region, and the temperature sensing devices 1 are used to collect the gas temperature of the corresponding region. The flow meters, the pressure sensing devices 2 and the temperature sensing devices 1 are all in communication with the signal input end of the measurement and control host 20 to upload the collected data to the measurement and control host 20. The signal output end of the measurement and control host 20 is in communication with the flow regulating valves 4 to perform self-feedback adjustment on the flow regulating valves 4 of each region according to the received data, so as to realize the functions of uniform temperature reduction, pressure reduction, speed reduction and constant-speed sampling.

[0050] Specifically, by increasing the air charging process, real-time gas flow control can be performed, so that the measurement of aerosol concentration in a steam environment can be realized. In addition, the control logic based on multiple physical parameters such as pressure, temperature and flow can ensure the automatic operation of the system under the target working condition, and realize the constant-speed sampling function of aerosol under a high gas flow speed change range.

[0051] Embodiment 2

[0052] This embodiment further illustrates the gas charging structure 7 based on the technical solution provided in embodiment 1:

[0053] In the embodiment, the first end of the center flow channel is designed as a narrow passage with an inner diameter smaller than that of the second end, and the outlet of the first-stage sampling structure 6 has an inner diameter smaller than that of the first end of the center flow channel, so as to reduce the loss of aerosol on the wall surface; the inlet of the fully developed structure 11 has an inner diameter equal to that of the second end of the center flow channel, so as to create a stable mixed gas environment for stable flow, and to deliver stable sample gas for the aerosol sampling of the second-stage sampling structure.

[0054] Referring to Figure 2 As shown in the figure, the outer cylinder is provided with a plurality of inner cylinders with different outer diameters, and the plurality of inner cylinders are distributed in a stepped manner to form a plurality of stepped flow channels together with the inner wall of the outer cylinder; wherein the inner cylinder with a larger outer diameter is arranged adjacent to the second end of the center flow channel, and the inner cylinder with a smaller outer diameter is arranged adjacent to the first end of the center flow channel; the gas injection pipe 9 is arranged outside the inner cylinder with a larger outer diameter, so as to form a convection between the gas injection pipe 9 and the gas inlet of the center flow channel; the gas exhaust pipe 10 is arranged outside the inner cylinder with a smaller outer diameter, and the gas exhaust pipe 10 is arranged on the same side as the gas injection pipe 9 or distributed on different sides of the outer cylinder, which is not specifically limited here.

[0055] In some preferred embodiments, the inner cylinder is a cylindrical ceramic plate, and a gas flow guide ring rib 25 is sleeved outside the first end of the inner cylinder; a plurality of flow guide holes 26 are formed in the gas flow guide ring rib 25 and the second end of the inner cylinder, for controlling the flow of the gas injected by the gas injection pipe 9 into the center flow channel; the flow guide holes 26 have inclined openings to form inclined flow channels intersecting with the plurality of stepped flow channels and communicating with the center flow channel; the inclined flow channels are located between adjacent inner cylinders, so as to control the flow of the gas injected by the gas injection pipe 9 into the center flow channel while making the gas flow into the center flow channel in an inclined direction, thereby reducing the loss of aerosol caused by airflow collision.

[0056] Further, referring to Figure 3 As shown in the figure, the outer side of the inner cylinder is sleeved with a flow distribution ring rib 24, and a plurality of uniformly distributed flow distribution holes 27 are formed in the flow distribution ring rib 24 to achieve the effect of uniform gas flow. The outer sides of the gas flow guide ring rib 25 and the flow distribution ring rib 24 are abutted on the inner side wall of the outer cylinder through a ring rib support structure 23. Referring to Figure 4 As shown in the figure, the flow distribution holes 27 on the flow distribution ring rib 24 can ensure uniform gas flow, and can control the gas flow of the gas flow guide ring rib 25 corresponding to each level of the inner cylinder and the pressure difference before and after the gas flow guide ring rib 25, together with the flow distribution holes 27, to control the gas flow of each level of the plurality of stepped flow channels into the center flow channel, and to intermittently supplement air with gradually decreasing temperature into the center flow channel when the heating sleeve heats the air inside the plurality of stepped flow channels.

[0057] Embodiment 3

[0058] The embodiment is based on the control method of the aerosol sampling and measuring system suitable for the steam flow system provided in any one of Embodiment 1 to Embodiment 2, see Figure 5 as shown, comprising the following steps:

[0059] Under the premise that the pressure, flow rate and temperature of the gas inside the gas filling structure 7 and the fully developed structure 11 meet the experimental requirements, open the ball valve 5 on the secondary sampling structure;

[0060] Obtain the filling gas flow rate Q1 of the gas injection pipe 9, the exhaust gas flow rate Q2 of the exhaust pipe 10 and the gas flow rate Q4 of the primary sampling structure 6, and calculate the mixed gas proportion of the fully developed structure 11;

[0061] Based on the mixed gas proportion and the mixed gas temperature of the fully developed structure 11, calculate the mixed gas density;

[0062] Based on the mixed gas density, adjust the flow rate of the gas downstream of the secondary sampling structure to meet the density requirement of the particle size spectrometer;

[0063] According to the dilution ratio and the original aerosol particle size distribution, the actual aerosol particle size distribution is calculated, and the dilution ratio is determined according to the flow rate adjustment amount of the gas downstream of the secondary sampling structure.

[0064] In some embodiments of the embodiment, the step of building a scene that meets the experimental requirements is as follows:

[0065] Step 1, obtain the pressure data P0 inside the target measurement environment, the pressure data P1 inside the gas injection pipe 9, the pressure data P2 inside the exhaust pipe 10 and the pressure data P3 inside the fully developed structure 11, determine whether each pressure data meets the first preset condition, if yes, go to step 2, the first preset condition is P1>P1>P0>P3>10kPa;

[0066] If not, generate a first control instruction, which is used to instruct to adjust the opening degree of the flow rate adjusting valve 4 on the gas injection pipe 9, the exhaust pipe 10 and the exhaust structure 12 in sequence;

[0067] Step 2, obtain the filling gas flow rate Q1 of the gas injection pipe 9, the exhaust gas flow rate Q2 of the exhaust pipe 10 and the mixed gas flow rate Q3 of the fully developed structure 11, based on Q1, Q2, Q3, P0 and the gas temperature T0 inside the target measurement environment, calculate the gas flow rate Q4 of the primary sampling structure 6, convert the gas flow rate V2 of the primary sampling structure 6 according to Q4, and determine whether V2 meets the second preset condition, if yes, go to step 3, the second preset condition is that the difference between V2 and the gas flow rate V1 inside the target measurement environment is less than a preset threshold, for example, the preset threshold is set to 5%;

[0068] Otherwise, a second control instruction is generated, which is used to indicate the opening degree of the flow regulating valve 4 on the injection pipe 9;

[0069] In step 3, the temperature T1 of the gas filled in the injection pipe 9, the temperature T2 of the gas discharged from the exhaust pipe 10 and the temperature T3 of the mixed gas in the fully developed structure 11 are obtained, and it is determined whether the temperature data satisfies a third preset condition. If yes, the process goes to step 4. The third preset condition is that T1 and T2 both satisfy the system operation requirement and T3 is within a preset temperature range, for example, 100-150℃.

[0070] If not, a third control instruction is generated, which is used to indicate the heating power of the heating jacket, and the opening degree of the flow regulating valve 4 on the injection pipe 9 and the exhaust pipe 10 is adjusted in sequence when the heating power is out of limit.

[0071] The preferred embodiments of the present application have been described above by way of example only, not intended to limit the present application. Various changes and modifications can be made by those skilled in the art without departing from the spirit and scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An aerosol sampling measurement system suitable for use in a steam flow system, characterised in that, It includes a primary sampling structure (6), a gas filling structure (7), a fully developed structure (11), an emission structure (12), a secondary sampling structure, a measurement and control host (20), and an aerosol measurement host (19); The sampling end of the primary sampling structure (6) is arranged in the target measurement environment. The gas filling structure (7) is arranged downstream of the primary sampling structure (6). A heating jacket is provided on its outer side and an exhaust pipe (10) and an injection pipe (9) are connected to its outer peripheral wall. The gas filling structure (7) is connected to the air inlet of the primary sampling structure (6) and the air outlet of the injection pipe (9) to form convection. The heating jacket is electrically connected to a DC power supply (8). The fully developed structure (11) is arranged downstream of the gas filling structure (7), the sampling end of the secondary sampling structure is arranged in the fully developed structure (11), and a measurement probe (14) is provided downstream of the secondary sampling structure. The measurement probe (14) is communicatively connected to the aerosol measurement host (19). The emission structure (12) is arranged downstream of the fully developed structure (11). The exhaust pipe (10), the air injection pipe (9) and the emission structure (12) are all equipped with a flow meter, a pressure sensing device (2), a temperature sensing device (1) and a flow regulating valve (4). The flow meter, the pressure sensing device (2) and the temperature sensing device (1) are all connected to the signal input terminal of the measurement and control host (20). The signal output terminal of the measurement and control host (20) is connected to the flow regulating valve (4). The gas filling structure (7) includes an outer cylinder, a central flow channel and several inner cylinders with different outer diameters inside the outer cylinder. The several inner cylinders are distributed in a stepped manner, forming a multi-level stepped flow channel together with the inner wall of the outer cylinder. The multi-level stepped flow channel is distributed in a ring shape outside the central flow channel. The exhaust pipe (10) and the gas injection pipe (9) are both connected to the multi-level stepped flow channel. The multi-level stepped flow channel is connected to the central flow channel. The first end of the central flow channel is connected to the first-level sampling structure (6), and the second end of the central flow channel is connected to the fully developed structure (11).

2. The aerosol sampling measurement system suitable for use in a steam flow system of claim 1, wherein, The sampling ends of the primary sampling structure (6) and the secondary sampling structure are both L-shaped.

3. The aerosol sampling measurement system suitable for use in a steam flow system of claim 1, wherein, Downstream of the secondary sampling structure, a condensate tank (15) and a steam-water separator (16) are also installed in sequence.

4. The aerosol sampling measurement system suitable for use in a steam flow system of claim 1, wherein, The inner diameter of the first end of the central flow channel is smaller than the inner diameter of its second end, the inner diameter of the outlet of the first-stage sampling structure (6) is smaller than the inner diameter of the first end of the central flow channel, and the inner diameter of the inlet of the fully developed structure (11) is equal to the inner diameter of the second end of the central flow channel.

5. The aerosol sampling measurement system suitable for use in a steam flow system of claim 4, wherein, The inner cylinder with a larger outer diameter is arranged at the second end near the central flow channel, and the inner cylinder with a smaller outer diameter is arranged at the first end near the central flow channel. The air injection pipe (9) is arranged on the outside of the inner cylinder with a larger outer diameter, and the exhaust pipe (10) is arranged on the outside of the inner cylinder with a smaller outer diameter.

6. The aerosol sampling measurement system suitable for use in a steam flow system of claim 5, wherein, A gas guide ring rib (25) is sleeved on the outer side of the first end of the inner cylinder. A plurality of flow guide holes (26) are opened on both the gas guide ring rib (25) and the second end of the inner cylinder. The flow guide holes (26) have oblique openings to form oblique flow channels that intersect with the multi-stage stepped flow channels and connect to the central flow channel. The oblique flow channels are located between adjacent inner cylinders.

7. The aerosol sampling measurement system suitable for use in a steam flow system of claim 5, wherein, The outer side of the inner cylinder is fitted with a flow distribution ring rib (24), and the flow distribution ring rib (24) is provided with a number of evenly distributed flow distribution holes (27).

8. A control method for an aerosol sampling and measurement system suitable for use in a steam flow system as claimed in any one of claims 1 to 7, characterized in that, Includes the following steps: Provided that the pressure, flow rate and temperature of the gas inside the gas filling structure (7) and the fully developed structure (11) meet the experimental requirements, the ball valve (5) on the secondary sampling structure is opened; Obtain the gas flow rate Q1 of the gas injection pipe (9), the gas flow rate Q2 of the gas discharge pipe (10) and the gas flow rate Q4 of the first-stage sampling structure (6), and calculate the mixed gas ratio of the fully developed structure (11). The density of the mixed gas is calculated based on the mixed gas ratio and mixed gas temperature of the fully developed structure (11); The flow rate of the downstream gas in the secondary sampling structure is adjusted based on the density of the mixed gas to meet the density requirements of the particle size analyzer. The actual aerosol particle size distribution is calculated based on the dilution ratio and the original aerosol particle size distribution. The dilution ratio is determined based on the flow rate adjustment of the gas downstream of the secondary sampling structure.

9. The control method for an aerosol sampling and measurement system suitable for a vapor flow system as described in claim 8, characterized in that, The steps to build a scenario that meets the experimental requirements are as follows: Step 1: Obtain the pressure data P0 inside the target measurement environment, the pressure data P1 inside the air injection pipe (9), the pressure data P2 inside the exhaust pipe (10), and the pressure data P3 inside the fully developed structure (11). Determine whether each pressure data meets the first preset condition. If so, proceed to step 2. The first preset condition is P1 > P2 > P0 > P3 > 10 kPa. If not, generate a first control command, which is used to instruct the opening degree of the flow regulating valve (4) on the air injection pipe (9), the exhaust pipe (10) and the discharge structure (12) in sequence; Step 2: Obtain the gas flow rate Q1 of the gas injection pipe (9), the gas flow rate Q2 of the gas discharge pipe (10), and the mixed gas flow rate Q3 of the fully developed structure (11). Based on Q1, Q2, Q3, P0 and the gas temperature T0 inside the target measurement environment, calculate the gas flow rate Q4 of the primary sampling structure (6). Calculate the gas velocity V2 of the primary sampling structure (6) based on Q4. Determine whether V2 meets the second preset condition. If so, proceed to step 3. The second preset condition is that the difference between V2 and the gas velocity V1 inside the target measurement environment is less than a preset threshold. Otherwise, a second control command is generated, which is used to instruct the opening degree of the flow regulating valve (4) on the regulating discharge structure (12); Step 3: Obtain the gas temperature T1 of the gas injection pipe (9), the gas temperature T2 of the gas discharge pipe (10), and the mixed gas temperature T3 of the fully developed structure (11). Determine whether each temperature data meets the third preset condition. If so, proceed to step 4. The third preset condition is that both T1 and T2 meet the system operation requirements and T3 is within the preset temperature range. If not, a third control command is generated, which is used to indicate the adjustment of the heating power of the heating jacket, and when the heating power exceeds the limit, the opening of the flow regulating valve (4) on the air injection pipe (9) and the exhaust pipe (10) is adjusted in sequence.

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