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Technical Notes
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Technical Trend of Supercavitating Rocket Propulsion System
초공동 로켓 추진기관의 국내외 기술 동향
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Seongpil Joo, Seonuk Heo, Junyoung Heo, Jinho Hyon
주성필, 허선욱, 허준영, 현진호
- As the weapons systems of neighboring countries become more sophisticated and diverse, the development of various propulsion system to strengthen defense capabilities …
- As the weapons systems of neighboring countries become more sophisticated and diverse, the development of various propulsion system to strengthen defense capabilities should be required. This paper emphasizes the need for the development of an anti-submarine/anti-battleship system that can be used on submarines and ships. The supercavitating propulsion system uses seawater as an oxidizer in underwater environment and uses a solid propellant containing a metal that easily reacts with the sea water. In order to develop supercavitating propulsion system, we studied overseas weapons system and surveyed technological trends of various research institutes. In addition, we summarized domestic research results and introduces necessary technological elements. - COLLAPSE
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Technical Trend of Supercavitating Rocket Propulsion System
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Research Article
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Development and Validation of a Detailed Mechanism Generated by the Reaction Mechanism Generator for High-Temperature Ethane Dry Reforming
Reaction mechanism generator를 이용한 고온 환경 에탄 건식 개질 상세 메커니즘 생성 및 검증 연구
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Woorin Kang, Moon Soo Bak
강우린, 박문수
- A detailed kinetic mechanism of ethane dry reforming in thermal plasma was generated using the reaction mechanism generator(RMG). Although the temperature of …
- A detailed kinetic mechanism of ethane dry reforming in thermal plasma was generated using the reaction mechanism generator(RMG). Although the temperature of thermal plasmas exceeds typical combustion temperatures, chemical mechanisms suitable for this high-temperature range have been scarce. Therefore, considering the reaction temperature of thermal plasma, we attempted to generate a mechanism for a temperature range of 1500-4500 K, incorporating pressure-dependent reactions, in a systematic manner using RMG, and tested its predictive performance. The final mechanism consisted of 49 species and 652 reactions, including C3 intermediate hydrocarbons that are not present in Gri-Mech 3.0. To evaluate the predictive performance of the generated mechanism, numerical simulations of a reactor network model for ethane dry reforming using atmospheric-pressure microwave plasma were conducted, and the results were compared with previously measured data as well as those obtained using Gri-Mech 3.0. The simulated concentrations showed good agreement with values measured using gas chromatography. From reaction path analysis, it was found that the reaction pathways most responsible for H2 production were hydrogen abstraction reactions from hydrocarbons smaller than C2 in the plasma stream, and from hydrocarbons larger than C2 in the surrounding stream. Notably, Gri-Mech 3.0 has been successful in analyzing high-temperature dry reforming of light hydrocarbons as it includes most of the key reaction pathways. - COLLAPSE
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Development and Validation of a Detailed Mechanism Generated by the Reaction Mechanism Generator for High-Temperature Ethane Dry Reforming
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Technical Notes
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Recent Research Trends in Ammonia Reaction Mechanism
암모니아 반응 메커니즘 연구 동향
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Donghyun Kim, Jiwon Kim, Sungwoo Park
김동현, 김지원, 박성우
- This paper reviews recent advancements in ammonia reaction mechanisms, focusing on essential combustion characteristics such as laminar burning velocity, ignition delay time, …
- This paper reviews recent advancements in ammonia reaction mechanisms, focusing on essential combustion characteristics such as laminar burning velocity, ignition delay time, and NOx emissions. As a carbon-free fuel, ammonia is attracting growing interest as a potential alternative energy source. However, its slow combustion characteristics and high NOx emissions present considerable technical challenges. To address these issues, research has aimed at improving ammonia’s combustion properties, resulting in the development of various reaction mechanisms that enhance performance. This review evaluates these models’ predictive accuracy for NOx emissions, particularly under high-pressure conditions. Furthermore, the paper highlights future research directions for optimizing ammonia combustion models to support the development of low-emission gas turbine technologies. - COLLAPSE
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Recent Research Trends in Ammonia Reaction Mechanism
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Research Article
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Fast Pyrolysis of Ethanol Under High Pressure Conditions
고압 조건에서 에탄올의 급속 열분해 특성에 대한 연구
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Hwasup Song, Guillaume Vanhove
송화섭, VanhoveGuillaume
- The feasibility of high pressure pyrolysis experiment in a rapid compression machine is tested by using ethanol as a reactant. A premixed …
- The feasibility of high pressure pyrolysis experiment in a rapid compression machine is tested by using ethanol as a reactant. A premixed homogeneous ethanol-nitrogen-argon mixture is prepared and compressed to reach 880 K and 20 bar condition and the mixture undergoes pyrolysis, which is validated by direct sampling of the compressed mixture and conducting speciation through a gas chromatography. Over 10 species are detected and an up-to-date ethanol kinetic model is applied to gain insight into the formation of these intermediate species, which reveals some, but not all, pyrolysis pathways. Results suggest that further studies on the ethanol kinetics are necessary regarding the findings from this study, for example pyrolysis experiments with a non-diluted reactant could propose some reaction pathways accompanying exothermicity. - COLLAPSE
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Fast Pyrolysis of Ethanol Under High Pressure Conditions
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Research Article
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Experimental Study on Thermal Decomposition Characteristics of Supercritical n-Dodecane by Using a Batch Reactor System
배치반응기 실험장치를 이용한 초임계 n-dodecane의 열분해 특성 연구
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Seung Mook Park, Seung Hyeon Lee, Jun Su Kang, Hyung Ju Lee
박승묵, 이승현, 강준수, 이형주
- In an active regenerative cooling system for hypersonic cruise vehicles, hydrocarbon aviation fuel is used as a coolant, absorbing heat within the …
- In an active regenerative cooling system for hypersonic cruise vehicles, hydrocarbon aviation fuel is used as a coolant, absorbing heat within the system to reach a supercritical state. This causes the fuel to undergo endothermic decomposition into hydrogen and various low-molecular-weight hydrocarbons, significantly impacting the performance and efficiency of the regenerative cooling system. In this study, an experimental system was established to investigate the thermal cracking characteristics of hydrocarbon aviation fuel under various supercritical conditions. The system design, experimental methods, and analysis techniques are described, and pyrolysis experiments of n-dodecane were conducted to compare the results with existing experimental data. In particular, the activation energy was obtained to confirm the reliability of the batch reactor experimental system. - COLLAPSE
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Experimental Study on Thermal Decomposition Characteristics of Supercritical n-Dodecane by Using a Batch Reactor System
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Research Article
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Effects of Pyrolysis Products on Ignition Delay Time of an Endothermic Fuel at Low Pressure
저압 조건에서 흡열연료의 점화지연시간에 미치는 열분해 생성물의 효과
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Yejin Kang, Jiwung Choi, Jihwan Seong, Chae Hoon Sohn, Byunghun Jeong, Dongchang Park
강예진, 최지웅, 성지환, 손채훈, 정병훈, 박동창
- An endothermic fuel can be used as a coolant flowing through a cooling channel to prevent a combustor wall from being heated …
- An endothermic fuel can be used as a coolant flowing through a cooling channel to prevent a combustor wall from being heated as it absorbs additional heat through its endothermic reaction in addition to sensible heat absorption. Experiments and numerical simulations were conducted to analyze the ignition characteristics of a pyrolyzed fuel after it is injected into the combustion chamber. For this purpose, ignition delay time of the endothermic fuel, called TF-10, was measured at pressures close to operating conditions in a supersonic propulsion system, by using a constant-volume combustion chamber(CRU) and a shock tube. And, effects of pyrolysis products on ignition characteristics were also evaluated. TF-10 was found to exhibit greater pressure dependency and longer ignition delay times than Jet-A1. Among the pyrolysis products, ethylene(C2H4) was identified as a key species promoting ignition of TF-10. From sensitivity analyses, it is found that the specific reactions steps contribute to ignition acceleration of the mixture of TF-10 and ethylene. - COLLAPSE
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Effects of Pyrolysis Products on Ignition Delay Time of an Endothermic Fuel at Low Pressure
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Research Article
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ReaxFF Molecular Dynamics Simulation of Decomposition Mechanism and Kinetics of Liquid Hydrocarbon Fuel with Chemical Initiators
화학 개시제 첨가 액체 탄화수소 연료의 분해 메커니즘 및 반응 동역학에 관한 ReaxFF 분자동역학 시뮬레이션 연구
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Eungyo Choi, Byung Hun Jeong, Dongchang Park, Jung Hoon Park, Hyung Sub Sim
최은교, 정병훈, 박동창, 박정훈, 심형섭
- Understanding the decomposition processes of liquid hydrocarbon fuel with chemical initiators in the regenerative cooling systems of scramjet propulsion is crucial for …
- Understanding the decomposition processes of liquid hydrocarbon fuel with chemical initiators in the regenerative cooling systems of scramjet propulsion is crucial for improving its thermal management capabilities. This study theoretically investigates the effects of chemical initiators on the decomposition of exo-tetrahydrodicyclopentadiene(exo-THDCPD) using ReaxFF molecular dynamics(MD) simulations. Triethylamine(TEA), di-tert-butyl peroxide(DTBP), and cumene hydroperoxide(CHP) were examined as potential initiators, with simulations performed at various temperatures using the Berendsen thermostat and the CHON-2019 force field. MD results demonstrate that the initiators significantly affect conversion rates, product distributions, and reaction pathways. The addition of TEA and CHP enhanced fuel conversion by reducing activation energy, whereas DTBP had minimal impact. Product analysis revealed that DTBP increased the selectivity of C1-C4 paraffins and C2-C4 olefins, while TEA promoted CH4 and C2H6 formation. Moreover, CHP increased the selectivity of PAH precursors in the early stage, suggesting a higher tendency for coke formation. Reaction pathway analysis further confirmed that the initiators decompose, rapidly generating radicals that facilitate hydrogen abstraction and accelerate fuel decomposition. These findings provide a basis for optimizing fuel decomposition and thermal management performance through the use of chemical initiators. - COLLAPSE
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ReaxFF Molecular Dynamics Simulation of Decomposition Mechanism and Kinetics of Liquid Hydrocarbon Fuel with Chemical Initiators
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Research Article
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Optimization Study on Ammonia Vaporization Energy for Ammonia Power Generation in a Coal-Fired Power Plant
석탄화력 발전 플랜트의 암모니아 활용을 위한 암모니아 기화 에너지 최적화 연구
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Jonghwan An, Hyeonrok Choi, Won Yang, Seong-il Kim
안종환, 최현록, 양원, 김성일
- Ammonia is a carbon-free fuel that emits no carbon dioxide during combustion. Ammonia co-firing in coal-fired power plants is emerging as a …
- Ammonia is a carbon-free fuel that emits no carbon dioxide during combustion. Ammonia co-firing in coal-fired power plants is emerging as a transitional technology for carbon neutrality. Under the ammonia co-firing condition, the plant efficiency is affected by changes in the heat transfer mechanism to the steam cycle. Especially, the energy required for ammonia vaporization reduces plant efficiency. To evaluate these challenges, a process simulation model was developed for the 870 MWe supercritical power plant, integrating the boiler, turbine cycle, and flue gas treatment systems. Various heat recovery methods for ammonia vaporization were assessed, including flue gas sensible heat, steam sensible heat, and combinations of seawater with flue gas or steam. When seawater is utilized, it supplies most of the energy required for ammonia vaporization, thereby minimizing efficiency losses. In particular, the integration of seawater with flue gas reduces efficiency losses to nearly 0%, depending on the vaporizer installation location. Therefore, this method is considered the most efficient heat recovery method for ammonia vaporization in terms of overall plant performance. These findings provide practical insights into the utilization of ammonia co-firing, which can improve plant performance and reduce carbon emissions. - COLLAPSE
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Optimization Study on Ammonia Vaporization Energy for Ammonia Power Generation in a Coal-Fired Power Plant
Journal Informaiton
Journal of the Korean Society of Combustion
Journal of the Korean Society of Combustion
The Korean Society of Combustion
한국연소학회
39-103, Gwanak-ro 1, Gwanak-gu, Seoul 08826, Korea
Tel: +82-2-880-8626 / Fax: +82-505-070-8626 / E-mail: kosco@snu.ac.kr Copyright© The Korean Society of Combustion. Powered by APUB
Tel: +82-2-880-8626 / Fax: +82-505-070-8626 / E-mail: kosco@snu.ac.kr Copyright© The Korean Society of Combustion. Powered by APUB