Propellant static combustion point fire transfer performance characterization test method

Abstract

The invention relates to the field of propellant tests, and provides a propellant static combustion point ignition performance characterization test method in order to realize propellant static combustion point ignition process performance characterization, and a propellant static combustion test is carried out by adopting different ignition powders and ignition dosages to change propellant ignition conditions. The ignition performance characteristic parameters of the propellant powder point are extracted and analyzed according to the test result, the ignition performance characterization of the propellant powder point is achieved, and the problems that the ignition performance of the propellant powder point cannot be characterized, and the charging design work cannot be guided are solved.

Description

Technical Field

[0001] The invention relates to the field of propellant test and testing, in particular to a propellant static combustion ignition performance characterization test method. Background Art

[0002] Propellant is the energy material in the tube weapon that provides the projectile with flight power. It generates gas pressure by burning in the chamber, and the gas expands to push the projectile to move. Most current propellant charge technical issues use the assumption of "instantaneous full ignition" to approximate the propellant ignition process, and the following problems were found during the propellant performance test.

[0003] (1) The ignition transmission during the internal ballistic process is inconsistent

[0004] In the classical theory of interior ballistics, in order to conveniently express the relationship between the motion of the projectile in the bore and the dynamic combustion performance of the propellant, the basic equation of interior ballistics was established. The equation of interior ballistics is based on the geometric combustion law, that is, the assumption that "all the surfaces of the propellant particles ignite at the same time". During the actual test of static combustion of propellants, it was found that there was an obvious inconsistency in the ignition transmission.

[0005] (2) There are large differences in repeated tests during the initial combustion stage

[0006] During the closed explosive device test, it was found that when repeated tests were carried out with the same propellant charge and the same test conditions, the repeatability of the initial combustion stage of the pressure change curve was poor, which was obviously caused by the lack of thorough research on the propellant ignition problem.

[0007] The main reasons for the above problems are the inconsistent static combustion ignition time of the propellant, the inconsistent ignition intensity of the propellant, the surface ignition delay between the propellant particles (non-instantaneous comprehensive ignition), etc. Summary of the invention

[0008] In order to achieve the performance characterization of the static combustion ignition transfer process of propellant, the present application provides a test method for characterizing the static combustion ignition transfer performance of propellant.

[0009] The technical solution adopted by the present invention to solve the above problems is:

[0010] The test method for characterizing the static combustion ignition performance of propellants includes:

[0011] Prepare test samples and reference samples. The test samples are a test group consisting of the same propellant to be tested, different ignition charges and different filling densities. The reference samples and test samples are samples from different batches of the propellant scientific research and production process or samples before and after scientific research optimization iterations.

[0012] Use a closed explosive to load the test sample and reference sample respectively and carry out static combustion ignition performance test, and collect the pressure-time curve;

[0013] The pressure-time curve is processed and calculated to obtain the static combustion ignition characteristic parameters corresponding to different ignition charges and different ignition charge amounts of the test sample and the reference sample: ignition pressure P ig , Fire burning time T cj , fire transmission intensity Γ cj , the maximum pressure generated by the combustion of propellant P m ;

[0014] Based on the ignition pressure ratio ε, the ignition combustion time T cj and fire intensity Γ cj The ignition performance function relationship between the test sample and the reference sample is established respectively, where the ignition pressure accounts for

[0015] The ignition difference coefficient is calculated based on the ignition performance function relationship between the test sample and the reference sample. The ignition difference coefficient is the ratio of the integral area difference between the ignition performance function relationship curves of the test sample and the reference sample to the maximum integral area of ​​the two curves.

[0016] Furthermore, two or three fast-burning energetic materials are used as ignition powders, and five filling densities are selected for each ignition powder.

[0017] Furthermore, the ignition powder includes: nitrocellulose, NG absorbing powder, rapid burning powder for pistol bullets, nail powder and rapid burning powder for shotguns.

[0018] Furthermore, the filling density of the ignition charge is: 6g / dm 3 , 8g / dm 3 , 10g / dm 3 , 12g / dm 3 , 14g / dm 3 .

[0019] Furthermore, the propellant charge density does not exceed 250 g / dm 3 .

[0020] Furthermore, the ignition powder has a moisture content of less than 2%.

[0021] Furthermore, the ignition performance function relationship expression is: Among them, α and v are the dimensionless characteristic coefficients of the static combustion ignition transfer time of the propellant; β and λ are the dimensionless characteristic coefficients of the static combustion ignition transfer intensity of the propellant.

[0022] Furthermore, the ignition difference coefficient calculation formula is:

[0023]

[0024] Where η j is the ignition variability coefficient, f 1参 (ε) is the T in the functional expression of the ignition performance of the reference sample cj , f 2参 (ε) is the Γ in the expression of the ignition performance function of the reference sample cj , f 1试 (ε) T in the functional expression of the ignition performance of the test sample cj , f 2试 (ε) Γ in the expression of the ignition performance function of the test sample cj .

[0025] Compared with the prior art, the present invention has the following beneficial effects: by adopting different ignition powders and ignition powder amounts to change the propellant ignition conditions to conduct a propellant static combustion test, the propellant point ignition performance characteristic parameters are extracted and analyzed based on the test results, the propellant point ignition performance characterization is achieved, and the problem that the propellant point ignition performance cannot be characterized and cannot guide the charge design work is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a flow chart of the test method for characterizing the static combustion ignition performance of propellant;

[0027] Figure 2 This is a schematic diagram of the hardware part of the static combustion ignition performance test of propellant;

[0028] Figure 3 The static combustion point ignition characteristic curve of the test propellant in the embodiment;

[0029] Figure 4 The static combustion point ignition characteristic curve of the reference propellant in the embodiment;

[0030] Figure 5 The static combustion point ignition performance and ignition time characteristic curve of the test propellant and the reference sample in the embodiment;

[0031] Figure 6 It is the static combustion point ignition performance and ignition intensity characteristic curve of the test propellant and reference sample in the embodiment. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0033] like Figure 1 As shown in the figure, the static combustion ignition performance characterization test method of propellant includes:

[0034] Prepare test samples and reference samples. The test samples are test groups composed of the same propellant to be tested, different ignition charges and different filling densities. The test group can use 2 or 3 fast-burning energetic materials as ignition charges. Nitrocellulose, NG absorbing powder, fast-burning charges for pistol bullets, nail charges and fast-burning charges for shotguns can be used as ignition charges. The basis for selecting the type of ignition charge is: according to the difference in burning speed between the ignition charge and the test sample and the reference sample itself, it is necessary to select an energetic material with a faster burning speed as the ignition charge. The basis for the selection of the present invention is: 120g / dm 3 Carry out closed explosive test under filling density. The material whose burning time of ignition powder and the burning time of test sample (ignited propellant) are less than 5% can be used as ignition powder. Take 5 filling densities for each ignition powder, such as 6g / dm 3 , 8g / dm 3 , 10g / dm 3 , 12g / dm 3 , 14g / dm 3 The selection criteria are: a set of curve fitting ensures that at least 5 points can fit a functional relationship with small errors and can reduce the number of experiments (the experiment takes a long time to obtain a set of available parameters); 6g / dm 3 The basis for determination is that when the test is below this value, there is a phenomenon of failure to ignite. 3 The basis for determination is that when the test is performed above this value, the ignition will be more violent, which may cause safety hazards; 2g / dm 3 The gradient value is determined based on the fact that isogradient transformation makes it easier to find the ignition law. The moisture content of the ignition powder is controlled below 2%. The density of the propellant filling does not exceed 250g / dm 3 , recommended but not limited to 200g / dm 3 .250g / dm 3 The basis for determination is that if the value is higher than this value, there will be safety hazards and even explosion accidents.

[0035] The reference sample and the test sample differ only in the propellant. The propellant is samples from different batches in the scientific research and production process of propellant or samples before and after scientific research optimization iterations.

[0036] The hardware part of the static combustion ignition performance test of propellant is as follows Figure 2 As shown, it mainly includes a closed exploder body, an ignition plug, a pressure measuring plug, a piezoelectric pressure sensor (1), a charge amplifier, a high-frequency data collector, etc. Among them, the closed exploder body includes but is not limited to a closed exploder with a volume of 50ml, 100ml, 200ml or larger. The piezoelectric pressure sensor has a range of 0 to 600MPa, and the high-frequency data collector has a sampling frequency range of 200kHz to 10MHz.

[0037] The closed explosive device is used to load the test sample and the reference sample respectively and conduct the static combustion ignition performance test, collect the PT curve, and process the PT curve set after the test to extract and calculate the characteristic values ​​and characteristic curves of each test ignition combustion, ignition transfer combustion and propellant combustion. Specifically, the maximum pressure is extracted on the PT curve, and the differential curve and intensity curve are calculated according to GJB770B-2022703.1; the ignition pressure and ignition time are obtained based on the inflection point of the differential curve, and the absolute ignition point is obtained based on the intensity curve to obtain the ignition transfer intensity Γ cj , further find the ignition time point according to the coordinates, calculate the ignition pressure ratio ε according to the ignition pressure and the maximum pressure, and calculate the ignition combustion time T according to the ignition time and ignition time cj .

[0038] Based on the ignition pressure ratio ε, the ignition combustion time T cj and fire intensity Γ cj The ignition performance function relationship between the test sample and the reference sample is established respectively, where the ignition pressure accounts for 0<ε<15%. The burning time T of the propellant from ignition to combustion to the absolute complete ignition point cj = The time value corresponding to the point ψ = 0.15 in the propellant intensity curve (Γ-ψ) minus the ignition charge combustion time T ig The intensity value Γ corresponding to the absolute complete ignition point of the propellant combustion cj is the intensity value corresponding to the point ψ=0.15 in the propellant intensity curve (Γ-ψ), and the definition is: The static combustion ignition performance function of propellant is: Among them, α and v are dimensionless characteristic coefficients of static combustion ignition time of propellant; β and λ are dimensionless characteristic coefficients of static combustion ignition intensity of propellant. The smaller the α value, the smaller the v value, the easier the propellant is to ignite and burn; the smaller the β value, the larger the λ value, the easier the propellant is to ignite and burn.

[0039] The ignition difference coefficient is calculated based on the ignition performance function relationship between the test sample and the reference sample. The ignition difference coefficient is the ratio of the integral area difference between the ignition performance function relationship curve of the test sample and the reference sample to the maximum integral area of ​​the two curves. The ignition difference coefficient calculation formula is:

[0040]

[0041] Where η j is the ignition variability coefficient, f 1参 (ε) is the T in the functional expression of the ignition performance of the reference sample cj , f 2参 (ε) is the Γ in the expression of the ignition performance function of the reference sample cj , f 1试(ε) T in the functional expression of the ignition performance of the test sample cj , f 2试 (ε) Γ in the expression of the ignition performance function of the test sample cj The ignition performance difference coefficient tends to zero, indicating that the ignition performance of the two samples is consistent.

[0042] Example

[0043] The following static combustion ignition transfer performance test is carried out on a certain artillery propellant to achieve the characterization of its static combustion ignition transfer performance.

[0044] Step 1: Carry out the static combustion ignition test of the propellant according to the scheme in Table 1, and collect the complete Pt curve to form a Pt curve set.

[0045] Table 1. Static combustion ignition test plan for a certain artillery propellant

[0046]

[0047] The pressure-time curve was analyzed to obtain the static combustion ignition characteristic parameters and static combustion ignition characteristic curves corresponding to different ignition materials of the test sample and the reference sample. The static combustion ignition characteristic parameter results are shown in Table 2 and Table 3, and the static combustion ignition characteristic curve is shown in Figure 3 , Figure 4 shown.

[0048] Table 2. Static combustion ignition characteristic parameters of a gun propellant test sample

[0049]

[0050] Table 3. Static combustion ignition characteristic parameters of a certain artillery propellant reference sample

[0051]

[0052]

[0053] The static combustion ignition transfer characteristic values ​​in Table 2 and Table 3 were subjected to correlation analysis, feature dimension reduction and feature fitting to establish the ignition intensity ratio ε and the static combustion ignition transfer time T of the propellant. cj , Static combustion intensity of propellant Γ cj The static combustion ignition performance relationship between the test propellant and the reference sample is as follows: Figure 5 , 6 The static combustion ignition performance relationship of the propellant test sample in this embodiment is: The static combustion ignition performance of the reference sample is

[0054]

[0055] The ignition difference coefficient is calculated according to the ignition difference coefficient calculation formula. In this embodiment, the ignition difference coefficient is 0.2271, which is equivalent to a static ignition performance difference of 22.71% between the propellant test sample and the reference sample.

[0056] The invention is applicable to the ignition performance characterization of static combustion of propellants for medium and large caliber light weapons and propellants for all artillery.

Claims

1. The static combustion ignition performance characterization test method of propellant is characterized by: include: Prepare test samples and reference samples. The test samples are a test group consisting of the same propellant to be tested, different ignition charges and different filling densities. The reference samples and test samples are samples from different batches of the propellant scientific research and production process or samples before and after scientific research optimization iterations. Use a closed explosive to load the test sample and reference sample respectively and carry out static combustion ignition performance test, and collect the pressure-time curve; The pressure-time curve is processed and calculated to obtain the static combustion ignition characteristic parameters corresponding to different ignition charges and different ignition charge amounts of the test sample and the reference sample: ignition pressure P ig , Fire burning time T cj , fire transmission intensity Γ cj , the maximum pressure generated by the combustion of propellant P m ; Based on the ignition pressure ratio ε, the ignition combustion time T cj and fire intensity Γ cj The ignition performance function relationship between the test sample and the reference sample is established respectively, in which the ignition pressure accounts for The ignition difference coefficient is calculated based on the ignition performance function relationship between the test sample and the reference sample. The ignition difference coefficient is the ratio of the integral area difference between the ignition performance function relationship curves of the test sample and the reference sample to the maximum integral area of ​​the two curves.

2. The static combustion ignition performance characterization test method of propellant according to claim 1 is characterized in that: Two or three fast-burning energetic materials are used as ignition materials, and five filling densities are selected for each ignition material.

3. The static combustion ignition performance characterization test method of propellant according to claim 1 is characterized in that: Ignition powder includes: nitrocellulose, NG absorbing powder, rapid-burning powder for pistol bullets, nail powder and rapid-burning powder for shotguns.

4. The static combustion ignition performance characterization test method of propellant according to claim 1 is characterized in that: The filling density of ignition powder is: 6g / dm 3 , 8g / dm 3 , 10g / dm 3 , 12g / dm 3 , 14g / dm 3 .

5. The static combustion ignition performance characterization test method of propellant according to claim 1 is characterized in that: The propellant charge density shall not exceed 250g / dm 3 .

6. The static combustion ignition performance characterization test method of propellant according to claim 1 is characterized in that: The moisture content of ignition powder is below 2%.

7. The static combustion ignition performance characterization test method of a propellant according to any one of claims 1 to 6, characterized in that: The ignition performance function relationship expression is: Among them, α and v are the dimensionless characteristic coefficients of the static combustion ignition transfer time of the propellant; β and λ are the dimensionless characteristic coefficients of the static combustion ignition transfer intensity of the propellant.

8. The static combustion ignition performance characterization test method of propellant according to claim 7 is characterized in that: The calculation formula of ignition difference coefficient is: Where η j is the ignition variability coefficient, f 1参 (ε) is the T in the functional expression of the ignition performance of the reference sample cj , f 2参 (ε) is the Γ in the expression of the ignition performance function of the reference sample cj , f 1试 (ε) T in the functional expression of the ignition performance of the test sample cj , f 2试 (ε) Γ in the expression of the ignition performance function of the test sample cj .

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