Test method for characterizing the static combustion ignition performance of propellants
By using samples with different ignition propellants and packing densities in static combustion ignition performance tests of propellants, collecting pressure-time curves and calculating characteristic parameters, an ignition performance function relationship was established, solving the problem of inconsistent ignition transmission of propellants, and realizing effective characterization of propellant ignition performance and guidance for charge design.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- LUZHOU NORTH CHEM IND
- Filing Date
- 2024-11-19
- Publication Date
- 2026-05-26
Smart Images
Figure CN119395212B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of propellant testing, specifically a test method for characterizing the static combustion point ignition performance of propellants. Background Technology
[0002] Propellant is the energy substance within a tube weapon that provides propulsion for the projectile. It generates gas pressure through combustion within the barrel, and the expansion of the gas propels the projectile. Currently, most propellant technology problems approximate the ignition process using the assumption of "instantaneous and comprehensive ignition." However, the following issues have been discovered during propellant performance testing.
[0003] (1) Inconsistent ignition and propulsion during internal ballistic action
[0004] In classical internal ballistics theory, to facilitate the description of the relationship between the projectile's in-bore motion and the dynamic combustion performance of the propellant, the basic internal ballistic equations were established. These equations are based on the geometric combustion law, namely the assumption that "all propellant surfaces ignite simultaneously." However, in actual static combustion tests of propellant, a significant inconsistency in ignition transmission was observed.
[0005] (2) Large differences in repeated tests during the initial combustion stage
[0006] During the closed-circuit test, it was found that when the same propellant was tested under the same conditions, the pressure change curve showed poor repeatability in the initial combustion stage, which was obviously due to the lack of thorough research on the propellant ignition problem.
[0007] The main causes of the above problems are inconsistent static combustion ignition time of the propellant, inconsistent ignition intensity of the propellant, and delayed surface ignition between propellant particles (non-instantaneous comprehensive ignition). Summary of the Invention
[0008] In order to characterize the performance of the static combustion point ignition process of propellants, this application provides a test method for characterizing the static combustion point ignition performance of propellants.
[0009] The technical solution adopted by the present invention to solve the above problems is:
[0010] Test methods for characterizing the static combustion ignition performance of propellants include:
[0011] Test samples and reference samples were prepared. The test samples consisted of a test group composed of the same propellant to be tested, different ignition propellants, and different packing densities. The reference samples and test samples were samples from different batches in the research and production process of the propellant or samples before and after research optimization and iteration.
[0012] A closed ignition device was used to fill the test sample and the reference sample respectively, and static combustion ignition performance tests were carried out, and pressure-time curves were collected.
[0013] The pressure-time curves were processed and calculated to obtain the static combustion ignition characteristic parameters corresponding to different ignition propellants and different propellant quantities for the test sample and reference sample: ignition pressure P ig ignition and combustion time T cj , fire intensity cj The maximum pressure P generated by the combustion of the propellant m ;
[0014] Based on ignition pressure ratio ε and ignition time T cj and the intensity of fire transmission cj Establish functional relationships between the ignition performance of the test sample and the reference sample, respectively, where the ignition pressure accounts for a certain percentage.
[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 difference in the integral area of the ignition performance function relationship curves of the test sample and the reference sample to the maximum value of the integral area of the two curves.
[0016] Furthermore, two or three types of fast-burning energetic materials are used as igniters, with five loading densities for each type of igniter.
[0017] Furthermore, the ignition powder includes: nitrocellulose, NG-containing absorbent powder, pistol ammunition quick-burning powder, nail gun powder, and shotgun quick-burning powder.
[0018] Furthermore, the charge density of the ignition powder is 6 g / dm³. 3 8g / dm 3 10g / dm 3 12g / dm 3 14g / dm 3 .
[0019] Furthermore, the propellant loading density does not exceed 250 g / dm³. 3 .
[0020] Furthermore, the moisture content of the ignition powder is below 2%.
[0021] Furthermore, the functional relationship expression for ignition performance is as follows: Where α and v are dimensionless characteristic coefficients of the static combustion ignition time of the propellant; β and λ are dimensionless characteristic coefficients of the static combustion ignition intensity of the propellant.
[0022] Furthermore, the formula for calculating the ignition difference coefficient is:
[0023]
[0024] In the formula, η j f is the ignition difference coefficient. 1参 (ε) represents T in the functional relationship expression of the ignition performance of the reference sample. cj f 2参 (ε) represents Γ in the functional relationship expression of the ignition performance of the reference sample. cj f 1试 (ε) T in the functional relationship expression of the ignition performance of the test sample cj f 2试 (ε) Γ in the functional relationship expression of the ignition performance of the test sample cj .
[0025] The advantages of this invention compared to the prior art are as follows: by using different ignition propellants and ignition propellant amounts to change the ignition conditions of the propellant and conducting static combustion tests on the propellant, the characteristic parameters of the propellant's ignition and propagation performance are extracted and analyzed from the test results, thus realizing the characterization of the propellant's ignition and propagation performance and solving the problem that the propellant's ignition and propagation performance cannot be characterized and cannot guide the design of the propellant charge. Attached Figure Description
[0026] Figure 1 Flowchart of the test method for characterizing the static combustion point ignition performance of propellants;
[0027] Figure 2 A schematic diagram of the hardware components for a static combustion ignition performance test of propellants;
[0028] Figure 3 The static combustion point ignition characteristic curve of the test propellant in the example;
[0029] Figure 4 This is the static combustion point ignition characteristic curve of the reference propellant in the example;
[0030] Figure 5 The static combustion point ignition performance and ignition time characteristic curves of the test propellant and reference sample in the examples are shown.
[0031] Figure 6 The static combustion point ignition performance and ignition intensity characteristic curves of the test propellant and reference sample in the examples are shown. Detailed Implementation
[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0033] like Figure 1 As shown, the test method for characterizing the static combustion point ignition performance of propellants includes:
[0034] Test samples and reference samples are prepared. The test samples consist of a test group composed of the same propellant to be tested, different igniters, and different packing densities. The test group can use two or three fast-burning energetic materials as igniters, such as nitrocellulose, NG-containing absorbent powder, fast-burning propellants for pistol ammunition, nail gun propellants, and fast-burning propellants for shotguns. The selection of the igniter type is based on the difference in burning rate between the igniter and the test and reference samples; a faster-burning energetic material needs to be selected. In this invention, the selection is based on 120 g / dm³. 3 A closed-circuit test was conducted at various packing densities. Substances whose ignition propellant burning time accounts for less than 5% of the burning time of the test sample (the propellant being ignited) can be used as ignition propellants. Five packing densities were tested for each type of ignition propellant, such as 6 g / dm³. 3 8g / dm 3 10g / dm 3 12g / dm 3 14g / dm 3 The selection criteria were: a set of curve fittings should at least have 5 points that can fit a functional relationship with small error and reduce the number of experiments (obtaining a set of usable parameters takes a long time); 6g / dm 3 The basis for this determination is that below this value, ignition failure occurs during testing (14 g / dm). 3 The basis for this determination is that ignition was more violent when the value was higher than this during the test, posing a safety hazard; 2g / dm 3 The gradient value is determined based on the principle that isogradient transformation makes it easier to find the ignition pattern. The moisture content of the ignition propellant is controlled below 2%. The propellant loading density does not exceed 250 g / dm³. 3 Recommended, but not limited to, 200g / dm 3 250g / dm 3 The basis for this determination is that values exceeding this level could pose safety hazards or even cause explosions.
[0035] The reference sample and the test sample differ only in the propellant. The propellant is a sample from different batches during the research and production process of the propellant or a sample before and after research optimization and iteration.
[0036] Hardware components for static combustion ignition performance testing of propellants, such as Figure 2 As shown, it mainly includes a sealed burster body, an ignition plug, a pressure measuring plug, a piezoelectric pressure sensor (1 piece), a charge amplifier, and a high-frequency data acquisition unit. The sealed burster body includes, but is not limited to, sealed bursters with volumes of 50ml, 100ml, 200ml, or larger. The piezoelectric pressure sensor has a range of 0–600MPa, and the high-frequency data acquisition unit has a sampling frequency range of 200kHz–10MHz.
[0037] A closed-circuit ignition chamber was used to load test samples and reference samples, and static combustion ignition performance tests were conducted. PT curves were collected, and the PT curve sets were processed and calculated to obtain characteristic values and curves for each test ignition combustion, ignition propagation combustion, and propellant combustion. Specifically, the maximum pressure was extracted from the PT curves, and the differential curve and ignition benzene curve were calculated according to GJB770B-2022703.1. Ignition pressure and ignition time were obtained based on the inflection point of the differential curve, and the absolute ignition point was obtained based on the ignition benzene curve to obtain the ignition propagation benzene Γ. cj Further, the ignition time point is located based on the coordinates, the ignition pressure ratio ε is calculated based on the ignition pressure and the maximum pressure, and the ignition combustion time T is calculated based on the ignition time and the ignition time. cj .
[0038] Based on ignition pressure ratio ε and ignition time T cj and the intensity of fire transmission cj Establish functional relationships between the ignition performance of the test sample and the reference sample, respectively, where the ignition pressure accounts for a certain percentage. 0 < ε < 15%. The combustion time T of the propellant from ignition to the point of absolute complete ignition. cj The time value corresponding to the point ψ = 0.15 in the propellant intensity curve (Γ-ψ) is subtracted from the ignition time T. ig The saturation value Γ corresponding to the point where the propellant burns to its absolute complete ignition point. cj Let ψ = 0.15 be the propellant saturation value in the propellant saturation curve (Γ-ψ), defined as follows: The static combustion ignition performance function relationship of the propellant is as follows: Where α and v are dimensionless characteristic coefficients of the static combustion ignition time of the propellant; β and λ are dimensionless characteristic coefficients of the static combustion ignition intensity of the propellant. The smaller the value of α and v, the easier it is for the propellant to ignite and burn; the smaller the value of β and the larger the value of λ, the easier it is for the propellant to ignite and burn.
[0039] The ignition difference coefficient is calculated based on the functional relationship between the ignition performance of the test sample and the reference sample. The ignition difference coefficient is the ratio of the difference in the integral area of the ignition performance functional relationship curves of the test sample and the reference sample to the maximum value of the integral area of their curves. The formula for calculating the ignition difference coefficient is as follows:
[0040]
[0041] In the formula, η j f is the ignition difference coefficient. 1参 (ε) represents T in the functional relationship expression of the ignition performance of the reference sample. cj f 2参 (ε) represents Γ in the functional relationship expression of the ignition performance of the reference sample. cj f 1试(ε) T in the functional relationship expression of the ignition performance of the test sample cj f 2试 (ε) Γ in the functional relationship expression of the ignition performance of the test sample cj The coefficient of difference in ignition performance approaching zero indicates that the two samples have the same ignition performance.
[0042] Example
[0043] The following test was conducted on the static combustion point ignition performance of a certain artillery propellant to characterize its static combustion point ignition performance.
[0044] Step 1: Conduct static combustion ignition tests of the propellant according to the scheme in Table 1, and collect complete Pt curves to form a Pt curve set.
[0045] Table 1. Static Combustion Ignition Test Scheme for Propellant of a Certain Artillery Unit
[0046]
[0047] The pressure-time curves were analyzed to obtain the static combustion ignition characteristic parameters and static combustion ignition characteristic curves for different ignition propellants in the test samples and reference samples. The results of the static combustion ignition characteristic parameters are shown in Tables 2 and 3, and the static combustion ignition characteristic curves are shown in... Figure 3 , Figure 4 As shown.
[0048] Table 2. Static combustion ignition characteristic parameters of a test sample of propellant for a certain artillery piece
[0049]
[0050] Table 3. Static combustion ignition characteristic parameters of a reference sample of propellant for a certain artillery.
[0051]
[0052]
[0053] Correlation analysis, feature dimensionality reduction, and feature fitting were performed on the static combustion ignition characteristic values in Tables 2 and 3 to establish the ignition intensity ratio ε and the static combustion ignition time T of the propellant. cj Γ, static combustion ignition intensity of propellant cj The functional relationship between the test propellant and the reference sample is as follows: Figure 5 , 6 As shown. In this embodiment, the relationship between the static combustion point and ignition performance of the propellant test sample is as follows: The relationship between the static combustion point and ignition performance of the reference sample is as follows:
[0054]
[0055] The ignition difference coefficient was calculated according to the formula. In this embodiment, the ignition difference coefficient is 0.2271, which is equivalent to a 22.71% difference in static ignition performance between the propellant test sample and the reference sample.
[0056] This invention is applicable to the characterization of the ignition performance of static combustion of propellants for medium and large caliber light weapons and all artillery propellants.
Claims
1. A test method for characterizing the static combustion ignition performance of propellants, characterized in that, include: Test samples and reference samples were prepared. The test samples consisted of a test group composed of the same propellant to be tested, different ignition propellants, and different packing densities. The reference samples and test samples were samples from different batches in the research and production process of the propellant or samples before and after research optimization and iteration. A closed ignition device was used to fill the test sample and the reference sample respectively, and static combustion ignition performance tests were carried out, and pressure-time curves were collected. The pressure-time curves were processed and calculated to obtain the static combustion ignition characteristic parameters corresponding to different ignition propellants and different propellant quantities for the test sample and reference sample: ignition pressure P ig ignition and combustion time T cj , fire intensity cj The maximum pressure P generated by the combustion of the propellant m ; Based on ignition pressure ratio ε and ignition time T cj and the intensity of fire transmission cj Establish functional relationships between the ignition performance of the test sample and the reference sample, respectively, where the ignition pressure accounts for a certain percentage. 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 difference in the integral area of the ignition performance function relationship curves of the test sample and the reference sample to the maximum value of the integral area of the two curves.
2. The test method for characterizing the static combustion ignition performance of propellants according to claim 1, characterized in that, Two or three types of fast-burning energetic materials are used as igniters, and five filling densities are taken for each type of igniter.
3. The test method for characterizing the static combustion ignition performance of propellants according to claim 1, characterized in that, Ignition charges include: nitrocellulose, NG-containing absorbent powder, pistol ammunition quick-burning powder, nail gun powder, and shotgun quick-burning powder.
4. The test method for characterizing the static combustion ignition performance of propellants according to claim 1, characterized in that, The charge density of the ignition powder is 6 g / dm³. 3 8g / dm 3 10g / dm 3 12g / dm 3 14g / dm 3 .
5. The test method for characterizing the static combustion ignition performance of propellants according to claim 1, characterized in that, Propellant loading density not exceeding 250 g / dm 3 .
6. The test method for characterizing the static combustion ignition performance of propellants according to claim 1, characterized in that, The moisture content of the ignition powder is below 2%.
7. The test method for characterizing the static combustion ignition performance of propellants according to any one of claims 1-6, characterized in that, The functional relationship expression for ignition performance is: Where α and v are dimensionless characteristic coefficients of the static combustion ignition time of the propellant; β and λ are dimensionless characteristic coefficients of the static combustion ignition intensity of the propellant.
8. The test method for characterizing the static combustion ignition performance of propellants according to claim 7, characterized in that, The formula for calculating the ignition difference coefficient is: In the formula, η j f is the ignition difference coefficient. 1参 (ε) represents T in the functional relationship expression of the ignition performance of the reference sample. cj f 2参 (ε) represents Γ in the functional relationship expression of the ignition performance of the reference sample. cj f 1试 (ε) T in the functional relationship expression of the ignition performance of the test sample cj f 2试 (ε) Γ in the functional relationship expression of the ignition performance of the test sample cj .