• Title/Summary/Keyword: Pyrotechnics

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Synthesis and Characterization of Tetrazine Derivatives as High Energy Propellants (테트라진 계열의 추진 물질 합성 연구)

  • Lee, Woonghee;Park, Youngchul;Joo, Young-Hyuk
    • Journal of the Korean Society of Propulsion Engineers
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    • v.17 no.6
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    • pp.38-47
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    • 2013
  • Traditional propellants release toxic gases during combustion that are harmful to the environment. This study describes a novel synthetic process of two high nitrogen containing tetrazines, TATTz and BTATz, which can be adapted as solid fuels for a solution to environmental concerns. The compounds were characterized by NMR, IR spectroscopy, and differential scanning calorimetry(DSC). Detonation properties were calculated with the EXPLO5 program based on calculated heats of formation and measured densities.

The Study on the Synthesis of Propellant with High Nitrogen Content (고질소 추진물질 합성 연구)

  • Lee, Woonghee;Kim, Minjun;Park, Youngchul
    • Journal of the Korean Society of Propulsion Engineers
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    • v.19 no.3
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    • pp.96-102
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    • 2015
  • Traditional propellants emit toxic gases such as carbon dioxide and hydrogen chloride during combustion which are harmful to the environment. This study established a synthetic process of a high nitrogen containing derivative of tetrazine, 3,3-Azobis(6-Amino-1,2,4,5-Tetrazine) (DAAT), which can be applied as solid fuels for a solution to environmental concerns. Also, this paper described the detailed process and the analytic results of properties, which were not mentioned in previous reports. The compound was characterized by NMR, IR spectroscopy, and thermal, impact, and friction stability were measured. In addition, the heats of formation (${\Delta}H_f$) and detonation properties (pressure and velocity) of DAAT were calculated using Gaussian 09 and EXPLO5 programs.

Image processing method of two-phase bubbly flow using ellipse fitting algorithm (최적 타원 생성 알고리즘 기반 2상 기포 유동 영상 처리 기법)

  • Myeong, Jaewon;Cho, Seolhee;Lee, Woonghee;Kim, Sungho;Park, Youngchul;Shin, Weon Gyu
    • Journal of the Korean Society of Visualization
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    • v.19 no.1
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    • pp.28-35
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    • 2021
  • In this study, an image processing method for the measurement of two-phase bubbly flow is developed. Shadowgraphy images obtained by high-speed camera are used for analysis. Some bubbles are generated as single unit and others are overlapped or clustered. Single bubbles can be easily analyzed using parameters such as bubble shape, centroid, and area. But overlapped bubbles are difficult to transform clustered bubbles into segmented bubbles. Several approaches were proposed for the bubble segmentation such as Hough transform, connection point method and watershed. These methods are not enough for bubble segmentation. In order to obtain the size distribution of bubbles, we present a method of splitting overlapping bubbles using watershed and approximating them to ellipse. There is only 5% error difference between manual and automatic analysis. Furthermore, the error can be reduced down to 1.2% when a correction factor is used. The ellipse fitting algorithm developed in this study can be used to measure bubble parameters accurately by reflecting the shape of the bubbles.

Investigation of Thermal/hygrothermal Aging Effects on the Ignition Characteristics of Ti Metal-based Pyrotechnics and Construction of the Aging Models (열/수분노화로 인한 Ti 금속 기반의 파이로 물질의 점화 성능 변화와 노화 모델 제시)

  • Oh, Juyoung;Yoh, Jai-ick
    • Journal of the Korean Society of Propulsion Engineers
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    • v.25 no.3
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    • pp.26-41
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    • 2021
  • Titanium hydride potassium perchlorate (THPP) has played an important role as initiators of the propulsion system. However, the 'aging' may cause performance degradation and even give rise to a failure in the total system. In this study, various hygrothermal aging conditions were considered and the aging effects on thermodynamic and ignition characteristics of THPP are provided via thermal analysis and ignition measurements. Also, physical-chemical changes were identified by morphological analysis. In conclusion, thermal aging led to Eα decrease-high reactivity due to oxidizer decomposition whereas hygrothermal aging gave rise to an opposite tendency by fuel oxidation.

폭발계열을 중심으로 한 화공기술(1)

  • Kim, Chang-Sik
    • Defense and Technology
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    • no.2 s.276
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    • pp.30-39
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    • 2002
  • 화공기술이란 연소와 폭발성을 갖는 단일 또는 복합 물질을 기제로 하여 제품을 사용 목적에 맞도록 제조와 응용하는 기술을 의미하며, 화약의 에너지 물질로서 제조된 다양한 제품을 화공품(Pyrotechnics)이라고 한다. 우리 주변에서 흔히 볼 수 있는 것은 산업용으로 성냥, 딱총약, 엽총화약, 연화, 광산용의 도화선, 도폭선, 각종 뇌관류 등이 있고, 군용으로는 발사화기와 로케트 추진기관의 점화계열, 탄두/탄약의 폭발계열, 신호탄, 연막, 조명탄 등을 들 수 있다.

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Synthesis and Crystallization of Hydrazinium Nitroformate(HNF) as Eco-friendly Oxidizer (친환경 산화제 HNF 합성 및 결정화 연구)

  • Kim, Jina;Kim, Min Jun;Min, Byoung Sun
    • Journal of the Korean Society of Propulsion Engineers
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    • v.19 no.4
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    • pp.69-76
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    • 2015
  • Recently, environmental sustainability of the transitional explosives and propellants is an issue of growing importance in energetic materials. For examples, ammonium perchlorate(AP) as an solid propellants oxidizer could create a poisonous gas and atmospheric pollutions, such as HCl. Among the several oxidizers, hydrazinium nitroformate(HNF) is an effective candidate substance for eco-friendly oxidizer, which has high density, pressure index, and less smog generating property during combustion for the Divert and Attitude Control System(DACS). This study was confirmed a synthesis through various conditions, was performed for the essential data of solubility the crystallization process. Also, crystallization process such as cooling, drowning-out and sonication were performed.

Synthesis of a Nitrogen-rich Insensitive Energetic Material, DNAM(Dinitroammeline) (고질소 둔감에너지 물질인 DNAM(Dinitroammeline) 합성공정 개발)

  • Sul, Minjung;Kim, Minjun;Kim, Jinseuk;Kim, Seunghee
    • Journal of the Korean Society of Propulsion Engineers
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    • v.20 no.1
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    • pp.50-57
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    • 2016
  • We studied the Lab-scale process for the development of DNAM in aspect of safety and overall efficiency. Melamine is used for starting material of process, DNAM was synthesized by oxidation and nitration reaction. In order to optimize the process parameters with the product in higher yield and purity, a systematic study with variation of different parameters like molar ratio of nitrating mixture, conditioning time and order of reactant was carried out. The optimized reaction conditions for the synthesis of DNAM were : conditioning time of $3{\pm}3.5$ hour and nitrating mixture in 1:1.4 molar ratio. In order to proceed a stable reaction, melamine was added with enough time to relieve reaction heat. From these reaction condition, DNAM could be obtained in a yield of more than 60%.

Crystallization of Hydrazinium Nitroformate(HNF) as Eco-friendly Oxidizer (친환경 산화제 HNF 결정화 연구)

  • Kim, Jina;Kim, Min Jun;Min, Byoung Sun
    • Journal of the Korean Society of Propulsion Engineers
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    • v.20 no.6
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    • pp.76-82
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    • 2016
  • Recently, environmental sustainability of the transitional explosives and propellants is an issue of growing importance in energetic materials. For examples, ammonium perchlorate(AP) as an solid propellants oxidizer could create a poisonous gas and atmospheric pollutions, such as HCl. Among the several oxidizers, hydrazinium nitroformate(HNF) is an effective candidate substance for eco-friendly oxidizer, which has high density, pressure index, and less smog generating property during combustion for the thrust control system. This study was controlled the size distribution and shapes through various conditions. Length and diameter ratio(L/D) of crystals has below 1 : 3, and the particle size was two types of $200{\mu}m$ and $50{\mu}m$.

Synthesis and Characterization of Insensitive Energetic Plasticizer (둔감 에너지 가소제 합성 및 특성 분석)

  • Lee, Woonghee;Kim, Minjun;Park, Youngchul;Lee, Bumjae
    • Journal of the Korean Society of Propulsion Engineers
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    • v.20 no.6
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    • pp.11-17
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    • 2016
  • BTTN and TMETN are representative energetic plasticizers used for various propellants. However these compounds are sensitive relatively. So, in order to develop insensitive energetic plasticizer, this study attempted to synthesize derivative of triazole, 4,5-bis(azidomethyl)-(2-methoxyethyl)-1,2,3- triazole (DAMETR). Also, the prepared compound was characterized by NMR, IR spectroscopy, and physicochemical properties such as glass transition temperature, melting point, decomposition temperature, density, viscosity and impact sensitivity. In addition, the heats of formation (${\Delta}H_f$) and detonation properties (pressure and velocity) of DAMETR were calculated using Gaussian 09 and EXPLO5 programs. Especially, 1-DAMETR(>50 J) was more insensitive than BTTN(1 J) and TMETN(9.2 J).

Study on the Performance Evaluation of the Explosive Bolt that has been Natural Aging (자연 노화된 폭발볼트의 성능 평가에 관한 연구)

  • Kim, Dongjin;Jeong, Donghee;Lee, Yeungjo;Lee, Youngwoo
    • Journal of the Korean Society of Propulsion Engineers
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    • v.21 no.3
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    • pp.84-90
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    • 2017
  • Explosive bolt is coupled in a variety of guided weapons and space projectiles, to perform the separation function. Thus, the role of the explosive bolt in guided weapons systems is very important, as it can cause failure of the entire system in the case of mission failure. For this reason, the design life prediction for explosive bolt is highly and frequently required recently, but its accurate prediction method has not been presented. In order to apply the existing accelerated aging process, we should know the activation energy and the acceleration factor of the explosive bolt. Since the information required for accelerated aging is not presently secured, it is difficult to predict the design life of explosive. Thus, in the present study, we have evaluated the performance of actual explosive bolts in the condition of natural aging over 10 years in order to present a minimum design life.