Large-caliber engine heat insulation reinforcing method and structure meeting overload ablation

Abstract

The invention provides a large-diameter engine heat insulation reinforcing method and structure meeting overload ablation, and mainly solves the problem that a heat insulation layer design method and structure of a traditional large-diameter solid rocket are difficult to meet local heat insulation design of an active section of an aircraft. According to the scheme, the reinforcing area is determined through numerical simulation of the two-phase flow of the flow field in the engine, the ablation rate and the ablation time are obtained in combination with the ablation test, the reinforcing thickness of the reinforcing area is obtained, and therefore fine design of the engine combustion chamber heat insulation profile is completed, and the working safety of the engine is improved. According to the reinforcing structure designed by the invention, the size thickness precision is high, the process is simple, the quality consistency is good, and the high-reliability design of the large-caliber solid rocket engine heat insulation structure capable of resisting long-time fixed overload ablation of the active section is realized.

Description

Technical Field

[0001] The invention belongs to the field of solid rocket engines, and in particular relates to a method and structure for thermal insulation reinforcement of a large-caliber engine that meets the requirements of overload ablation. Background Art

[0002] Large-caliber solid rocket engines are composed of an ignition system, a combustion chamber, a charge, a nozzle and other parts. Among them, the combustion chamber is part of the load-bearing structure of the entire system, and is a cavity for storing charge and burning propellant, and has the ability to withstand high temperature and high pressure. During the operation of the solid rocket engine, the temperature of the combustion chamber reaches above 3000K, and the combustion chamber also needs to withstand the scouring of high-temperature, high-pressure combustion gas and condensed phase particles. During the active phase of the flight maneuver of the aircraft, the local area of ​​the combustion chamber is particularly significantly scoured by the combustion gas and condensed phase particles. In order to avoid damage and instability to the combustion chamber shell, it is necessary to set an insulation layer structure on the inner surface of the combustion chamber shell, and thicken and reinforce the insulation layer at the significant scouring location. At present, the insulation layer structure design of large-caliber solid rockets generally designs the thickness of each section of the insulation layer of the combustion chamber based on the time that each section of the combustion chamber contacts the combustion gas and condensed phase particles; however, there is a lack of understanding of the adverse effects of overload ablation on the combustion chamber of the solid rocket engine caused by the active stage flight maneuvers of the aircraft; under overload conditions, there is a lack of systematic design guidance on the influence and change law of the ablation rate of the insulation material; and there is also insufficient understanding of the scope and degree of the influence of reciprocating roll on the local area of ​​the engine combustion chamber shell. Inadequate design of the insulation layer structure in the corresponding part may cause the combustion chamber shell to burn through, thereby causing the engine to disintegrate. Therefore, the insulation layer design method and structure of the traditional large-caliber solid rocket are difficult to meet the insulation requirements of the active stage flight maneuvers of the aircraft. The insulation layer structure design urgently needs to consider the influence of local overload ablation on the insulation structure and carry out insulation reinforcement structure design. Summary of the invention

[0003] In order to overcome the shortcomings of the existing technology and to solve the problem that the insulation design method and structure of traditional large-caliber solid rockets are difficult to meet the local insulation design of the active section of the aircraft, a large-caliber engine insulation reinforcement method and structure that meets overload ablation are proposed, which breaks through the conventional large-caliber solid rocket engine insulation layer design means and realizes the refined design of the insulation surface.

[0004] The method for thermal insulation reinforcement of a large-caliber engine that meets overload ablation requirements comprises the following steps:

[0005] Step 1: Use Standard The turbulence model is used to perform numerical simulation of the two-phase flow field inside the engine;

[0006] The input parameters for the numerical simulation of two-phase flow in the engine flow field include overload, roll, flow rate and particle size;

[0007] Step 2: Determine the scope of the reinforcement area;

[0008] The steps of determining the scope of the reinforcement area are: obtaining the particle concentration distribution according to the two-phase flow numerical simulation of the flow field in the engine, and calculating the average particle concentration;

[0009] The reinforcement area range is: the area where the particle concentration distribution is 20% higher than the average particle concentration;

[0010] Step 3: Determine the thickness of the reinforced structural insulation material;

[0011] Step 4: Design reinforcement structure;

[0012] The reinforcement structure is designed according to the scope of the reinforcement area and the thickness of the insulation material of the reinforcement structure.

[0013] Furthermore, in step three, the step of determining the thickness of the reinforced structural insulation material is:

[0014] According to the numerical simulation results of the two-phase flow field in the engine, the engine was simulated by overload ablation and an ablation test was carried out. The ablation rate of the reinforced structure insulation material was obtained based on the ablation test. The thickness of the reinforced structure insulation material is the product of the ablation rate of the reinforced structure and the ablation time.

[0015] Furthermore, a structure designed based on a method for thermal insulation reinforcement of a large-caliber engine that meets overload ablation requirements includes an engine combustion chamber and a thermal insulation reinforcement structure; the rear barrel section of the engine combustion chamber is a hollow cylinder; the thermal insulation reinforcement structure is arranged on the inner surface of the engine combustion chamber; the thermal insulation reinforcement structure is a hollow cylinder; the axis of the thermal insulation reinforcement structure is collinear with the axis of the engine combustion chamber; the inner surface of the thermal insulation reinforcement structure is nested with a first boss, a second boss and a third boss in sequence; the first boss, the second boss and the third boss are all hollow cylinders; the second boss is arranged on the inner surface of the first boss; the third boss is arranged on the inner surface of the second boss; the height of the first boss is greater than the height of the second boss; the height of the second boss is greater than the height of the third boss; the bottom surfaces of the first boss, the second boss and the third boss are the surfaces closest to the rear skirt of the engine combustion chamber; the bottom surfaces of the first boss, the second boss and the third boss are coplanar; the central angle of the cross section of the thermal insulation reinforcement structure is The outer surface of the thermal insulation reinforcement structure covers the significant ablation area formed by the fixed overload and the reciprocating rolling of the active section, that is, the reinforcement area.

[0016] Furthermore, the The value is 90 degrees.

[0017] Furthermore, the material of the thermal insulation reinforcement structure is EPDM rubber.

[0018] Furthermore, the radial thickness of the first boss is 8 mm.

[0019] Furthermore, the radial thickness of the second boss is 6 mm.

[0020] Furthermore, the radial thickness of the third boss is 4 mm.

[0021] The beneficial effects of the present invention are as follows: compared with the prior art, the present invention increases the insulation thickness of the reinforced structure area, and the insulation thickness is increased by at least 1 times, which can improve the anti-ablation performance and thermal insulation performance of the combustion chamber of a large-caliber solid rocket engine, and ensure that under the conditions of constant overload ablation and reciprocating rolling of the active section, the combustion chamber shell is not severely ablated by high-temperature combustion gas and condensed phase particles, thereby improving the safety of engine operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the thermal insulation reinforcement structure of the engine combustion chamber according to an embodiment of the present invention;

[0023] Figure 2 It is a partial enlarged view of the thermal insulation reinforcement structure of the engine combustion chamber according to an embodiment of the present invention;

[0024] Figure 3 1. It is a left view of the thermal insulation reinforcement structure of the engine combustion chamber according to an embodiment of the present invention;

[0025] Figure 4 2. It is a bottom view of the thermal insulation reinforcement structure of the engine combustion chamber according to an embodiment of the present invention;

[0026] Among them: 1 - insulation reinforcement structure; 2 - third boss; 3 - second boss; 4 - first boss. DETAILED DESCRIPTION

[0027] A method and structure for thermal insulation reinforcement of a large-caliber engine that meets overload ablation requirements includes the following steps:

[0028] Step 1: Use Standard The turbulence model is used to perform numerical simulation of the two-phase flow field inside the engine;

[0029] The input parameters for the numerical simulation of two-phase flow in the engine flow field include overload, roll, flow rate and particle size;

[0030] Step 2: Determine the scope of the reinforcement area;

[0031] The steps to determine the scope of the reinforcement area are:

[0032] The particle concentration distribution is obtained based on the two-phase flow numerical simulation in the engine flow field, and the average particle concentration is calculated;

[0033] The reinforcement area range is: the area where the particle concentration distribution is 20% higher than the average particle concentration;

[0034] Step 3: Determine the thickness of the reinforced structural insulation material;

[0035] According to the numerical simulation results of the two-phase flow field in the engine, the engine is simulated by overload ablation and an ablation test is carried out. The ablation rate of the reinforcement structure is obtained according to the ablation test, and the thickness of the insulation material of the reinforcement structure is determined according to the ablation rate and the ablation time of the reinforcement area; the thickness of the insulation material of the reinforcement structure is the product of the ablation rate and the ablation time;

[0036] Step 4: Design reinforcement structure;

[0037] The reinforcement structure is designed according to the scope of the reinforcement area and the thickness of the insulation material of the reinforcement structure.

[0038] A structure designed based on a method for thermal insulation reinforcement of a large-caliber engine that meets overload ablation requirements, comprising an engine combustion chamber and a thermal insulation reinforcement structure; the rear barrel section of the engine combustion chamber is a hollow cylinder; the thermal insulation reinforcement structure is arranged on the inner surface of the engine combustion chamber; the thermal insulation reinforcement structure is a hollow cylinder; the axis of the thermal insulation reinforcement structure is in line with the axis of the engine combustion chamber; a first boss, a second boss and a third boss are nested in sequence on the inner surface of the thermal insulation reinforcement structure; the first boss, the second boss and the third boss are all hollow cylinders; a second boss is arranged on the inner surface of the first boss; a third boss is arranged on the inner surface of the second boss; the height of the first boss is greater than the height of the second boss; the height of the second boss is greater than the height of the third boss; the bottom surfaces of the first boss, the second boss and the third boss are the surfaces closest to the rear skirt of the engine combustion chamber; the bottom surfaces of the first boss, the second boss and the third boss are coplanar; the central angle of the cross section of the thermal insulation reinforcement structure is The outer surface of the thermal insulation reinforcement structure covers the significant ablation area formed by the constant overload and the reciprocating rolling of the active section; The value is 90 degrees; the material of the thermal insulation reinforcement structure is EPDM rubber; the radial thickness of the first boss is 8 mm; the radial thickness of the second boss is 6 mm; the radial thickness of the third boss is 4 mm; the thickness of the boss is based on the results of the two-phase flow numerical simulation of the flow field in the engine, and an ablation test is carried out on an overload ablation simulation engine. The ablation rate of the reinforcement structure is obtained according to the thermal insulation ablation test, and the thickness of the thermal insulation material of the reinforcement structure is determined according to the ablation rate and the ablation time of the reinforcement area. The calculation method of the minimum thickness of the thermal insulation material of the reinforcement structure is the product of the ablation rate and the ablation time.

[0039] Fixed overload refers to a fixed maneuvering overload direction.

[0040] In order to make the purpose, content and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below in conjunction with the drawings and examples.

[0041] The schematic diagram of the thermal insulation reinforcement structure of the engine combustion chamber according to the embodiment of the present invention is as follows Figures 1 to 4 shown.

[0042] The thermal insulation reinforcement structure of the combustion chamber of a large-caliber solid rocket engine is a multi-step structure of a quarter hollow rotating body. The thermal insulation reinforcement structure is made of EPDM rubber material. The reinforcement structure is used for thermal insulation and overload ablation resistance inside the rear barrel section of a large-caliber solid rocket engine.

[0043] The insulation reinforcement structure of the combustion chamber corresponds to the significant ablation area formed by constant overload and reciprocating rolling of the active section. When the engine is working, the propellant column in the rear barrel section of the combustion chamber is burned out, and the corresponding insulation reinforcement structure is exposed to high-temperature and high-pressure combustion gas and condensed phase particles. The thickening of the insulation reinforcement structure can ensure that the insulation layer has safe and reliable thermal protection during the engine's constant overload ablation and reciprocating rolling of the active section, and prevent the combustion chamber shell from being damaged and unstable.

[0044] The axial range of the combustion chamber insulation layer reinforcement structure is between 490mm and 1030mm from the rear skirt end face. The central angle of the insulation reinforcement structure is 90°, which completely covers the significant ablation area caused by constant overload and reciprocating rolling of the active section.

[0045] The thickness of the insulation reinforcement structure of the combustion chamber is 18mm, 14mm, and 8mm from the nearest to the farthest distance from the rear skirt end surface. Compared with the unreinforced area of ​​the same section of the combustion chamber, the thickness of the insulation reinforcement structure has increased by 9mm, 8mm, and 4mm, respectively, ensuring that the insulation layer in this area meets the requirements of fixed overload and reciprocating rolling.

[0046] A design method for a thermal insulation reinforcement structure of a large-caliber solid rocket engine combustion chamber that simultaneously satisfies engine constant overload ablation and active segment reciprocating rolling includes:

[0047] Step 1: Based on the input parameters such as overload, roll, flow rate and particle size, the Standard k-ε turbulence model is used to perform numerical simulation of the two-phase flow field in the engine;

[0048] Step 2: Obtain particle concentration distribution based on two-phase flow numerical simulation of the flow field in the engine, and determine the location range of the reinforcement area based on the high particle concentration area;

[0049] Step 3: Based on the results of the two-phase numerical simulation of the flow field in the engine, an ablation test is performed using an overload ablation simulation engine. The ablation rate of the reinforcement structure is obtained based on the ablation test. The thickness of the insulation material of the reinforcement structure is determined based on the ablation rate and the ablation time of the reinforcement area.

[0050] Step 4: Finally, design the reinforcement structure based on the location range of the reinforcement area and the thickness of the insulation material of the reinforcement structure.

[0051] The thermal insulation reinforcement structure of the present invention is an optimization of the existing solid rocket engine thermal insulation layer design. The thermal insulation reinforcement structure of the combustion chamber of a large-caliber solid rocket engine that satisfies both the engine constant overload ablation and the active section reciprocating rolling is a quarter hollow rotating body multi-step structure. The thermal insulation reinforcement structure is made of EPDM rubber material. The axial range of the thermal insulation reinforcement structure is between 490mm and 1030mm from the rear skirt end face. The central angle of the thermal insulation reinforcement structure is 90°. The thickness of the thermal insulation reinforcement structure is 18mm, 14mm, and 8mm from near to far from the rear skirt end face. The present invention can improve the working safety of the engine without significantly increasing the negative mass of the engine; the negative mass of the engine refers to the mass of the engine excluding the propellant.

Claims

1. A method for thermal insulation reinforcement of a large-caliber engine that meets overload ablation requirements. It is characterized in that The steps include: Step 1: Use Standard The turbulence model is used to perform numerical simulation of the two-phase flow field inside the engine; Step 2: Determine the scope of the reinforcement area; The steps for determining the scope of the reinforcement area are as follows: obtaining the particle concentration distribution through the two-phase flow numerical simulation of the flow field in the engine and calculating the average particle concentration; the scope of the reinforcement area is the area where the particle concentration distribution is 20% higher than the average particle concentration; Step 3: Determine the thickness of the reinforced structural insulation material; Step 4: Design reinforcement structure; The reinforcement structure is designed according to the scope of the reinforcement area and the thickness of the insulation material of the reinforcement structure.

2. A method for thermal insulation reinforcement of a large-caliber engine that meets overload ablation requirements according to claim 1, It is characterized in that The input parameters of the two-phase flow numerical simulation of the flow field in the engine include overload, roll, flow rate and particle size.

3. A method for thermal insulation reinforcement of a large-caliber engine that meets overload ablation requirements according to claim 1, It is characterized in that In the step 3, the step of determining the thickness of the reinforcement structure insulation material is as follows: According to the numerical simulation results of the two-phase flow field in the engine, the engine is simulated by overload ablation and an ablation test is carried out. The ablation rate of the reinforced structural insulation material is obtained based on the ablation test. The thickness of the reinforced structural insulation material is the product of the ablation rate of the reinforced structural insulation material and the ablation time.

4. A structure designed based on the method for thermal insulation reinforcement of a large-caliber engine that meets overload ablation requirements according to claim 1, comprising an engine combustion chamber and a thermal insulation reinforcement structure; the rear barrel section of the engine combustion chamber is a hollow cylinder, Features: The inner surface of the engine combustion chamber is provided with a heat-insulating reinforcement structure; the heat-insulating reinforcement structure is a hollow cylinder; the axis of the heat-insulating reinforcement structure is in line with the axis of the engine combustion chamber; the inner surface of the heat-insulating reinforcement structure is nested with a first boss, a second boss and a third boss in sequence; the first boss, the second boss and the third boss are all hollow cylinders; the inner surface of the first boss is provided with a second boss; the inner surface of the second boss is provided with a third boss; the height of the first boss is greater than the height of the second boss; the height of the second boss is greater than the height of the third boss; the bottom surfaces of the first boss, the second boss and the third boss are the surfaces closest to the rear skirt of the engine combustion chamber; the bottom surfaces of the first boss, the second boss and the third boss are in the same plane; the central angle of the cross section of the heat-insulating reinforcement structure is The outer surface of the thermal insulation reinforcement structure covers the significant ablation area formed by the fixed overload and the reciprocating rolling of the active section, that is, the reinforcement area.

5. The structure designed based on a method for thermal insulation reinforcement of a large-caliber engine that meets overload ablation according to claim 4, Features: Said The value is 90 degrees.

6. The structure designed based on a method for thermal insulation reinforcement of a large-caliber engine that meets overload ablation according to claim 4, Features: The material of the thermal insulation reinforcement structure is EPDM rubber.

7. The structure designed based on a method for thermal insulation reinforcement of a large-caliber engine that meets overload ablation according to claim 4, Features: The radial thickness of the first boss is 8 mm.

8. The structure designed based on a method for thermal insulation reinforcement of a large-caliber engine that meets overload ablation according to claim 4, Features: The radial thickness of the second boss is 6 mm.

9. The structure designed based on a method for thermal insulation reinforcement of a large-caliber engine that meets overload ablation according to claim 4, Features: The radial thickness of the third boss is 4 mm.

Images