CN108227796B - Multi-field coupling experimental device for bulk grain stack - Google Patents
Multi-field coupling experimental device for bulk grain stack Download PDFInfo
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- CN108227796B CN108227796B CN201810141040.6A CN201810141040A CN108227796B CN 108227796 B CN108227796 B CN 108227796B CN 201810141040 A CN201810141040 A CN 201810141040A CN 108227796 B CN108227796 B CN 108227796B
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- Y02A40/10—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production in agriculture
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Abstract
The invention discloses a bulk grain pile multi-field coupling experimental device, which comprises an upper opening model box body, wherein temperature and humidity sensors are arranged in the box body, and observation windows are arranged on the front side wall and the rear side wall of the model box body; the left side wall and the right side wall of the box body are of cavity structures, circulating water pipes communicated with an external high-temperature control system and an external low-temperature control system are respectively arranged in the cavity structures, and a servo flexible loading control system is arranged at the opening of the box body: the system comprises a cover plate buckled at the opening of the box body, a pressure air bag is horizontally arranged below the cover plate, and a pressure sensor is arranged under the air bag. The invention has simple structure, convenient operation and high accuracy, adopts the model box filled with grains as a specific position in the granary, and combines a plurality of measures through a pressure control system, a temperature control system, a ventilation control system, a visual window, an infrared thermal digital image and a liquid drop method, thereby realizing the research on the multi-field coupling rule of a pressure field, a temperature field, a humidity field and a micro-air flow field in a grain pile.
Description
Technical Field
The invention relates to measurement of a large-scale stored grain pile, in particular to a one-dimensional multi-field coupling experimental device for a bulk grain pile.
Background
The problem of safe storage of grains is related to national life and national security. Among all the bins for grain storage, the horizontal warehouse is widely used due to the characteristics of large warehouse capacity, low manufacturing cost, convenience in grain inlet and outlet and the like. The granary type barn built in the national reserved granary at present is more than 85% of the granary type barns of bulk grains, so that the grain storage safety of the barn is particularly important.
According to investigation of grain and agriculture organizations of united nations, the loss of grain storage is 3% due to mildew and 5% due to insect damage every year worldwide, and the total loss is 8%. In recent years, the grain yield of China is continuously improved, annual grain yield exceeds 6 hundred million tons, national grain inventory is in a high history, part of main production areas have extremely outstanding storage contradiction, the quality safety difficulty of the stored grains is high, and the postpartum loss quantity of the grains is remarkable.
Related researches show that in a large-volume grain pile stored in a granary, a plurality of physical fields such as a pressure field, a temperature field, a humidity field, a micro-air flow field and the like exist, close relativity, namely coupling relation exists among physical factors, and the physical fields are important factors affecting the quality of stored grains and even causing mildew and insect damage of the grains. Therefore, a grain stack multi-physical field coupling model is constructed, the state change rules among a grain stack pressure field, a temperature field, a humidity field, a micro air flow field and other multi-physical factors are controlled, grain storage is guided, grain insect damage and mildew are reduced, and grain storage quality is guaranteed to be one of the main problems which need to be solved urgently.
In the grain storage process, heating, mildew and insect damage of grain piles can be caused due to the external environment, the self respiration of grains and the like, and a large amount of grains can be deteriorated if not treated in time. Therefore, the temperature and humidity of grains are controlled in the granary through mechanical ventilation, so that phenomena such as heating and mildew of grain piles are inhibited, and the porosity of the grain piles is a key parameter for researching the mechanical ventilation of the granary. The grain pile porosity refers to the ratio of the pore volume in the grain pile to the total volume of the grain pile. With the increase of the height of the grain and the increase of the pressure of the grain pile, the grains are compacted, the grain bulk density is increased, the porosity is reduced, the ventilation resistance is increased, and the ideal cooling and dehumidifying effects are not easy to obtain in a short time. Therefore, researching the relation between the grain pile pressure and the porosity has important significance for determining reasonable ventilation indexes and reducing grain storage loss.
At present, the research on multi-field coupling of a grain pile is mainly focused on coupling between two physical fields of the grain pile, such as numerical simulation research on heat and humidity transfer of the grain pile, numerical simulation research on flow-force of the grain pile, simulation experiment on condensation of the grain pile and the like, the research on mannitoba university in Canada is mainly focused on modeling of a grain storage ecological system, hot spots and safe storage conditions of the grain pile, air flow of the grain pile, the relation among migration, distribution, sampling and trapping of pests in the grain, evaluation of grain storage quality by image processing technology and the like, and the research on the coupling rules of a grain pile pressure field, a temperature field, a humidity field and a micro-air flow field is less. The national institute of food science builds a wheat grain stack dewing simulation experiment platform, and mainly aims to study the temperature, the water distribution and the change process in the grain storage process, but only considers the temperature and the water of the grain stack, and does not consider the influence of the non-uniformity of the grain stack space pressure field distribution caused by the gravity of the bulk grain stack on the grain storage.
In the storage process of the grain pile of the large-volume granary, the porosity of the grain pile is changed under the action of self gravity due to the difference of the grain loading heights, and the change of the porosity of the grain pile can influence the micro-airflow and the moisture migration of the grain pile, so that the non-uniformity of the temperature and the humidity distribution of the grain pile is caused.
In summer, the temperature around the warehouse wall is gradually increased under the action of solar radiation, and the grain pile forms a hot Pi Leng core state with hot periphery and cold middle due to the influence of poor heat conduction characteristics of grains, so that a stable field of the granary is formed. The energy heat points to the grain pile from the periphery of the bin wall, and the water and the energy heat transfer direction are the same according to the water transfer principle, namely the high temperature of the surface layer enables the water to migrate to the inner layer, so that the temperature of the surface layer is increased, and the water is reduced. The high-temperature and high-humidity environment is favorable for the growth of microorganisms and pests, and the grains in the high-temperature and low-humidity environment cannot be destroyed. Because the intermediate core region is large, the moisture migrating to the core is relatively small, i.e., a low temperature and low humidity environment, and will not be derived from microorganisms. The periphery is high in temperature and low in humidity, the inner layer is low in temperature and low in humidity, and micro-airflow circulation is formed under the action of the temperature difference between the inner layer and the outer layer, and the state is a stable state.
In winter, the outside environment temperature is lower, the energy heat flow direction is opposite to summer, but energy heat transfer to the bin wall is carried out through heat exchange and is dissipated, moisture is transferred to the bin wall and is retained due to isolation of the bin wall, and dew condensation is formed along with seasonal change and moisture accumulation, so that grain mildew is caused. The proper temperature and humidity can promote the propagation of microorganisms, strengthen the manual intervention and the grain storage regulation, and can better regulate the temperature and humidity in the bin so as to inhibit the growth of microorganisms.
The same phenomenon is true of micro-air flow, and by transpiration, water moves upwards, and cold air is condensed on the upper part of the grain pile, and the cabin wall is condensed on the cabin wall, namely the phenomenon of roof and wall accumulation. However, unstable states such as dew formation and mildew and the like are not absolutely generated in the storage process of the grain stack, and the grain stack is mainly dependent on the migration speed of moisture. The larger the temperature difference is, the faster the moisture transfer speed is, otherwise, the slower the moisture transfer speed is, if the temperature difference in the grain pile is smaller, the moisture transfer time is longer than the season alternation time, and dew or mildew cannot be formed. Therefore, the grain storage will not have problems, and depends on the temperature difference and the strength of micro air flow.
In summary, in the actual grain storage process, under the effect of factors such as environment, a plurality of physical fields such as a pressure field, a temperature field, a humidity field, a micro air flow field and the like exist in the grain pile at the same time, and all physical factors are mutually influenced, so that mildew, condensation, insect damage and the like generated by the grain pile are not the influence between a single two fields, but the coupling effect of a plurality of physical fields, which cannot be considered by the existing experimental device. The experiment of multi-physical field coupling of the grain pile is realized, the existing experimental method of multi-field coupling of the grain pile for storing grains can be made up, and a more scientific basis can be provided for ecological research of the grains. In view of the above, the invention is extremely important to an experimental platform capable of realizing the coupling research of multiple physical fields (pressure field, temperature field, humidity field and micro-airflow field) in the grain pile.
Disclosure of Invention
The invention aims to provide a bulk grain pile multi-field coupling experimental device, which simulates environmental conditions in different areas and different positions in a granary by controlling pressure, temperature, humidity, ventilation conditions and the like, and establishes a basic mathematical model of multi-physical field coupling for researching multi-field coupling basic rules of grain pile pressure fields, temperature fields, humidity fields and micro-air flow fields.
In order to achieve the above purpose, the present invention may adopt the following technical scheme:
the multi-field coupling experimental device for the bulk grain stack comprises an upper opening model box body with a square structure for containing grains, wherein temperature and humidity sensors are arranged in the model box body, and observation windows are arranged on the front side wall and the rear side wall of the model box body;
the left side wall and the right side wall of the model box body are of cavity structures, circulating water pipes are respectively arranged in the left side wall and the right side wall of the model box body, and the circulating water pipes in the left side wall and the right side wall are respectively communicated with an external high-temperature control system and a low-temperature control system;
the automatic grain feeding device is characterized in that a servo flexible loading control system is arranged at the opening of the model box body and comprises a cover plate buckled at the opening of the model box body, a pressure air bag is horizontally arranged at the lower part of the cover plate, and a pressure sensor is arranged on the contact surface between the lower part of the pressure air bag and grains.
The high-temperature control system comprises a high-temperature water storage tank, a heating device is arranged in the high-temperature water storage tank, and a water inlet and a water outlet of a circulating water pipe in the left side wall of the model box body are communicated with the high-temperature water storage tank through a hot water pipeline with a circulating pump; the low-temperature control system comprises a low-temperature water storage tank, a cooling device is arranged in the low-temperature water storage tank, and a water inlet and a water outlet of a circulating water pipe in the right side wall of the model box body are communicated with the low-temperature water storage tank through a cold water pipeline with a circulating pump.
The outer surfaces of the left side wall and the right side wall are provided with heat insulation layers; the heating device is a wind-heated type totally-enclosed compressor unit; the cooling device is an air-cooled totally-enclosed compressor unit.
The ventilation channels are formed by sealing connection between ventilation holes correspondingly formed in the inner laminate plate and the outer laminate plate of the left side wall and the right side wall, and the plugging piece is screwed on the outer side of the ventilation channels.
The left side wall and the right side wall are hermetically sealed and provided with micro-airflow collecting covers, the outlets of the micro-airflow collecting covers are connected with transparent horizontal pipes, and liquid drops are placed in the transparent horizontal pipes.
An air outlet of the centrifugal fan controlled by the computer to work through the air pressure control system is connected with an air duct on the side wall of the model box body through a ventilation pipe.
The pressure air bag consists of a plurality of mutually independent bag cavities, the lower surface of the cover plate is of a compartment type structure matched with the bag cavities in size, and a rubber pad is arranged on the joint surface of the bag cavities and the cover plate.
The air pressure of the pressure air bag is regulated and controlled by a computer through an air pressure servo control system.
An industrial camera is arranged outside one observation window of the model box body, and an infrared thermal image device is arranged outside the other observation window.
The experimental device is placed in a constant temperature and humidity environment which is regulated by a constant temperature and humidity machine.
The experimental device has the advantages that the experimental device is simple in structure, convenient to operate and high in accuracy, and the model box filled with grains is used as a specific position in the granary, and the grain storage environments under the conditions of different areas, different seasons, different grain loading heights and different temperature and humidity combinations can be accurately simulated through the pressure control system arranged at the upper opening and the temperature control system arranged outside the side wall of the experimental device; the mechanical ventilation adjusting process in the actual grain storage process can be accurately simulated through the ventilation control system; through a visual window, researching the change of the internal porosity of the grain pile by using a digital image technology; the migration process of micro air flow in the grain pile can be researched through the infrared thermal digital image; the change of grain pile micro-air flow caused by temperature difference is researched by a water drop method; the measures are combined mutually, so that the research on the multi-field coupling rule of the pressure field, the temperature field, the humidity field and the micro air flow field in the grain pile is realized.
Drawings
Fig. 1 is a schematic structural view of the present invention.
Fig. 2 is a structural view of the left and right sidewalls in fig. 1.
Fig. 3 is a schematic view of a sidewall of the hollow cavity structure of fig. 1.
Detailed Description
The invention will be described in more detail with reference to the accompanying drawings.
As shown in figure 1, the bulk grain pile multi-field coupling experimental device comprises an upper opening model box body 1 with a square structure for containing grains, wherein the size of the model box body 1 is 1m multiplied by 1m, a pressure sensor and a temperature and humidity sensor are arranged in the model box body 1 (the sensor position is generally arranged at the central position of the model box body 1, a lead wire can be led out from an opening and connected into a data acquisition system), in order to facilitate the observation of the grain porosity and the dynamic change of micro-air flow in the model box body, observation windows 2 (transparent organic glass can be adopted for the front side wall and the rear side wall in actual manufacturing) are arranged on the front side wall and the rear side wall of the model box body 1, a CCD industrial camera 3 is arranged outside one observation window, and infrared thermal image equipment (not shown in the figure) is arranged outside the other observation window; the left and right side walls of the model box body 1 are of hollow structures (made of metal plates), circulating water pipes (shown in figure 2) are respectively arranged in the left and right side walls, and the circulating water pipes in the left and right side walls are respectively communicated with an external high-temperature control system and a low-temperature control system; a servo flexible loading control system is arranged at the opening of the model box body 1.
Specifically, in order to accurately simulate the temperature gradient in an actual granary, the high-temperature control system comprises a high-temperature circulating water pipe arranged in a left side wall 4.1, a water inlet of the high-temperature circulating water pipe is communicated with a high-temperature water storage tank 6.1 through a hot water pipeline with a high-temperature side circulating pump 5.1, a water outlet of the high-temperature circulating water pipe is communicated with a water inlet of the high-temperature water storage tank 6.1 through a water return pipeline, a heating device (a commercially available product) of a wind-heating type fully-closed compressor unit is arranged in the high-temperature water storage tank 6.1, the circulating water is heated to the temperature required by experiments (the highest temperature is not more than 98 ℃ and the lowest temperature is 30 ℃ and can basically cover the high-temperature environment of grain stored in the granary), and a water supplementing port can be further arranged on the high-temperature water storage tank 6.1 if necessary to supplement the circulating water (of course, the upper cover can be taken down to directly supplement water); the low-temperature control system comprises a low-temperature circulating water pipe arranged in a right side wall 4.2, wherein a water inlet of the low-temperature circulating water pipe is communicated with a low-temperature water storage tank 6.2 through a cold water pipeline with a low-temperature side circulating pump 5.2, a water outlet of the low-temperature circulating water pipe is communicated with a water inlet of the low-temperature water storage tank 6.2 through a water return pipeline, an air-cooled fully-closed compressor unit (a commercially available product) is arranged in the low-temperature water storage tank 6.2, water is fed into (or directly cooled by a miniature cold water machine) after being cooled, and the temperature of cold water can be adjusted between 0 ℃ and 30 ℃ according to actual experiment requirements; in order to improve the heat preservation effect of the left side wall and the right side wall, heat preservation layers can be arranged on the outer surfaces of the left side wall and the right side wall.
In order to accurately simulate the mechanical ventilation adjusting effect in the actual grain storage process, the invention also designs a ventilation control system: the ventilation channels are formed by sealing connection between ventilation holes correspondingly formed in the inner laminate and the outer laminate of the left side wall and the right side wall, and sealing pieces (sealing bolts with sealing rings) are screwed on the outer sides of the ventilation channels; during experiments, the computer 9 controls the air outlet of the working centrifugal fan 12 through the air pressure control system 11 (air pressure controller) to be connected with the air channel on the side wall of the model box body 1 through the ventilation pipe, and a certain air pressure ventilation amount is provided for the grain pile in the model box body 1.
The funnel-shaped micro-airflow collecting covers are arranged on the outer sides of the left side wall and the right side wall in a sealing way, as shown in fig. 3, taking the right side wall 4.2 as an example (the left side wall is the same): the funnel-shaped micro-air flow collecting cover 4.3 is connected to the outer side of the right side wall 4.2, the transparent horizontal guide pipe 4.4 is connected to the outlet of the micro-air flow collecting cover 4.3, liquid drops 4.5 (the liquid drops 4.5 have the characteristics of small volume weight, small viscous resistance and non-volatilization) are placed in the transparent horizontal guide pipe 4.4, at the moment, in a non-ventilation state, plugging pieces are unscrewed, micro-air flows are formed in the model box 1 at different temperatures of the left side wall and the right side wall, the micro-air flows are collected by the micro-air flow collecting cover 4.3 and enter the transparent guide pipe 4.4 to push the liquid drops 4.5 to move, and then the total micro-air flow of the grain pile under different temperature difference effects can be studied.
The servo loading control system comprises a cover plate 7 (precisely machined by high-strength steel) buckled at the opening of a model box body 1, wherein a pressure air bag 8 is horizontally arranged at the lower part of the cover plate 7, and a pressure sensor is arranged on the contact surface between the lower part of the pressure air bag 8 and grains. In order to ensure the pressure balance of the grain pile in the model box body 1, the pressure air bag 8 can be formed by a plurality of mutually independent (four are shown in the figure) air bags in actual manufacturing, the lower surface of the cover plate 7 is of a compartment type structure matched with the number and the size of the air bags, and a rubber pad is arranged on the joint surface of the air bags and the cover plate 7, so that the abrasion of the air bags can be effectively avoided. During experiments, the internal air pressure of each cavity of the pressure air bag 8 can be regulated and controlled by the computer 9 through the air pressure servo control system 10. A pressure sensor is arranged on the contact surface between the lower part of the pressure air bag 8 and the grain pile (a layer of geotechnical cloth can be paved on the upper surface of the grain, and the pressure sensor is arranged on the geotechnical cloth); when the gas enters the pressure air bag 8, pressure is generated on the grain pile (the pressure value of the grain pile can be acquired through the pressure sensor), and the cover plate 7 plays a role in restraining the pressure air bag 8 and providing reaction force for the pressure air bag at the same time; the pressure exerted by the flexible loading pressure bladder 8 is more uniform relative to a rigid platen, and the loading load is continuously stabilized using computer feedback control. In order to ensure that the heat of the model box body 1 is transferred in one-dimensional direction, a heat insulation cushion layer can be paved on the bottom surface of the model box body 1.
In order to simulate grain storage environments in different areas and in different seasons, the experimental device provided by the invention is placed in a constant temperature and humidity environment (such as a constant temperature and humidity chamber 13), and the temperature and humidity of the constant temperature and humidity environment can be regulated by a constant temperature and humidity machine 14.
The application method of the one-dimensional multi-field coupling experimental device for bulk grain stacks provided by the invention comprises the following steps:
1. preparation: the temperature environment of the laboratory is regulated, a sufficient amount of wheat/corn/rice with different water contents is prepared and placed in a constant temperature and humidity chamber 13, so that the temperature of grains is consistent with the ambient temperature, and the humidity reaches an equilibrium state; measuring the rigidity of wheat/corn/rice, selecting rubber pads close to the rigidity of the wheat/corn/rice, and pasting the rubber pads on the metal plates at the left side and the right side in the model box body 1 to ensure that the boundary condition is close to the rigidity of a grain pile; a rubber pad is arranged on the lower side of the pressure air bag 8 for pasting a pressure sensor and ensuring the uniformity of pressurization.
2. Calibrating a sensor: calibrating the pressure of wheat/corn/rice through a measurement experiment of the interface pressure of grain particles and a structure, and selecting a pressure sensor with a proper size; through the preliminary experiment, the temperature sensor and the humidity sensor are calibrated, so that the requirements of experimental measurement can be met.
3. Arranging a photogrammetry instrument: the CCD industrial camera 3 is fixed at the position 1.0m in front of the front observation window of the model box body 1, and the front vertical surface of the organic glass observation window 2 is adjusted to be completely arranged in the central range of the visual field of the camera; the camera of the infrared thermal imaging equipment is fixed at the position of 1.0m outside the rear observation window of the model box body 1, and the imaging visual angle is adjusted, so that the front vertical surface of the organic glass window is completely arranged in the central range of the visual field.
4. And (3) adjusting a temperature control system: according to experimental requirements, a wind-heat type totally-enclosed compressor unit is adopted to heat water in a high-temperature water storage tank 6.1, the water is sent to a high-temperature circulating water tank 4.1 through a high-temperature side circulating pump 5.1, after heat exchange is generated between hot water in the high-temperature circulating water tank 4.1 and the side wall of a model box body 1, the hot water flows back to the high-temperature water storage tank 6.1, and after a period of hot water circulation, the temperature of a high-temperature side wall plate of the model box body 1 is constant, and a constant temperature field is formed; meanwhile, cold water generated after refrigeration by the air-cooled totally-enclosed compressor unit is sent into the low-temperature water storage tank 6.2, the cold water is sent into the low-temperature circulating water tank 4.2 by the low-temperature side circulating pump 5.2, and after heat exchange is generated between the cold water and the side wall of the model box body 1, the cold water flows back into the low-temperature water storage tank 6.2, and after a period of cold water circulation, the temperature of the low-temperature side wall plate of the model box body 1 is constant, so that a constant temperature field is formed.
Unscrewing the plugging pieces in the ventilating ducts on the left and right side walls of the model box body 1, and recording the positions of the liquid drops 4.5 in the transparent horizontal guide pipe 4.4 when the temperatures of the left and right side wall surfaces are constant; the micro air flow in the model box 1 can be calculated and measured according to the moving distance of the liquid drop 4.5.
5. Loading grains and embedding sensors: taking wheat as an example, loading wheat with a certain moisture content into a model box body 1 according to the density in an actual granary in a layering manner, respectively arranging a pressure sensor (layering and dividing plane arrangement), a temperature sensor (layering and dividing plane arrangement) and a humidity sensor (layering and dividing plane arrangement) at corresponding positions in a grain pile according to experimental requirements when loading grains, loading grains until the height is 950 mm, enabling the surface level of the grains, and recording the pressure value, the temperature value and the humidity value in an initial state.
6. Placing a pressure air bag 8 and a cover plate 7: the pressure sensor is stuck to geotechnical cloth under the air bag according to experimental requirements, and a cover plate 8 is placed to provide constraint counter force for the pressure air bag 7. All sensor leads in the grain pile are led out from one side of the pressure air bag 8, and are led out through lead holes reserved on the cover plate 7 to be connected with an external data acquisition system.
7. Checking and adjusting: checking whether a sensor (comprising a pressure sensor, a temperature sensor and a humidity sensor) is connected, checking connection of an air pressure servo control system, a temperature control system and the like, checking whether a ventilation control system is connected, checking and adjusting visual angles of infrared thermal image equipment and a CCD industrial camera, and fixing; experimenters were temporarily away to reduce interference.
8. Applying pressure: the air pressure servo control system 10 is regulated, the pressure value is regulated according to experimental requirements, and the change of the pressure value at different positions inside the grain pile caused by different grain pile heights in actual grain storage is simulated.
9. Ventilation experiment: the micro-airflow collecting cover is removed, the centrifugal ventilator 12 is connected with a ventilation pipe, the ventilation pipe is connected with a ventilation channel on the side wall of the model box body 1, rubber mats are required to be added at all the connecting positions, and the air tightness during ventilation is ensured; then, according to the experimental requirements, a certain wind pressure and ventilation quantity are set through the computer 9, and the centrifugal ventilator 12 is controlled to work through the wind pressure control system 11 to ventilate the model box 1.
10. Data recording and reading: the infrared thermal image equipment and the CCD industrial camera 3 are used for automatically recording pictures of the grain pile, and the data acquisition system is used for automatically recording pressure values, temperature values and humidity values in the grain pile in the experimental process.
11. And (3) data processing: according to Matlab software, the pictures of the change of the grain pile porosity under different pressures can be processed, grain particles and pores are distinguished, the porosity of the grain pile under different pressures, and the grain orientation arrangement rule and the mechanical ventilation effect are achieved. According to the infrared thermal digital image, the migration speed of airflow in the grain pile can be obtained through processing; according to the moving distance of the water drops in the guide pipe, the total micro air flow in the grain medium can be obtained under the action of different temperature differences; the data acquisition system can acquire the pressure value, the temperature value and the humidity value in the grain pile in the experimental process. According to the obtained data, the multi-physical field coupling transfer rule of the grain pile pressure field, the temperature field, the humidity field and the micro air flow field can be fit and researched.
Claims (6)
1. A bulk grain pile multi-field coupling experimental device is characterized in that: the grain-containing box comprises an upper opening model box body with a square structure for containing grains, wherein a temperature sensor and a humidity sensor are arranged in the model box body, and observation windows are arranged on the front side wall and the rear side wall of the model box body;
the left side wall and the right side wall of the model box body are of cavity structures, circulating water pipes are respectively arranged in the left side wall and the right side wall of the model box body, and the circulating water pipes in the left side wall and the right side wall are respectively communicated with an external high-temperature control system and a low-temperature control system;
a servo flexible loading control system is arranged at the opening of the model box body and comprises a cover plate buckled at the opening of the model box body, a pressure air bag is horizontally arranged at the lower part of the cover plate, and a pressure sensor is arranged on the contact surface between the lower part of the pressure air bag and grains;
the high-temperature control system comprises a high-temperature water storage tank, a heating device is arranged in the high-temperature water storage tank, and a water inlet and a water outlet of a circulating water pipe in the left side wall of the model box body are communicated with the high-temperature water storage tank through a hot water pipeline with a circulating pump; the low-temperature control system comprises a low-temperature water storage tank, a cooling device is arranged in the low-temperature water storage tank, and a water inlet and a water outlet of a circulating water pipe in the right side wall of the model box body are communicated with the low-temperature water storage tank through a cold water pipeline with a circulating pump;
the outer surfaces of the left side wall and the right side wall are provided with heat insulation layers; the heating device is a wind-heated type totally-enclosed compressor unit; the cooling device is an air-cooled totally-enclosed compressor unit;
the inner laminate plate and the outer laminate plate of the left side wall and the right side wall are correspondingly provided with ventilation holes which are connected in a sealing way to form a ventilation channel, and a plugging piece is screwed on the outer side of the ventilation channel;
the left side wall and the right side wall are hermetically sealed and provided with micro-airflow collecting covers, the outlets of the micro-airflow collecting covers are connected with transparent horizontal pipes, and liquid drops are placed in the transparent horizontal pipes.
2. The bulk grain stack multi-field coupling experimental device of claim 1, wherein: an air outlet of the centrifugal fan controlled by the computer to work through the air pressure control system is connected with an air duct on the side wall of the model box body through a ventilation pipe.
3. The bulk grain stack multi-field coupling experimental device of claim 1, wherein: the pressure air bag consists of a plurality of mutually independent bag cavities, the lower surface of the cover plate is of a compartment type structure matched with the bag cavities in size, and a rubber pad is arranged on the joint surface of the bag cavities and the cover plate.
4. The bulk grain stack multi-field coupling experimental device of claim 1, wherein: the air pressure of the pressure air bag is regulated and controlled by a computer through an air pressure servo control system.
5. The bulk grain stack multi-field coupling experimental device of claim 1, wherein: an industrial camera is arranged outside one observation window of the model box body, and an infrared thermal image device is arranged outside the other observation window.
6. The bulk grain stack multi-field coupling experimental device of claim 1, wherein: the experimental device is placed in a constant temperature and humidity environment which is regulated by a constant temperature and humidity machine.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810141040.6A CN108227796B (en) | 2018-02-11 | 2018-02-11 | Multi-field coupling experimental device for bulk grain stack |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810141040.6A CN108227796B (en) | 2018-02-11 | 2018-02-11 | Multi-field coupling experimental device for bulk grain stack |
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| CN109884948A (en) * | 2019-03-19 | 2019-06-14 | 辽宁省粮食科学研究所 | A kind of Multifunctional grain situation monitoring experiment system and its control method |
| CN110068504B (en) * | 2019-06-09 | 2024-01-30 | 河南工业大学 | Device and method for testing influence of internal temperature and humidity of grain on compression characteristics of grain |
| CN112304856A (en) * | 2020-11-06 | 2021-02-02 | 国家粮食和物资储备局科学研究院 | Test device for tracking and detecting multi-factor coupling effect of grain pile and environment |
| CN113390463B (en) * | 2021-06-15 | 2023-01-24 | 河南工业大学 | Grain storage simulation multi-field coupling test platform |
| CN114216928A (en) * | 2021-11-19 | 2022-03-22 | 河南工业大学 | Simulation granary device for measuring airflow resistance and heat transfer characteristic of grain pile and measuring method |
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