Propane storage tank heating characteristic analysis method and device

Abstract

The invention relates to the technical field of liquid air energy storage, and provides a propane storage tank temperature rise characteristic analysis method and device, and the method comprises the steps: determining a plurality of temperature measurement points of a two-dimensional propane storage tank, the plurality of temperature measuring points comprise a first temperature measuring point arranged at the liquid phase of the two-dimensional propane storage tank, a second temperature measuring point arranged at the junction of the gas phase and the liquid phase, and a third temperature measuring point arranged at the gas phase; acquiring a plurality of groups of temperature data in a preset time period, wherein the temperature data comprises a plurality of temperature values corresponding to the plurality of temperature measurement points; and obtaining the temperature distribution condition of the propane storage tank based on the multiple groups of temperature data. According to the propane storage tank temperature rise characteristic analysis method provided by the invention, a plurality of temperature measurement points are arranged on a two-dimensional propane storage tank to obtain temperature data of a liquid phase, a gas-liquid two-intersection interface and a gas phase, and the temperature distribution condition of the propane storage tank is obtained based on the change of the temperature data along with time in a heat leakage process, so that the temperature rise characteristic of the propane storage tank is obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid air energy storage, and in particular to a method and device for analyzing the temperature rise characteristics of a propane storage tank. Background Art

[0002] Liquid air energy storage research is to solve the intermittent and unstable problems of renewable energy and provide an effective energy storage solution. As a lightweight, high-energy-density liquefied medium, the safe and efficient storage of propane in the tank directly affects the efficiency and safety of the system.

[0003] Propane tanks play an important role in liquid air energy storage systems, and the stability of their internal temperature is crucial to the efficiency and safety of the entire system. Therefore, the study of the heating characteristics of propane tanks is an important issue that needs to be solved in the industry. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a method and device for analyzing the temperature rise characteristics of a propane storage tank, which can effectively analyze the temperature rise characteristics of a propane storage tank.

[0005] The present invention provides a method for analyzing the temperature rise characteristics of a propane storage tank, comprising: Determine a plurality of temperature measurement points of the two-dimensional propane storage tank, wherein the plurality of temperature measurement points include a first temperature measurement point disposed at the liquid phase of the two-dimensional propane storage tank, a second temperature measurement point at the interface between the gas and liquid phases, and a third temperature measurement point at the gas phase; Acquire multiple sets of temperature data within a preset time period, wherein the temperature data includes multiple temperature values ​​corresponding to multiple temperature measurement points; Based on the multiple groups of temperature data, the temperature distribution of the propane storage tank is obtained.

[0006] According to a method for analyzing temperature rise characteristics of a propane storage tank provided by the present invention, the multiple sets of temperature data include multiple sets of first temperature data, and the step of obtaining multiple sets of temperature data within a preset time period includes: When the two-dimensional propane storage tank has no external cold source, obtaining multiple sets of first temperature data within a preset time period; After obtaining the temperature distribution of the propane storage tank based on the multiple sets of temperature data, the method further includes: Based on the temperature distribution of the propane storage tank, it is determined that the heating rate of nitrogen is greater than the heating rate of liquid propane.

[0007] According to a method for analyzing temperature rise characteristics of a propane storage tank provided by the present invention, the multiple sets of temperature data include multiple sets of second temperature data, and the multiple sets of temperature data within a preset time period are obtained, including: Introducing multiple cooling forms to the two-dimensional propane tank; For each cooling form, obtaining multiple sets of second temperature data within a preset time period; After obtaining the temperature distribution of the propane storage tank based on the multiple sets of temperature data, the method further includes: The plurality of sets of second temperature data of the plurality of cooling forms are compared, and a cooling mode with the best temperature uniformity and / or a cooling mode with the best temperature reduction effect is determined as a target cooling mode.

[0008] According to a method for analyzing the temperature rise characteristics of a propane storage tank provided by the present invention, the multiple cooling forms include a method of introducing cold energy at the nitrogen in a two-dimensional propane storage tank, a method of introducing cold energy at the upper part of the liquid propane in the two-dimensional propane storage tank, and a method of introducing cold energy at the lower part of the liquid propane in the two-dimensional propane storage tank. The target cooling method is a method of introducing cold energy at the upper part of the liquid propane in the two-dimensional propane storage tank.

[0009] According to a method for analyzing temperature rise characteristics of a propane storage tank provided by the present invention, before acquiring multiple groups of temperature data within a preset time period, the method further includes: Determining a heat transfer relationship of the two-dimensional propane storage tank based on the heat transfer characteristics of the two-dimensional propane storage tank; Based on the heat transfer relationship, determining the amount of heat leakage transferred from the external environment to the two-dimensional propane storage tank; Based on the heat leakage, determining boundary conditions; The step of obtaining multiple sets of temperature data within a preset time period includes: A plurality of groups of temperature data within a preset time period are acquired under the boundary conditions.

[0010] According to a method for analyzing the temperature rise characteristics of a propane storage tank provided by the present invention, the heat transfer relationship of the two-dimensional propane storage tank is determined, including: Determine the heat transfer relationship based on formula (1); (1) in, represents the amount of heat transferred; A represents the heat transfer area; k represents the heat transfer coefficient, , R1 represents the thermal resistance of thermal conductivity, R2 represents the thermal resistance of convection, and R3 represents the thermal resistance of radiation Indicates the temperature of propane in the propane tank. Indicates the temperature of the nitrogen in the propane tank.

[0011] According to a method for analyzing temperature rise characteristics of a propane storage tank provided by the present invention, before acquiring multiple groups of temperature data within a preset time period, the method further includes: The thermal relationship between the thermophysical parameters of liquid propane and nitrogen and the temperature is obtained, wherein the thermophysical parameters include density, thermal conductivity, and specific heat capacity.

[0012] According to a method for analyzing the temperature rise characteristics of a propane storage tank provided by the present invention, the structural parameters of the two-dimensional propane storage tank remain constant, and the structural parameters include at least one of the thickness of the insulation layer, the heat leakage in all directions of the tank body, the outer wall temperature of the tank body, the tank body pressure, and the tank body material.

[0013] The present invention also provides a propane tank temperature rise characteristic analysis device, comprising the following modules: A determination module, used to determine a plurality of temperature measurement points of the two-dimensional propane storage tank, wherein the plurality of temperature measurement points include a first temperature measurement point set at the liquid phase of the two-dimensional propane storage tank, a second temperature measurement point at the junction of the gas-liquid phase, and a third temperature measurement point of the gas phase; An acquisition module, used to acquire multiple sets of temperature data within a preset time period, wherein the temperature data includes multiple temperature values ​​corresponding to multiple temperature measurement points; The obtaining module is used to obtain the temperature distribution of the propane storage tank based on the multiple groups of temperature data.

[0014] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the method for analyzing the temperature rise characteristics of a propane storage tank as described above is implemented.

[0015] The method for analyzing the temperature rise characteristics of a propane storage tank provided by the present invention sets multiple temperature measuring points on a two-dimensional propane storage tank to obtain temperature data of the liquid phase, the gas-liquid interface and the gas phase, and based on the change of the temperature data over time during the heat leakage process, obtains the temperature distribution of the propane storage tank to obtain the temperature rise characteristics of the propane storage tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is one of the flow diagrams of the method for analyzing the temperature rise characteristics of a propane storage tank provided by the present invention.

[0018] Figure 2 It is a structural schematic diagram of a two-dimensional propane storage tank provided by the present invention.

[0019] Figure 3 This is the second flow chart of the propane storage tank temperature rise characteristic analysis method provided by the present invention.

[0020] Figure 4 It is a schematic diagram of the change of the heat leakage with the internal fluid temperature provided by the present invention.

[0021] Figure 5 It is a schematic diagram of three cooling forms of a two-dimensional propane storage tank provided by the present invention; wherein, Figure (a) represents the cooling gas form, Figure (b) represents the cooling liquid upper form, and Figure (c) represents the cooling liquid lower form.

[0022] Figure 6 This is the third flow chart of the method for analyzing the temperature rise characteristics of a propane storage tank provided by the present invention.

[0023] Figure 7 This is the fourth flow chart of the propane storage tank temperature rise characteristic analysis method provided by the present invention.

[0024] Figure 8 It is a structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0025] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0026] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0027] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0028] In the embodiments of the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0029] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0030] Combine the following Figure 1-Figure 7 The method for analyzing the temperature rise characteristics of a propane storage tank according to the present invention is described.

[0031] The embodiment of the first aspect of the present invention provides a method for analyzing the temperature rise characteristics of a propane storage tank, such as Figure 1 As shown, the analysis method includes the following steps: Step 100, determining a plurality of temperature measuring points of the two-dimensional propane storage tank, wherein the plurality of temperature measuring points include a first temperature measuring point disposed at the liquid phase of the two-dimensional propane storage tank, a second temperature measuring point at the interface between the gas and liquid phases, and a third temperature measuring point at the gas phase.

[0032] It is understandable that if Figure 2 As shown, a two-dimensional propane storage tank is used as the research object, which has uniform stress distribution and good mechanical strength. The lower part of the two-dimensional propane storage tank is liquid propane, and the upper part is nitrogen. Three temperature measuring points are set in the two-dimensional propane storage tank, namely the first temperature measuring point in the liquid propane, the second temperature measuring point at the interface of liquid propane and nitrogen, and the third temperature measuring point in the nitrogen, which are used to monitor the temperature changes of the liquid phase, the gas-liquid interface and the gas phase over time during the heat leakage process.

[0033] Step 200: Acquire multiple sets of temperature data within a preset time period, where the temperature data includes multiple temperature values ​​corresponding to multiple temperature measurement points.

[0034] It can be understood that at the beginning of the experiment, the temperatures of the first temperature measuring point, the second temperature measuring point and the third temperature measuring point are obtained. At this time, the temperatures of the first temperature measuring point, the second temperature measuring point and the third temperature measuring point are equal, which are used as the initial temperature inside the storage tank; thereafter, at a certain interval, the temperature of the first temperature measuring point, the temperature of the second temperature measuring point and the temperature of the third temperature measuring point are obtained, and the temperature of the first temperature measuring point, the temperature of the second temperature measuring point and the temperature of the third temperature measuring point are used as a set of temperature data. By obtaining a set of temperature data at a certain interval, multiple sets of temperature data are obtained within a preset time period.

[0035] Step 300: Based on multiple sets of temperature data, obtain the temperature distribution of the propane storage tank.

[0036] It can be understood that by comparing and analyzing the temperature changes of multiple groups of temperature data, the temperature distribution of the propane storage tank is obtained, so as to obtain the temperature rise characteristics of the propane storage tank.

[0037] The method for analyzing the temperature rise characteristics of a propane storage tank provided in an embodiment of the present invention sets multiple temperature measuring points on a two-dimensional propane storage tank to obtain temperature data of the liquid phase, the gas-liquid interface, and the gas phase, and based on the change of temperature data over time during the heat leakage process, the temperature distribution of the propane storage tank is obtained to obtain the temperature rise characteristics of the propane storage tank, thereby providing a theoretical basis and technical support for the safe and efficient storage of propane and the optimization of liquid air energy storage systems.

[0038] In one embodiment of the present invention, Figure 3 As shown, before executing step 200, the method further includes the following steps: Step 400: Determine a heat transfer equation of the two-dimensional propane storage tank based on the heat transfer characteristics of the two-dimensional propane storage tank.

[0039] Step 500: Determine the amount of heat leakage transferred from the external environment to the two-dimensional propane storage tank based on the heat transfer equation.

[0040] Specifically, as a storage container for liquid propane, the internal temperature of a propane tank can reach -178°C, while the temperature outside the propane tank is approximately -20°C to 35°C, with a difference of more than 200°C. Heat will continuously transfer from the outside of the propane tank to the inside; heat transfer includes heat conduction, convection, and thermal radiation. By analyzing these three heat transfer methods, the heat leakage of the propane tank can be calculated.

[0041] The first one is the heat conduction of propane tanks.

[0042] The phenomenon of heat conduction exists in gases, solids, and liquids. Energy is transferred and exchanged from high to low through the medium. The form of heat conduction in propane storage tanks is mainly achieved through the cold insulation material of the tank body to achieve heat conduction exchange between the inner tank temperature and the external temperature; among them, the tank body is a double-layer structure, including an inner tank, an outer tank and an insulation layer arranged between the inner tank and the outer tank, and the insulation layer is made of cold insulation material.

[0043] Since the thickness of the tank (i.e., propane tank) is much smaller than the circumference and height, the temperature change frequency in the thickness direction is much greater than the temperature change rate in the circumference and width directions, so the heat conduction in the circumference and height directions is ignored. The heat flux of the propane tank heat transfer is determined according to Fourier's heat conduction differential equation, where Fourier's heat conduction differential equation is based on the heat conduction law and the law of conservation of energy.

[0044] The second type is convection of propane tanks.

[0045] When a fluid contacts a solid, heat transfer occurs between the fluid and the solid surface due to the movement of the external fluid particles, which is called convective heat transfer. During the precooling process of the propane storage tank, the precooling medium propane can be sprayed through the spray system to cool down. The propane gasification phenomenon is obvious during the initial cooling. At this time, accompanied by the phase change of propane, stratification and tumbling will occur in the propane storage tank, so convective heat transfer will be accompanied by heat conduction, and the convective heat transfer law is unstable. Convective heat transfer in propane storage tanks exists in gas (nitrogen) and liquid (liquid propane), mainly including convective heat transfer between the gas in the tank ceiling cavity, the gas in the tank wall insulation layer, the outer tank wall and the atmosphere, and the propane fluid in the tank and the tank wall.

[0046] The convective heat transfer phenomenon in propane storage tanks follows Newton's law of cooling. The heat flow rate of the fluid flowing through the solid wall is proportional to the temperature difference between the wall and the fluid, and the direction of the heat flow is from high temperature to low temperature.

[0047] Specifically, the heat transfer amount of convective heat transfer is determined by formula (2); (2) in, Indicates the amount of heat transferred, in watts (W); q Indicates heat flux density in watts per square meter (W / m²); h Indicates the heat transfer coefficient, the unit is W / m²·K; Indicates the contact area, i.e. the heat exchange area, in square meters (m²); Represents the temperature difference between the tank wall and the fluid, in Kelvin (K).

[0048] The third type: thermal radiation from propane tanks Two objects with different temperatures can exchange heat through electromagnetic radiation without contact, and thermal radiation does not require a medium. In order to simplify the calculation of radiation heat transfer of propane tanks, the following settings are made: (I) a medium or vacuum that does not participate in the radiation between the surfaces undergoing radiation heat transfer; (II) The surfaces of objects involved in residual radiation heat transfer are all diffuse gray surfaces; (III) The temperature, radiation characteristics and input radiation distribution of each surface are uniform; (IV) The radiation is approximately assumed to occur in a closed cavity formed by parallel walls.

[0049] Step 600: Determine boundary conditions based on the heat leakage.

[0050] For example, a cylindrical two-dimensional propane tank is used as the research object, such as Figure 2 As shown, the cylinder diameter R is 26m, the height H1 is 24m, the height H2 of the liquid propane is 15m, the upper part is nitrogen, and the lower part is liquid propane. Figure 2 1, 2, and 3 represent the first temperature measuring point, the second temperature measuring point, and the third temperature measuring point, respectively. The first temperature measuring point is located in the middle of the nitrogen, and the third temperature measuring point is located in the middle of the liquid propane.

[0051] There are three heat transfer modes in propane storage tanks: conduction, convection, and thermal radiation. Heat is transferred in propane storage tanks in these three modes, and the three heat transfer modes of conduction, convection, and thermal radiation generally exist at the same time. The heat transfer process is relatively complicated. For the convenience of calculation, the structural parameters of the two-dimensional propane storage tank are set to remain constant. The structural parameters include at least one of the thickness of the insulation layer, the amount of heat leakage in all directions of the tank body, the outer wall temperature of the tank body, the tank body pressure, and the tank body material.

[0052] For example, the structural parameters of a two-dimensional propane tank are set to meet the following conditions: ①The thickness of the thermal insulation layer of the propane tank is uniform, ignoring irregularities, that is, the thickness of the thermal insulation layer remains constant; ② The materials of the propane tank are homogeneous (isotropic), and the effect of temperature on the thermal conductivity of the material is ignored, that is, the material of the tank remains constant; ③ The external heat source of the propane storage tank is evenly distributed, the environmental conditions are constant, and the outer surface temperature of the outer tank is consistent with the ambient temperature; ④ The heat leakage of the entire propane storage tank in all directions is uniform and constant, that is, the heat leakage in all directions of the tank body remains constant; ⑤The pressure distribution of the entire propane storage tank is uniform and constant, that is, the tank pressure remains constant.

[0053] Based on the above set conditions, in step 600, the heat transfer relationship of the two-dimensional propane storage tank is determined, including: Determine the heat transfer relationship based on formula (1); (1) in, represents the amount of heat transferred; A represents the heat transfer area; k represents the heat transfer coefficient, , R1 represents the thermal resistance of thermal conduction, R2 represents the thermal resistance of convection, and R3 represents the thermal resistance of radiation; Indicates the temperature of propane in the propane tank. Indicates the temperature of the nitrogen in the propane tank.

[0054] R1 is calculated by the following formula (3); (3) R2 is calculated by the following formula (4); (4) R3 is calculated by the following formula (5); (5) In the formula, Indicates the thermal conductivity of the inner tank, in W / (m·K); represents the thermal conductivity of the outer tank, Indicates the thickness of the inner tank in meters (m). Indicates the thickness of the outer tank; represents the emissivity, Indicates the temperature of propane in the propane tank. Indicates the temperature of the nitrogen in the propane tank.

[0055] In this embodiment, the propane storage tank is a closed container filled with liquid propane and nitrogen. The heat is transferred from the outside of the storage tank to the inside of the propane storage tank, and the temperature inside the container rises. As the temperature inside the container rises, the liquid propane will partially vaporize, resulting in an increase in the pressure inside the container. Initially, the temperature of the liquid propane in the container is assumed to be 95K, and the corresponding saturated vapor pressure is extremely low, only 5.43×10 −6 kPa. In order to maintain the pressure balance inside and outside the container, nitrogen is injected above the propane to ensure that the pressure inside the container is equal to the external atmospheric pressure. When the temperature of liquid propane rises by 5K to 100K, the saturated vapor pressure of propane increases slightly, but it is still very low, only 2.53×10 −5 kPa. Such a pressure change has very little effect on the total pressure in the container, so the amount of propane that becomes gaseous is almost negligible.

[0056] Based on the above analysis, the propane phase change process has a very small effect on the total pressure in the container. This embodiment does not consider the phase change process of propane. The interior of the container is always composed of liquid propane and nitrogen, with liquid propane at the bottom of the container and nitrogen at the top. The focus is on the internal heat transfer of liquid propane and nitrogen and the heat transfer process between the two. Therefore, this embodiment sets three temperature measurement points in the two-dimensional propane storage tank, corresponding to liquid propane, between liquid propane and nitrogen, and nitrogen, respectively, so as to realize the heat transfer process of liquid propane internal heat transfer, heat transfer between liquid propane and nitrogen, and heat transfer of nitrogen itself, so as to monitor the temperature change over time during the heat transfer process.

[0057] According to the heat transfer relationship, the amount of heat leakage transferred from the external environment to the two-dimensional propane tank is calculated. For example, the initial temperature of the fluid in the propane tank is obtained, and based on the heat transfer relationship, the total amount of heat leakage from the external environment to the tank is calculated. According to the geometric dimensions of the propane tank and the heat transfer process, the total amount of heat leakage is divided by the surface area of ​​the tank to obtain the heat flow of the outer wall of the tank. In the process of increasing the temperature in the tank, the temperature difference between the fluid and the external environment gradually decreases, so the amount of heat leakage will also gradually decrease. Considering the extreme case when the temperature in the tank rises to the external environment, the temperature difference with the external environment is 0, and the amount of heat leakage at this time will also be reduced to 0, so based on multiple amounts of heat leakage and the law of change of heat leakage with the temperature of the internal fluid, the boundary conditions are determined.

[0058] For example, step 200, obtaining multiple sets of temperature data within a preset time period, specifically includes the following contents: Acquire multiple sets of temperature data within a preset time period under boundary conditions.

[0059] Furthermore, before executing step 200, the method further includes: The thermal relationship between the thermophysical parameters of liquid propane and nitrogen and the temperature is obtained. The thermophysical parameters include density, thermal conductivity, and specific heat capacity.

[0060] For example, after determining the heat transfer relationship of a two-dimensional propane storage tank, the changes in the thermophysical parameters of liquid propane and nitrogen with temperature are analyzed to obtain the corresponding thermal relationship.

[0061] In a propane tank, two fluids, liquid propane and nitrogen, coexist. Since these two fluids are not only different in physical state, but also their respective thermophysical properties, such as density, thermal conductivity, and specific heat capacity, play a vital role in the formation of temperature distribution; their specific heat capacity and thermal conductivity determine the speed and efficiency of energy transfer in the tank. Over time, their density affects the size of convective heat transfer inside the fluid.

[0062] Taking gravity into account, the change of fluid density with temperature will affect the convection of liquid propane and nitrogen in the propane tank during the external heat leakage process. Liquid propane has a high density and is located in the lower part of the tank, while nitrogen has a low density and is located in the upper part of the tank. During the heating process, both remain in two phases, and there is heat transfer but no mass transfer at the phase interface, which means that the material exchange between liquid propane and nitrogen is mainly achieved through heat conduction, rather than mass transfer. It can be seen that the density of liquid propane and nitrogen decreases with the increase of temperature. Therefore, the fluid close to the wall of the tank is affected by external heating and is heated first. Due to the decrease in density, these fluids will move upward, causing convection inside the fluid; the convection phenomenon accelerates the heat transfer inside the fluid, making the temperature distribution inside the fluid tend to be uniform.

[0063] The thermal conductivity of propane is greater than that of nitrogen. As the temperature increases, the thermal conductivity of propane decreases, while the thermal conductivity of nitrogen increases, and both are approximately linearly related to temperature. This is related to the molecular structure and vibration of the substance. Propane molecules are more likely to vibrate at high temperatures, resulting in a decrease in their thermal conductivity, while the vibration of nitrogen molecules enhances their thermal conductivity. The difference in thermal conductivity between the two will decrease as the temperature increases. The high thermal conductivity of propane means that at the same temperature, propane is more likely to conduct heat and can more effectively conduct heat to other areas when absorbing heat.

[0064] The specific heat capacity of propane is much greater than that of nitrogen, about twice that of nitrogen. This means that at high temperatures, the internal energy of propane molecules and atoms increases faster and more heat is needed to raise their temperature. As the temperature rises, the specific heat capacity of propane increases dramatically, increasing by about 40% from 95K to 300K. The specific heat capacity of nitrogen decreases slightly as the temperature rises. Due to the difference in the specific heat capacity of propane and nitrogen, they behave differently when the temperature rises. Nitrogen, which has a smaller specific heat capacity, will heat up faster because it requires less heat to raise its temperature. In contrast, propane, which has a larger specific heat capacity, will heat up more slowly because it can store more heat. This difference becomes more obvious as the temperature rises. Therefore, in a propane tank, the temperature of the upper nitrogen will be higher than that of the lower liquid propane; due to the temperature difference between the two, heat transfer will occur.

[0065] It should be noted that this embodiment fully considers the changes in the thermophysical properties of propane and nitrogen fluids with temperature, thereby improving the accuracy of the analysis results of the temperature rise characteristics of the propane storage tank, and can provide powerful guidance for the design and operation of the storage tank, thereby optimizing the efficiency and safety of the liquid air energy storage system.

[0066] In this embodiment, according to the heat transfer relationship, when the initial temperature of the fluid in the propane tank is 95K, the total heat leakage from the external environment to the tank is calculated to be 52kW based on the heat transfer relationship. According to the geometric dimensions of the propane tank combined with the simplified heat transfer process, the total heat leakage is divided by the surface area of ​​the tank to obtain a heat flux of 9W / m 2 .

[0067] It should be noted that since the calculation cycle for the propane tank is very long, in order to more clearly observe the changes in the thermal physical field of the internal fluid in a shorter time, the external heat leakage is magnified by about 600 times during the simulation process and set to 5400W / m 2 , so the calculation time will be increased by 600 times accordingly. At the same time, the heat leakage is also related to the temperature difference between the fluid inside the tank and the external environment. As the temperature inside the tank rises, the temperature difference between the fluid and the external environment gradually decreases, so the heat leakage will also gradually decrease. Considering the extreme case when the temperature inside the tank rises to 300K, the temperature difference with the external environment is 0, and the heat leakage at this time will also be reduced to 0. Considering that in the temperature range from liquid nitrogen to room temperature, the thermal conductivity and other physical parameters of the insulation material are basically linearly related to the temperature. Therefore, in order to simplify the calculation, it is assumed that the change law of heat leakage with the internal fluid temperature is as follows: Figure 4 As shown, specifically q1=-26.34T1+7902, q1 represents the heat leakage, T1 represents the internal fluid temperature, and the unit is K.

[0068] In the case of continuous heat leakage from the external environment, in order to alleviate the temperature increase in the propane tank, the cold energy of the external cold source is introduced to compensate for the heat leakage. The cold energy can be input by placing coils or refrigeration plates in the tank and continuously introducing liquid nitrogen. The area of ​​the parts in the tank is set to the isothermal domain, the temperature is constant at 77K, and the output cold energy is 6000W / m 2 , the initial pressure in the propane tank is 101325Pa.

[0069] According to an embodiment of the present invention, step 200, obtaining multiple groups of temperature data within a preset time period, can be to obtain multiple groups of first temperature data within a preset time period in the absence of an external cold source; of course, it can also be to obtain multiple groups of second temperature data within the preset time period in the presence of an external cold source.

[0070] For example, in the case of continuous heat leakage from the external environment, in order to alleviate the temperature increase in the propane storage tank, it is necessary to introduce cold energy from an external cold source to compensate for the heat leakage. The coupling method of the refrigerator and the liquid hydrogen storage tank can be two ways: the refrigerator cools the cryogenic liquid and the refrigerator recondenses the cryogenic gas. Based on the size and economic considerations of the propane storage tank, this embodiment adopts the method of placing a coil in the storage tank and continuously passing liquid nitrogen to input cold energy. In order to simplify the complexity of the model, the coil is assumed to be a uniform copper refrigeration plate with a size of 1×22m, and its temperature is constantly maintained at the boiling point of liquid nitrogen, that is, 77K.

[0071] In this embodiment, Figure 5 As shown, multiple cooling forms are introduced into the two-dimensional propane storage tank, including a cooling method of introducing cooling capacity at the nitrogen in the two-dimensional propane storage tank, a cooling capacity of introducing cooling capacity at the upper part of the liquid propane in the two-dimensional propane storage tank, and a cooling capacity of introducing cooling capacity at the lower part of the liquid propane in the two-dimensional propane storage tank. That is, the copper refrigeration plate is placed at three positions, namely, the gas phase, the upper part of the liquid phase, and the lower part of the liquid phase, which respectively represent the cooling gas form, the cooling liquid upper form, and the cooling liquid lower form, as shown in FIG. Figure 5 In Figures (a), (b) and (c), the distances from the tank bottom are 19m, 12m and 2m respectively, in order to analyze the effects of cooling method and cold plate position on the stability and uniformity of temperature distribution in the propane tank.

[0072] Optionally, step 200, obtaining multiple sets of temperature data within a preset time period, specifically includes the following contents: When the two-dimensional propane storage tank has no external cooling source, multiple groups of first temperature data within a preset time period are obtained.

[0073] Specifically, the temperature field distribution: In the case of a two-dimensional propane tank without an external cooling source, the temperature inside the propane tank rises rapidly, especially in the upper area of ​​the tank, where the temperature is significantly higher than that in the lower area, forming a significant thermal stratification phenomenon. As time goes by, the thermal stratification phenomenon gradually moves downward, indicating that there is a significant temperature gradient in the gas phase region, where the nitrogen temperature in the upper part is higher than the propane temperature in the lower part.

[0074] Temperature changes over time: Temperature measuring points were set in the middle of the liquid phase, the gas-liquid interface, and the middle of the gas phase of the propane tank. At the beginning, the temperature of all measuring points was recorded as 95K, indicating the initial low temperature state inside the tank. In the following period of time, for example, 7 days, the temperatures of the three measuring points gradually rose. Among them, the temperature of the third measuring point rose the fastest, and the temperature of the first measuring point rose the slowest. After 7 days, the temperatures of the first measuring point, the second measuring point, and the third measuring point rose by 0.8K, 2.9K, and 7.5K, respectively. It can be seen that the temperature of nitrogen rose faster.

[0075] Further, such as Figure 6As shown, after executing step 300, the method further includes the following steps: Step 700: Based on the temperature distribution of the propane storage tank, determine that the heating rate of nitrogen is greater than the heating rate of liquid propane.

[0076] It can be understood that based on the temperature changes at the first temperature measuring point, the second temperature measuring point and the third temperature measuring point, the difference in thermophysical properties between nitrogen and propane is verified. Nitrogen has a smaller specific heat capacity, so when absorbing the same amount of heat, the temperature of nitrogen rises faster. Therefore, based on the influence of the difference in specific heat capacity between nitrogen and liquid propane, it is determined that the heating rate of nitrogen is greater than that of liquid propane.

[0077] Optionally, step 200, obtaining multiple sets of temperature data within a preset time period, specifically includes the following contents: Introducing various forms of cooling for two-dimensional propane tanks; For each cooling form, multiple sets of second temperature data within a preset time period are obtained.

[0078] It can be understood that the above three cooling forms are introduced into the two-dimensional propane storage tank, and under each cooling form, multiple sets of second temperature data within a preset time period are obtained; of course, three two-dimensional propane storage tanks can also be constructed, and the three cooling forms can be introduced into the three two-dimensional propane storage tanks respectively, to obtain multiple sets of second temperature data for each two-dimensional propane storage tank within a preset time period.

[0079] The multiple groups of second temperature data can be two groups, namely the first group of data and the second group of data. The first group of data includes the initial temperatures of the first temperature measuring point, the second temperature measuring point and the third temperature measuring point, and the second group of data includes the temperatures of the first temperature measuring point, the second temperature measuring point and the third temperature measuring point after a certain interval.

[0080] Comparison of temperature rise under different cooling forms: Analyze the temperature changes in the propane tank under three cooling forms. After the introduction of cold energy, the temperature rise rate in the middle of the propane liquid is lower than that of the two-dimensional propane tank without a cold source. After an interval of 7 days, the temperature of the middle of the propane liquid in the two-dimensional propane tank without a cold source has risen to 95.82K, while after the introduction of an external cold source, the temperature of the middle of the propane in the cooling gas form, the cooling liquid upper form, and the cooling liquid lower form increased by about 0.42K, 0.21K, and 0.26K, respectively. It can be seen that among the different forms of cooling effects, the cooling effect of the cooling liquid upper form is the best; therefore, placing the cold source in the propane liquid part allows more cold energy to act on the liquid, effectively enhancing the natural convection inside the propane liquid, thereby achieving a better cooling effect.

[0081] Comparison of temperature uniformity under different cooling forms: Under different cooling forms, the temperature field distribution on the 7th day shows that the temperature under the upper cooling liquid form is not only lower, but also more uniform in temperature distribution. Specifically, the overall temperature of the two phases in the tank in the cooling gas form is more uniform, while in the lower cooling liquid form, there is obvious thermal stratification in both the gas phase and the liquid phase. This is mainly because the cold source of the upper cooling liquid form is located above the liquid, so there is a mixing mechanism in the propane liquid, and its temperature distribution is more uniform than that of the lower cooling liquid form. The existence of natural convection effect can effectively improve temperature uniformity.

[0082] For example, Figure 7 As shown, after executing step 300, the method further includes the following steps: Step 800: compare multiple sets of second temperature data of multiple cooling forms, and determine the cooling method with the best temperature uniformity and / or the cooling method with the best temperature reduction effect as the target cooling method.

[0083] It can be understood that the temperature changes in the propane tank under the three cooling forms were studied, and the temperature under the cooling liquid upper form was not only lower, but the temperature distribution was also more uniform, so the cooling liquid upper form was determined as the target cooling method for the propane tank, thereby achieving better cooling effect and temperature uniformity.

[0084] The propane tank temperature rise characteristic analysis device provided by the present invention is described below. The propane tank temperature rise characteristic analysis device described below and the propane tank temperature rise characteristic analysis method described above can be referenced to each other.

[0085] The embodiment of the second aspect of the present invention provides a propane tank temperature rise characteristic analysis device, the analysis device includes a determination module, an acquisition module and a obtaining module; wherein: The determination module is used to determine multiple temperature measurement points of the two-dimensional propane storage tank, and the multiple temperature measurement points include a first temperature measurement point set at the liquid phase of the two-dimensional propane storage tank, a second temperature measurement point at the junction of the gas and liquid phases, and a third temperature measurement point of the gas phase.

[0086] The acquisition module is used to acquire multiple groups of temperature data within a preset time period, and the temperature data includes multiple temperature values ​​corresponding to multiple temperature measurement points.

[0087] The module is used to obtain the temperature distribution of the propane tank based on multiple sets of temperature data.

[0088] Figure 8 An example of a physical structure diagram of an electronic device is shown in FIG. Figure 8As shown, the electronic device may include: a processor 810, a communication interface 820, a memory 830 and a communication bus 840, wherein the processor 810, the communication interface 820 and the memory 830 communicate with each other through the communication bus 840. The processor 810 may call the logic instructions in the memory 830 to execute the propane tank temperature rise characteristic analysis method, which includes: determining multiple temperature measurement points of a two-dimensional propane tank, the multiple temperature measurement points include a first temperature measurement point set at the liquid phase of the two-dimensional propane tank, a second temperature measurement point at the junction of the gas and liquid phases, and a third temperature measurement point of the gas phase; obtaining multiple groups of temperature data within a preset time period, the temperature data include multiple temperature values ​​corresponding to the multiple temperature measurement points; based on the multiple groups of temperature data, obtaining the temperature distribution of the propane tank.

[0089] In addition, the logic instructions in the above-mentioned memory 830 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0090] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the propane storage tank temperature rise characteristic analysis method provided by the above methods, and the method includes: determining multiple temperature measurement points of a two-dimensional propane storage tank, the multiple temperature measurement points include a first temperature measurement point set at the liquid phase of the two-dimensional propane storage tank, a second temperature measurement point at the junction of the gas-liquid phase, and a third temperature measurement point of the gas phase; obtaining multiple groups of temperature data within a preset time period, the temperature data include multiple temperature values ​​corresponding to multiple temperature measurement points; based on the multiple groups of temperature data, obtaining the temperature distribution of the propane storage tank.

[0091] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to execute the propane storage tank temperature rise characteristic analysis method provided by the above-mentioned methods, the method comprising: determining multiple temperature measuring points of a two-dimensional propane storage tank, the multiple temperature measuring points comprising a first temperature measuring point disposed at the liquid phase of the two-dimensional propane storage tank, a second temperature measuring point at the junction of the gas-liquid phases, and a third temperature measuring point of the gas phase; acquiring multiple sets of temperature data within a preset time period, the temperature data comprising multiple temperature values ​​corresponding to the multiple temperature measuring points; and obtaining the temperature distribution of the propane storage tank based on the multiple sets of temperature data.

[0092] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, i.e., they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Those of ordinary skill in the art may understand and implement it without creative effort.

[0093] Through the description of the above implementation modes, those skilled in the art can clearly understand that each implementation mode can be implemented by means of software plus a necessary general hardware platform, or of course by hardware. Based on such an understanding, the above technical solution can essentially or in other words be embodied in the form of a software product that contributes to the prior art. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods of each embodiment or some parts of the embodiment.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for analyzing the heating characteristics of a propane storage tank, characterized in that: include: Determine a plurality of temperature measurement points of the two-dimensional propane storage tank, wherein the plurality of temperature measurement points include a first temperature measurement point disposed at the liquid phase of the two-dimensional propane storage tank, a second temperature measurement point at the interface between the gas and liquid phases, and a third temperature measurement point at the gas phase; Acquire multiple sets of temperature data within a preset time period, wherein the temperature data includes multiple temperature values ​​corresponding to multiple temperature measurement points; Based on the multiple groups of temperature data, the temperature distribution of the propane storage tank is obtained.

2. The method for analyzing the temperature rise characteristics of a propane storage tank according to claim 1, characterized in that: The multiple sets of temperature data include multiple sets of first temperature data, and the acquiring multiple sets of temperature data within a preset time period includes: When the two-dimensional propane storage tank has no external cold source, obtaining multiple sets of first temperature data within a preset time period; After obtaining the temperature distribution of the propane storage tank based on the multiple sets of temperature data, the method further includes: Based on the temperature distribution of the propane storage tank, it is determined that the heating rate of nitrogen is greater than the heating rate of liquid propane.

3. The method for analyzing the temperature rise characteristics of a propane storage tank according to claim 1, characterized in that: The multiple sets of temperature data include multiple sets of second temperature data, and the acquiring multiple sets of temperature data within a preset time period includes: Introducing multiple cooling forms to the two-dimensional propane tank; For each cooling form, obtaining multiple sets of second temperature data within a preset time period; After obtaining the temperature distribution of the propane storage tank based on the multiple sets of temperature data, the method further includes: The plurality of sets of second temperature data of the plurality of cooling forms are compared, and a cooling mode with the best temperature uniformity and / or a cooling mode with the best temperature reduction effect is determined as a target cooling mode.

4. The method for analyzing the temperature rise characteristics of a propane storage tank according to claim 3, characterized in that: The multiple cooling forms include a method of introducing cold energy at the nitrogen in the two-dimensional propane storage tank, a method of introducing cold energy at the upper part of the liquid propane in the two-dimensional propane storage tank, and a method of introducing cold energy at the lower part of the liquid propane in the two-dimensional propane storage tank. The target cooling method is a method of introducing cold energy at the upper part of the liquid propane in the two-dimensional propane storage tank.

5. The method for analyzing the temperature rise characteristics of a propane storage tank according to any one of claims 1 to 4, characterized in that: Before acquiring multiple sets of temperature data within a preset time period, the method further includes: Determining a heat transfer relationship of the two-dimensional propane storage tank based on the heat transfer characteristics of the two-dimensional propane storage tank; Based on the heat transfer relationship, determining the amount of heat leakage transferred from the external environment to the two-dimensional propane storage tank; Based on the heat leakage, determining boundary conditions; The step of obtaining multiple sets of temperature data within a preset time period includes: A plurality of groups of temperature data within a preset time period are acquired under the boundary conditions.

6. The method for analyzing the temperature rise characteristics of a propane storage tank according to claim 5, characterized in that: The heat transfer relationship for determining the two-dimensional propane storage tank includes: Determine the heat transfer relationship based on formula (1); （1） in, represents the amount of heat transferred; A represents the heat transfer area; k represents the heat transfer coefficient, , R1 represents the thermal resistance of thermal conduction, R2 represents the thermal resistance of convection, and R3 represents the thermal resistance of radiation; Indicates the temperature of propane in the propane tank. Indicates the temperature of the nitrogen in the propane tank.

7. The method for analyzing the temperature rise characteristics of a propane storage tank according to any one of claims 1 to 4, characterized in that: Before acquiring multiple sets of temperature data within a preset time period, the method further includes: The thermal relationship between the thermophysical parameters of liquid propane and nitrogen and the temperature is obtained, wherein the thermophysical parameters include density, thermal conductivity, and specific heat capacity.

8. The method for analyzing the temperature rise characteristics of a propane storage tank according to any one of claims 1 to 4, characterized in that: The structural parameters of the two-dimensional propane storage tank remain constant, and the structural parameters include at least one of the thickness of the insulation layer, the heat leakage in each direction of the tank body, the outer wall temperature of the tank body, the tank body pressure, and the tank body material.

9. A propane tank temperature rise characteristic analysis device, characterized in that: include: A determination module, used to determine a plurality of temperature measurement points of the two-dimensional propane storage tank, wherein the plurality of temperature measurement points include a first temperature measurement point set at the liquid phase of the two-dimensional propane storage tank, a second temperature measurement point at the junction of the gas-liquid phase, and a third temperature measurement point of the gas phase; An acquisition module, used to acquire multiple sets of temperature data within a preset time period, wherein the temperature data includes multiple temperature values ​​corresponding to multiple temperature measurement points; The obtaining module is used to obtain the temperature distribution of the propane storage tank based on the multiple groups of temperature data.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the method for analyzing the temperature rise characteristics of a propane storage tank as described in any one of claims 1 to 9 is implemented.

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