Multifunctional sodium-cooled fast reactor debris bed simulation device and light refraction compensation measurement method

Abstract

A multifunctional sodium-cooled fast reactor debris bed simulation device and a light refraction compensation measurement method, comprising: an experimental device support platform and a retractable support platform arranged thereon, a data acquisition system, a debris bed particle release system, a dry particle collection system, a visual debris bed particle container, a light refraction compensation container, a debris bed heating and gas injection mixing system, wherein: the light refraction compensation container is located outside the visual debris bed particle container and is arranged as a whole in the retractable support platform, the debris bed particle release system is located above the retractable support platform and directly faces the visual debris bed particle container, the debris bed heating system and the dry particle collection system are arranged in sequence below the experimental device support platform, and the debris bed heating system is connected to the visual debris bed particle container, and the dry particle collection system is connected to the gas injection system. The present invention provides model support for the development and verification of large-scale safety analysis programs, accurately extracts the angle data of the simulation device through light refraction compensation measurement, and can provide a correction scheme for the observation and detection of actual industrial cylindrical containers.

Description

Technical Field

[0001] The present invention relates to a technology in the field of nuclear reactor control, in particular to a sodium-cooled fast reactor debris bed simulation device and a light refraction compensation measurement method for simulating the continuous process of the entire debris bed formation, leveling and drying. Background Art

[0002] The fourth generation nuclear reactor has the advantages of consuming depleted uranium to achieve fuel proliferation and transmutation of long-life radioactive waste, making the sodium-cooled fast reactor a promising fourth generation reactor type. When a core disintegration accident occurs in a sodium-cooled fast reactor, the core fuel breaks and melts, interacts with the coolant, solidifies and disperses into granular fragments, and the fragments are deposited on the surface of the lower chamber structure to form a debris bed. The coolant in the bed boils under the action of the decay heat of the debris bed particles, causing the molten particles to migrate under the combined action of steam and liquid convection, causing the shape of the debris bed to change, thereby affecting the coolability of the debris bed. Therefore, studying the formation and migration mechanism of the debris bed in the sodium-cooled fast reactor disintegration accident and the coolability of the debris bed is conducive to the formulation and response of the severe accident management guidelines for sodium-cooled fast reactors. In the existing technology, most of the debris beds are artificially built in the process of simulating the migration and coolability of the debris bed of the sodium-cooled fast reactor. At this time, the porosity distribution of the debris bed is quite different from the porosity distribution of the actual reactor, and there is a considerable deviation between the formation and coolability results and the actual reactor situation. This is a scientific problem that needs to be solved urgently. Therefore, it is necessary to study the formation, migration, and coolability of the debris bed. In order to study the formation, migration, and overall coolability of the debris bed, it is necessary to design an effective sodium-cooled fast reactor simulation device that can meet the overall behavior of the formation and migration of the debris bed, the measurement of the coolability dry heat flux density, and the research of the pool velocity field, so as to explore the influence of various factors such as particle size, particle material, particle shape, porosity, debris bed height, water depth, release aperture, and release height on the formation, migration behavior, and coolability of the debris bed; in addition, a set of light refraction compensation measurement methods are proposed for the error problem caused by light refraction in the simulation device. Summary of the invention

[0003] Aiming at the problems that the prior art cannot track the subsequent formation and leveling process after the melt is broken into fragments, cannot simulate the overall characteristic research of the formation and leveling of the fragment bed, simulate the generation of decay heat, the light refraction of the simulation device brings about the measurement angle deviation, and the discharged debris bed particles are wet particles, which will interfere with the subsequent experimental results, the present invention proposes a multifunctional sodium-cooled fast reactor debris bed simulation device and a light refraction compensation measurement method, which can not only continuously simulate the formation and leveling behavior of the sodium-cooled fast reactor debris bed under accident conditions, but also measure the dry-up heat flux density of the debris bed, simulate boiling conditions by controlling the heating power and the gas injection rate, conduct continuous experiments on the formation and leveling of the debris bed, effectively realize the formation and leveling behavior of the sodium-cooled fast reactor debris bed, and can also measure the dry-up heat flux density of the debris bed by controlling the power, so as to provide a method for studying the formation and leveling mechanism of the debris bed, provide data support for the debris bed dry-up phenomenon, provide model support for the development and verification of large-scale safety analysis programs, accurately extract the angle data of the simulation device through light refraction compensation measurement, and provide a correction scheme for the observation and detection of actual industrial cylindrical containers.

[0004] The present invention is achieved through the following technical solutions:

[0005] The invention relates to a multifunctional sodium-cooled fast reactor debris bed simulation device, comprising: an experimental device support platform and a retractable support platform arranged thereon, a data acquisition system, a debris bed particle release system, a dry particle collection system, a visual debris bed particle container, a light refraction compensation container, a debris bed heating and gas injection mixing system, wherein: the light refraction compensation container is located outside the visual debris bed particle container and is arranged as a whole in the retractable support platform, the debris bed particle release system is located above the retractable support platform and directly faces the visual debris bed particle container, the debris bed heating system and the dry particle collection system are arranged in sequence below the experimental device support platform, the debris bed heating system is connected to the visual debris bed particle container, and the dry particle collection system is connected to the gas injection system.

[0006] The present invention relates to a light refraction compensation measurement method based on the light refraction compensation container. The method observes from two different directions and constructs two light refraction linear equations, solves and determines the position of particles in the container, and corrects the refraction distortion of the cylindrical container image through the light refraction compensation container, thereby accurately simulating and evaluating the formation and leveling process of the sodium-cooled fast reactor debris bed.

[0007] The two light refraction straight line equations are: When the center of the tube is selected as the origin of the Cartesian coordinate system, the particle position is Where: a represents the distance from the center of the cylindrical container to the perpendicular bisector of the ray container, represents the angle between the perpendicular bisector and the horizontal axis, θ represents the angle between the line connecting any point on the ray to the origin and the horizontal axis, r is the inner diameter, that is, RA, and Ω is the angle between the ray and the line connecting the camera and the center of the container.

[0008] The correction refers to: making corrections to the particle position and angle based on the geometric relationship according to the actual position and the observed position.

[0009] Technical Effects

[0010] The present invention uses a multifunctional sodium-cooled fast reactor debris bed simulation device to achieve research on the overall process of debris bed formation, migration and coolability phenomena and accurate measurement of debris bed migration angle and dry-up heat flux density that is more in line with the actual accident situation; a decay heat simulation group and a gas injection group are used to quantitatively combine to achieve simulation of non-condensable gas after the sodium-cooled fast reactor melts through the containment floor; the heating plate section of the air inlet pipeline is filled with debris bed particles to facilitate uniform gas injection and heat conduction; a method for discharging and spiral drying debris bed particles is proposed to achieve drying treatment and preservation of debris particles; a light refraction compensation measurement method is proposed to achieve accurate measurement of the simulation device. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the structure of the present invention;

[0012] Figure 2 This is a schematic diagram of the debris bed heating system;

[0013] Figure 3 and Figure 4 This is a schematic diagram of optical compensation correction;

[0014] Figure 5 and Figure 6 It is a schematic diagram of the effect of the embodiment;

[0015] Figure 7 and Figure 8 This is a schematic diagram of the drying effect of the spiral heating pipeline;

[0016] Fig. 9 It is a schematic diagram of the drying experiment data of the embodiment;

[0017] In the figure: 1 experimental device support platform, 2 dry particle collection system, 3 drainage pipeline, 4 air intake pipeline, 5 retractable release device support platform, 6 light refraction compensation container, 7 visualization debris bed particle container, 8 release container, 9 lifting rod, 10 lifting body, 11 ball screw, 12 motor, 13 debris bed heating system, 14 spiral heating pipeline. DETAILED DESCRIPTION

[0018] like Figure 1As shown, this embodiment relates to a multifunctional sodium-cooled fast reactor debris bed simulation device with a correction function, including: an experimental device support platform 1 and a retractable support platform 5 arranged thereon, a data acquisition system, a debris bed particle release system, a dry particle collection system 2, a visual debris bed particle container 7, a light refraction compensation container 6, a debris bed heating system 13 and a gas injection system 4, wherein: the light refraction compensation container 6 is located outside the visual debris bed particle container 7 and is entirely arranged in the retractable support platform 5, the debris bed particle release system is located above the retractable support platform 5 and directly faces the visual debris bed particle container 7, the debris bed heating system 13 and the dry particle collection system 2 are sequentially arranged below the experimental device support platform 1, and the debris bed heating system 13 is connected to the visual debris bed particle container 7, and the dry particle collection system 2 is connected to the gas injection system 4.

[0019] The experimental support platform 1 is a channel steel structure that can support a large weight and is used to support the visual debris bed particle container 7 and the light refraction compensation container 6 as well as the weight. A staircase structure is also provided to facilitate loading and unloading of debris bed simulation particles.

[0020] The dry particle collection system 2 comprises a debris bed particle collection box and a spiral heating pipe 14. The interior of the pipe comprises a spiral channel, which is welded on the main shaft. The main shaft can be rotated manually or connected to an adjustable speed motor to rotate and discharge the debris bed particles. The outside of the channel is wrapped with a resistance wire for heating. At the same time, when discharging the debris bed particles, the air injection system can inject hot air through the filter to accelerate the drying of the debris bed particles, thereby allowing the experimental debris bed particles to dry quickly, facilitating storage and preventing wet particles from interfering with the next experiment.

[0021] The retractable support platform 5 is a stainless steel structure, used to support the debris bed particle release system. The support platform is provided with a retractable structure, which can change the release height.

[0022] The light refraction compensation container 6 and the visualization debris bed particle container 7 are both made of transparent materials, including but not limited to tempered glass and acrylic materials. The container shape can be cylindrical, rectangular or even irregular, wherein the cylindrical and irregular shapes can be corrected using the light refraction compensation container. The contained particles include but are not limited to glass, stainless steel, aluminum oxide, lead, uranium dioxide, and gravel; the contained liquids include but are not limited to water, oil, and alcohol.

[0023] The liquid contained in the light refraction compensation container 6 should also be consistent with the liquid contained in 7 to facilitate light refraction compensation.

[0024] The debris bed particle release system comprises: a release container 8, a lifting rod 9 arranged therein, and a lifting body 10, a ball screw 11 and a motor 12 connected to the lifting rod 9 in sequence, wherein: the tail end of the lifting rod 9 is connected to the ball screw lever and the lifting rod is lifted by the ball screw driven by the motor.

[0025] The release container 8 is preferably a stainless steel cylindrical funnel, and stainless steel funnels of different calibers can be processed according to requirements.

[0026] The lifting rod 9 is preferably a stainless steel cone-head lifting rod that matches the stainless steel cylindrical funnel.

[0027] The ball screw 11 can reliably lift and release the experimental particles when the release container is large in volume and contains a large number of experimental particles.

[0028] like Figure 2 As shown, the debris bed heating system 13 includes: a stainless steel plate 131, a heating plate 132, an insulating plate 133, a thermocouple 134 and a control cabinet 135, wherein: the thermocouple is arranged on the stainless steel plate 131, the heating plate 132 adopts a customized central opening structure and is connected to the stainless steel plate 131, and the gas injection pipeline can be inserted in the center; by using it in combination with the thermocouple in the slot of the stainless steel plate, the accurate real-time heat input to the debris bed is obtained by using the thermocouple temperature difference and distance calculation.

[0029] The stainless steel plate 131 is provided with slots, and a plurality of thermocouples 134 are arranged at different positions from the center of the circle. The spacing between each pair of thermocouples is δ, and the input power Where: i represents the thermocouple number, qi represents the heat input calculated for each pair of thermocouples, λ represents the thermal conductivity of the stainless steel plate, δ represents the distance between a pair of thermocouples, ΔT i represents the temperature difference between the i-th pair of thermocouples; q in represents the cross-sectional heat input, Vp represents the volume of the fragment bed, ε represents the porosity, and A represents the cross-sectional area.

[0030] The heating plate is provided with a resistance wire to make the heating plate heat evenly, and an external control cabinet can be connected to detect the power and temperature of the heating plate.

[0031] The insulating board may be, but is not limited to, an asbestos board, an insulating rubber board, or an insulating rubber pad.

[0032] The gas injection system 4 includes: a gas cylinder 41 with built-in simulated gas, a gas exhaust 42, a flow meter 43, a valve 44 and a pipeline 45, wherein: a filter is arranged at the connection with the spiral heating pipeline 14 to prevent particles from entering the gas injection pipeline and to inject hot gas to accelerate particle drying when the particles are collected.

[0033] The data acquisition system comprises: a visualized velocity field acquisition system, a frequency-modulated high-speed camera, a temperature acquisition system, a power acquisition system, a flow acquisition system and a pressure difference acquisition system, wherein: the visualized image acquisition system acquires velocity field image information of the formation and leveling process of the debris bed and outputs it to the PIV post-processing software for velocity field post-processing, the high-speed camera acquires angle image information of formation and leveling and outputs it to the computer processing platform, the temperature acquisition system respectively acquires the thermocouple temperature of the heating plate, the water temperature of the debris bed, and the temperature of the debris bed and outputs them to the NI data acquisition system, the power acquisition system acquires the heating power of the heating plate and outputs it to the control cabinet instrument, the flow acquisition system acquires the gas injection flow and the water injection flow and outputs them to the NI data acquisition system, and the pressure difference acquisition system acquires the pressure and pressure difference information between various parts of the debris bed and outputs it to the NI data acquisition system.

[0034] like Figure 3 , Figure 4 As shown, this embodiment relates to a light refraction compensation measurement method based on the light refraction compensation container, comprising the following steps:

[0035] Step 1: Fill the visualized debris bed particle container with liquid to a suitable height, and fill the light refraction compensation container with the same liquid at a height higher than the debris bed particle container;

[0036] Step 2: Adjust the height of the retractable support platform to a suitable position, select a suitable release container, and control the ball screw through the control cabinet to lower the lifting rod position to the lowest position;

[0037] Step 3: Place the particles used in the experiment into the release container. For mixed particle release tests, particles of different diameters should be mixed evenly in advance;

[0038] Step 4: Connect the visualization image acquisition system, temperature acquisition system, power acquisition system, and pressure difference acquisition system to the experimental equipment and debug them normally;

[0039] Step 5: Set the air inlet line flow rate to the preset parameters or the heating plate power to the expected parameters to simulate the boiling effect caused by decay heat; or use the air inlet line and the heating plate at the same time to simulate the boiling caused by decay heat and the influence of non-condensable gases on the behavior of the debris bed in the late stage of a severe accident.

[0040] Step 6: Start the data acquisition system to collect data, start the electric control cabinet to lift the lifting rod to release the particles, and open the air intake line valve or the heating plate switch for heating.

[0041] Step 7: First collect the experimental data of the debris bed formation process. After the particles are completely released, the debris bed formation process turns into a debris bed migration process, and the air intake flow rate and heating plate power are adjusted to complete the subsequent debris bed migration process.

[0042] Step 8: Drain the liquid in the light refraction compensation container, continuously increase the power of the heating plate, and perform angle analysis of the forming and leveling process and dry-up heat flux density analysis based on the detection data, including:

[0043] 8.1) If Figure 3 and Figure 4 As shown, take any point P on the debris bed to form the inclination angle, and determine the actual position Q corresponding to the point, that is, to obtain the real inclination angle. The correction process of the coordinates of point P is the process of determining the position of Q, specifically: OQ = OD*tan(β3)+CD. In ΔOED, ED can be obtained, CD = ED-EC; CD = L*tan(α1-β1+α2)-EC; in ΔEBC, the sine theorem can be used to obtain In ΔEOD, BE = OE - OB; Among them: point O is the origin of the cylindrical container, point P is an arbitrary point on the inclination angle, Q is the true position of point P after correction, point A is the intersection of the observation ray of point P and the inner wall of the cylindrical container, point B is the intersection of the line connecting the origin of the cylinder and point A and the outer wall of the cylindrical container, point C is the intersection of the observation ray of point P with the correction container after refraction through the cylindrical container, and point D is the intersection of the horizontal line and the correction container.

[0044] 8.2) If Figure 5 and Figure 6 As shown, when the debris bed dries up, the temperatures corresponding to the current eight pairs of thermocouples 134 are recorded and the heat flux density is calculated. It is the heat flux density of debris bed drying.

[0045] After specific actual experiments, the funnel hole with a funnel diameter of 5 cm, the height of the funnel is 10 cm from the top of the container, the debris bed is made of 304 stainless steel, the container liquid is distilled water, and the particle diameters are 1 mm, 2 mm, and 3 mm. Under the specific environmental settings, the stainless steel particles are released into the transparent container, and the experimental pictures that can be obtained are: Figure 5 , Figure 6 , the angle formed is 25°, and the debris bed leveling experiment can be completed; for the drying experiment data such as Fig. 9 As shown, the dry-up heat flux data is compared with the existing Lipinski prediction model. The experimental data has a small error with the Lipinski model, which is accurate and reliable. In summary, this experimental device can complete the debris bed formation, migration and dry-up experiments, and can accurately measure the debris bed formation and migration angle changes and dry-up heat flux.

[0046] Compared with the existing technology, the device can achieve accurate measurement of the multi-physical phenomena of debris bed formation and migration behavior and dry-down heat flux density; through the arrangement of multiple thermocouples, it can realize the quantitative input of heating power and the accurate acquisition of dry-down heat flux density; through the use of heating plates and gas injection equipment, it can simulate the influence of different boiling modes on debris bed formation and migration, and simulate the influence of non-condensable gas on dry-down heat flux density; through the combination of debris bed particle collection system and gas injection system, the particles can be quickly dried and collected.

[0047] The above-mentioned specific implementation can be partially adjusted in different ways by those skilled in the art without departing from the principle and purpose of the present invention. The protection scope of the present invention shall be based on the claims and shall not be limited by the above-mentioned specific implementation. Each implementation scheme within its scope shall be subject to the constraints of the present invention.

Claims

1. A light refraction compensation measurement method based on a multifunctional sodium-cooled fast reactor debris bed simulator, characterized in that: The simulation device comprises: an experimental device support platform and a retractable support platform arranged thereon, a data acquisition system, a debris bed particle release system, a dry particle collection system, a visual debris bed particle container, a light refraction compensation container, a debris bed heating and gas injection mixing system, wherein: the light refraction compensation container is located outside the visual debris bed particle container and is entirely arranged in the retractable support platform, the debris bed particle release system is located above the retractable support platform and directly faces the visual debris bed particle container, the debris bed heating system and the dry particle collection system are sequentially arranged below the experimental device support platform, and the debris bed heating system is connected to the visual debris bed particle container, and the dry particle collection system is connected to the gas injection mixing system; The debris bed heating system comprises: a stainless steel plate, a heating plate, an insulating plate, a thermocouple and a control cabinet, wherein: the thermocouple is arranged on the stainless steel plate, the heating plate adopts a customized central opening structure and is connected to the stainless steel plate, and the gas injection pipeline is inserted in the center; by combining with the thermocouple in the slot of the stainless steel plate, the accurate real-time heat input to the debris bed is obtained by using the temperature difference and distance of the thermocouple; The light refraction compensation measurement refers to: observing from two different directions and constructing two light refraction linear equations, solving and determining the position of particles in the container and correcting the refraction distortion of the cylindrical container image through the light refraction compensation container, so as to accurately simulate and evaluate the formation and leveling process of the sodium-cooled fast reactor debris bed.

2. The method for measuring light refraction compensation according to claim 1, characterized in that: The dry particle collection system comprises a debris bed particle collection box and a spiral heating pipe. The interior of the pipe comprises a spiral channel, which is welded on the main shaft. The main shaft is rotated manually or connected to an adjustable speed motor for rotation to discharge the debris bed particles. The outside of the channel is wrapped with a resistance wire for heating. At the same time, when discharging the debris bed particles, the air injection mixing system injects hot air through a filter to accelerate the drying of the debris bed particles, thereby allowing the experimental debris bed particles to dry quickly, facilitating storage and preventing wet particles from interfering with the next experiment.

3. The light refraction compensation measurement method according to claim 1, characterized in that: The light refraction compensation container and the visualized debris bed particle container are both made of transparent materials. The container shape is cylindrical or irregular so as to be corrected by the light refraction compensation container. The particles contained include glass, stainless steel, aluminum oxide, lead, uranium dioxide, and gravel. The liquids contained include water, oil, and alcohol.

4. The light refraction compensation measurement method according to claim 1, characterized in that: The debris bed particle release system comprises: a release container, a lifting rod arranged therein, and a lifting body, a ball screw and a motor connected to the lifting rod in sequence, wherein: the tail of the lifting rod is connected to the ball screw lever and the motor drives the ball screw to lift the lifting rod.

5. The light refraction compensation measurement method according to claim 1, characterized in that: The gas injection and mixing system includes: a gas cylinder with built-in simulated gas, a gas exhaust, a flow meter, a valve and a pipeline, wherein: a filter is arranged at the connection with the spiral heating pipeline to prevent particles from entering the gas injection pipeline and hot gas is injected when the particles are collected to accelerate the drying of the particles.

6. The light refraction compensation measurement method according to claim 1, characterized in that: The data acquisition system comprises: a visualized velocity field acquisition system, a frequency-modulated high-speed camera, a temperature acquisition system, a power acquisition system, a flow acquisition system and a pressure difference acquisition system, wherein: the visualized image acquisition system acquires velocity field image information of the formation and leveling process of the debris bed and outputs it to the PIV post-processing software for velocity field post-processing, the high-speed camera acquires angle image information of formation and leveling and outputs it to the computer processing platform, the temperature acquisition system respectively acquires the thermocouple temperature of the heating plate, the water temperature of the debris bed, and the temperature of the debris bed and outputs them to the NI data acquisition system, the power acquisition system acquires the heating power of the heating plate and outputs it to the control cabinet instrument, the flow acquisition system acquires the gas injection flow and the water injection flow and outputs them to the NI data acquisition system, and the pressure difference acquisition system acquires the pressure and pressure difference information between various parts of the debris bed and outputs it to the NI data acquisition system.

7. The light refraction compensation measurement method according to claim 1, characterized in that: The two light refraction straight line equations are: When the center of the tube is selected as the origin of the Cartesian coordinate system, the particle position is Where: a represents the distance from the center of the cylindrical container to the perpendicular bisector of the ray container, represents the angle between the perpendicular bisector and the horizontal axis, θ represents the angle between the line connecting any point on the ray to the origin and the horizontal axis, r is the inner diameter, that is, RA, and Ω is the angle between the ray and the line connecting the camera and the center of the container.

8. The light refraction compensation measurement method according to claim 1, characterized in that: The observations specifically include: Step 1: Fill the visualized debris bed particle container with liquid to a suitable height, and fill the light refraction compensation container with the same liquid at a height higher than the debris bed particle container; Step 2: Adjust the height of the retractable support platform to a suitable position, select a suitable release container, and control the ball screw through the control cabinet to lower the lifting rod position to the lowest position; Step 3: Place the particles used in the experiment into the release container. For mixed particle release tests, particles of different diameters should be mixed evenly in advance; Step 4: Connect the visualization image acquisition system, temperature acquisition system, power acquisition system, and pressure difference acquisition system to the experimental equipment and debug them normally; Step 5: Set the air inlet line flow rate to a predetermined parameter or the heating plate power to an expected parameter to simulate the boiling effect caused by decay heat; or use the air inlet line and the heating plate at the same time to simulate the boiling caused by decay heat and the effect of non-condensable gas on the behavior of the debris bed in the late stage of a severe accident; Step 6: Start the data acquisition system to collect data, start the electric control cabinet to lift the lifting rod to release the particles, and open the air intake line valve or the heating plate switch for heating; Step 7: First collect the experimental data of the debris bed formation process. After the particles are completely released, the debris bed formation process turns into a debris bed migration process, and the air intake flow rate and heating plate power are adjusted to complete the subsequent debris bed migration process.

9. The light refraction compensation measurement method according to claim 8, characterized in that: The simulation and evaluation refers to: draining the liquid in the light refraction compensation container, continuously increasing the power of the heating plate, and performing angle analysis of the forming and leveling process and dry-up heat flux density analysis based on the detection data, specifically including: 8.1) Take any point P on the debris bed to form the inclination angle, and determine the actual position Q corresponding to the point, that is, to obtain the real inclination angle. The correction process of the coordinates of point P is the process of determining the position of Q, specifically: OQ = OD*tan(β3)+CD. In △OED, ED can be obtained, CD = ED-EC; CD = L*tan(α1-β1+α2)-EC; in △EBC, the sine theorem can be obtained In △EOD, BE=OE-OB; Among them: point O is the origin of the cylindrical container, point P is an arbitrary point on the tilt angle, Q is the true position of point P after correction, point A is the intersection of the observation ray of point P and the inner wall of the cylindrical container, point B is the intersection of the line connecting the origin of the cylinder and point A and the outer wall of the cylindrical container, point C is the intersection of the observation ray of point P and the correction container after refraction by the cylindrical container, and point D is the intersection of the horizontal line and the correction container; 8.2) When the debris bed dries up, record the temperatures of the eight pairs of thermocouples and calculate the heat flux density It is the heat flux density of debris bed drying.

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