Accelerated aging test method for checking reverse opening life of interlayer of double-pulse engine

Abstract

The invention relates to an accelerated aging test method for checking the reverse opening life of a double-pulse engine interlayer, which comprises the following steps: carrying out a thermal accelerated aging test on an interlayer material to obtain an aging model of the interlayer material; calculating an acceleration coefficient r at the aging temperature Ta relative to the working temperature Ts; according to the estimated service life and the acceleration coefficient r, the acceleration time ta of the interlayer at the aging temperature Ta is calculated; carrying out a thermal accelerated aging test on the interlayer; according to the required interlayer opening moment, the thickness of the double-pulse real explosive is calculated, and production, matching and final assembly of the double-pulse engine interlayer reverse opening test engine are completed; and carrying out double-pulse engine interlayer reverse opening test engine ground test run, and determining whether the interlayer can meet the reverse opening service life requirement or not according to the test run result. The method provided by the invention can efficiently, quickly and intuitively examine the reverse opening life of the interlayer.

Description

TECHNICAL FIELD

[0001] The application relates to an accelerated aging test method for examining reverse opening life of a double-pulse engine partition, and belongs to the field of double-pulse solid engines. BACKGROUND

[0002] The axial-radial partition type double-pulse solid rocket engine mainly comprises a pulse propellant column, a pulse ignition device, an axial-radial partition, a double-pulse propellant column, a double-pulse ignition device and a nozzle.

[0003] The working principle of the axial-radial partition type double-pulse solid rocket engine is as follows: after receiving an ignition instruction, the engine starts a pulse, and the pulse fuel is exhausted to shut down the engine; during the working period of the pulse combustion chamber, the axial-radial partition must be kept structurally complete; after a certain number of seconds, the double pulse is randomly started through program control, the gas generated by the ignition of the double pulse reversely opens the axial-radial partition, and the double-pulse fuel is exhausted to shut down the engine again. The material, structure form and working mode of the double-pulse engine pulse propellant column and double-pulse propellant column are basically the same as those of a conventional engine, and the service life of the double-pulse engine may be similar to that of the conventional engine.

[0004] However, whether the partition can be normally opened in the designed manner after long-term storage is directly related to whether the double-pulse engine can normally work, especially in the first few seconds of the initial working of the double-pulse combustion chamber. If the axial-radial partition is not opened in the designed manner, too many fragments of the opened axial-radial partition may be generated, which may cause nozzle blockage, result in excessively high pressure in the engine, and further result in explosion. Therefore, the reverse opening performance of the partition after aging needs to be examined. If the reverse opening performance of the partition is examined through natural storage, there are problems of too long test period and high development cost. Therefore, the reverse opening life of the partition needs to be evaluated through the accelerated aging method, which can greatly shorten the test period and development cost.

[0005] Through novelty search, no close related public reports on the accelerated aging test method for examining reverse opening life of a double-pulse engine partition are found in domestic and foreign literatures. SUMMARY

[0006] The technical problem solved by the application is that, aiming at the reverse opening performance problem of the axial-radial partition type double-pulse solid rocket engine partition, an accelerated aging test method for examining reverse opening life of a double-pulse engine partition is provided, and the reverse opening life of the partition can be efficiently, quickly and directly examined.

[0007] The technical solution of the application is as follows:

[0008] The accelerated aging test method for examining reverse opening life of a double-pulse engine partition comprises the following steps:

[0009] A thermal accelerated aging test is carried out on the barrier material to obtain an aging model of the barrier material;

[0010] An accelerated coefficient r of the barrier material at an aging temperature T a relative to a working temperature T s is calculated;

[0011] According to the estimated service life and the accelerated coefficient r, an accelerated time t a of the barrier at the aging temperature T a is calculated;

[0012] A thermal accelerated aging test is carried out on the barrier;

[0013] According to a required opening time of the barrier, the thickness of the two-pulse true propellant is calculated, and the production, matching and assembly of the barrier reverse opening test engine of the two-pulse engine are completed;

[0014] The ground test of the barrier reverse opening test engine of the two-pulse engine is carried out, and whether the barrier can meet the reverse opening service life requirement is determined according to the test result.

[0015] Further, the thermal accelerated aging test is carried out on the barrier material to obtain an aging model of the barrier material, specifically:

[0016] According to the accelerated test of the barrier material, the aging model of the sensitive parameter of the barrier material conforms to the following formula, and the sensitive parameter is elongation;

[0017] K=Ze -E / RT

[0018] In the formula, K is an aging speed constant, Z is a pre-exponential factor, E is an aging activation energy, R is a molar gas constant, and T is an aging temperature.

[0019] Further, the accelerated coefficient at the aging temperature relative to the working temperature is calculated, specifically:

[0020] The typical working temperature T s of the engine is determined, and the aging speed constant K s of the barrier material at the aging temperature T s is determined according to the formula

[0021] In the case of guaranteeing time, the aging temperature T a is selected, and the aging speed constant K a of the barrier material at the aging temperature T a is determined according to the formula

[0022] The relative working temperature T s of the barrier material at the aging temperature T a is determined.The acceleration coefficient r of the insulation layer is formula

[0023]

[0024] Further, the acceleration time of the insulation layer at the aging temperature is calculated according to the estimated life and the acceleration coefficient r, and specifically is:

[0025] Supposing that the estimated life of the engine is t years, the life of the insulation layer should be not less than t years, then the acceleration time t of the insulation layer at the aging temperature T a a is formula

[0026] Further, the thermal acceleration aging test of the insulation layer is carried out, and specifically is: the insulation layer is placed in a high-temperature incubator for t a years, the temperature of the incubator is set to T a , after the thermal acceleration aging test of the insulation layer is completed, the insulation layer is taken out.

[0027] Further, according to the required opening time of the insulation layer, the thickness of the two-pulse true propellant is calculated, and the production, matching and general assembly of the insulation layer reverse opening test engine of the two-pulse engine are completed, and specifically are:

[0028] According to the opening time s of the insulation layer and the burning rate r of the two-pulse true propellant, the thickness L value of the two-pulse true propellant is determined, L=sxr;

[0029] According to the inner diameter of the combustion chamber and the thickness L value of the two-pulse true propellant, the thickness of the two-pulse false propellant is determined; the thickness of the two-pulse false propellant=inner diameter of the combustion chamber-L;

[0030] After the test container is respectively bonded with the heat insulation layer and the sponge layer according to the design condition, the two-pulse false propellant is first installed in the combustion chamber according to the calculated thickness value of the false propellant;

[0031] After the two-pulse false propellant is solidified, the two-pulse true propellant is installed according to the L value, and after the two-pulse true propellant is solidified, the production, matching of the components of the insulation layer reverse opening test engine of the two-pulse engine are completed, and the general assembly of the insulation layer reverse opening test engine of the two-pulse engine is completed.

[0032] Further, the ground test of the insulation layer reverse opening test engine of the two-pulse engine is carried out, and according to the test results, whether the insulation layer can meet the reverse opening life requirement is determined, and specifically is:

[0033] ​The engine ground test is carried out by carrying out the reverse opening test of the barrier layer. During the test, the two-pulse ignition device works, high-temperature and high-pressure gas jets are sprayed out, the two-pulse true propellant is ignited, and the two-pulse true propellant is completely burned until the two-pulse true propellant is completely burned; the cavity pressures before and after the opening of the barrier layer after the ignition of the two-pulse true propellant are measured through the pressure measuring hole of the one-pulse ignition top cover, the pressure of the two-pulse true propellant cavity is measured through the through hole of the two-pulse ignition device, the actual opening time of the barrier layer is obtained according to the cavity pressure change measured at the one-pulse pressure measuring hole, and whether the actual opening time of the barrier layer after aging meets the requirements is judged.

[0034] If the actual opening time T of the barrier layer 实际打开 If the following conditions are met, it is considered that the actual opening time of the barrier layer after aging meets the requirements:

[0035] T 设计打开 -0.2<T 实际打开 <T 设计打开 +0.2

[0036] Wherein, T 设计打开 represents the opening time of the barrier layer design.

[0037] Further, after the engine ground test, the nozzle is detached from the test device, whether the barrier layer opens normally after aging according to the established mode is judged according to the state of the barrier layer after the test, and whether the barrier layer has large fragments is checked.

[0038] Further, the large fragments refer to fragments with a size not less than the inner diameter of the throat of the nozzle.

[0039] The beneficial effects of the present application compared with the prior art are:

[0040] (1) The test method can greatly shorten the natural storage time of the barrier layer through the thermal accelerated aging method.

[0041] (2) The test engine used in the test method can directly use the I and II pulse ignition devices of the full-size engine, and after the test is completed, a new standard gas generator and ignition device are installed to perform the test again, thereby greatly reducing the development cycle and cost. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 It is a schematic diagram of the test device for different opening times of the barrier layer.

[0043] Among them, 1 is a one-pulse ignition top cover, 2 is a two-pulse ignition device, 3 is a test container, 4 is an insulation layer, 5 is a sponge layer, 6 is a two-pulse false propellant, 7 is a two-pulse true propellant, 9 is a transition section, and 10 is a nozzle. DETAILED DESCRIPTION

[0044] The specific embodiments of the present application will be further described in detail below with reference to the drawings.

[0045] In order to carry out the accelerated aging test of the reverse opening life of the double pulse engine barrier, the present application uses the barrier different opening time test device as shown in Figure 1 The device includes a pulse ignition top cover 1, a two-pulse ignition device 2, a test container 3, a thermal insulation layer 4, a sponge layer 5, a two-pulse false propellant 6, a two-pulse true propellant 7, a barrier 8, a transition section 9 and a nozzle 10.

[0046] The inner wall of the test container 3 is sequentially bonded with the thermal insulation layer 4 and the sponge layer 5, which is used to simulate the deformation of the composite shell under the action of internal pressure. The sponge layer 5 is the two-pulse false propellant 6, which is used to simulate the support of the two-pulse propellant column of the full-size engine on the barrier and control the thickness of the two-pulse true propellant 7. The cavity of the two-pulse false propellant 6 is the two-pulse true propellant 7, which provides energy for viewing the barrier opening at different times. The right end face of the two-pulse false propellant 6 and the two-pulse true propellant 7 and the inner hole surface columnar hollow structure of the two-pulse true propellant 7 are bonded with the barrier 8; one end of the transition section 9 is fixed on the test container 3 by bolts, and the barrier is pressed tightly, and the other end of the transition section 9 is fixedly connected with the nozzle 10. The two-pulse ignition device 2 is fixed at the bottom left end of the test container 3, and the two-pulse ignition device 2 is provided with two through holes, one of which is communicated with the two-pulse true propellant 7 for igniting the two-pulse true propellant 7, and the other is used for measuring the pressure of the two-pulse true propellant cavity. The pulse ignition top cover 1 is installed on the two-pulse ignition device 2, and the pulse ignition top cover 1 is provided with a pressure measuring hole, which is communicated with the cavity formed in the columnar hollow structure of the two-pulse true propellant 7.

[0047] The material of the test container 3 is 30CrMnSiA steel. The test device 1:1 simulates the composite shell, two-pulse charge, propellant column and barrier in the engine.

[0048] The accelerated aging test method for evaluating the reverse opening life of the double pulse engine barrier provided by the present application includes the following processes: thermal accelerated aging test is carried out on the barrier material to obtain the aging model of the barrier material, and then the acceleration coefficient at the aging temperature relative to the working temperature is calculated. According to the estimated life and the acceleration coefficient, the acceleration time of the barrier at the aging temperature is calculated. The thermal accelerated aging test is carried out on the barrier, the thickness of the two-pulse true propellant is calculated according to the required barrier opening time, the double pulse engine barrier reverse opening test engine production, matching and assembly are completed. The double pulse engine barrier reverse opening test engine is tested on the ground, and according to the test results, it is determined whether the barrier can meet the reverse opening life requirement.

[0049] The specific implementation is as follows:

[0050] (1) Thermal accelerated aging test of barrier material

[0051] The interlayers of dual-pulse solid rocket motors are typically made of rubber. Research on related materials, both domestically and internationally, indicates that their aging properties conform to the Arrhenius equation. Accelerated aging testing of interlayer materials can be conducted in accordance with the methods outlined in GJB10021-2021, "Accelerated Aging Test Methods for Composite Solid Propellants," or GB / T3512-2001, "Hot Air Accelerated Aging and Heat Resistance Tests for Vulcanized Rubber or Thermoplastic Rubber."

[0052] According to the accelerated test of the interlayer material, the aging model of the sensitive parameter of the isolation material can be obtained to conform to the formula (1). Usually, the sensitive parameter of the isolation material is the elongation.

[0053] K=Ze -E / RT (1)

[0054] Where:

[0055] K——aging rate constant;

[0056] Z——pre-exponential factor;

[0057] E——Aging activation energy J / mol;

[0058] R——molar gas constant J / (K·mol);

[0059] T——aging temperature K;

[0060] Typical operating temperature of the engine T s , then the interlayer material is T s Lower aging rate constant K s Formula (2)

[0061]

[0062] Generally speaking, the lower the temperature, the closer it is to the natural aging mechanism. Therefore, in order to ensure the time, the aging temperature T is selected. a , then the interlayer material is T a Lower aging rate constant K a Formula (3)

[0063]

[0064] The interlayer material is at the aging temperature T a Lower relative operating temperature T s The acceleration coefficient r is formula (4)

[0065]

[0066] (2) Calculate the interlayer acceleration time

[0067] The life of the engine is estimated to be t years, so the life of the interlayer should be no less than t years, so the accelerated time t of the interlayer at the aging temperature T a is formula (5) a

[0068]

[0069] (3) Place the interlayer in a high-temperature incubator for t a , set the incubator temperature to T a , and after completing the thermal accelerated aging test of the interlayer, take it out.

[0070] (4) Determine the thickness L value of the two-pulse true propellant according to the time s when the interlayer is opened and the burning rate r of the two-pulse true propellant; determine the thickness of the two-pulse false propellant according to the inner diameter of the combustion chamber and the thickness L value of the two-pulse true propellant; after the adiabatic layer and the sponge layer are bonded according to the design, install the two-pulse false propellant in the combustion chamber according to the calculated thickness value.

[0071] The thickness L of the two-pulse true propellant is s x r;

[0072] The thickness of the two-pulse false propellant is the inner diameter of the combustion chamber minus the thickness L of the two-pulse true propellant.

[0073] After the two-pulse false propellant is cured, install the two-pulse true propellant, and after the two-pulse true propellant is cured, complete the production, matching of other components of the interlayer reverse opening test engine, and complete the general assembly of the interlayer reverse opening test engine according to the figure. Figure 1

[0074] (5) Carry out ground test of the interlayer reverse opening test engine, during the test, the two-pulse ignition device 2 works, sprays high-temperature and high-pressure gas jet, ignites the two-pulse true propellant 7, until the two-pulse true propellant 7 is completely burned; measure the cavity pressure before and after the opening of the interlayer 8 after the ignition of the two-pulse true propellant through the pressure measuring hole of the one-pulse ignition top cover 1, measure the pressure of the two-pulse true propellant cavity through the through hole on the two-pulse ignition device, according to the change of the cavity pressure measured at the one-pulse pressure measuring hole, obtain the actual opening time of the interlayer, and judge whether the actual opening time of the interlayer after aging meets the requirements.

[0075] If the actual opening time T 实际打开 of the interlayer meets the following conditions, it is considered that the actual opening time of the interlayer after aging meets the requirements:

[0076] T 设计打开 -0.2 < T 实际打开 < T 设计打开 +0.2

[0077] Where T 设计打开 represents the opening time of the interlayer design. ​​

[0078] (6) After the test is completed, the nozzle is detached from the test device, and whether the barrier opens normally according to the predetermined mode after the barrier is aged is judged according to the state of the barrier after the test, and whether the barrier has large fragments is checked. The large fragments refer to fragments with a size not less than the inner diameter of the throat of the nozzle.

[0079] The parts of the present application not described in detail are common knowledge to those skilled in the art.

Claims

1. An accelerated aging test method for evaluating the reverse opening life of a dual-pulse engine barrier, characterized in that include: Conduct thermal accelerated aging tests on interlayer materials to obtain an aging model of the interlayer materials; Calculate the aging temperature T a Relative to the operating temperature T s The acceleration coefficient r; According to the estimated life and acceleration factor r, the interlayer is calculated at the aging temperature T a Acceleration time t a ; Conducting thermal accelerated aging test on the interlayer; Calculate the thickness of the dual-pulse propellant based on the required compartment opening moment, and complete the production, matching, and assembly of the dual-pulse engine compartment reverse opening test engine; Conduct a dual-pulse engine partition reverse opening test and engine ground test. Based on the test results, determine whether the partition can meet the reverse opening life requirements.

2. The accelerated aging test method for evaluating the reverse opening life of a dual-pulse engine partition according to claim 1, characterized in that: The thermal accelerated aging test is carried out on the interlayer material to obtain an aging model of the interlayer material, specifically: According to the accelerated test of the insulation material, the aging model of the sensitive parameters of the insulation material is obtained in accordance with the following formula, where the sensitive parameter is the elongation; K=From -E / RT Where: K is the aging rate constant; Z is the pre-exponential factor; E is the aging activation energy; R is the molar gas constant; T is the aging temperature.

3. The accelerated aging test method for evaluating the reverse opening life of a dual-pulse engine partition according to claim 2, characterized in that: The acceleration factor calculated at the aging temperature relative to the operating temperature is specifically: Typical operating temperature of the engine T s , then the interlayer material is T s Lower aging rate constant K s Formula K s =Ze -E / RTs ; Under the condition of guaranteeing time, select aging temperature T a , then the interlayer material is T a Lower aging rate constant K a For the formula The interlayer material is at the aging temperature T a Lower relative operating temperature T s The acceleration coefficient r is the formula 4. The accelerated aging test method for evaluating the reverse opening life of a dual-pulse engine partition according to claim 1, characterized in that: According to the estimated lifespan and acceleration factor r, the acceleration time of the interlayer at the aging temperature is calculated as follows: Assuming that the estimated life of the engine is t years, the life of the interlayer should be no less than t years, then the interlayer will be a Acceleration time t a For the formula 5. The accelerated aging test method for evaluating the reverse opening life of a dual-pulse engine partition according to claim 1, characterized in that: The thermal accelerated aging test is carried out on the interlayer, specifically: the interlayer is placed in a high temperature insulation box for a , the temperature of the incubator is set to T a After completing the interlayer thermal accelerated aging test, take out the interlayer.

6. The accelerated aging test method for evaluating the reverse opening life of a dual-pulse engine partition according to claim 1, characterized in that: According to the required compartment opening time, calculate the thickness of the dual-pulse real propellant, and complete the production, matching and assembly of the dual-pulse engine compartment reverse opening test engine. Specifically: According to the time s when the barrier is opened and the burning rate r of the two-pulse propellant, the thickness L of the two-pulse propellant is determined, L = s × r; Determine the thickness of the two-pulse fake drug based on the inner diameter of the combustion chamber and the thickness L of the two-pulse genuine drug; the thickness of the two-pulse fake drug = the inner diameter of the combustion chamber - L; After the insulation layer and sponge layer of the test container are bonded according to the design, the two-pulse dummy is installed in the combustion chamber according to the calculated dummy thickness. After the two-pulse fake medicine is solidified, the two-pulse real medicine is installed according to the L value. After the two-pulse real medicine is solidified, the production and matching of the parts and components of the partition reverse opening test engine are completed, and the final assembly of the partition reverse opening test engine is completed.

7. The accelerated aging test method for evaluating the reverse opening life of a dual-pulse engine partition according to claim 1, characterized in that: The dual-pulse engine barrier reverse opening test engine ground test is carried out to determine whether the barrier can meet the reverse opening life requirements based on the test results, specifically: Conducting a ground test of the engine with the compartment reverse opening test. During the test, the two-pulse ignition device operates, ejecting a high-temperature and high-pressure gas jet to ignite the two-pulse propellant until the two-pulse propellant is completely burned; The cavity pressure before and after the barrier is opened after the second pulse propellant is ignited is measured through the pressure measuring hole on the top cover of the first pulse ignition device. The pressure of the second pulse propellant cavity is measured through the through hole on the second pulse ignition device. The actual opening time of the barrier is obtained based on the change in the cavity pressure measured at the first pulse pressure measuring hole. It is then judged whether the actual opening time of the barrier after aging meets the requirements. If the actual opening time of the partition is T 实际打开 If the following conditions are met, the actual opening time of the interlayer after aging is considered to meet the requirements: T 设计打开 -0.2<T 实际打开 <T 设计打开 +0.2 Among them, T 设计打开 Indicates the moment when the compartment design is opened.

8. The accelerated aging test method for evaluating the reverse opening life of a dual-pulse engine partition according to claim 1, characterized in that: After the engine ground test, the nozzle is removed from the test device. The status of the partition after the test is used to determine whether the partition opens normally in the established manner after aging, and to check whether there are any large fragments in the partition.

9. The accelerated aging test method for evaluating the reverse opening life of a dual-pulse engine partition according to claim 8, characterized in that: Larger fragments are fragments whose size is not smaller than the inner diameter of the nozzle throat.

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