Two-dimensional charging reverse design method for solid engine

Abstract

The invention discloses a two-dimensional charging reverse design method for a solid engine. The method comprises the following steps that the function relation between the combustion perimeter and the combustion thickness is obtained; obtaining a function relationship between any point on the combustion curve and the intersection point; on the basis of the function relation between the combustion perimeter and the combustion thickness, according to the function relation between any point on the combustion curve and the intersection point and the inclination angle of the elimination curve, the inclination angle and coordinates of the tail end point of the combustion curve are obtained; based on the function relation between any point on the combustion curve and the intersection point, according to the coordinates of the intersection point, the inclination angle and coordinates of the corresponding point on the combustion curve are obtained; and outputting all combustion curve points, obtaining an equation of a combustion curve through fitting processing, and carrying out engine charging design. According to the two-dimensional charge reverse design method for the solid engine, the selection of charge types and structure parameters is not needed, a large amount of repetition of inexperienced personnel is avoided, and the dependence on the experience of the charge types is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of solid rocket engines, and in particular relates to a method for reverse designing two-dimensional charge of a solid engine. Background Art

[0002] Solid rocket engines, hereinafter referred to as "solid engines", are rocket propulsion devices that use solid propellants. They have many advantages, such as simple structure, high reliability, ease of use, good acceleration, and fast emergency response speed. They are the first choice for advanced strategic and tactical weapon system power devices. Due to different mission requirements, solid rocket engines need to be able to produce expected thrust that changes over time. The thrust-time curve of a solid engine is affected by the structure of the charge. When the charge structure is determined, it can only produce a specific thrust-time curve according to the law after being ignited. In order to achieve the overall thrust requirement, the charge needs to be designed.

[0003] Two-dimensional charge is a charge structure in which the channel profile is completely consistent in each cross section along the axis of the engine combustion chamber. Typical charge shapes in this category include star-shaped, wheel-shaped, etc. Figure 1 , Figure 2 . In general, the outer surface of the charge is non-combustible, while the inner surface and end surface are combustible. When the charge combustion does not occur, it follows the law of parallel layer movement, that is, the combustion surface moves along its normal to the side with the charge. Therefore, once the charge structure is determined, the movement law of its combustion surface is also determined. The engine thrust is related to the combustion chamber pressure, and the combustion chamber pressure is mainly affected by the combustion area. Therefore, the change law of the engine thrust over time is affected by the charge type.

[0004] The current charge design method is to select the appropriate category of charge based on experience, determine its structural parameters, and perform internal ballistic calculations on the charge, that is, calculate the combustion chamber pressure, engine thrust, etc., and then compare it with the overall thrust-time curve. If the requirements are not met, it will be iterated to modify the charge structure parameters, or change the charge type until the requirements are met. This method can be called "forward design", which requires the designer to first determine the charge type and structural parameters, then obtain the thrust-time curve, and then compare it with the required indicators. This process requires the designer to have a lot of experience, and the results obtained are usually greatly deviated from the target. If the deviation is to be reduced, a lot of iterations are required, which is time-consuming.

[0005] Therefore, it is urgent to propose a reverse design method for two-dimensional solid rocket charge to reduce dependence on designer experience and shorten design time. Summary of the invention

[0006] In order to solve the above technical problems, the present invention proposes a two-dimensional solid rocket charge reverse design method, which adopts the idea of ​​"reverse design", that is, the required thrust-time curve is analyzed and converted into the combustion surface-thickness curve required by the charge design profession, and then the charge structure is derived by determining the geometric structure and calculation formula. This method reduces the number of iterations and the reliance on experience to solve the problems existing in the above-mentioned prior art.

[0007] To achieve the above object, the present invention provides a method for reverse design of two-dimensional charge of a solid rocket motor, comprising the following steps:

[0008] Cutting off the cross section of each inner hole channel of the two-dimensional charge, and obtaining the combustion curve and the elimination curve on the cross section;

[0009] Obtain the functional relationship between the burning circumference and the burning meat thickness;

[0010] Selecting any point on the combustion curve, and moving the point along the normal direction to the elimination curve to obtain an intersection with the elimination curve;

[0011] Obtaining a functional relationship between any point on the combustion curve and the intersection point;

[0012] Based on the functional relationship between the combustion circumference and the combustion meat thickness, according to the functional relationship between any point on the combustion curve and the intersection point and the inclination angle of the elimination curve, the inclination angle and coordinates of the end point of the combustion curve are obtained;

[0013] Based on the functional relationship between any point on the combustion curve and the intersection point, and according to the coordinates of the intersection point, the inclination angle and coordinates of any point on the combustion curve are obtained;

[0014] Outputting all combustion curve points, and obtaining the equation of the combustion curve through fitting processing;

[0015] Based on the equation of the combustion curve, the engine charge design is carried out.

[0016] Optionally, before acquiring the combustion curve and the elimination curve on the cross section, the method further includes: establishing a coordinate system on the cross section.

[0017] Optionally, the elimination curve is the symmetry axis of the charge structure, or is the flame retardant wall surface of the charge structure.

[0018] Optionally, the functional relationship between the burning circumference and the burning meat thickness is as follows:

[0019]

[0020] Among them, S bis the burning circumference, u is the burning meat thickness, is the inclination angle of the tangent at any point on the combustion curve, is the inclination angle of the end point of the combustion curve, is the inclination angle of the intersection point on the elimination curve.

[0021] Optionally, the functional relationship between any point on the combustion curve and the intersection point is as follows:

[0022]

[0023] Among them, g(x) is the elimination curve equation, f(x) is the combustion curve equation, and x D is the horizontal coordinate of the intersection point on the elimination curve.

[0024] Optionally, before outputting all the combustion curve points, the method further includes: when the combustion thickness is zero, obtaining the coordinates of the starting point of the elimination curve, and comparing the coordinates of the starting point of the elimination curve and the coordinates of the end point of the combustion curve with the combustion boundary conditions; when the combustion boundary conditions are not met, continuing to iterate the combustion curve points based on the functional relationship between the combustion circumference and the combustion thickness until the combustion boundary conditions are met, and outputting all the combustion curve points.

[0025] Optionally, based on the equation of the combustion curve, the process of carrying out engine charge design includes: based on the equation of the combustion curve, obtaining the combustion circumference of the combustion curve, and obtaining the combustion area based on the product of the combustion circumference and the charge length; based on the functional relationship between the combustion circumference and the combustion thickness, obtaining the functional relationship between the combustion area and the combustion thickness; based on the functional relationship between the combustion area and the combustion thickness, obtaining the thrust-time curve and the pressure-time curve, and carrying out engine charge design based on the thrust-time curve and the pressure-time curve.

[0026] The present invention also provides an electronic device, comprising: a memory and a processor; the memory is used to store a program; the processor is used to execute the program to implement each step of the solid motor two-dimensional charge reverse design method.

[0027] The present invention also provides a readable storage medium on which a computer program is stored. When the computer program is executed by a processor, each step of the reverse design method of a two-dimensional charge of a solid motor is implemented.

[0028] Compared with the prior art, the present invention has the following advantages and technical effects:

[0029] The solid motor two-dimensional charge reverse design method proposed by the present invention does not need to select charge type and structural parameters, thus avoiding a large number of repetitions for inexperienced personnel and reducing dependence on experience with charge type.

[0030] After analyzing the requirements, the present invention can obtain a structure that meets the requirements through a calculation formula, and the structure can well meet the requirements, reduce the number of iterations, and save calculation time. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0032] Figure 1 Schematic diagram of a four-pointed star-shaped charge in the background technology of the present invention, wherein (a) is a schematic diagram of a cross section of the four-pointed star, and (b) is a schematic diagram of a longitudinal section of the four-pointed star;

[0033] Figure 2 Schematic diagram of a four-spoke wheel-shaped charge in the background technology of the present invention, (a) is a schematic diagram of a cross-section of the four-spoke wheel-shaped charge, and (b) is a schematic diagram of a longitudinal section of the four-spoke wheel-shaped charge;

[0034] Figure 3 This is a reverse design implementation flow chart of an embodiment of the present invention;

[0035] Figure 4 A schematic diagram of a coordinate system according to an embodiment of the present invention;

[0036] Figure 5 is a representation of a combustion curve of an embodiment of the present invention in a coordinate system;

[0037] Figure 6 The figure is a numerical calculation flow chart of an embodiment of the present invention. DETAILED DESCRIPTION

[0038] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0039] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0040] like Figure 3 As shown, in this embodiment, a method for reverse designing a two-dimensional charge of a solid rocket motor is provided, comprising the following steps:

[0041] Cutting off the cross section of each inner hole channel of the two-dimensional charge, and obtaining the combustion curve and the elimination curve on the cross section;

[0042] Obtain the functional relationship between the burning circumference and the burning meat thickness;

[0043] Selecting any point on the combustion curve, and moving the point along the normal direction to the elimination curve to obtain an intersection with the elimination curve;

[0044] Obtaining a functional relationship between any point on the combustion curve and the intersection point;

[0045] Based on the functional relationship between the combustion circumference and the combustion meat thickness, according to the functional relationship between any point on the combustion curve and the intersection point and the inclination angle of the elimination curve, the inclination angle and coordinates of the end point of the combustion curve are obtained;

[0046] Based on the functional relationship between any point on the combustion curve and the intersection point, the inclination angle and coordinates of the corresponding point on the combustion curve are obtained according to the coordinates of the intersection point;

[0047] Outputting all combustion curve points, and obtaining the equation of the combustion curve through fitting processing;

[0048] Based on the equation of the combustion curve, the engine charge design is carried out.

[0049] As a specific embodiment, the process of obtaining the functional relationship between the burning circumference and the burning meat thickness includes:

[0050] Each inner hole channel of the two-dimensional charge has a constant cross section, that is, the cross section of the inner cavity is completely consistent on each cross section. Take one of the cross sections and calculate the circumference of the curve intercepted by the burning surface on the interface, that is, the combustion circumference S, multiplied by the charge length L p The combustion area A can be obtained b ,Right now:

[0051] A b =S·L p .

[0052] In order to solve the combustion circumference S, a coordinate system is established on the cross section, such as Figure 4 As shown in the figure, taking a star-shaped charge with three star corners as an example, any curve can be expressed by an equation in the coordinate system. Assuming that any two-dimensional charge, on a certain cross section, the burning surface is intercepted to form a certain combustion curve as shown in the figure below: Figure 5 shown.

[0053] It can be considered that the intersection of the combustion curve and the elimination curve is the elimination point, and the part of the combustion curve that exceeds the elimination curve disappears after the intersection. The elimination curve can be a virtual curve formed by the intersection of the adjacent combustion curve and it, or it can be a flame-retardant wall in the charge.

[0054] Furthermore, adjacent combustion curves intersect during the moving process, resulting in no propellant in the moving direction of the intersecting curves. The burning surface cannot continue to burn and move, and the corresponding combustion curve disappears. Under any moving distance u, the curve formed by a series of intersections is called an elimination curve.

[0055] like Figure 5 As shown, curve AC is the combustion curve, AD is the elimination curve, point B is an arbitrary point on the combustion curve, point D is the intersection of point B and the elimination curve along the normal direction, the distance between BD is u, and the inclination angle of the tangent at point B is Point C is the end point of the curve, and the inclination angle The inclination angle of point D on the elimination curve is

[0056] After the drug type is determined, the burning area A b The burning length S of the curve is determined by the burning thickness u. b It is also related to the burning meat thickness u, so it can be considered that the burning circumference S b is a function of the burning meat thickness u, written as S b (u). Then the relationship between the combustion circumference and various parameters is as follows:

[0057]

[0058] Reverse Design b =S b (u) is a known equation, that is, the target combustion circumference-combustion meat thickness curve. The unknown quantity in the above formula is Third, since the elimination curves are mostly the flame-retardant wall of the charge and the symmetry axis of the charge structure, the elimination curves are subject to the requirements of the charge design outer contour, which is a constraint requirement put forward by the overall engine designer to the charge designer, as well as the influence of the designer's ideas on the number of symmetries. Therefore, the elimination curve can be used as a known condition determined by a designer based on boundary constraints and design ideas, that is, the equation y=g(x) is a known condition.

[0059] The only thing left is Two unknown quantities. In the above formula, when point B coincides with point C, that is, under the boundary conditions of the curve, formula (1) only has A variable that can be solved to get When point B is any point other than point C, u is the independent variable. As the dependent variable, we can get Function about u. Due to the corresponding relationship between point B and point D, the coordinate relationship of the two points can be obtained as follows, that is, the functional relationship between any point on the combustion curve and the intersection point on the elimination curve:

[0060]

[0061] like Figure 6 As shown, based on the functional relationship between the combustion circumference and the combustion meat thickness, according to the functional relationship between any point on the combustion curve and the intersection point and the inclination angle of the elimination curve, the inclination angle and coordinates of the end point of the combustion curve are obtained; based on the functional relationship between any point on the combustion curve and the intersection point, according to the coordinates of the intersection point, the inclination angle and coordinates of any point on the combustion curve are obtained; all the combustion curve points are output, and the equation of the combustion curve is obtained through fitting processing.

[0062] As a specific embodiment, before outputting all the combustion curve points, the method further includes: when the combustion thickness is zero, obtaining the coordinates of the starting point of the elimination curve, and comparing the coordinates of the starting point of the elimination curve and the coordinates of the end point of the combustion curve with the combustion boundary conditions; when the combustion boundary conditions are not met, continuing to iterate the combustion curve points based on the functional relationship between the combustion circumference and the combustion thickness until the combustion boundary conditions are met, and outputting all the combustion curve points.

[0063] It should be noted that when the elimination curve and the combustion curve have no intersection at the initial moment, it means that the minimum u is not 0. In numerical calculation, the following flow chart is used for calculation: After outputting a series of combustion curve points, the combustion curve can be obtained using data processing software, and an approximate curve can be obtained by fitting. In theory, an accurate combustion curve can be obtained by analytical calculation using formula (1), but in numerical calculation, since the calculation step length △u cannot be infinitely small, only an approximate curve can be obtained. In any case, the curve obtained by this method can have a high degree of accuracy with the target curve at any time, which is higher than the accuracy of traditional methods.

[0064] Based on the equation of the combustion curve, the process of carrying out engine charge design includes: checking according to the obtained combustion surface curve, calculating the combustion area-combustion thickness curve, and then obtaining the thrust-time curve and pressure-time curve. Based on this, the charge structure integrity calculation and insulation structure adjustment are carried out. If the thrust curve reaches the expected deviation range and the structural integrity calculation passes, the design is considered complete, otherwise the boundary conditions are adjusted or the curve equation is eliminated.

[0065] The implementation method of the present invention is a "reverse design" method, that is, the required thrust-time curve is converted into the combustion surface-thickness curve required by the charge design profession, that is, the curve of the combustion area as the combustion surface moves toward its normal distance, and then the charge structure is derived by determining the geometric structure and calculation formula. This method reduces the number of iterations and the reliance on experience, and is a brand-new design idea and method.

[0066] The present invention does not require the selection of drug form and structural parameters, thus avoiding a large number of repetitions by inexperienced personnel and reducing the reliance on experience with drug form;

[0067] After analyzing the requirements, the present invention can obtain a structure that meets the requirements through a calculation formula, and the structure can well meet the requirements. Because the requirements are unique and certain, there is no need to perform trial calculations like forward design, so no iteration or very few iterations are required, thereby reducing the number of iterations and saving calculation time.

[0068] At the beginning of the design, the present invention only limits the main category of the charging form to two-dimensional charging. It is not necessary to be restricted by the existing drug forms, and new drug forms may be produced. The design results have a wide range.

[0069] Since the present invention performs microelement analysis on each time point of the thrust-time curve, good consistency can be maintained in each period of time, so that the designed drug form has high consistency with the demand.

[0070] The present invention frees the engine performance proposers from constraints, reduces concerns about feasibility, and allows more consideration of better performance.

[0071] The present invention also provides an electronic device, comprising: a memory and a processor; the memory is used to store a program; the processor is used to execute the program to implement each step of the solid motor two-dimensional charge reverse design method.

[0072] The present invention also provides a readable storage medium on which a computer program is stored. When the computer program is executed by a processor, each step of the reverse design method of a two-dimensional charge of a solid motor is implemented.

[0073] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for reverse design of two-dimensional charge of solid rocket motor, characterized in that: The following steps are involved: Cutting off the cross section of each inner hole channel of the two-dimensional charge, and obtaining the combustion curve and the elimination curve on the cross section; Obtain the functional relationship between the burning circumference and the burning meat thickness; Selecting any point on the combustion curve, and moving the point along the normal direction to the elimination curve to obtain an intersection with the elimination curve; Obtaining a functional relationship between any point on the combustion curve and the intersection point; Based on the functional relationship between the combustion circumference and the combustion meat thickness, according to the functional relationship between any point on the combustion curve and the intersection point and the inclination angle of the elimination curve, the inclination angle and coordinates of the end point of the combustion curve are obtained; Based on the functional relationship between any point on the combustion curve and the intersection point, the inclination angle and coordinates of the corresponding point on the combustion curve are obtained according to the coordinates of the intersection point; Outputting all combustion curve points, and obtaining the equation of the combustion curve through fitting processing; Based on the equation of the combustion curve, the engine charge design is carried out.

2. The method for reverse design of two-dimensional charge of solid rocket motor according to claim 1, characterized in that: Before acquiring the combustion curve and the elimination curve on the cross section, the method further includes: establishing a coordinate system on the cross section.

3. The method for reverse design of two-dimensional charge of solid rocket motor according to claim 1, characterized in that: The elimination curve is the symmetry axis of the charge structure, or is the flame retardant wall surface of the charge structure.

4. The method for reverse design of two-dimensional charge of solid rocket motor according to claim 1, characterized in that: The functional relationship between the burning circumference and the burning meat thickness is as follows: Among them, S b is the burning circumference, u is the burning meat thickness, is the inclination angle of the tangent at any point on the combustion curve, is the inclination angle of the end point of the combustion curve, is the inclination angle of the intersection point on the elimination curve.

5. The method for reverse design of two-dimensional charge of solid rocket motor according to claim 4, characterized in that: The functional relationship between any point on the combustion curve and the intersection point is as follows: Among them, g(x) is the elimination curve equation, f(x) is the combustion curve equation, and x D is the horizontal coordinate of the intersection point on the elimination curve.

6. The method for reverse design of two-dimensional charge of solid rocket motor according to claim 1, characterized in that: Before outputting all the combustion curve points, the method also includes: when the combustion thickness is zero, obtaining the coordinates of the starting point of the elimination curve, and comparing the coordinates of the starting point of the elimination curve and the coordinates of the end point of the combustion curve with the combustion boundary conditions; when the combustion boundary conditions are not met, continuing to iterate the combustion curve points based on the functional relationship between the combustion circumference and the combustion thickness until the combustion boundary conditions are met, and outputting all the combustion curve points.

7. The method for reverse designing two-dimensional charge of solid rocket motor according to claim 1, characterized in that: Based on the equation of the combustion curve, the process of carrying out engine charge design includes: based on the equation of the combustion curve, obtaining the combustion circumference of the combustion curve, and obtaining the combustion area based on the product of the combustion circumference and the charge length; based on the functional relationship between the combustion circumference and the combustion thickness, obtaining the functional relationship between the combustion area and the combustion thickness; based on the functional relationship between the combustion area and the combustion thickness, obtaining the thrust-time curve and the pressure-time curve, and carrying out engine charge design based on the thrust-time curve and the pressure-time curve.

8. An electronic device, characterized in that: include: Memory and processor; The memory is used to store programs; The processor is used to execute the program to implement each step of the solid rocket two-dimensional charge reverse design method as described in any one of claims 1-7.

9. A readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, each step of the method for reverse design of two-dimensional charge of a solid rocket motor as described in any one of claims 1 to 7 is implemented.

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