Zhang Kangkang， Ding Sheng， Lu Qian， Wang Dong
School of Civil Engineering and Architecture， Anhui University of Technology， Ma’anshan 243002， China
Abstract
Objective Magnesium-polytetrafluoroethylene （Mg-PTFE） composite energetic material is an important energy carrier in aerospace and optoelectronic countermeasure applications. This material effectively improves the performance of thermal protection systems and base-bleed devices. Compared with most metal fuel mixtures， the Mg-PTFE composite generates significantly higher energy output and high-intensity spectral signals， making it an ideal payload for infrared decoy flares. However， the analysis of the combustion mechanism is challenging due to the complex multi-physics coupling involved. Consequently， the characterization of infrared radiation properties remains a weak link in numerical simulations. To address this issue， the gas-solid two-phase coupling mechanisms and infrared radiation characteristics are comprehensively analyzed based on computational fluid dynamics and radiation transport theories. The methods and results of this research provide robust theoretical support for the engineering design of related devices.
Methods In this study， experimental samples were first prepared by wet-mixing Mg-PTFE composite powder with dissolved Viton at a specified mass ratio， followed by pressing the mixture into a mold. Second， an optical diagnostic system was established to capture spectral data from the visible to the far-infrared bands. Third， a gas-solid two-phase coupling model was developed based on the Euler-Lagrange approach， wherein the high-temperature gas was treated as the continuous phase and the burning particles as the discrete phase. Source terms for mass， momentum， energy， and species were incorporated into the governing equations. A chemical kinetic mechanism comprising 15 species and 13 elementary reactions was employed to describe the Mg-PTFE combustion system， utilizing Arrhenius-type rate expressions to determine the generation rates of condensed-phase products. Fourth， the influence of participating media on radiative heat transfer was quantitatively described by the radiative transfer equation. Based on the probability density function sampling principle and the reverse Monte Carlo method， a custom simulation code was developed to evaluate the infrared radiation transmission characteristics of the heterogeneous combustion flame. Finally， the multiple radiation sources model was validated by comparing the numerical predictions with the experimental measurements.
Results and Discussion Based on the experimental tests， the combustion process was observed to comprise three stages： deflagration， stable combustion， and flameout. The stable combustion stage was characterized by high average infrared radiance and the formation of a stable effective radiation area. Through spectral data analysis， a continuous spectrum feature was observed， mainly originating from the radiation superposition of high-temperature gas molecules. The radiation peak， calculated by Wien’s displacement law， was located in the wavelength range of 1.2~1.4 µm. The strong selective radiation in the 4.2~4.6 µm wavelength range was attributed to the fundamental frequency vibration transitions of CO and CO2. Approximately 87% of the total radiation energy was distributed within the 1.0~5.0 µm wavelength band， while less than 5% was distributed in the 8.0~14.0 µm far-infrared wavelength band. The numerical simulation results showed high consistency with the experimental data. The simulated axial diffusion height of the high-temperature flame zone agreed well with the experimental measurements. Furthermore， the spatial distribution characteristics of the infrared radiance were evaluated. In the 3.0~5.0 µm wavelength band， 64.2% of the total radiation flux was contributed by the region near the solid burning surface， which was dominated by typical gray-body radiation. The high-temperature gas products contributed 13.65%， whereas the discrete burning particles contributed 21.32%. However， in the 8.0~14.0 µm wavelength band， the contribution rate of the burning particles dropped sharply to 4.61%. This phenomenon was caused by the high temperatures of the discrete burning particles， resulting in the dominance of short-wave radiation.
Conclusion In this study， the infrared radiation energy output characteristics of Mg-PTFE composites are investigated. Based on the experimental and numerical results， the Mg-PTFE composite exhibits a superposition of gray-body and selective radiation in the 0.8~14.0 µm wavelength band， with a peak located near 1.3 µm. Notably， this study innovatively achieves the quantitative decoupling characterization of multiphase radiation sources in the combustion flow field. Dynamically diffusing Mg particles are found to contribute 21.32% of the total radiation flux in the 3.0~5.0 µm wavelength band， whereas this contribution drops sharply to 4.61% in the 8.0~14.0 µm wavelength band. This explicitly demonstrates that the mid-infrared band is dominated by particle radiation， while the long-wave infrared band is governed by high-temperature gas radiation. The proposed approach is a highly effective numerical methodology for analyzing multiphase energetic materials. Furthermore， the numerical model is proven to be accurate. The validated approach can serve as a solid theoretical basis for the engineering design of related devices， such as infrared decoy flares.
Keywords： pyrotechnic compositions； combustion characteristics； infrared radiation； numerical simulation
Get Citation: Zhang Kangkang， Ding Sheng， Lu Qian， et al. Analysis of heterogeneous combustion and infrared radiation characteristics of magnesium particles in solid pyrotechnic compositions［J］. China Powder Science and Technology， 2027， 33（3）： 1-11.
Received：2026-05-08， Revised： 2026-06-09， Online： 2026-10-网上出版日期:26。
Funding： The research was supported by the National Key Research and Development Program of China (Grant No. 2025YFF0521003), the National Science and Technology Program Xiong’an New Area Science and Technology Innovation Special Project (Grant No. 2025XAGG0034), and the Young Teachers’ Scientific Research Foundation of Anhui University of Technology (Grant No. QZ202416).
DOI：10.13732/j.issn.1008-5548.2027.03.017
CLC No.: TK16
Type Code：A
Serial No.: 1008-5548（2027）03-0001-11
