Temperature simulation prediction method of thermal insulation oil tank based on iterative method

Abstract

A method for simulating and predicting the temperature of an anti-insulated oil tank based on an iteration method belongs to the technical field of instantaneous oil temperature prediction for oil-storage wings and rudder wings. The present invention addresses the problem of difficulty in predicting the instantaneous oil temperature of oil-storage wings and rudder wings of aircraft. The method includes abstracting the wing or rudder wing with a fuel tank into three parts: the outer surface, the middle insulation layer, and the inner fuel tank; establishing a three-dimensional model of the abstracted wing and rudder wing; then performing network division to obtain a meshed three-dimensional model; and then, through an iterative method, obtaining a curve composed of multiple piecewise functions, i.e., the final temperature prediction curve. The present invention is used for fuel tank temperature prediction.

Description

Technical Field

[0001] The invention relates to an iterative method-based temperature simulation prediction method for a heat-insulating oil tank, and belongs to the technical field of instantaneous oil temperature prediction for oil storage wings and rudder wings. Background Art

[0002] With the continuous development of aerospace technology, hypersonic aircraft are constantly being updated, and their flight speeds are increasing. Due to the "thermal barrier effect", the faster the flight speed, the higher the temperature of the skin. This has a significant impact on the safety of the aircraft's fuel tanks. Therefore, the fuel tank structures of hypersonic aircraft are generally treated with heat insulation.

[0003] However, different structures, flight speeds, and fuel storage capacities all affect the effectiveness of thermal insulation, significantly impacting the design of fuel tanks and thermal insulation structures. Traditional fuel tank temperature measurement typically utilizes thermocouples, infrared, and other methods. This is not only inconvenient, but also limits the timeline and spatial region of measurement, hindering understanding of temperature variations. Simulation methods offer significant advantages, enabling full-process analysis across timelines and spatial points. However, current simulation methods are immature and cannot adjust to changes in the conduction coefficient in real time, resulting in insufficient prediction accuracy. An accurate thermal insulation tank prediction method is urgently needed, as it is crucial for hypersonic vehicle design.

[0004] Currently, the oil temperature of the fuel storage wings and rudders of such aircraft is generally measured experimentally using thermocouples, infrared, or through simple predictions based on production experience. Nowadays, various aircraft operate in different environments, and the requirements for fuel tank oil temperature at different time periods during the entire flight process are even more different. Therefore, when faced with new thermal insulation materials and structures for fuel storage wings and rudders, there is a lack of an effective means of predicting oil temperature, especially the oil temperature at a specific point in time. Using traditional design experiments to measure oil temperature not only greatly increases the research and development costs of new aircraft, but also seriously hinders the pace of aircraft design. Therefore, there is an urgent need for an effective method to predict the instantaneous oil temperature of fuel storage wings and rudders to detect the oil temperature variation patterns of the oil storage structure in advance. Summary of the Invention

[0005] Aiming at the problem that it is difficult to predict the instantaneous oil temperature of aircraft oil storage wings and rudder wings, the present invention provides a temperature simulation prediction method for an anti-insulation oil tank based on an iterative method.

[0006] The present invention provides an iterative method for simulating and predicting the temperature of an anti-insulated oil tank, comprising:

[0007] Abstract the wing or rudder with fuel tank into three parts: outer surface, middle insulation layer and inner fuel tank, and build the three-dimensional model of the abstracted wing and rudder;

[0008] Meshing the three-dimensional model of the wing and rudder based on material properties to obtain a meshed three-dimensional model;

[0009] The thermodynamic simulation time T is set, the flight ambient temperature is inputted at the outermost side of the outer surface of the three-dimensional model after meshing, the initial forced convection coefficient h0 is inputted at the inner surface of the inner fuel tank, and the initial value of the oil temperature c0 is set, and the initial temperature change curve is calculated; the vertical line corresponding to the time point t1 at which the heating rate approaches zero in the initial temperature change curve is used as the convection forced line L0, and the convection forced line L0 divides the initial temperature change curve into two time periods: t0 to t1 and t1 to T; the time period t0 to t1 of the initial temperature change curve is fitted as the first section of the fuel tank heating curve; in the time period t0 to t1, the oil temperature is heated from c0 to c1 at a fixed heating rate;

[0010] Then, the current forced convection coefficient h1 is input into the inner surface of the inner tank of the meshed three-dimensional model, and the current oil temperature is set to c1. The current temperature change curve for the time period t0 to t1 based on the initial temperature change curve is calculated. The vertical line corresponding to the time point t2 where the temperature rise rate drops the most in the current temperature change curve is used as the convection forced line L1. The convection forced line L1 further divides the time period t1 to T of the current temperature change curve into two time periods t1 to t2 and t2 to T. The time period t1 to t2 of the current temperature change curve is fitted as the second section of the tank temperature rise curve. In the time period t1 to t2, the oil temperature rises from c1 to c2 at a fixed heating rate.

[0011] Continue iterating until the convection force line Ln corresponding to time T is obtained, the nth segment of the fuel tank temperature rise curve is fitted, the complete fitted fuel tank temperature rise curve is obtained, and the fuel tank temperature value at time T is determined.

[0012] According to the temperature simulation prediction method of the anti-insulated fuel tank based on the iteration method of the present invention, the outer surface corresponds to all components of the wing or rudder exposed to the outer air and the connection parts with the aircraft;

[0013] The inner oil tank corresponds to the oil storage tank;

[0014] The middle thermal insulation layer corresponds to all components between the outer surface and the inner oil tank.

[0015] According to the anti-insulation oil tank temperature simulation prediction method based on the iteration method of the present invention, the three-dimensional model of the wing and the rudder wing is established using 3D modeling software.

[0016] According to the temperature simulation prediction method of the anti-insulation oil tank based on the iteration method of the present invention, the temperature change curve of the three-dimensional model after meshing is calculated based on the transient thermal analysis of Ansys software.

[0017] According to the anti-insulation oil tank temperature simulation prediction method based on the iteration method of the present invention, the current forced convection coefficient h1 is the convection coefficient of the remaining oil and gas in the current oil storage tank after mixing.

[0018] According to the anti-insulation oil tank temperature simulation prediction method based on the iteration method of the present invention, the oil is in a liquid state, a gaseous state or a gas-liquid mixed state.

[0019] According to the anti-insulation oil tank temperature simulation prediction method based on the iteration method of the present invention, the oil is in a heat dissipation state of natural convection.

[0020] According to the temperature simulation prediction method of the heat-insulated oil tank based on the iterative method of the present invention, the forced convection coefficient of each section is expressed as h(n-1), h(n-1) is the average convection coefficient in the oil tank during the time period t(n-1) to tn; n is not less than 3.

[0021] According to the anti-insulation oil tank temperature simulation prediction method based on the iteration method of the present invention, the thermodynamic simulation time T is not less than 100s.

[0022] According to the anti-insulation oil tank temperature simulation prediction method based on the iterative method of the present invention, the fitting method for obtaining the oil tank temperature rise curve is: selecting no less than 5 points that do not contain obvious anomalies on the corresponding segment of the temperature change curve, using the least squares method to perform linear regression analysis, and obtaining the corresponding fitting segment.

[0023] Beneficial effects of the present invention: The present invention proposes a simulation prediction method that can modify parameters in different time periods to approximate the actual measured temperature of the fuel tank by using simulation software and iterative thinking.

[0024] The method disclosed herein is used to predict the oil temperature of oil-storage wings and rudder wings. It can predict the oil temperature of these wings at any time in a high-temperature environment without designing experiments. The predicted segmented temperature curve not only determines the instantaneous temperature at a specific point in time but also allows for a clearer observation of the oil temperature variation, making it easier and more convenient to evaluate insulation materials and their insulation effectiveness.

[0025] Compared to traditional, crude simulation methods, this invention uses an iterative, step-by-step approach to approximate the actual temperature rise curve. This ensures the accuracy of the final predicted temperature while also addressing the inability of traditional thermal simulations to predict instantaneous temperatures. The iteratively generated simulated temperature cloud map also reveals abnormal oil temperatures and pinpoints the structural locations where thermal bridges form, leading to temperature difficulties. This significantly reduces the trial-and-error cost of optimizing the insulation structures of the oil storage wing and rudder wing, facilitating the optimization of inappropriate insulation structures.

[0026] When applied to novel thermal insulation materials and structures for oil-storage wings and rudders, the proposed method can accurately predict the oil temperature distribution of these wings and rudders at different time points. It can also quickly and easily predict the temporal evolution of oil temperature in complex oil-storage structures. This significantly reduces the time and effort required to validate the rationality of rudder and wing oil-storage structures or insulation results, while providing more detailed optimization recommendations. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of a rudder wing with a fuel tank;

[0028] Figure 2 It will Figure 1 Schematic diagram of the split after abstract processing; in the figure, 11 is the outer surface, 12 is the middle insulation layer, and 13 is the inner fuel tank;

[0029] Figure 3 This is a schematic diagram of the mesh division of the 3D model of the rudder wing with fuel tank;

[0030] Figure 4 Schematic diagram of the initial temperature change curve obtained by a simulation using the method of the present invention; c in the figure represents the oil temperature;

[0031] Figure 5 This is the predicted temperature change diagram after the present invention finally completes the iteration;

[0032] Figure 6 Schematic diagram of a rudder wing with a fuel tank according to the first embodiment;

[0033] Figure 7 yes Figure 6 Schematic diagram of splitting after abstract processing;

[0034] Figure 8 Schematic diagram of mesh division of the oil storage rudder wing after abstract processing in Example 1;

[0035] Figure 9 1 is a schematic diagram of an initial temperature change curve in a simulation performed in Example 1;

[0036] Figure 10 This is a schematic diagram of the linear curve of the fuel tank temperature rise after complete fitting in Example 1;

[0037] Figure 11 This is the final predicted temperature change curve result diagram of Example 1;

[0038] Figure 12 This is a temperature distribution cloud diagram of the final temperature prediction of Example 1;

[0039] Figure 13 This is a physical diagram of the temperature measurement experimental design in the comparative experiment;

[0040] Figure 14 This is a temperature curve chart after actual testing in the comparative experiment. DETAILED DESCRIPTION

[0041] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0042] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0043] The present invention will be further described below with reference to the accompanying drawings, but is not intended to limit the present invention.

[0044] Specific implementation method 1. Combination Figures 1 to 5 As shown, the present invention provides a temperature simulation prediction method for an anti-insulation oil tank based on an iterative method, comprising:

[0045] Abstract the wing or rudder with fuel tank into three parts: outer surface, middle insulation layer and inner fuel tank, and build the three-dimensional model of the abstracted wing and rudder;

[0046] Meshing the three-dimensional model of the wing or rudder according to basic material properties of different components of the wing or rudder to obtain a meshed three-dimensional model;

[0047] The thermodynamic simulation time T is set, the flight ambient temperature is inputted at the outermost side of the outer surface of the three-dimensional model after meshing, the initial forced convection coefficient h0 is inputted at the inner surface of the inner fuel tank, and the initial value of the oil temperature c0 is set, and the initial temperature change curve is calculated; the vertical line corresponding to the time point t1 at which the heating rate approaches zero in the initial temperature change curve is used as the convection forced line L0, and the convection forced line L0 divides the initial temperature change curve into two time periods: t0 to t1 and t1 to T; the time period t0 to t1 of the initial temperature change curve is fitted as the first section of the fuel tank heating curve; in the time period t0 to t1, the oil temperature is heated from c0 to c1 at a fixed heating rate;

[0048] Then, the current forced convection coefficient h1 is input into the inner surface of the inner tank of the meshed three-dimensional model, and the current oil temperature is set to c1. The current temperature change curve for the time period t0 to t1 based on the initial temperature change curve is calculated. The vertical line corresponding to the time point t2 where the temperature rise rate drops the most in the current temperature change curve is used as the convection forced line L1. The convection forced line L1 further divides the time period t1 to T of the current temperature change curve into two time periods t1 to t2 and t2 to T. The time period t1 to t2 of the current temperature change curve is fitted as the second section of the tank temperature rise curve. In the time period t1 to t2, the oil temperature rises from c1 to c2 at a fixed heating rate.

[0049] Continue iterating until the convection force line Ln corresponding to time T is obtained, the nth segment of the fuel tank temperature rise curve is fitted, the complete fitted fuel tank temperature rise curve is obtained, and the fuel tank temperature value at time T is determined.

[0050] After meshing, the parameters of the 3D model can be input using the Transient Thermal function in Ansys software. In the fitted tank temperature rise curve, the section from t0 to t1 is a linear temperature rise curve. During the t1 period, the oil temperature rises from c0 to c1 at a fixed rate. Using the quadratic command in Ansys software, the current fitted curve is input into a new thermal simulation. In this case, the internal oil temperature will rise from c0 to c1 from 0 to t1, and remain constant at c1 from t1 to T. The convection coefficients from 0 to t1 are h0, and from t1 to T are h1. h1 represents the new convection coefficient due to the mixture of oil and gas in the remaining tank after the oil volume is reduced. A new temperature curve is calculated again, divided into three sections: t0 to t1, t1 to t2, and t2 to T, by the convection force lines L1 and L0. L1 is the vertical line at the point of the maximum drop in the temperature rise rate in the temperature curve.

[0051] Then, a temperature change curve is constructed based on the iteration results and the final temperature prediction value is output:

[0052] Repeat this iterative process until the nth iteration. At this point, the oil temperature increases linearly at a constant rate for each segment from 0 to t1, t1 to t2, and so on to t(n-1) to T, ultimately reaching cn. The resulting curve, composed of multiple piecewise functions, is the final temperature prediction curve. The resulting final oil temperature cn is the predicted final oil temperature of the wing or rudder oil storage tank at the specified time. The prediction curve can also be used to observe oil temperature predictions at other time points.

[0053] Combine Figure 2 As shown, the outer surface corresponds to all components of the wing or rudder exposed to the outer air and the connection parts with the aircraft;

[0054] The inner oil tank corresponds to the oil storage tank;

[0055] The middle thermal insulation layer corresponds to all components between the outer surface and the inner oil tank, such as thermal insulation filling materials, structural support skeleton, etc.

[0056] In this embodiment, when meshing the outer surface, the middle insulation layer, and the inner fuel tank, the meshing of each abstract component needs to remain independent of each other.

[0057] Furthermore, the three-dimensional models of the wings and rudder wings are established using any 3D modeling software.

[0058] As an example, according to the required model size, the three-dimensional model of the wing and rudder is created using Solidworks software.

[0059] As an example, the temperature variation curve of the three-dimensional model after meshing is calculated based on the transient thermal analysis of Ansys software.

[0060] In this embodiment, the current forced convection coefficient h1 is the convection coefficient of the remaining oil and gas in the current oil storage tank after mixing.

[0061] The oil needs to be kept in a liquid, gaseous or gas-liquid mixed state at all times.

[0062] The oil is in a state of heat dissipation by natural convection, without any additional heat dissipation device.

[0063] As an example, the thermodynamic simulation time T is not less than 100 s.

[0064] As an example, 300°C≦ambient temperature C≦900°C.

[0065] In this embodiment, the ambient temperature C and the initial value of the oil temperature c0 can both be given by actual flight service conditions.

[0066] All convection coefficients can be calculated or given based on the aircraft's state, fuel storage materials, and specific fuel consumption conditions.

[0067] Furthermore, a fitting method for obtaining the fuel tank temperature rise curve is as follows: selecting no less than 5 points without obvious anomalies on the corresponding segment of the temperature change curve, performing linear regression analysis using the least squares method or other statistical tools and programming tools, and obtaining the corresponding fitting segment.

[0068] In this embodiment, the forced convection coefficient of each section is expressed as h(n-1), where h(n-1) is the average convection coefficient in the fuel tank during the time period t(n-1) to tn; and n is not less than 3.

[0069] In this embodiment, the temperature change curve obtained by iteration is not necessarily equal in each time period. The curve obtained in each iteration is fitted into a linear curve before entering the next iteration. The final temperature prediction curve is a piecewise composite function composed of multiple linear functions.

[0070] The technical solution of the method of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0071] Example 1, combined with Figures 6 to 12 Specific instructions:

[0072] A temperature simulation prediction method for an anti-insulation oil tank based on an iterative method is carried out in the following steps:

[0073] Step 1: Abstract processing and modeling of the wings and rudders with fuel tanks;

[0074] Will Figure 6 The rudder with fuel tank is abstractly composed of three parts: the outer surface 11, the middle insulation layer 12, and the inner fuel tank 13. The outer surface includes all components of the rudder exposed to the outside air and the connection with the aircraft; the inner fuel tank refers to the fuel storage tank; the middle insulation layer includes insulation filling materials and a structural support frame. The abstracted rudder 3D model is created using Solidworks software, as shown in the following figure: Figure 7 As shown;

[0075] Step 2: Preliminary thermal simulation of fuel tank temperature:

[0076] According to the basic material properties of different components of the wing or rudder, the three-dimensional model is divided into grids. Figure 8 As shown, the transient thermal function of Ansys software was used to input the thermodynamic simulation time of 1000s, the temperature encountered during flight was input as 650°C on the outermost side of the outer layer 11, and forced convection was input on the inner surface of the inner layer tank 13, with a convection coefficient of 5×10 5 W / mm·℃, the initial temperature of the internal oil temperature is constant at 22℃. After calculating the results, the temperature change curve 21 is obtained, as shown in Figure 9 shown.

[0077] Step 3: Post-processing and iterative process of simulation results:

[0078] According to the temperature change curve 21 of the initial simulation results, it is divided into two parts: 0-249s and 249s-1000s by the convection force line L0. L0 is the vertical line at the time point when the heating rate of the temperature change curve 21 approaches zero. The 0-249s section is fitted into a linear heating curve, as shown in Figure 10As shown, it means that in the time period from 0 to 249 seconds, the oil temperature rises from 22°C to 30.22°C at a heating rate of 0.032°C / s. Using the quadratic command of Ansys software, this result is input into a new thermal simulation. At this time, the internal oil temperature will rise from 22°C to 30.22°C from 0 to 249 seconds and remain at 30.22°C from 249 seconds to 1000 seconds. The convection coefficient from 0 to 249 seconds is 5×105 W / mm·°C, and the convection coefficient from 249 seconds to 1000 seconds is 4.8×10 5 W / mm·°C. The results are calculated again to obtain the temperature change curve 22. This time, the temperature change curve 22 is divided into three parts: 0-249s, 249-529s, and 529s-1000s by the convection force lines L1 and L0. L1 is the vertical line where the temperature change curve 22 has the maximum drop in the heating rate.

[0079] Step 4: Construct a temperature change curve based on the iteration results and output the final temperature prediction value:

[0080] Repeat the above iterative process until the third iteration. At this time, the oil temperature is linearly increased at a constant heating rate of 0.032℃ / s, 0.035℃ / s, 0.036℃ / s, and 0.038℃ / s in the intervals of 0-249s, 249-529s, 529s-768s, and 768s-1000s, respectively, and the oil temperature is finally raised to 61.2℃. The resulting curve composed of multiple piecewise functions, i.e., the final temperature prediction curve, is shown in Fig. Figure 11 As shown in the figure, the final oil temperature c4 is the predicted final oil temperature of the wing or rudder oil storage tank at the specified time point. The oil temperature prediction at other time points can also be observed based on the prediction curve. And further obtain Figure 12 The temperature distribution cloud map shown can be used to observe abnormal oil temperature conditions and provide specific structural locations where thermal bridges are formed and the temperature is difficult to control.

[0081] Comparative experiment: Combination Figure 13 Specifically, this experiment adopts the traditional actual test measurement method to design and carry out the actual measurement test of the thermal insulation of the simulated rudder wing under the same parameters as the embodiment. Its various parameters are the same as those in the embodiment 1. At the same time, for the safety of the experiment, a large-scale heating chamber is selected instead of a small heating furnace to simulate the external high temperature of 650°C. Finally, the actual temperature rise curve is as follows Figure 14 It is not difficult to find that the results of the traditional design actual test are basically consistent with the prediction results of Example 1. However, the method of the present invention greatly simplifies the process of predicting the thermal insulation properties of rudder and wing structures, greatly reducing the cost of evaluating and predicting the thermal insulation performance of different structures, thereby accelerating the design and optimization of the thermal insulation properties of rudder and wing structures.

[0082] Beyond aerospace applications, other fields, such as rockets and missiles, can also employ the solutions and solutions of this invention when faced with the challenge of instantaneous temperature prediction in thermally insulated fuel tanks. Similar methods and solutions utilizing iterative methods for temperature prediction are also within the scope of this patent.

[0083] The present application has been described in detail above with reference to specific embodiments and exemplary embodiments, and these descriptions are not to be construed as limiting the present application. Those skilled in the art will appreciate that, without departing from the spirit and scope of the present application, various equivalent substitutions, modifications, or improvements may be made to the technical solutions and implementations of the present application, all of which fall within the scope of the present application. The scope of protection of the present application shall be subject to the appended claims.

Claims

1. A temperature simulation prediction method for an anti-insulation oil tank based on an iterative method, characterized in that: include, Abstract the wing or rudder with fuel tank into three parts: outer surface, middle insulation layer and inner fuel tank, and build the three-dimensional model of the abstracted wing and rudder; Meshing the three-dimensional model of the wing and rudder based on material properties to obtain a meshed three-dimensional model; The thermodynamic simulation time T is set, the flight ambient temperature is inputted at the outermost side of the outer surface of the three-dimensional model after meshing, the initial forced convection coefficient h0 is inputted at the inner surface of the inner fuel tank, and the initial value of the oil temperature c0 is set, and the initial temperature change curve is calculated; the vertical line corresponding to the time point t1 at which the heating rate approaches zero in the initial temperature change curve is used as the convection forced line L0, and the convection forced line L0 divides the initial temperature change curve into two time periods: t0 to t1 and t1 to T; the time period t0 to t1 of the initial temperature change curve is fitted as the first section of the fuel tank heating curve; in the time period t0 to t1, the oil temperature is heated from c0 to c1 at a fixed heating rate; Then, the current forced convection coefficient h1 is input into the inner surface of the inner tank of the meshed three-dimensional model, and the current oil temperature is set to c1. The current temperature change curve for the time period t0 to t1 based on the initial temperature change curve is calculated. The vertical line corresponding to the time point t2 where the temperature rise rate drops the most in the current temperature change curve is used as the convection forced line L1. The convection forced line L1 further divides the time period t1 to T of the current temperature change curve into two time periods t1 to t2 and t2 to T. The time period t1 to t2 of the current temperature change curve is fitted as the second section of the tank temperature rise curve. In the time period t1 to t2, the oil temperature rises from c1 to c2 at a fixed heating rate. Continue iterating until the convection force line Ln corresponding to time T is obtained, the nth segment of the fuel tank temperature rise curve is fitted, the complete fitted fuel tank temperature rise curve is obtained, and the fuel tank temperature value at time T is determined.

2. The temperature simulation prediction method for an anti-insulated oil tank based on an iterative method according to claim 1 is characterized in that: The outer surface corresponds to all components of the wing or rudder exposed to the outer air and the connection parts with the aircraft; The inner oil tank corresponds to the oil storage tank; The middle thermal insulation layer corresponds to all components between the outer surface and the inner oil tank.

3. The temperature simulation prediction method of the anti-insulation oil tank based on the iteration method according to claim 1 is characterized in that: The three-dimensional models of the wing and rudder are established using 3D modeling software.

4. The method for predicting the temperature of an anti-insulated oil tank based on an iterative method according to claim 1, characterized in that: The temperature change curve of the three-dimensional model after meshing is calculated based on transient thermal analysis of Ansys software.

5. The temperature simulation prediction method for an anti-insulated oil tank based on an iterative method according to claim 1 is characterized in that: The current forced convection coefficient h1 is the convection coefficient of the remaining oil and gas in the current oil storage tank after mixing.

6. The temperature simulation prediction method for an anti-insulated oil tank based on an iterative method according to claim 5 is characterized in that: The oil is in liquid, gaseous or gas-liquid mixed state.

7. The temperature simulation prediction method for an anti-insulated oil tank based on an iterative method according to claim 5 is characterized in that: The oil is in a heat dissipation state of natural convection.

8. The method for temperature simulation prediction of an anti-insulated oil tank based on an iterative method according to claim 1, characterized in that: The forced convection coefficient of each section is expressed as h(n-1), where h(n-1) is the average convection coefficient in the fuel tank during the time period t(n-1) to tn; n is not less than 3.

9. The method for simulating and predicting the temperature of an anti-insulated oil tank based on an iterative method according to claim 1, characterized in that: The thermodynamic simulation time T is not less than 100s.

10. The method for simulating and predicting the temperature of an anti-insulated oil tank based on an iterative method according to claim 1, characterized in that: The fitting method for obtaining the fuel tank temperature rise curve is as follows: selecting no less than 5 points without obvious anomalies on the corresponding segment of the temperature change curve, performing linear regression analysis using the least squares method, and obtaining the corresponding fitting segment.

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